Unknown light switch

[DoYouKubuntu]

There's a light switch in one rarely used room that's a mystery to me. Turning it on/off has no obvious result. There are no ceiling or wall fixtures in that room. Turning it off does not affect anything plugged in to the room's wall outlets.

Just FWIW, I hadn't even thought about this switch in ages--until my live-in helper asked me about it recently. Since then, neither of us can STOP thinking about it!

I have a vague memory of asking my mom about it years ago--which, unfortunately, doesn't include her response. Maybe she didn't know either...

Aside from hiring an electrician, is there some way we can figure out what its purpose is?

[jglen490]

You could try to physically trace it. Or of you have a circuit "sounder" you could try to follow it back to the circuit breaker/fuse box, turn that off and see what else doesn't work. Or just remove the switch, tape the wires securely and separately inside the box, put a blank plate on the box, and paint it the same color as the wall ...

The safest thing to do would be to get an electrician with the right equipment to trace it for you.

[vinnywright]

There's a light switch in one rarely used room that's a mystery to me. Turning it on/off has no obvious result. There are no ceiling or wall fixtures in that room. Turning it off does not affect anything plugged in to the room's wall outlets.

Just FWIW, I hadn't even thought about this switch in ages--until my live-in helper asked me about it recently. Since then, neither of us can STOP thinking about it!

I have a vague memory of asking my mom about it years ago--which, unfortunately, doesn't include her response. Maybe she didn't know either...

Aside from hiring an electrician, is there some way we can figure out what its purpose is?

dose the room have electric baseboard heat ?

VINNY

[SpecialEd]

Does the room have access to an attic? Attic lights or attic fan?

[oshunluvr]

I had one the the utility room. Turned out there was a light fixture on the ceiling that someone drywalled over at some point.

You can pull the switch out of the box and test it to see if it has power. It it does you can track down which circuit it's on. That might give a hint. Most houses have lights on separate circuits than outlets.

If you really want to invest some time and a little bit on money in it., you could buy a circuit tracer, attach it to the wires in the switch box, and trace it through the wall.

[DoYouKubuntu]

dose the room have electric baseboard heat ?

No, Vinny, it doesn't.

[DoYouKubuntu]

Does the room have access to an attic? Attic lights or attic fan?

No, none of the above.

[DoYouKubuntu]

You could try to physically trace it. Or of you have a circuit "sounder" you could try to follow it back to the circuit breaker/fuse box, turn that off and see what else doesn't work.

Yeah...no!

Or just remove the switch, tape the wires securely and separately inside the box, put a blank plate on the box, and paint it the same color as the wall ...

That made me chuckle. But, no.

The safest thing to do would be to get an electrician with the right equipment to trace it for you.

That's kind of what I figured. My helper and I both have a healthy fear of electricity, since we're not educated in it--and it can be really dangerous. So we're not going to screw around with it ourselves.

As for hiring an electrician, the mystery switch has been quietly sitting there for decades, and will continue to do so until the next time I need an electrician for something else. It's not worth its own visit!

[DoYouKubuntu]

Thanks for the ideas, oshun. We're not going to screw around with it ourselves, out of sheer fear of doing something stupid!

I'm curious: how did you figure out the utility room issue?

[Don B. Cilly]

There's little gizmos that will let you find hidden wires, water pipes, treasures, etc. in walls.
They're basically mini metal detectors. Reasonably cheap too.
They're normally used to make sure you don't catch a wire or pipe when drilling into a wall :·)

[oshunluvr]

Thanks for the ideas, oshun. We're not going to screw around with it ourselves, out of sheer fear of doing something stupid!

I'm curious: how did you figure out the utility room issue?

Well, let me start by saying I'm a very experienced home remodeler, having done several homes and many projects of various difficulties. I even worked for an electrician for awhile when I was between jobs. This weekend I am removing a supporting wall and installing a very large beam in it's place Home electrical is rarely "dangerous" as long as you follow a few basic rules and apply common sense. First being to discover the circuit it's on and turn it off before mucking about with it, don't touch the business end of the power connections when working inside the main panel box, don't stand in water, etc.

