I am making the assumption that the first circuit breaker is sized for the motor circuit and is for short circuit and ground fault protection. Further, I assume the downstream fuses are dual-element time-delay and are set close to provide backup protection for the motor. The motor overloads will protect the motor in most cases. Fuses sized close will provide loss of phase protection for the motor.

In other words, if all the rules of Article 430 are followed, it will work well. Without having all the specifics, we can't give you any more than that. [Linked Image]

Charlie Eldridge, Indianapolis Utility Power Guy