voltage drop

[sparkympk68]

I'm a new member who would appreciate some advice. I have a project to wire pole lights (security motion sensor controlled 175watt halogens totalling around 19 amps @120v.) The distance from panel to furthest pole is about 600 feet. I tried the voltage drop calculator -something like #1awg .This is definately not cost effective.Does anyone know if acceptable voltage drop can be higher than 3% (branch circuit) and still opperate the lights ? Thanks, sparkympk.

 

[StephenSDH]

When you do voltage drop you don't want to enter in 19A at 600 feet because it will calculate a large wire size. In reality your load isn't at the end of 600 feet. It sounds like you have around 13 lights. So it would be 19 amps to the first light, and then 17.5 to the next light... It might make sense to run a larger gauge wire to the first light and then reduce gauge as needed. Sounds like the best thing to do is find a 240v light.

-Steve

 

[charlie b]

A little extra homework can save you a bit of money. All you need to recognize is that the entire 19 amps is not going to go all the way to the last light 600 feet away. But the entire 19 amps will flow from the breaker to the first light. After that, each time you pass one light, the amount of current flowing towards the next light gets smaller.

So build yourself a little table. Let me suppose there are 13 lamps, so let?s say they are 40 feet apart, but the first one is 80 feet from the breaker. So you have 19 amps to the first light, a distance of 80 feet. Try for a small voltage drop along each part of the run, let us say .25%. I get a conductor size of 2/0.

Now you have only 17.5 amps going 40 feet to the next light. I get a conductor size of #1.

Now you have only 16 amps going 40 feet to the next light. I get a conductor size of #2.

It may not be practical to change wire sizes at each junction. But I think you can see the process that is available to you.

Welcome to the forum.

 

[William1978]

What size ground wire do you plan on pulling?

 

[bob]

You could use 240 volts and connect the lites line to neutral. You may also look at a higher voltage, 277 or 480 volts, and significantly reduce the wire size.

 

[sparkympk68]

voltage drop on lights

voltage drop on lights

:smile:Thanks for the help, I will try to locate some 240v. fixtures with motion sensors. I do see how 1.5 amps are used @ each fixture(@120v.) I'll lower the wire size as I get futher away!