Wire colors mixed exterior porch light.


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Old 04-12-20, 01:56 PM
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Wire colors mixed exterior porch light.

I pulled a porch light off to replace it as it was looking pretty rough. There is a single switch that controls this light.

I was surprised to see two romex cables inside. But I was more surprised to see them not connected in a parallel fashion (forgive the use of a DC term.

The two black wires from the two romex cables are tied together.
One white from one romex is going to the white wire on the fixture.
The white from the other romex is connected to the black wire on the picture.

The bare copper are all connected together.

Any ideas what is going on here so I know where to look for issues if need be perhaps it is legit wiring. But it seems odd for household wiring.

I'm not an expert so I could be completely wrong.

 
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Old 04-12-20, 02:05 PM
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That's called a switch loop. Power is fed to the light on one cable. The second cable goes to the switch. The white of the switch line is hot to the switch and the black is switched hot back from the switch.

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Old 04-12-20, 03:59 PM
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PJmax thank you for the education. The switch is further from the power source than the light so this makes sense as it makes the wiring shorter overall.
 
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Old 04-13-20, 10:02 AM
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FYI, the white wire to the switch (in both the switch box and the fixture box) is supposed to be remarked as a hot wire. Usually with a piece of black electrical tape. Remarking the wire makes it clear to anyone who comes next that it's considered a hot wire and not actually a white/neutral.

As you've seen, it's a code requirement that's often forgotten about.
 
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Old 04-13-20, 08:55 PM
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Zorfdt thank you for that tidbit. I will look at it and mark it accordingly.
 
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Old 04-14-20, 05:41 AM
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Nitpicking. The wire connected to the black lead of the light fixture may not be white even if remarked with black tape. But for now, if you can get it to work without making this fix, then procrastinate on this fix until you figure out how to do this fix (requires more than passing Common Core school education or an SAT).

Hint: The black wire coming up from the switch should be the wire connected to the light fixture black lead.
 
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Old 04-20-20, 05:58 AM
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AllanJ That is what I went off when I market the white wire.

Installed the new lite, all is working as it did. I knew I could just rewire it the same is it came out, but wanted to first learn what I was seeing and second ensure things were not funky.

Thanks all.
 
 

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