Finding wires behind wall

Someone I know has a 2 story house from around the 1930s. There is a room with a wall switch, but no overhead light, and he knows at some point the celing was redone in plaster. He suspects the ceiling light socket is there, but not sure of the exact location and does not want to tear up the plaster looking for it. Is there any way to determine? I suggested a stud finder, but they don't work well on this plaster cause it is textured and the thickness varies so much.

Thanks in advance.

Reply to
borne
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First make sure that wall switch does not control a nearby duplex receptacle (or one outlet of a duplex receptacle). There may be no wires going to the ceiling at all.

Reply to
Marilyn & Bob

I would try a metal detector. Doesn't need to be fancy or expensive; a kid's toy model might work, especially if the box/hanger is still there.

If that doesn't find anything, you can go for something more hi-tech.

Jim

Reply to
Speedy Jim

There are stud finders with a "deep sense" position. If you use that feature with a 1/2 inch styrofoam spacer between the sensor and the ceiling, it will make the plaster thickness variations have a much smaller effect and yet you should still be able to sense some metal behind the plaster if it is there.

The switch controlling a floor outlet is also a very strong posibility. It may just control one of the two outlets in a duplex outlet.

Reply to
hrhofmann

Without invasive action (cutting, drilling, etc) the only way to locate the wires is with a test probe. An amplified test probe is the most convenient model but none are cheap.

Such test equipment is used heavily in the telecommunications industry, particularly in legacy telephone facitilies to locate a single pair in a cable or enclosure containing many hundreds or thousands of pairs. The probe SHOULD reveal the location of wires as long as they are connected to a working (or workable) circuit, energized or not. Disconnecting the wires at their source, then adding a locating signal, might improve locating success.

A good metal detector SHOULD work to locate the BOX from which the original fixture hung as long as it is still there.

If this house was indeed wired in the 1930s, it is reasonable to expect that every room had a ceiling fixture generally dead-center of the room with the possible (though unlikely) exception of the living room. It is surprising, however, that when the ceiling fixture was abandoned (if it indeed existed), the box was not simply covered with a blank plate. It is unlikely there would be switch-controlled wall outlets from that era. Of course, that possibility should be investigated. Good luck!

Reply to
Jim Redelfs

A house that old may have had 'knob and tube' wiring which you wouldn't want to use even if a light box is there. Pull the switch out and see if it has modern 'Romex'. in the box. (Plastic insulation on wires vs cloth like fiber). Even that though won't tell you what if anything is in the ceiling. Most probably the switch controls an outlet in the room. Usually it is the closest outlet to the switch but does not have to be. When I wire switches to outlets in a room I usually run the switch wire to all outlets and wire 1/2 of each duplex on the switch. That's addition to an overhead light. FYI - I believe the NEC code states that minimum a room must have either an overhead light or a switched outlet. Kevin

Reply to
Kevin Ricks

I disagree.

Knob and tube wiring, if installed properly, not modified improperly and behind proper overcurrent protection, is perfectly safe and useable.

Second-floor and/or inaccessible (hidden) K&T wiring should be of no concern.

Reply to
Jim Redelfs

On Mar 5, 5:16=EF=BF=BDpm, Jim Redelfs wrote= :

yep anything thats 80 to 100 years old and older is perfectly safe: ( after all it was approved when installed, and code 100 years ago was certinally safe and effective.

lots of bad things can occur with wiring thats 100 years old.........

Reply to
hallerb

You would probably want to add a ground however if you plan on adding a metal light fixture.

nate

Reply to
Nate Nagel

measure and find the center of the room. that's where the ceiling fixture used to be. I'd almost bet on it. We rehabbed one house that they had put a false ceiling in the front room. Not only were the wires still there, the damn fixture was still attached to them. They just left it ontop the new sheetrock and went on.

s

Reply to
S. Barker

Given my original qualifications, I agree.

Yeah, probably by the installer's BOSS.

They had a wiring code in 1908?

Uh, like what? (Please constrain your examples to within my previously-listed qualifications.)

Some days ago, in a different thread, I said that I thought that your words were usually worthwhile. I was mistaken and humbly apologize. I was thinking of another regular here. You, on the the other hand, are surely a charter member of The Tin Foil Hat Society.

Reply to
Jim Redelfs

Before Romex came BX. Two or three insulated wires in a 1/2? inch metal coil. I don't think anyone will remodel a light circuit that isn't being used at the time, and living room ceiling lights were iirc passe before Romex was invented.

I too don't think this is likely in a house this old. The first time I saw a wall switch controlling an outlet, I thought it was the work of Satan.

Reply to
mm

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$15

Reply to
Mike Dobony

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