What is this hole in my wall and how do I fix it?
November 22, 2017 5:39 PM   Subscribe

My apartment is an old warehouse that had walls constructed to divide it into units. I have two holes in the walls that look like this.

They’re about 5 inches square. I tried buying some blank wall plates to cover them, but the screw holes are not in the right spots. How can I remedy these areas so they're not exposed?

I guess I could put art over them, but they're in odd spots. Any other ideas on what to do?

Also, what are the wires inside?
posted by Borborygmus to Home & Garden (14 answers total)
This is an open electrical box, you should be able to buy a cover plate for about 99c at Home Depot. You'll might need to remove a little more plaster/sheetrock at the lower left of you photo so it will fit. You need to attach the plate to the box, not to the two screws in the sheetrock (at the top of the picture).

There are two kinds of boxes, square and octagonal, and their cover plates are not interchangeable. You probably bought cover plates that fit the square boxes. An electrical supplier, or a Home Depot, should carry both.

The wires are probably connected to a circuit breaker somewhere. They may be live, but as long as the wire nuts are in place, you should be fine covering them up. Don't mess with them.

FWIW it is generally against building codes to permanently cover over a box like this, so you can't really patch the sheetrock. You could cover them with a picture, as you mentioned, or with some sort of removable access plate.
posted by mr vino at 5:51 PM on November 22, 2017 [6 favorites]

In addition to what Mr. Vino says, those wires are generally for marker or clearance lights since most residential lights have two hot wires and the neutral grounding wire (assuming the wiring is up to code otherwise it's a real possibility that both wires are hot which opens up what they can be used for). In this instance, the white is the neutral wire and the black is the hot wire. But as the previous poster said, you can buy a cover for about a dollar from any home repair store - for example, here's a Home Depot listing for it.
posted by lpcxa0 at 5:55 PM on November 22, 2017

Given that there is only one set of wires running to the octagon box, along with the several probably-drywall screws in the back of the box, and the placing of screws in close proximity, there's a strong suggestion that there is supposed to be something like a light fixture hanging here.

I'm unclear on the comment above that "most residential lights have two hot wires." 120 volt fixtures are a hot and a neutral.

Be sure to get a cover for a 4" octagon box, these are most common and easiest to find. Alternatively, see if you can determine if you are maybe missing a light fixture. It seems unlikely that you'd be missing an exit sign or smoke alarm, but these are also not entirely outside the realm of possibility.
posted by jgreco at 6:07 PM on November 22, 2017

Take this picture to the hardware store and ask for help.
posted by bonobothegreat at 6:26 PM on November 22, 2017 [3 favorites]

If you have an electrically minded friend who owns a multimeter and knows how to use it, you might have them see if the lines are live and possibly connected to a light switch. If both of those things are true, you can have sconce lights installed there, which will look nicer than simply covering it up.
posted by davejay at 6:44 PM on November 22, 2017 [3 favorites]

They make flat metal covers for those. You just have to buy the correct ones.
posted by humboldt32 at 11:18 PM on November 22, 2017

Grab a multimeter, unscrew the caps on the wires to get at exposed copper (or insert the probes in from the bottom, if they can be reached, without removal), and check for AC power CAREFULLY. If it's 0V, flip on and off light switches in the home to see if they're controlling it. If you get juice, instead of covering them up, put some nice lights in.

Don't do this unless you understand electricity and are reasonably sure you can do this safely without shocking yourself or shorting out the circuit.
posted by floam at 11:35 PM on November 22, 2017

If you do not own this apartment then get the owner to fix it, it's a building code violation.
posted by mareli at 5:39 AM on November 23, 2017 [8 favorites]

I would not permantly cover this up without resolving the electrical issue, it looks to me like this was used for a lamp on a switch - controlled circuit. The type of wiring looks mid-20th century. The metal box should be grounded via a metal cover on the wires outside the box.

To fix the wall cosmetically, lightly sand, fill the gaps with sparkle or wall compound, and repaint. You may have to repaint the entire wall to make the fix disappear.

If an electrician declares the wires to be irrevocably dead, the way to fix the hole is to stuff the box full of newspaper, and apply a smooth layer of plaster of Paris. Then spackle, sand, and paint.

Or if it's a wallboard wall and you can get rid of the box, get some scraps of wallboard. Cut a strip that you can maneuver into the hole and glue to the inside of the wall. Then cut a plug to fill most of the hole and glue it to the strip. Spackle, sand, paint.
posted by SemiSalt at 6:02 AM on November 23, 2017

You can see the earth wire tucked into the hole that the wires come in (see the small loop of plain copper wire bent back in there), plus that is a relatively new box, so this is relatively recent wiring not mid-20th century wiring as mentioned above. Could be run by a switch somewhere for a now-removed wall sconce, or the sconce could have had a switch right on it. If it is run by a switch, you won't know if it is still live until you know what switch runs it. I would bet it is still live and the previous tenant took their lamps with them. If this is a rental, get your landlord on it. If not, you can just cover it up with a metal plate, as mentioned above, then hang a picture or whatever over it. Or, you can have a light re-installed. You can't do anything else if the wires are still connected, as by code all junction boxes must be accessible (e.g., with a removable plate), you can't just plaster over it.
posted by fimbulvetr at 7:24 AM on November 23, 2017

Please don't stuff that junction box full of newspaper. If you're going to conceal it, please use the appropriate cover plate.
posted by humboldt32 at 10:41 AM on November 23, 2017 [3 favorites]

lpcxa0 said: "most residential lights have two hot wires and the neutral grounding wire"

Just to make one small correction here, most* household electricity wiring has the following wire leads in it:
- black "hot" wire (will definitely shock you)
- white "neutral" wire (could shock you, treat as hot)
- green or bare metal "ground" wire (can not shock you, is the safest wire there)

Describing them as "two hots" and "neutral grounding" is ... troublesome.

* exceptions for fellow pedants:
- 240V appliances like clothes dryers and HVAC units
- three-way switched lights
posted by intermod at 12:12 PM on November 23, 2017

The wires inside are Romex or a similar 3-wire residential wire with the outer jacket peeled back to expose the inner leads, as mentioned above the ground was pulled back through the plate; it's probably attached there or braided to some other hidden grounds. Based on the other screws and it being a terminal connection I'd guess there used to be a lighting sconce here, there wouldn't be any reason to get rid of e.g. a switch. By all means get a couple cover plates but you don't have enough information to cover them up permanently (and it's not your job).
posted by aspersioncast at 5:51 PM on November 27, 2017

Thanks for the advice! I found these did exactly what I needed.
posted by Borborygmus at 6:36 PM on December 9, 2017

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