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maintenance dude
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Join Date: Oct 2007
Posts: 17

277 volt lighting

10/04/2007 7:34 AM

Can someone tell me how/if you can install a 277 volt lighting fixtures to 480 volt supply.
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PWSlack
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#1

Re: 277 volt lighting

10/04/2007 7:43 AM

Is there a 'neutral' wire, electrically in the middle of each of the 480V phases?

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maintenance dude
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#2
In reply to #1

Re: 277 volt lighting

10/04/2007 7:58 AM

I don't think so. There are 480V HID fixtures on the circuit now. I wanted to add fuorescent fixtures to the circuit if possible. 277 ballast are more readily availble then 480V.

Thanks
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PWSlack
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#3
In reply to #2

Re: 277 volt lighting

10/04/2007 8:01 AM

Then the answer is no, they can't, because of the absence of the neutral conductor.

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maintenance dude
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#4
In reply to #3

Re: 277 volt lighting

10/04/2007 8:08 AM

So if I had a neutral wire, I would use one leg of the 480V and the neutral to get the 277V. Correct?

Thanks for the help
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PWSlack
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#5
In reply to #4

Re: 277 volt lighting

10/04/2007 8:17 AM

Correct.

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Stinky Pete
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#7
In reply to #4

Re: 277 volt lighting

10/04/2007 8:50 AM

If you need some, I've got some 480V ones in one of my skips in Basildon. Come and get them if you like. £5 each and you take them away? <Splutter>

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NoSciFi
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#9
In reply to #4

Re: 277 volt lighting

10/04/2007 11:25 PM

If you want to use a wall switch, it has to be a 120 v operated relay for the 277. I'm sure the 480mis controlled by a relay already, but a separate switch would require the relay. The ground bus in your panel should be the neutral, except in the case of an isolation transformer. If ou plan on more than a single light in the circuit, then you shoould have an equal number on each phase, either 2 or 3 phases. They can share a neutral, and 3 phase will only carry harmonics, but they can be more than the neutral load, so don't push the loading.

RichH

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Bill
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#6
In reply to #2

Re: 277 volt lighting

10/04/2007 8:24 AM

277 line to neutral; 480 line to line. Very common. Ask an electrician.

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Mr. Truman Brain
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#8
In reply to #6

Re: 277 volt lighting

10/04/2007 12:04 PM

Yes, It's very common! Or you could wire up a few in series! (I think that would work but I have never tried it!)

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4leafclovis
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Join Date: Sep 2007
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#10

Re: 277 volt lighting

10/04/2007 11:36 PM

The 277 voltage would have to come from a three phase transformer that is connected in a 277/480 WYE connection which would give you 277 from the neutral to any of the hot legs. This is to better balance the load on the transformer.
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bubbapebi
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#11

Re: 277 volt lighting

10/04/2007 11:53 PM

It looks like this...

http://www.patchn.com/wye.htm
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nascon
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India - Member - PROFESSIONAL Engineering Fields - Power Engineering - electrical planning - designing

Join Date: Sep 2007
Location: Ahmedbad, Gujarat
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#12

Re: 277 volt lighting

10/05/2007 7:43 AM

provide 480 v/ 277 volt transfomrer of equal VA

nascon
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dda
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Join Date: Jul 2007
Location: Los Angeles
Posts: 23
#13

Re: 277 volt lighting

10/05/2007 9:53 AM

IF you only have one circuit than I don't know of a good way.

If you have a bunch consider this;

I see this in all the data centers - They use a 480 volt 3-phase, 3-wire Primary to 277/480 Volt secondary, 3-phase, 4-wire transformer - you create a neutral. I think the smallest is a 15 kVA. The output feeds your new lighting panel. You would ground the neutral in this panel, or the transformer. This separately derived system with help you avoid building ground fault issues
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Users who posted comments:

4leafclovis (1); Bill (1); bubbapebi (1); dda (1); maintenance dude (2); Mr. Truman Brain (1); nascon (1); NoSciFi (1); PWSlack (3); Stinky Pete (1)

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