Really all residential connections in the US are 220V split phase. The nice thing about split phase is that it is easy to well... split and run two linked 110V circuits, so most houses will have a few 220V items(ovens, airconditioner) and the rest wired half with phase A the other half with phase B. all of our consumer items expect this 110V
As to why split phase.... I am not really sure. Really, I wish a three phase residential had become normal instead. All the advantages of split phase but now your motors don't have to suck. I have heard a three phase residential connection is common in some parts of Germany, lucky bastards.
One interesting side note is how the US last mile distribution layout is different than germany. The US uses a lot more smaller transformers, really one per street. while germany uses fewer larger transformers, one per neighborhood. not sure which one is better I bet the german layout is more efficient. but I will note it is a lot easier to keep spares and change out a small transformer.
> Really all residential connections in the US are 220V split phase
Really all modern residential connections in Europe are 400V three phase electric power, capable to immediately power an electric motor without the need of capacitors.
No matter how you put it, the US residential power grid is conceptionally lagging.
How many residential appliances benefit from three phase, and is the benefit outweighed by the additional cost of more copper for the additional wires?
For example, a common big motor that needs a starter capacitor is a HVAC unit. Usually the copper to run those is extremely expensive, on the order of hundreds of dollars. Adding an additional wire may add an additional hundred dollars or more. By comparison, starter caps are quite cheap. $20 for a HVAC sized one. That also isn't counting any of the costs of three phase infrastructure for breakers etc.
That also isn't even counting that many appliances are moving to inverter based technologies that don't utilize induction motors at all, such as induction hobs. Or, many appliances with no benefit from extra phases (resistive heating devices such as ovens, dryers, toasters, etc).
Others have made the comment about lower current requirements at high voltage, but from a maintenance perspective, that $20 capacitor is a common failure part. Calling an HVAC repair company to diagnosis, parts, and labor it costs around $200 for anyone not electrically minded. Over the life of an AC unit, starter/run caps might have to replaced twice.
Even if an extra conductor in the line was a few hundred dollars, I’d rather have one less common failure point. In AZ AC is effectively required in the summer. AC outages are similar to winter furnace outages in northern areas. I have extra caps ready to deploy (we lose a cap about every 3 years across multiple units) but have never needed to unexpectedly replace copper.
Don't more modern AC units use VFDs that can run the compressor at arbitrary speeds, which is an improvement over both fixed 3 phase power and a starter capacitor? Maybe this tech hasn't made it into the house-sized units yet, though.
VFDs / "inverters" are happier on 3 phase as well, because the input rectifier caps can be much smaller. Whereas with single phase they have to be large enough to store energy for riding out the zero crossings of low power delivery.
I just replaced one of my two HVAC units with a variable speed compressor. It cost a lot more than the single or 2 stage units but it is more comfortable, uses less electricity, and runs at "low" to dehumidify longer.
Unfortunately these more modern units are still stupid expensive (in the US) compared to the older style. Unclear why; probably some sort of shenanigans with the HVAC manufacturing companies.
Little variable-speed units sold as ductless minisplits are fairly inexpensive in the US. They’re especially reasonable if you actually use them in a ductless configuration, because you don’t have to install ducts.
The fact that they might have a higher list price than a conventional single-speed outdoor unit and indoor evaporator coil is a red herring, as the conventional units can’t do anything on their own, and they need a furnace and a fan added to be useful.
My point isn't that the single individual wire to your HVAC is $100 vs. a $20 cap, though. There is likely hundreds or thousands of dollars of additional infrastructure needed to handle 3-phase input to a house. You have breakers, busbars, the transformer into the house is different, and on and on.
I agree that less failure points is nice, however you have to consider the tradeoff. Is it worth $100? Probably. What about $1000? $2000? If it's $2000, why not just get a more efficient inverter based one, which doesn't have a starter cap in the first place?
> There is likely hundreds or thousands of dollars of additional infrastructure needed to handle 3-phase input to a house. You have breakers, busbars, the transformer into the house is different, and on and on.
Split-phase system and 110V are currently more expensive in term of infrastructure.
The distribution itself is done in 3-phases power, even in the US.
The conversion to 110V and split phase is done in the last mile as close as possible to the termination point to limit losses. You have to have tiny power transformers everywhere and this has a significant cost.
At the opposite, end-to-end 400V three phases system requires to have only one large transformer by Area. Generally directly connected to High Voltage (20KV in Europe).
This isn't any different in the US vs. in Europe. Split phase is done at the last mile, just as it ought to be done in Europe for 3 phase power. I highly doubt entire neighborhoods or districts are serviced with a single extremely large 400V 3-phase transformer in Europe.
Standalone houses usually have multiple houses connected to one single transformer. How much depends on density of the houses. For apartment buildings and other dense power needs, there's high voltage directly into the complex, then it's stepped down within the complex to meet the needs.
Very interesting. Seems like that works much better as the power demand per house in the EU is lower, and the higher voltage gives you a bit more leeway. Frankly, I would be concerned about voltage drop for the far houses... even 400V is going to have some pretty beefy voltage drop under load unless the conductors are enormous.
One note regarding the pole transformers: in many parts of the US they've migrated to underground cabling and larger transformers. My neighborhood has that, and we have about 1 transformer every 4 houses or so. No idea how big the transformer is from a kVA rating, but pretty much every house has 240V/200A service, so they must be pretty large. The transformers themselves are approximately 3' x 3' x 3' and enclosed in a box at the front of certain yards.
This map references all transformers and distribution lines for the french network nationwide for terminal loops. These are open data:
Enedis is a the public operator.
"Poste" is the French Jargon for transformer. BT is for low voltage. HT is for anything >1000V.
Like you will see yourself, the density of transformer is of the order of 10x less than in the US/Japanese model.
I read this comment as implicitly assuming two phases to require less copper than three. In reality, the total copper cross-section needed to transfer power in a multi-phase system _decreases_ with increased number of independently wired phases (all else being equal).
> How many residential appliances benefit from three phase
Induction hobs, saunas, EV chargers, to name some.
> and is the benefit outweighed by the additional cost of more copper for the additional wires?
Additional cost? You don't run that many 3-phase circuits, so the cost is negligible, and your 110V circuits require substantially higher current than ours (meaning thicker wires) so if anything I'd guess the cost for wiring a US home is on average higher than a European home.
To fair comparison, it's 3 phase 400V vs single phase 200V. I agree Europe system is better but it's not worth to change with huge costs.
Modern heat pumps in Japan with inverter is just fine with 100V or 200V for home, even for cheaper coolers. 200V hear pump electrical water heater (with tank) too.
Most houses sign up only up to 6kW or 10kW electricity, so EV charger will become a problem for family that has multiple EVs, but they will be fine with slower charging at night in most cases.
It's pain that common 100V ovens works poorly. 100V Washer dryer works barely okay thanks to efficiency. I want more 200V home appliances, like 200V 3kW kettle!
I'm talking about appliances that benefit specifically from three phase because of the benefits of induction motor driving. Water heaters, ovens, EV chargers, and many other things specifically do not benefit from this. The only thing you get is power density by effective 400V output from 3-phase 240V.
Obviously 100V would be terrible for high power stuff. I'm not suggesting that. But, 240V split-phase is more than sufficient for the vast majority of residential appliances, including EV charging.
> Water heaters, ovens, EV chargers, and many other things specifically do not benefit from this. The only thing you get is power density by effective 400V output from 3-phase 240V.
They do too. You have lower current intensity, lower cable diameter, lower losses.
For EV charger it is even more relevant because anything inverter based has (theorically) a better efficiency in a three phases system.
The only drawback of three phase power is currently the cabling complexity. The home electrical panel need to be careful of the phases's balance.
I specifically was referencing any benefits from induction motor drive with 3 phase. Of course you get lower current when you run higher voltage and more phases. But, again, that isn't free. You're paying for extra conductors and insulation.
Regarding EVs... I would assume that depends on the design. No EV sold in north america is even capable of being charged off 3-phase AC anyways, so it would require quite the redesign.
In the house we're currently buying there's actually an old laundry spinner (?) in the cellar, hooked up to three-phase power. The electrician mentioned that those motors basically never broke down and were far more reliable than 230 V one-phase devices. However, other concerns, like being able to put the washing machine in your flat out how many such outlets you actually have, probably phased those devices out. I'm not sure I'd consider a three-phase outlet for the rewiring now. The stovetop of course gets that, and, if necessary one day, the wall box for EV charging, but there's not many appliances these days that need it.
Not sure the electricians comment is related specifically to the three-phase itself, or just to the general observation that three-phase motors are put in more industrial/commercial applications, where reliability is much more important. Pair that with residential use of commercial appliances tends to be very gentle on them (e.g., they don't get run 24/7, vs. a commercial place that would try to use them at every possible moment) and you have a recipe for a very reliable device.
I asked them whether it was specifically about that and they said yes. The appliance in question was a consumer item, just a tad older, not a repurposed industrial machine.
Well, here in UK nearly all residential properties have only a single phase supply - it can actually be really limiting nowadays. Some older properties are only wired for 60amp draw at 220V, meaning you can really only have an electric shower and an oven on at the same time and that's it, you've gone over the limit. People are finding it more and more as electric cars are getting popular and turns out fitting a 32amp(7.2kW) charger on a single phase 60 or even 80amp supply is sometimes not feasible depending on what else you have in your house already. Continental setup is far superior to what we have here for this reason.
> meaning you can really only have an electric shower and an oven on at the same time and that's it, you've gone over the limit
What's the deal with your electric showers anyway? Surely it's more efficient to heat in a central location and distribute both a cold and a hot water circuit through the building...
Probably talking out of my ass, it's just so weird and I haven't seen it anywhere other than in the UK.
Historically hot water in most houses in the UK came from a gravity fed tank in the attic. This means low pressure. If you wanted a high pressure shower, your options would be to replace the gravity fed system with a cold water pressure system (which can be expensive and might also involve disruptive relocation of pipe work) or to just fit a cold water fed power shower.
On-demand heating has the advantage that there is no thermal loss due to keeping a large amount of water (plus piping) hot 24 hrs a day.
Plus water is not wasted in waiting for hot water to arrive each time a tap is switched on.
Back in the days of Coal-fired power stations, people were encouraged to use storage hot water systems which were automatically switched on at night, so the the power stations could continue running because of the large base-load power demand.
However the modern Solar/wind generated power systems are the opposite, they much prefer loads which are only on during the daytime.
On-demand HWS can use heat-pump technology if required. Even tiny refrigerators use a heat pump. If they aren't widely used, it's because the savings are too small to warrant it.
Regarding solar HWS: The cost of heating panels, piping, and installation, has meant that they are fast disappearing from the market. It's better to add a few extra solar electric panels and use on-demand HWS, either with battery storage or via grid connect.
I've just been down this route with a new solar electric plant. I had originally assumed that Solar HWS would be included, but after doing the calcs, have abandoned the solar heating panels and instead opted for a few more solar electric panels plus extra Lithium batteries. It means I have a lot more storage that can used for many different purposes.
Refrigerators are similar to tank system, rather than on-demand hot water system. With smaller heat pump, tank is needed because it can't heat water immediately. Refrigerators have small heat pump so that's similar thing. Both should have good insulation.
Heat pump heater can be run when solar panel generates so much energy (energy price is low). That's a similar thing as batteries for energy use time shift.
You do usually, but with a gas combi boiler. Electric showers aren't that common in the UK either (23 years here and never seen one in person; but had never heard of them before moving here...), and usually a hack when putting a shower somewhere that didn't previously have plumbing.
Single-phase 16A? That's the standard? My tiny apartment homelab probably uses at least a third of that (I should measure its consumption actually...).
Said 50m² apartment has 16A triple-phase installed, but the breaker box is wired to be capable of safely drawing up to 63A triple-phase from the grid if I needed it.
Yep. You can obviously upgrade to 4.5 and 6 kW (still single phase, I think), or go three phase. Single house probably do that. But I'd be surprised if the apartments had more than 3 kW installed.
This results in a big payoff for efficiency, however: high efficiency AC and heat pumps for water go a long way in increasing how much you can do on so much little power.
I mean sure, but there are certain appliances(like kettles) which really can't get any more efficient, so if you want to boil some water......3kW overall limit for the entire apartment is seriously limiting. Like, if someone is boiling water and another person uses a hair dryer, it will blow fuses?
For three phase vs single face, the amount of copper doesn't go up since the current is shared across the additional conductors-- generally the amount of copper required is actually lower due to power factor improvements.
However, for low capacity hops the cost of additional insulation and extra copper needed to achieve ampacity (for worst case fault currents-- the cable must have higher capacity than the breaker so the breaker trips first and with 3ph you have three over-provisioned conductors instead of two) may make it worse off.
> ...the copper to run those is extremely expensive, on the order of hundreds of dollars. Adding an additional wire may add an additional hundred dollars or more...
Vs. checking a couple commodity pricing web sites - copper is currently ~$3.85 per pound.
I really doubt the motor of any "residential" HVAC unit is heavy enough for that "hundreds of dollars" to actually pan out...
I'm referring to the cost of the wiring, not raw copper stock price. Also, I mean the cost of the wire from the breaker panel to the HVAC unit. On average, I'd assume that the wire run is at least 50 feet. 100 feet wouldn't be unusual. 100 feet of single-wire 10 gauge THHN (enough to run most HVAC units here) would be ~$60. That also doesn't include any additional cost by upsizing certain things (conduit) that may add.
To note, as mentioned, copper is not the only cost here. You also need another pole to your breaker, which adds cost. Plus busbar upgrades. And more.
3 phases is cheaper than single line for delivering a houses power. You can get away with 3 smaller cables than the larger cables needed for 110V or 230V low voltage single phase at a particular amperage.
The cost of termination of 3 phases is insignificant compared to the cost of the rest of an electrical system in a modern home.
> How many residential appliances benefit from three phase, and is the benefit outweighed by the additional cost of more copper for the additional wires?
Three phase wiring is so ubiquitous here, there is nearly no additional cost.
You can't just say there's no cost because you don't see it. You don't have the option, so of course there's no way to tell price differentiation. I'm talking purely of raw material cost though. By adding a 3rd load conductor, you inherently add wiring cost and complexity, which should result in cost to the consumer.
It may be offset, as others point out, by power delivered being higher (and thus, wire gauge can go down) when running 3 phase... however that will largely depend on the load.
Most people have so few things in their house that would benefit from 3 phase that the cost isn't worth it. That extra wire isn't cheap, even if you downsize them all you still pay more. And as others have pointed out modern motors are (slowly) switching to using a VFD to generate 3 phase so there is even less need (in fact in industry a lot of equipment is switching to a VFD even though 3 phase is wired to the machine)
I have monitoring on all the phases on my house (in Sweden) and I can charge two electric cars, run the heating in winter, run the washer and drier and cook with two ovens a microwave and the induction hob at the same time and everything just works.
Things on three phase in my home: swimming pool, sauna, induction hob, electric car chargers, heating system and I have sockets to plug-in welding and other power hungry equipment. The rest is split on the phases. I can’t remember whether my solar system supplies on three phases or not but I think it does.
Yeah, but how many amps? What really matters is what your total available wattage is. In the US, 240v@200A (48KVA) is not uncommon. My 1979 house and every other one on the block has that, and that was assuming fossile fuel heat.
That can easily support all the things you listed and do it for a 2500 sq ft house, based on the overly conservative and outdated US NEC lead calculations.
You have it so they use it, but single phase will run it all just fine. The pool pump and welder can benefit from 3 phase, but for the pool pump the benefit is marginal. For the welder a modern inverter welder is better yet.
The pool pump on 3 phases seems slightly more efficient when I compared them last time. The pool is also being fitted with a heat pump inverter, which doesn’t need 3 phase.
> is the benefit outweighed by the additional cost of more copper for the additional wires?
don’t cheap out on wiring. a few years after you move homes, you find some new hobby: woodworking, CNC or 3d printing, restoring pinball/arcade machines, HiFi audio, hosting LAN parties or just a few beefy gaming or video editing rigs, hot tubs, _whatever_. you can’t predict it, but there’s a good chance it’ll need power, and once you pass 1500 W in one area of the home you’re gonna either be playing the “semi-permanent 50-ft extension cords bridging the under-utilized circuits to the over-utilized rooms” (and shuffling those around with every spring cleaning) or paying 4 figures to rip out the drywall and rewire shit. just pay that up front: it’s not worth the hassle and if you have a decent realtor you’ll recoup the bulk of the investment come sale time.
In many places (but not the US because of thermostat standards) HVAC systems are now typically inverter driven as well so that does remove some of the advantages of three-phase since any individual load is single-phase anyway.
Many HVAC systems in the US also use inverter compressors now. The efficient units (which includes most minisplits) are inverter. The efficiency requirements of the recent government subsidy program pretty much requires an inverter.
One example would be a cooktop and electric oven. I have one that connects to 3-phases. On the cooktop, the left and the right sides are each connected to their own phase. You can run both sides at 2,600 watts max at the same time. In the oven, there are 3 heaters: top, bottom, and one inside the fan; each connected to one of the phases. Together they can reach about 10,000 watts. The oven has a heat-up program that uses all 3 heaters to reach the temperature you've set.
Overall, it can heat things up more quickly than a typical gas or electric stove while being more efficient. And you can quickly change the temperature like with a gas stove.
> How many residential appliances benefit from three phase, and is the benefit outweighed by the additional cost of more copper for the additional wires?
due to the higher voltage in europe, conductors tend to be quite a bit thinner than in the US, to carry the same amount of energy. That being said, our electrical installations tend to be much beefier than most US residential, so a lot of copper is used. in Denmark for example standard for houses is to be fused at the roadside box for 3x~30A
In EU, there is another important aspect, that is: the fact that the suburbs are mostly composed by residential buildings with 2 or more floors, unlike the US.
