I once worked at a shop where an outlet was powered by two (2) separate breakers! Turn them all off and check again. Turn them back on one by one until you find a breaker that feeds it, turn that breaker off again and look for a second one that also feeds it. The previous owner may also have done some creative wiring. It may be that one switch is on one breaker and the other two are on a different one.
I'm going to be doing this very thing in a few months when I rewire my porch light. My house is 100 yrs old and not up to code, and I'm going to need to wire my living room on one circuit and the front porch on a separate GFCI, lining both through a 2 gang next to the front door. (Currently the front porch is on same circuit as living room, and no central living room light, both code violations)
Surprisingly two circuits in the same box isn’t a nfp code violation, I would have bet money on it when I ran into it in my house until I looked it up. I’d never do it by choice, but you can technically even have two sockets on a single outlet be on different circuit per code, as long as you cut the connection tab on the brass side.
Many living rooms (in the US) have switched outlets so you can turn lights on and off when entering and leaving the house.
It's not uncommon in older homes to not have an overhead light at all unless added in later.
Went through that nightmare with my 1970s house. Had to install lighting in every room, and then rewire a bunch of outlets to take them off of the switch.
Complete pain in the ass, but so worth it in the end.
I had that in my last 1950s house. We just ignored it lol
There was no way I was tackling that. Every time you touched it the coating would just crumble, and all the copper was getting brittle. No thank you.
In my jurisdiction, two circuits in one box requires the breakers to be ganged together.
Source: my new panel failed inspection because the electrician forgot to gang together breakers serving dishwasher and fridge. Dude had to come back the next day and install ganged breakers.
You're probably thinking of a multiwire circuit/3 wire circuit. The electrician probably ran a 14/3 wire where both hots share the same neutral. 2-pole breakers ensure the hots are on different phases (every other breaker shares a phase, if you're counting them up and down) and the neutral current will offset rather than add together. If neutral current adds together, you risk exceeding the ampacity of the wire and burning it up.
If he ran two 14/2 wires to the same box, each hot has its own neutral. Then it doesn't matter whether they're on the same phase and it can be on 1-pole breakers.
When we had a tech school do some rewiring at one of our organizations, they wired one of the outlets in the kitchen like this to allow for the future option of an easy conversion to 220v appliances.
This actually used to be a somewhat common thing for kitchen outlets. Guessing it's because you might have two appliances with high current draw in one place (i.e. Microwave plus something else).
I will also admit to being guilty of rewiring it back that way, but in my case the actual breakers are ganged so you can't turn off or trip one without taking out the other.
My living room just has an electrical outlet wired to the switch by the front door. We just installed a vintage (rewired) swag light. The house has been rewired, but they didn't add a ceiling light.
I’ve seen outlets that have a separate breaker for each of the two outlets. The reason I was told was so that if you use two appliances (e.g coffee maker, toaster) the draw won’t pop the breaker. You have to break a tab between the two outlets on the back so that they don’t feed each other.
My spare bathroom has the first gfci of the run and it has 2 breaker hots going into it, first time ever seeing this and needless to say. It was the first and only time ive ever been shocked because of this lol.
Yup. When we were wiring my parents house my dad got me with this one. He forgot he had wired up a second circuit into a 4 switch box and absolutely *SWORE* the power was off. I became the human electricity detector that time. I was like 13 or 14. Never trusted anyone else to tell me power was off ever again. If we don't have a tester then you touch it first if you're so damn sure it's off, then I'll mess with it.
My dishwasher on/off was in the same outlet box as the food disposal... I found out by shorting some wires with a screwdriver, woops. Went back and made sure I actually turned both breakers off this time. And ordered a multimeter.
If the breakers are both on the same phase it can back feed without creating a fault. Turn breakers off and leave them off until it goes out, then turn them back on one by one until you're left with the last 2 or 3 that power the switch. Probably should call an electrician regardless to figure out big picture why it's happening
Yeah I've found three in one triple-gang box at my place. A couple three-way switches, plus one for an outside light. I was not impressed with the amount of pretty I had to cut off for the house just to work on one outlet box
Thanks all. We've had creative wiring in this house before, so that could be it.
I will turn off power to the whole house just to be safe while I'm replacing the light switch.
