Breaker used for motor protection upstream of contactor

[mull982]

Lets say we have a starter that consists of a contactor and an overload devcice. Typically with this starter we have a breaker either an instantaneous or inverse type at the starter but lets say this breaker is 100ft upstream of the actual starter. Could this breaker be considered a branch circuit breaker for this motor starter? Since it would not be listed as a combination breaker I'm guessing it would have to be an inverse type applying to the rules of 430 and not have it larger than 250% of motor rating.

Can a motor branch circuit breaker be located upstream of the contactor as mentioned adhering to the rules of motor branch circuit protection.

If this is not allowed, then I'm guessing a motor branch circuit breaker needs to be added at the starter location, and this upstream breaker is now a feeder breaker which must be rated at 125% of motor FLA?

 

[Cold Fusion]

If this is not allowed, then I'm guessing a motor branch circuit breaker needs to be added at the starter location, and this upstream breaker is now a feeder breaker which must be rated at 125% of motor FLA?

You need a disconnect at the controller. Doesn't have to be a circuit breaker.

Having said that, I don't think I have ever put in a starter with the cb 100 feet away.

And if you want to use two cbs, just call the first one the motor circuit breaker, sized at 250% and the one next to the controller as the controller/motor disconnect - size however big you want. Itis just a switch.

cf

 

[mull982]

You need a disconnect at the controller. Doesn't have to be a circuit breaker.

Having said that, I don't think I have ever put in a starter with the cb 100 feet away.

And if you want to use two cbs, just call the first one the motor circuit breaker, sized at 250% and the one next to the controller as the controller/motor disconnect - size however big you want. Itis just a switch.

cf

O.K. So if we do add a disconnect or CB at controller can the upstream breaker be 250% even if this is larger than cable size? In other words is this breaker still just providing short circuit protection while the motor overload provides overload protection for this cable and the cable between the controller and the motor as long as both cables are 125% of motor fla?

 

[don_resqcapt19]

This is really a feeder under the definitions in the code and 430.63(A) applies. With a single motor, the rules don't really change and you are good to go with conductors that have an ampacity of 125% or more of the motor FLA and an inverse time breaker rated at 250% of the motor FLA.