480 service

[Ralphie]

A 480 volt service without neutral used to power refrigeration equipment. Does the NEC require ground fault detection lights

 

[pete m.]

250.21(B) requires ground detectors

Pete

 

[jim dungar]

Ground detection is needed if it is actually an ungrounded system, (i.e. >277V L-G).

Without knowing all of the details, be aware that most utilities, now, only supply 480Y/277V services without a 'neutral', in which case ground detection would not be required.

 

[chris kennedy]

Without knowing all of the details, be aware that most utilities, now, only supply 480Y/277V services without a 'neutral', in which case ground detection would not be required.

Typo?

 

[jim dungar]

Typo?

No.

The utility supplies a 480Y/277V service with a grounded conductor, there is no requirement that this be used as a 'neutral', although it does need to be brought to the service equipment. From the service equipment only 3W + G are available to the load. Usually Listed service equipment with a 'load neutral' requires a removable N-G bonding jumper and a neutral isolation method.