how should I calculate generator feeders? I have a 17 KW generator 71 amps, 310.15 allows #4 for 100 amps, but does it allow #6 for 71 amps? Do I size according to 310.16 which is still #4? Thanks, H20
You can only use 310.15(B)(6) if this is a main feeder for the entire dwelling, basically an extension of the service entrance from a disconnect. That is, by definition, a #4 minimum. In no case could you interpolate down to a #6. Any other application has to use 310.16.