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Sizing Molded Case Circuit breaker for this service

Sizing Molded Case Circuit breaker for this service

Sizing Molded Case Circuit breaker for this service

(OP)
Guys,
I have 3 motors (200 hp, 2 hp, 5 hp) in a service and I want to size the main circuit breaker for this service.
Articles 430.31-44 of NFPA talk about overload protection and 430.51-58 talk about short circuit protection.
If I want to size a Molded Case Circuit breaker for this service, which article applies?

RE: Sizing Molded Case Circuit breaker for this service

Once you have more than one device, you jump to 430.53 and up, for multiple motors on one branch circuit.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

RE: Sizing Molded Case Circuit breaker for this service

(OP)
I know for main breaker feeding a service, I need to use thermal-magnetic MCCB. Now, when we say NEC amp for this service is 310 A and the next higher breaker size (350 A) should be selected, what does this 350 A exactly mean? Is it thermal section of the breaker?

RE: Sizing Molded Case Circuit breaker for this service

Yes.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

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