Why does the USA use 110V and UK use 230-240V? (2014) | Hacker News Reader

Why does the USA use 110V and UK use 230-240V? (2014)

electronics.stackexchange.com

207 pointsdilawar743 comments

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).

Seems to me that the tradeoff is worth it.

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.

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.

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.

Transmitting same amount of power at higher voltage requires LESS copper.

On the contrary, more phases = less copper.

Example of appliances: HVAC, induction heaters, boilers, car chargers, solar panels inverters, ...

> ...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...

> 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.

> 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.

Three phase and high voltage are both more copper-efficient.

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.

Resistive dryers aren't common in Europe; they are mostly condensation dryers which use much less electricity.

inverter technology is always an induction motor. No one runs an inverter to run a universal motor.

You do realize that the grid runs at a completely different voltage than what is actually delivered to standard residential service, right?

It is entirely possible to get three phase, high-voltage power in North America, it just isn't run to individual houses unless specifically requested.

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.

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.

You can request it all you want in North America, but you probably won't get it. A three phase converter is way more likely.

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.

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.

[0] https://electronics.stackexchange.com/questions/625353/is-3-...

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.

—-

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.

I live in a house built somwhere between 1900 and 1930, and it's powered by 3 phases. Since deep commie era.

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.

I read it as 400v coming into the house, not coming out of outlets... Like 220v is coming into the house in the US.

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.

And given the US outlet design, I imagine people do come into contact with 110v quite frequently!

And it's a good thing that 110v is safer because American electrical safety standards are appallingly bad.

Here are the motor loads for a typical residence:

-1/2 to 3/4 HP furnace fan - 3 to 5 ton AC unit

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.

Why are AC units measured in weight?

> No matter how you put it, the US residential power grid is conceptionally lagging.

Not just conceptually == reliability is lower than that of its peers: https://www.statista.com/statistics/268155/ranking-of-the-20... (if you don't have a statista account, US is at the bottom of this list at 98.6)

State level data: https://www.eia.gov/electricity/data/eia861/

I don't believe any country can have 100% reliability, so the data is suspect.

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.

UK scored a massive own goal and are no longer part of Europe ;)

> Really all modern residential connections in Europe are 400V three phase electric power

Not the case in the UK.

Three-phase power supply for residential use is common even in India.

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.

https://www.subzero-wolf.com/assistance/answers/wolf/common/...

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.

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.

It's just increasing the power draw. There is no concept of 'stealing power from another phase'

> solved thet by running the lighting on 220V with sets of two 110V bulbs in series

Sounds like an exciting day when one of your bulbs burns out!

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.

Why? A burned-out bulb fails open not closed.

If it failed closed then a bulb burning out would trip the circuit breaker.

If you want exciting look up floating neutral.

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.

Nice over-provisioning; I doubt the gas shortage or electric cars were on the radar when 3 phase became the norm...

How are loads balanced to phases in a standalone house?

Usually the circuit breakers are sequentially assigned to phases with wiring blocks [1].

In the end load more or less averages out across all the individual grid users.

[1] https://www.zaehlerschrank24.de/phasenschiene-kdn363f-3-poli...

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.

[1] https://www.eia.gov/todayinenergy/detail.php?id=54639

[2] https://neon.energy/Neon_Data-quality_European-Commission.pd... (22nd page, figure 5)

They may be rare but I’ve witnessed or been within a block of two transformer explosions and one wire melting in the USA.

Yeah near me they rarely ever pop, and when they do it's almost always lightning related.

> 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.

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.

The transformer likely served the houses further down the block - yours was served by one upstream.

It isn’t terribly hard to track it back if the wires are above ground.

Depending on where you live, they age out too. The one behind my house exploded a year or two ago.

It was manufactured in 1959!

> I have heard a three phase residential connection is common in some parts of Germany

Over here (large country in South Asia) it's three phase by default.

You can get single phase upon request, provided it's a really really small house, shop etc.

> large country in South Asia

It sounds like a crossword puzzle. :)

> I have heard a three phase residential connection is common in some parts of Germany, lucky bastards.

Not some parts. It's common in all parts of Germany - and I think even common on the whole EU.

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.

There are tons of people who have garages with table saws, air compressors, etc. that would benefit from 3 phase power.

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.

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]

[1] https://de.m.wikipedia.org/wiki/SN_441011

[2] https://hager.com/de-ch/katalog/produkt/wh22730700k-ka-eb-st...

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.

I thought residential US service was 240V split phase with two 120V legs.

I've heard for some wet construction locations they'll set up 120V split phase with two 60V legs, to keep the potential to ground smaller.

