Bum switch? Or worse?

January 17, 2012 6:43 PM

Did I get a bad box of light switches, or is something else amiss?

Recently, I have been finishing my basement, including all the electrical wiring. After replacing a ceiling fixture in a bedroom the other day, I noticed that the light switch seems to make a small 'popping' noise when you flip the switch. If you flip it slowly enough, you get more pops, accompanied by a faint yet noticeable electrical smell coming from the box. No smoke at all, and you have to get your nose right by the box to smell it (the other side of the wall this switch is on isn't drywalled yet).

I did find this previous AskMe that describes my exact issue, but I would like to expand on that a little, as this is a brand new switch that was one of a generic bulk 10-pack I bought on the cheap. Is it possible that I just got a bum switch? Is there anything besides a defective switch (or a poor job attaching the wires) that would cause this behavior? This is one of those types where you simply strip the wire and push it into the hole in the back, no screws involved, so I cant imagine it would be that hard to mess up. 15a circuit, simple one-way switch with a single hot and neutral lead (+ ground).

Just want to be sure that I don't have anything more sinister going on. I didn't add load to the existing circuit, which was new with the house in 2003; I simply split the 6 basement lights from all being on one switch to being on their own switch in the new rooms that were built. In the room in question I did also replace a standard ceramic ceiling fixture with a drop ceiling recessed light.

I did test other switches down there, and found one more that seems to pop a little if you flip it slowly, but other switches are fine. I'm going to buy new switches regardless, but would love to know if I should be looking at something else, or returning the noisy ones as defective.

Thanks!

posted by SquidLips to home & garden (5 answers total)

Is it possible that I just got a bum switch? Is there anything besides a defective switch (or a poor job attaching the wires) that would cause this behavior?

No, and you shouldn't be able to throw modern wall switches "slowly".

I'd just replace the switch. I usually wrap a piece of electrical tape around the switches over the contacts once I've screwed the wires in, just because. Are these switches two side by side, or just one?
posted by mhoye at 7:38 PM on January 17, 2012

The 'popping' makes me think that this is a grounding issue. Have you checked to make sure that the switch is properly grounded? And have you made sure that the wiring to the light isn't getting wet somehow?

AnecdoteFilter: My old high-school girlfriend lived in a renovated room above her parents' garage, and whoever wired it didn't take into account that the roof leaked right into the junction box. When it rained it would pop all night long. Although I didn't complain because it frightened her right into my arms.
posted by Sphinx at 8:15 PM on January 17, 2012 [1 favorite]

This is just a single gang; the other switch I found to make pops is in another room.

I will certainly double check the ground wire to make sure it didn't come off or is loose or something, but everything should be properly grounded.
posted by SquidLips at 11:34 AM on January 18, 2012

I wonder if you might have accidentally gotten the switch in the neutral wire going to the bulb instead of the hot wire (see the diagrams on this page), especially since you rewired the light fixture itself.

I did that once, and the sparking when I turned it off was much stronger.

My explanation was that either way, turning the switch off caused an arc to form, but because the induced potential in the hot leg had to work against a rapidly varying (60 Hz) EMF across the gap, it would produce conditions that extinguished the arc sooner than the neutral leg would.

If this is the case, the wires in the light fixture will be hot with respect to ground when the light switch is off, and you can see that with a voltmeter or one of those nifty little lights all hardware stores seem to have these days.
posted by jamjam at 3:39 PM on January 18, 2012

So it turns out, on this specific switch, I had used a 3-way switch for this single-pole light. (I bought the box in bulk with the understanding that 3-ways could be used as single-pole.) I did replace that switch with a normal single pole switch that I purchased new, just to be safe.

The other thing I did on both switches is moved the connection to use the terminal screws on the side instead of the push-in quick connector on the back. Did some research and there was an abundance of 'don't use the push-in connector, use the screws' proponents online, so I moved them and will probably do the same with the other newly installed switches.

With the two altered switches, and eventually with all the others I put in new, I wrapped the sides in electrical tape. Not really sure why I didn't do that to begin with, but it makes sense.

I now have no more popping on either switch. Thanks gang!
posted by SquidLips at 4:45 PM on January 22, 2012