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NEC code requirement

NEC code requirement

NEC code requirement

Hello everyone, does the NEC code allows that Circuit Breaker protecting Generator Equipment must have "ground fault protection" feature or LSIG, the generator is used only in the absence of normal power supply or legally required standby power. Also genarator is also use to supply fire pump just in case of fire., Thanks every one, hoping there are positive comments.

RE: NEC code requirement

The fire pump means it's complicated by a lot of circumstances that you have not gone into. The following link is not an endorsement of products, but this article does a decent job of laying out these complexities. But the first one, alluded to but not explicit, is to start with which code cycle you are required to adhere to in your state. It makes a big difference. This article refers to the 2014 Code, many places, California for example, are still on the 2011 Code.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

RE: NEC code requirement

To add the jreaf, if you have multiple generator set output breakers due to different load types (NEC Article 700, 701 and 702), 700 & 701 will have a different requirement for GF than 702. Also depends on the size of the generator and voltage.

Check out 700.6(D), 700.27, 701.6(D), 701.26 and for 702 type loads, use 215.10

RE: NEC code requirement

Per the NEC 695.4(B)(22)(a) & (b), a Fire Pump motor circuit only needs short circuit protection. Not ground fault protection, not even normal overload protection:
"(a) Individual Sources. The overcurrent protective device(s) 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 when connected
to this power supply.

(b) On-Site Standby Generators. Overcurrent protective
devices between an on-site standby generator and a fire
pump controller shall be selected and sized to allow for
instantaneous pickup of the full pump room load, but shall
not be larger than the value selected to comply with 430.62
to provide short-circuit protection only."

RE: NEC code requirement

NEC 230.95 Exception 2: The Ground fault protection provisions of this section SHALL NOT APPLY TO FIRE PUMPS

The use of the word 'SHALL' in NEC is mandatory

Note that NEC articles regarding services pertaining stand-by/back-up generators should be reviewed and discussed with the AHJ and/or registered PE prior to design/installation.

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