Dweling unit feeder size

[Designer]

I am working on a multifamily building and i have sized the service using the optional calculation and the load for the bigger unit is 124.6 Amp and i used this to size my unit feeders.

a county reveiwer made a comment that even if i use the optional calculation i need to size my feeders "According to NEC 215.2, the dwelling unit feeders must have a capacity for 125% of the calculated load"

I dont agree with him but i like to hear to point.

thanks,

 

[Dennis Alwon]

If the load were a continuous load then the reviewer would be correct. Since the calculated load on a residence is not a continuous load then there is no reason for the feeder to be size at 125%. You can actually load it 100% if the load is not continuous. If the calculated load on a home is 124.6 I would bet that the home would rarely see anything near 100 amps and if it did it would be for short periods.

 

[david luchini]

215.2 doesn't require a feeder to have a capacity for 125% of the calculated load.

It requires a feeder to have a capacity for 100% of the non-continuous load PLUS 125% of the continuous load.

IMO, the dwelling load is all non-continuous.

Edit: Or in other words, I agree with what Dennis said. :happyyes:

 

[Designer]

Thank you all