7 posts / 0 new
Last post
Help for a friend...

My friend lives in a 100 year old row home that has had several renovations by several different people.

His kitchen was redone a couple of years ago with new wiring and fixtures. He tells me everything was working fine until a couple of months ago. As far as he knows, nothing was changed. He has had other work done in the house but he says that is not when the problems began.

The problem is with two kitchen lights that operate on two separate switches (in one box) fed from the same circuit breaker. He says they used to operate independantly as expected but now turning on EITHER switch turns on BOTH lights. When you turn on either switch the other switch has no effect on either light. So basically either switch turns both on and both switches have to be off to turn both lights off.

I suspect one or both switches are bad and just need to be replaced but just in case here is more detail. I took off the switch plate and have tried to diagram what I saw (attached), but I did not remove the light covers so I'm only speculating how they are wired. The important point is that they WERE working properly (so he says - and I KNOW he would not mess with wiring).

The feed from the panel is 12/2 romex (B&W + ground) and coming into the switch box from the lights is 12/3 romex (B,W,R + ground). You will notice a bit of white on the red wire. The installer put a piece of white tape on it for reasons I can't figure unless that's how he was trying to mark it as hot. The switch screws are wrapped with white tape so maybe that's just what he used though I would think it should be black tape?

I didn't have any spare switches and it was late but do you think that's the first thing to try? Any other suggestions?

Re: Help for a friend...

If a switch is bad it is either always open or always closed which doesn't meet your scenario. I would suspect it is a problem at the light fixtures and that they are wired in series.

Vern Smith
Re: Help for a friend...

The lights are wired in parallel somehow. Switch wiring looks OK, so it's probably at the lights somewhere. You'll just have to open up each fixture and inspect the wiring. Somewhere, you'll find the red circuit and the black circuit hooked together.

Re: Help for a friend...

I agree with Jack .... besides if either switch has an effect on the lights .... sounds like they are working.

Excuse the crude ladder diagrams of the circuits .......

The top one shows the intended circuit and the bottom shows the existing.

Re: Help for a friend...

I see what you are saying. I guess it does point to a wiring issue and I was just mislead by my friend's insistence that it used to work. I would have dug into it a bit more but it was late when he mentioned it and I didn't really have the proper tools with me.

Just from looking at the switches it looked right to me which is why I posted here. Still doesn't explain why he thinks they used to work independantly when no recent work was done on them... but I'll let that go and just see if I can find the problem by opening up the fixtures.

Thanks all!

BTW - is it just me or is anyone else having huge lag times reading and replying to these TOH posts?

Re: Help for a friend...

BTW - is it just me or is anyone else having huge lag times reading and replying to these TOH posts?

Not just you ... I've noticed this as well.
Looks like they're using webops1 for security reasons.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.