Good afternoon.
We added a generator to a house in which we showed (2) sets of 3/0 in two separate 2" conduits fed from a 400A CB on the generator. The electrician installed all these in (1) 3" pipe rather then (2) 2" but he forgot to de-rate them accordingly (80 % for 6 conductors) so the inspector is giving him a problem. The load is approximately 317 amps so 317A * 0.8 = 254 amps which would mean we would need a 300A CB but this would be less then the calculated load. Does anyone have any suggestions here? Anything I am missing?
We usually dont put more then three current carrying conductors in a conduit on the design side so I dont have to derate too often. Maybe there is a hidden rule I am missing here?
We added a generator to a house in which we showed (2) sets of 3/0 in two separate 2" conduits fed from a 400A CB on the generator. The electrician installed all these in (1) 3" pipe rather then (2) 2" but he forgot to de-rate them accordingly (80 % for 6 conductors) so the inspector is giving him a problem. The load is approximately 317 amps so 317A * 0.8 = 254 amps which would mean we would need a 300A CB but this would be less then the calculated load. Does anyone have any suggestions here? Anything I am missing?
We usually dont put more then three current carrying conductors in a conduit on the design side so I dont have to derate too often. Maybe there is a hidden rule I am missing here?
