Home>Discussions>ELECTRICAL & LIGHTING>How to find wire in a wall - to put a switch
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Bob in Michigan
How to find wire in a wall - to put a switch

I just bought a 30 year old house with a 15-foot high ceiling fan and light combo in the bedroom. There is no mechanical switch to control this fan/light. There is just an infrared remote control. The trouble is the light has developed the nasty habit of turning on all by itself, sometimes at 4 AM. I have to sleep with the remote close at hand to be able to turn it off quickly and get back to sleep. I don't think anyone is trying to drive me crazy by shining another remote through my bedroom window. I think the electronics in the ceiling have just gone flakey.

I would like to install a switch in the feed to this fan/light. The power runs through a wiremold along the ceiling and then dives into the wall. I have not found any switch that interrupts this feed, except for the breaker at the service entrance, which also controls some other outlets, so I don't want to cut it off there. If I knew exactly where the wire was in the wall, I wouldn't mind cutting into the drywall and installing a box with a switch. Is there something I can rent or buy for not too much money that will detect the wire - perhaps by an injected signal that can be picked up at short range? Or should I try to interrupt the feed up at the ceiling wiremold?

A. Spruce
Re: How to find wire in a wall - to put a switch

If there is a wire mold on the ceiling, then this fixture was an "after thought", meaning it was installed after the house was built, so your guess is as good as anyone else's how the wires are run. What I would do is go into the attic and find the wire penetration in the wall/attic area. If there are no controls other than the remote for this fixture, then it is likely that the feed was tapped into an always hot line, such as an outlet circuit. It would be my guess that it may be tapped off of whatever outlet is closest to the point it penetrates the wall. At any rate, turn off the breakers one at a time until you find the one that controls the fixture, and then figure out what else the breaker is controlling, this will narrow down your search for the source. Once you find the source, you can absolutely run a new control wire to operate the fan/light independently and physically from a switch, rather than a remote.

Mastercarpentry
Re: How to find wire in a wall - to put a switch

You mention wire-mold but not what's in it. If there are two runs of romex, then one will probably be for the light circuit and the other the outlets. If only one then you'll have to create a switch leg for the light in the existing circuit. Not too hard to do if you've got room above in the attic. If there is a separate run for the lights, a wire-mold box can be installed making a place for the switch.

And while up there you may find where the original wall switch was (if there was one). At 30 years old, if it were built to code there should be a wall switch, but without looking you never know and it may have always been a 'pull-chain' circuit without a switch. Look for two runs going into the same hole near the door, then seeing if one goes to the light box; if so then you've probably found it. It's against code to have an in-wall connection without a box that has a cover accessible from the inside of a room, but maybe they didn't care and covered the old box up in a remodel- it won't be the first time I've seen such as that. As long as nothing goes wrong it works, but without being able to inspect the connection you may not know that until you're calling 911 about the fire :(

Looking for wires entering walls doesn't require a detector and some of them aren't sensitive enough to work inside a wall but do OK closer to the wire. None I know of will work unless that wire is 'hot' or has a signal sent through it. A physical inspection is the way to go.

Phil

Fencepost
Re: How to find wire in a wall - to put a switch

Maybe you could try one of those devices the utility locating companies use, although your significant other may not appreciate the orange spray paint on the walls.

Bob in Michigan
Re: How to find wire in a wall - to put a switch
A. Spruce wrote:

... It would be my guess that it may be tapped off of whatever outlet is closest to the point it penetrates the wall..

Thanks. I should have realized that at first. When I looked inside the nearest switch box, it turned out that it did have the feed to the ceiling fan tapped off in that box. So now all I need to do is replace the single box with a double wide box with another switch and I will be in business!

A. Spruce
Re: How to find wire in a wall - to put a switch
Bob in Michigan wrote:

Thanks. I should have realized that at first. When I looked inside the nearest switch box, it turned out that it did have the feed to the ceiling fan tapped off in that box. So now all I need to do is replace the single box with a double wide box with another switch and I will be in business!

Not necessarily. You could install a stacked switch in a single wide box. Stacked switches come in two and three switch combinations, depending on what you have and what you're trying to do. A stacked switch will save you a lot of time and hassle of not having to change out the box, however, a larger box may be more preferred. Just trying to give you some options.

Bob in Michigan
Re: How to find wire in a wall - to put a switch

Well, thanks again, A. Spruce. I did in fact end up using a stacked double switch in the existing single-wide box. But as an epilog, I would like to report what I found in that box. I can see now how they did the retrofit without taking out any drywall. The back of the fiberglass switch box is busted out - completely. This allowed them to fish in a cable from the top, down through the wall, right to the busted out box. I don't think that cable can possibly have any strain relief anywhere in the wall, as I think is required by code. Nor is the contents of the box as well protected from sending out sparks and starting a fire inside the wall like it would be if the back of the box were intact. Some day I think I'm going to have to cut out a square foot of drywall and put a proper box in there - maybe just before the next time we repaint.

A. Spruce
Re: How to find wire in a wall - to put a switch
Bob in Michigan wrote:

Well, thanks again, A. Spruce. I did in fact end up using a stacked double switch in the existing single-wide box. But as an epilog, I would like to report what I found in that box. I can see now how they did the retrofit without taking out any drywall. The back of the fiberglass switch box is busted out - completely. This allowed them to fish in a cable from the top, down through the wall, right to the busted out box. I don't think that cable can possibly have any strain relief anywhere in the wall, as I think is required by code. Nor is the contents of the box as well protected from sending out sparks and starting a fire inside the wall like it would be if the back of the box were intact. Some day I think I'm going to have to cut out a square foot of drywall and put a proper box in there - maybe just before the next time we repaint.

Glad to have helped.

Let me save you a bit more work. You don't have to open the wall to change out the box. Turn off the circuits to the box you're working in, remove the switch, and then gently slide a keyhole saw between the box and stud to cut the nails holding it in place. Remove the remnants of the old box, then install a "cut-in"box. Slide the wires into the back of the cut-in box, slide the box into the wall, then tighten the screws until it is snug. Reattach your switch, install the cover plate. Grab a beer and admire your work! :cool:

As you can see in the pic, the cut-in box has wings that pop up and tighten behind the drywall, this is what holds the box in place.

Oh, and don't worry about unstapled wires in the wall, they are extremely common, especially in remodel work where new wires are run in existing walls.

Mastercarpentry
Re: How to find wire in a wall - to put a switch

Spruce beat me to it (again!) Good Job :)

Down here in the sunny south, the "cut-in box" he speaks of is generally called a "remodel" or "rework" box. Easy to do and you know why you need it (good for you!). Plus they come in a double version should you feel like not having the stacked switches.

Phil

A. Spruce
Re: How to find wire in a wall - to put a switch
Mastercarpentry wrote:

Spruce beat me to it (again!) Good Job :)

Now if I could only get you to put the silicone down and back the hell away! :p:p:cool:

I believe I've seen cut in boxes in even larger denominations, should the need arise.

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