Weird light failures
April 25, 2022 6:25 AM   Subscribe

What's going on with my lights this morning?

Our stair lights (2 wall sconces) have a switch at the bottom and the top of the stairs. This morning, the switch at the top of the stairs didn't work when I first tried it, but when I got to the bottom of the stairs, that switch turned the lights on. When I walked back up the stairs, the top switch was working again.

Another switch controls 5 overhead lights downstairs - 4 in a room, and 1 just outside the room's entrance. The 4 lights in the room no longer turn on, but the 1 outside the room does.

As of Saturday, all of these lights were working fine. Maybe they were fine on Sunday as well, but I don't remember using them.

Is this dangerous? How urgently do I need to call an electrician?
posted by congen to Home & Garden (5 answers total)
 
I have the same setup for my stair lights and this happens occasionally. One of your light switches wasn't fully engaged/disengaged. You can reproduce the behavior by moving one of the switches to the middle position (eg, not off or on). Then the other switch won't work.

As for your 5 light setup, sorry, I don't know what the problem could be for that.
posted by mezzanayne at 7:38 AM on April 25, 2022 [1 favorite]


One of the switches of your stair lights I s starting to fail. (It’s not latching reliably, which is why flipping it again works. Try flipping them very gently to see if you can recreate the problem to narrow it down to one or the other.) Wall switches are robust and it is very unlikely that it will fail in a dangerous way. But yes, a switch needs to be replaced. The problem will slowly get worse.

I feel like the overhead light behavior is a coincidence, unless your house was recently struck by lightning.

What kinds of fixtures and bulbs do you have in your lights?
posted by Ookseer at 8:01 AM on April 25, 2022


Response by poster: The lights in the downstairs room are closed wall sconces with dimmable 5w Phillips led bulbs in them. The bulbs are fine - they work in other lamps. All the wall sconces just stopped working at the same time. The wall sconces are all about 20 years old.
posted by congen at 8:44 AM on April 25, 2022


Response by poster: And just as mysteriously as they stopped working, all the lights are working again!
posted by congen at 8:48 AM on April 25, 2022


Best answer: Two way switches can be confusing; they have two wires that could potentially be "hot", with only one hot at a time, and which one is hot depends on the combination of the two switches' positions. It may be that one of them is loose, and when the downstairs switch swapped the hot line when you flipped it, that's the wire that isn't loose. Then the upstairs switch is now flipping between the loose wire (which is not energized, so 'off') and the hot wire from downstairs.

Have you tried putting the downstairs switch to its original position and seeing if the upstairs switch goes back to not working?

The 5-light thing also seems like a loose wire, probably in the electrical box above the one working light, or possibly at the next light in the 'chain' -- house lighting is wired in parallel so it's not like old xmas lights where one goes bad and all go out, the break is at the spot where a working circuit connects to a non-working circuit (most of the time).

I don't think the two are related, although if there were two loose connections and there was a power surge which caused arcing, they could have been both affected by the same thing but that's unlikely.

To answer the question: could this burn your house down? My answer is yes, but low likelihood of that happening. Loose connections can arc and start fires so I can't tell you it won't ever happen. For peace of mind calling an electrician out wouldn't hurt. While the stair-switches could be a bad switch, which is less risky, the ceiling lights having part go out while others are working is a bigger risk since it likely is something happening within your ceilings/walls.
posted by AzraelBrown at 9:34 AM on April 25, 2022


« Older A Korean index fund explainer   |   ISO A list of "every" food/ingredient Newer »
This thread is closed to new comments.