Feeder for VFD
Feeder for VFD
(OP)
Chapter 430, Part X of NEC requires that feeders for VFD be rated at 125% of their rated input. I would like to know if I'm interpreting this correctly. If I have a VFD rated at 400A, the feeder for this VFD will have to be sized for 500A (400*1.25)? Ahead of the VFD, the feeder for the motor will be sized for the particular motor? Can I use the Nameplate of the motor to size the feeder instead of the tables?





RE: Feeder for VFD
RE: Feeder for VFD
The distorted current on the input of the VFD is the reason for the increased cable size requirements. Th output current should not be distorted so standard ratings can apply.
Best regards,
Mark Empson
http://www.lmphotonics.com