225.30(c)

[m sleem]

If used 3 # of 3000a busway in parallel at 5000a disconnecting mean's busbar, would these 3 feeders meet this exception 225.30(c)??

 

[don_resqcapt19]

If used 3 # of 3000a busway in parallel at 5000a disconnecting mean's busbar, would these 3 feeders meet this exception 225.30(c)??

No need to even look at the exceptions. Conductors connected in parallel are a single circuit.

 

[m sleem]

I'm using 3#3000a busway at 5000a busbars because of voltage drop only.

 

[m sleem]

No need to even look at the exceptions. Conductors connected in parallel are a single circuit.

May be i've a problem with the definition of circuit, i believe the circuit means one breaker & one/many (load)s, but in my case three breakers & one/many (load)s.

 

[GoldDigger]

May be i've a problem with the definition of circuit, i believe the circuit means one breaker & one/many (load)s, but in my case three breakers & one/many (load)s.

Putting breakers in parallel will not always give you the obvious total ampacity of the sum of the individual breakers. Same with fuses. If total current is near overload, one breaker that is at the low side of the tolerance band will go first and the load will then take the rest out too. Similarly if one breaker is wired with higher contact or lead resistance.

 

[don_resqcapt19]

May be i've a problem with the definition of circuit, i believe the circuit means one breaker & one/many (load)s, but in my case three breakers & one/many (load)s.

I understood you to say that the bus duct was connected in parallel, that would mean there would be only one breaker or disconnect at the load end.

 

[squaredan]

Putting breakers in parallel.

Why would someone do that for a circuit, Im not understanding..

 

[m sleem]

Putting breakers in parallel will not always give you the obvious total ampacity of the sum of the individual breakers. Same with fuses. If total current is near overload, one breaker that is at the low side of the tolerance band will go first and the load will then take the rest out too. Similarly if one breaker is wired with higher contact or lead resistance.

It seems I was wrong, the coordination between the circuit breakers can be very difficult. But, my concern was how to perform maintenance on any of the separate busways where the busways running almost for 300 meters.

 

[m sleem]

It seems I was wrong, the coordination between the circuit breakers can be very difficult. But, my concern was how to perform maintenance on any of the separate busways where the busways running almost for 300 meters.

Would you think 4# vertical sections for this connection is ok, 1# for 5000a breaker & 3# for busways?

 

[m sleem]

Would you think 4# vertical sections for this connection is ok, 1# for 5000a breaker & 3# for busways?