In my house, I fortunately have a well-labeled circuit breaker. There are a few rooms that could be better named, but it's fine.
As such, it's very easy to identify almost every switch and what it does and what breaker switch it's attached to.
Except for one light switch at the entry way of my house.
I turned it on and stuck a voltage tester next to it. I went through every single breaker switch, even the ones for other floors, and the voltage tester continued beeping. I skipped the doubles (washer, dryer, and HVAC), because I assume a light switch wouldn't be connected with a major appliance.
I've also tried plugging a light into various outlets and turning the wall switch off and on, but I don't see any change in the light.
The voltage tester only stopped beeping once I turned off power to the entire house. So as far as I can tell, this switch seems to do nothing.
- Is there another method I can use to trace what this switch connects to?
- What should I do with this switch?
Update: I have finally figured out where this mystery switch goes to: an outside outlet. I never even noticed it until y'all pointed it out so thank you! I still don't know which breaker it goes to, which is annoying but I've got at least half the mystery solved
Update 2: I have found it! Once I realized it went outside and was GFCI, I guessed that the cable was connected to the Basement GFCI circuit and that did it. Personally I would have labeled it "basement + outside gfci" or wired it to the first floor outlets or put it on a separate breaker but it's fine. I'm not bitter at all
Best Answer
Divide and conquer.
You turned off the main breaker and the switch went dead. So you know it is going through that panel.
If it is still on at this point, then you have something really strange going on - time for a professional. But assuming that does turn power to the switch off:
This will take a while, so you can also try:
If it does, then turn half off and see if it is on or off. Lather, rinse, repeat. If you have 32 breakers, the first test gets you to 16, the second to 8, the third to 4, the fourth to 2, and on the fifth test you have your answer.
As far as what the switch does, is there any chance you have some outside lights that don't work properly? Also look for any receptacles or covered junction boxes (which might previously have had a light on the switch) outside.
Update: Now that you have determined the switch controls a receptacle, there is an easy way to find the breaker if you don't have a helper (i.e., if you have to run between breaker panel and switch/receptacle to test):
For anyone wondering why "turn off one at a time until the music stops" instead of "turn on one at a time until the music starts", this gets to the "old vs. new equipment" issue. An older radio has a simple power switch. Turn it on and unplug it and plug it back in and it is guaranteed to be "on". Many newer radios (like TVs, computers, etc.) have a power switch that does not really turn everything off. A small circuit stays on to power a clock, status lights, etc. For normal usage that's just fine. But the default behavior (sometimes configurable, sometimes not) for these devices is typically "on external power restore go to 'off' state", which wouldn't be very helpful here.