Light fixture stopped working


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Old 11-18-19, 08:19 AM
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Light fixture stopped working

I have two separate two bulb light fixtures in my bathroom, both on different switches and one of them just stopped working yesterday. I replaced the bulbs, still didn't work. I pulled the switch and with a non-contact tester I have power on the black wire coming from the breaker. When the switch is on there is power on the black going to the fixture, but lights still not working. I pulled the fixture to check wiring and all looked good. Again I turned on the switch to see if there was power to the black on the fixture. At the fixture my non-contact tester shows power on black, white, ground and on the metal fixture itself, what the heck?! If somehow the power is going through the black to the neutral/ground, wouldn't the breaker be tripped? My bathroom ceiling is just below my attic space and I have heard squirrels up there lately. Maybe they chewed up the wire going to the fixture and black is exposed to neutral or ground now? The squirrels chewed up electrical in my barn where black was shorting on neutral but the breaker was tripped each time I turned on the lights. Any other thoughts on this? I'll check the attic tonight for a chewed up wire. Thanks!
 
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Old 11-18-19, 09:37 AM
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You have to check the voltages with a meter.

Non contact tester is too sensitive. So if there is even a couple volts ghost voltage on a wire it will show that it has power.
 
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Old 11-18-19, 10:09 AM
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Non-contact ones are notorious for giving false readings. Get a traditional multimeter. Inexpensive analog testers with a needle work great but a digital will work as well.

 
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Old 11-18-19, 10:39 AM
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Thanks, I have a multimeter I'll try that before going into the attic. What should I be checking for voltage wise? 120 volt at the fixture? Also what setting should I turn the dial to for 120 volt?
 
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Old 11-18-19, 11:21 AM
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You will be testing for AC voltage. If you have an analog meter (with a needle that moves) set it to AC and pick a voltage number higher than 120. In my photo that would be red ACV 250. On the meter in the photo the needle will come up to about half way when 120 VAC is present. Don't worry about reading what it indicates exactly. If it's something in that area it's telling you that you've found 120 VAC.

This is why an old fashioned analog meter is good. All you're looking for is the needle to rise to "something". Digital meters are so sensitive their display is often a bunch of numbers jumping around. You have to be careful to read the scale it's on or look for the decimal point.

If you have a digital meter set it to AC. When you touch the probes to the wires you want the display to be somewhat stable and it should be a number close to 120. It might be 118.5 or 120.7 but it should be pretty stable and the numbers shouldn't be jumping all over the place.

On this meter set the dial to the V with the wavy line over it.
 
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Old 11-18-19, 02:56 PM
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The black wires at the switch are showing 123.9 v when the switch is on. When I test the black on the fixture and using the fixture ground or neutral wires I get 0. When I test the black at the fixture using a ground at the switch I get 123.9. So it seems like the neutral and ground are no longer intact. Also, I noticed the sheathing on the switch going to the light is white, and the sheathing at the fixture is yellow. So there must be a junction box somewhere? I recently purchased this house and Iíve noticed a lot of weird things done!
 
 

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