I am not so easily shocked nor do I wish to be shocked more often.
January 9, 2017 3:06 PM Subscribe
A dimmer switch in my house started shocking me recently. We investigated yesterday and the switch was not grounded (it is now). Did my wool slippers put me in jeopardy?
I'd like to better understand what exactly was going on, I will not be offended by ELI5 level explanations.
It's winter, which means that my house is drier than normal, and I have been shuffling about on wall-to-wall carpet in sheepskin slippers. The panel in question had three switches on it, two regular toggle switches, and one toggle with a sliding dimmer (just like these ones--same manufacturer). My house is in the US, and was built in 2005.
On Friday, as I was turning off some lights before bed, I received a relatively painful shock from the switch panel.
On Sunday, as I was turning off the same lights, I received an even more painful shock (and saw a little blue arc off of the dimmer). I touched the (plastic) panel with the back of my hand and noticed that it was warm. I confirmed with an IR thermometer that the dimmer switch was more than 20F warmer than the other switches in the panel. The lights had been on for a few hours but not dimmed.
I'm not one of those people who is plagued by static shocks, but a couple or three minor static shocks in the winter is not unheard of. That being said, I know that I haven't received a (noticeable) shock from touching anything electrical in this house because Mr. Motion has deployment-induced paranoia about bad wiring so I would have made a point to mention the weirdness to him (like I did on Friday).
We turned off the appropriate circuit breaker, and pulled the panel to find that the two normal switches were properly connected to the copper ground wire, but the dimmer was not. Since we didn't need a dimmer on the lights in question, and we had an extra normal toggle switch (like this one), we switched out the dimmer with the toggle (and grounded it). Taking apart the dimmer switch revealed no obvious signs of bad electrical things having occurred (blown capacitors, burnt electrical smell).
I understand why switches need to be grounded, but I don't understand what caused me to notice the shocking now and not before. Possible candidates include: time of year (but I was in this house all last winter), fuzzy slippers (I got them for xmas last year and may not have been wearing them much last winter), something to do with the bulbs (the switch fed a set of 6 recessed (can) lights, 5 of which are incandescent, one of which was recently replaced with an LED), or the dimmer going "bad" (caused by the lack of grounding? the LED bulb?).
tl;dr questions:
1.) What makes an ungrounded switch change from not-a-problem to a problem?
2.) If the fuzzy slippers caused a static buildup that caused the arc, did they put me in more danger of getting a serious shock? (you're not going to convince me not to wear fuzzy slippers, but it would be nice to know)
I'd like to better understand what exactly was going on, I will not be offended by ELI5 level explanations.
It's winter, which means that my house is drier than normal, and I have been shuffling about on wall-to-wall carpet in sheepskin slippers. The panel in question had three switches on it, two regular toggle switches, and one toggle with a sliding dimmer (just like these ones--same manufacturer). My house is in the US, and was built in 2005.
On Friday, as I was turning off some lights before bed, I received a relatively painful shock from the switch panel.
On Sunday, as I was turning off the same lights, I received an even more painful shock (and saw a little blue arc off of the dimmer). I touched the (plastic) panel with the back of my hand and noticed that it was warm. I confirmed with an IR thermometer that the dimmer switch was more than 20F warmer than the other switches in the panel. The lights had been on for a few hours but not dimmed.
I'm not one of those people who is plagued by static shocks, but a couple or three minor static shocks in the winter is not unheard of. That being said, I know that I haven't received a (noticeable) shock from touching anything electrical in this house because Mr. Motion has deployment-induced paranoia about bad wiring so I would have made a point to mention the weirdness to him (like I did on Friday).
We turned off the appropriate circuit breaker, and pulled the panel to find that the two normal switches were properly connected to the copper ground wire, but the dimmer was not. Since we didn't need a dimmer on the lights in question, and we had an extra normal toggle switch (like this one), we switched out the dimmer with the toggle (and grounded it). Taking apart the dimmer switch revealed no obvious signs of bad electrical things having occurred (blown capacitors, burnt electrical smell).
