NEC Article 430.53 question
NEC Article 430.53 question
(OP)
I am confused with article 430.53(C)(4) and (C)(5), I want to size a branch circuit short circuit ground fault protection device for a three motor installation. Two motors are 5hp and the third is 3hp on a 480Vac 3ph system. Tables say 5hp is 7.6amps and the 3hp is 4.8 amps
So do I multiply 7.6x250%+7.6+4.8 to get the breaker, or do i have to size the breaker for the smallest motors overload relay according to 430.53(C)(5). Any help or hints would be welcome thank you.
So do I multiply 7.6x250%+7.6+4.8 to get the breaker, or do i have to size the breaker for the smallest motors overload relay according to 430.53(C)(5). Any help or hints would be welcome thank you.





RE: NEC Article 430.53 question
RE: NEC Article 430.53 question
If you are doing this in the field with components that do not have specific manufacturer's instructions as to SCPD ratings, you would follow B and D.