Ask Experts Questions for FREE Help !
Ask
    Tonylac's Avatar
    Tonylac Posts: 2, Reputation: 1
    New Member
    		  
    #1

    Mar 27, 2009, 03:14 PM
    Maximum VA load on a 20 amp CB
    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?
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
    Electrical & Lighting Expert
    		  
    #2

    Mar 27, 2009, 03:40 PM
    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?
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member
    		  
    #3

    Mar 27, 2009, 07:49 PM

    3 phase, 2 pole?
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
    Uber Member
    		  
    #4

    Mar 28, 2009, 02:55 AM
    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.

    Quote Originally Posted by Tonylac View Post
    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,:
    Quote Originally Posted by KeepItSimpleStupid
    3 phase, 2 pole?
    Why not? A 480 volt single phase load can be supplied by a 3 phase panel.
    Tonylac's Avatar
    Tonylac Posts: 2, Reputation: 1
    New Member
    		  
    #5

    Mar 30, 2009, 10:38 AM
    Quote Originally Posted by stanfortyman View Post
    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. :)
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member
    		  
    #6

    Mar 30, 2009, 11:32 AM

    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
Not your question? Ask your question View similar questions
 

Add your answer here.


Check out some similar questions!

Maximum load on 20 amp circuit breaker [ 14 Answers ]

I am aware of certain normal maximums. I guess I'm looking for somebody to tell me that I'm pushing things too far, or not. I want to hook up a portable air conditioner (Sunpentown WA-1220E) which is rated at 950 watts (and, mysteriously, at 9.0 amps) along with an HP 4Si printer, which is rated...

Kenmore front load washer won't agitate/spin if load too heavy [ 2 Answers ]

My Kenmore front loading washer, model 417.43042200, won't agitate or spin to complete the cycle if the load is too heavy, such as 5 bath towels. If I take off the back and help turn the drum in the agitate or spin mode it will agitate/spin and complete the cycle. The pump still drains the tub. If...

Maximum load allowed on a branch circuit used for fixed resistance heating? [ 1 Answers ]

What is the maximum load allowed (%) on a branch circuit used solely for fixed resistance heating?

Maximum load on 15A circuit [ 5 Answers ]

What is the maximum load in watts, that will blow a fuse on a 15 amp household circuit?

View more questions Search