Light fixture not on any circuit breaker?

I have recently moved into a house built in 1998. In repairing and upgrading some of the light fixtures and switches, I came across a light fixture, hanging from the ceiling over the stairs to the second floor, that does not seem to be on any circuit in the main breaker panel.

I systematically flipped every breaker in the box off and then on, one at a time, while my wife kept an eye on the light. It never went off.

How can this be?

How can I track down where this light is getting its power?

The previous owner of the house seems to have tinkered a lot: some of the wiring is a little odd. For instance, at least one 3-way switch was miswired so that it was a master switch instead of a real 3-way. So he might have done something unorthodox in wiring this fixture.

The light in question is on 3-way switches (but not miswired as above). Could one side be wired to one leg of the breaker panel and the other to the other, so that turning off one breaker at a time never cut power to it? Or is that not possible?


Have you tried cutting every inside breaker at the same time? Then turning them back on one at a time to see which one controls it?

I suspect you’ll find that two breakers turn it on, because the DIYer crossed two circuits.

It’s very, very unlikely that it’s wired in past a house circuit breaker. You’d have to go to some stupid extremes to do that. (I’ll stop short of saying it’s impossible, though… I’ve owned one too many houses after a “Home Depot genius” lived in it.)


I am guessing two circuit breakers – both on the same phase – are connected in parallel via a wiring screw-up.

Turn off all of the circuit breakers (except the main). And then turn on-off each circuit breaker, one at a time, while watching the light.

Bwah-ha-ha. You must be quicker on the Post button, grasshopper. :smiley:

Yea, you beat me to it. :smiley:


The power for the light must be coming through your breaker panel somewhere. It’s just a matter of time until you find which one.

Years ago, I did a handyman job for a woman and I couldn’t find which breaker turned off an outlet. It just so happened that her adult son had wired in TWO breaker panels coming off the main feed and was using the other breaker panel to control lights he was using for a “special agricultural project” he had going in a room in the basement.

I don’t believe that is the problem in your case; but you might want to look around JIC.

Newer houses tend to use fixture boxes more as junction boxes - in older wiring, you put a junction where you needed a junction, and used fixture boxes only to feed the fixture. I have a basement with perhaps eight light fixtures distributed across it, and every box has at least three wires going into it.

I’d bet the fixture box for the light in question has three or four wires and multiple connections in it, unrelated to the light, and that the prior owner didn’t sort things out right. OP should be prepared to pull all the junctions apart and sort them out, which can be tedious.

the likely cause, two breakers/fuses on the same leg/phase feeding it, illustrates why it is important to test any wires for voltage before touching them. you may turn off a circuit based on its label on the breaker/fuse box(es) and still have it be live.

This happened to me, also in a house we moved into in 1998 (but built a few years earlier). We bought directly from the builder, so no blaming it on a previous homeowner.

In our case, the 20A microwave circuit and the 15A kitchen lighting circuit were tied together. I plugged the microwave into a different circuit and kept the 20A breaker off for a while until I figured out where the problem was.

You’re not in the Ann Arbor are, are you?

Okay, this is what I suspected, but since I’m dangerously close to being a “Home Depot genius” myself, how should I diagnose and fix this once I find it? As I said, the fixture is controlled by two 3-way switches.

You’d be further ahead to bite the bullet and hire a licenced electrician to sort it out. You don’t want to make a mistake and set up a potential fire/shock hazard.

Confirm the diagnosis, first.

Is the light fixture box reasonably accessible? (I ask because I have one that’s 20 feet up in an entryway, and I’m going to have to get a scaffolding crew to paint that ceiling and replace the fugly chandelier…)

Basically, you’ll want to cut BOTH circuit breakers for safety (assuming the problem is confirmed), then go lower the light fixture off the box so you can see what’s inside. It’s possible the miswiring is somewhere else - in one of the 3-way switch boxes, or, worst, somewhere unrelated. But first things first - confirm the problem, then get the light fixture off to see how much wiring is in there.

Agree with AB.

So yea, first verify whether or not this is the problem. If it is the problem, you need to figure out where the two hots are tied together. This will require some sleuthing and poking around.

If you can’t figure it out, call a licensed electrician.

In any case, you need to fix this problem ASAP, as it possible the current configuration does not provide protection against over-current for some of the wiring.

The fixture is a hanging light on the stairs between the first and second floors. One switch is on the first floor, the other on the second. So I’m guessing the wiring mixup is in one of the switches: i.e., the hot of one switch is connected to a different circuit than the neutral of the other. That would create this situation, right?

So then the solution would be to disconnect one switch, power up one of the two affected circuits, test the wires to see which pair is energized, then rewire the switch with the non-energized line. Right?

I have seen one older house that had a line running to their detached garage. Killing the main breaker didn’t kill the garage light. I eventually figured out it was wired on the wrong side of the meter. It must of been like that for 50 years and no one had noticed.

Pretty sure it was a homeowner DIY mistake. A garage light wouldn’t draw enough power for anyone to deliberately cheat the energy company.

Possibly. But unless you’re hailing from Wonderland, it’s diagnosis first, prescription second. :smiley:

It may well be in one of the switch boxes instead of the light fixture, though. If those are more accessible, you might peek in each one to see what’s there.

Here’sa pretty good diagram and explanation of what you should be seeing. If there are extra cables coming into any of the three boxes (probably two extra cables), that’s the extra circuit the DIYer tapped into. The power supply cable shown coming into the light fixture could come into either switch box as well, although that’s nonstandard and possibly non-code in some areas.

I just watched the video on that link and I find it quite unbelievable that you can cram all those twisted wires, with uninsulated ground wires, into the back of a switch.

American wiring is very different to ours.

This is my vote, too. Yes, you probably can diagnose this one on your own… But whatever it is, you know that the previous owner did something screwy here. How many other screwy things did he do that you don’t even know about? And how easy will it be to fix all of them?

I’ve actually been trying to figure out how two hot circuits could be plumbed into the same 3-way circuit, and my inability to come up with an answer makes me start to concur. Maybe this is a job for a pro.

But the OP can still validate the conditions and possibly save some time and costs by letting the electrician know the exact problem.

we learn to be careful.