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#21609 - 02/06/03 08:06 AM Sizing Emergency Generator
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
I was called upon to size an emergency generator as an alternate power source for a fire pump. There are other loads as well. However, I want to focus on the fire pump load for now. I plan to use the horsepower rating of the motor to calculate load. I reviewed the 2002 NEC Handbook 695.3(B)(1)and learned the generator does not need to be sized for lock rotor of fire pump.
Where the alternative source of power is an on-site generator, the alternative source disconnecting means and the alternative source overcurrent protective device(s) for the electric-drive fire pump are not required to be sized for locked-rotor current of the fire pump motor(s). Rather, the circuit components of the alternative source are permitted to be sized according to Article 430, provided they are “selected or set to allow instantaneous pickup and running of the fire pump load.” See 445.12(A).
Did I interpret it properly?

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#21610 - 02/06/03 02:52 PM Re: Sizing Emergency Generator
electure Offline

Member

Registered: 12/24/00
Posts: 4226
Loc: Fullerton, CA USA
If your fire pump has it's rotor locked indefinitely, it's a much bigger problem.(that should have been corrected earlier)
I believe you're correct...S

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