# Mysterious power problem



## vikkaraja (Oct 1, 2009)

Hello, I have a very strange problem with my exterior lightings. I have 3 separate CB feeding a Contractor for total of 12 high pressure sodium lights. all lights are fed with 120VAC each. Whenever lighting circuit calls for contractor to energize and turn lights on. It kills most of my wall outlets. One time it actually burnt some power strips.I checked voltage on contractors reference to ground once contactors were closed.It read as follow CB 61V, CB 234V, and CB 11V.
Here is what I checked so far: loose neutral, any crossed neutral wires from 480/277 to 208/120 panel boards, checked transformer wirings connections 3 phase 480 Delta to 208/120 Wye.

Any help will be very appreciated.
Thx


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## Black Dog (Oct 16, 2011)

vikkaraja said:


> Hello, I have a very strange problem with my exterior lightings. I have 3 separate CB feeding a Contractor for total of 12 high pressure sodium lights. all lights are fed with 120VAC each. Whenever lighting circuit calls for contractor to energize and turn lights on. It kills most of my wall outlets. One time it actually burnt some power strips.I checked voltage on contractors reference to ground once contactors were closed.It read as follow CB 61V, CB 234V, and CB 11V.
> Here is what I checked so far: loose neutral, any crossed neutral wires from 480/277 to 208/120 panel boards, checked transformer wirings connections 3 phase 480 Delta to 208/120 Wye.
> 
> Any help will be very appreciated.
> Thx



Why not make the HPS lights 277 volts and feed the coil at 277 volts as well.

Of course change the coil to a 277 volt coil.

This will separate the 120/208 volt crap from the lights.


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## vikkaraja (Oct 1, 2009)

Thanks for your quick response. These lights had been working for a long time and now all of sudden I have this problem.
By am i Reading these strange voltages?


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## Black Dog (Oct 16, 2011)

vikkaraja said:


> Thanks for your quick response. These lights had been working for a long time and now all of sudden I have this problem.
> By am i Reading these strange voltages?


All it takes is one ballast and all hell will brake loose.

It may be a bad ballast that is causing this,,..


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## A Little Short (Nov 11, 2010)

vikkaraja said:


> Hello, I have a very strange problem with my exterior lightings. I have 3 separate CB feeding a Contractor for total of 12 high pressure sodium lights. all lights are fed with 120VAC each. Whenever lighting circuit calls for contractor to energize and turn lights on. It kills most of my wall outlets. One time it actually burnt some power strips.I checked voltage on contractors reference to ground once contactors were closed.It read as follow CB 61V, CB 234V, and CB 11V.
> Here is what I checked so far: loose neutral, any crossed neutral wires from 480/277 to 208/120 panel boards, checked transformer wirings connections 3 phase 480 Delta to 208/120 Wye.
> 
> Any help will be very appreciated.
> Thx


What is the line side voltage on the contactors? Did you measure each one to neutral?
Sounds like you have lost the neutral somewhere. Since you say you have 3 circuits and all are affected, you are either using a MWBC with a single neutral that is open, or you lost the neutral at the main or sub panel if using one.


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## Walkman (Aug 16, 2014)

Get an electrician out there who knows how to troubleshoot and locate the failing (failed) neutral.


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## glen1971 (Oct 10, 2012)

vikkaraja said:


> Hello, I have a very strange problem with my exterior lightings. I have 3 separate CB feeding a Contractor for total of 12 high pressure sodium lights.


Found your problem... You are energizing a "contractor" and not a "contactor"...


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## vikkaraja (Oct 1, 2009)

Line side is 120 in reference to neutral. Yes all 3 Circuit Breakers have same neutral. And it surely is not loose anywhere in the panel. I checked and double checked myself.


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## vikkaraja (Oct 1, 2009)

glen1971 said:


> Found your problem... You are energizing a "contractor" and not a "contactor"...


Damn auto correct.

Thx


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## A Little Short (Nov 11, 2010)

vikkaraja said:


> Line side is 120 in reference to neutral. Yes all 3 Circuit Breakers have same neutral. And it surely is not loose anywhere in the panel. I checked and double checked myself.


May not be loose in the panel but it is open somewhere given your readings. You need to check continuity all along the neutral path. Check between points to isolate where it might be compromised.


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## ponyboy (Nov 18, 2012)

Your neutral could be almost completely compromised by the sound of it and the lights are still finding a way to work. I'd say you might have a potentially bigger problem than you think


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## A Little Short (Nov 11, 2010)

ponyboy said:


> Your neutral could be almost completely compromised by the sound of it and the lights are still finding a way to work. I'd say you might have a potentially bigger problem than you think


I'd say the ballast on those lights are multitap and are working on whatever voltage they're getting. But they will fail soon. Since it's a MWBC they're getting a backfeed/return from the other lines.

To the OP:
GET THAT NEUTRAL FIXED!
Or you'll fry more than a power strip!:whistling2:


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## vikkaraja (Oct 1, 2009)

Thank you all for your help. I am returning back to work tomorrow to continuing investigate further with everyone's suggestion. This building is 24K square feet.


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## Big John (May 23, 2010)

vikkaraja said:


> ...Yes all 3 Circuit Breakers have same neutral. And it surely is not loose anywhere in the panel....


 "Tight" only means good when you're bragging about your girlfriend. Just because an electrical connection is tight definitely does not mean it's good.

So you either haven't found the loose conductor or else the one of the tight connections is still bad. Either way you definitely have an open neutral.


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## ponyboy (Nov 18, 2012)

vikkaraja said:


> This building is 24K square feet.


Good, then you should be able to find it lickity split


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## btharmy (Jan 17, 2009)

If it is affecting both lighting and receptacles, I would start at the service.


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## eddy current (Feb 28, 2009)

You have 3 light circuits. Disconnect 2 of them and only energize one at a time. This will narrow down which circuit has the bad ballast or loose connection. 

Then try and find the approximate middle of that circuit and open it only energizing half of it.


Process of elimination. You'll find it


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## don_resqcapt19 (Jul 18, 2010)

btharmy said:


> If it is affecting both lighting and receptacles, I would start at the service.


Sounds like the service is 480 and the problem is on 120 volt circuits. He needs to start at the secondary of the 480-208Y/120 transformer.


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## A Little Short (Nov 11, 2010)

don_resqcapt19 said:


> Sounds like the service is 480 and the problem is on 120 volt circuits. He needs to start at the secondary of the 480-208Y/120 transformer.


What would be the symptoms should the X0 connection be lost or really loose?


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## vikkaraja (Oct 1, 2009)

Good news to report. It's all good now.
There was one loose neutral connection for one circuit and for other 2 there was a neutral but from a totally different panel.
I ran a new white neutral wire from the same panel where circuits originated.

Thanks guys and enjoy your weekend!


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## shwadaddy76 (Apr 28, 2013)

Have you verified that the coil is energizing with the correct voltage? If this happens when the coil is energized, it could be an issue related to the coil. If not, and you have 3 ccts connected to contactor, I would isolate (1) circuit at a time, and try to find which one has the issue.


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## Walkman (Aug 16, 2014)

Good job! Sometimes those can be pretty elusive when troubleshooting.


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