I went out to an steel whole seller plant. In the yard they have a huge crane that moves and loads steel. which is being fed by #2AWG from a 225Amp three phase breaker. Next to that panel they have another panel with a 20Amp/3 phase breaker that powers 277Volt lighting. When i opened both panels i did not see a grounded(neutral) conductor. The way they are getting the 277 from 480 is they are using the grounding in this case the frame of the panel.

This is clearly in violation. Right?

Or am i missing something here?

Thanks
Edward

What makes you believe the lighting is 277, it might be 480 volt and what you think is neutral is really the EGC.

But if it is 277 lighting run from a 480 panel with no neutral, yes it is a serious violation.

The reason i know it is the neutral because there are three colored conductors and one grounded(neutral) going to the lighting fixtures. Besides there are photo cells that control the lighting fixtures which are rated for 277 and have a neutral conductor.

Thanks
Edward

Not having seen the installation it sounds like a violation.

The reason I asked about the voltage is that it is common to run site lighting from a 480 volt 3 pole breaker. Some fixtures on phases A - B some on B - C and others on C - A.

There would be no reason to use a 3 pole breaker if these lights are 277 volt, three single pole breakers would normally have been used for this.

I would say it is bad to assume that just because you see a white wire that it is a neutral. Although using a white wire for the EGC would also be a violation.

The photo eyes definitely sound like a violation as I they do use a neutral as you pointed out.

You could Mickey Mouse three (or even 2) 277 volt single pole photo eyes to control a 3 phase 480 volt feed. But that would be a violation also.

Bob

I saw this type of Mickey Mouse set up, too. I assumed that it was a result of not being able to get a 480 volt photo cell.