Blinking light troubleshooting 101

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JES2727

Senior Member
Location
NJ
Easiest way to determine if the dimmer is the culprit: Unscrew 4 or 5 of the lamps in the fixture to reduce the load on the dimmer and see if the flickering ceases.
 

dhalleron

Senior Member
Location
Louisville, KY
Thanks guys.

hurk27 mentioned he has seen them strobe when near the rated capacity of the dimmer. I never said they strobe in my post, but that is one word the customer used to describe it. It is a steady strobe when it does it.

The latest news is that it only happens at night. It seems to stop when other lights on that circuit are turned on. And she seems to think it only does it when her front porch screw in photo cell is on. This photo cell is way downstream of my problem light.

From everyone's input, I think now I need to go back and focus on the dimmer.

I'll be back with an update.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
This is not a good idea. How in the world are you going to justify getting a new PQ meter if you use such a simple procedure?!
Dang! I just screwed myself out of the opportunity to spend a lot of money! :mad:


Oh, well. :roll:


Now I need to go feel some wires so I can ruin the chance to but an IR imaging camera. :cool:
 

G._S._Ohm

Senior Member
Location
DC area
It seems to stop when other lights on that circuit are turned on.
Intermittent bad connection? If you don't have Ideal's 65-165 circuit tester you can test this circuit by putting a 10 A load on it, but with the tester or without you need to estimate the wire length back to the panel.
50' of #14 copper back to the panel should give you no more than a 2.5 v drop from the nominal 120 v.
 

dhalleron

Senior Member
Location
Louisville, KY
So the customer thinks she did her troubleshooting and fixed it.

So the customer thinks she did her troubleshooting and fixed it.

She said it only happens at night. That's why it never happened when I was there. She said she traced it to the front porch light. She had installed a screw in photo cell on that light back in the summer a few months before this problem came up. She unscrewed the photo cell and only controls the light by the switch. I haven’t had a call from her in over a week.

The front porch light is on the same circuit and is near the end of the circuit downstream of the problem light and downstream of other lights that work fine. She thinks she fixed it and I didn’t argue with her. What do I know?

She doesn't want me to come back unless it blinks again. I do have my new data logging meter that came in the mail last week. I'm itching to use it.
 
By multiwire circuit, you mean a shared neutral? I would check the loads on the other side of the shared neutral, to see if some heavy load combined with a loose neutral somewhere is causing a voltage shift in the neutral. Of course, the other side of the multiwire hot IS on the opposite side of the 240v.....?
 

dhalleron

Senior Member
Location
Louisville, KY
By multiwire circuit, you mean a shared neutral? I would check the loads on the other side of the shared neutral, to see if some heavy load combined with a loose neutral somewhere is causing a voltage shift in the neutral. Of course, the other side of the multiwire hot IS on the opposite side of the 240v.....?

I'm not going back unless her "fix" isn't really the fix.

Yes it is a shared neutral. I checked the panel. The multiwire circuit is on twin breakers but they are on different twin breakers on opposite phases.

There are no heavy loads on this multiwire. Only lighting in a residence. So, would a loose neutral downstream of my light affect the voltage at much my light? Maybe so. That?s why I bought my new data logging meter. If I go back, I?ll use it to see what the voltage is really doing when I am gone.

How could the photo cell affect it? I don?t know.
 
By multiwire circuit, I assume you mean a shared neutral. Is the other side of the circuit on the other side of the 240v panel?? I would check the voltage to ground of the neutral at the light box, to see if there is some other load on either side of this multiwire circuit that is shifting the neutral. See what loads are on both sides of this circuit and turn them off and on while checking the neutral and hot voltages at the light. Then look for the loose connection. Good luck! I found a circuit once that some idiot used the jacket of the bx as the neutral. :roll:
 
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