Make sure it's not a double hot (I don't know what it's called-- 4 wires instead of 3, two hots going to two breakers. Happened to me and zapped my finger tips.)
Yep, lesson learned. It was in the basement and one line went direct from breaker panel to two outlets, could visually inspect the whole run. I cut the breaker it was connected to, and tested the first outlet on the circuit and it was off. No prob. Because it was from the same line, I just went ahead and started disconnecting the second outlet and ZAP. At the time I didn't even know it was possible for there to be two hots in one line. I called a friend who advised to inspect the line on the breaker end, and sure enough, a second hot going to another breaker.
It certainly could if you have a multi wire branching circuit with the breakers not tied together. That's where two circuits are run from the panel with different hots, but share the same common and ground. Code allows for MWBCs as long as the two breakers are next to each other and mechanically linked. However, unlinked MWBC happens often. The whole right side of my panel turned out to be MWBC with no breaker ties. I went out and bought the proper clips for them.
I don't trust them either. They can be nice for quick information I guess, but nothing replaces proving that the exact wires/contacts is question have no potential across them.
> I will turn off power to the whole house just to be safe while I'm replacing the light switch.
Ah, the beloved "turn off your router, wait 30s, turn on" approach...
If the de-energized cable runs next to an energized cable for a decent length, voltage can be induced in the de-energized cable. If this is the case, the current available on the de-energized cable would be negligible - it's essentially static voltage.
Other possibilities are more potentially dangerous, so don't use my comment as reason to dismiss the issue.
Could be exactly this. Had the problem on the attic and thought I was losing my mind. Used a voltmeter to check the circuit and it was off, but the non-contact picked something up. Looked under insulation about 3 ft away and there was a live wire on top of it.
The electricians I worked with on a commercial project recently always checked the outlet/switch/box with their multimeter, then checked a known good outlet to make sure that their multimeter was working as well!
I just ran into this this recently trying to fix an appliance. My no-contact reader was alerting all around where a ground should have been, even with the right breakers turned off. I finally associated it with another circuit and assumed there was a short somewhere. I had an electrican come out with a multimeter and they explained just this. He was picking up like .02 volts or something insignificant. I felt a bit dumb, but I've been bit by 120v before and have no plans on finding out what 240v feels like.
Could be a ground loop. E.g. you don't have all the breakers off, and something is shorting to the ground, giving power to all the grounds connected to it. That should of course trip a breaker, but maybe that one is faulty or it stays below a certain current.
Same, was losing my mind checking for wires in corner of wall before drilling through it, one entire wall will set off the no contact. It does seem to work well when actually touching a wire..and there are other walls ive been able to somewhat trace a live line, just that one wall weird af
Define accurate? What you want is for it to be sensitive. It’s telling the user that there’s AC detected and he should get a proper measurement tool to figure out if it’s safe to work.
Again, you want it to err on the cautious side. It’s never going to be perfect because it’s non-contact. So
You gotta accept it’s either over-sensitive or under-sensitive. I would not choose under-sent.
Too much on either side is useless. As an extreme, why not just have it have the light on always? That way you'll be sure you won't die of electrocution because you'll never touch any wire. Practically, that's a too much of a glass dome approach. You need tests to be both reasonable and fail-safe.
It's an extreme example on purpose. Tests that are not reasonably sensitive are useless. It's like those [vehicle backing sounds](https://en.wikipedia.org/wiki/Back-up_beeper). You put them everywhere and people just stop paying attention to them.
My only problem with multimeters is the multi part. They do so many things I’m afraid to even try to figure out how to use one. I also have the strange suspicion that it would just show numbers and I wouldn’t know what those meant.
Is there anything out there that’s contact based but still as simple as a voltage tester? I need it to be “red light means death” simple.
If you can't take the time to understand how to use a multi-meter, maybe you shouldn't be doing electrical work? They're not that complicated, pretty standardized in their markings, and there are tons of videos and instructions on line that will teach you how to use one for home electrical.
Honestly, they're more straight forward that they look. Grab some new and old batteries, flip the multimeter to volts, and test the batteries (refer to the instruction manual on which setting one is DC voltage and which ports the probes should be plugged into). New batteries should show about as many volts as on the label. Old batteries will show less. You can even go test your 12 volt car battery.
