Wirenut21880
Member
- Location
- Yakima, Washington
- Occupation
- Electrician
I have a 250 HP 480V motor that I need to run a feeder to. Nameplate on the motor is 285, but NEC FLA is 302A. I am paralleling in a 3" rigid. Here's how I calc'd up my feeder size: 302A X 1.25% = 377.5A. 377.5/2= 188.75 minimum amps per paralleled run. 4/0 THHN in the 90degree column is good for 260A, but since I have 6 current carrying conductors in my conduit I have to take 260/.8 which equals 208A.
If I used nameplate of 285 I could get away with 3/0, but I'm pretty sure I have to go off of NEC FLA. Am I looking at this correctly?
If I used nameplate of 285 I could get away with 3/0, but I'm pretty sure I have to go off of NEC FLA. Am I looking at this correctly?
