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IF the nomenclature plate on a piece of 220VAC equipment says 10.0 Amps, does that mean that the load is 10 amps per leg, or 10 amps total, therefore 5 per leg?

  • there is no leg ... whatever current flows out one wire, it has to return through the other wire ... that is how an electric circuit works – jsotola May 14 '18 at 17:48
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    220V draws from both legs, so 10 per leg. There'll be no current flow on neutral. It won't even be connected. – Harper May 14 '18 at 17:55
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If you put a current meter one leg, it reads 10A; if you put it on the other leg, it also reads 10A. But that does NOT mean there is "20A" in the circuit. The current in the two wires is not additive. Current flows from one point to another through the CIRCUIT, and the circuit consists of those two wires.

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The confusion is not the amperage. The confusion is how much power do you have. For the record a 10A 220V circuit will have a minimum 10A/2 pole Breaker.

In the USA a 110v, 10A circuit will pull 1100VA. A 220v 10A circuit will pull 2200VA, twice as much power as the 110v circuit. Technically on a 220v that is connected to 2 phases there is no return. That's as simple as I can make it for a DIY'er. Otherwise we need to get into a course on phase relationships.

  • 220-240v in the U.S. is 2 legs of a single phase. The 2 legs come off the transformer and have a center tap (the neutral) each leg to neutral is 120v or 240 leg to leg. If it were part of a multi phase phase system the leg to leg value would not be the same as adding each leg to neutral voltage. – Ed Beal May 15 '18 at 16:58
  • @EdBeal - You are correct but what does that have to do with the question or the answer? Or should I edit it to say I don't want to get involved in electrical AC theory? – Retired Master Electrician May 15 '18 at 17:36
  • Your answer states 2 phases and I was clarifying as many call 220/240 as 2 phase and it is not. This is the reason I made the comment. – Ed Beal May 15 '18 at 18:26
  • Answer seems way out in left field – Kris Jul 17 '18 at 18:32
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10A in one hot, 10A out the other hot

A 240V-only piece of gear connects to two hot legs and a ground (no neutral), so if it pulls 10A, that 10A has to be going in one hot leg and out the other hot leg -- there's nowhere else for it to go! (In other words, it draws 10A, period -- the legs do not "add together".)

  • Not a very well explained answer. – Kris Jul 17 '18 at 18:31
  • @Kris -- I added a bit more explanation – ThreePhaseEel Jul 17 '18 at 22:17
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It means 10 Amps in parallel.

That is both legs pull 10 Amps, but because they're in parallel they never exceed 10 Amps. The meter would read both legs when measuring kW

Edit: I made a drawing to help visualize. (using 20A load instead of 10A)enter image description here

  • This is very confusing. Are you suggesting 4 wires - an “out’ path and a “return” path on each leg? On a US 220 v circuit, the breakers are in series and there are only 2 wires involved. – Mark Aug 3 '18 at 20:28
  • The runners alternate from the source to the load. That maybe where you're getting 4 wires, but only two. Yes, a 240v load is basically a simple series circuit with each winding 180 degrees opposite in polarity to give a parallel source of power. – Kris Aug 4 '18 at 3:37
  • Also the current in is equal to the current out. This is why I drew two runners per ungrounded conductor – Kris Aug 4 '18 at 3:42

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