It's really common for every building to have 3 phase 380V booster pumps, elevator motors, central heating systems, etc... .
> How many residential appliances benefit from three phase
I know of at least one, but I am ignorant of many other things and this just comes from my understanding of AC motors but: Any directly connected AC fan will have enormous benefits in terms of performance and efficiency with three phase.
Low current devices such as AC ceiling fans use so little current that the wire gauge is largely based on the minimum sizing for code standards. At least in the US, you can't put anything smaller than 14 gauge (AWG) in walls. Maybe in Europe they allow much smaller gauge, in which case maybe it makes sense... but usually there are minimum requirements for wiring since it becomes a structural issue (i.e., too thin of wire will break easily when pulled).
There is no benefit to performance or efficiency with a single-phase motor vs a three-phase motor.
Controlling the motor with a VFD is how you increase the efficiency and performance of a three-phase motor, simply being a three-phase motor provides no efficiency benefit other than you can use slightly smaller conductors to power the motor.
Why are large industrial motors three-phase? I almost always see large industry getting three-phase, which I assumed either gave more power or more efficiency.
It has nothing to do with efficiency (do the math on the conductor gauge and it all mostly cancels out) or power (idem) but the types of motors used (squirrel cage I believe).
The problem is getting the motor to start spinning. You cant start all motors on just one or two phases. And if a motor isn't spinning, it's essentially a short.
No, very large single-speed industrial motors are synchronous motors, not squirrel-cage (induction). These motors cannot start spinning on any number of phases: they can only run at the synchronous speed (which is dictated by the power line frequency and the number of poles in the motor). And it's not a short; it just doesn't run at all if you supply power to it; it only works once it's at the synchronous speed. These motors are used because they're the most efficient type of AC motor. Induction motors have "slip" of around 3% IIRC.
Basically what the sibling comment said, it’s easier to start a three-phase motor, and a three-phase motor will also run more smoothly as it is powered by 3 sine waves 120 degrees out of phase with each other which provides constant power; versus a single-phase motor being powered by a single sine wave that outputs no power at the middle of the sine wave with two power peaks, which doesn’t run as smoothly as three-phase power with no points of zero power output.
Brushless DC motors are always driven by inverters. They aren't usually sinusoidal inverters, and these things are more accurately called digital electronic pulse modulators, but they're often advertised as "inverter-controlled."
400V three phase is wired to all houses at least here in Finland. All 3 phases are wired to the electric box and then that splits phases to normal sockets and for lighting etc. Ovens use three phases and detached houses usually have separate 3-phase plugs outside for running eg. heavy construction tools, like cement mixer and such. Oh right and sauna stove also needs all 3 phases obviously.
Even apartments have that full 3-phases, but just for plugging in the oven and the sauna stove.
Its everywhere in Europe. I haven't seen nor heard about say a single oven not plugged into 400V. I've lived in 4 different countries in east & west, all the same. Even when traveling around a bit, I see those special plugs in convenient places, where you may expect to plug something powerful for some heavier work.
Anything high power, you go for this plug. I'd imagine car charging would also benefit from this but not personally in that market yet.
This HN thread is the first time I learned about 400 V to homes in Europe. My oven is 220 V. I just checked the manual. All my house is 220 V. I live in Italy.
Plugs are usually Shuko for high power appliances (washing machine) and two smaller pins for low power (phone chargers.)
By the way, Italy traditionally had a three pin in a line high power plug but more and more appliances are coming with Shuko plugs so wall socket are either bi-standard or just Shuko now.
The 400V is between phases. 230V is between a phase and ground. Ie, you get 3 wires (phases) of 230V from the 400V connection.
Btw, Europe standardized at 230/400V in the nineties. In Czechia we switched from 220V to 230V in 1993. Not sure when Italy did, but probably around the same time.
"Standardized". The allowable voltage for power is normally something like 6%. When they switched from the mis-mash of 220 and 240V to 230V, they specified the allowable voltage range was wide enough to encompass both of those, including the allowable voltage range for 240V. So largely it was just "Everything is 230V now, and try to make sure new stuff is actually 230V".
Yes. “Standardising” to 230V +/-10%, allows for 220/230/240V +/-6% (the previous standards used in different countries) to all coexist without actually changing any equipment.
The last transformer between houses and the grid is 440v three phase. As I understand it the distribution networks all look pretty much the same, it’s only the last mile that differs. And thus consumer electronics.
If you want to run a machine shop, it’s a pain but not impossible to get 440 three phase wired straight through to your business. But consumer “heavy” motors and induction stoves run on two phase 230V.
Currently probably biggest advantage is electric car charging. It is easy and cheap to add high power fast charger when there is already 3 phases available.
400V between phases so 230V per phase. Safety is provided by making plugs not expose contacts while half plugged. US plugs are really unsafe compared to plugs used in most of the Europe.
Inventor syndrome. Same thing with our cell phone networks and space ships. When you invent something you end up with the most “archaic” version, by definition. But it seems to still be working. American pragmatism says there’s better places to allocate resources.
No idea if you're from the US but this "weak infrastructure" has/is hosted/hosting nearly every important infrastructure that makes the online world go round and has been doing perfectly fine for decades.
I am in Australia and am in the process of having our home supply wired for three-phase 415v. Everything is heading down the path of electrification. Where previously we had gas central heating, cooking, and hot water, we are replacing those with electric HVAC (30amp circuit @ 240v, admittedly rarely driven that hard), electric instantaneous hot water (40 amp @ 240v), induction cooktop (32 amp), oven (15 amp), and also introducing a car charger (total approx 45 amps across the three phases).. it's likely at least the HVAC, cooktop/oven, car charger, and hot water could be on at or around the same time, which would result in more power draw than a standard single phase connection here (80a) could supply. It's not that it's needed all the time, but it's helpful to have the headroom a 3-phase supply can provide.
Yes, Americans invented populace relocation (and the abuses that come with it). Nice to know the Roman Empire had a time machine to pull a major component of their imperial edict from.
But let's pretend your warped view of history is reality...that happened 100 years earlier. If Europeans are so enlightened atop those tall horses, maybe don't do it again and 10x worse?
In addition, I wasn't referring to the Holocaust...but the entire continent's shared sick desire to kill themselves off for 10km of border movement or literal dreams of world conquest.
This wouldn't surprise me, but I can't find it. I'm seeing some authors drawing comparisons, but haven't found Hitler or his party actually mentioning Native Americans. There are explicit references to Turkey, with Hitler mentioning the Armenian Genocide (as justification for invading Poland) and calling Ataturk a "shining star," along with the Nazi papers obsessing over his nationalist policies.
Interesting thing I learned, horses actually originated in the Americas. Some of them migrated to Asia, then the ones in the Americas died out before human civilization, so only the Old World civs had them. When Europeans brought horses to the Americas, they were bringing them back.
Ok I'm going to make this even darker: The metric system sucks for non-scientific usage, especially using Celsius for room or weather temps. Idk why Europeans (and other continents) insist on using something with such low granularity and weird usable ranges. 0F = prob not going outside, 100F = close to highest temp you'll see all year, 56C = highest outdoor temperature ever on Earth. In the 70s (F) = warmish weather, in the 60s = coolish weather, in the 20s (C) = either cool or hot. Digital thermostats add 0.5 increments if you set them to C mode, lol. Meanwhile KPH is too granular, while 0-100MPH is all you need for cars outside of racing. Divisibility into meters etc is pointless, cause it's not like I need to compare a road trip length to the height of a person.
No surprise that basing your units on the physical properties of water doesn't give you very human-friendly results. Their only good unit is kilograms/grams. Edit: actually not even that.
A laptop that's a pound and a half is also very different.
But oh, if you're willing to say "and a half" you might as well be willing to say .7 kilo.
There's no real overall advantage, you just picked a couple very specific numbers. You can always pick very specific numbers to make any system look better/worse.
I don't think I can perceive a half-pound difference, but half increments are still nicer than needing the whole range of decimals. If I have to say 0.7 anything in everyday life, then it's not a good unit.
Speaking of which, there's nothing stopping us from using something like SI prefixes with customary units, for example kilofeet. We just don't need to.
> detached houses usually have separate 3-phase plugs outside for running eg. heavy construction tools, like cement mixer and such.
Is this sort of use common in Finland? It seems like kinda a waste of money and materials to install the infrastructure to allow everyone to run heavy construction equipment off their home's electrical supply.
I can't talk about Finland, but in Central Europe it's pretty common as there is a culture of house building.
In the US, a developer typically buys an entire neighborhood's worth of land and builds a bunch of houses there to sell to individuals.
Over here, the individuals will typically buy their own small plot of land and then have a house built there according to their specifications. You need to be able to run heavy construction equipment to do so.
Since you need three phase 380V for the sauna and the kitchen anyway, and probably for the ground or air heat pump too... it doesn't cost almost anything to run a cable from the electrical box and installing a three phase socket.
It is more efficient. Going from 4 wires to 5 is not a big deal if you then can have triple power. Or you can use thinner wires thus less material overall.
The split phase is two lives, neutral and ground. 3-phase is 3 lives, neutral and ground.
In Europe the wiring in the ground is always 3 phase, they just connect only 1 phase. You can upgrade to 3 phase for a fee and then a guy comes and switches it over. They don't need to open up the streets or anything like that to get you 3 phase power.
Houses in the UK are connected to a single phase, but a three phase supply is available if it's needed — the cable is in the street, though digging a new trench to connect to it is often costly.
Larger users are presumably connected with three phases by default — that primary school in the middle of the housing estate, the retirement home that has several lifts, not-tiny shops, the small block of flats etc.
It is. I remember when we had a power cut and when I went outside I could see that only a single phase had been lost - every third house had gone dark, the rest remaining lit.
In CA it's just a matter of checking a box, then they put a transformer on the PG&E pole to match your voltage reqs - the wire to your pole is $90. The transformer can run in the thousands probably up to 10k. Of course, if your area can't handle the voltage * amperage requested, they may deny it or ask for about 10k per new pole to install in the ground.
That said you just pay that once, after that you have your rate.
A lot of people have odd power requirements - but usually not residences. Farms typically get 400V for greenhouse fans, for example.
Haha, I can't get it at all here. It's not a matter of paying an absurd price that will get you a PhasePerfect for 10% of it. It's a matter of it just not being available at all.
Have you really asked? Generally it is possible if you pay, but expect to pay $100,000+ to get it. Most neighborhoods don't have the right wires to you pay paying for all new poles and wires to your neighborhood.
That said, a few cities/states don't allow 3 phase to residences in their building code. However most do allow it, and so it is just a matter of convincing the power company to run it.
I think most home shops use phase converters, either rotary phase converters or variable frequency drives. With those you can create a third phase to run machines that need it, although obviously you won't have as much power available to you.
And of course, an alternatives is to have a battery bank as well with inverters - which means you can get your amps - but only if you're not running 24/7. You'd have to let the grid (or solar) charge you up.
Far more common for 3-phase motor loads in residential areas (already an unusual requirement) is the point use of a rotary phase convertor or (more commonly now) variable frequency drive to run the 3-phase motor from the existing split-phase supply.
In the US, the amount of three phase electricians that will work at a Residential home and not charge you an arm and a leg for it is vanishingly low, almost certainly not worth it.
That's sort of a chicken-and-egg problem. If residential three-phase electricity were commonplace, electricians would all happily handle it at their standard rates, your air conditioners and refrigerators would all be running on it.
No? It clearly takes more training and has more liability since the consequences of a mistake are more serious. The average billable rate would inevitably be higher regardless.
Wait, there are special electricians for three-phase in the US, is this like an additional certification or are the normal ones scared of three phases?
Electricians specialize. Resi guys do residential and rarely to never handle 3 phase. I do commercial and light industrial because heavy industry isn't around here and I despise doing resi work. Three phase is usually run everywhere by the power co and a transformer (pole pig) converts to single phase near the residence.
Not sure if there's an additional certification, but it would not surprise me at all that an electrician here would not want to work on a home with an unusual setup that they're not particularly familiar with.
Maybe it's a little different for just a converter, but mine didn't have a problem installing a Phase Perfect and running a few three-phase outlets for it.
The answers and comments on [0] would seem to suggest that's not true.
Seems the power grid has the capability of delivering three phase power, but many (most?) homes in quite a few European countries don't actually have all three phases delivered.
> No matter how you put it, the US residential power grid is conceptionally lagging.
That's only the case if you believe the US is "missing out" on all that much with our split-phase setup. I don't think that's the case, really. Even for EV charging, using the 240V across the -120V and 120V lines is more or less fine. We've been doing the same thing with our electric stoves, water heaters, etc. for quite some time now.
Certainly there are some things you can do with 3-phase that aren't really feasible with split-phase, but I don't think most people living in the US care too much. It's true that those who do are probably upset about it, though!
Also consider that the US power system is trivially 3-phase! We just don't wire all those phases to homes, as we a) don't generally see the need to, b) chicken-and-egg problem suggests that most people wouldn't be able to use it anyway, since appliances made for the US wouldn't be able to take advantage of it.
We definitely had the wires for three phases coming into the house (Europe, NL) when we got a heat pump and induction cooking plate, the electricity company connected two additional phases in our utilities closet. I asked them, and the only thing they did was actually hooking it up.
It was also free (there was a small cost, but the government subsidizes it to encourage that people switch to heat pumps).
The answers and comments on [0] would seem to suggest that's not true.
Seems the power grid has the capability of delivering three phase power, but many (most?) homes in quite a few European countries don't actually have all three phases delivered.
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Really all modern residential connections in Europe are 400V three phase electric power
You see if they don’t have it delivered, it’s not a modern connection. Conundrum solved!
Long haul power transmission is almost always 3 phase AC in the US - it can be done using either 3 or 4 wires. It tends to better distribute loads and requires smaller conductors for the same power transmission level.
Split phase is almost always the last mile to residential customers as it’s simpler and easier to reason about (less likely to have severely unbalanced phases too) and requires fewer conductors.
400v 3-phase in a house is crazy to me. I was hit with 480v once (someone cut my lockout and turned the power on). That stuff will outright kill you unless someone else is around to help.
One of my favorite things about US residential power is that 120v is far less dangerous when homeowners (or worse, kids) accidentally do something they shouldn't.
You forget to take something crucial into account: the US's safety standards are laughable when it comes to electricity. The standard US plug is _begging_ for people to stuff things in it like say, knives, rarely if ever has an earth pin, has no shutters, is massively unsafe, the cable gauge is laughable, GFCI outlets are a miracle to find, and the building rules are... let's just say they're an invitation for house fires.
Most european houses have a single 400v outlet: right in your kitchen, for the oven (which means the oven is going to be right in front of it.) The likelihood of a child playing with it is close to nil. As for adults, the vast majority of people are taught to just flip the breaker and work on it if needed.
I promise you more people died of sticking metal into US outlets than from 400 volts.
> The standard US plug is _begging_ for people to stuff things in it like say, knives, rarely if ever has an earth pin, has no shutters, is massively unsafe, the cable gauge is laughable, GFCI outlets are a miracle to find, and the building rules are... let's just say they're an invitation for house fires.
Literally every single thing you've asserted is categorically false.
Earth pins have been required on outlets for nearly 50 years at this point. US outlets are also polarized, which Europlugs are not.
Shutters on outlets have been mandatory in residences and medical facilities for well over a decade.
The cable gauge is sized for the current and ambient temperature.
GFCI outlets are required nearly everywhere there is water, damp conditions (such as basements), and power tools used (such as garages and outdoors) because tools are most likely to have frayed and poorly repaired cords. Additionally all bedrooms and living spaces now require arc fault protection as a leading cause of fires is due to frayed lamp cords.
Europe still leads the world when it comes to smoking in bed as being a leading cause of house fires so I would not cast stones in glass houses.
They've been mandatory since 2008. (NEC Section 406.12).
Many people don't notice they exist. You have to examine the outlet fairly closely to notice them but certainly any new construction is all TR receptacles now (with the possible exception of the ones very far off the floor).
Most residences are more than fifteen years old, so people won’t notice changes. Also modern shuttered outlets are better than the first ones that were available, so you won’t even notice unless you look closely.
EU countries have their own history of terrible plugs and outlets, not that far back either. The 2 pin continental plug (when not shuttered, which old outlets aren’t) has all the same issues as the old US two prong plug - but twice the voltage!
Modern US outlets are usually shuttered, and 3 prong grounded outlets have been the required standard since about 1969. Which is over 50 years ago.
The Swiss and UK plugs and receptacles are awesome because they have plastic buffers in the plug's prongs and/or receptacle that make it hard to ever be able to touch live metal prongs in a plug that's between 0 and 100% plugged in. Schuko looks pretty safe too and that standard is from almost 100 years ago! I consider myself careful, but have had a metallic cover and a pen fall onto North American plugs that were partially exposed (thus shorting hot with neutral). Both times the outlet had tamper resistant shutters which did nothing to prevent ensuing fireworks.
Yes the UK plug design is the best I've seen. Mandatory 3rd pin to open the shutters, insulated prongs until they are well disconnected, and very solid fit. More often than not I see plugs half falling out of US sockets, with live and exposed terminals. Thankfully it is only 110v, but still a fire hazard
The mains issue I have with them is just how big they are.
Given how many things I have plugged in on or around my desk, I’d need power strips the size of a large dog to plug them all in UK style. Whereas US they all fit in the size of a very small cat.
I have fond memories of toddling around an under-construction room, picking up a screw and sticking it into a 220V outlet. Huge round holes, compared to narrow slits in the US.
