Fire Pump wiring

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faresos

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Hello every one...

We are in the process of designing a data center, this project has two separate normal power sources, A & B (13.8KV) and the whole building is backed up by 4 generators (13.8KV), N+1 configuration. There are two fire pumps (one is redundant), the thought is to provide two transformers (13.8KV pri- 480V Sec) for each fire pump. One transformer will powered from the normal 13.8KV switchgear (source A) and the other transformer will be powered from the generator MV paralleling switchgear. At the secondary of the transformers, each will have two feeders; each will feed each of the fire pump via ATS/Controller. My question, does this meet the requirement of the NEC section 695? Do I have to tap a head of the main normal service disconnect (at the transfromer) for this installation in lieu powering it from a feeder breaker? Anythoughts....

Thanks,
 
faresos said:
Hello every one...

We are in the process of designing a data center, this project has two separate normal power sources, A & B (13.8KV) and the whole building is backed up by 4 generators (13.8KV), N+1 configuration. There are two fire pumps (one is redundant), the thought is to provide two transformers (13.8KV pri- 480V Sec) for each fire pump. One transformer will powered from the normal 13.8KV switchgear (source A) and the other transformer will be powered from the generator MV paralleling switchgear. At the secondary of the transformers, each will have two feeders; each will feed each of the fire pump via ATS/Controller. My question, does this meet the requirement of the NEC section 695? Do I have to tap a head of the main normal service disconnect (at the transfromer) for this installation in lieu powering it from a feeder breaker? Anythoughts....

Thanks,
Click to expand...

Pretty sure your installation would comply, but expensive. Why not just power it from 2 different sources? Normal and a board supplied by generator?
Reference 695.3.B.1
 
Thats what I have in the current design; each pump is powered from two sources, normal and from the generator but my main concern was if I really have to tap a head of the main disconnecting mean for the normal power. Simply, I'm trying to understand the NEC rule; Can I power the fire pump from a feeder circuit (instead of taping a head of the main service disconnect) if I have another source,such as the generator, feeding the fire pump via ATS? Tahnks,
 
I can only think of 1 data center I have done in a while that had the fire pump tapped before the utility disconnect. The fire pump ATS was fed from ahead of the utility disconnect and then by the facility generator.

99% of the time, the fire pump ATS has been fed from 2 sources AFTER the utility disconnect (NOT tapped ahead of the main service disconnect). The dual sources of power along with the back up generators have been approved by the AHJ.
 
rich000 said:
I can only think of 1 data center I have done in a while that had the fire pump tapped before the utility disconnect. The fire pump ATS was fed from ahead of the utility disconnect and then by the facility generator.

99% of the time, the fire pump ATS has been fed from 2 sources AFTER the utility disconnect (NOT tapped ahead of the main service disconnect). The dual sources of power along with the back up generators have been approved by the AHJ.
Click to expand...

I've never seen a fire pump that wasn't fed from a separate main than the building service.

But I haven't seen any where the service is 13.8KV. That might make a difference. I'm not sure where the service point is.

In the end, I believe the code says the supplies must meet the approval of the AHJ. I would ask before I went too far with the design.

Steve
 
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