Poles not working

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frogneck77

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Shelton,CT
I get a call today for a shopping center-5 poles not working, about 20 400W fixtures in a large parking lot. First I start at the source- 200A 277/480V panel controlled by a contactor feeding all the site lighting. Everything looks fine,contactor pulling in. voltages,etc. I go to one of the poles not working and Im testing 200V to ground on each of two phase legs coming in(480V fixtures), and nothing between phases. At some of the other poles Im reading 136V to ground on one leg and 205 on the other. Im thinking a loose connection at some point-Im used to seeing similar reading with a bad neutral, but there is no neutral for these lights. Any ideas?
Bill
 
Do you have an original plan or as-built to go off of to see which lights are on that circuit? If you can find out how it was wired to begin with, you're ahead of the game.

I would also see if there's a ground box somewhere that may contain splices.
 
I go to one of the poles not working and Im testing 200V to ground on each of two phase legs coming in(480V fixtures), and nothing between phases.
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Sounds like you lost a phase in the home run.

Find the HR pole or JB, disconnect and test voltage.


I am thinking that the odd voltages are from the backfeed going thru all the ballasts.
 
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frogneck77 said:
I get a call today for a shopping center-5 poles not working, about 20 400W fixtures in a large parking lot. First I start at the source- 200A 277/480V panel controlled by a contactor feeding all the site lighting. Everything looks fine,contactor pulling in. voltages,etc. I go to one of the poles not working and Im testing 200V to ground on each of two phase legs coming in(480V fixtures), and nothing between phases. At some of the other poles Im reading 136V to ground on one leg and 205 on the other. Im thinking a loose connection at some point-Im used to seeing similar reading with a bad neutral, but there is no neutral for these lights. Any ideas?
Bill
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I operate a bucket truck servicing light poles at several major shopping centers.

Another contractor was hired to install some smaller light poles in a well-to-do part of the shopping center. While digging, they cut the conduit going to several 480v light poles. They set a junction, several actually, and tied wires back together. We get a call that the 100 main breaker tripped. Basically when they tied the wired back together they didn't ream any of them out and phase them. They had several phases buck and tripped the main.

These are 480v light poles on a timer-controlled contactor system. We spent several days reaming out from pole-to-pole. Found out where the feeder went. We even unhooked all but one the the phases and were getting backvoltage to the contactors on 6 other wires. We were getting somewhat the same reading you are. Long story short, we pulled in the feeder wire (7- #8 250') to the first pole. It took seeral hours to pull out the old wire. When we got all the wires out there were several spots that the wires burnt up. There was water in the pipe and that caused us, we believe, to get some rather unusual voltages. We also had several other poles that were cycling through. After we pulled in the new wire and fixed a few other issued caused by the other contractor, the poles were lit up.


Had another place that a conduit broke and the wires were burnt, all but one. Were lucky get them pulled out. Pulled in new wire to those as well.

If you get some crazy voltages and you can't get continuity from phase to phase from the wires in the pipe, pull in new wire.

Stuff happens.
 
BackInTheHabit said:
I operate a bucket truck servicing light poles at several major shopping centers. ...

Stuff happens.
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Nice post, BackInTheHabit. You know some stuff after all. I was starting to think you got the just link to stuff and zip the lip gene from Joe Tedesco.
 
I was hoping it was just the contactor initially, but it looks like we'll be spending some serious time there tomorrow. The property manger has no as builts(I asked today). I opened up all of the poles not working, tested strange voltages, cleaned up all the connections, and got nowhere.I am renting an underground circuit tracer tomorrow and I will take apart the connections at each pole to try to trace the route of the wires. I found no ends in any of the poles I looked at. The pipes are coming out of the lighting panel into the concrete and I cant find any handholes,manhole covers, JB,s anything!. It should be an interesting day tomorrow
 
frogneck77 said:
I...and I cant find any handholes,manhole covers, JB,s anything!. It should be an interesting day tomorrow
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If thet lot's ever been repaved, unlike streets, they normally just pave right over them. That's one reason I try to only do handhole boxes if there's grass islands. Or course, they often sink in the dirt over time too.
 
mdshunk said:
Nice post, BackInTheHabit. You know some stuff after all. I was starting to think you got the just link to stuff and zip the lip gene from Joe Tedesco.
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I could take that as in insult, but I won't.

I may not know everything, I'm learning something new everyday.

Regarding the links, Just trying to be helpful.
 
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480sparky said:
Do you have an original plan or as-built to go off of to see which lights are on that circuit? If you can find out how it was wired to begin with, you're ahead of the game.

I would also see if there's a ground box somewhere that may contain splices.
Click to expand...

Don't count on the as built plans to be accurate.
 
frogneck77 said:
Any suggestions as to the mo?st timely troubleshooting method in this situation?
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Don't try to overthink the problem. If it doesn't make any sense, there's a logical reason. You can only aggrevate yourself by trying to think "WHY is it doing this?."

Anyway: That's why they call it troubleshooting.
 
Sounds like one ckt is not working. Amprobe all wires with all ckts on and timeclock/photocells bypassed and determine which have a load on them. Problem is from contactor to 1st polebase for ckt from info given should be a simple fix. Dont go on a wild goose chase if ckt is carrying current it is ok and go to the ckt with no load. Trust your knowledge. Look for evidence of sawcutting new landscaping anything that involves digging that recently happened.
 
there few ways i can find bad wire most common is use the thumper or megger once i know the wire is no good then what i do i go with underground wire locator i can ring them up pretty easy if they are in PVC conduct but however if in rigid it little differnt to find it.

the reason i don't follow the bleuprint or layout plans because over the time it will change and few case i can find buried junction box on few areas it is no fun at all.

Merci,Marc
 
if you don't know the 1st pole fed (assuming no JB's), just pick a pole, disconnect feed in & out and chk voltage and repeat (I would start where I think the 1st pole is fed). Odd voltage may be wires burnt UG.
 
Can you actually pull & move the wires coming into your pole bases?
How far from the panel to what may be your first pole and is that wire
free to pull? What type of conduit are they run in? Sounds like you may be doing some excavating.
Could you rent a generator and backfeed from the furthest pole?
 
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