Are you saying that US homes “rarely, if ever” have grounded receptacles? That’s not correct. All construction since the late 50s or early 60s require grounded receptacles.
I grew up in the US South, where everything was built post-air conditioning in the 70s, and I never saw an outlet without a ground until I went to Japan, where they still aren't standard. In Hawaii, outlets without a ground were more common, but if we're talking about the Mainland US, you really only see groundless outlets in very old buildings that for whatever reason have never been renovated.
Also GFCI is very common now. The vast majority of kitchens or bathrooms will have it. You'd need to find one that hasn't been renovated since the 90s, which definitely does happen, but it's becoming less common.
> Most european houses have a single 400v outlet: right in your kitchen, for the oven (which means the oven is going to be right in front of it.) The likelihood of a child playing with it is close to nil. As for adults, the vast majority of people are taught to just flip the breaker and work on it if needed.
Not to mention you normally can not electrocute yourself with 400V.
400V is between two phases, you never accidentally touch two phases.
When you touch a conductor you are between one phase and the ground, meaning in 230V.
Any time two phases are being run next to each other, there’s a risk of high voltage. That’s precisely what happened to me (two 277v lighting circuits).
Will you get an electric shock from sticking a fork across pins? I thought that the fork would short the curcuit. More probable scenario is that one can easy stick a finger between pins when plugging or unplugging a device.
That is why the voltage should be lowered to 70 Volts.
You can certainly get some fun, but modern outlets in modern homes will be GFCI and trip before much happens. If the GFCI doesn’t trip it means all current is going through the fork and none through you - the breaker will trip if the fork draws too much current otherwise it will just get hot.
When I first moved to China, I wondered what that “pop” was when I plugged things in and out. Turns out, most power outlets aren’t grounded there, and having lived in the states for most of my life, I never encountered that before.
Neither of these benefit from a 3-phase motor aside from not having to swap out $10 start/run capacitors, the conductors would be #8 for 3p and #6 for split phase.
You can easily power a three-phase motor on a split-phase service with a VFD.
You can get three-phase power in certain locations at a residence, but you pay a monthly connection charge and commercial rates.
It's actually an interesting unit: a ton of air conditioning is equal to the cooling that you get from melting a ton of ice per day. It has nothing to do with the weight of the air conditioner. Presumably this was useful in the olden days when businesses used ice for cooling and wanted to know what size of refrigeration unit they would need.
One ton of cooling is defined as 12,000 BTU/hour. The "real" value is 11966; apparently it's coincidental that it is so close to a round number. (One ton of refrigeration is 3517 watts in metric.)
No, the latent heat of fusion is 143.6 BTU/pound, not 144. It's just a coincidence that the energy to raise water one °F ÷ the energy to melt ice is almost 144.
Like many customary units, the ton (of cooling) is tied to historical accidents and I dare say is easier to imagine for a layperson; one could visualize the coolness rushing off a cubic-meter block of ice in a room, and how quickly it would melt depending on the temperature. 12000 BTUs, in the other hand, is not as intuitive (and the BTU itself is a customary unit, which is the amount of energy required to raise the temperature of one pound of water by one degree Fahrenheit).
And further, I guess there's just not much to be gained by going metric and saying "14 kilowatt AC unit" vs. "4-ton AC unit".
When picking an AC unit, running cost is not the primary concern: sizing is the primary concern. If you pick too large or small of a unit you will have issues. Too small won't be able to cool, too large generally won't be able to bring humidity down (outside of the newer inverter units that can run slower for longer).
Tons (or, BTUs of cooling) makes more sense, because the efficiency for a given cooling amount is variable.
For efficiency, we have efficiency ratings in the SEER/SEER2 ratings.
Good induction cookers and electric car chargers, heat pumps and things really do often require the high voltage for best function so this high voltage three-phase is also becoming standard for the energy transition.
I had to upgrade my electricity meter and switch box (even though as mentioned three-phase to the house is already standard) recently in order to accommodate planned environmental upgrades.
UK is in Europe and yet this isn't true here. Nearly all residential properties in this country are wired for single phase 220V. It's true on the continent though.
The split phase arrangement comes from Edison's DC systems. For large installations they found out that the losses were unacceptable and solved thet by running the lighting on 220V with sets of two 110V bulbs in series, usually combined with some somewhat funky wiring scheme in order to even more reduce the required wiring cross-section (it is somewhat reminiscent of later British ring mains construction and strikingly similar to various arrangements for powering long LED strips). This is also the reason why it is somewhat common for the US commercial lighting to use 220V.
Three phase for residental connection is pretty much a standard everywhere with 230/400V system. Only small flats and really small houses get single phase. This is because the 230/400V output of the larger distribution transformer is inherently threephase and this gets distributed to essentially all the points of connection and the only reason why there are single phase residental connection is that they are slightly cheaper (both in terms of fixed monthly payment for capacity and in terms of initial installation costs). While in US the input to the typical residental pole/pedestal mounted local distribution transformer is already single phase, so you cannot really get three phases without running additional wires to the substation (and probably also having you own dedicated distribution transformer) and thus in a residantal area you are simply stuck with split-phase.
> solved thet by running the lighting on 220V with sets of two 110V bulbs in series
A related tip is to build a "dim bulb tester" to help you diagnose short circuits on mains-powered equipment. I have a traditional incandescent lightbulb in a porcelain socket wired in series with an outlet (and a switch). A non-shorted load will tend to work pretty well as the cold/cool incandescent bulb is fairly low resistance in series with the load. A shorted load will light up the light bulb brightly but not trip any breakers, allowing the opportunity to do some troubleshooting on the bench.
I've also used this concept several times to find short circuits in house wiring. Put the dim bulb tester in series with the circuit that's shorted and then, using a non-contact voltage tester, find where the measurement on the NCVT changes. That's likely where your short is.
In building such a device, you're on your own liability-wise; please don't be dumb.
When I was a kid, I (ab)used this trick by wiring around a dozen 100 watt bulbs in parallel, between the line and a "probe". It was great fun for zapping whatever I wanted, writing stuff on metal, etc. In retrospect the biggest safety issue I missed was the light from the arc.
Another thing Americans miss out on - the "boost" function on modern induction stoves. Since the oven usually gets one phase and the cooking fields get two dedicated phases of the 400V lines, you can use "boost" to steal power from the other phase. Water boils even faster than in a tea kettle!
American induction cooktops also have boost functionality. All boost does is temporarily increases the power output usually at the expense of other elements. Power isn't "stolen" from other phases. Usually the reason why the cooktop cannot be in boost mode the entire time is cooling related.
What do you mean? Comparing a UK Bosch induction hob with a US one, they both seem to offer roughly 2.5kW of power in normal mode, and both offers a "boost" functionality that boosts the output temporarily to 3.6kW.
Stove outlets can handle 12kW in the US... So there's plenty of power to go around. Built in outlets can go even higher, with 240V/60A being somewhat common for larger appliances.
It is hard to find numbers, but combining phases is definitely how it works for some models, eg Miele PowerFlex uses "booster output of up to 7.4 kW" [0]. This is why you can only use it for one field.
> Stove outlets can handle 12kW
wasn't aware, in that case I was wrong, good for them
Sure would be nice to have some kind of hyper boost setting. There's a 3 phase connection, so why don't they use it? Time to heat that one pot of water with 11 kW.
Having 3 different inducting circuits would be hard to fit and make less even heating distribution. Also I think they would induct to each other. Also 11 kW could be dangerous with empty containers that is quite a bit of power. Like resistive heaters get red hot at lower power.
There are actually some stoves out there that can use two phases for one large pot, reaching 7.2kW. For example, Miele stoves with the "PowerFlex" feature do this (that is quite the big brain name given the context).
Since it is possible to do for two phases, why wouldn't it also work for 3? More power!
Bulbs normally burn out open, breaking the circuit. And in the unusual case that they don't, I would imagine the thin wires leading to the filament will melt, also breaking the circuit.
And if all else fails you your circuit breaker should flip.
If bulbs normally failed short, then you'd have circuit breaker's flipping a lot more often.
They can be a little spectacular when they fail short. My last incandescent (a bathroom light) did it a few weeks ago, exploding the glass of the bulb and popping the breaker for my downstairs circuit.
In electrical circuit terminology, "open" means "not connected" while "closed" means "connected/shorted".
That's different from direct translation of Chinese (and I think several European languages) where "open the light" means to turn it on (by closing the circuit, naturally).
I think it's most common English engineering usage (by far) to say that a burned out lamp fails open [circuit].
the neutral grounds both sides of the split phase and mainly serves to carry current when the load on each phase is unbalanced. when the neutral is cut off from ground all current has to be carried by the phase. if the loads are balanced, everything appears fine. when it is not you end up with a spooky electrical system. as now you have a series connection with a built in voltage divider. on one side the voltage will be too high on the other too low.
> I have heard a three phase residential connection is common in some parts of Germany, lucky bastards.
German here. Virtually all houses built after the 60s will have at least 3x63A @ 230V (L-N) / 400V (L1-L2/L2-L3/L3-L1) AC. Individual flats/apartments/studios from before the 90s will usually have a single phase 32-40A uplink, so in a 12-unit house you'll have four flats wired to L1, four to L2, and the last four to L3 to ensure even load across the phases. More recent builds that don't have gas stoves any more will have a 3x40 connection to allow for powerful electric stoves and ovens.
The US also uses a different primary network configuration, typically running a three-phase network as main primary with single phase primary laterals. The pole-mount single-phase transformers then turn this single-phase into split-phase LV for consumer use. One consequence of this is that adding three-phase to a property that doesn't have it already is really hard - you need to upgrade the LV service connection, the transformer, and the MV lateral (since the MV lateral is only a single phase). Compare that to the European system which has three-phase distribution transformers and then runs three-phase LV past every property. In some places like Germany, the standard is to provide three-phase to every property, in others like the UK, standard is single phase service connection but... it's easy to add three phase since the other two phases are only a few metres away, I understand the Dutch standard is to run all three phases to the property but only connect as a standard (you have to pay for the upgrade).
I think in both cases, for urban and suburban areas it is standard to run the MV feeder as a normally open ring so that in case of a fault in the primary, parts of the system can be run from the other end of the ring by remotely operated automatic breakers. What I don't know is whether US systems do that at the level of the main primary only or also on the laterals.
> The US uses a lot more smaller transformers, really one per street. while germany uses fewer larger transformers
I am from Spain and living in the US and something that was shocking to me about it is that here, at least where I lived, these last transformers are hanging from poles and every now and then I can hear an explosion and it is one of them blowing up.
I have no idea but, maybe being exposed like they are here in the US makes them more vulnerable to weather conditions and that makes them explode? Or maybe it simply is that in Spain they also explode but the fact of not being that close to residences makes it harder to hear it.
Transformer explosions are rare. Unless you can produce statistics saying otherwise it is safe to assume they happen as often in both countries (per something, the US obvious has far more transformers given larger population and area, and thus should have more total)
For some statistics, "U.S. electricity customers averaged seven hours of power interruptions in 2021." [1].
At first I couldn't find equivalent European statistics, until I changed my search to "minutes", which is how Europe measures outages. The EU average in 2010-2014 was just over 2 hours, and as low as 29 minutes in Germany, or 20 here in Denmark.
That isn't the relevant statist. We are talking about transformer explosions not all causes power outages. Transformers do explode, but not very often.
Most power outages are broken wires. According to my utility underground wires break more often than above ground, and when they break are a lot more expensive to fix. (They are trying to make a point so this might need some salt, though i don't care enough to look up what)
That was exactly my point, I have never heard that in Europe and I would say at least a dozen of them in US in a decade. Probably because there are more of them and exposed.
I am not criticizing the infrastructure but as European (and this is something others told me) it feels weird to see transformers hanging from poles and every now and then blowing up.
And I mentioned the weather because my experience is that it usually happens during storms, it might be lightnings or tree branches but that is what I have seen.
> but I will note it is a lot easier to keep spares and change out a small transformer.
In my neighborhood, about once a year there's a loud pop, or quiet bang, and a bunch of houses lose power. The electric company will fix it pretty quickly.
I think that it's performing selection pressure on the unlicensed squirrel electrician population.
Growing up in the sticks, I'm pretty sure there was an unlicensed trade school for squirrels in the area. Pretty much once a year, we'd need a replaced transformer from one of these unlicensed squirrel electricians. I never charted the timing of the year this would happen, but now I wonder if aligned with the start of a new class.
Here in the UK I think some of those unlicensed squirrel electricians are beginning to retain in fibre broadband installations. My neighbour was ‘disconnected’ last week.
The next time a friendly representative from the international brotherhood squirrel electrical (IBSE) union stops by to discuss joining their service protection plan, they should reconsider. "This a real nice connection you have here. It'd be shame if something were to happen to it"
I was a little surprised that my neighborhood must have some redundancy. A year or so ago a transformer on a pole two doors down from us popped, and our power actually didn't go out.
In Denmark, most homes have 3 phases of 240 volts, along with neutral. (and protective ground, of course)
More power in less copper. Most items do fine with 240 volts, but high-power items like ovens and electric cars can use two or three. Also, we have the CEE 5P plugs, which look awesome and allow you to draw a lot of juice from a single point.
How many residential devices actually ought to contain a three-phase motor running at fixed frequency? (And I mean now, in 2023, not in 1990.)
I can think of three, sort of:
1. A well pump, pumping from a high-producing well, into a tank or pond at the surface, where the pump is sized to efficiently pump somewhat less than the well’s production.
2. A pool or pond pump which, by some miracle, has been correctly sized for the system, and which, by some other miracle, is more appropriate in the application in question than an Intelliflo VSF or similar pump.
3. HVAC fans. But these are usually pretty small, and better systems usually use ECM motors.
I think that's overselling. I mean, sure, 3 phase is better for motors and you can get more power a little more efficiently and with less vibration to deal with in the mechanical design. And that's valuable. But come on, US workshop afficionados are doing just fine. No one is crying in their shop wishing for the blissful experience of a Danish band saw or whatever. It's better. It's not that much better.
What actually wins this fight is on the other side. A two-connector polarized NEMA 1-15 plug is a tiny, convenient, easy to use form factor that will still deliver 1400W. The experience of a normal consumer plugging in their normal junk in the US is just plain superior to the poor folks across the oceans charging their devices with BS1363 connectors that are almost bigger than the phones. And don't even get me started on Europlug.
BS1363 plugs are joyfully oversized, yes (and make excellent caltrops if dropped) but they are in other ways excellently engineered. Inherently polarised, fuses to protect the appliance wiring[0], socket shutters that open on the earth pin only to prevent vigorous insertion of metal by children, sleeved conductors to avoid shock when partially inserted, essentially unbendable...
Plus, I will fight anyone who suggests that 1400W is enough for a decent kettle ;-)
[0] Admittedly this was mostly included to offset the idiosyncrasies of final ring circuit wiring, but it's still better than just a big breaker.
Every time I try to charge something from a US socket the charger cable will frequently fall out of the socket due to poor design tolerances. Never an issue with EU sockets.
Sadly most outlets in the USA are installed by builders who buy these cheapest pieces of crap they can find.
Spend $5 or more an outlet and the plugs will work quite well.
(These kinds of things are what you should focus on if you build - materials are relatively small compared to labor and doubling your material cost on things like outlets can make a much nicer house. And if you want a UK outlet, you could get one wired up.)
BS1363 are comically oversized because they contain internal fuses, due in part to the strange ring main design, itself a vestige of WWII copper shortages.
I have all three of these and absolutely none of them contain (or will contain at any point) a three phase motor. All three of these use variable speed motors in my house. I suspect even more will moving forward as well. So honestly three phase is pointless as I just need "power" to drive the variable speed controller system. My hottub has fixed speed 220 pumps but its old. I suspect newer systems would be moving to variable speed as well.
I think your pretty spot on that most people do not need 3 phase, even in the limited cases you mentioned. =)
If you have a variable speed well pump, it is very likely to contain a three-phase motor. What it doesn’t have is direct wiring from the motor windings to incoming power. It likely has a variable-frequency drive consisting of an AC/DC converter (for which there would be a small but nonzero benefit if the supply were three-phase supply) and three inverter outputs connected to the windings. And hopefully either the VFD is in or very close to the motor (Grundfos will sell you a VFD/motor/pump combo like this) or has proper filtering to reduce high harmonics and properly shielded wiring to the motor.
> I have heard a three phase residential connection is common in some parts of Germany, lucky bastards.
Czech Republic switched to 3 phase 380V in 1919. I guess the transition DC -> 110V AC -> 3 phase ~400V went quick everywhere in the world, just in US they did not do the last step.
The cool thing is in Switzerland with the T15 / T25 plug you can use from a small 230V LN plug, 230V LNPE plug or a 3x400V 3LNPE plug. You see this often in workshops. I think this is unique in the world.[1]
Also the 3xT13, 3 plugs where everywhere else in the world is just one plug. [2]
I've worked at utilities with both systems. The UK system, which also has three phases to most every customer, is way better. And I'm an american power engineer.
By the way, the US nominal voltage is 120 volts. I don't know why everyone refers to 110 Volts.
You are correct about the last mile. Since single phase is distributed so often, the utility distribution engineer has a lot more work to balance things. In the UK and other networks, there is no single phase distribution.
When talking about the voltage of US residential service, and the devices that use it, 240 and 220, and 120 and 110 are functionally the same. The house theoretically has 240v and 120v power, but voltage may sag throughout the home's wiring, and some outlets will a real voltage reading lower than 240/120.
Every computer power supply I've seen in the last 10 years or so is basically rated for input as something like '100-250v, 50-60hz. That way they work on virtually any power grid anywhere in the world, it's just a matter of having the right female IEC to male <local whatever> power cable.
