Conductor ampacity for overhead crane circuit.

[steve61]

I have an overhead crane that I need to run a 460 volt 3 phase circuit to. After doing the amperage calculations and coming up with 46.375 amps ( # 8 thhn in the 75 degree column) I got an actual picture of the crane nameplate showing a required circuit ampacity of 115 amps. With the value of 115 amps, do I need to multiply 115 by 1.25 getting 143.75 amps needing # 1/0 wire or go just with the name plate rating of 115 amps and # 2 wire ? (all amperages from the 75 degree column).

 

[don_resqcapt19]

crane nameplate showing a required circuit ampacity of 115 amps. With the value of 115 amps, do I need to multiply 115 by 1.25 getting 143.75 amps

I think you need to know how the nameplate required ampacity was calculated. The 125% may already be included like it is for the AC minimum circuit ampacity.

 

[augie47]

Cranes follow a different set of rules. See Art 610

 

[Elect117]

See 610.14. I don't think it is that simple.

The nameplate rating at 100% but the wire size might require you to have the duty rating.

Is this just the feeder circuit to a industrial control panel (409.20) or is this to the crane itself?

 

[steve61]

This is just the circuit to the crane itself. Name plate on the main control panel for the crane system.

 

[augie47]

I haven't dealt with Art 610 to be anywhere close to proficient but it certainly appears a #2would more than adequate.