Minimum motor wire size

[james_mcquade]

Hi everyone.

I have a customer that wants to use #18 wire to power a 3/4 hp motor.
208 volts, 3 phase, neutral & ground. 10 amp breaker feeding a VFD powering the motor

I have always used #14 as the minimum.
Before i submit my report, i wanted to cite the code for the #14 wire size, but cannot locate it.

What is the minimum wire size allowed for powering a 3 phase motor?
Please cite the code, if i'm wrong, i would definitely like to know.
Since i cannot cite a code, all i can do at this point is make a recommendation.

Thanks in advance,
James

 

[augie47]

Look at the conditions in 240.4(D)(1) and see if the installation complies.

 

[david luchini]

I think you are looking for 310.5.

 

[Dennis Alwon]

James don't let the customer dictate what you do. The only time I have seen wires that small were for the split system sanyo units with DC motors.

 

[james_mcquade]

Thanks for the replies.
Dennis,
I have a good relationship with this customer and he trusts me and my opinion.
I wanted to give him the code reference because one of the contractors on the bid list
has been, well lets say, been known to bend the rules and caused a lot of grief in the
past. They are having a hard time getting him off the bid list.

regards,
james.