Power to Office Trailers

faresos

Senior Member
Hello everyone:

I have a situation where I need to power 5 office trailers located outside from the main building switchboard. The plan is to provide a 450A/2P (480V) in the main building switchboard to feed a new 167KVA, 120/240V, 1-Phase transformer located outside. My question is, does the 800A, 120/240V switchboard (located outdoor near the trailers), has to have a main circuit breaker if we are feeding 5 trailers? The current design show 6-breakers at 150A each plus future spaces. Are we limited the 6-disconnect (breakers) if we didn't have a main breaker?

Thanks,
 

jap

Senior Member
Hello everyone:

I have a situation where I need to power 5 office trailers located outside from the main building switchboard. The plan is to provide a 450A/2P (480V) in the main building switchboard to feed a new 167KVA, 120/240V, 1-Phase transformer located outside. My question is, does the 800A, 120/240V switchboard (located outdoor near the trailers), has to have a main circuit breaker if we are feeding 5 trailers? The current design show 6-breakers at 150A each plus future spaces. Are we limited the 6-disconnect (breakers) if we didn't have a main breaker?

Thanks,
Disconnect limit rule set aside for a moment, what's protecting your transformer secondary conductors to the 800a Panelboard?


JAP>
 

electrofelon

Senior Member
Disconnect limit rule set aside for a moment, what's protecting your transformer secondary conductors to the 800a Panelboard?


JAP>
Actually he could use the unlimited outside tap rule for the conductors, but he needs his 408.36 PB protection as well as transformer protection.
 

faresos

Senior Member
Disconnect limit rule set aside for a moment, what's protecting your transformer secondary conductors to the 800a Panelboard?


JAP>
Nothing is protecting the 800A feeder. The 800A feeder terminate into MLO switchboard with 5 breakers. I thought this will fall under the tap rule.
 
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