What is the maximum load on a480/277, 3 phase, 4 wire panel with a 20 amp, 2 pole circuit breaker, is there a chart that I can use, using different voltage systems? What is
The rule of thumb if you need to go to the next higher CB rating?

A 20A breaker can handle a load of 20 amps. The voltage is incidental.
You go to the next higher breaker when the load is too much for the circuit. Many commercial circuits are considered a continuous load so that you can only load a circuit to 80%.

What is the basis of your question? What is the application?

3 phase, 2 pole?

Are you trying to calculate load on the entire panel, or just the 20 amp circuit?

Single Phase VA (Volt-Amperes) = Volts times Amps for the two pole circuit.
Three Phase VA (Volt-Amperes) = Volts times Amps times 1.73 for the panel.


What is the maximum load on a480/277, 3 phase, 4 wire panel with a 20 amp, 2 pole circuit breaker, is there a chart that I can use, using different voltage systems? What is
the rule of thumb if you need to go to the next higher CB rating?

There are no charts, we use Ohm's Law calculations.

There are no "rules of thumb", we use the National Electric Code.

Answer Stan's questions to get better answers.

Sure,:

3 phase, 2 pole?

Why not? A 480 volt single phase load can be supplied by a 3 phase panel.

A 20A breaker can handle a load of 20 amps. The voltage is incidental.
You go to the next higher breaker when the load is too much for the circuit. Many commercial circuits are considered a continuous load so that you can only load a circuit to 80%.

What is the basis of your question? What is the application?


I am trying to learn how to fill out a 480/277v, 3p, 4w panel. I have a load of 5425/phase.
Is 20a-2p cb good?

Also, how do you convert kw to kva using 80% P.F.
Thanks a lot guys. :)

Do you have a 3 phase load or a single phase load?

5425/phase generally indicates a 3 phase load.

And your talking about 2 pole breakers or say a 480 single phase load.

277 I'd have to do some research.Not sure if they are 2 pole or single pole breakers.

80% pf means multiplying by 1/(0.80) or 1.25