White paper I read 20-25 years ago described how those tend to work. Larger power supplies are required to be power factor corrected. They need to draw sinusoidal power in phase with the voltage. To do that they need a power factor correction front end. In the design the paper described what happens is 120VC gets rectified and stepped up to 240DC. Which then feeds a main DC/DC step down inverter.
I think the advantage of stepping up is the filter capacitors are cheaper for the higher voltage. I think because they handle half the current.
Cheaper and older power supplies typically have a switch to change the input voltage. DO NOT attempt to plug in and turn on a power supply set to 110v to a 240 volt socket.
Most power supplies do 100-240V so they can be used in multiple countries. You might be able to find cable to connect it to 240V plug, or could wire one up. But there would be no advantage to using 240V.
The only advantage for 240V is higher power. All desktop PSUs top out at 1800W because of the 120V 15A limit. There are server PSU that have higher power limits that would need to use 240V to reach the higher limit.
American circuits are designed to support a constant 15amp load, meaning you get 1500 ish watts. One 4090 overclocked and one high end Intel CPU overclocked, plus the cooling for all that, plus other parts, gets you uncomfortably close to that.
My hope is that this limit forces the computer industry to put at least one cycle into actual efficiency instead of just promising a node shrink will magically fix things, since we only have a few of those left really.
I shouldn't need to run a damn space heater to play a stupid video game. At this rate, you have to think about how much video game you plan to play in your electricity budget!
Contrast this to my house in NZ where each circuit is rated to 20 amps continuous and supplies a double socket rated to 10 amps continuous per socket at 230V (nominal). I can easily draw 2.3kW from a standard socket for 24 hours and have no issues.
This is really handy in a country that doesn’t believe in central heating…
Actually, electric heat and hot water in the US is frequently running off the 240 volt circuits too, as well as electric ranges, electric clothes dryers, pretty much anything that takes a lot of power. These items use various standards of plugs and receptacles and the circuits are usually rated to 30 amps (peak).
The US 120 volt, 15amp plugs are pretty much just for things you plug in and other light duty equipment. For anything serious, you can wire up a 120v20amp outlet or even the 240v 30amp circuit.
EDIT: I stand corrected by the comments below. Readers Ignore most of what I said on this comment. I was mistaken.
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You have some misunderstandings in your comment.
Unless it is a very old construction or a smaller home, houses in the US as well as most of americas are provided with one or more phases derived from the secondary of a step-down transformer in Y configuration (3-phase, 1-neutral => 4 wires).
So, for a small apartment, maybe you'll get a single phase wire plus the neutral, or more commonly 2-phase wires plus neutral, up to the full 3 phase wires plus neutral.
The phases are usually 220V between then and 120 between any individual phase and the neutral connector.
Europeans don't have this convenience because the step-down transformers give homes 3 phases in a delta configuration (so, 3 phase wires, no neutral wire), so, they only have the 220V between any two-phases.
Also, split and wall ar-conditioning systems are almost universally bi-polar with a capacitor, in Europe, Asia, or the Americas. As well as most refrigerators, freezers and other similar appliances. In the past we used to have driers that would be multi-polar, but it was never very common.
It is more usual to have tri-phase motors in bigger motors, like those used in central AC units. And HVAC systems in the US accordingly will usually require an upgrade if your home is not wired with 3-phase plus neutral, unless it is a small HVAC. Electrical vehicle charges also usually require 3-phase.
People are confusing what they have the electric outlets inside their homes with what gets from the street into the distribution panel in the house. Most power outlets inside a house are bi-polar connectors (so, in europe, they can only be 220 phase-to-phase, and in the US and most of the American continent, they can be either 220 phase-to-phase or 110 V phase-to-neutral. The third connector in a domestic outlet is usually the ground, not another phase or the neutral.
The three-phases are usually split between different circuits at home, trying to ensure that the load is somewhat evenly split, but at the outlets, you'll have either phase-phase, or phase-neutral, and this is the same in Europe or America, but the americans have the flexibility to have phase-neutral dipole with half the voltage that europeans don't have.
Regarding having smaller step down transformers close to homes instead of a single giant unit, we need to remember that keeping the low-tension wires short is more efficient, and this is achieved by having the transformers closer to consumers, instead of having a giant transformer distant from the consumers.
I am not an American, and I know that a lot of things in America could be more efficient, but power distribution to residences is probably not something were europe have an edge over the US.
> Unless it is a very old construction or a smaller home, houses in the US as well as most of americas are provided with multiple phases in Y configuration (3-phase, 4 wires, one neutral).
> So, for a small apartment, maybe you'll get a single phase wire plus the neutral, or more commonly 2-phase wires plus neutral, up to the full 3 phase wires plus neutral.
> The phases are usually 220V between then and 120 between any individual phase and the neutral connector.
I am an American - an electrical engineer in the Midwest - and I was on roofs last week after a tornado came through our town, working with the distribution panels. What you said is not correct. Homes get 240/120 nominal line voltage, or 220/110V at the load, 180 degrees out of phase, plus a neutral.
That is not the same as two phases plus the center conductor of 3-phase Y.
In industrial facilities, it's reasonably common 208V 3-phase in a Y configuration, with three wires each 120 degrees out of phase with each other. This is typically used for lighting circuits, because it's 120 phase to ground and can use commodity bulbs and ballasts. More commonly, machines will run off 480V 3-phase, which is 277 phase-to-ground.
Just for knowledge sake: you are correct that there are 4 wires:
1 - hot 1 120 v
2 - hot 2 120 v
3 - neutral
4 - ground
The hot 1 and 2 are 180 degrees out of phase with each other which is why 240v appliances can consider having those 2 wires (and at least the neutral) to be a 240v appliance.
And to be more pedantic about it, the ground is not provided not by the power company but the ground. I have 3 lines coming from the grid to my pole, line 1, 2 and the neutral that is created by the transformer. The ground comes from my ground - a long copper wire that goes a few feet down and back up. All ground connections in the (future) house will go there. Ground is also bonded with neutral at the box on my pole.
So your first statement is correct for apartments and condos. Typically 3 phase comes into the building then each unit gets 2 phases and a neutral ran to them. This actually works out to 208V phase to phase but phase to neutral is still 120v. Appliances like cooktops and ovens are definitely less power when ran off of 208v. For single family homes you only get a single phase, a center tapped transformer steps down the voltage to 240V leg to leg so coming into the house is two legs from the transformer and the center tap which is your neutral. Some really large houses sometimes get 3 phase but that is very rare. Usually large houses will just bump to 400 amp service.
US voltage is 120 V (240 V phase to phase), not 110 V. And while 115 V is within service tolerances specified by ANSI C84.1 (114 V to 126 V), that's not the nominal value.
It's a bit of a pet peeve of mine. We've been standardized on 240/120 since 1967, and still many people insist on saying 110 and 220. It hasn't been 110V since well before 1967, either -- it was increasing over time before they locked it at 120.
Its been 120VAC in the vast majority of the US since quite some time like the 1940's - 1960's.'
A minority are still 115-120VAC but very few still at 110VAC or even 110VDC.
But 110V line voltage is still too common of a misconception still lingering overseas.
This can be seen in some power transformers which are built overseas with multiple primary windings intended for international use. Often these will step-up or step-down the incoming line voltage to the working level correctly using the 240V primary when 230-240V is actually powering the transformer through that winding. But when used in the USA with the 110V primary, the transformer powers the working circuit with almost 10 percent higher voltage than the engineers thought they were going to get.
Thanks, I'm in canada and I know we're 120, I was wondering if there was some reason the US was different and I'd just never heard about it. Iirc Japan, at least part of it, may actually be 110.
It's really annoying as Japan has lots of wonderful vintage secondhand synthesizers for sale, but being domestic market models they often have non-switching power supplies that require 100 V.
Speaking of Japan and frequency differences, one funny indirect consequence of the power differences is the video game Super Smash Bros Melee having separate NTSC and PAL versions, one at 60Hz and another at 50Hz, and consequently running at 60fps or 50fps (unless you override this at start). For good players, 50fps changed the game a lot, so they'd always use NTSC or override to 60. But PAL Melee also had other gameplay changes.
A lot of games on the Mega Drive / Genesis didn't properly adjust their speed for PAL/NTSC, for example Sonic 1. They'd just run slower/faster according to VDP clock.
All video games and consoles had separate NTSC and PAL versions until relatively recently. PAL, which is 50Hz was/is used in Europe most of the world except a handful of countries including USA and Japan.
Japan standardized on NTSC/60Hz well before the video game era, for both the 50Hz and 60Hz mains power regions. The frequency is decoupled from mains power frequency even though it was historically based on American 60Hz power.
This is partially done to compensate for terrible wiring. Lots of people are fond of using small wires and going long distances leading to a lot of voltage drop. They often send 125v or so from the transformer which is 123-124 at the panel, 120 v or so at the receptacle, and >100v after someone decides to run something on a few hundred feet of #18 extension cord.
It's about looking at supply vs demand. Electrical devices are often labeled by the minimum voltage they require to operate. 110 V is commonly used because the device can operate reliably on a 120 V distribution system.
Power supplies are rated for 100V because that's the voltage in Japan. Though the tolerance would probably be useful for running a really long US extension cord.
My old computer started burning in some internal cabling about 30 years ago. Turns out our power wasn't 230 V when the power company came and set up a machine to make a graph. Some times of the day it could be much lower and that made my ancient atari converted to a towerbox to burn the cable to the harddrive on booting.
Laptops and other electronics are often the same between North America and europe, just with a different plug, thus the wide tolerance. For anything with a motor or coil this probably won't work
I have a question for you as a Brit. I live in an Asian household (my wife is Asian). We have a hot water boiler, as most Asian households do. It keeps 4L of water at "tea" temperature at all times (after boiling it).
When we want tea, we just fill up the cup with the already boiled and ready water. It's super efficient because it's super insulated so it barely takes any energy to keep it hot after it's been boiled.
Why don't Brits (and other tea drinking cultures in Europe) do this?
I'm not sure how much difference this makes, but when I use the hot water boiler at work, the tea definitely tastes slightly off compared to using a kettle at home. But it's also possible the hot water boiler at work is not producing hot enough water.
Ahmad and Impra are both several cuts above Twinings, not expensive (especially as bulk loose-leaf) and can be found in standard grocery stores, or ordered online.
If you've a specialty tea shop nearby, that's all but certainly better, though it can be pricey.
You'll find there's a whole new world out there, and may regret discovering a taste for real whole-leaf teas.
Greens, whites, blacks, fermented, oolongs, darjeelings, matcha, gunpowder, pu'er, etc.
There are also herbal teas, such as rooibos, not made from sinchilla (tea plant), but also tasty.
Best is to buy a bag of loose tea from a tea shop. The leaves are whole, it's not powder. It's usually not hard to find, but they don't sell it at most supermarkets.
An Asian style water boiler maintains the temp just below boiling, so there isn’t any reboiling throughout the day. Think of it as a water boiling thermos.
You’re meant to replace the water daily. Not sure how many follow that guideline.
ETA: Only the so-called “hybrid” models have vacuum insulation. It’s worth the extra charge.
But as it cools the gasses reintegrate. So I'm not sure the science backs this up. Water at the same temp should have the same amount of dissolved gas regardless of how it got to that temp (given enough time for the gas to reintegrate).
I think you're incorrectly discounting that time aspect. If you leave a glass of tap water sitting out, eventually there will be a bunch of bubbles clinging to the sides of the glass. This doesn't happen immediately, but rather over many hours. Similarly, I would think that boiling water won't reach its gas equilibrium during the course of making tea, but hot water sitting around waiting to be used will.
I agree with this. I develop my own film and the way I manage water is to boil it, put it into sealed bottles, and store those in the fridge. This avoids bubbles more readily than just using tap water (which is over 20C in the summer anyway, which is why I do the refrigeration thing). No, I don't have an aerator on my tap either. Obviously that introduces a lot of bubbles.
Nearly all tea advice is ideology and superstition, explicitly because most people like different things about tea. There cannot be a right answer for such a personal preference.
>Nearly all tea advice is ideology and superstition, explicitly because most people like different things about tea.
That's BS. It's true: people do have different tastes and preferences, so opinions are just that. But it's not "superstition": different brands/blends of tea really do taste different, many times remarkably so. It's just like a McDonald's burger vs. a burger from a high-end restaurant. One of course isn't objectively better than the other (from a taste standpoint; I'm ignoring nutrition here), since it's a matter of opinion, but you will find that significant groups of people who like a particular food enough to have tried different varieties will usually form similar opinions, or at least sort themselves into different camps.
"Superstition" implies that the differences people taste are not real, and this is quite simply false. The differences are real; it's up to you which one you like better. More expensive doesn't always mean better-tasting.
These use a tank to keep a few cups of water hot at all times. The instant part is the delivery of it, not the heating. So this does not satisfy the Twinings comment you are replying to.
it doesn't. the faucet of these types of tanks is just a pipe opening and has laminar flow. it doesn't exit the normal sink faucet (which will have an aerator).
The hot urn cannot be more efficient than boiling the correct amount of water each time.
The limiting factor is the specific heat capacity of water. If daily consumption is 2l, you have to put in the joules to raise 2l to boiling, either way. If you have heat losses during the day, there's your inefficiency.
How many people are boiling the correct amount each time though? I fill my jug up all the way and then keep reboiling which seems less efficient as the boiled water keeps cooling down.
Some do. It's become a popular addition to a middle class kitchen. All offices have them.
As to why Asian households have it and we don't, I think it's simply that we have been boiling water in kettles since the stoves ran on coal, and the electric kettle is just an upgrade of that same old system
Not to mention the age of our housing stock. The Asian households you refer to, when were their homes built? I'm guessing much more recently, comparatively speaking.
Why is the age of the housing stock relevant here? An Japanese-style water boiler is an add-on kitchen appliance, like the Instapot or an air-fryer, so,
cultural differences aside, you'd expect similar adoption rates. Given that we haven't, there must be some cultural component as to why.
Some people have instant boiling water taps with tanks, they're not unknown but rare and becoming increasingly less so. I think this is because a) they're relatively new here and b) last time I looked they cost about £1k plus fitting.
The Japanese water boilers look like they cost £200ish (vs £15 for a kettle) and are bulkier than a kettle. They will save practically no time - kettles boil fast here and while they're boiling it gives you time to put the tea in and any other preparations.
It just occurred to me that Japan also uses 120V (actually I think they use 100V), so it may be just a matter of speed. You can boil water a lot quicker with your 240V outlets than we can with our 100-120V.
You're not taking the amps into account. Voltage without the amps on the circuit breaker is pretty useless. Quickly Googling indicates that a standard residential circuit breaker in Japan is 30A (3000 watt max), meaning you'd get more power than you would in the US with 120v / 15A (1800 watt max), and much less than where I live in Germany with 230v / 16A (3680 watt max).
>You're not taking the amps into account. Voltage without the amps on the circuit breaker is pretty useless. Quickly Googling indicates that a standard residential circuit breaker in Japan is 30A
Sorry, that's wrong. The breakers on my 100V outlets here in Tokyo are 15A IIRC (I'm not home at the moment). 30A sounds like an air conditioning circuit. 30A on a regular outlet would require huge wires; they're not going to wire a whole apartment with that stuff.
I actually have a kettle here, bought in Japan. It's rated at 900W. It's OK for boiling a single cup of water, but it's definitely not quick. Faster than the microwave though: microwaves here are 500W or 600W (frequently selectable), and the high-end ones go up to 900W. All this should tell you something about the amp capacity of the kitchen outlets here.
900W is how much my kettle is rated for, which means it actually draws 900W of power (which is about 9A at 100V).
For the microwave, 900W is the power transmitted to the food, not the power drawn from the outlet. All microwaves are rated this way. But microwaves are not particularly efficient; just guessing, I'd guess that a typical 1200W American microwave draws around 1500-1600W, and certainly no more than 1800W since that's the max the outlet can provide. So my microwave at the 900W setting probably draws a bare minimum of 1100W (11A at 100V).
And that's a fancy microwave; the typical microwaves here are all 500/600W. I think the most powerful one I've ever seen in a store was 1000W, so that's probably the highest power rating that can safely run on typical kitchen circuits here in reasonably modern buildings.
Age matters because in many cases the house was built with some expectations, and something else won't work at all. In the 1950s your house got a total of 4 circuits, which was enough for clocks and lights, one fridge, and a kitchen mixer (an electric range was an option and added circuits). Of course TVs arrived in the 1950s (they existed before then but were not common) and started blowing power budgets. As people started using more electric new houses got upgraded to handle those loads, but many older houses have not been updated as it is expensive (major remodel as you need to tear down walls).
Of course the above is standard, not everyone takes the standard. However it is unusual to take something else.
Builders (read electric codes) build for what is common uses. If everyone wants an something that uses a lot of power the wires will be made to handle that in new houses. However if you want that same thing in an older house you may discover that the rewiring needed makes it not worth it and so you look for an alternate.
I'm not sure that's exactly true in this context. At least, I've never been in the house in the UK where the electrics in the kitchen couldn't handle a kettle, and a water boiler for hot drinks isn't likely to use more.
What is tea temperature for you? As I understand it black tea which Brits drink should be made with water at close to boiling (100 C) while green tea should be made with water at 80 C.
My pet peeve in the US is ordering a cup of tea and getting a cup of cooling water and a teabag by the side. Fine for herbal or green tea but terrible for black tea.
My boiler lets me set the hold temp at 208f(97.8C), 195F(90.5C), and 175F(79.4C). So basically you can do all the different "ideal" temps depending on which tea you make the most.