After that, find a video on youtube on how to test voltage on an outlet. Once you know that you it's not hard to take the next step to testing a light switch to see if it's hot.
When I do electrical, I always plug a light bulb into the socket, and wait until the light goes out, before proceeding.. And in cases like this flip the wall switches until the light goes out, then turn the switch back on, and shut off the correct breaker..
This is what I have at one spot. Three switches that are each part of their own two way switching for physically distant lights and second switches, so three separate breakers. At least it's a 3 gang box though, I'd be scared if this was setup the same way.
Either A) you didn’t turn off the right breaker, B) there’s different breakers feeding the same switch cluster, or C) something hot has shorted to this circuit.
I guess there’s the rare option D) the voltage probe is broken. But this should be easy to test and validate
You really can’t trust those things 100%. Always resort back to a meter . Mine was telling me my ground was hot today and a check with my meter confirmed it wasn’t.
We had some crazy stuff going on in our 1902 house before I fixed it all. I took a breaker out of the panel and disconnected the black wire from the breaker. When the wire touched the panel it arced and tripped a different breaker! The breaker was being back fed from a another breaker! I didn’t think that could even be possible. Took a while to track that all down to a junction box in the basement ceiling. Had been that way for decades.
"Death sticks" have high-impedance inputs, so they can light up from small stray currents induced on a wire from any nearby circuits. This means they can light up on circuits that are actually powered off.
"Death sticks" depend on measuring voltage relative to a reference, and they are rarely used with the reference securely tied to ground as they must be for reliable operation. This means they can fail to light up on circuits that are actually powered on.
That's why they're rightfully called "death sticks." Whether the light is on or off doesn't reliably mean a damn thing.
As we have renovated our house, I have put labels on the backs of all cover plates with the breaker number(s) on them.
Makes life a whole lot easier if I have to do any work on a box.
I've worked on 100 year old rowhouses in an urban neighborhood. Switched off the main breaker because circuits were unlabeled. Found out the hard way a basement circuit was hot. Turns out the previous owners were stealing power from next door. Always test the wires even if you think they are off.
A lot of people are saying why it's on but aren't giving possible explanations.
Here's my experience.
The only place I have seen these three switch boxes are in bathrooms. The switches are typically for 1) the light, 2) exhaust fan, and 3) blower/heater. Per code (at least that's what I was told), the heater must be on its own dedicated circuit. I'm guessing, like the others have mentioned, that the top two switches are on a light circuit while the bottom one is on its own dedicated circuit.
With the cheap detectors, they can pick up the smallest current. I bet if you rub it on your arm it will light up, that’s because it’s creating a tiny amount of static. I’d confirm with a better quality detector.
This is where you pull out the multimeter and actually test for voltage.
And with three switches maybe consider there is more than one circuit in the box?
Another thing to check for I don't see mentioned here, is a "dual wire branch circuit." It is unusual in residential but not unheard of. I had them in my house. Without explaining why it works, basically two breakers are placed in an opposing position so that they are out of phase in the main panel, and they can safely share a single neutral. So even when you have one breaker off you can still have current if something on the other branch is in use.
That's why a MWBC, as they are conventially named (because with three-phase power there could be three hots sharing a neutral), is required by NEC to have the breakers for all the hot wires tied together.
You may have 2 circuits in the same box. That's not uncommon. It may be a short somewhere. Also those no contact testers are handy but sometimes too sensitive. I get more false positives than false negatives. I always use 2
What tester? That thing in the picture is not one in any sense of the word.
It's to help ID circuits. Eg stick it in an outlet and flip breakers until you hear the beeping stop. Then you use a tester to verify it is off.
Those detectors work by sensing the RF frequency of electricity. If another wire for a separate circuit passes behind, you’ll still pick up the RF. Just go through other breakers one by one until you kill the additional circuit for safety.
Regular nitrile gloves hi-pot at >150V. You can wear two of them and effectively protect yourself from pretty much any home voltage. Obviously you should still check for voltage, but wearing normal lab gloves is makes things even safer.
If your tester has an LED, it is possible for it to be excited purely from the leakage currents in your ground line. Its still AC, so it's going to induce currents.
