Light fixture went dim


  #1  
Old 11-05-22, 01:11 PM
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Light fixture went dim

We are replacing landscape and hardscape. We have had some workers on site using power tools including a jackhammer. Last night, the light fixture on the pier on the right side of the photo was dim when turned on. It's at less than half brightness. The two fixtures hold identical LED bulbs and I swapped them to make sure the bulb was not at fault.

Even stranger, no incandescent bulb I have tried will illuminate at all in that fixture.

The fixtures are brand new, only a few weeks old. I pulled the fixture and checked the wire nuts were tight. Between the fixture and the house are a couple of junction boxes; one just below the light and another at the house. They appear intact.

What might have caused this and how can I fix it?

 
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Old 11-05-22, 01:54 PM
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The fact that the incandescent bulb does not light indicates that the LED is illuminating via “ghost” current. That usually occurs when a no-neutral switch or dimmer is in the circuit. I suspect in your case that the wiring is damaged, possibly a neutral to ground short.
 
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Old 11-05-22, 01:59 PM
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Are these line voltage (120 VAC) fixtures? Given the construction, I would suspect wiring damage somewhere although it's certainly possible the construction loosened up a connection somewhere. Your best bet is to get a voltmeter (a cheapie will do) and measure the voltage at the fixture (with the light on and bulb in place). You'll likely find it is low at the fixture. Then work backwards towards the house until you isolate the problem area.
 
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Old 11-05-22, 02:06 PM
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Workman should know better.
Jackhammers and impact tools require high power and need to get power near the panel.
I've repaired a lot of problems like yours.

I would doubt it's a major problem. More than likely it's an open neutral as 2john mentioned.
You'll need to check everything on that circuit. It will probably take a meter to find it.

Could be a corroded wirenut/splice.
Could be corroded terminals on a receptacle where the power comes in and goes back out.
 
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Old 11-05-22, 02:47 PM
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Thanks for the replies.

I had measured at the bulb socket, without the bulb in place, and got 118v. Taking my meter to an indoor receptacle showed 121v. Is that significant?

3 other lamps on the same switched circuit are operating normally, so I guess there is some wire damage between the house and that one lamp. With the yard dug up, I see wires not in conduit and they look pretty beat up, but I have no idea which wire goes where. I jiggled all the exposed wires I could find but the bulb didn't brighten.

I guess I'll need to find the wire and replace it. Difficult with it being buried and I don't know where the source end is.

My general contractor is a nice guy and pretty smart, do you think I have any hope of getting him or one of his minions to figure it out for me?
 
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Old 11-05-22, 05:33 PM
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118 vs 121 is normally not significant, but you measured it with no load on it (bulb was not in place). I'll bet if you measure it with the bulb in place it will be a lot lower. With a damaged wire or bad connection in the path, it often doesn't show up until you try to draw current through it (which is what happens when the bulb is in place).

I think you certainly have a case that the construction damaged the wiring somehow and that the contractor should be responsible for getting it fixed, whether he does it himself or calls in a sparky. If the contractor is reasonable they should take care of it. Best to do it now while stuff is torn up; it will only be harder to fix later.

It may be that when someone figures it out it may be a pre-existing problem that was just pushed over the edge by the work; in that case you might be on the hook for the repair.

PS: Beautiful house and yard!
 
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Old 11-18-22, 10:34 AM
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The wire supplying the fixture ended up cut in several places by the workers. The contractor took responsibility and had a pair of electricians come and fix it yesterday. All is well.
 
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