I would think you could subtract the requirements for light and heat, in an emergency, from what the fire pump motor needs. Emerg
> On Apr 5, 2014, at 12:11 PM, "Don Lowry" <[email protected]> wrote: > > References from NFPA-20 (2010 edition) > > Situation: > > Fire Pump to be installed on ESFR system (75 hp) electric motor. > 9.2.2 (1) or (5) > > On down through Chapter 9 to; > > 9.2.3.4 Where the overcurrent protection permitted by 9.2.3 > is installed, the overcurrent protection device shall be rated to > carry indefinitely the sum of the locked rotor current of the > fire pump motor(s) and the pressure maintenance pump motor( > s) and the full-load current of the associated fire pump > accessory equipment. > > OK, so the locked rotor current is 543 amps, plus jockey pump, lights, heat, > etc added would require a 600 amp over current protective device. This is > what the Engineer and I determined would be the requirement for this > dedicated service to the fire pump. > > When the engineer submitted his electrical service plan (600 amp service) to > the city, the City Plan Reviewer states that we don't need a 600 amp > service, but rather a 125 amp service. > > In reading through Article 695.4 of the NEC. It states: > "Where the locked rotor current value does not correspond to a standard > overcurrent device size, the next standard overcurrent device size shall be > used in accordance with 240.6. The requirement to carry the locked rotor > currents indefinitely shall not apply to conductors or devices other than > overcurrent devices in the fire pump motor circuits." > > So, does this mean that the service itself (transformer) and related > conductors can be per normal size (125 amp) with just a 600 amp fuse in the > disconnect before the controller? > > In 30 + years this is the first time I have ever been asked about this. > Before I was only asked about pump size etc , and when installed and checked > at pump start-up there was indeed a fuse of appropriate size in the service > disconnect. So I assumed all was correct. I'm just wanting to make sure > the Engineer and I understand the requirements for the actual electrical > service provided. I know it's not my area of expertise, nor my > responsibility, just curious. > > Thanks in advance for any help. > > Don Lowry, CET, RME (TX) > > > > > > > > > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