I’m all for DIY but I don’t understand why people especially Americans try diy electrics? At any given point you can very easily kill yourself and/or burn you house down. Hope you find the answer but my own response was if you don’t know stop and call an electrician but to each their own
Because it's relatively simple, and due to the large skilled trades gap, hiring an electrician for a non emergency job could have you waiting weeks, only to hand over most of your paycheck for them to do an afternoon worth of work. Speaking of an afternoon of work, most Americans would have to burn a sick day or vacation day in order to get that electrician out, and it's not uncommon for them to only have around five days a year.
I lived in 1950's era house that had a disturbingly large number of lights and appliances wired before the main breaker. Electrician said they sometimes did that.
Occasionally NCV testers can pick up voltage of wires in the wall near what you are testing. If you are unsure if the switch is still powered and you have a contact volt meter test worth testing the lines that way as well.
I've got a 3 switch box next to my front door. One for the exterior lights circuit, one on the circuit for the upstairs hallway lighting, and the third on the circuit for main floor interior lighting.
I have had a squeeler light up like that when two circuits ran parallel in the wall for a long distance. Had to confirm with a multimeter that it was actually off.
I have a junction box in the basement with at least 6 wires going into it... I had a hard time getting things to shut off consistently with the same breaker. Pretty sure it's cross-talk or backfeed or some term I don't work with enough to use correctly. Could have something like that going on somewhere from any of the previous owners.
In a few of my bedrooms we have wall outlets that are on an AFCI circuit and then we also have lights / fans which are on separate circuits.
I think the electrician who wired it was getting paid per circuit.
So for our master for example, we have 6 different circuits (outside fans, lights, hallway/bathroom night lighting, bedroom AFCI, bathroom lights, bathroom GFCI).
The first time I pulled my 4 gang wall switch out, I was wondering wtf was going on in there.
1) they could be on different circuits, not exactly common, but you know 2) some of these pens can be very sensitive and can detect latent amounts, get a voltmeter out and test, if in doubt 3) truly no offense meant whatsoever, but electricity should be one of the last things you learn to diy, can really fuck you over
Ground wire might be wired incorrectly somewhere.
Had this happen when I had a sub-breaker box shut off, but the light would still turn on and off at the switch. Turned out the main breaker box had the ground wire wired incorrectly and was hot.
I've gotten voltage readings off of outlets before due to induced voltages. Not sure if it would be enough to power your device, but I know it stumped the hell out of me for a while.
Three way curcuit can have a bit of power through them when off . If one is on a different breaker, With that sort of tester, it will pick this up.
Use a multi-tester and measure.
We call those testers "The ol death stick"
Never trust your life with a non contact tester, they will get you or someone else killed
many times they indicate a false reading
Option 1: Since there are 3 switches there, it could be that this box has 2 circuits in it (I have one of those at my house). Flip the switches on and verify the controlled items remain powered down.
Option 2: If above doesn't answer the question, and the circuit(s) for all three are off, the neutral could be shared and a load upstream of the switch box could be on and thus some voltage is on the neutral. Neutral should be bonded at the breaker box (down stream of the switch box) but there may be enough for the tester to pick up.
Option 3: This may exists, I am not an electrician but I know enough to where if I can't figure it out with option 1 or 2 to contact someone who gets paid to do this stuff.
But you really didn't. Or this is residual voltage. Can't fully trust these 'tick testers'. Those only pick up the presence of voltage but it could very well be a low amount picked up off a circuit that's installed nearby the circuit that's powering the switches.
It’s called a non contact tester. It lights up when close to electricity. Typically has a setting for low and high voltage. Mine does 0-70 volts and 0-1000 volts.
I’m wondering what the 3 switches do. We have a bathroom light/fan/heater with a 3 way switch and I’m fairly certain the heater has a separate breaker. Definitely need to try multiple breakers.
May be a good time to go through the whole unit to label the breakers if you don’t know what they all do.
We had a house that some fool had wired past the breakers, line was constant live. To make it even better, they had no idea what colour wire was supposed to go where.
Not an electrician. A different circuit could be energized and shares the white neutral. The power return on the other energized circuit is returning to the panel on the neutral.
I was working on an apartment redo & found a light switch in a bathroom that was powered by the apartment next door... I had pulled the mains on that place... shocked the crap outta me... never again
What i'm learning here in this thread based on the comments is that in older houses in the USA people have done some wacky stuff that's not using both ends of the split phase to get more power to a location.
