How soon is my house going to burn down?
November 9, 2008 8:40 AM   Subscribe

When my living room lights are off, touching the screws on the faceplate for the electrical switch gives me a tiny little frisson of electricity. When my living room lights are on, I get a fairly painful shock from touching the screws on the faceplate. How dangerous is this?

The wiring in my apartment was done by the people who own the house and it leaves a lot to be desired in general, but I've lived here for 7 years and I've never noticed this problem before now. Either it's new, or it hasn't burned down the house in 7 years.

It could be new because:

I just changed some lightbulbs (the house has recessed pot lamps) in the living room. I think they're the right ones, but I bought inexpensive ones from Superstore rather than brand name from Costco. Is there any way that the lightbulbs could be causing this? I'm going to go take them out again and see if that makes a difference, but it's an epic pain in the ass (it took me half an hour to change them in the first place) so I thought I'd get a head start on posting the question.

A contractor's been doing some renovations on the house including some electrical work. None of that was in my apartment but if they did something somewhere else on the circuit could that be causing this?

I can't fix it and right now there isn't anyone else here who can, either. I guess my main question is not so much what might have caused this (though I'd like to know that) but how likely is it to be a major, dangerous problem. And would it be safer to have the lights on or off under the circumstances?

As a wrinkling factor, I have guests coming in an hour and a half to play board games in the room with those lights so I'd really like them to be on if that's safe (it certainly decreases the level of shock).
posted by jacquilynne to Home & Garden (21 answers total)
Response by poster: Following up on my own post, unscrewing the new lightbulbs (but not replacing them) made the problem worse -- the shock I get when the lights are out is now much more significant, and I'm officially scared to try it with the lights on, because I think it'd be a serious problem.
posted by jacquilynne at 8:45 AM on November 9, 2008

The latter is probably pretty serious, as in possible death serious depending on the exact nature of the fault. You've probably got either a neutral break or a hot leak to ground. This can be caused by incorrect wiring, defective appliance/fixture or defective wiring. At a minimum you should tape over the metal bits of the switch. Personally I'd turn the breaker off to that circuit, if accessible, until the problem was fixed.
posted by Mitheral at 8:49 AM on November 9, 2008

Response by poster: Unfortunately, the breaker to that circuit is the breaker to 80% of my apartment (this is a big factor in 'the electrical wiring job they did sucks'). It would take out my kitchen except for the stove, all of my lights except the bathroom, and all but two of my power outlets (in the bedroom). If other people agree that's how dangerous the situation is, I'll cancel my party and do it anyway.
posted by jacquilynne at 8:52 AM on November 9, 2008

it is a serious problem.

don't use it if possible, if not, put 2 layers of electrical tape over the screws.

it needs to be looked at ASAP. depending on what the floor is like, someone could die.

chances are you need a new switch, with a ground tab. they cost under one USD around here (NY state) and an electrician could change it in a few minutes.

or else the wiring is seriously flaky and it could take longer to find and fix.

it could be related to the work done elsewhere, but more likely not.
posted by KenManiac at 8:53 AM on November 9, 2008

It's not really that hard to replace.

And I am betting you are what is completing the circuit. I would feel fine to let it go through the day, unless you're smelling something weird in there.

But it also sounds like everything you're trying in troubleshooting is making it worse. It's going to be the switch wiring. Playing around with anything else is a waste of time at this point.

If the problem persists with a new switch I'd be surprised.
posted by cjorgensen at 9:00 AM on November 9, 2008

Response by poster: The floor is ceramic tile. I put tape over the screws and that's keeping it from being at all shocking, but I'm still very worried about the possibility of a short somewhere lighting the walls on fire.

