Fire pump

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hardworkingstiff

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Wilmington, NC
Looking at some plans and there is a feeder going from the UG PoCO transformer to the Fire Pump Controller. The schedule calls for (3) 4/0 conductors (3-phase 480-volt) between the transformer and the disconnect. It seems odd that no ground is installed.

The Fire Pump Controller will have ufer ground and ground rods and building steel ground.

This seems .... well.... not quite right. Shouldn't there be a direct path back to the transformer for a phase to ground fault? Usually that is in the neutral conductor, but since a neutral is not used then it's not installed. Isn't there a section that requires a neutral to be brought to the service disconnect (I guess that would be for the grounding)? Now that I post this, I guess the Fire Pump Controller needs to be service rated.

This is my 1st experience with a Fire Pump system and any heads ups from you guys would be greatly appreciated.
 
hardworkingstiff said:
Looking at some plans and there is a feeder going from the UG PoCO transformer to the Fire Pump Controller. The schedule calls for (3) 4/0 conductors (3-phase 480-volt) between the transformer and the disconnect. It seems odd that no ground is installed.

The Fire Pump Controller will have ufer ground and ground rods and building steel ground.

This seems .... well.... not quite right. Shouldn't there be a direct path back to the transformer for a phase to ground fault? Usually that is in the neutral conductor, but since a neutral is not used then it's not installed. Isn't there a section that requires a neutral to be brought to the service disconnect (I guess that would be for the grounding)? Now that I post this, I guess the Fire Pump Controller needs to be service rated.

This is my 1st experience with a Fire Pump system and any heads ups from you guys would be greatly appreciated.
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Do you mean GROUNDED Conductor?

If there are only ungrounded conductors supplying this service disconnect, it will be a violation. 250.24(C)
 
Yes they missed it, 08' shows the index as fire pump, grounding as 250.112(L) or (M).

You'd have to put it at the trannie...
 
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