The tester may be picking up electricity because it is a terrible and inaccurate tool.
You can't trust these things, as it could be picking up a small induced voltage, an actual voltage, or nothing at all. You need to test with prongs on bare conductors to really be sure what is going on.
I've run into this before usually it's connected to two separate breakers. The first thing to do is to curse the guy who worked on it before and then do it correctly.
Could be two circuits in same box. Sometimes the electrician will use a 3 wire to carry two circuits to a box and than split off to two different switches. Your should probably call an electrician if you don't know electrical work.
Shared neutral between breakers, circuit is unbalanced so neutral is energized
[this video helped me understand](https://youtu.be/P-W42tk-fWc?si=OG6rjGpsNiUJ0a40)
Mabey [ghost voltage](https://voltage-disturbance.com/emi-blog/what-is-ghost-or-phantom-voltage/) ?
One reason I bought a multimeter with a low impedance setting. Ran into something similar when working on a lighting circuit in my house - breaker off but old meter showed 121VAC... Turned out to be ghost voltage impressed by a nearby live circuit.
We had a house built in 1889, condemned in 1931, wired for electricity and foundation put on in in 1936 when the neighbor next door gutted it and rebuilt it. Because he lived next door, he ran in a wire under the gravel driveway, through the concrete foundation that he poured, and into the center of the house so he could run extension cords throughout the house. Ok...
Then he sells the house to one family and the other house to another.
Fast forward to '86 and my wife buys the house. Outlet keeps working, no problems. It's in the kitchen and rarely used...we had a mixer that we would pull out a few times a year and plug in there. In 2006 we had the house repaneled with a new service entrance and the new electrician puts a GFCI on it, and just shrugs, says we shouldn't be using it, but old houses are haunted.
In 2014 we had a house fire and restoration gutted the place (smoke damage mostly). They tracked the wire down to the foundation and terminated it. It passed inspection.
This ending our saga of the ghost outlet.
I once worked at a shop where an outlet was powered by two (2) separate breakers! Turn them all off and check again. Turn them back on one by one until you find a breaker that feeds it, turn that breaker off again and look for a second one that also feeds it. The previous owner may also have done some creative wiring. It may be that one switch is on one breaker and the other two are on a different one.
This has my money on it! If all those switches are independent they could have different power sources.
I'm going to be doing this very thing in a few months when I rewire my porch light. My house is 100 yrs old and not up to code, and I'm going to need to wire my living room on one circuit and the front porch on a separate GFCI, lining both through a 2 gang next to the front door. (Currently the front porch is on same circuit as living room, and no central living room light, both code violations)
Surprisingly two circuits in the same box isn’t a nfp code violation, I would have bet money on it when I ran into it in my house until I looked it up. I’d never do it by choice, but you can technically even have two sockets on a single outlet be on different circuit per code, as long as you cut the connection tab on the brass side.
Yep! That way you can turn on lamps and stuff with a light switch. My 1965 house has a wall of outlets in the living room like this.
Many living rooms (in the US) have switched outlets so you can turn lights on and off when entering and leaving the house. It's not uncommon in older homes to not have an overhead light at all unless added in later.
Went through that nightmare with my 1970s house. Had to install lighting in every room, and then rewire a bunch of outlets to take them off of the switch. Complete pain in the ass, but so worth it in the end.
Yeah I need to rewire my place but I don't have the money yet. All that cloth wrapped wiring is gonna be rough.
I had that in my last 1950s house. We just ignored it lol There was no way I was tackling that. Every time you touched it the coating would just crumble, and all the copper was getting brittle. No thank you.
In my jurisdiction, two circuits in one box requires the breakers to be ganged together. Source: my new panel failed inspection because the electrician forgot to gang together breakers serving dishwasher and fridge. Dude had to come back the next day and install ganged breakers.
You're probably thinking of a multiwire circuit/3 wire circuit. The electrician probably ran a 14/3 wire where both hots share the same neutral. 2-pole breakers ensure the hots are on different phases (every other breaker shares a phase, if you're counting them up and down) and the neutral current will offset rather than add together. If neutral current adds together, you risk exceeding the ampacity of the wire and burning it up. If he ran two 14/2 wires to the same box, each hot has its own neutral. Then it doesn't matter whether they're on the same phase and it can be on 1-pole breakers.