We keep it at 195 since we don't make black teas, and then we can let it cool down to whichever tea we want or just mix it with some filtered cold to get it to temp.
At least in the German-speaking market there exist said solutions, but they are not very common (yet?). I believe keeping 4L at near boiling temperature is still less efficient than individually heating and it takes less than a minute with 3kW.
The water stays way above the temp for legionella. And the water is still pretty fresh, it ends up getting replaced every other day or so in winter. And in summer we just replace it once in a while anyway.
Also it will reboil after a certain amount of time.
Has anyone ever made a battery-powered kettle with significantly higher power than can be pulled from a wall outlet? Modern lithium batteries can deliver many kilowatts of power, and given that the total energy needed to boil the water is basically fixed, the battery size requirements might be pretty reasonable. I wouldn't be surprised if boiling water in 15s is possible even on a 120v American outlet.
At 3.6V and 45A, each battery should output 162 watts. Rounding to 150 watts, we'd need 20 of them to make 3 kilowatts. So $100 worth of batteries.
=-=-=
Question #2: How long will they last? Long enough to boil water?
At the 45-amp discharge rate and with 4.2 amp-hour capacity, it should take 4.2/45 hours = 6 or 7 minutes to discharge them.
By my math, it takes 335 kilojoules to heat a liter of water from 20°C to 100°C. A 3 kilowatt kettle should be able to do it in 335/3 = 112 seconds.
So the batteries should be able to boil water around 3 times before discharged.
=-=-=
Those calculations are for running on battery alone. Since you can get 1500W out of an American 120V outlet, you could make a kettle that draws 1500W from the wall and boosts it with 1500W of battery power. (I'd use two heating elements.) Then you only need $50 of batteries.
The kettle is going to be a bit heavy, though. The batteries are 70g each, so 20 of them is 1.4 kg. Also, I don't know much batteries heat up when cranking out 45 amps, but I bet the answer is a lot, and you may need active cooling and/or thermal shutoff.
Put the batteries and controller in the base, have the jug lift off from the electrical connectors to the heating elements, the jug is therefore light and convenient.
It would be better to have a box that converts 2 NEMA 5-15 120v plugs to one 6-15 240V plug.
I've seen such a box for sale, I think for the RV market. You plug into both phases of the 120/240V split phase and get a dryer plug at a lower amperage.
Now I realize that what I really want to build is a kettle with two 3kW heating elements. On a UK ring main, I can plug the two elements into two neighbouring sockets and still have headroom before I blow the breaker. I can cut my time-to-tea from 45 seconds to 22 seconds!
It's certainly possible; whether it makes any economic sense at all is a different matter. I can't imagine much of a market for a device like this. Basically you're proposing a relatively complicated device (compared to a simple tea kettle, though modern ones have a handy auto-shut-off feature) for the sole purpose of boiling water a little faster. Americans aren't big tea drinkers in the first place, so it's hard to imagine many would pay 5x-10x as much (guessing) for a fancy battery-boosted tea kettle just to boil water a little faster. I suppose it's possible though; Li-ion batteries are pretty commonplace these days.
I think it's certainly possible. FWIW car batteries can often support 1000A especially those for large diesel engines. They aren't meant for continuously loads or deep cycles though. Marine batteries may be able to overcome this.
It's probably the most remarkable difference. It's interesting how houses are wired for 10-20A of current everywhere, regardless of voltage. You'd assume that since European houses are mostly wired for 16A then US houses would be wired for 32A (or the other way around, if you know US houses wired for 15A, you would assume the European wires for 8A). But curiously that's not the case.
Ignoring the UK with their 13A/30A rings for a moment, since their wiring is unique.
Largely this is resolved by US houses having a lot more circuits. My bathroom has a dedicated 20 amp (2.4 kW) circuit for the outlets and a separate 15 amp (1.8 kW) circuit for the lights. Every bedroom in my house has its own 15 amp breaker. The kitchen has 3 20 amp breakers for different wall outlets, a 15 amp breaker for the lights, then a 30 amp 240v (7.2 kW) breaker for the cooktop, and a 20 amp 240v (4.8 kW) breaker for the oven.
For the a typical US house the standard feed into the house is 200 amps at 240v. So 48kW of power coming in we just segment it down a lot more.
It starts to become annoying when you have a home office for 2 people though. 2 PCs + 4 monitors and some random things in a room can start approaching the wattage limit. Especially given that I think it's not too common to have one circuit per room (anecdata: my house has one circuit for all outlets per story; not counting bathroom and kitchen which I believe are mandated by building code to be separate).
Lots of smaller (kw) circuits is safer than a few very large circuits. The NEC in the US actually stipulates that you must use different receptacle styles for higher ampacities specifically because it is less dangerous. If you run a small appliance on a 30-40amp circuit, you run the risk of that seemingly safe appliance pulling the full 40+ amps required to trip the breaker
Not sure if I understand - can you clarify? Did you mean that a normally safe 1.5kW appliance runs the risk of cooking itself if it's connected to a 40amp circuit? If yes, then sure, that makes sense.
> Lots of smaller (kw) circuits is safer than a few very large circuits.
Not fully convinced about the safety aspect but it definitely feels more convenient (can selectively turn rooms off if you need to work on something) - if I'm ever opening the walls, I'm going to switch to that approach. At the very least, I want to have a dedicated 20amp circuit in the home office...
Largely yes a 1.5 kW device (a 12.5 amp space heater for example) is less safe on a 40 amp circuit. Since if it fail pulling more load than designed but not truly shorted the breaker may not trip. But if you put that space heater on a 15 amp circuit it would most likely trip the breaker. As other commenters have said the UK addresses that risk with fuses in the plug.
Also I recently redid my kitchen and I added an additional 20 amp circuit just for the kitchen island outlets and it has been super nice.
Are safety concerns alleviated here by GFCI breakers? In what cases could this appliance pull more amps than it was designed for? I know it's not required for circuits outside kitchen and bathroom, but I was thinking about just replacing all the breakers with combined GFCI/AFCI ones (especially given that my circuits are so old that there's no ground on them, in which case code I believe mandates that the outlets are GFCI-protected and labeled as "no ground").
So the risk would be reduced. Since if the failure causes a electricity to travel anywhere other than the neutral it will cause the gfci to trip. A scenario where a device would pull more power would be a short developing in a heating element reducing its resistance. So it would just pull more power but all of the power is still going to the neutral and wouldn't trip the GFCI.
Also with replacing all your breakers it can increase safety. But first the breakers are not cheap. Second it can lead to a lot of nuisance trips, albeit that is better than it used to be with modern breakers.
Yeah your AFCI in theory is supposed to help reduce fire risk. Since failures like that cause arcing. But yeah it will be around $60-$80 per breaker, but there is definitely cheaper than ripping open walls to re-run wires.
GFCI is not a magic “make everything perfectly safe” - you could electrocute yourself to very dead without tripping a GFCI if all the power went down the main wires and none went to ground.
Britain solves this with fuses inside appliance plugs.
The continental European system doesn't really solve it, as far as I know, so you have thicker wires on low power appliances than you would in the USA.
The US also has fused plugs but their are not widely used for some reason. I see them mostly on Christmas lights, but I have also seen it on some small home electronics like a window fan and air purifier.
Yeah sadly having separate circuits for each room is not required by the NEC to the best of my knowledge (and might be overkill depending on the situation). Usually though best practice is to have a separate circuit though for each bedroom. Depending on how your outlets are wired it might be possible to split them off onto separate breakers relatively easily though.
32A capable wiring is much more expensive. And if we are being honest, the number of modern appliances that need more than 1800W is very small outside of the kitchen. If it were a common problem people would be installing 6-20 receptacles, but that's pretty rare. I have exactly one, and it's in the garage.
Resistive losses are related to current (I^2 R), so you need thicker wires to deliver the same power at a lower voltage. I guess it was decided that it wasn't worth the expense.
Sure, obviously. But you'd expect power requirements to be more or less the same, and the ideal wire diameter to be dependent on voltage. But instead what happened is that the wire diameter is more or less constant, and Europe just uses more powerful electrical devices.
> Europe just uses more powerful electrical devices
Aside from kettles? I guess maybe some people have electric heaters? What else pulls enough power that the extra voltage will matter? Vacuums maybe, but no, those are limited to 1600W.
- Irons are commonly 2000-3200W (3200W is 14.5A at 220V)
- Portable Induction Stovetops are 3000W
- Deep Fryers are 2000-3000W
- Hair Dryers are 2000-2500W
And of course some things are connected via 3-phase 400V (3 220V phases, because of the 120° phase offset that's 400V between any two phases)
- actual oven + stovetop combinations, about 7000W for the stovetop, plus 1000W for the oven
- many tankless water heaters, 5000W-24000W seems common
The most impactful in day-to-day use are probably kettles and hair dryers, but with stovetops and water heaters there's probably a big difference in the prevalence in gas vs electrical, and tankless vs boiler simply due to wiring.
That's a good list, thanks. I'd be interested to know what the experience is like between a 120V hair dryer and a 240V model. I don't have enough hair to worry about such things, but my wife does, and it seems like her hair dryer gets hot enough that she usually turns it down a bit anyway.
The 'industrial' level appliances are probably less of an issue, because the wiring run is limited and you can customize it however you need to. I could go down and buy a 36kW electric tankless water heater today and wire it up without any difficulty. Though it would probably be worth upgrading my 200A panel in that case.
Ranges sound like they're probably pretty similar. Typical modern electric ranges in the US are about 10kW.
Three phases would be handy for reducing the cost of wiring, though. Cost me $1500 USD just for the wire when I ran four new circuits last year. Couple of them were 50A, which is partly why it was so expensive, but mostly it's just that copper is $$$. Any bigger than 60A and I'd switch to aluminum.
I don't have first-hand experience with the difference in hair dryers either, but I imagine it's mostly air velocity? With more power you can turn more air scalding hot, meaning you can offer higher fan speeds without compromising temperature.
If you increase Ampere you must increase the width of the cable, or it will overheat. If you increase Voltage you must increase the insulation around the cable.
As an American, I have a faucet at my kitchen sink that will give me water at 195F. That takes care of nearly all my needs for truly hot water. When I do need the last few degrees to get a roiling boil, my induction cooktop has a 3700W burner that will do it in a hurry.
> As an American, I have a faucet at my kitchen sink that will give me water at 195F.
The building code for the province of Ontario (Canada) states that delivered water cannot be higher than 49C (120F); §7.6.5.1. Maximum Temperature of Hot Water:
No. The law you quoted limits the maximum temperature of hot water supplied by fittings to fixtures.
It says nothing about fixtures that increase the temperature of water and dispense it, and does not limit the temperature of dispensed water. Instant hot taps are both legal and commonplace in Canada.
We have the same. The system has a high-end water filter which then exits into a split, one outlet of which goes to a room-temp tap and the other into the heater, so we have both filtered "cold" and hot water.
It's just one tap at that sink, clearly identified, in addition to the regular hot & cold water taps. I don't run my main hot water tank at 195F, that would be dumb.
Yep, I have a separate tap at the kitchen sink which is connected to a small (about 3 liters IIRC) tank underneath. I have it set to 195F, though it can be set as high as 210F. There is a receptacle in the cupboard under the sink where it plugs in.
To be clear, in the US the "instant hot" tap (when present) is separate from the main adjustable-temperature faucet. It's normally off to the side and visually distinct. It's usually much smaller and provides a limited amount of water from a pre-heated tank under the sink.
Zero. The 195F tap is not the same one you use for normal hot & cold water. The normal hot water in our house is set to 140F (we do not have any small children or elderly, if we did I might dial it down to 120F).
Now that I have a 5kw induction cooktop I can boil water incredibly fast. However I’m not sure it’s that useful since it’s not like I’m standing there watching it, so whether it’s 1 min or 5 min doesn’t matter.
I have a really old infrared range that takes 20+ minutes to boil a pot of water. Believe me when it takes that long it does matter. (it is on the list to replace, but there are higher priorities in this house to fix first, and only limited budget)
If you use an induction hob, a classic stovetop kettle (the kind that whistles!) will allow you to boil water quickly. The large ring on my last hob was 3kw.
I have a temperature controllable "kettle" (tank) under my sink connected to a tap and I get water at 195F. I agree on the convenience. They are pretty common.
Nitpick: a cooktop is just the burners, a range is an appliance with burners and an oven. It's relatively common on newer houses to separate them. E.g. I have a 36 inch induction cooktop and a completely separate double wall oven in another area of the kitchen.
AFAIK stovetop is also sometimes used when people mean cooktop, though in my area it's more often a casual reference to the burners of a range. I'm sure that convention varies wildly across the country.
The power companies know this, and time their cutovers from Europe with the end of Eastendets, which is when people turn on their kettle for a cup of tea before making dinner.
(I’m not sure if that’s still a good hint, but it certainly was ten or so years ago.)
Less important now. Back when 17 million would tune in to watch Coronation Street 3 times a week it was a much bigger thing. It's rare to get half that for legacy live TV outside of specific major broadcasts (The Euro 2020 final pulled in 30 million) -- the 10th most watched show of 2022 only got 8 million and the soaps are lucky to get 6 - inlcuding those watching time-shifted.
I would like to see a US electric range with Schuko outlets and 16A GFCI breakers on the side, but that probably violates too many electrical codes.
Schuko makes the most sense because it's unpolarized, so appliances don't expect a neutral leg. You still have the 50/60 Hz problem, but something like a kettle probably won't care.
Or there could be a countertop "Schuko dongle" that attaches to the screw terminals on the back of an existing range, if it weren't for those meddling codes...
Though in practice, the key to boiling fast is to use less water. A 1500W kettle with 500 mL minimum fill is totally reasonable for cup of coffee/tea.
I have 20 amp sockets in my kitchen (as all newly built housing has, really) but there are no 20 amp kettles on the market. I wish I could get that extra 600 watts or power :(
No it's not. It's just against code if they use a NEMA 5-15 outlet. If GP used NEMA 5-20 outlets and the appliance used a 5-20 plug, then there's no issue.
Many commercial appliances use 5-20 plugs. Also, lots of commercial cleaning equipment seems to use 5-20, which is why you see businesses tend to only use 5-20 outlets.
I'm not aware of any kettles that use 5-20 plugs but I bet they exist somewhere.
IIRC NEC requires 20 amp circuits for the kitchen. However the only time I've seen a 5-20R in a residential kitchen is after the electrician got done with mine (he insisted code required the 20 amp receptacles).
It's not required, but it is allowed. And, the only thing you need to do is swap a 5-15 for a 5-20. No other work needs to be done and it's all compliant.
The circuit rating is 80% of nominal for continuous loads - runtimes of 3 hours or more - according to NEC in the US. Not sure what you mean by “regular appliance”; there is no such definition by code.
A kettle is fine at a full circuit load for under 3 hours.
It's not, and for laymen "continuous load" has a specific meaning in this context. It means something that runs for 3+ hours continuously, without a break.
Well they can be, until they boil dry, and the thermal cut out kicks in.
Prior to the late 70s / early 80s so called "automatic kettles" were not necessarily all that common in the UK, and one had to manually switch them off.
I certainly recall a time or two with a kitchen full of steam due to forgetting about putting the kettle on.
There are regional differences that are probably causing some confusion. In the US, breakers have a nameplate rating 25% higher than their continuous load capacity. Go to Australia, for example, and the identical breaker will have a nameplate rating 80% of what it would in the US.
So you can run indefinitely at the nameplate rating in Australia, but only 3 hours in the US. And the startup current (inrush) can be much higher than the rating. Most breakers are thermo-magnetic. The magnetic part has a much higher tripping point and allows for inrush current. The thermo part trips when it gets too hot, and that'll be the current printed on the breaker.
Practically speaking, any intermittent device that _can_ run continuously or can fail to a continuous needs to be considered as such for safety purposes.
For example, a fridge should only run the compressor intermittently, but it has two obvious cases where the compressor could run indefinitely:
* An influx of heat, like filling an empty fridge with room temperature cans.
* A door being left open.
In the case of the kettle, it will likely be evaluated against it's "nominal" draw after the initial startup. If the auto-off sensor were to fail, it could run continuously at the tempurature.
I probably can’t speak to your jurisdiction, but no electrical inspector I’ve ever met would consider those loads continuous - in its precise, non-colloquial meaning - for the purpose of rating the circuit.
An appliance manufacturer may be under different UL regulations for failure modes of a device on a specific rated circuit. I don’t know anything about that.
Even in the context of your refrigerator example (which I don't necessarily agree with), a kettle should have two thermostats - a primary one that keeps the temperature setpoint, and a safety cutoff in case the primary stops working. In both fail and the kettle is somehow drawing its nominal power for hours at a time, the main safety hazard is going to be the kettle itself trying to dissipate >1Kw.
Yes, laymen and non-experts are going to use words to mean the wrong thing. NEC defines continuous load as 3 or more hours of uninterrupted demand. If you want to use the amateur definition, go right ahead, but understand there's an accepted industry definition of that term, even though it looks just like normal words. :)
If this is the standard then everything is a continuous load. A soldering iron or a hair dryer or a blender might get left on forever, who knows. Maybe I want the microwave to run 24 hours a day. If everything is a continuous load, why would the NEC make a difference at all?
I would install an US 240V@20A receptacle and replace the plug on the kettle.
You can also wire a duplex 120V with the two phases (you might find this in some kitchens, and in my workshop). Then you can make a dangerous extension cord adapter combining the split phase 120V into one 240V female plug.
I'm struggling to understand how the British grid works, as an Italian transplated to UK. IIRC in Italy most residential circuit breakers have a limit of 3.3 kW, so it's pretty easy to trip it with a few appliances running, and we don't even use electric kettles that much.
