deputygrsmith
Member
I have a question asking if 20a OCPD can protect 480v, 3 phase, (6)1/2hp motors, (3) 3/4hp motors & (2) 1hp motors.
The book and I both come up with a total of FLA of 15.6a
The 20a OCPD would be 16a (80%), so logically it could protect the 11 motors.
I don't work with motors much, but I thought that 20a OCPD can only be used on 120v circuits? Wouldn't a 15a OCPD be required per 430.53a because of the 480v circuit and it would not be able to supply 11 motors?
Can you help me clarifty this, because the book says you can protect the above motors with a 20a OCPD.
The book and I both come up with a total of FLA of 15.6a
The 20a OCPD would be 16a (80%), so logically it could protect the 11 motors.
I don't work with motors much, but I thought that 20a OCPD can only be used on 120v circuits? Wouldn't a 15a OCPD be required per 430.53a because of the 480v circuit and it would not be able to supply 11 motors?
Can you help me clarifty this, because the book says you can protect the above motors with a 20a OCPD.
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