Small 1-room building. The system has a 1/4HP exhaust fan at one end of a building and a motorized damper at the other end. It will be controlled by a wall switch. Breaker is thermal magnetic and voltage is 120V. The panel is in the same room and thermal switches will be called for at each device. The question is on the branch circuit.
Please confirm for me if I am correct, if the exhaust fan were the only load, per 430.52, the breaker would have to be 15A and could not be 20A correct? (5.8 FLC x 2.5 = 14.5A, next size up = 15A).
The motorized damper is not known at this time, but after doing some checking, an example would be 0.26A.
Per 430.53(A), it appears that a 20A breaker would be acceptable.
Or, is this a feeder until the thermal switch is reached in which case,430.62(A) would apply: (5.8A x 2.5 = 14.5A = 15A OCPD + 0.26A = 15.26A = next size down = 15A breaker)?
Motor circuits get confusing especally looking at figure 430.1. Typcally, if you have just 1 motor, there is no "feeder" you have the branch circuit short circuit ground fault protection (breaker) then a non-fused disconnect at the motor. I guess if the disconnect at the motor were fused, then the breaker would be the motor feeder short circuit ground fault protection and the fused disconnect would be the branch-circuit protection?
Please confirm for me if I am correct, if the exhaust fan were the only load, per 430.52, the breaker would have to be 15A and could not be 20A correct? (5.8 FLC x 2.5 = 14.5A, next size up = 15A).
The motorized damper is not known at this time, but after doing some checking, an example would be 0.26A.
Per 430.53(A), it appears that a 20A breaker would be acceptable.
Or, is this a feeder until the thermal switch is reached in which case,430.62(A) would apply: (5.8A x 2.5 = 14.5A = 15A OCPD + 0.26A = 15.26A = next size down = 15A breaker)?
Motor circuits get confusing especally looking at figure 430.1. Typcally, if you have just 1 motor, there is no "feeder" you have the branch circuit short circuit ground fault protection (breaker) then a non-fused disconnect at the motor. I guess if the disconnect at the motor were fused, then the breaker would be the motor feeder short circuit ground fault protection and the fused disconnect would be the branch-circuit protection?