Yet in Britain, with a 3 kW kettle, I've never managed to trip it, with a combination of laundry machine, electric oven, microwave, dishwasher. Is there no circuit breaker limit?
When when the UK was rebuilding the housing stock post WW2, ring mains (or circuits) were designed to both increase consumer safety and to combat the anticipated post-war copper shortage. This design allows for high integrity earthing and greater power per unit of floor area for a given cable size than a radial circuit. Most white goods (Dishwashers, washing machines, etc.) are locally fused and often ovens are on a separate ring with their own fuses in the distribution board. This is why you rarely trip the circuit. It can be done though.
Post WW2 for newly built small flats, ring mains were designed to save on copper (as it was in shortage). The intention was to allow for 3-bar electric fires to be operated as 13A loads, and be moveable between rooms.
Rings are more complex to test, and have nasty failure modes. I'd argue that they should only be used in said small flats, and that 20A bus/radial runs should be used in larger builds. i.e. any modern house, rather than a flat. Said run the supplying all of the sockets in any given room, it does though require a larger "consumer unit".
The rings have a 30A (or now 32A) at the "consumer unit" (distribution fuse box) with two cables running in a loop around all sockets in the circuit. The cables have traditionally been 2.5mm, and open clipped, so rated at around 27A (based upon preventing overheating).
Hence when operating properly, the wiring in the circuit can carry 54A, the circuit is fused at 30A (or 32A) to protect the cable, and an individual load is limited to 13A (being the highest cartridge fuse commonly available).
There may be several circuits, and they all have independent breakers. Certainly, an electric cooker/oven will be on its own circuit as it has higher requirements.
Then, standard ring circuit is 32A, and individual sockets are limited to 13A (via fuse in plug). So you will need to have 2 kettles on on the same circuit and then add a third device pulling not an insignificant amount of power (32 - 2x13 = 6A) before the breaker trips. This will be safe if the ring circuit is not faulty as they are usually wired with two 2.5mm2 cables (two because it's a ring) that have a standard rating of 24A each...
UK electrics are mad - with the ring main and what not requiring fuses in the enormous plugs. All vestiges of post-WWII design. By code a modern American kitchen must have:
- dedicated 50A 240V for an electric stove or oven (unless gas service is present)
- dedicated 20A 120V each for the fridge, microwave, dishwasher, disposal (the latter being uncommon outside the US and Canada). The last two often share a circuit.
- two 20A countertop circuits with GFCI protection (what the Brits call 'RCD' - the difference being ours trip at 5mA vs 30mA and won't knock out half the house.)
You assert that it's mad but then describe a mad situation in the US.
A typical British kitchen will have a ton of sockets (although never enough), to plug in a fridge (or two, or three), a microwave (or several - they rarely goes about 1kW anyway), a dishwasher, a washing machine, a tumble dryer (UK kitchens tend to have washers and dryers, rather than bathrooms. Larger houses have separate utility rooms)
The only thing on a dedicated circuit would be a hard-wired oven.
Thinking that having dedicated independent circuits is madness sounds like Stockholm syndrome. The point being a single faulty appliance won't knock out the lights and sockets to half the house simultaneously (a common occurrence during a fault in the UK, especially the RCD). It's also quite convenient to switch off a single appliance for service. Yes British sockets are all switched but not necessarily in a convenient location.
A software analogy would be running all your services on separate VMs, as opposed to running them all on a single server which could go down at once.
Brits don't even put outlets in the bathroom, minus a current-limited transformer-isolated one for an electric razor.
Ah, the regs have changed and we can now have a full socket in the bathroom as long as it's far enough from the bath (.6 + 2.5 = 3.1m from edge of bath), which rules out most bathrooms...
My apartment in San Francisco which I pay an absurd amount of money for has just two or three 20A circuits in total going by the breaker. I regularly trip the power.
How old. What you describe sounds like it was built before 1970 and never updated to modern standards. Since the wire is often in okay shape few consider it worth the cost to replace it even though it really can't supply enough power for modern uses. (often you have to replace it all as if you touch it the insulation will break and then it isn't okay)
> in Italy most residential circuit breakers have a limit of 3.3 kW
Wait, really? That’s seriously underpowered, though I guess if you never need electric stoves or heating it could be somewhat usable. An ex-Soviet big-city apartment building will usually support 40A (~9kW) per apartment, and in France I had the impression that the values were similar—except for student dorms, which are supplied and wired like apartment buildings despite the density of occupants being 3x that or more, because apparently the builders could not into engineering and the uni authorities find it easier to blame the occupants (yes, I’m still a bit salty about that).
I haven't lived in Italy for 10+ years, so I don't know if anything has changed since, but that was the limit for all houses I've lived in, and from a quick Google search, it depends on your contract — the lowest is a 2 kW limit, 3.3 kW is the most common, and you can ask for an increase for an additional monthly fee. Heating and stoves are usually gas-powered, we don't do electric except for water boilers.
I have always wondered if those limits and the high electricity costs are because Italy abolished nuclear energy post-Chernobyl, doesn't have a massive oil and gas operation, so most of it is imported at a premium.
We should thank whoever came up with the idea of abolishing nuclear power in Italy. What a big mistake!
> if you never need electric stoves or heating it could be somewhat usable
Heating and stoves in Italy are usually gas-powered. Ovens and kettles are electric but normally do not exceed 3.3 kW, however, we need to be careful not to use too many high-consumption appliances together (e.g., oven and washing machine).
The introduction of increasingly restrictive energy classes for electric appliances in recent years has mitigated the problem to some extent anyway.
Italy has almost the same per-capita electricity consumption as the UK. I suspect any residential limitations are made up by industrial and transport usages.
You guys really need to get on the solar panels, though.
That ~9kW is probably split over 3 phases. Here you have 3x20A main breakers and then each circuit has a 10A or 16A breaker. So about 3.7kW limit for larger appliances (16A * 230V) on a single circuit, but should not exceed 20A on one phase. Stoves can be connected to 2 phases, 400V and get 7.2kW.
In the Soviet system, usually not. There are often several downstream circuits with their own 20A or so breakers and wiring (e.g.: kitchen stove, normal kitchen sockets, bathroom sockets and lighting, other rooms’ sockets, everything non-wet lighting), but each apartment is normally supplied from a single phase. On the other hand, different apartments on the same floor (or different single-family homes on the same street, etc.) might indeed be supplied from different phases. Normal (Schuko) wall sockets are most frequently 16A (so yes, 3kW kettles max), stove sockets (and circuits) might be up to 32A, still single-phase.
(That’s not to say the system is ideal, of course. E.g. GFCIs have become common only in the past fifteen years or so, and in a country-home setting I’ve actually encountered disposable screw-socket [IEC 60269] fuses.)
In a perfect world a ring circuit is a clever invention - it offers a circuit that can safely deliver about 7.3kW with hardly any more copper than normally could deliver about 4.6kW.
However in practice they have a hidden failure mode - if you break the ring they will carry on working apparently without problem except it’s quite possible that you now have overheating cables in a wall somewhere. In the real world houses are full of changes (both DIY and professional) that inadvertently break the ring and it’s not at all uncommon to see in a house with even modest refurb works having been done.
Going from memory but this is an artifact of WW2. There was a copper shortage so they decided to save on wiring costs by running only a few high current circuits through the whole house. The appliance plugs are instead fused as any fault in the appliance would happen after the plug. This is why UK plugs are all fused - they are the final branch circuit over current protection device. I actually like the idea.
> I'm struggling to understand how the British grid works
Like most things, understanding the history helps. The ring circuit was designed because it uses less copper than other methods - and copper was scarce after WWII. Almost all other design decisions either come directly from the idea of saving copper, or the idea that there are not enough Legos to step on so the electric plug must substitute.
That sounds almost as bad as what we have to deal with in the US!
I live in an early 20th century apartment in San Francisco and I quickly learned not to run my 1.8kW kettle at the same time as my 1.2kW microwave as it would consistently trip the power.
More annoying is when the fridge compressor motor starts up while running either as that also trips the power.
The difference really is night and day between a US and UK kettle.
The worst part of the British system though (although I don’t think this has anything to do with voltage, IDK) is there is nowhere to plug-in your razor, hair clippers, hair dryer, toothbrush, curling iron, etc. etc.
That's building regulations, sadly. Sockets need to be multiple meters from splash zones, but there's an exception for shaver sockets, which have their own transformer, limited amps, and have a plug that looks very similar to the non-grounded EU plugs.
Yeah, both bathrooms in my (UK) home have such sockets, I don't actually use them, the electric toothbrush gets charged by this desk instead, but they exist.
Regulations change over time, this home's bathrooms are all interior, with fans to evacuate moisture, and the toilets accordingly have internal overflow†, both these features were not legal when my parents home was built.
† Historically for a residential toilet in the UK if the water rises above the intended maximum level in the tank, it just runs into a pipe to the outside of the building, in principle you can now see what's wrong and it's not dangerous... but, if you don't fix it promptly this results in a stain on the building exterior, as well as potentially wider water damage, plus it can freeze in mid-winter which isn't good. But wait, a toilet has a very obvious place to dump unwanted water, it's connected to the sewer and if that is broken you've got much more serious problems. So a modern toilet tank just re-uses the flush mechanism to dump excess water the same place as everything else. This elegant solution, already needed in some commercial applications, was I believe made legal in newer residential building regulations maybe in the 1980s.
Thank you, now I have even more highly specific but useless information about British homes. It will sit next to my knowledge about why you guys (used to) have two faucets.
Yes - though we call them RCDs and they're typically located in the consumer unit. Up until recently they'd be shared across several circuits (a "split" or "dual" RCD consumer unit). Nowadays regs are pushing for each cicruit in the consumer unit to be protected individually by their own RCBO (almost the same thing as an RCD/GFCI)
No, we can still do that -- I have a dual-voltage shaver point next to my bathroom sink with my electric toothbrush plugged in.
There's a famous, common 20VA fixture by Legrand with a distinctive symbol. I asked an electrician about this last year. Most electricians will still fit them.
It won't supply a hairdryer or a pair of curling tongs, probably. Not that you really want such things in a bathroom or without an earth pin.
Yeah, it's fine for me as all my stuff is rechargeable and cordless anyway. But my wife needs her hairdryer. In the US any plugs that could get wet are GFCI [1] so you just wait for it to dry out and then push the reset button.
I've rarely had it happen in the bathroom, even with outlets right next to a sink. But I had an outlet at ground level outdoors that would trip during heavy storms sometimes. We fixed it by putting a physical cover over it.
As an American, I find the boiling speed of 1L in an electric kettle to be remarkably fast compared to drip coffee or boiling on the stove. Granted, that says more about my expectations than the actual speed.
Generally I use an insulated 4L kettle that stays warm all day, so it heats up very quickly when needed and somewhat negates the issue.
I find with electric kettle that I use the right amount of water since there are markings for volume. It also heats up to the right temp for coffee instead of to boiling. Both mean that electric kettle is faster than on stove. I like that it will maintain right temp for the second pour for coffee.
An induction stove is still really inefficient at heating water, compared to an electric kettle with the resistive element in the water and 3kW of power.
There is a small difference but not much. I compared my 230V Kettle with my 400V induction stove and it’s within 5% or so. Obviously it depends a bit on what pot you use. I’m guessing most losses come from the lack of insulation on the metal pot.
For the induction cooktop, there's circuitry to drive the induction system, which then creates magnetic fields, which then interacts with the metal pot, which gets hot and heats the water on one side while radiating heat into the air on the other. There's a lot of stages for losses here.
On an electric kettle, there's just a heating element, often directly bathed in the hot water.
There's absolutely less losses with the electric kettle, so for a 3kW kettle and a 3kW induction cooktop the kettle is slightly more efficient. Slightly.
Hmm, I measured it once (temp increase over time, computed back into watts, compared to a watt meter on the induction cooker), and I found that of the 3,5kW I put in, 80% actually convert to temperature increase in the water. That is not too bad, is it? Are electric kettles more efficient?
Are people actually using induction stoves for tea, though?
For me, a big selling point of the kettle is that you don't have to clean it and stow it after every use, so I would still use the kettle even if it was slower (maybe no longer for pasta or when cooking in general though)...
edit: I guess you could just get a teapot that is induction-compatible, didn't think of that.
Ours is a Smeg model. The two large rings are 2.3kW, with a outer booster ring to 3kW. The problem is if I'm just boiling water for my tea with a saucepan, only the inner ring is triggered. I can put a large pan on there and get 3kW to match the 3kW kettle, but then I've got to warm a large metal pan too, whereas the kettle has very little thermal mass and is lightweight and easy to fill too.
A properly sized tea kettle would solve that but since you already have the electric kettle there’s no sense in buying a new stovetop vessel until the electric kettle burns itself up.
US induction cooktops/stoves are almost always 240V, unless you get a little countertop burner.
> I'm kind of surprised by this.
As am I. The first time I put a small pot of water on my induction cooktop and turned it on maximum power, I laughed out loud. If I'm only doing enough for a cup of coffee or tea, it starts boiling so fast you don't want to step away.
My in-laws have fried three different induction hobs boiling a kettle on them. Good quality brands too, they just can't seem to cope with frequently being set to max.
No, it really does not. A typical induction stove has ~2kW of power on each element, and is ~20% less efficient at heating water than the resistive kettle.
This makes it about half as fast at boiling water.
Note that the 3.7kW element can only provide all that to a single vessel if it covers the entire area of the element.
The resistive element submerged in the water dumps very nearly 100% of energy into the water. The stove heating the kettle has many more sources of loss, but mostly that it first heats a piece of metal, which is not fully submerged in water.
In theory, in practice the induction heating on a regular pan is faster than my kettle by almost three times. YMMV on type of kettle and induction hob used. But it generally means that if you live in the US and you have an induction hob, there is absolutely no reason to buy a kettle.
My experience with US induction stoves is limited but I believe it can also deliver 3.5kW on boost. My induction stove boosts to 3.8kW for heating which beats my kettle significantly. I also measures the efficiency and it’s quite comparable.
A British kettle on 230 volts boils enough water for a cup of tea in about 45 seconds. (3 kilowatt heater, 300 ml of water, theoretically takes 33 seconds, but slightly longer because it has to heat the body of the kettle too)
Install an A/C socket in your kitchen. Then buy a British 240 volt 3 kilowatt kettle from eBay and wire on a US A/C plug (NEMA 6-15) - hooking the brown and blue wires from the kettle to the two line pins, and the green/yellow wire to ground.
This would be both code legal, safe and functional.
It would also be possible to use a clothes dryer socket (NEMA 14-30), but you should install a smaller than usual breaker for the circuit (15 amps), since the british kettle normally has a 13 amp fuse in it's plug, but a NEMA plug does not contain that.
Pretty much. My office building was formerly a woodworking shop and has wiring for 220V. Long ago I bought a laser printer on eBay. The seller omitted to mention it was a 220/240V model (probably why it was cheap). Laser printers unlike most appliances are not dual voltage because the fuser is run directly off the ac supply line. So I wired in a 6-20 outlet and changed the plug. Worked fine for many years. I also have a table saw running from a 6-20 outlet. There is a 6-15 NEMA type that presumably would provide a UK compatible supply. I think the problem might be how to provide in-wall cabling that's to code for 220V. In my case I already had conduit with THHN wire.
Not necessarily to code, consult your electrical engineer and lawyer before doing your own wiring, etc.
> I think the problem might be how to provide in-wall cabling that's to code for 220V
That's no problem, standard romex nm-b is rated up to 600V. The only real difficulty in doing that in most US homes is that it's all or nothing. You'd have to upgrade all receptacles on the circuit to 240V. Depending on when your home was built, the kitchen might well have several circuits for the wall receptacles (even just one circuit per receptacle, not terribly uncommon in my area), which makes converting one of the circuits to 240V pretty trivial.
Given how many appliances these days use switching power supplies capable of a wide range of voltage, I wouldn't be totally surprised if it was possible to wire an entire house with nothing but 6-15 or 6-20 receptacles and not have too much difficulty sourcing compatible appliances.
I believe that US code requires a dedicated circuit for all 240v outlets. Only 120V outlets can be chained. The only people who use 240v outlets are planing on using all the power it can provide, if they want a second outlet they want a second circuit as well.
Check with your local codes of course. Even if the local codes allow it, your building inspector may not.
Most kitchen appliances require the right voltage. They normally have a heater or motor driven direct from the AC voltage.
Most devices you'd use outside the kitchen usually will work on any voltage - with notable exceptions being vacuum cleaners, washing machines and fan heaters.
For sure you'd want to be careful. My Kitchenaid stand mixer would certainly be unhappy if it were plugged into a 240V outlet, but Kitchenaid makes a 240V version that I could replace it with. A lot of work, but technically doable.
Probably about as likely as wiring up DC receptacles throughout the house. Zero.
12-2 NM/Romex is fine for 240V (120V+120V), and is commonly used for things like large ACs, heaters, etc. Mark the white wire with red electrical tape at both ends (or really any color besides white/grey/green, but avoid black because while technically correct it just blends in as regular electrical tape).
Any kettle with a flat bottom (no exposed heating element) can be used with far less water than the 'min' line - and some models don't have a min line at all.
All new kettles have boil-dry protection as well, so they won't be damaged with no water at all.
We drink an unbelievable amount of tea. Firing up the hob each time would be silly, when you can fill a kettle to the minimum and have boiling water in an incredibly short time. Not much more than half a minute with a good modern kettle.
It does in theory. There are a few taps in the UK that are marketed as being able to produce essentially boiling water (which is what our typical tea bags require). Though we tend not to put quite so much money into our kitchens.
