Multiple Motor Feeder

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Hugh W

Member
Location
Mebane, NC
If you have one feeder supplying two motors one 10HP and 15HP @ 480V, so when determining the feeders you would multiply the largest motor by 1.25 and then add the other FLA for a total of 40.25A, since there is one conduit feed would you derate by .80 for more than three current carrying conductors in the raceway and figure the conductors for 50A?
 

Julius Right

Senior Member
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Electrical Engineer Power Station Physical Design Retired
I think OP means: two circuits, each supplying a single motor, in a same conduit. Then, according Table 310.15(B)(3)(a) for 4-6 conductors 0.8 it is the adjusting factor indeed.:roll:
 

Smart $

Esteemed Member
Location
Ohio
I think OP means: two circuits, each supplying a single motor, in a same conduit. Then, according Table 310.15(B)(3)(a) for 4-6 conductors 0.8 it is the adjusting factor indeed.:roll:
Yet if that be the case, the rest of the post makes no sense. There is no 125% largest motor factoring plus FLA of others on a single motor circuit.
 
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