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January 19

220 volt power, US vs EU

US households typically have 220V 60hz power for a few large appliances like stoves and clothes dryers, and 110vac 60hz for smaller stuff. EU, I believe, uses 220v 50hz for everything. Are the two 220V systems mostly compatible other than for a few frequency sensitive things? Like if I had a European vacuum cleaner and a suitable plug adapter, could I use it on US 220 volt power?

Also (I'm not actually in the market for this, just asking on general principles), in the US, what comes after 220 volts? Like if someone wanted, say, 40KW of power at home (say for an electric car charger), what voltage would it likely be and could a normal residential electric utility supply it without too much hassle? Thanks. 2601:648:8202:96B0:0:0:0:313A (talk) 03:45, 19 January 2021 (UTC)[reply]

The nominal standard voltage is actually 230 V in the EU and 240 V in the US, but that's not enough difference to matter. However, appliances in the US that use 240 V are actually supplied with two opposite phases of 120 V each, and work off the difference. This means both wires carrying the current are "hot" (live) at all times. Normal appliances in both the US and the EU are often designed so that the "hot" wire only runs from the plug as far as the power switch, reducing the chance that you get an electric shock if there is a short-circuit somewhere in the device leading to an external part you can touch; and this design is likely required by electrical standards. So if you have a 240 V outlet in the US and use a suitable plug to connect your European vacuum cleaner, it should run fine, but there will be a small risk of electric shock in case of a defect, and if your insurance company finds out what you did, you might lose your coverage.

As to the second question, as far as I know household power supplies never go above 240 V, but you can get 48 kW at that voltage if you have 200 A service, and maybe that's not the limit. I believe industrial users can get electricity at 415 V or 480 V. Electric transit vehicles in my city use 600 V. --142.112.149.107 (talk) 06:11, 19 January 2021 (UTC)[reply]

European plugs like the popular Schuko (but not the British or French plugs) are often non-polarised, so you don't know which of the two wires is neutral and which is hot (the earth wire, if present, is of course earthed). Devices get designed so that they are safe for either wire being hot. And although most neighbourhoods provide 230V in 3-phase Y configuration, there are some older installations that provide it in delta configuration (saving one conductor), so that all wires are hot. By using the 230V 3-phase Y-connection in delta configuration (so putting the device between the phase wires, not between phase and neutral), you get 400V (i.e., 230 times the square root of 3). If that's not enough (for example, you want to run a big supermarket or small factory), you have to apply for a direct connection to the distribution grid at about 10kV. PiusImpavidus (talk) 10:48, 19 January 2021 (UTC)[reply]

And don't forget that the above talk mostly about Voltage. Power is Voltage * Current, so you can get lots more power by using your existing Voltage at a higher Current. Usually that requires activity from the electricity supplier. Perhaps a new (thicker) building supply cable. -- SGBailey (talk) 15:05, 19 January 2021 (UTC)[reply]

Yes there's a practical limit to how much current an outlet can supply without needing prohibitively thick wire, enormous switches in the load device, etc. That may be in the 100s of amps but it's not in 1000s of amps, for most purposes. 2601:648:8202:96B0:0:0:0:313A (talk) 21:22, 19 January 2021 (UTC)[reply]

Thanks all. It is interesting to hear that EU households get 3-phase power. Does that mean their refrigerators can use 3-phase motors instead of the stupid capacitor start motors with a huge turn-on surge like we have here in the US? Do they actually do that in practice? I dunno but it sounds really cool to have 3 phase power at home. Things like computer power supplies could be a lot smaller. 2601:648:8202:96B0:0:0:0:313A (talk) 21:22, 19 January 2021 (UTC)[reply]

In the home, we use 380 V for stoves and ovens. 220 V for everything else. You probably won't find more than a handful of 380 V outlets in the average house. I don't remember ever seeing a 380 V computer power supply, but I presume that 380 V refrigerators exist for industrial use. 93.136.22.227 (talk) 23:03, 19 January 2021 (UTC)[reply]

Very very few UK private residences have 3 phase power. 3-phase is buried in the street and neighbouring houses are given the "next" phase in sequence. I know of one engineer who was seriously into power supplies as a hobby and he eventually had a 3-phase supply installed to his garden shed. -- SGBailey (talk) 09:36, 20 January 2021 (UTC)[reply]

Most houses have it here in Croatia. At least the ones where I looked, including the one I live in. They look like this. 93.136.147.244 (talk) 04:18, 21 January 2021 (UTC)[reply]

I've never seen a 3-phase wall outlet in a home. I've seen them at university or in commercial buildings. It is common to have three circuits, each supplying power to part of the lights and wall outlets in the house, each fed from one of the phases from the 3-phase supply with its own circuit breaker. Large consumers (stoves, ovens, electric car chargers) and producers (solar panels) may be permanently connected to the 3-phase supply.

This isn't really standardised within Europe. In the past many regional (city, province) utility companies made their own standards, which changed with mergers and technological progress, and installations rarely get modified to follow modern standards. With these technical matters, you often see three loose de facto standards within Europe, a British standard (UK and Ireland), a French standard (France, Belgium, sometimes Italy, Spain and Switzerland) and a German standard (rest of Europe). PiusImpavidus (talk) 10:15, 20 January 2021 (UTC)[reply]

In Paris, France I get only single-phase (230V) supply to my general circuit breaker. I am not aware of anyone who gets triple-phase at home (though it is not a common topic of conversation either). According to this (fr) it is possible to request triple-phase supply, but it is rather more common to ask a conversion from a legacy triple-phase installation to single phase.

It is true that some appliances are compatible with triple-phase 400V. For instance, this oven+cooking plate I have at home; page 18 of the manual indicates how to do the electrical wiring either with 400V or 230V (if you are an amateur electrician you probably do not need to read French to understand it).

Frankly do not really see a case for triple-phase in dwellings, unless you are forced to (residential contracts with max power above 18kW require triple-phase, I assume because of wire cross-section constraints, but that is already quite a lot of power for a home). If you split the phases at the circuit breaker, you have a few headaches at that place (balancing the phases, setting up three differential circuit breakers) and the rest behaves as a single-phase installation anyway. If you keep triple phase through the home, you need non-standard plugs and one more wire on each line (with a lower cross-section each, but your main cost of wiring is going to be the electrician's time, not the mass of copper). Yes, you get induction motors without a current spike, but motor-graded fuses exist (the ones that can take an initial spike of current above their nominal grading - in France those are called AM for "accompagnement moteur" [motor support] and the spike can go up to 7x the nominal). Tigraan^{Click here to contact me} 11:57, 20 January 2021 (UTC)[reply]

Long story short: no. The U.S. stuff is split-phase power. The 240V nominal is across both hots. A non-U.S. applicance will be designed for either hot-to-neutral, or some other scheme with different voltages. This is not safe to just try to hook up, and you will also have problems with anything other than an AC motor. And yes, 240V split is generally the most you'll be able to get hooked up at a typical U S. residence. "Fast" electric car chargers for residences work off this. Some rural service provides higher voltages and multiple phases, intended for farm equipment. --47.152.93.24 (talk) 05:07, 21 January 2021 (UTC)[reply]

Thanks everyone. 2601:648:8202:96B0:0:0:0:313A (talk) 08:04, 22 January 2021 (UTC)[reply]