Fire Pump Controller

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augie47

augie47

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State Electrical Inspector (Retired)
Inspected a 20HP 208v 3 phase fire pump install
All aspects appear to meet NEC other than the LISTED controller has a main breaker marked "100 amps"
The motor has a LRA of 314 amps.
This would appear to be a problem but the controller is listed for the 20HP fire pump.
Is it possible on a Fire Pump Controller that the "100 amp" breaker is designed to handle the LRA ??
 
augie47 said:
Inspected a 20HP 208v 3 phase fire pump install
All aspects appear to meet NEC other than the LISTED controller has a main breaker marked "100 amps"
The motor has a LRA of 314 amps.
This would appear to be a problem but the controller is listed for the 20HP fire pump.
Is it possible on a Fire Pump Controller that the "100 amp" breaker is designed to handle the LRA ??
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Yes, don't worry about the breaker internal to the controller. One of the pump manufacturers has a standard sheet they fax (or e-mail, I suppose now) to AHJ's who don't understand the difference between internal components of a listed fire pump controller and the external disconnect that has to carry the LRC.
 
augie47 said:
Inspected a 20HP 208v 3 phase fire pump install
All aspects appear to meet NEC other than the LISTED controller has a main breaker marked "100 amps"
The motor has a LRA of 314 amps.
This would appear to be a problem but the controller is listed for the 20HP fire pump.
Is it possible on a Fire Pump Controller that the "100 amp" breaker is designed to handle the LRA ??
Click to expand...

I had encountered similar situation only when reviewing at my desk drawing my friend. I request internal breaker size fire pump controller to size downstream EGC. Turned out that what was written on plans was breaker frame size Not the breaker trip.

So the breaker trip setting was like 20x FLA but frame size was much lower. All this is in NFPA 20 fire pump. Breaker frame size how to is in that standard i think 1.25xFLA but not sure

So it could be 100A is just breaker frame size Not what it trips.
 
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Sometimes fire pump controllers have 2 breakers in series. NEC only applies to line and load wiring, not internal controller wiring.
 
tom baker said:
Sometimes fire pump controllers have 2 breakers in series. NEC only applies to line and load wiring, not internal controller wiring.
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agreed.. but as an inspector I hate somewhat to walk away from something as important as a fire pump when the contractor questions a component. "not my job" just doesn't feel right :)
 
augie47 said:
agreed.. but as an inspector I hate somewhat to walk away from something as important as a fire pump when the contractor questions a component. "not my job" just doesn't feel right :)
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Call the manufacturer of the controller and ask for their tech support group. They've probably gone through this hundreds of times. They should be able to put you at ease.
 
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