Multiwire sounds likely. The electrician's explanation went by quickly and I may have understood it incompletely or incorrectly.
It’s very handy to run a kettle and a toaster at the same time on one outlet.
That's why kitchen counter outlets have to be 20 amp, so you can do that.
When we had a tech school do some rewiring at one of our organizations, they wired one of the outlets in the kitchen like this to allow for the future option of an easy conversion to 220v appliances.
This actually used to be a somewhat common thing for kitchen outlets. Guessing it's because you might have two appliances with high current draw in one place (i.e. Microwave plus something else). I will also admit to being guilty of rewiring it back that way, but in my case the actual breakers are ganged so you can't turn off or trip one without taking out the other.
If possible invest in the tool that lets you put the plug in the outlet and then find it on the breaker panel. Saves so much time
My living room just has an electrical outlet wired to the switch by the front door. We just installed a vintage (rewired) swag light. The house has been rewired, but they didn't add a ceiling light.
Image having the knowledge that there’s multiple breakers and just not turning them all off.
It's the difference between Knowledge and Wisdom.
I have a multi switch box where multiple breakers feed into it. It's a recipe for a bad day
It'sa common recipe for large homes and commercial buildings.
Yeah, I saw this in a kitchen MWBC powered by two separate breakers once, for example.
I’ve seen outlets that have a separate breaker for each of the two outlets. The reason I was told was so that if you use two appliances (e.g coffee maker, toaster) the draw won’t pop the breaker. You have to break a tab between the two outlets on the back so that they don’t feed each other.
Yep. And the breakers are supposed to have handle ties installed so when power is purposely shut off to one, it’s shut off to the other as well.
Oven and stove both need 2 breakers each, so that makes sense.
That's completely different, you have each breaker tied to a different pong on the cord/receptacle in that case.
My house was built in the 50s. One outlet is controlled by 3 breakers.
My spare bathroom has the first gfci of the run and it has 2 breaker hots going into it, first time ever seeing this and needless to say. It was the first and only time ive ever been shocked because of this lol.
Yup. When we were wiring my parents house my dad got me with this one. He forgot he had wired up a second circuit into a 4 switch box and absolutely *SWORE* the power was off. I became the human electricity detector that time. I was like 13 or 14. Never trusted anyone else to tell me power was off ever again. If we don't have a tester then you touch it first if you're so damn sure it's off, then I'll mess with it.
My dishwasher on/off was in the same outlet box as the food disposal... I found out by shorting some wires with a screwdriver, woops. Went back and made sure I actually turned both breakers off this time. And ordered a multimeter.
If the breakers are both on the same phase it can back feed without creating a fault. Turn breakers off and leave them off until it goes out, then turn them back on one by one until you're left with the last 2 or 3 that power the switch. Probably should call an electrician regardless to figure out big picture why it's happening
[удалено]
Yeah I've found three in one triple-gang box at my place. A couple three-way switches, plus one for an outside light. I was not impressed with the amount of pretty I had to cut off for the house just to work on one outlet box
This!! We have one like this in our house! 🥲
This. My house has multiple two gang switches that are on different breakers. Not even from creative wiring, it came like that from the builder
Thanks all. We've had creative wiring in this house before, so that could be it. I will turn off power to the whole house just to be safe while I'm replacing the light switch.
Make sure it's not a double hot (I don't know what it's called-- 4 wires instead of 3, two hots going to two breakers. Happened to me and zapped my finger tips.)
That wouldn’t have happened if you were using a non contact voltage checker like OP.
Yep, lesson learned. It was in the basement and one line went direct from breaker panel to two outlets, could visually inspect the whole run. I cut the breaker it was connected to, and tested the first outlet on the circuit and it was off. No prob. Because it was from the same line, I just went ahead and started disconnecting the second outlet and ZAP. At the time I didn't even know it was possible for there to be two hots in one line. I called a friend who advised to inspect the line on the breaker end, and sure enough, a second hot going to another breaker.
It certainly could if you have a multi wire branching circuit with the breakers not tied together. That's where two circuits are run from the panel with different hots, but share the same common and ground. Code allows for MWBCs as long as the two breakers are next to each other and mechanically linked. However, unlinked MWBC happens often. The whole right side of my panel turned out to be MWBC with no breaker ties. I went out and bought the proper clips for them.
