(sorry) emergency egress lighting should be accounted for elsewhere. We all know there's nothing like an experienced pump rep., but that hardly satisfies our curiosity. I don't necessarily recommend it, but I never let "not my area of expertise" stop me from pondering something :)
> On Apr 5, 2014, at 3:05 PM, Brad Casterline <[email protected]> wrote: > > 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 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
