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Question asked by apurvadave on Apr 30, 2020
Latest reply on May 17, 2020 by rcramereleceng

I am not sure this goes to fire protection system.  I have dedicated utility service that feed service rated fire pump controller to fire pump.  I need to know the circuit breaker internal in the fire pump controller trip rating so I can size equipment grounding conductor between the controller and fire pump NEC 2014 section 250.122(A). NFPA 2013 section 10.4.3 says that manufacturer have circuit breaker as mentioned with instantaneous trip.  However,  I am confused their is also NFPA 20 10.4.4 which require locked rotor overcurrent protection as well in addition to breaker internal to fire pump controller.



I exactly don’t understand so manufacturer would have to set 10.4.3 and 10.4.4 as well?  My service rated fire pump controller internal has circuit breaker with shunt trip and they say size of breaker is 250A for 100 HP 480V three phase fire pump.  Is that not small?  I think trip setting could be higher.


Appreciate if anyone can help above questions