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.

I suppose in nearly all of Belgium 3 phase + N (230/400V) is common. You have to pay extra but it's available.

Three phase residential connection is also common in India (at least some bigger cities).

Could I run a standard computer PSU of 220V split-phase?

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.

At current rates of ballooning power requirements we will soon have to

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!

Yep, most of them are a few percent more efficient at 240v too and have higher maximum power output... I run all my always-on computers that way.

Generally anything that has an IEC power connector will support running at 240v (but beware, you may need to flip a switch).

Most switching power supplies won’t care

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.

I stand corrected and added a disclaimer in my original comment. Thanks for teaching me something I assumed incorrectly.

Same in Canada, though with 600V 3-phase instead of 480V, mostly.

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.

You are also mistaken about the configuration in Europe, since the 3-phase system has 400V between the different phases and 230V to neutral.

Nobody's pointed it out yet, so I'll mention it:

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.

220, 221, whatever it takes.

Humor is often not well received here.

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.

https://electronics.stackexchange.com/questions/614270/why-d...

Japan uses 100V and 50/60 Hz depending on where you are in the country.

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.

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.

Sure, but the nominal value is still 120 V.

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.

I learned recently that Japan is often on 100V power so I'd think a lot of international components would support 100-240V.

It's mostly just a misnomer. A 110 V device with a 5% tolerance, for example, would not work on nominal US circuits.

While it's true, the US does supply 120V±5%, appliances and equipment are operable on a much wider range.

For example, my laptop charger is rated for 100-240V, which is not uncommon.

120V-5% is still greater than 110V.

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.

Technically they function fine as low as 95V for the worst case scenario, if they're well built.

That's a fairly recent development, mainly limited to switchmode power supplies.

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

100-240V 50-60Hz switching supplies are common "worldwide" or "universal" adapters, definitely not an indication of service voltage standard here.

The 100V low end is there due to Japan.

110V is the Room Mean Squared (RMS) voltage.

https://www.electrical4u.com/rms-or-root-mean-square-value-o...

No, 120V is the nominal RMS voltage; the peak is 120V*sqrt(2)≈170V.

The *root mean square is 120V.

As a Brit, the best thing about 230v is being able to run a 3kW kettle to make my tea. I took this for granted until I moved to the US.

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?

According to Twinings tea:

Always use freshly drawn (filtered if possible) cold water in the kettle. Tea loves oxygen as it helps the flavour develop.

Most of us are guilty of the following... looking at the kettle seeing there is some old, used water in there and simply re-boiling.

If you keep re-boiling the water in the kettle, it loses all of its oxygen and you’ll be left with a really flat cup of tea.

If you boil the kettle with fresh water, you’ll have a delicious cup of oxygenated tea that tastes divine.

https://twinings.co.uk/blogs/news/how-to-make-a-cup-of-tea-p...

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.

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.

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.

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.

>Why don't Brits (and other tea drinking cultures in Europe) do this?

Because it is better to boil the right amount of water to the precise temperature when you need it, as it takes virtually no time.

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.

I’ve had a 4L Zojirushi boiler in the US for about 15 years now. This is the best solution for those who complain about 120V kettles.

Legionella

I kid, but there's something about "fresh" water probably?

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.

It does seem feasible to equal the performance of a 3 kilowatt kettle with batteries!

=-=-=

Question #1: Can we get 3 kilowatts of power out of some lithium ion batteries?

There are high-current versions of lithium batteries. Conveniently, they're widely available because they're used for vaping.

I found a battery that looks reasonable (https://www.18650batterystore.com/products/molicel-p42a). Its stats: 4200 mAh capacity, 3.6V nominal, 45A continuous discharge, and retail cost $4.99.

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.

Impulse Labs, a startup, is doing lithium-backed kitchen stoves. Claims to heat-up 1L of water in ~40secs. That's at least 8.6kW.

https://twitter.com/sdamico/status/1592553611879673856?s=20

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.

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.

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.

195˚ tap water coming from a dedicated tank is not a common American thing, in case someone is wondering.

> 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:

* https://www.ontario.ca/laws/regulation/r04023

An exception is given for dish— and clothes washer outlets.

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.

That sounds really dangerous. My hot water is set to 120°F.

Best appliance I've ever owned.

How many accidental burn injuries you or your guests have?

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 definitely notice the difference in speed between a Uk and US kettle.

In the UK I put the water on then while it’s boiling get a mug and tea bag and then the kettle is boiled very soon after.

In the US I generally wonder off as the kettle takes a couple of minutes longer.

If it took 15 seconds, you'd stand there and watch it.

