Street Lighting Design - Electrician Talk - Professional Electrical Contractors Forum

chenley · 11-19-2009, 10:53 PM

This is for the same job as the type of 3R panel I was inquiring about a couple of days ago.

The PoCo here is planning on running 4/0 triplex to feed streetlights off of a 100A DP breaker from the panel. Obviously, the first thing I thought was that 4/0 will not fit in a 100A SQD QO breaker although they can easily use Polaris fittings to reduce the wire size to fit.

What's got me is this just seems to be a poor design. I've never done street lighting or parking lot lighting and really do not want to so I guess I can't really make that assumption

.

This has got me thinking though; Is there anything in the NEC from preventing a 100A DP breaker from feeding however many streetlights are going to be installed? I've searched and searched and can't come up with anything. Seeing the earlier post at MikeHolts about parking lot lighting utilizing multiple 20A breakers got me thinking about this.

rdr · 11-19-2009, 11:13 PM

How far is the farthest streetlight from the panel? Obviously they are allowing for some V drop. 4/0 in a 100 A breaker is pretty darn tough though. If you reduce it with polaris taps and smaller wire doesn't that somewhat defeat the purpose of upsizing the triplex to begin with?

chenley · 11-19-2009, 11:26 PM

I'm just repeating what I was told over the phone. Meeting with the industrial park engineer tomorrow to go over other things with the design and what they are trying to accomplish.

This project just came out of nowhere and hit me in the back of the head. They don't even really have a plan for what they are wanting to do and things keep getting added to the mix every time I talk to the guy, albeit minor things like irrigation system hook-up & landscape lighting.

I'm leaving the street lighting up to the PoCo, as I said I don't really want anything to do with that side of things. Just trying to cover all my bases so I don't have to go back and change things. I really hate it when that happens even if it is on someone elses dime.

te12co2w · 11-20-2009, 09:10 AM

Quote:

Originally Posted by rdr

How far is the farthest streetlight from the panel? Obviously they are allowing for some V drop. 4/0 in a 100 A breaker is pretty darn tough though. If you reduce it with polaris taps and smaller wire doesn't that somewhat defeat the purpose of upsizing the triplex to begin with?

I don't think the short length of smaller wire will influence the voltage drop calcs very much.

Grimlock · 11-20-2009, 10:00 AM

The larger size wire is for voltage drop and they will most likely fuse at the poles.

chenley · 11-20-2009, 04:24 PM

Went out there today and walked it out, there's nine stakes in the ground for street lights and it's about 850' to the last pole. Did a rough calculation earlier with like 80A and came out with about 900' of 4/0, so there about spot on.

@rdr
It'll be about 6"-10" of 1/0 or 2/0 going from the breaker to the Polaris
to 4/0, so it won't affect VD much at all.

@Grimlock
I'm hoping they fuse at the poles, I'll recommend it to them, but that's their show I'm just giving them a breaker/disconnect.

chenley · 11-21-2009, 12:24 AM

I'm thinking that 210.23(D) would prevent the PoCo from installing the street lighting on a 100A DP breaker.

LawnGuyLandSparky · 11-23-2009, 02:30 AM

Quote:

Originally Posted by chenley

I'm thinking that 210.23(D) would prevent the PoCo from installing the street lighting on a 100A DP breaker.

No it won't.

DipsyDoodleDandy · 12-24-2009, 10:33 AM

let us know what happened

Grimlock · 12-24-2009, 11:59 AM

Most of the light poles I have worked with in these situations had inline fuses, usually 10A in the handholds.

Similar to these but crimp on, sometimes they where dual also:

chenley · 12-24-2009, 01:29 PM

Quote:

Originally Posted by DipsyDoodleDandy

let us know what happened

Drove by it yesterday and the PoCo hadn't even hung the transformers on the pole. Did talk to the engineer and the pole that they are getting come with fuse holders. Works for me.

BGOLPMP · 02-26-2010, 11:48 PM

8 poles 900 feet???? Why wouldn't you drop the wire size down the further down the line you go? What kind of lights are these? 100A breaker seems to be tons of overkill. I install highway lighting for the state dot and we have a single phase 240/480 single phase service and all lights run off of 240 volts. We fuse the lights at 5 amps (the fuse in the hand hole) and the breakers are 30 amps in the mail pannel. We will usually have 8 lights and more on one circuit. The lights are 150-400 watt HPS.
Also if you don't fuse the lights at the poles, what are you going to hook the lights up with????? 4/0???? lol I would like to see someone wire the lights with 3awg that would suck!!!!! Ilscos on top??? Split Bolts?

Just my $.02

Andy

cdnelectrician · 02-27-2010, 12:01 AM

Quote:

Originally Posted by Grimlock

Most of the light poles I have worked with in these situations had inline fuses, usually 10A in the handholds.

Similar to these but crimp on, sometimes they where dual also:

They also serve as a handy dandy disconnect when you have to service the pole light

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