Red, White, Black. What to use?


Old 01-06-16, 04:45 AM
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Red, White, Black. What to use?

I live in Southern Arizona in a home built in 1983. The majority of the wiring is Red, white and black, with a ground.

I removed (and capped in a junction box) some wiring to security lights after we moved in to install solar LED security lights. Long story short, I have a need to install a dusk to dawn security light to cut down on pack rats.

I took a voltmeter to the wiring and here is what I found.

Red and White = 120 volts
Red and black = +/- 10 volts

I don't remember what the black and white read as.

I got new wiring and paired the new black to the old red and the new white to the old white. I used a wire nut on the old black and was getting 120 volts at the new black and white.

Is that the correct procedure? Or should I have bundled the old black with the old white to the new white?

This whole red, black and white is a bit confusing.
Old 01-06-16, 05:09 AM
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I don't remember what the black and white read as.
That is important for us to know. But then you said you were getting 120 v at the black and white. Often reds are switch controlled. Is there a switch in the mix? If you are getting 120 v from red to white, use them and cap off the black.

White is neutral. Red, black and colors other than gray and green are current carrying conductors, or can be if not part of a switch loop.
Old 01-06-16, 05:19 AM
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The red can be a second hot, a switched hot or part of a switching arrangement. There is no hard and fast rule.
Old 01-06-16, 07:36 AM
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Your old security lights might have used a photocell in a separate wiring box. Look around the eaves of your house and see if there's a box with a photocell.

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