Load current or circuit brealer rating

[mego6000]

Hi all

Could any one help me about feeder sizing, I don?t know which exactly shall be used
"The load current" or "Protective device rating" also is it the rating of the CB or its setting that shall be used?

For example if the load is 75A and the CB is adjustable 100/80A, then when sizing its cable which current shall I use the 75A of the load or the 100A (the rating of CB) or the 80A (the setting of CB).

Thanks

Amged

 

[Pierre C Belarge]

Take a look at 240.4.

 

[mego6000]

thanks alot