Sometimes you need an emergency cup of tea

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.

Not worth it. A temperature controllable kettle that shuts itself off and can keep water warm is both incredibly convenient and far more safe.

TIL about the word "hob". Americans call it a "cooktop" or "stovetop" or "range"

How 1950s!

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.)

It’s called “TV pickup”, and Wikipedia has a good article explaining it, especially the bit about using pumped storage to meet demand in seconds.

https://en.wikipedia.org/wiki/TV_pickup

Tom Scott's video on this is interesting, as a side note.

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 :(

In the US it is against code to have any regular appliance use more than 15 amps continuously I believe

In theory you could use one of those Leviton British-style receptacles designed for US-style boxes on a dedicated 240V circuit.

In practice, NEC code likely prohibits you from doing this.

Just get a Japanese-style hot water boiler. They're way faster.

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).

Have a look here: https://www.diydoctor.org.uk/projects/cablesizes.htm

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...

> 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).

If you want a deep dive this video made by a British electrician is worth a watch https://youtu.be/hZN6hiGLtrE

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.

We have ring circuits, which are typically on 32A breakers.

  > 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.

And yet people have 36kW water heaters and they can't boil the water!

https://www.homedepot.com/p/Rheem-Performance-36-kw-Self-Mod...

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.

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.

Those electric kettles in the US boil water _really slow_ when one is used to 230v.

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.

With induction stoves getting more popular that’s less of an issue nowadays.

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.

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.

We have an induction stove too and it's great. But the kettle is still significantly faster at boiling water.

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.

There's no chance I'm bothering with getting out a stovetop kettle every time I want a tea. Far easier to just have a separate kettle

Still, putting the stove on to make a cup of tea seems wrong.

https://www.youtube.com/watch?v=_yMMTVVJI4c

The difference is 2 minutes on the boil time of 1L.

From the article:

> 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.

It's not 230, it is 240!

3000 / 230 = 13.04

3000 / 240 = 12.5

We fit 13A fuses to the plugs of kettles. At 230V the tolerance would be too close.

Whereas in reality, a kettle designed to be 3kW at 240V would only be 2.755kW at 230V, or 2.520kW at 220V.

You'll often find the latter pair of number printed on the base of the kettle. i.e. 2520-3000W at 220-240V.

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.

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)

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.

Obligatory TechnologyConnections reference - https://www.youtube.com/watch?v=_yMMTVVJI4c TLDR: in US it takes 2 minutes more :). Is that difference that noticeable IRL?

If you were British, you would not need to ask this.

Being compelled to wait two minutes more to boil a kettle for a cuppa would be enough to provoke an armed rebellion.

Not even sure I'm kidding.

Well you have to remember the UK is the nation that fit kettles in Tanks

https://en.wikipedia.org/wiki/Boiling_vessel

This is one thing I really liked when I visited Europe.

Kathy Loves Physics & History did a video on this, and the reason is basically legacy:

* https://www.youtube.com/watch?v=7yRGvMgieEU

Edison originally purchased others' dynamos, especially Wallace-Farmer, which was 110V (DC):

* https://americanhistory.si.edu/collections/search/object/nma...

* https://en.wikipedia.org/wiki/Moses_G._Farmer

So Edison's long-legged Mary-Ann was also 110V:

* https://www.collectorsweekly.com/stories/82967-thomas-edison...

* https://edison.rutgers.edu/life-of-edison/inventions?view=ar...

* https://americanhistory.si.edu/collections/search/object/nma...

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).

50 Hz is about a G, and 60 Hz is about a B-flat. Video comparison: https://youtu.be/pMtn-loUrg8

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.

https://www.youtube.com/watch?v=bWxS2njU-JI&t=355s

There were many factually correct, and even historically interesting responses. But not a single response answered the question.

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.

> Both 110V and 230V are reasonable choices.

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.

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.

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.

(from the wiki: https://en.wikipedia.org/wiki/Electrical_wiring_in_the_Unite...)

  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.

There is not one single all encompassing answer.

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.

"Edison's lamps were 100V" is in one of the answers.

Do you know the answer? (Of course your remark makes sense even if you don't, but, if you do, then I'd love to know.)

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.

Welcome to *.stackexchange.com

Relevant Technology Connections video: "The US electrical system is not 120V" https://www.youtube.com/watch?v=jMmUoZh3Hq4

Some devices can also be more efficient when using 230V. Eg: PSUs

https://electronics.stackexchange.com/questions/469913/compu...

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.

> I've given up on determining the winner

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.

There is no winner. It's a simple API, with many correct answers. The US ossified on it's system, and different European countries did the same.