I understand why switches need to be grounded, but I don't understand what caused me to notice the shocking now and not before. Possible candidates include: time of year (but I was in this house all last winter), fuzzy slippers (I got them for xmas last year and may not have been wearing them much last winter), something to do with the bulbs (the switch fed a set of 6 recessed (can) lights, 5 of which are incandescent, one of which was recently replaced with an LED), or the dimmer going "bad" (caused by the lack of grounding? the LED bulb?).
tl;dr questions:
1.) What makes an ungrounded switch change from not-a-problem to a problem?
2.) If the fuzzy slippers caused a static buildup that caused the arc, did they put me in more danger of getting a serious shock? (you're not going to convince me not to wear fuzzy slippers, but it would be nice to know)
It's possible the dimmer failed in some way that applied line voltage to the front plate and therefor also to the screws of the cover plate. This is why we bond these devices. You are most likely fine to replace the toggle switch with a modern dimmer rated for LEDs (almost all are now).
sparklemotion: " touched the (plastic) panel with the back of my hand and noticed that it was warm. I confirmed with an IR thermometer that the dimmer switch was more than 20F warmer than the other switches in the panel"
This is completely normal especially with older non-LED/CFL rated dimmers. Even when they aren't dimming they'll give off heat because the electronics inside are still running. (You'll notice if you look that all dimmers have aluminum front plates which act as heat sinks and they may have instructions limiting the number and location onf multiple dimmers in the same box). If the dimmer you took out is not specifically rated to dim LEDs you can have problems though usually those problems are the LED doesn't dim properly.
sparklemotion: "If the fuzzy slippers caused a static buildup that caused the arc, did they put me in more danger of getting a serious shock?"
Not really. A injury or fatal shock occurs when the electricity in your house wiring uses you as part of a circuit. Wool is a pretty decent insulator unless wet (pre modern plastic it was used in some electrical equipment for that purpose); certainly not worse than socks or bare feet. And having bonded the new switch you shouldn't be at risk from that vector now anyways.
However you might want to pop open the other electrical boxes in your home and see if anything else is ungrounded; these kinds of, um, "shortcuts" tend not to be isolated to a single device. Especially an other dimmers which may have been installed by a handyman instead of electricians during construction (though we aren't imune to mistakes).
posted by Mitheral at 8:11 PM on January 9, 2017 [1 favorite]
sparklemotion: " touched the (plastic) panel with the back of my hand and noticed that it was warm. I confirmed with an IR thermometer that the dimmer switch was more than 20F warmer than the other switches in the panel"
This is completely normal especially with older non-LED/CFL rated dimmers. Even when they aren't dimming they'll give off heat because the electronics inside are still running. (You'll notice if you look that all dimmers have aluminum front plates which act as heat sinks and they may have instructions limiting the number and location onf multiple dimmers in the same box). If the dimmer you took out is not specifically rated to dim LEDs you can have problems though usually those problems are the LED doesn't dim properly.
sparklemotion: "If the fuzzy slippers caused a static buildup that caused the arc, did they put me in more danger of getting a serious shock?"
Not really. A injury or fatal shock occurs when the electricity in your house wiring uses you as part of a circuit. Wool is a pretty decent insulator unless wet (pre modern plastic it was used in some electrical equipment for that purpose); certainly not worse than socks or bare feet. And having bonded the new switch you shouldn't be at risk from that vector now anyways.
However you might want to pop open the other electrical boxes in your home and see if anything else is ungrounded; these kinds of, um, "shortcuts" tend not to be isolated to a single device. Especially an other dimmers which may have been installed by a handyman instead of electricians during construction (though we aren't imune to mistakes).
posted by Mitheral at 8:11 PM on January 9, 2017 [1 favorite]
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2. They do not make things more dangerous for you -- just electronics you like to touch. Shocks from the wall to you would require a return path; fuzzy slippers and dry weather actually insulate you more from electricity.
posted by flimflam at 4:43 PM on January 9, 2017 [1 favorite]