Got 480V want 277V

[Chayvo]

I have a 480V supply and need to connect a light fixture which can be wired 277V. It was suggested to take a phase and ground to get 277V,Ive never done this before, is this a safe accepted method?

 

[ActionDave]

More information is needed. What is your voltage system. You need a 480/277 wye (star) for this to work.

 

[infinity]

Corner grounding an ungrounded 3? Delta system will not give you 277 volts. When measuring phase to ground it will give you 480-0-480 volts.

 

[Canton]

If he has a 480/277 wye distribution, he may be impling that someone told him to "rob the ground" because no neutral is available where the light is to be installed. Which is obviously a code and serious saftey violation.:blink:

 

[Chayvo]

Thanks Canton,
That is the system and I thought something wasn't right.

 

[Chayvo]

Canton,

Where wouldI find this in the code to be able to support this?

 

[Jraef]

Canton,

Where wouldI find this in the code to be able to support this?

Don't have my code book for a direct reference, but it's the part(s) about not using the ground connection as a current carrying conductor. Neutral is a current carrying conductor, even though it is common to ground at the service entrance point. For you to use 277V at a lighting load from a 480/277V 4wire system, you will need the Neutral conductor run out to it from the service panel. You cannot just connect one phase to ground.

 

[Pharon]

Check out 250.24(A)(5). If you decide to use an equipment grounding conductor as a neutral (grounded conductor), then it can no longer be an EGC, and that's assuming its insulated non-green wire (and not bare):

(5) Load-Side Grounding Connections. A grounded
conductor shall not be connected to normally non?current carrying
metal parts of equipment, to equipment grounding
conductor(s), or be reconnected to ground on the load side of
the service disconnecting means except as otherwise permitted
in this article.

 

[Chayvo]

Thank's for your input and time.