Pole light problem..

[sparky723]

I got called out to the prison were I work Last night during a hard rain. On the phone they stated that 5 pole lights were out. I arrived and sure enough all 5 were out. BTW, on top of each pole light, there is a 1000w and 2 400 w fixtures. (30' poles). Anyway, I checked the panel and the breaker for these 5 poles was tripped. I reset it and 3 of the 5 came on (lets say A,B, and C). Then after a short time, they went off. I rest the breaker again and this time in the contactor box (nearby the panel) I heard a POP! I went back to look at the 5 lights and the lights A, B, C were back on. While I was in the elec. room, some people were watching the lights and said "the middle light (1000w) on pole C arc'd" Later stating there was a bright blue flash...With it pouring down rain I decided to clock out and go home. On the way out I talked to the mobile patrol who just happened to be watching the lights at the base. He said "It (pole C) arc'd at the bottom". I told him "OK, I'll check it out in the morning."
Today, I went to the base of pole C (middle of the 5 poles) and also where the feed comes in for these 5 poles. I noticed the wires (2 hots,1G) going to poles D and E were burned in two. I made neccesary repairs and checked for voltage at the pole C. I got 283 on each to ground. I went and check for power (with tick) at base of poles A and B. I showed power at each pole. As it was getting close to the end of the day, I energized all 5 poles , but no light on any of the poles lit up. (I gave them an easy 15-20 mins.) The lights are metal halide I believe. There was hardly any lighting during the rain, if any.
SIDENOTE: the externally ran conduit from pole C to poles D and E had been previous hit by tractor or something, leading to the shorting of the wires and me having to re-wire this section of the wiring to poles D and E.

Does anyone think the problem might be up top somewhere within the lights?
I feel I have troubleshot most problems on the ground.

Please help, sparky 723:-?

 

[g@friendly]

I can see the paper now. Prison break electrician involved...

well I would separate each light and take amp load at each light if you are trying to avoid having to go up to test the light that might help. Good luck

 

[bpk]

Did you check to see if the lights have a photocell on top. This may sound stupid but its got me before.

 

[guschash]

I just had a repair and it was the light fixture, it shorted out. But your job sounds like it might be on the ground. If the conduit got damaged, that's where I would be looking.

 

[ITO]

Naaaa just keep resetting that breaker, you will clear it eventually...

 

[DLTravis]

Naaaa just keep resetting that breaker, you will clear it eventually...

Clear what? The contactor as he goes flying across the room? This sounds like a good job for a megger...

 

[ITO]

The thing I like about fused disconnects is that if a fuse is blown the electrician is more likely to find the fault than to risk blowing a bunch of fuses trying to clear it.

A few years ago I did a job were the closeout required video taped training for the owner. While doing this training my electrician and the mechanical contractor got into a pissing contest over whether his VFD was faulty or our breaker was set wrong. To settle the argument my electrician repeatedly reset the breaker until the fault cleared and the mechanical contractor?s $40K VFD smoked. All caught on video tape by the GC in the presence of the owner. Everyone was quite impressed? of how incompetent my company was and they had the video tape to prove it.

To this day I give a speech about resetting breakers to all new hires and have fired more than a few electricians who try to clear faults by continually resetting breakers.

 

[220/221]

I'm assuming these are 480V fixtures?

Without a megger I would:

1. Disconnect all leads up the poles.
2. Energize coil closing contactor (to help prevent damage in case if short).
3. Turn on breaker and check phase to phase voltage and amperage.
4. Hook up poles one at a time checking amps as they warm up.

It will take some running back and forth but time is money.....right?

I wouldn't do any of the work hot @ 480 except testing.

And..........Exposed conduit pole to pole?????

 

[mxslick]

<snip>I reset it and 3 of the 5 came on (lets say A,B, and C). Then after a short time, they went off. I rest the breaker again and this time in the contactor box (nearby the panel) I heard a POP!

Guess what? Now you'll probably need to replace that contactor too. :roll:

Check it out carefully for burned/pitted contacts or evidence of a flashover. If you don't fix that you WILL be back soon to do it.

