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#190025 - 11/03/09 05:05 PM Fire Pumps 695  
Yoopersup  Offline
Member
Joined: Mar 2003
Posts: 822
Michigan
Em. Generator Breaker off that feeding service rated Firepump controller/Transfer Switch..
Service from Transformer feeding service rated fire pump controller/transfer switch (same).
From Generator Since breakers on Gen. Set its a Feeder.
From Transformer to to Service rated control/Transfer switch its Service conductors.
Generator side its 3 hots & Ground.
Transformer side its 3 hots & Neutal.(250.24C)
Neural & Ground terminate together at this point ????

Any one else run into this???
Yoopersup


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#190054 - 11/04/09 03:04 PM Re: Fire Pumps 695 [Re: Yoopersup]  
SteveFehr  Offline
Member
Joined: Mar 2005
Posts: 1,205
Chesapeake, VA
Originally Posted by Yoopersup
Em. Generator Breaker off that feeding service rated Firepump controller/Transfer Switch..
Service from Transformer feeding service rated fire pump controller/transfer switch (same).
From Generator Since breakers on Gen. Set its a Feeder.
From Transformer to to Service rated control/Transfer switch its Service conductors.
Generator side its 3 hots & Ground.
Transformer side its 3 hots & Neutal.(250.24C)
Neural & Ground terminate together at this point ????

Any one else run into this???
Yoopersup
If it's a delta generator, I hope it's a delta pump. If it's a delta pump, you don't need a neutral. 250.24(C) doesn't apply to delta panels, as the AC system is not grounded at any point.

Easy answer: don't run the neutral.


#190058 - 11/04/09 04:39 PM Re: Fire Pumps 695 [Re: SteveFehr]  
Yoopersup  Offline
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Joined: Mar 2003
Posts: 822
Michigan
480/277 Volt System at both Generator & Service Thus Neutral required per 250.24c to ist disconnect switch per code.Since Feeder Neutral is not required only equipment gr. But Service requires Neutral.
Yoopersup



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