It's just a standard "Emacs vs VIM" flamewar.

> The US ossified on it's system

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.

Well if you compare it to emacs vs vim, that's making me think there is a correct answer.

Tom Scott has a fun video not on voltage but on the merits of the wall sockets them selves:

https://www.youtube.com/watch?v=UEfP1OKKz_Q

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.

> why the US never switched to metric

Pretty much exactly why the UK didn't.

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?

The tradition answer to this question is surely this wonderful Tom Scott video: https://www.youtube.com/watch?v=UEfP1OKKz_Q.

> cumbersome over-designed

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).

> It's a pain they are not the same as the rest of Europe, but what is cumbersome and over-designed about UK plugs?

The size is definitely cumbersome. Look how much bigger they are than US/EU/AU plugs, basically any other countries plugs.

I'd call having a fuse in the plug itself over-designed.

> Follow up question, why Swiss plug needed to be so close to the rest of Europe, but different anyway?

I have the same question about AU plugs. Literally the same as the US plugs (newer ones that don't have one side larger at least), just at an angle.

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.

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.

> They can be annoying to travel with

That's my main problem since I travel a lot, or used to at least.

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.

> Some European houses even have a few 3-phase 380V outlets for heavy duty equipment, which would be exceedingly rare in the US.

My European 50m² apartment has two.

In the US, you can have electric receptacles in bathrooms. In fact, code requires it. You can plug in 120V electronics and appliances no big deal.

In the UK, this is not allowed because 240V is not a good idea in bathrooms.

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.

[0] - https://www.youtube.com/watch?v=_yMMTVVJI4c

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.

>Why do they use different frequencies like 50Hz, 60Hz?

I've never found a technical answer for the 50Hz vs 60Hz question. It does seem to be an arbitrary standard.

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.

TIL UK (or EU) uses 230V, not 220V like my country.

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.

UK actually uses 240V, which happens to be within +10% of 230V.

Po-ta-toe - po-ta-toh. You can use 220V stuff with 230V plugs. There are fluctuations for each network, anyway.

Which country are you talking about?

In The Netherlands the allowed voltage tolerance is 10% by law. So everything between 207V and 253V should be fine. And we also had 220V until 1989.

"In some rare situations 220V might be more dangerous to touch."

Uh huh, here's an idea, go ahead and test that out for yourself!

And with 30mA GFCIs, the risk is greatly diminished

Old joke: why USA use 110V and UdSSR 220V? Answer: because half of it will be stollen in transition anyway.

Even stranger than that, Japan has two grids, one at 50Hz and one at 60Hz!

...which were completely isolated, until Fukushima led to power shortages so they hurriedly linked /are linking the two with DC interconnects.

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).

Could you do the trenching yourself?

I don't know where you are, but in the US a walk-behind trencher rents for under $500 per day [1] [2] [3] [4].

[1] https://www.sunbeltrentals.com/equipment-rental/earth-moving...

[2] https://www.compactpowerrents.com/rental-equipment/trencher/...

[3] https://www.compactpowerrents.com/rental-equipment/trencher/...

[4] https://www.compactpowerrents.com/rental-equipment/trencher/...

>i wish 240V was more common

More common where? Your main service panel is 240V. Do you only have a single 120V circuit feeding your garage?

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?

Because, Freedom. And, because America. **===

Now, I'm going to go talk to My Fellow 'Mericans about continuing to not use the metric system.

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.

similar story to railroad gauges

(2014)

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

There’s a special plug for the oven, no adapter needed.

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.

> 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.

Death by electrocution is incredibly rare in the EU, what are you talking about? Data, or hold your peace.

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.

edit: after a quick research i thing the reason is the socket: https://www.everyworks.com/reasons-why-your-singapore-electr... we don't use this, we have a small hole inside ours and it's impossible to touch the live while the plug is connected

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.

> that coupled with the humid environment makes things a lot less unsafe

Safer? Why?

Getting shocked is a symptom of faulty electrics, not of using 230V (even in a high humidity environment).

(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).

The uk grid is not synchronized with the european grid, it is just HVDC interconnected.

You are right about the european grid, it is synchronized

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.

UK interconnections to the continent are via HVDC links; the UK grid is not synchronous with the continental grid.

It's almost North America (and some friends) vs rest of the world, really:

https://en.wikipedia.org/wiki/Mains_electricity_by_country

Picking a small point from your comment I find interesting, the voltages vary considerably across Europe depending on all sorts of factors.

In the UK at least it's from around 216 to 253 volts. Mine is sitting at 249 now.

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