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During the night, I accidentally bumped into my light switch, jamming it in towards itself. Now, the lights in my room will sometimes flicker on and off very quickly when after turning on the lights. My mother, who has no experience with electrical work, wants to unscrew the light switch cover and see what's going wrong. Is this safe? I'm suggesting that we call an electrician, but she wants to inspect it herself first.

  • I would be amazed at damage that would leave the switch even partially functional and would be visible from the outside. – Loren Pechtel Apr 23 at 4:53
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    Sounds like it's a digital switch. And it's broke. Inspecting it with do nothing. If it isn't a digital switch, then it's arcing and should be left off until replaced. – Mazura Apr 23 at 5:08
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Removing the cover to look at the switch is safe IF you first turn off power to the circuit at the breaker panel. If you aren't completely sure which circuit it is, then either turn them all off, or double-check with a multimeter or non-contact voltage detector.

However, most likely you will not be able to see what's wrong with the switch because the damage will be inside the plastic housing. Since basic light switches cost less than $1, I'd recommend just replacing it. It's a simple task that's easy to DIY. Here's one guide, or you can find a dozen others by googling how to change a light switch.

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    Of all the advice you could provide, you began with the best. Something can go wrong, but no one gets hurt if the breaker is off. – fred_dot_u Apr 22 at 19:17
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    It's possible that the connection wires are grounding off the housing box. Simply prying the switch back into it's correct place might work, or if the wires aren't secure in the screws, they can be tightened. But it's more likely that the switched needs replaced, if it's been hit so hard it's deformed. – computercarguy Apr 22 at 21:38
  • It's also possible that the wires connect to the switch by means of back-stab connections. These are notoriously unreliable and should be redone using screw terminals. If you aren't absolutely certain as to how to do this, call someone who knows. – Phil Freedenberg Apr 23 at 12:12
  • "Double check with a voltage detector": You need to check the voltage detector detects live by checking it on a known-live cable first then you can use it to check if the possibly live cable is live. – Martin Bonner supports Monica Apr 23 at 15:08
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I tend to agree with Nate: switches are cheap so replacement is the best course of action. When you go to the hardware store for a new one, if you're presented with a choice of switches, buy the slightly more expensive one (sometimes called Preferred). Most likely you need a 15 Amp switch. Here's a breakdown of what you need to do

  1. Turn the light on (it doesn't matter if it's flickering). Now, go to your circuit breaker. Flip breakers one at a time until the light turns off (if you're lucky it will be labeled, but that's pretty rare)
  2. Remove the face plate. If you want to be sure it's off, use a contactless detector to verify the wires are not hot (unlikely since the light is off).
  3. Unscrew the switch from the box and pull it out towards you. You should see 3 wires attached (one will be bare). If you have more than three wires it might be best to stop and consult an electrician
  4. Unscrew the three screws on the sides of the old switch (one ground, one hot and one switched hot)
  5. Screw the wires onto the new switch. For simplicity, try to keep them in the same location, but only the ground (bare) wire has to go in the same location (attaches to the green screw on your new switch). Make sure you get these connections tight
  6. Screw the switch into the box
  7. Flip the breaker and test to make sure the switch works.
  8. Replace the face plate cover

If replacing the switch does not fix the issue, you might want an electrician, but it sounds like the switch is the culprit so this should fix the problem.

  • You forgot the assumption that the breaker might not be wired properly (switched neutral), so don't just assume it is safe... – Sean Houlihane Apr 23 at 13:25
  • @SeanHoulihane True, but that would be an edge case. There's also a possibility this is an improperly done neutral as well – Machavity Apr 23 at 13:41
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My qualifications; Retired C-10 (electrical contractor) A wire is loose, or switch is bad. In most cases, if it arcs with the "box" or neutral or ground it will trip the breaker. It is supposed to trip the breaker is the better way to state this. If you don't want to call an electrician (my suggestion) then do the following-

Turn off ALL breakers in the house panel at the MAIN, not sub-panels. If you don't know what that is, call an electrician.

Take a tester, most hardware stores will have these (see pix). All you have to do is touch around the switch in the box, make sure no electricity is on. Note- there could be other wires coming through the box that is not on the same breaker. If you don't have a tester or want to buy one. Call an electrician.

No electricity, proceed. Pull the switch carefully forward. If the wiring is really old. Call an electrician, messing with old dried out wire is an art.

If the wiring is fairly new, great proceed to pull the switch out as far as you can. Take white tape mark the wires where they screw into the switch; "top" "bottom" or Line and Load. Electricity should be off before you do this. If you see more than two wires on the switch. Call an electrician - you are dealing with three or four-way or a digital timer.

You may see a GREEN wire soldered on the switch, it's supposed to be connected to the box as a ground. In residential (mostly) green and neutral tie to the same panel bus. Is ground important? YES and if it's not tied to the box, call an electrician

Ok now unscrew the wires on older switches or find a small tool to slide into the wire release on the back of the switch. If you don't understand what I am saying, call an Electrian.

Now replace the switch with a new one and reverse this process.

Word of Caution most fires in homes are caused by faulty wiring practices or cooking- is it worth your life not to call an electrician. Just saying. Be safe and replacing a switch seems easy till it's not.

Peace Respect Forwardenter image description here

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