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Mixing overcurrent devices

Mixing overcurrent devices

Mixing overcurrent devices

(OP)
When selecting motor feeder circuit short circuit and ground fault protection, the code states:

You must provide the feeder with a protective device with a rating or setting not greater than the largest rating or setting of the branch-circuit short-circuit and ground-fault protective device (plus the sum of the full-load currents of the other motors of the group)

So if I use dual element time delay fuses for the branch circuits, but an inverse time breaker for the feeder, do I still use largest fuse rating for the calculation, or do I need to size the breaker as if the branch circuits were protected by inverse time breakers as well?

RE: Mixing overcurrent devices

No, you recalculate the branch circuit protection as breakers and use that information to size the feeder protection.  
430.62(A)says: "...based on the maximum permitted value for the specific type of a protective device in accordance with 430.52..."

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