And we would wear those things out, I swear! :-)
I think Americans think British people drink tea out of poshness, when it is the opposite. Most of us also like a posh tea now and then, some of us drink expensive leaf teas... but the majority of what we drink is optimised for fast brewing off boiling water: tea that goes black in the mug in thirty seconds in boiling water.
There is a concept here of "builders tea" -- the kind of thing a builder drinks -- which is sort of the functional equivalent of cheap electric coffee-pot coffee. That is, it's the kind you know isn't the best, but you will still drink it, and that cuts across all class lines. [0]
There is a parallel thing: the "tea urn", which is like an enormous samovar with a lever -- that you still will see in industrial canteens and at church coffee mornings and at gatherings that aren't at cafés or restaurants. Those things actually need a different kind of tea, which brews more slowly and at slightly lower temperatures. The end result is a bit like builders tea. But we wouldn't bother with them at home.
[0] We do absolutely drink coffee at home, but aside from appalling instant coffee we tend to skip over the coffee-pot coffee in the UK, to slightly more expensive ways of making coffee or to dreadful Nespresso machines. You'll see more of those or Bialetti mokas here; old style electric coffee pot percolators are now rather unusual. But Alan Adler's Aeropress particularly caught on here among coffee nerds, because that is really compatible with electric kettle life.
> USA uses 230-240 VAC, too. The only difference is that we ground it in the center, creating "split" phases, reducing the peak voltage relative to ground and making it easier to interface low-power loads. But high-power loads (stoves, water heaters, clothes dryers, etc.) operate across the full voltage, reducing the current required.
They generally don't blow at the rated current. I've reliably used a 13A fuse on something that draws 16A for a while when starting up and never had a problem. Obviously RCDs etc are more accurate, but wired / cartridge fuses are always under-rated, in my experience.
Most fuses are slow blow - they will allow somewhat over the rates power draw for a while before blowing. Many things (motors) take a lot more than rated current for a few seconds and this is perfectly safe so the fuse shouldn't blow. The purpose of the fuse is to prevent a house fire, if your wires are good for 13 amps that means at 100% duty cycle, you can draw 16 amps for "a while" before the wires get hot enough to burn the house down, so long as you drop under 13 amps for "a while" so the wires cool down and never get hot enough to start a fire the fuse is working.
Note that the above is about safety. If you are going to draw 16 amps you should stick to a circuit rates for that, as it will have less resistance and thus waste less energy.
It's possible to ask an electrician to install a 240V outlet in the US and then get a UK-spec kettle. You just need to make sure the kettle doesn't care about the frequency difference (probably not), and the hot-hot vs hot-neutral difference (also probably not).
Possible, but the outlet will have a different plug. Most window air conditioners use that type of outlet, and some garages will have it for hobby equipment. I don't think you can legally install a UK (or EU) outlet in the US even though everything that plugs into it would be just fine on our 240V power (a few clocks won't work right, but they won't be harmed or harm anything)
Presumably, you would chop off the plug on the UK/EU kettle, and replace it with your own NEMA 6-20 plug. No need to install a UK/EU plug in your house. Also works good in case you need to use some sort of weird industrial equipment that needs 240V.
Does anyone make a.travel adapter that plugs into a us 240volt socket? Such a thing is easy to imagine, but most houses don't even have an outlet you could plug it into, so the demand would be small.
I would not use a travel adapter for a kettle. They pull major current, and the quality of the travel adapters is generally not intended for that much current draw...
Somehow I've never considered my home kettle too slow in the US, even though I have tea probably 2-3 times a day. And there's an instant hot water machine at our office, so it's not like I've gotten used to slowness.
On the hot beverage topic, I'm jealous that the espresso gear in Europe is a little cheaper/faster. The motors that drive coffee grinders and the heaters that heat up water in the boilers work a lot easier/faster.
I used to sympathize with this take until I bought a Zojirushi water boiler, which provides instantaneous hot water. Now even a faster kettle is a downgrade in experience.
Most Americans drink substantially more coffee than tea, which is why we have a purpose built appliances for making coffee, and have had those for decades.
The reason Americans don't have a super fast boiling kettle is that very few Americans WANT a very fast boiling kettle for large portions of water. If an American wants a cup of tea, two minutes or less in the microwave is sufficient. I don't care if you think that's bad, because I want a cup of tea, not some elitist purity contest.
Errr... we have those too. Though we get our coffee trends from Australia and New Zealand.
And tea in the UK has absolutely nothing whatsoever to do with "elitism", which is something you projected onto what I said for your own reasons, I guess. The very opposite: tea serves the same function as coffee does in the USA, cutting across all class and status.
In fact the kind of tea you drink in the USA tends towards being what people here would call "posh" tea, because you drink the more unusual, expensive stuff as infrequent drinkers. Most of what we drink is robust and cheap.
Americans find our tea to be the same way we find your coffee: a distinct culture and taste that is acquired, not instantly loved.
(We'll leave it to the Aussies and New Zealanders to talk to you about your coffee; they came over and fixed ours.)
But I am reminded that it is foolish to try to convey a point in a humorous way on Hacker News.
And to follow up on this thread because a similarity occurred to me in another reply, we do use samovar-type things (electric tea urns) in other contexts (ad hoc and mobile catering), but that is about brewing the tea itself within the vessel and it requires both a different kind of tea and a noticeably different kind of scale (simultaneous volume). You do sometimes see those in company canteens though.
Typical British teabag tea -- the stuff we consume in quantity -- is brewed with water just off the boil, and consumed often pretty quickly afterwards because cold milk gets added.
(Or it goes into a teapot for brewing, and again needs to be just off the boil for that)
Given that we can boil a kettle for a mug's worth of tea in not much more than half a minute, there's no reason to use them, I think.
People like to joke about this but the reason it's called a "boiling vessel" and not a "Tea maker" is because it's incredibly useful other than just making tea, to the point that the US has also added them to many modern vehicles.
On demand hot water, from the safety of your combat vehicle, is a genuine war innovation on the same level as canned food. Especially now that combat vehicles are aiming towards having more robust electrical systems makes it trivial to implement. Hot water means hot food, means warmth on a cold day, means sterilizing sketchy water sources without chemical tablets, means you don't have to light a visible fire to make your coffee, means you keep morale way higher. Your troops are now cleaner, better fed, happier, more motivated.
Light bulbs in the early 1900s were first designed for lower voltages, and the grid slowly raised things over time, but at some point they couldn't go any higher because it would start blowing things, so they were 'stuck' in the 110-120V range.
The 50Hz and 60Hz is quite noticeable. I'm used to hearing mains hum at 50 Hz, so hearing it at 60 Hz sounds a little different. (You can sometimes hear it in audio recordings etc).
There was a video recently where YouTuber diodegonewild was fixing old power supply, he turned it on, listened to it and said "the transformer has DC offset on it, because it's humming at 50Hz, the magnetostriction doesn't care about polarity, healthy transformer hums at 100Hz, I think one of the diodes in bridge rectifier is bad" and he was right.
I'm not sure there is a good answer, beyond "the US stuck with Edison's 110V, Europe went with 230V because it's cheaper". Both 110V and 230V are reasonable choices. And of course technically the US primarily uses 230V split between two phases. But Europe mostly uses 3-phase 400V, with each phase delivering 230V (because phases are 120° offset to each other), so then we are just talking about 230V vs 400V, and two vs three phases.
Are they, though? With modern appliances, power requirements are going up and 110V is struggling to keep up. One example would be an induction hob.
I know that technically US homes can access 230V but they aren't wired for that, probably 99% are wired just for 110V except for maybe a few special lines.
Every US home I've lived in had 240V access in the kitchen for appliances like electric ranges. They absolutely are wired for that. Practically nobody's house only has 120V.
It sounds like you've always lived in relatively new/high end houses then.
Older houses might have a dedicated 240 plug for the dryer and the stove if they're not natural gass, but for everything else there are plenty of homes full of ungrounded 10 amp 120v circuits.
My current house was built in '82. Is that a new house? That's 41 years old at this point. Its a pretty average single family suburban build for the time, not anything especially fancy even for its day. Loads of houses we looked at in the area were built in the 70s and 60s and often had electric 240V appliances in the kitchen. That's about 60 years old, is that a new? A single car garage 1500sqft 3bdr house in a suburb sound like a high end house?
And yeah, my house is full of 120V circuits, but once again the house has 240V at the panel and could run 240V anywhere in the house if needed. As you pointed out, they probably do have a 240V plug for the dryer, ergo they've got 240V service at the property, so they could wire the kitchen if there's no wiring already. Once again, practically nobody has only 120V service at their home.
Yeah the only situation I can think of only 120v being available in a house is if it is a separate unit running off a 120v sub panel from the main building. The other option would be some off grid setups for like a tiny home might only run 120v. That is mostly because anything that would require 240v would be too power hungry to run off of the solar system.
That would be by choice, though. My mom's 110 year old house still has some circuits with cloth wiring. But it has a number of new (40-50 year old) circuits that are normal, grounded 5-15 120V. And the kitchen, basement, and garage have 240V receptacles. This is pretty much the same setup as any modern house.
Laundry, stove, and ovens use 240V outlets (assuming no gas). It’s not very common but I know a few people with wood working tools who have installed 240v outlets. Wood framed houses make it easy to change wiring.
To change my gas stove/oven back to 240v induction would be a 15 foot run of romex, a new outlet, and probably an updated circuit breaker. Possible for a DIYer to do.
Compared to the age of CRTs, modern TVs are much more power efficient.
And compared to the age of the Pentium 4 with its 100W+ TDP, laptops now outsell desktop computers by a long way.
(I would agree that things like high-end gaming GPUs are using more power than ever before - but they're also a much smaller % of sales than ever before)
> Compared to the age of CRTs, modern TVs are much more power efficient.
According to the internet a CRT TV used to use about 100W, while a big LCD TV can use more.
Regarding desktops, don't forget that these days we have many more electronic device in a home. Smart speakers, home media devices, consoles, etc, etc. Electronics probably use, in aggregate 5-10x what the old family PC used to use, I'd imagine.
The CRT TVs back in the 70s and 80s were pigs. Not 150W, more like 300W and sometimes more. It would take some work to make a modern LCD with similar consumption. Even when plasma was all the rage, it wasn't that bad.
Fundamentally the US just wires things differently. If a house has an electric or induction hob(Cooktop) it will be permanently wired for 240v. All your high power devices such as HVAC, ovens, cooktops, and EV chargers have dedicated lines at 240v for them. Every house in the US other than some super niche scenarios has 240V. Yes largely most everything is wired for 120V and only a few special lines at 240v but that is because those are the only things that really require more power.
Largely they have the same power output. While the total power available is actually higher for the US version at 12kW versus 11.1 kW for the UK version. That is because the US version needs to be on a 50 amp 240v circuit versus the max 16 amp circuit for the UK version.
The max output to a single pan/pot typically is going to max out around 3.3-3.7 kW. I don't know the exact reasoning behind that but I assume it might cause issues with cookware if you go much higher than that.
Power = V*A. You can get any given power output out of any voltage by following the formula. The number of wires is not a factor at all. Number of wires and voltage is a factor in cost of install of course, but nothing else.
Interestingly enough, European oven/hob combos mostly run on 400V 3-phase power. Same for many tankless water heaters. That's certainly one advantage of 230V per phase. It's probably also one factor in the decision to power things by gas vs electric.
But are they more powerful? AFAIK it's pretty common for a European range to be in the 7000-10000 watt range. That's also normal in the US on single phase 240V. And I can go buy a 36000 watt tankless water heater from Home Depot. I think it's a wash, either system can deliver however much power you need.
The reason for gas in the US is because people like it. It's been seen as upscale for decades to have a gas cooktop. It also helps that gas water heaters don't require electricity and work in an outage. Our residential natural gas distribution network is extensive and reliable, and it's pretty straightforward to use the same appliances on propane for people out in the sticks.
Depending on the market it can also be cheaper per BTU to heat with gas than with electricity, at least resistive heating. Heat pumps are starting to challenge that math, but with higher upfront costs and more complexity as tradeoffs.
US Power is typically 240v split-phase, a single phase, not two phases. The transformer is 7200v to 240v. The Neutral line to your house is center tapped on the transformer giving you 120v from Hot to Neutral and 240v from Hot to Hot. I have L14-30 and L5-30 outlets throughout my house and property for example which lets me run higher voltage/amperage workloads more easily. My workshop has an isolation transformer which is 240v primary and 120v secondary. This allows me to run 80A of 120v "stuff" in my workshop but it's a 40A 240v load from the perspective of the main panel in the house.
Interesting, I haven’t heard of anyone doing this before. What is the advantage?
Assuming 120v loads are split reasonably equally between each leg of the 240v phase, the load will mostly be on the 240v circuit because both legs are connected in series. The neutral back to the transformer is only used to carry the difference between the 120v load on each leg of the phase, and also to keep the system grounded.
I guess if you had a panel close to load capacity, as well as a single very high amp 120v device, the transformer could enable some more capacity by ensuring the load was distributed equally between the phases. However at that point a service upgrade would probably be necessary anyway based on the load calculation rules in the code. Also high amp 120v devices are quite rare as far as I know, so I was wondering why you went with this unusual setup.
So, not only is the UK 230v, it's also wired in a ring (i.e., your circuit isn't a branch from your junction box, it's a full loop). So, for a given power capacity, you can use much less copper.
UK fixed wiring circuits, unlike those found in almost all other countries, make widespread use of ring circuit designs, as well as radial circuit designs often seen in other countries. (This was one of the recommendations of the Electrical Installations Committee, convened in 1942 as part of the Post War Building Studies programme, which in 1944 determined that the ring final circuit offered a more efficient and lower cost method to support a greater number of sockets.[6]) It continues to be the usual wiring method for domestic and light commercial socket and device wiring in the UK. Lighting circuits, which typically have lower power requirements, are usually radially wired, confusingly sometimes called "loop" wiring.
So, the why is: More power, less copper, and that's really useful when you're resource constrained because someone has declared war on you and is blockading your coast, or you're recovering from that.
Safety was one significant concern. 230-240V is more likely to stop a person's heart. 220 is available in most US homes for specific cases where it is more practical.
Speaking from experience, I don't think it is uncommon for a person to have been electrically shocked at some point in their lives --- often when they were a child.
Maybe common in the US. Europe takes plug and outlet design more serious (as a consequence of 230V), and while the UK plug and continental Europe's Schuko plug are very different both make it basically impossible to accidentally shock yourself.
Not impossible with the Schuko, it's still possible for something to get caught in it and touch the pins when it's partially inserted, that's happened to me. It's better when only the tip of the pins are exposed, as on the UK plug and the Europlug.
On UK plugs at least, there are shutters and you need to insert something into the earth pin slot before they will allow you to access the live/neutral pins. On better sockets, the shutters then need simultaneous pressure on both live/neutral to completely release. The actual contacts in the socket are recessed too.
UK plugs and sockets are really, really, really safe. Except to stand on.
There is a hole cover plate that has to be pushed by rounded plug pins to pivot and unlock the socket holes.
You can try pushing with something like a screwdriver (to test for live) and it's hard to pivot the plate (feels like it needs both pins to pivot), and a non round tool snags on the plastic cover plate.
In the US code requires shutters so you can't stick anything into the socket other than the correct plug (IIRC as of 2008?). Other responses are implying the UK (and I assume EU) now require that too.
On the other end, in India I saw a power strip that would accept EU, UK, or US plugs. I took one look and refused to get close, but someone else plugged my laptop in and it worked. (everything got 240 volts, which my laptop power supply was fine with)
No EU-regulation for that I think, it depends on the country. British Standard 1363 has had mandatory safety shutters since it was introduced in 1947 (not sure if you could still use the older British Standard 546). Here in Sweden there is a building regulation from 1988 stating outlets should be placed or designed to make it hard for children to insert things into them. I was surprised to learn that wasn't common in the US, at least until recently.
Wire insulation deteriorates over time. Rodents like to chew through it. Water can find it's way in through plumbing or roof leaks. Higher voltage is more likely to start a fire in these instances.
I'm in Europe and I've been shocked a few times by 220V and I know plenty of other who has too. It's usually not from regular wall sockets, but wires with broken insulation or working on things where parts of a circuit is uninsulated.
And to me this seems most obvious answers. With possibility that you had other resistive loads at that voltage already sold. And people would be rather gross if they had to replace them.
The one explaining that Edison's DC system they were competing with, in the US, was using ~100v DC. And the public disinformation campaign characterizing AC as unsafe. Including attacking anything higher than approximately 100v as unsafe. That seemed like it answered the question to me.
The world is pretty standardised into these two now, but that can't always have been the case.
In the early 1980s, my dad found an old valve keyboard / organ thing at some jumble or car-boot sale that probably dated at least from the 1950s, and being curious I used to regularly take it to bits. One thing that was weird is that there was an input voltage selector on it, but it was a round thing with contacts arranged in a circle and a plug that would bridge one contact to the centre contact. The range of input voltages was 60VAC to 240VAC, and there were probably 10 or 12 different voltages in that range. Unfortunately, this was also how I destroyed the keyboard part (but not the separate valve amplifier that I continued to use for at least another decade) because the 60VAC was next to the 240VAC and I accidentally bridged it to 60VAC and fed it 240VAC. All the valves were powered at 4x what they should have been and there was a bang and nothing worked after that. In retrospect, I should probably have kept it as probably only a few valves took the brunt of power surge, but even then valves were hard to get hold of and these weren't all the same (my memory is fuzzy, but there were probably 30+ valves in the keyboard, I only pulled a few to look at them and they were obviously different), so we just decided it was something that didn't need to be repaired.
