430.24 defines sizing of feeder conductors feeding multiple motors and other loads, at 125% of largest motor plus 100% of other motors.
430.122(D) defines sizing of feeder conductors feeding multiple motors including drives, and refers back to 430.24, using nameplate input current of drive to calculate ampacity.
If I have an application where the actual demand load per drive will be less than the nameplate input current of the drive(s) - can I use 430.26 to reduce the ampacity requirement of my FEEDER conductors, as long as the individual BRANCH conductors are 1.25 x Input rating of each individual drive?
For instance, I have a feeder supplying (4) 30 HP drives each with nameplate of 47A. 430.24 would require 1.25 x 47A + sum of other currents, or 199.75A. But I know that for my application, with 4 motors running, current will be much less than that. Does 430.26 allow me to adjust demand? 430.26 references 'duty cycle, intermittently, or from all motors not operating at the same time'. In my case, all the motors are operating continuously, just at loads less than the drive input rating.
I'm referencing 2020 NEC.
430.122(D) defines sizing of feeder conductors feeding multiple motors including drives, and refers back to 430.24, using nameplate input current of drive to calculate ampacity.
If I have an application where the actual demand load per drive will be less than the nameplate input current of the drive(s) - can I use 430.26 to reduce the ampacity requirement of my FEEDER conductors, as long as the individual BRANCH conductors are 1.25 x Input rating of each individual drive?
For instance, I have a feeder supplying (4) 30 HP drives each with nameplate of 47A. 430.24 would require 1.25 x 47A + sum of other currents, or 199.75A. But I know that for my application, with 4 motors running, current will be much less than that. Does 430.26 allow me to adjust demand? 430.26 references 'duty cycle, intermittently, or from all motors not operating at the same time'. In my case, all the motors are operating continuously, just at loads less than the drive input rating.
I'm referencing 2020 NEC.