If I were to do this, I would use a current "snifffer" to determine if the switch had power. These sniffers come in several types, the cheapest being a small plastic probe about the size of a Sharpie pen. You would probably have to remove the face plate, then stick the business end of the sniffer (it's plastic) near the wires on the side of the switch. If it was energized, you would get feedback from the sniffer - either a light or buzz or both. Then start switching off circuits on your main panel until you didn't get that feedback anymore. Then you would know what circuit it was on and likely be able to make a good guess what I was originally for. As I said, assuming your house was wired by a professional, normally lights and outlets are on separate circuits. Thus if the circuit that killed power to the switch also killed power to the outlets in the room or near by, I'd suspect it was an outlet switch. If the lights near the room - hall outside, closet, or room next door, etc. - went out I might infer that a ceiling fixture had been removed and improperly covered up.

The real question I think is "What are you going to do about this switch?" If this is just idle curiosity, I'd leave it be. If you want to use the switch for something, by all means, get an electrician in there. Even I hire an electrician when I have a big job to do because they can get it done so much faster than I.

If I were to bet, the odds are better than 80% it's attached to a light fixture that's been removed and covered (a code violation but a common stupid homeowner trick) OR there is or was a switched outlet in the room that you haven't discovered (or has been re-wired to remove it from the switch circuit). You may not know this but outlets come in pairs but can be electrically isolated from each other allowing one of the pair to be switched while the other is not. This is very common in homes with rooms having no ceiling lights that would rely on lamps to provide lighting - typically a bedroom. The very first thing I would do is plug a lamp (or hair dryer or whatever you can easily tell is on or not) into every plug in the room - top and bottom - and toggle the switch. Normally the down position is off so simply leaving the switch down while plugging into each outlet may reveal a switched outlet. Depending on the age of the house, maybe just removing the wall plate and looking will provide some answers. If the wires attached to the switch are both black - probably a light switch, if one is red - probably an outlet switch. If either or both are white, it's anybodies guess. If we knew more about the room - it's location and purpose, whether or not room additions or major remodels have been done in that area of the house, etc. - they might be other former uses for the switch.

As far as how I discovered the destination of the "switch of unknown function" in my utility room, I had the benefit of this utility room not being drywalled, so I could see a single set wires running up into the attic. This is a common way to wire a light switch when power is supplied in the ceiling box rather than from the switch box. I tracked it down by going into the attic and shoving the insulation aside, and seeing the box for the ceiling light in the rafters above the ceiling of the utility room. Long story is that the ceiling had been open to the attic and the room had originally been an outside utility room housing the main breaker panel and the well pump. 40 years later a garage was added to the back of house and this small room was enclosed in the new garage. For whatever reason, the light fixture in this small room was removed but the switch remained. Fast forward to when we bought the house - having an open ceiling in a garage that connects to the attic space of the home is a huge fire code violation and was noticed upon inspection (the garage also still had a window and door with a window in it looking into the kitchen - also a fire code violation!). The seller hired someone to install the ceiling drywall in the utility room but no one noticed (or cared) that there was an open box with wires in it just above the ceiling. Had the ceiling box been installed normally (extending 1/2 below the ceiling joists) the drywall installer would have had to cut a hole for it and I would have been able to see it and install a replacement light fixture. Instead, I just installed a light on the wall in the room rather than having to redo the old ceiling box with all it's wires in it. It is also serving as a junction box for other lights in that part of the house, mostly the garage. I assume the light was deemed unnecessary by the previous owner and the garage lights had been added to that circuit. The light was probably removed in an abundance of caution to reduce the load on the circuit. Now I've converted every light in the house to LED and am probably using about 10% of the former load. I even converted the four 8-foot double-bulb florescent garage lights with 8 foot LED's! Saved 320 watts, increased brightness, improved color, and zero annoying flicker.

[DoYouKubuntu]

Awesome post, oshun, and I appreciate your taking the time to post it.

The house is a mid-century (late 1940s, I believe), California, stucco and wood house in Arcadia. My grandmother bought it in 1971. To the best of my recollection, that room never had any ceiling or wall fixtures--and if it did, I can't imagine either my grandmother or mother having them removed, especially in a half-assed manner! Plus, the city's inspectors would never have approved it.

The room is basically a spare room; it has three doors--one to the living room, one to the kitchen, and a sliding-glass door to the patio. It's walked through, but rarely actually stopped in.

Its wall with the mystery switch on it has another switch at the other end--it's for the patio light. I have a lot of outdoor lighting, but all their power sources are accounted for.

There's no pressing reason to figure this out--just idle curiosity. It's one of those things that once you become aware of, you can't stop noticing it and wondering what its purpose was. I've walked past it a million times, without a thought...until now.