It can also explain why those lights still don't work, you may have completely vaporized that contact.

Eidted to add: If I read your post right, you were verifying voltage with a tick tracer? That is NOT going to give you a reliable reading..a tick tracer can detect "phantom" or leakage voltage, certainly not enough to verify that the lamps are getting power through a complete circuit. Use a wiggy.

 

[sparky723]

Lets clear some things up....

Lets clear some things up....

OK,... 1st of all.......

Naaaa just keep resetting that breaker, you will clear it eventually

Ito, I only reset the breaker twice. You act as if it was a sin to reset the breaker. That is what they are made to do.

To this day I give a speech about resetting breakers to all new hires and have fired more than a few electricians who try to clear faults by continually resetting breakers.

Ito, what are you talking about? I wasn't "trying to clear a fault".

I'm assuming these are 480V fixtures?

Yes, These are single phase, 480V.

And..........Exposed conduit pole to pole?????

Yes, running from the base of the poles to an LB down into the ground to the next pole. (Instead of running them in ground up into the tube so that they'll be in the pole.)

It can also explain why those lights still don't work, you may have completely vaporized that contact.

Contact is fine.

Eidted to add: If I read your post right, you were verifying voltage with a tick tracer? That is NOT going to give you a reliable reading..a tick tracer can detect "phantom" or leakage voltage, certainly not enough to verify that the lamps are getting power through a complete circuit. Use a wiggy.

I only used the tick to check for any signs of voltage. Had a actual tester with me.

I appreciate all the help that everyome gives. Thanks.

BTW, One of the legs had a short in it. Original EC had pulled spares. Used them and all went well. Lights are back on now. Thanks again, sparky 723

 

[jm1470]

Most of my business is parking lot light maint. you need to install fuseholders and fuses at the base of the pole. What sounds like what is happening is that you might have a couple of ballasts going bad and shorting to ground and tripping the breaker. This does happen a bad ballast can tripped a breaker or burn out a contactor. By installing a fuseholders and fuses you will prevent this from happening

 

[DLTravis]

Yes, These are single phase, 480V.

Everythings bigger in Texas

 

[sii]

SIDENOTE: the externally ran conduit from pole C to poles D and E had been previous hit by tractor or something, leading to the shorting of the wires and me having to re-wire this section of the wiring to poles D and E.

Sorry, this reminds me of something I had forgotten about. When I was in high school my parents divorced and my mom moved to an apartment in a very small town. Every once in awhile, the lights would go dim, TV would turn off, other random things. Every time, my mom would call the landlord who would in turn call an electrician who never found anything and has since retired. One of the other tenants finally got mad and called a "big-city" electrician (her words, not mine). He found the problem on the first call...the local city maintenance guy had hit the conduit on the corner power pole with the snow plow and one leg would occasionally go to ground.

Funny part is...this went on for 12 years!!! Wanna bet the first guy got a service call charge every time he came out?

 

[George Stolz]

Ito, I only reset the breaker twice. You act as if it was a sin to reset the breaker. That is what they are made to do.

Don't close your mind to new ideas - a circuit breaker is a lousy instrument to test for faults. Look at this from a different perspective: you know the breaker did it's job - or there is at least a 85% probability that it is performing correctly. So before you doubt it and re-energize the circuit, lock it out and test the load to see why the breaker did it's job.

There are many reasons.
One, if there was a problem when the breaker tripped, then it could still be there, ready to be found by a simple ohmmeter. If you energize the circuit and blow open the fault, then you've lost a lead.
Two, you can damage the conductors and start a fire if the breaker fails.
Three, there's the possibility that when you close that breaker into a fault you could damage the breaker.
Four, you could damage the contactor.

Ito, what are you talking about? I wasn't "trying to clear a fault".

That might not be what you thought you were doing, but your actions indicate you were - you re-energized the circuit twice before figuring out what the problem was.

I'm not saying I haven't done the same thing - but I appreciate the kind folks around here that showed me the error of doing it that way. Work smarter.

Yes, These are single phase, 480V.

Everythings bigger in Texas

I assume he is stating that it was a two pole 480v load.