Is Arc Energy Reduction Required for SE Rated Fire Pump Controller?

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greenville200

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We have a project with a 100HP fire pump 208V/120V 3PH. The fire pump controller is service entrance rated and has a separate disconnects for the utility feed and generator feed. The engineer has shown a 2000 amp switch board for the fire pump service, fed with 750MCM AL from the utility transformer. The switch board has arc energy reduction built in. The switchboard is in the electrical room. Then from the switchboard they show 2 sets of 250MCM AL feeding the utility power to the fire pump controller. My question is couldn't we just run the secondary from the utility transformer to a 400 amp Ct Cabinet in the electrical room and then from their go underground to the fire pump room into the fire pump controller? The fire pump controller specifications show no built in arc energy reduction. Or perhaps having the switchboard was put in by the engineer in order to provide a safer way to service the fire pump controller, but is not required by NFPA 20 or NEC 2020?

Any input on this would be appreciated.
 
I would think that arc energy reduction would be counter intuitive to anything having to do with a Fire Pump system. Generally, these systems LOWER the instantaneous trip point of the circuit protective device to reduce the arc flash energy level when someone is working in or around the equipment. That would mean IF there was an incident, the arc energy reduction feature could trip the breaker and render the fire pump inoperable, exactly when you need it! That's no bueno...

But is this spelled out somewhere in the Code? I'm not sure.
 
Checking into this further, the gear manufacturer has stated the arc energy reduction is turned on manually and then has to be turned off manually. So I would think the only concern would be if electrician or fire protection personnel were to inadvertently leave the arc energy reduction turned on. It would be good to know if there is any code that exempts fire pump controllers and fire pumps from needing arc energy reduction when the breaker is 1200 amps or more as required per NEC 2020 240.67 & 240.87.
 
Are there other loads from the 2000 amp switchboard? I see no exception for fire pumps in 240 when the OCPD is 1200 amp or higher
Yes you could run from the secondary of the XFMR to a CT cabinet and then to the fire pump controller. This is the simplest method.
I would also recommend you get a copy of NFPA 20 it goes hand in hand with Art 695. Find our from your AHJ what edition of NFPA 20 they have adopted.
As far as having arc energy protection for maintenance on the FP controller, there is not much maintenance to do in the controller. Maybe meg the motor once a year.
Fire pumps are a different beast, I had a 100 hp I did the design for, I much prefer gravity.
 
There are no other loads on the 2000 amp switchboard. The feeders go straight from the switchboard to fire pump controller and then to the fire pump. The jockey pump is even fed off of a completely different service, it is not on the 2000 amp switchboard either.
 
The conventional and simple way would be to go from the CT cabinet to the fire pump controller. There is no need for the 1200 amp gear with arc energy reduction.
On the fire pump and fire systems I have done, the electrical AHJ looks for code compliance, and the fire marshall is the one who really looks over the install, start the pump 10 times, do a flow test, ect. Would the fire marshal be concerned with the 1200 amp gear? He would probably look at the EE stamp and say OK. However I do like what Jraef said.
And lastly please remember the fire pump is sacrificial in a fire, its designed to run and burn up (no motor overloads and a big knob for emergency start).
 
Why on earth are you (or rather the engineer) using a 2000 amp board for a 100 HP pump? FLA at 208 3-phase is about 300 amps. Locked rotor current doesn't come into it except for sizing the disconnect, which technically you don't need. The fire pump controller can do that job.
 
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