NEC CB Size for Motor Loads

[djr3203]

NEC allows for a maximum 250% the FLA of a motor for an inverse-time CB. Is there somewhere in the NEC that allows you to use a 20A CB as the minimum CB size for protecting motors?

As an example, I have a 1-1/2HP 460V, 3PH motor with an FLC of 3A. 3A x 2.5 = 7.5A, so does the circuit breaker have to be 15A? Or can I use a 20A.

I thought I remember somewhere in the NEC that allowed for 20A CB to be the minimum CB size for commercial applications, however, I can't seem to find it now. I also realized that this was probably under Chapter 2, which would not hold true if Article 430 doesn't stipulate it?

Thanks for the help all.

DJR

 

[melspuds]

djr3203
NEC Art. 240.6(A) is the lowest standard size breaker. Therefore you need to use 15Amp breaker 3 phase 480 or 600 Volt.
I believe you are referring to 240.4(B),&(C), 240.4(G) Table 240.4(G) the catch all for everything.
Hope this helps,
Dave