I have an inspector tell me my wiring is incorrect. Wiring a chiller, 480v 3 phase. The nameplate says FLA=96 amps. MOCP= 225 amps.
Since it is 1 compressor i add 25% to the entire 96 amps = 120 amps. At 75c i use [3] #1 copper THHN [130 amps]. Then since i am using a 400 amp source i full size tap [split]to 2 fused disconnects. [Their are 2 chillers.] So now i have 2- 200 amp disconnects each with 200 amp fuses. Now i am told the wire is to small for the fuse size. So can someone explain help me in detail including article numbers how this is correct. I know it is, i just can't explain it very well including how it is ok for overloads [built in] to protect the motor. Since the MOCP is 225 amps the factory must have concluded that over current protection can be raised from 175% to 225%. The chiller is UL listed. The wire feeding the disconnects is not in question, the question is the #1 wire from the disconnects to the chillers since the disconnects have 200 amp uses.
Since it is 1 compressor i add 25% to the entire 96 amps = 120 amps. At 75c i use [3] #1 copper THHN [130 amps]. Then since i am using a 400 amp source i full size tap [split]to 2 fused disconnects. [Their are 2 chillers.] So now i have 2- 200 amp disconnects each with 200 amp fuses. Now i am told the wire is to small for the fuse size. So can someone explain help me in detail including article numbers how this is correct. I know it is, i just can't explain it very well including how it is ok for overloads [built in] to protect the motor. Since the MOCP is 225 amps the factory must have concluded that over current protection can be raised from 175% to 225%. The chiller is UL listed. The wire feeding the disconnects is not in question, the question is the #1 wire from the disconnects to the chillers since the disconnects have 200 amp uses.