ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Square D "All-In-One" Panelboard
by NORCAL - 11/30/21 12:48 PM
Where is Everyone?
by luckyshadow - 11/21/21 10:14 AM
It's been an interesting career
by The Watt Doctor - 11/19/21 09:56 AM
Well I am back to stay (nearly 6 years)
by The Watt Doctor - 11/19/21 09:17 AM
Motor Load Relationships Between Fans and Pumps
by The Watt Doctor - 11/18/21 09:24 AM
New in the Gallery:
240/208 to a house
240/208 to a house
by wa2ise, October 9
Now you know.
Now you know.
by Tom_Horne, September 7
Who's Online Now
0 members (), 58 guests, and 22 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 2 of 3 1 2 3
Joined: Jul 2007
Posts: 1,335
S
Member
RDK, Based on what you have told us thus far, Here is what I suggest. First, fix what has burned up and disconnect the light circuit(s) in questioned. Varify that power and system is kosher. The burnt equipment could be the source of the problem.

Once that is all done. Varify you have the proper voltage on each leg going out to the lights.

Then ask yourself, "If I was going to run the conduits for the lights, how will I do it?" This can give you a starting point where to start looking. Once you can confirm conduits and wire routing, document it as an as-built. Check the connections. At each piece of equipment, check to see each light is rated for the voltage and that you have the correct voltage at each light. Document your findings.

I suggest if you feel comfortable doing this is if possible, locate a junction in the wiring that is in the middle of the circuit. De-energize the circuit(s), properly open the circuit(s) after properly marking them and protect all exposed ends. Energize the circuits. This will tell you several things. Whatever is energized and de-energized will tell you what side of the opening in the circuit(s) each load is on. If the goofy voltage dissappears, the problem is on the de-energized portion of the lighting system. If the voltage is still goofy, the problem is on the energized portion. Keep on repeating this until the problem is found. It may not be easy but highly effective. The theory here is you can have a ciruit with 1 million good splices and 1 bad splice. You can find that bad splice within 20 guesses by using this process. Keep in the back of your mind that there can be multiple problems and they can be on both sides in the open circuit so do not get tunnel vision. Also do not let burnt out bulbs trip you up.

When tracing circuits and conduits, do not be suprised to come to a relization that there is a junction some where like a hand box or junction box that you are not aware of. Keep us posted. I like these type of problematic issues. I know, I'm a sick individual. sick


"Live Awesome!" - Kevin Carosa
Joined: Apr 2007
Posts: 33
R
RDK Offline OP
Member
The bad thing is ive done this all with no luck. PLus the whole building is mostly lumex.Ive started at the middle and worked from there. Seems like the problem is before the first light on all four circuit(s). The Burnt lights are on another set of breakers in the shop. The pots are in the office side from a diffrent pannel.

Joined: Feb 2004
Posts: 1,438
Member
This almost sounds like you have 2 different systems crossed... Do you have 480Y/277V in the building at all? I'm not sure how you can get 255V otherwise, especially if all is well in the panel (aside from being stablok whistle ) Even if this were a high leg system, you'd at best have around 2o8V-G. If no ballasts are involved and your panel voltage is 208V phase to phase, you're picking up voltage from a source outside of that panel to get 255V.

Joined: Apr 2007
Posts: 33
R
RDK Offline OP
Member
Thats what im thinking. With no prints or as builts im sorta lost. No 480/277 check all pannels.

Joined: Nov 2007
Posts: 763
K
Member
Can you find which circuit breakers in which panel are feeding these lighting circuits?
I would recommend investing in a circuit tracer and toner/tracer set if you don’t already own one. Especially since this building sounds like it’s going to be "your baby" from now on. They can sometimes make problems like this a lot easier to tackle.

Since we are shooting in the dark anyway, is it possible these lights are hooked up to an autotransformer dimmer or something that could be incorrectly wired and somehow acting like a boost transformer?
If you are sure it’s a 208V supply, even with a bad neutral connection, I can’t see how there can be 255V anywhere in the building without some type of transformer ahead of it. I just noticed that you’re in Canada though and I’m really not at all familiar with the type of materials and wiring practice used there .



Joined: Dec 2000
Posts: 4,288
Member
A bad neutral couldn't get 255V from a 120/208V system. At most it could be 208V
As a matter of fact, the situation you're describing is impossible electrically without some other influence.

255 Volts is a reading typical of a metal halide ballast's open circuit voltage.
Have you taken a mirror and a flashlight and looked through the hole for a ballast possibly mounted remotely? Some of them can be a real nightmare and take a real long arm to replace.
Taken a L-N voltage reading at the fixture's junction box line terminals instead of the lampholder? With a solenoid type tester?


Joined: Mar 2007
Posts: 49
A
Member
I have to second electures above comments and those of Lostazhell, even with an delta service (or open delta) "high leg" there would be no way to get 255 volts as line voltage, an open neutral does not explain it.

There has to be a ballast/transformer/step-up influence of some kind at work here. The four that work are normal incandescent par 38 lamps? What is the voltage at thier lamp socket? what do the fixture nameplates if any say? I need more info to attempt a diagnoses but find the 255 volt report revealing in that there simply has to be a step-up process of some type involved. Let us know what you find....

Joined: Aug 2002
Posts: 402
J
Member
In Canada it is common to use 347 volt for lighting which comes from the 600 volt three phase.

Joined: Jul 2007
Posts: 1,335
S
Member
Now that I think of it, you are right about the open neutral The floating voltage will not exceed the phase to phase voltage. blush

The problem about trouble shooting on a message board is like a doctor treating a patient over the phone. You get tunnel vision.


"Live Awesome!" - Kevin Carosa
Joined: Jul 2007
Posts: 265
W
Member
I agree I did not see the part about the 208v supply the first time I read the post, tunnel vision I guess


Jimmy

Life is tough, Life is tougher when you are stupid
Page 2 of 3 1 2 3

Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
electure
electure
Fullerton, CA USA
Posts: 4,288
Joined: December 2000
Top Posters(30 Days)
Admin 3
dsk 2
Popular Topics(Views)
286,302 Are you busy
218,753 Re: Forum
204,906 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5