|> We're in an industrial park where our space is supplied with 208Y/120 |> 3phase power. My understanding is that any phase taken to the fourth wire |> neutral gives 120V. And any phase taken to any other phase gives 208V. |> My question is about the amps available on any given phase - neutral |> (120V) connection. The service is 120/208@100A . Is it so that three |> feeds of 120V (A - Neutral, B - Neutral, and C - Neutral) would each be |> able to carry 100A? |>
|> I guess, in other words, what I am trying to ask.. is that from a 120V |> perspective.. is 208Y/120 @ 100A equivalent to three 120V @100 single |> phase circuits? |>
|> Thanks |> -M | | Yes. Each phase can provide 100 amps, regardless of whether you connect | loads as three-phase, single-phase line to line, or single-phase line to | neutral (or any combination).
That would be for one single phase load. Multiple L-N loads work out easy because you just add up the amps separately on each phase. It gets more complicated when dealing with a couple of L-L loads because the amps don't add straight on the common wire for the loads in different phases. If all the L-L loads are equal, you can run them up to 57.735 amps and will see the 100 amps on the actual phase lines. But as long as your loads are all just 120 volt, they are all L-N, and it's simple: you get 100 amps on each wire relative to neutral, and (short of harmonics or certain weird reactive combinations) the neutral balances out.