Assuming I don't hit the breaker and take out the whole circuit (at which point, this thread might as well be over, because that'll take my internet access with it) is it better to have lights on or off? New bulbs in or out?
posted by jacquilynne at 9:04 AM on November 9, 2008

Here is a photo of a light switch. Do you see the two screws on the left? The hot and neutral wires wrap around those two screws. My bet is that when this light was installed, the hot wire was accidentally exposed to the metal frame of the light switch rather than correctly bent around the screw. The result of this is that the metal frame gets current, which is transferred through the faceplate screws. Chances are if you take off the switchplate right now and look, with the circuit breaker shut off, you'll be able to easily adjust the wire so it doesn't make contact with the switch (and then, ideally, wrap all the contacts with a length of electrical tape). I'll bet it's a problem that always existed but that you never noticed, and one that you can easily fix without needing to cancel your party. I am not an electrician.
posted by thejoshu at 9:12 AM on November 9, 2008 [2 favorites]

Sorry, that's a little technically incorrect. First off, it's a three-way switch, but either way, a length of hot wire will connect to each screw. Nothing neutral about it. Sorry!
posted by thejoshu at 9:14 AM on November 9, 2008

It sounds like something is cross shorting it, so I don't honestly think it matters on the on/off. I am not electrician, but seems like the circuit is being completed regardless of switch position.

I'd stop turning it on and off though.

It's probably been like this for some time, since wring generally doesn't spontaneously change, so would feel safe.

And you also have to think about what it would take to start a fire. Sure, a shorted plate or wire could get hot, you could get sparks, etc. But if it doesn't already smell funny, this probably isn't happening.

If it was my switch, I'd feel fine not obsession about it until tonight. Pull the breaker, go to bed, deal with it in the AM.

Or pull the breaker now, look inside, see if there's something obvious.
posted by cjorgensen at 9:17 AM on November 9, 2008

Yep. thejoshu has it.

I also want to point out that you should take precautions, but I've survived shock from this current quite a few times. It's unpleasant, but probably isn't going to kill you.

I know people can be a lot more afraid of this stuff than they need to be.

If you have your breaker pulled, it's safe to touch.
posted by cjorgensen at 9:20 AM on November 9, 2008

jacquilynne writes "Assuming I don't hit the breaker and take out the whole circuit (at which point, this thread might as well be over, because that'll take my internet access with it) is it better to have lights on or off? New bulbs in or out?"

If it's a neutral break removing all loads up stream of the break will mitigate the problem until it can be fixed however you probably don't know the topology of your circuit. Removing the bulbs may help. If it's an appliance that is shorting then unplugging that appliance will fix it. If it's a short/leak on the hot side then there is nothing you can do to reduce the risk short of turning off the power to that circuit.

This probably isn't simply a switch problem. thejoshu's scenario requires a missing or bad ground as well as hot contact with the frame of the switch.

Just because you have just noticed it now does not mean you are safe. An Arc-Fault failure often creeps up like this [PDF] and is thought to be responsible for around a third of all residential electrical house fires.
posted by Mitheral at 9:26 AM on November 9, 2008 [1 favorite]

110 volts can stop your heart. It doesn't cause any permanent damage, except death.
posted by weapons-grade pandemonium at 9:26 AM on November 9, 2008

Well, my scenario doesn't require hot contact with the frame, that's just what my scenario is. It's also easy to imagine a nonexistent or faulty ground in an old house or one that's been wired by a layperson.

Ultimately, though, my point is just that the OP can easily (but carefully!) remove the faceplate and quickly be able to tell if it's a really simple or a more complex issue.

And then get back to the pressing matter at hand, which is playing board games.
posted by thejoshu at 9:36 AM on November 9, 2008

Allow your friends to come over. I bet you one of them can look at it and see what is wrong and, odds are, do a fix for you so you are safe even after the party.

Free advice is always good.

I have replaced/fixed switches easily in a matter of minutes. It shouldn't take too much time out of the party (10-15 minutes). But it you don't 'get' what you are doing, don't do it yourself.

Worst case scenario, leave the lights off and have an adventure by candlelight. It will be a more memorable party.
posted by Vaike at 11:16 AM on November 9, 2008

"I know people can be a lot more afraid of this stuff than they need to be."

120V is one of the few times that being more afraid of something than you need to be is a good thing. I don't think your house will burn down (but IANAn electrician), but please, please, please don't go fiddling with the light switch fixture at all without turning off the breakers and posting a "Do not turn on or I'll die" note over the breaker.
posted by fogster at 12:56 PM on November 9, 2008

How serious is it? It could kill you. If you take a hit while the heart is contracting, you'll probably live unless you have an undiagnosed heart problem. If it catches the rest between beats, it can simply stop and never restart. (All that medical stuff on TV with discussions of a "shockable rhythm? You can restart a lot of things, but once it goes flatline, not so much.)
In terms of fire, it's possible for every wire in the house to get hot at the same time if the circumstances are right.

