tahir mehmood
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As Per NEC- 430.62 A:
A feeder supplying a specific fixed motor load(s) and consisting of conductor sizes based on 430.24 shall be provided with a protective device having a rating or setting not greater than the largest rating or setting of the branch-circuit short-circuit and ground-fault protective device for any motor supplied by the feeder [based on the maximum permitted value for the specific type of a protective device in accordance with 430.52, or 440.22(A) for hermetic refrigerant motor-compressors], plus the sum of the full-load currents of the other motors of the group.
Where the same rating or setting of the branch-circuit short-circuit and ground-fault protective device is used on two or more of the branch circuits supplied by the feeder, one of the protective devices shall be considered the largest for the above calculations.
i have 2 pumps each 380/3phase/ volts, 19.99 hp each pump, each FLA is 35.1 amperes.
Note: the above code underlined applies to the calculation below.
Branch OCPD: NEC- 430.52 C 1
For Pump 1 = 35.1 * 2.50 = 87.75
Next standard size is 90 amperes
For Pump 2 = 35.1 * 2.50 = 87.75
Next standard size is 90 amperes
Feeder OCPD:
As per NEC-430.62 A
90 + 35.1 = 125 Amperes
So the feeder size must be 125 amperes.
Please advise my feeder calculation matches the code lines underlined.
A feeder supplying a specific fixed motor load(s) and consisting of conductor sizes based on 430.24 shall be provided with a protective device having a rating or setting not greater than the largest rating or setting of the branch-circuit short-circuit and ground-fault protective device for any motor supplied by the feeder [based on the maximum permitted value for the specific type of a protective device in accordance with 430.52, or 440.22(A) for hermetic refrigerant motor-compressors], plus the sum of the full-load currents of the other motors of the group.
Where the same rating or setting of the branch-circuit short-circuit and ground-fault protective device is used on two or more of the branch circuits supplied by the feeder, one of the protective devices shall be considered the largest for the above calculations.
i have 2 pumps each 380/3phase/ volts, 19.99 hp each pump, each FLA is 35.1 amperes.
Note: the above code underlined applies to the calculation below.
Branch OCPD: NEC- 430.52 C 1
For Pump 1 = 35.1 * 2.50 = 87.75
Next standard size is 90 amperes
For Pump 2 = 35.1 * 2.50 = 87.75
Next standard size is 90 amperes
Feeder OCPD:
As per NEC-430.62 A
90 + 35.1 = 125 Amperes
So the feeder size must be 125 amperes.
Please advise my feeder calculation matches the code lines underlined.
