# 208 to 277v lighting



## RTD (Oct 13, 2014)

Hi Gentleman 
I have 3 phase coming into the building, I need to Light 277 Volt Lights 20 amp Breakers, what is the best way? do I need a step up transformer and if So! what ones are best? how big, Etc. Thank You.


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## Pete m. (Nov 19, 2011)

RTD said:


> Hi Gentleman
> I have 3 phase coming into the building, I need to Light 277 Volt Lights 20 amp Breakers, what is the best way? do I need a step up transformer and if So! what ones are best? how big, Etc. Thank You.


What electrical experience do you actually have? Your info says commercial/telecommunications.

Answers to questions like this are easily ascertained by someone with requisite experience.

Pete


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## 480sparky (Sep 20, 2007)

RTD said:


> Hi Guy's we want to change Florescent to 3 phase 277v Lighting 20 amp what is needed from our 3 phase 208? do we need a step up transformer?



What is the compelling need to change the lighting from the existing 208v to 277?


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## Vintage Sounds (Oct 23, 2009)

RTD said:


> Hi Guy's we want to change Florescent to 3 phase 277v Lighting 20 amp what is needed from our 3 phase 208? do we need a step up transformer?


#1 you need an electrician


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## denny3992 (Jul 12, 2010)

Ibtl


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## Wirenuting (Sep 12, 2010)

ibtl..
Don't go with 277 lighting, it has a higher ringer equivalent.


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## 480sparky (Sep 20, 2007)

I'll toss in my theory about the thread.

This is someone who was told that 277v lighting will save energy over 208v lighting. Sorry, but that isn't an ammeter on the side of the building.

The only savings 277v has over 208v lighting is less wiring costs up-front. If you want to convert 208v lighting to 277, the labor and materials needed will never be recouped in energy savings as there won't be any.


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## Vintage Sounds (Oct 23, 2009)

480sparky said:


> I'll toss in my theory about the thread.
> 
> This is someone who was told that 277v lighting will save energy over 208v lighting. Sorry, but that isn't an ammeter on the side of the building.
> 
> The only savings 277v has over 208v lighting is less wiring costs up-front. If you want to convert 208v lighting to 277, the labor and materials needed will never be recouped in energy savings as there won't be any.


If you changed a bunch of 120 or 208v lighting to 277v and thus reduced the load on a transformer, would you have less transformer losses? Or would you have to change to a smaller transformer to notice much of a difference?


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## 480sparky (Sep 20, 2007)

Vintage Sounds said:


> If you changed a bunch of 120 or 208v lighting to 277v and thus reduced the load on a transformer, would you have less transformer losses? Or would you have to change to a smaller transformer to notice much of a difference?



Well, 120 and 208 are usually derived directly from the POCO or from a 480v source. If there's 480v on-site, that means there's 277v as well. And usually, 480v services supply 277v lighting. The 120/208v transformer is for 'normal' receptacles and small 3ph. loads.

I'm assuming the OP has 120/208 service. Upping to 277v can be done with a transformer, but any energy savings that might be obtained will have a forever ROI.

Changing the service to 480/277 is another option, but now you're adding a 480-120/208 transformer into the mix. Again, ROI would take aeons.


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## Electric_Light (Apr 6, 2010)

Electronic ballasts are often 1-3% more efficient on AC 277v than 120v.


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## Vintage Sounds (Oct 23, 2009)

480sparky said:


> I'm assuming the OP has 120/208 service. Upping to 277v can be done with a transformer, but any energy savings that might be obtained will have a forever ROI.
> 
> Changing the service to 480/277 is another option, but now you're adding a 480-120/208 transformer into the mix. Again, ROI would take aeons.


I was assuming the opposite - that the building probably has a 277/480 service but was designed with 120v lights because I see a lot of that lately.

Could be the other way around too though, like you said.


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## RTD (Oct 13, 2014)

I Have 8 - 100 amp services Did not want to add or change to a 277/480 disconnect just bought building and have 30 years to grow, I need to add over 350 lights small increments of 60 each at a time 50, 000 sq ft Building. 

12 GA. verses 10 GA. EMT 1/2 inch verses 3/4" 2 " inch verses 3" EMT to junctions a lot smaller on and on, as for the savings Young and have time on my hands.

Thank all of You


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## wildleg (Apr 12, 2009)

you are not going to know what your best ROI is going to be without doing a little research. As others mentioned, deciding willy nilly to go with 277 might not be in your best financial interest. You might, for example, swap out the existing with LED, or even just add led, or t5, and be better off. If you don't do your homework you will never know. good luck with it.


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## 480sparky (Sep 20, 2007)

RTD said:


> I Have 8 - 100 amp services........ 2 " inch verses 3" EMT to junctions.......


Say what?......... you're using 2" and 3" EMT for *lighting circuits*? And the *services* are only 100a?


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## wildleg (Apr 12, 2009)

480sparky said:


> Say what?......... you're using 2" and 3" EMT for *lighting circuits*? And the *services* are only 100a?


yeeehaw. and you were the one that didn't lock the thread . :laughing:

(I don't even want to know why he needs 2" for the feeds)


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## Going_Commando (Oct 1, 2011)

480sparky said:


> Say what?......... you're using 2" and 3" EMT for lighting circuits? And the services are only 100a?


Well duh, he is a diy'er that doesn't know anything and wants professional advice.


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## Cincycaddy (Sep 18, 2014)

Slightly OT but how often do you guys see 120V lighting when 480/277V is available? I had a client last year who insisted on 120V lighting in a new facility where there was 480V service available. Ended up putting in alot more circuits and larger wire to overcome voltage drop.


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## denny3992 (Jul 12, 2010)

480sparky said:


> Well, 120 and 208 are usually derived directly from the POCO or from a 480v source. If there's 480v on-site, that means there's 277v as well. And USUALLY, 480v services supply 277v lighting. The 120/208v transformer is for 'normal' receptacles and small 3ph. loads. I'm assuming the OP has 120/208 service. Upping to 277v can be done with a transformer, but any energy savings that might be obtained will have a forever ROI. Changing the service to 480/277 is another option, but now you're adding a 480-120/208 transformer into the mix. Again, ROI would take aeons.


 Ive seen a few where the neutral didnt leave the xfrmr.... Oh and there was single pole brkrs in the 480 panel? Huh? Grnd carried back to xfrmr... And it was in a wwtp!


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## Meadow (Jan 14, 2011)

Ibtl


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## Dennis Alwon (May 9, 2009)

I have decided to close the thread until the OP responds about his training. He can pm me.


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