Fire Pump breaker in the same cubicle with another life safety breaker

[RSL]

Is it acceptable to have a fire pump breaker located in the same isolated emergency distribuition switcboard section with another life safety breaker, since they are both serving life safety equipment.

The switchboard is being served by an emergency generator.

 

[RB1]

RSL,

That is a tricky question. Although the Informational Note following 700.2 includes fire pumps as "potentially" an emergency load, the actual classification of emergency loads is deferred to other codes and standards by the NEC. For high-rises, the International Building Code classifies fire pumps, elevators, and ventilation systems as standby loads. This could be a problem for your proposed installation as far as 700.10(B)(5) is concerned. You need to check with the Building Official and maybe the Fire Official on this one.

 

[gadfly56]

Is it acceptable to have a fire pump breaker located in the same isolated emergency distribuition switcboard section with another life safety breaker, since they are both serving life safety equipment.

The switchboard is being served by an emergency generator.

The short answer is "no", somewhere in 695 it tells you to isolate the fire pump disconnecting means from all other disconnecting means and label it so there's no confusion. And if you're using a breaker instead of an unfused disconnect, it's rated for the locked rotor current, right? Modern fire pump controllers usually have the properly sized OCPD inside the controller cabinet.

 

[RSL]

The short answer is "no", somewhere in 695 it tells you to isolate the fire pump disconnecting means from all other disconnecting means and label it so there's no confusion. And if you're using a breaker instead of an unfused disconnect, it's rated for the locked rotor current, right? Modern fire pump controllers usually have the properly sized OCPD inside the controller cabinet.

Gadfly/RB1,


Thanks for all the comments.


Gadfy- I believe that you are referring to section 695-4 3 (a) normal power source.

I agree with RB1 comment "For high-rises, the International Building Code classifies fire pumps, elevators, and ventilation systems as standby loads". This should be verified with AHJ and local fire marshall.

According to 695-4 3b. Disconnecting means for an on site standby generator used as an alternate power source shall be installled in accordance with 700.10(B)(5) for emergency circuits, indicating for wiring of two or more emergency circuits supplied from the same shall be permitted in the same cabinet.

Fire pump feeders can not be installed in the same vertical switchboard section with conductors supplying loads that are designated or classed as legally required standby. To help minimize inavert opening of the fire pump circuit, the disconnecting means is required to be capable of being locked in the the closed position.

Can't see where in the code it indicates for the fire pump alternate source generator breaker must be isolated from other emergency circuits. Appreciate if you can direct me to this section of the code.

Breaker sizing for a generator breaker as altenate source should per NEC 430, Max 250% and is not required to carry the lock rotor current indefinently.

Appreciate more comments on this subject.

 

[Gregg Harris]

Gadfly/RB1,


Thanks for all the comments.


Gadfy- I believe that you are referring to section 695-4 3 (a) normal power source.

I agree with RB1 comment "For high-rises, the International Building Code classifies fire pumps, elevators, and ventilation systems as standby loads". This should be verified with AHJ and local fire marshall.

According to 695-4 3b. Disconnecting means for an on site standby generator used as an alternate power source shall be installled in accordance with 700.10(B)(5) for emergency circuits, indicating for wiring of two or more emergency circuits supplied from the same shall be permitted in the same cabinet.

Fire pump feeders can not be installed in the same vertical switchboard section with conductors supplying loads that are designated or classed as legally required standby. To help minimize inavert opening of the fire pump circuit, the disconnecting means is required to be capable of being locked in the the closed position.

Can't see where in the code it indicates for the fire pump alternate source generator breaker must be isolated from other emergency circuits. Appreciate if you can direct me to this section of the code.

Breaker sizing for a generator breaker as altenate source should per NEC 430, Max 250% and is not required to carry the lock rotor current indefinently.

Appreciate more comments on this subject.

Are you not looking for 695.4(A) Direct Connection. The supply conductors shall directly connect the power source to either a listed fire pump controller or listed combination fire pump controller and power transformer switch.

Where the power source is supplied by on-site generator(s), the supply conductors shall connect to a generator disconnecting means dedicated for the purpose of serving the fire pump. The disconnecting means shall be located in a separate enclosure from the other generator disconnecting means.

695.4(1) Over-current Device Selection. The over-current protective device(s) shall be selected or set to carry indefinitely the sum of the locked -rotor current of the fire pump motor(s)----etc.