480V, 3PH, 2HP motor feeder

P

pete25

Member
I have a motor that is rated for 2HP, 480V, 3PH. The feeder originates from a 20A circuit breaker at a panel and terminates to a 30A fused disconnect with 15A fuses. Is the upstream 20A breaker in violation of NEC 430.62 as it is sized greater than the maximum allowed 250% inverse time breaker in table 430.52?
 
pete25 said:
I have a motor that is rated for 2HP, 480V, 3PH. The feeder originates from a 20A circuit breaker at a panel and terminates to a 30A fused disconnect with 15A fuses. Is the upstream 20A breaker in violation of NEC 430.62 as it is sized greater than the maximum allowed 250% inverse time breaker in table 430.52?
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The 15 Amp fuses are the branch circuit protection for the motor. The feeder protection does not matter in this case.

IMO, if the feeder coming from the CB to the disconnect meets the tap rules it can be #14. Otherwise it would need to be #12. However, you might check the rules for sizing motor feeders to make sure I remembered this correctly.
 
Both the fuse and breaker are oversized for the motor SCGF Protection.
If the correct fuses were installed in the disconnect (6 amp), the breaker might be allowed dependent on the conductor size.
 
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