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Board Hardware
Re: Power supply question 240volt 3phase power vs 1 phase
by
philipma1957
on 16/04/2015, 15:40:36 UTC

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


I got 2 phase in house and finally did 2 circuits into 240volts.

My friend  with cheaper power has ' 240 volts 3 phase'  and runs a lot of heavy machinery in his shop..   those quotes are what he told me.

When I go back to his  place I will bring a meter and figure out what he really has.

In my home the one I wired with 30amp 2 pole breaker to a 30 amp plug is 10 gauge a 35 foot run.  What can 10 gauge handle safely?

  The pdu is fused for 24amps.

   I know 12gauge is okay for a 20amp 2 pole 240 volt.

Is 10 gauge okay for a 30 amp 2 pole 240 volt.  1 single 240 l6-30r plug to a 24amp pdu.  TIA