# A very unusual lighting senerio.......



## Ghostnotes1221 (Oct 20, 2017)

I begged and pleaded with the client but they would not budge. I am designing lighting for a gas plant (industrial). The unusual part of it is the lighting is 120v LED. 53 lights with the longest run being 1600ft....yes you read right 1600ft. They had sent me the information with a general layout. The lights are 100w equivalent pulling around 43w ~.35A. So i rounded it up to .5A per light to be safe. The 10 outermost lights ~1600ft calls for a #4 AWG to cover voltage drop. They will also be on a lighting contactor. So i figured on setting a box with the photocell and lighting contactor at 1200 feet and covering the rest of the distance, ~400 feet with #10.

As i get closer, i am keeping the same size wire but adding lighting to the other circuits/Lighting contactors. I also was told this was 120v 3 conductor with ground.

HOWEVER when i show up i am informed that only is it not 120v, it is in fact 240v single phase. At this point I think I have 2 options and is my question....

I based my run off of 120v,(3c with ground) meaning 1 hot, 1 neutral and 1 ground. Does this now mean i can double my lighting capacity at the same distance since i will be running 240(4c with ground 120v line to neutral)? If so, i plan covering some lighting that is around 1100ft coming back towards me, and using fewer lighting contactors.

Thanks!!


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## frenchelectrican (Mar 15, 2007)

Ghostnotes1221 said:


> I begged and pleaded with the client but they would not budge. I am designing lighting for a gas plant (industrial). The unusual part of it is the lighting is 120v LED. 53 lights with the longest run being 1600ft....yes you read right 1600ft. They had sent me the information with a general layout. The lights are 100w equivalent pulling around 43w ~.35A. So i rounded it up to .5A per light to be safe. The 10 outermost lights ~1600ft calls for a #4 AWG to cover voltage drop. They will also be on a lighting contactor. So i figured on setting a box with the photocell and lighting contactor at 1200 feet and covering the rest of the distance, ~400 feet with #10.
> 
> As i get closer, i am keeping the same size wire but adding lighting to the other circuits/Lighting contactors. I also was told this was 120v 3 conductor with ground.
> 
> ...


Is there is other voltage option on those LED luminiares ? 

I would go the 240 volts or 277 volts if possible. 

Get all the specs with the voltage and numbers of lumiaires that required to run on 120 volts and other voltage if possible. 

actually when you double the voltage on that circuit the distance can go more than double very easy due the voltage drop is lower on higher voltage side. 

What type of LED lumiaire what you are refering to it ?? a pole top or what ? 

1600 foot is nothing for me due I have ran much longer than that. 

Most of the parking lot lumaiaires what I designed are at 240 volts or higher that how I can avoid some perksy issue with voltage drop. 

You can run in 4 conductors format in single phase ( two line and netural and ground conductors ) or 5 conductor if you going snag from three phase source.

With 240 volt circuit you can able downsize the conductor a little ( one size smaller ) but pay attetion to line to netural load that is the only item it will bite ya.


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## Ghostnotes1221 (Oct 20, 2017)

Unfortunately I am stuck with 240 V Single Phase. The transformer was already here before I arrived. I have no idea why they will not go 277. That would have made my life so much easier . I thought about the neutral load but I figured as long as I stayed well below the average of the conductor caring it, I will be ok.

The lights are just general floodlights Class 1 division 2. About 8 feet off the ground spaced 60' apart. 110w equivalent. 
I thought about downsize But I got to thinking even further and figured it was still 120 to neutral for either so im not really doubling my voltage, just adding a parallel hot in respect to what i thought I had. That's when I realized the 10 lights at the end of the run were only half now and I can use the other line the same way.


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## telsa (May 22, 2015)

Truly LONG runs ... one starts thinking of Series circuits -- as in airport runway lights.

You've got me all crossed up.

Client has a FAT wallet.

The scheme ought to be TOTALLY engineered.

Yet, you are expected to engineer it.

Jumping to #4 seems absurd on its face... as in NOT something that any EE would pencil in.

BTW, it's no biggie to use a transformer to bump 240VAC up.to 480. 

Bumping merely to 277VAC makes ZERO sense.

As for the fixtures, 1,600 feet is quite a run -- and means that you ought to look at 480VAC LEDs.

For, you're talking about 1,600 feet out and 1,600 feet back on the neutral.

UP size the neutral, BTW.

You won't regret it.

( Solid state power electronics send serious harmonics back down on the neutral. Give them a freeway. )


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## Cow (Jan 16, 2008)

You sound like you're out of your comfort zone. 

Is there a reason the gas plant isn't using an electrical engineer with proper drawings for their projects?

We do similar projects all the time with long runs such as these. There are a few tricks to making it easier and getting it done correctly but it's far easier in person than typed in a post over the internet.

Is there no one local you can lean on for guidance who can put their own eyes on the project?


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## LuckyLuke (Jun 1, 2015)

Never ever have I seen an electrician "design" anything on a oil / gas site, this seems like an extremely odd situation and to be honest based on the type of business you are dealing with I would tell them that you are hiring a EE to assist you (on their penny of course). I "design" many things but never would I in a oil / gas industry.


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## Electrical-EE (May 4, 2017)

Is your client an engineer?


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