There's a lot of speculation here but really, it could be anything, up to and including a lost ground on the house main. It usually comes off the pole at 220 VAC, and you can lose the ground at that point. I very nearly lost a kid that way. In her case, in lieu of the lost ground, the 220 was trying to ground itself via the plumbing, including the shower.

You mentioned the wiring was done by "the people who own the house" and a crappy job of it, which makes them responsible for it, legally, morally and financially. There's no good reason not to just make them fix it, especially considering it may have more than one problem.

Risk vs. benefit, I'd shut it down, and have the party by candlelight. It wouldn't hurt to know where the fire extinguisher is if you're having liquor.
posted by unrepentanthippie at 2:55 PM on November 9, 2008

Tell your landlord. This is not your problem to fix and you may even violate local codes in replacing a switch. If you know so little about electricity you suspect the lightbulbs, trust me, you don't know enough to fiddle with an electrical switch properly. I think I know what I'm doing and yes, I've gotten shocked.

A short to the faceplate is a shock hazard and may well indicate a fire hazard because of a worn insulator or loose connection. So have the landlord get it fixed pronto.
posted by dhartung at 2:56 PM on November 9, 2008 [2 favorites]

(I'm probably doubling with one of the above posters.) For now, cover the switch with something insulating (plastic sheet; or Tupperware might look cool ...) and get a licensed electrician to it asap. Wear rubber gloves when you turn it on and off. Turn off the circuit breaker or pull the fuse, if possible, in lieu of operating the switch. Keep your friends away from it. From your questions, it appears you don't know much about electric wiring, so don't mess with it. Cost be damned, please get thee to an electrician.
posted by JimN2TAW at 3:36 PM on November 9, 2008 [1 favorite]

Lots of good answers here. Don't be too worried about fire, yes that is a possibility, but it is probably not a very high probability. The thing to worry about you have already taken into account, shock. A tile floor is more dangerous than wood etc. Wear shoes (rubber soled if possible) and don't touch those screws. The danger is really that if this is a problem bigger than the switch, such as a floating ground, then it could affect other things such as your appliances which are harder to avoid touching. Get in touch with your landlord and have it fixed promptly (don't take no or excuses for an answer and if you get resistance report it directly to the utility and to the building inspector). There is danger, but knowing this you can protect yourself until it is fixed and the one danger you can't easily mitigate, fire, is pretty low, at least in the short term. The problem is that it can make sparks when you plug something in or move the switch, or even perhaps at other times. It's a real danger, but if you are getting stuff repaired in the next few days it isn't one that I would obsess over (and if you check my posting history here, this is a big hot button danger of mine).
posted by caddis at 3:45 PM on November 9, 2008

Response by poster: So, in a bout of continued nerves, I called my uncle, the house builder and my friend, the electrician. (How did I fail to remember earlier in the day that one of my best friends is an electrician? I don't know.) Both seem to agree with many of the people here that if I just shut the lights off and stop touching them, it'll be okay for awhile.

So I'm continuing to try to reach my landlady's son to come and fix it. Otherwise, my friend the electrician will stop by on Tuesday and change the switch for me. Thanks Ask.Me.
posted by jacquilynne at 6:21 PM on November 9, 2008

Response by poster: So, to end this, there was some significant problem with the wiring, though no one's quite agreeing precisely what it was. 40 volts were mysteriously draining into the switch box, hence the shocking shocks.

Inspecting the actual pot lights controlled by the switch demonstrated that some of them were showing signs of the wiring heating up and burning stuff, so all of those got replaced with apparently newer and less likely to burn stuff down models.

They swear that there's no longer voltage draining into the switch, but they can't tell me why it was happening in the first place.

They also rewired half of the rest of switch boxes in the house, since apparently most of them had two wires backwards in them or something? I'm not sure that problem was any more serious than 'we used the wrong coloured wires for these two things', but it did seem to be confusing them, and they had to redo some of those switches anyway given the other renovations.
posted by jacquilynne at 6:09 AM on December 10, 2008

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