Help! Advice needed in wiring ceiling light fixture.


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Old 07-14-17, 06:42 PM
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Help! Advice needed in wiring ceiling light fixture.

I bought a HUD home that had sat empty for over two years and had been severely vandalized. One of the many things that had been stolen were the light fixtures. I've successfully replaced all of them on my own, with the exception of one that's giving me fits.

The ceiling junction box has two sets of wires hanging from it; two black, two white, and a green. Both black test hot, as does the actual light switch. The fixture I'm attempting to install has two bulbs, and as such, also has two sets of wires: two black, two white, and a copper grounding wire.

Here's the rub... When I attach all blacks to blacks, whites to whites, and copper to green, the light turns on, but the switch on the wall won't control it. There's no turning it off unless from the fuse box.

What am I missing? I know I'm probably describing the issue inadequately, so please feel free to ask for any additional information you may need.

Thank you!
 
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Old 07-14-17, 06:48 PM
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You have only described half the circuit. Tell us about the other half of the circuit. Do you have black and black on the switch or do you have black and white on the switch.
 
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Old 07-14-17, 07:45 PM
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It's black and white at the switch.
 
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Old 07-14-17, 07:50 PM
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You have a switch loop.

One cable supplies the feed or hot to the box and the other is the switch cable.
You need to determine which white/black pair is the power.

The circuit then gets wired like the diagram.

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Old 07-14-17, 08:15 PM
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You must Identify which cable is hot and which goes to the switch. (A non contact tester can't be used.) If you have a multimeter check black to white of each cable. If no multimeter choose one cable and connect the light. If the light works that is the hot and the other cable is your switch cable.

Note the white of the switch cable must by code be remarked black (or any color but gray or green) on both ends. A couple of bands of black electrical tape is a good way to mark it.
 
 

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