Industrial Machine Feeder Sizing

[User2]

We acquired a new machine today with the following nameplate information:

68KVA
AC 460, 3Phase, 60Hz
*This unit comes equipted with a 100A breaker*

Based off the kva rating it comes out to 81.79A @480V. 81.79 x 0.125 = 10.22. 81.79 + 10.22 = 92A. This looks like this unit is already sized for 125percent of the KVA and they upsized the breaker to the next size available @ 100A. Does the feeders for this unit need an additional 125percent upsizing on top of the breaker at 100amps or is it more than practical to to use the breaker 100A value for wire sizing?

 

[Jljohnson]

your math is a little off as you used.125 as your multiplier instead of .25, .125 is only 12-1/2% when you need 25%. 81.79 x 1.25= 102.24. Size the feeder to that value.

 

[bob]

Does the nameplate give you a minimum size conductor and a max size breaker?