Re: Power supply question 240volt 3phase power vs 1 phase

Quote from: philipma1957 on April 14, 2015, 05:09:11 PM

these would have 2 hots and a ground each hot would be a 120 if you went hot to ground. but if you go hot to hot you get 240.
if measure his power and get that result it would be more like 1 phase.
your description has me a bit confused maybe his shop wiring is doing what you say if I understand you correctly 3 hots feed into his shop.
and each 3 prong twist plug he has is using 2 of the 3 hots.
So if I want to load balance. with the 3 hots named 1 2 3

I make 3 receptacles

1+2+g is the first plug
2+3+g is the second plug
1+3+g is the third plug

each one does a evga 1300g2 running at 1000 watts and we are load balanced

^that sounds correct. Thats a 30A receptacle, meaning you can load 5.5-6kW on it (208 and 240V respectively, achieving 80% load). It would connect to your breaker panel using a 2-pole breaker (plus GND)

Now if you have a 30A 3-phase, thats a bit different and is quite unlikely to be seen in a residential building. (90% of homes are 2-phase, each at 120V, to allow 240V when running both phases). A 3-phase breaker will only work properly on a 3-phase panel - on a 2-phase panel you would have 2 rows of 240V sockets, and one row of 0V (since its 2 hot lines of the same busbar)

3-phase is generally for industrial, where power is stepped down from a 600V service, giving 3 hot lines, each at 120V or with a difference of 208V between any two lines. You should balance the load across the three phases