2 Circuits Controling A Light

TNRocks

I have enjoy this forum. Read it everday to better understand how things work or should be done. But here's a situation that I came across today at a friends house. He was checking his circuit breakers to see which one control what. He tells me that his stairway light wont go off. He's tried all the breakers but nothing. The light is on a 3 way switch. I ask him to go thru the process again and sure enough the light never shut off. I ask him to throw the main and light went out. So we knew it was wired to somewhere in the house. I then had him turn each breaker off and leave it off. Sure enough half way thru the breakers in the off position and leaving them there the light went off. To make the story short it took 2 breakers (1 on either side of the panel but not opposit each other, one was in #2 position and the other was in #5 position) in the off position to make the light go off. If either breaker was in the off position the light would stay on. My question is " Is this a safe way to have the light wired". Secondly how would u wire a light like this, to use 2 breakers?

220/221

I've seen it before.

It may have been fed from two locations from day one or someone could have backfed it during some rework. They are both on the same phase so it never showed itself.

There is no easy answer.

You have to take it all apart and find out what goes where.

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Just because it's within code doesn't make it safe.

Just because it's against code doesn't make it unsafe.

mdshunk

If you leave any one of those two breakers off, does everything in the house work? There might just be two feeds for the same circuit, mistakenly.

Magnettica

Common problem.

Two different circuits on the same phase/ leg/ arm, whatever you want to call it.

Speaking of same phases... anyone ever wire a motion light with a 3-wire so that when the light switch is off, the light is controlled by the sensor, and when the switch is on the same light is controlled by the switch?

It's a fancy set up.

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goose134

Actually, I was going to do that very thing (little different). I got a three pole contactor at work and was going to use a three-wire as a photo cell by-pass for the coil. One position engages the photo sensor, the other turns on the coil. Overkill? Maybe.