The branch circuit breaker trips intermittently for a 3 phase motor circuit. It is a 5 Hp, 208 V motor FLA 12.4 SF 1.15. I believe it is a severe duty rated motor. The branch breaker is 30 A, and the contractor has megged the wiring, changed the motor and the breaker, and the problem persists. I don't have access to NEC tables, but understand they must be used for conductor sizing and SC/GF protection. I suspect the breaker is sized too tight for in-rush, and a 35 A breaker is allowed. I'm trying to learn Art 430, so could someone verify if I'm heading in the right direction.