But anyway, long story aside - there must have been some demand for such a wide range of input voltages for the power supply, or they wouldn't have come up with a selector switch with so many possible options.
Every comment in this thread is mentioning a different angle of advantage/disadvantage between the two. I've given up on determining the winner, but that's ok, I'm just learning a lot about home power distribution.
That's because there is no winner. Nobody is doing something in the US that is impossible in Europe, or vice versa. There are upsides to both approaches, and different trade-offs, but everyone is getting enough power.
Though it is crass, I'll say it. A silver lining to the tremendous infrastructure damage caused by world wars in Europe is that ossification was interrupted.
I don't normally like YouTube talking videos, but this one is really good and to-the-point. Will say in response though, at least 120V makes this less of a safety issue.
Here is a really great video that goes over the history https://www.youtube.com/watch?v=7yRGvMgieEU
Sometimes we think about the technical reasons and forget of the human and the developmental process that can sometimes have an effect on how things are today. spoiler for the video - its because too many 110v light bulbs were already in place by the time 220v ones were made and it was too expensive/difficult to change. kind of reminds me of why the US never switched to metric.
What, you say? The UK uses metric, right? Yes, in much the same way as the US does.
Officially, the US gov't stance is metric. And in technical areas as well as much of the consumer space, metric is everywhere. What isn't really changing is layperson preference for units. People are comfortable with feet, yards, miles, Fahrenheit, etc. Just like the UK still using miles, and many normal people measuring weight in stones.
Inertia is a pretty important consideration, and not invalid. Imagine trying to convince the UK to drive on the correct side of the road at this point. ;-)
Better yet why does the UK use those ridiculous cumbersome over-designed plugs?
Or, even more curious, why are so many British authorities so bizarrely (to the point it's funny) protective over electricity, fining people and threatening to call police on people who try to charge their phones in train stations, for example?
It's a pain they are not the same as the rest of Europe, but what is cumbersome and over-designed about UK plugs?
Follow up question, why Swiss plug needed to be so close to the rest of Europe, but different anyway? (same distance between the 2 pins, but the pins are a bit thinner and the ground is in the opposite way).
The size is cumbersome, but folding plugs are available for devices like phone chargers - the dummy earth pin is retractable, so the overall size of the charger is essentially the same as a US or EU charger.
>I'd call having a fuse in the plug itself over-designed.
I wouldn't. A UK mains circuit typically has a 32A breaker. Pulling that much current through an appliance that's designed for a fraction of an amp or a cable that's designed for 3A is obviously a very hazardous fault condition. Some appliances have a built-in fuse, but many don't and that still doesn't offer the same level of protection as a suitably-sized fuse in the plug.
> The size is cumbersome, but folding plugs are available for devices like phone chargers - the dummy earth pin is retractable, so the overall size of the charger is essentially the same as a US or EU charger.
How much does a folding plug fold? Look how minimal this[0] is, I've never seen any UK plug anywhere close to that size.
> I wouldn't
Any reason the fuse couldn't go in the socket instead?
> Any reason the fuse couldn't go in the socket instead?
Because changing the fuse in a socket just because you're unplugging a lamp and plugging in a kettle would be very stupid. With the fuse in the plug, you have the correct fuse in every plug.
For one thing, AU 2-prong plugs have a much more physically secure connection than equivalent US plugs. The angled prongs mean there’s no rotational axis about which the plug can fall out. Of course it also means the prongs can’t really fold away for storage.
> I'd call having a fuse in the plug itself over-designed.
Personally, I'm quite happy that all my lower power devices with relatively thin power cables are protected by a 3A fuse. There's no risk of causing those cables to catch fire if there's a fault that draws 20A, which isn't enough to blow the 32A breaker on that ring.
How much difference it makes in practice though? Pretty sure that if I short the power at the device end of a 5A cable, the 32A breaker would blow before the cable caught fire. But I'm happy not to depend on that.
I've never had issues in the US/AU/EU, so I really question how useful it is compared to the amount of incidents it is actually offering protection against.
Seems to me it's somewhat like having an additional seatbelt for your head, which might protect against whiplash but isn't justified by the inconvenience.
The fuse in the plug was chosen to protect wiring on ring circuits. They could also have put the fuse in the wall socket. After all, they already put switches on them. Of course then you would have to go with the screw-in fuse design that was used in circuit breakers back then, instead of the fuse design in UK plugs.
Other countries don't use ring circuits to the extend the British do. We just rate every outlet to the specs of the wire in the wall, but the British have a 30A ring that serves multiple 13A outlets. As a consequence they need to protect the outlets (and device wires) from overcurrent somewhere in the circuit.
British plugs are big but they are flat (cable runs parallel to wall), which actually makes them less cumbersome than EU ones because you only need a small gap between wall and furniture/whatever.
A very significant fraction of Schuko plugs is also 90-degree angled, though. Angled is neat for furniture, but straight-out is better for unplugging and high-density power strips.
Granted I grew up with them, but I like them. They can be annoying to travel with, and accidentally stepping on them barefoot is very painful, but apart from that the size is handy. I've never had them slip out of the socket, for instance, like US or EU plugs.
> I've never had them slip out of the socket, for instance, like US or EU plugs.
Aside from old-style type-C plugs (two prongs) in old sockets, I've never seen an EU plug work itself loose in a socket, let alone slip out of it. Usually, there's the reverse problem: they're difficult to unplug, even when you want to.
That always seemed to me, to be a fabulous danger. Reach for your towel on the counter, tangled with the hair dryer cord and the hair-dryer is pulled into the bathtub. Yow!
In the US, the cord would likely pull out of the wall, safely.
What hairdryer? British building regs restrict you to an isolated "shaver" socket in the bathroom which takes different plugs. You can't drop a hairdryer in the bath unless you play silly games with extension cables.
The British paranoia about bathroom electrical devices has always amused me. Stick a GFCI on every outlet in the bathroom, then it doesn't matter if you're swimming with a toaster or an electric shaver. Heck, it was uncommon to even find a light switch inside the restroom.
Oh, another fun fact... Historically, the UK was 240V and Europe was 220V. This was later standardised across Europe as nominal 230V +- 10%, and AFAIK both UK and mainland Europe carried on as they were without actually changing anything!
220 VAC allows higher gauge (thinner) wires for the same wattage consumption and more watts per circuit for the same amperage (more powerful appliances and/or more concurrent appliances without tripping a breaker). And the UK in particular has far safer plugs than the US, with a fuse in every plug, partially insulated plug leads, and blocking shutters on the sockets.
So basically we could use less copper, have safer homes, and simplify power supply design since we (and a handful of other holdouts) are basically the only countries using 100-120 VAC rather than 210-230 VAC, which would lower costs and reduce waste.
I’ve lived in UK, Europe, and the US and I don’t really see a problem with either system. The 120V system is perfectly sufficient for most cases, even refrigerators and other large appliances. I suppose the one advantage a 220V system has is that you can put a stove or dryer anywhere, and you can run certain appliances, such as steamers and irons with way more power. On the other hand I find the UK’s plugs to be comically large compared to the US’s petite counterparts. Some European houses even have a few 3-phase 380V outlets for heavy duty equipment, which would be exceedingly rare in the US.
But it is allowed in most of the rest of Europe. I believe they do require those to have GFCI (as does the US since 1975). Does the UK disallow them even with GFCI?
Most bathrooms in UK hotels will have two pin 115v & 230v outlets for shavers. You can get them installed in homes too I believe, but most residential properties don't have them.
They really are just for shavers though. You can't run anything high power without blowing the fuse. I believe Americans often use hairdryers in bathrooms. We definitely can't do that.
That said, we do have electric showers in UK bathrooms but legally those need to have a kill switch installed.
It's not all that weird though. Until the 1970's we had (in NL) 127 in some and 220v in other places which could either be 127v to ground, 220v to ground or 220v line-to-line. By around mid 2000's everything was switched to 230/400v for standardization in Europe, so it's not that long ago we still had some lower voltages.
I found it somewhat funny that the question included:
>Explain me with calculation.
As with many things related to technology, decisions are very often made for seemingly arbitrary (or political, or economic, or competitive-advantage) reasons, not because of some calculation that was done that proved a decision optimal.
My understanding is that this choice is a balancing act between having good efficiency for long distances transmissions (230v) and having a lower peak load in the grid (110v) for desely populated areas. But I'm no expert in this matter.
Where I live (Brazil) is commom to have both. In the big cities you will find 110v and outside that you are more likely to find 220v. And yes, it is a pain if you move from a 220v city to a 110v one. But besides that most people don't care about having 2 standards.
For anyone interested there is a semi-relevant TechnologyConnections video[0] where he discusses the popularity of kettles as way to heat water in the US.
The lines in your neighborhood that feed your house are 7200v, that goes into a transformer in the yard or on the pole which provides 240v to your house. Larger transmission lines are 38000 volts. There are other voltages in place as well.
My guess: in the old days when electricity was new, power conversion was done with Rotary converters which were basically a fused motor-generator. To change voltage you had different winding and number of poles. So if you were at 60 Hz, you have the magic of being divisible by a lot of numbers and you could easily go up down by common integer values.
Then when Europe was standardizing, they wanted to be all metric, and 50 was close enough to 60 and still could become 100 by doubling.
I don't know, those are just pure guesses.
I think when you come from the engineering/tinkering side of things, you like units with easy integer fractions (12 inches in a foot is really easy to work with at human scale). When you come from the science side of things, you like easy decimals and that's why metric wins there.
The UK used to be nominally 240V and a lot of EU countries used to be 220V, but we harmonised on 230V because it's comfortably within the tolerance bands for both. Nothing really changed in practice - UK installations still deliver about 240V and most EU installations deliver about 220V - but it was convenient to have a common standard.
It used to be the continent used 220V, and the UK used 240V, until we standardized on 230V.
The UK defines this as 230V -6% +10% (i.e. 216.2V – 253.0V), and nominal supply is 240V
The continent defines this as 230V -10% +6% (i.e. 207.0V - 243.8V), and nominal supply is 220 or 230 by region.
We called this harmonisation - in reality it's more like agreeing to disagree. We just fudged the tolerances until everyone was happy.
(To put some context around this - most sites don't receive nominal supply. The actual voltage delivered depends on your distance to the local substation. Typically they over-deliver such that sites closest are a little over, sites furthest are a little under. If they actually delivered ±0%, sites at the edge of their network would be further from nominal. So end-user equipment should be built to expect variation.)
That'd give an upper bound of 243.8, which is far too close to 240 to be practical. As I tried to add, there is some necessary and natural deviation from nominal to account for path loss etc. 230±6% only allows 240 to deviate by 1.5%, which isn't much scope at all.
I believe ±10% was the traditional definition, so they just trimmed a little off the top end so it strayed less from Europe's definition - but not enough to actually affect nominal distribution.
i wish 240V was more common. i can't charge my EV at a reasonable rate and it would cost me $15k+ to install a 240V in my detached garage (requires trenching).
How does ChatGPT come anywhere close in usefulness compared to the breadth and fan-out of facts, opinion, supports and counter-arguments offered by this format?
I am european. Regarding to the metric system, IMO americans are wrong. But regarding to electricity, americans have it better than Europe: France, UK, Italy, Switzerland, Denmark and Germany have their own sockets, and that after a recent spread of the german Schuko. We shouldn't lecture americans about changing things to use a standard.
I spent about a decade in Europe and really enjoyed learning about how their electrical grid works. The ability to directly plug most appliances without needing to buy extra adapters was amazing. Boiling water also took half the amount of time.
If memory serves, Thomas Edison used a 110v DC power supply to create a system of electricity for people. Meanwhile, Nikola Tesla invented the three-phase 240v Alternating Current (AC). Tesla was clearly a man ahead of his time (even by today's standards).
tldr; Europe's grid is vastly superior to America's.
“The ability to directly plug most appliances without needing to buy extra adapters was amazing” unless you live in Italy, Switzerland, France (they have a socket with the ground sticking out I think), Poland, the UK, Denmark… it’s getting better and better due to the use of DC and the reduced need for grounding, though
I would like the voltage to be lowered even more, to 70 Volts. The reason is that 240V is very dangerous and can easily kill a human. But it seems governments care only about saving aluminium in wires rather than lives.
> But it seems governments care only about saving aluminium in wires rather than lives.
I go even further on trying to save aluminum in my wires by not using any aluminum wires. Aluminum wiring is pretty rare in the US and largely considered a nightmare to work with.
> Aluminum wiring is pretty rare in the US and largely considered a nightmare to work with.
Yeah, you basically only find aluminum wiring used today for the feeder, and for circuits larger than 60A. And that's mainly due to cost, copper is pretty expensive.
> But it seems governments care only about saving aluminium in wires rather than lives.
That's needlessly inflammatory. Both the US and UK governments have numerous electrical standards and regulations designed to keep people safe despite unsafe power levels in residential wiring. You might argue that they aren't doing enough in this regard, but to say they only care about saving metal just isn't true.
I moved from the US to Singapore which uses 230, and that coupled with the humid environment makes things a lot less unsafe. That plus old HDB electrical work isn't always the best. Getting shocked and damaging electronics because a socket is lose is very common here, and can be life threatening. I never had to worry about this (at least as much). Floating ground here on the other hand is device or even life threatening which is a real issue as most chargers especially recent GaN ones do NOT have a ground prong.
I’m really interested to hear more details about how this is possible, because it’s scary but fascinating!
Here in Australia we have 230V, and getting shocked is not at all common - we have very strict electrical standards for both installations and devices, residual current devices (GFCI equilivalents) now required on every single circuit, everything either has a proper ground or is double-insulated (unlike the US sockets here without a ground pin are very uncommon because you can’t plug a lot of devices in to them) etc.
There was a possibility where you could pull the plug out very slightly and slide something like a knife in between the plug and socket and touch the active and neutral pins, so the standards were changed many years ago now so compliant plugs now have insulation on the live and neutral pins for the first half of their length (see an example plug here - https://au.rs-online.com/web/p/power-cords/0321168 ).
this is not an issue in Europe. what kind of plugs do you use in Singapore? the EU plug doesn't let you get shocked when pulling the cord. i am willing to bet it's because of that, not because of 220 vs 110. it has never been an issue in my life and i don't get shocked ... ever.
after a quick research, i think it's the socket not the plug, it's easier to touch the live wire if the socket is flat.
edit: can't reply to the child comments, maybe there's a time limit, i'll answer here. i have no experience with the british plugs, if you say it's impossible i believe you. i don't understand, though, how does this happen to the person from the top message.
There's a long earth pin on the top of British plugs, the socket doesn't open the holes to allow the other two pins in until that's already inserted to the appropriate depth. So you can't stick anything in to the socket and touch a live wire.
You absolutely can. I've personally be accidentally shocked twice by pulling a firmly inserted plug out of a socket, but it was my own fault. Get the plug partly pulled out then readjust your hand to get more grip around the side of the plug and in doing so accidentally touch the non-insulated section of the live prong just as it is in contact with the live terminal
If both the plug and socket are correctly made, it's physically impossible - by the time the contacts on the plug are exposed, they've disconnected from the contacts in the socket. No matter how much you prod and poke, you should only ever come into contact with an insulated sleeve or a non-energised contact. Unfortunately there are a lot of non-compliant plugs being sold by disreputable online retailers.
It is possible to get a very mild shock from the plug contacts if the input capacitors of the appliance haven't fully discharged. This shouldn't happen with properly-designed appliances, but it's very unlikely to be dangerous if it does happen.
You should not get downvoted for this. The whole world isn't as safe as Europe. I spent time in a country with 220V, and in those days there was virtually nothing preventing you from getting shocked (I know as I've been shocked). The prongs were round, and you could easily touch the metal while inserting and get a shock.
Another problem: Some of the plug/socket combinations were fairly loose. It wasn't a tight fit. So if you're ironing, it was not unusual for the plug to be partially out of the socket.
(edit: this comment is quite useless, I need to leave it to keep the discussion understandable)
Interested in the answer which I don't have.
That said, UK is wired to the continent, which runs at 230V, 50 Hz.
Everyone runs at the exact same frequency (same fluctuations) at any moment across the whole continent for technical reasons. (edit: UK is actually not synchronized with the continent, I didn't know that either).
I guess having the about the same voltage as the rest of the continent is at least convenient (edit: apparently it's not exactly the same?).
So I guess the question is US vs the European continent.
Curious about the rest of America (North and South).
North America is generally on 220-240V split phase with NEMA compatible plugs. In Mexico, the plugs are often ungrounded and only compatible, not identical to NEMA. In my house in the US I have mostly 120V circuits with a few 240V for appliances.
Brazil is a bizarre mess of 127V single phase in most of the south and 220V single phase in the rest. They are supposed to use euro-style grounded receptacles but often have installed euro and NEMA bi-compatible plugs at 220V or 127V. A lot of 220 circuits only carry 8-10A.
Argentina uses the Australian style receptacle with 220V 50Hz.
I'm not sure about the rest of South America but I think Uruguay and Paraguay are compatible with Argentina and the rest are on 60Hz and generally 220V.
I'm surprised nobody mentioned Japan, and its varied system.
As to why split phase.... I am not really sure. Really, I wish a three phase residential had become normal instead. All the advantages of split phase but now your motors don't have to suck. I have heard a three phase residential connection is common in some parts of Germany, lucky bastards.
One interesting side note is how the US last mile distribution layout is different than germany. The US uses a lot more smaller transformers, really one per street. while germany uses fewer larger transformers, one per neighborhood. not sure which one is better I bet the german layout is more efficient. but I will note it is a lot easier to keep spares and change out a small transformer.