MCC Feeder bucket selection

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adityalagudu

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victoria,TX,USA
What type of MCC dual CB feeder bucket is required to feed 480V, 2A, 14 LRA, 1HP motor? Also need 3 pole fuse. What is purpose of using fuse and circuit breaker at the same time?
 
Will let the others say the actual but from what little IKnow so far, the fuses are for the inrush current for starting and the breaker is for faults... I may have those backwards however...
 
MCC Feeder bucket selection

What type of MCC dual CB feeder bucket is required to feed 480V, 2A, 14 LRA, 1HP motor? Also need 3 pole fuse. What is purpose of using fuse and circuit breaker at the same time?
 
adityalagudu said:
What type of MCC dual CB feeder bucket is required to feed 480V, 2A, 14 LRA, 1HP motor? Also need 3 pole fuse. What is purpose of using fuse and circuit breaker at the same time?
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So assuming that since you are saying "feeder bucket", the motor controller is at the machine, not the MCC so you are only wanting a feeder. If that's the case, the minimum feeder conductor size is 14ga, so you would use a 15A feeder breaker in the bucket.

The only time you might need both a CB and fuses is when the fault duty rating is extremely with some types of older CBs i.e. 100kA, or on something like a VFD where the UL listing requires fuses, but you over size the fuses because you want a re-settable CB for convenience.
 
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Thank you for the information. Yes the motor controller is at the machine which is MOV. Since two MOV motors needs the power supply, we want to use dual pole breakers on the MCC. What should be the suggestible fuse rating in this case? Should the trip rating for each motor consider as 15 A only?
 
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