Sizing Conductors based on nameplate FLA for motor load

[Mustang125]

I have heard before that for AC units you can size the wire based on the FLA on the nameplate and not based on OCP, so I needed to know for myself so I started digging and watched some of mikes videos and it does indeed appear that way. (although even with his code references I still cant find where is clearly states this) but beside that, my current situation is a compressor load which id consider a motor load and was wondering if the same rules can be applied because it has a nameplate. I went to 430.6 and it seems like if the motor is over 1200rpm then you CANT size the conductors based on the FLA on the nameplate, so id have to size the conductors to the OCP, am I reading this right? I have attached the nameplate in question.

 

[infinity]

That nameplate does not have a listed MCA so you wouldn't size it like an AC unit. I would use 125% of the motor current (114 amps) plus the additional load (123-114=9 amps) listed on the nameplate.

*Please update you profile to include your occupation. Thanks.

 

[Mustang125]

That nameplate does not have a listed MCA so you wouldn't size it like an AC unit. I would use 125% of the motor current (114 amps) plus the additional load (123-114=9 amps) listed on the nameplate.

*Please update you profile to include your occupation. Thanks.

So if I'm understanding you correctly, it would be 114a * 125% = 142.5a plus 9a for a total of 151.5a = 1/0cu?

 

[david luchini]

So if I'm understanding you correctly, it would be 114a * 125% = 142.5a plus 9a for a total of 151.5a = 1/0cu?

2/0 cu

 

[Dennis Alwon]

So if I'm understanding you correctly, it would be 114a * 125% = 142.5a plus 9a for a total of 151.5a = 1/0cu?

You cannot use 90C column unless you are de-rating. The max ampacity is usually 75 based on wire insulation and termination.