Ground Fault Exemption for Fire Pumps

[poweringtech]

In one of the provision in article 240, there is an exemption that fire pump may not have ground fault protection. Will this be more dangerous because a ground fault is a short circuit fault for a solidly grounded system. The code is not clear and this may result to further burning of the establishment if ground fault protection for fire pump will be removed.

The code should emphasized that for a fire pump to have no ground fault protection the system should be either UNGROUNDED OR HIGH IMPEDANCE GROUNDED. Or if the existing system is SOLIDLY GROUNDED then an isolation transformer should be used to convert the Solidly grounded to either ungrounded or high impedance grounded.

 

[iwire]

The code should emphasized that for a fire pump to have no ground fault protection the system should be either UNGROUNDED OR HIGH IMPEDANCE GROUNDED. Or if the existing system is SOLIDLY GROUNDED then an isolation transformer should be used to convert the Solidly grounded to either ungrounded or high impedance grounded.

It can't emphasize that as it is not a requirement.

The idea here (as I understand it) is to keep the fire pump running while the building burns around it.

As a further example of this look to 695.4(B)(1).

(1) Overcurrent Device Selection. The overcurrent protective device(s) shall be selected or set 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.

 

[haskindm]

240.13 does not apply to Ground Fault protection such as afforded by normal circuit breakers and fuses, it is referring to GFCI protection for equipment over 150-volts to ground and protected at 1000 amps or more. The Fire pump circuit would still require "short circuit and ground fault protection" as required in article 430 and 695.6(D). Article 695 seems to be confusing as it specifies that branch circuits shall be protected against short circuits only. Article 430 says that the branch circuit protection device protects against short circuit and ground faults. How does a circuit breaker determine the difference between a fault between circuit conductors (short circuit) and a "ground fault" which would be a connection between an ungrounded (hot) conductor and any grounded object (such as the metal conduit in which the conductors are installed)? GFCI protection is not required on fire pumps, but any circuit breaker or fuse will protect against Ground Faults. I think the committee needs to clarify their language. There seems to be a lack of communication betwwen the article 430 panel and the article 695 panel.