Light Fixture Wiring Problem


  #1  
Old 12-11-20, 10:14 AM
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Light Fixture Wiring Problem

Hi Everyone.

I desperately need some help on this electrical issue i'm having, which was just basically replacing a light fixture from an LED one to a regular lightbulb.

An LED fixture in my bathroom stopped working for some reason, so i thought it was the LED itself and figured i'd just get a new lightbulb fixture. In the first picture, the white wire on the left went to the white wire on the LED fixture, black wire to black wire, and I believe ground to ground. I didn't find the tied together black and white on the right until later. I hooked up the new fixture with the same wires and for some reason isn't working either.

I tested both the bulb and the new fixture. The bulb works fine in another fixture, and the wires out of fixture have continuity to the right points in the bulb socket
I also tested the switch in the second picture that the fixture is connected to because i thought that was the problem, but that passes a continuity test when switched on.

I tried checking for AC voltage with a meter on the switch AND all the wires in the fixture and am getting absolutely nothing, with the switch on or off. So i went and bought a Contactless AC Voltage detector and it goes off when you put it near the switch AND the outlet.
I'm not even sure how this is wired anymore, or what that extra pair on the right even does. And i'm not sure what else these wires go to, but this is the only spot having issues on this floor.

I turned off the breaker for the entire 2nd floor where this is at and all power turned off, even to this switch and fixture. Checked it with the Contactless detector and nothing. So i know that it's on the same breaker as everything else on the floor.

I've figured all this out and i'm completely confused. Does anybody possibly know what's going on here?




 

Last edited by PJmax; 12-11-20 at 11:02 AM. Reason: resized pics
  #2  
Old 12-11-20, 10:29 AM
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You have what's called a switch loop.

The power comes in one of the cables into the box.
The other cable goes down to the switch.

Since the black-white are connected together at the ceiling box, that means the cable closest to us (in the pic) is the main power coming in. The power then goes via white to the switch, and back via black.

You should be able to easily connect the fixture to the two wires you have disconnected now, black and white and it should work as expected. The grounds should all be connected and wire-nutted together too.

If it's still not working, I'd check the breaker, maybe something tripped as you were working on it
 
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Old 12-11-20, 10:47 AM
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Hi, one other thing, the wires are going around the terminal screws the wrong direction, but that’s not causing your problem.
Did you break any of the splice?
Geo 🇺🇸
 
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Old 12-11-20, 10:58 AM
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Since using a non contact tester is showing power...... you have hot power but have lost the white/neutral. You will need to locate where that light gets its power from. Possibly check in the attic.
 
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Old 12-11-20, 11:11 AM
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Zorfdt The breaker seems to be fine, as well as the rest of the upstairs which is on that breaker.
And yeah, i connected up the new fixture just like the old one and for some reason wasn't lighting up.

Geochurchi Wasn't aware of the wires being in the wrong direction. I'm assuming you're talking about the switch right? Also, you mean the splice of the black and white on the right in the first picture? Then yes i did break that already to do testing.

PJmax I had a feeling i'd have to check further up the circuit for it, which the lines should come up through the attic i believe. Now that i have a better grasp of what each bundle/line and wire is doing, it makes this a lot easier.
 
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Old 12-11-20, 12:04 PM
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Holy Jesus. I just put everything back together to try it again and while i was moving it around, it came back on a few times in split seconds.

I double checked the wire nuts around all the connections and everything seems firm. The lightbulb popped on a few times while i was trying to turn the nuts around and visually inspect the inside of them in the air.

Not sure how this happened yet.
 
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Old 12-11-20, 07:08 PM
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I'd first check the one wire nut that you see to be sure it's secure.

Secondly, how old is your house? Sometimes old houses have hidden junctions just behind the box (of course against code and safety). But if the house is less than 50-75 years old, that wouldn't be my first guess.
 
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Old 12-11-20, 08:04 PM
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Zorfdt It was built in the 1920's sometime, but the electric was updated around the 1970s or so (I think?).
But at this point, i do think it's a junction box up in the attic as well with a loose connection maybe.
Hot wire coming in seems fine, switch seems fine, and the fixture works fine. The return neutral is the last thing.
It's full of insulation on the floor up there that i'm not sure if is covering up a possible junction box or not.
 
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Old 12-11-20, 08:26 PM
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Probably not the source of the issue but the switch is wired wrong. The wires are not under the screws all of the way and are wrapped the wrong way they should be around the screw the same way (clockwise) the screw tightens as it draws the conductor under not away from the screw. Looks like a switch loop to see if the switch is the issue take a wire nut and connect the black and white wire together. The black and white should only be together in a switch loop never any time else or that is a direct short and should trip a breaker of blow a fuse.
 
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Old 12-12-20, 06:31 AM
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You had a black wire and a white wire connected together. While you are at it you could take off that wire nut, check to see that the bare wire ars are firmly twisted, and put back the wire nut. Do not connect a black to a white that you did not see connected to each other previously because the chances are very high that you will make a short circuit that throws off a frightening spark that in turn could make you fall off of a ladder or stool.

You said that the light flashed on and off while you were holding it in your hand. There is a loose connection somewhere possibly a broken wire within the plastic insulation.
 
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Old 12-14-20, 08:26 PM
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Yeah, so it was definitely the neutral at the junction box.
Looks like it wasn't even hooked around the neutral bundle right and came undone somehow.
There was electrical tape in the first picture, barely, but i took it off for the second picture.
They're connected together a lot better now and the receptacle finally has power.



 
 

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