My husband and I hung a mirror centered in between an outlet and a light switch. The outlet is about 14 inches off the ground, the wall switch is about 48 inches off the ground, and the mirror was hung 75 inches off the ground. We used a french cleat that had five screws at 1 3/4 inch long that were hand screwed (no drilling) into the wall.

We used a stud finder with a live wire sensor before hanging the cleat - the sensor showed the entire wall was 'live'. Figuring that the wires were likely to travel down from the switch to the outlet and that we were hanging the mirror above those, we turned off breaker and installed in the cleat.

Upon turning the breaker back on, I've noticed that the light switch is making a popping sound that I haven't noticed before. My biggest concern is that we may have hit a wire with one of the screws. Is there a way to see if we hit a wire?

Without cutting the wall open... tricky.

You forgot to consider it also ran up that stud into the ceiling like many I have seen do.

I'd say the odds you hit the romex in the wall is 99.99%.

But really if you did and its been popping that means its arcing and there is damaged and burned insulation and needs fixed before you have a fire.

Remove your screws and see if the noise goes away. You could buy or rent a Amazon.com: milwaukee tools camera so you could look inside the wall after making a small 1/2" drill hole behind the mirror

Thank you for the replies! We think we are going to take down the cleat and see if the popping noise continues. If it does not, does that mean we are in the clear?

@ Smoothy, your thoughts are that we did in fact screw into a wire? Thank you for explaining arcing, very clear!

Sorry but no, if the noise stops that means you did nick the wire and it must be replaced. Back to you for your results

I am going to disagree.

Quote:

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1 3/4 inch long that were hand screwed (no drilling) into the wall.

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Assuming that the material you made the French cleat out of is 3/4" thick and your drywall material is 1/2" thick, that means that your screws only penatrated the drywall by 1/2".
Assuming that your wall is a standard 2x4 wall, any wiring would be in the center and 1 1/2" away from the drywall material. Any closer than that and a metal plate should have been installed to prevent you from hitting the wiring with a nail or screw.

Even if you hit a wire with a screw, that would not cause the switch to to make a popping noise. Either the noise you hear is normal or the switch is defective.

Any popping sound caused by arcing caused by hitting the wire would be at the screw not at the switch.

Chances are that this is just something you simply didn't notice before. Only notice it now because you are worried. If it makes you feel better replace the switch.

Hi hkstroud, thanks for the reply!

We used a manufactured cleat by Ook - http://www.amazon.com/OOK-55316-13-Piece-Hangman-Hardware/dp/B003WE9XU4.

I've read quite a bit on the metal plates but am not sure that they were installed in our home (built in 1979). We do know that we didn't hit a stud or anything hard upon putting in the screws. It is definitely possible we didn't notice the sound before and replacing the switch is a great idea - thanks for sharing!

Do you think it is possible to use a voltage meter and test each of the screws?

Ok, so that is a metal bracket, Your screws probably penatrated the wall by about 1". Chances of hitting a wire are remote. Even it you hit a wire in between the studs the wire would have most likely simply moved to one side. Metal plates would have covered studs because wire could not move where it passes thru stud. That is only done when the hole thru the stud is less than the required 1 1/4" from surface of stud.

If you did not put any screws in studs chances of damaging a wire are very small.

Describe popping noise. Do you mean a poping sound when switch is turn on or turned off. Or do you mean there is a popping noise the entire time the switch is on.

No, volt meter won't tell you anything.

I take that back. I guess you could use a meter to test if any screw has voltage, but you will have to rigg up a connection to ground.