Fire Pump Grounded Conductor required

[kvolt]

We have a utility transformer providing service to the building at 277/480 volt, 3 phase 4 wire. We also have, from this same transformer, a second service strictly for a fire pump. Is a grounded conductor required to be installed when the fire pump is 480 volt 3 phase only.

 

[david luchini]

Yes, it is. See 250.24(C).