Originally Posted by
Rollie Meyers
A plug/receptacle used for a disconnect is required to be rated for the HP of the equipment, for motors above 3 HP, they are super expensive making a safety switch pretty economical in comparison, pretty much of all the cord & plug connected single phase 5 HP equipment does not meet code. 430.109(F)
NEC wrt motors is an entirely different animal. You must account for ground fault protection, short circuit protection, and over-current protection. All at the same time.
.... AND make sure that the over-current protection allows the motor to start .... at maybe six times its running amps.
Each part has its own table to determine conductor size and circuit breaker or fuse size, and sometimes it can lead to weird pairings... a 14g wire on a 30 amp breaker, for instance.
Comments made here are my own and, according to my children, do not reflect the opinions of any other person... anywhere, anytime.