Parking lot lights

Status
Not open for further replies.
S

starz

New member
This is a great forum and I want to thank all the electricians and engineers for volunteering their time to help other people. I have been recently called to a job where a 3 phase 20 amp breaker feeding 15 parking lights trips intermittently. The lights operate at 208 volts and are run in # 8 looped pole to pole. It is not in the budget to fuse everypole. I have changed the circut breaker for peace of mind and verified it is not overloaded This job has given me an excuse to finally buy a megger. Could anyone give some advice on how to megger the wires out properly and also some other troubleshooting tips that I might have overlooked? Any advice would greatly be appreciated. Thankyou, happy holidays and a safe new year to everyone.
 
The easiest first step would be to take all three hots off the breaker, and megger each phase conductor to ground. If you get bad readings phase to ground (and I very much suspect you will), go out to the pole and determine the wiring scheme if you can (layout). Disconnect the circuit at the halfway point out in the lot, and megger the bad phases to ground again. Keep halving the circuit until you've isolated the bad underground section or pole with the fault. Repair as necessary. For your purposes, I'd consider anything under 20 megohm at 500V to be faulty.

If you get good readings phase to ground on all three phases, then the test procedure gets a bit more complicated and labor intensive.
 
Could be many things.

If the wires are bugged in the poles with split bolts it could be a loss connection on one of them.

Water in the base of the poll

Bulb/ballast on top of the lights bad, wet, etc...

Problem in underground feed

I'd check each connection in the lights. I'd then systematically disconnect the lights from the center of the loop. Take amprobe readings or megga from there. See if when you hook up the second half you have simliliar readings or if one or the other sets the breaker off. If it does you can systematically narrow down the problem that way.

Just a suggestion or two.
 
I find it hard to believe that inline fuses would throw a job off budget.Time saved here should easily pay for it and not put all 15 down for a bad ballast.Wish you luck and welcome to the forum
 
You gotta find a way to get fuses in those fixtures. Let the owner know the risk of exposing people to his faulty wiring. I dont know about the rest of the world but we are required to fuse our ballasts here in Miami.
As far as troublshooting. I would check the site out for any recent underground work, visually inspect the fixtures from the ground, find out which ballasts were changed last and then begin halfing the circuits.
Of course megging the halfed circuits is a must.
 
Parking lot lights

jrannis said:
You gotta find a way to get fuses in those fixtures. Let the owner know the risk of exposing people to his faulty wiring.
Click to expand...


I agree about the need for fuses. I have seen utility co. installed street lights, at a sub-division wired directly to the transformer secondary,with no fuse protection, or egc. The poles were bonded to ground rods.

I complained to the utility about it, the best I was able to get them to do was bond the poles to the neutral, as per their specs.
 
Last edited by a moderator:
jrannis said:
I dont know about the rest of the world but we are required to fuse our ballasts here in Miami.
Click to expand...
I've never fused a pole light, the circuit conductors are protected by the branch circuit OCPD at the panelboard.
 
It appears to be working on Starz' end. :)

An overload is an overload, is it not? How is distance hurting us in this case?

About the only reason I can see for the individual fusing is that in the event of a bad ballast shorting or ground-faulting, then only that pole will be taken out, hopefully. The lot stays brighter, and people can see.

How are the circuit conductors safer?
 
georgestolz said:
It appears to be working on Starz' end. :)

An overload is an overload, is it not? How is distance hurting us in this case?

About the only reason I can see for the individual fusing is that in the event of a bad ballast shorting or ground-faulting, then only that pole will be taken out, hopefully. The lot stays brighter, and people can see.

How are the circuit conductors safer?
Click to expand...

The initial design would be more related to the over current. A short circuit would not have much of a chance to trip the OCP at that distance.

Keeping the lights on is what its all about
 
I agree with Marc as to the Meggering of the circuit, just be aware that the conductors need to be disconnected from the fixtures when proceding with the testing. Also, there are times when you will see the megger "trending", whether it is trending in the upward or downward reading. Pay attention to that, if it is occuring.



Jim W in Tampa said:
I find it hard to believe that inline fuses would throw a job off budget.Time saved here should easily pay for it and not put all 15 down for a bad ballast.Wish you luck and welcome to the forum
Click to expand...

I also agree with what Jim is saying here. Inline fuses at the poles is almost negligent in cost as compared to trouble shooting later for the cause of the lighting going out.
Also, some jurisdictions (and/or management companies) do not permit the parking lot lighting to be out, it is a large liability for them.
 
Pierre C Belarge said:
I agree with Marc as to the Meggering of the circuit, just be aware that the conductors need to be disconnected from the fixtures when proceding with the testing. Also, there are times when you will see the megger "trending", whether it is trending in the upward or downward reading. Pay attention to that, if it is occuring.
Click to expand...
No, no, no no no... I was giving the phase to ground test, and you absolutely want the fixtures to remain connected in that case. Most failing ballasts that are becoming intermittent will show up with a phase to ground test, which is why I suspect a phase to ground issue and not phase to phase. I didn't give any information on phase to phase, but that's when you'd want to disconnect the luminaries.
 
Just explain to the customer that every time a ballast goes bad you will have to go thru the same procedure to fix the problem what is it costing them for this troubleshooting? Verse 30 bucks a pole max and next time you will know wich ballast is bad next time.
 
eheins said:
Just explain to the customer that every time a ballast goes bad you will have to go thru the same procedure to fix the problem what is it costing them for this troubleshooting? Verse 30 bucks a pole max and next time you will know wich ballast is bad next time.
Click to expand...
Until the breaker starts to trip due to a bad underground piece, then that 3 or 4 grand they spent on pole fuses was for naught. Hey, I'm all in favor of the try at the upsell, but it might not pan out in the end.

By the way, I'm not so sure I could put fuses in a pole base for 30 bucks a go.
 
georgestolz said:
It appears to be working on Starz' end. :)

An overload is an overload, is it not? How is distance hurting us in this case?

About the only reason I can see for the individual fusing is that in the event of a bad ballast shorting or ground-faulting, then only that pole will be taken out, hopefully. The lot stays brighter, and people can see.
How are the circuit conductors safer?
Click to expand...

Depending on wire size voltage and length a dead short might never kick that breaker.Resisrance adds up and just might look like a load rather than a short.
 
mdshunk said:
By the way, I'm not so sure I could put fuses in a pole base for 30 bucks a go.
Click to expand...

The fuse holder and fuse alone cost more than $30. It's been a while since I've installed them but I know the fuse holders are pretty pricey.
 
jrannis said:
I dont know about the rest of the world but we are required to fuse our ballasts here in Miami.
Click to expand...

This is news to me. Required by specs? Certainly not any AHJ I've worked under.
 
I know that some of the DOT roadway lighting often specs those breakaway thingamajigs that look sorta like fuseholders. They're for if a car runs down the pole, the conductors will unplug and not have ragged live ends for the public to be exposed to. I think that fitting has a name, but it eludes me at the moment.
 
Status
Not open for further replies.
Top