Minimum conductor size for motors

[mull982]

Trying to find if there is a minimum size conductor that can be used for motors. I had thought it was #12 but can't find anything in the NEC.

From what I can see #14 would be o.k. to use for motors. Is there something in the NEC i'm missing?

 

[augie47]

310.5 would seem to indicate a #14 for motor power circuits. My OPINION
is that 430.72 along with 724.43 will allow you to use as small as a #18 if all conditions are met.

 

[don_resqcapt19]

310.5 would seem to indicate a #14 for motor power circuits. My OPINION
is that 430.72 along with 724.43 will allow you to use as small as a #18 if all conditions are met.

Gus, 430.72 only applies to motor control circuits and not to the motor branch circuit conductors.
However it is my opinion that the reason 240.4(D)(1) & (2) were added to the code was to permit the use of smaller conductors for applications like this. That being said, 310.5 stands in the way of using the smaller conductors at this time. It looks like that section was not coordinated with the change in 240.4(D).

 

[augie47]

Thank you Don. The "control wires" fact was in my mind but failed to make it to my typing hand.View attachment 3550
The reason for my comment "opinion" was the clash between 310.5 and 240.4. Thanks for the clarification.

 

[bffttsiu]

310.5 includes the phase "...except as permitted elsewhere in this Code.". 240.4(D)(1) and (2) is noted as permitting sizes 18 and 16 AWG provided all conditions are met. (Shown in 2008 NEC Handbook)