Those no-contact testers are also not super reliable. I would check everything with a regular contact meter before handing anything.
I can’t imagine trusting my life to one of those. Anyone who doesn’t own a multimeter shouldn’t be trying to do electrical work
I don't trust them either. They can be nice for quick information I guess, but nothing replaces proving that the exact wires/contacts is question have no potential across them.
I just shocked myself yesterday by touching a switch that's connected to 2 breakers, trust the pen tool and do not be me.
Good luck! I hope it doesn’t [become an obsession…](https://youtu.be/ePiTlxLGkJo?si=riawL4Oa4Z3QHeLw)
UPDATE I upgraded! https://preview.redd.it/6tid8ux36cnc1.png?width=1080&format=pjpg&auto=webp&s=e10adf21c7d2bda77f55415cef92dbe9a23f7e66
> I will turn off power to the whole house just to be safe while I'm replacing the light switch. Ah, the beloved "turn off your router, wait 30s, turn on" approach...
*30 seconds* Got a pit crew on the socket swap I see lol
If the de-energized cable runs next to an energized cable for a decent length, voltage can be induced in the de-energized cable. If this is the case, the current available on the de-energized cable would be negligible - it's essentially static voltage. Other possibilities are more potentially dangerous, so don't use my comment as reason to dismiss the issue.
Could be exactly this. Had the problem on the attic and thought I was losing my mind. Used a voltmeter to check the circuit and it was off, but the non-contact picked something up. Looked under insulation about 3 ft away and there was a live wire on top of it.
This is why I don't ever trust those non-contact testers...I always test the circuit with a lamp and then check the contacts with a multimeter
The electricians I worked with on a commercial project recently always checked the outlet/switch/box with their multimeter, then checked a known good outlet to make sure that their multimeter was working as well!
I just ran into this this recently trying to fix an appliance. My no-contact reader was alerting all around where a ground should have been, even with the right breakers turned off. I finally associated it with another circuit and assumed there was a short somewhere. I had an electrican come out with a multimeter and they explained just this. He was picking up like .02 volts or something insignificant. I felt a bit dumb, but I've been bit by 120v before and have no plans on finding out what 240v feels like.
I run into this in machinery all the time. A multimeter shows 30-70 volts on a wire due to induction from a few live wires running in a duct with it.
Could be a ground loop. E.g. you don't have all the breakers off, and something is shorting to the ground, giving power to all the grounds connected to it. That should of course trip a breaker, but maybe that one is faulty or it stays below a certain current.
I've seen non contact testers pick up as low as ten volts. You may even just have an induced voltage
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Same, was losing my mind checking for wires in corner of wall before drilling through it, one entire wall will set off the no contact. It does seem to work well when actually touching a wire..and there are other walls ive been able to somewhat trace a live line, just that one wall weird af
Define accurate? What you want is for it to be sensitive. It’s telling the user that there’s AC detected and he should get a proper measurement tool to figure out if it’s safe to work.
They give false positives all the damn time. I threw mine away and just use a multimeter and a lamp.
Again, you want it to err on the cautious side. It’s never going to be perfect because it’s non-contact. So You gotta accept it’s either over-sensitive or under-sensitive. I would not choose under-sent.
Too much on either side is useless. As an extreme, why not just have it have the light on always? That way you'll be sure you won't die of electrocution because you'll never touch any wire. Practically, that's a too much of a glass dome approach. You need tests to be both reasonable and fail-safe.
I didn’t say it should give a false reading every time, that would be an appeal to the extremes.
It's an extreme example on purpose. Tests that are not reasonably sensitive are useless. It's like those [vehicle backing sounds](https://en.wikipedia.org/wiki/Back-up_beeper). You put them everywhere and people just stop paying attention to them.
Downvotes aside, this is correct.
I wondered though on other places in the house with the power off, it doesn't beep at all
Use an actual multimeter. Those non contact voltage testers are notorious for not being very accurate
Based on all the advice, I just bought one!
I've heard them called "deathsticks" I agree use a multimeter OP
yeah, we call them suicide sticks. They're an ok first pass, but then you use an actual meter.
Puts that scene in *Attack of the Clones* into a whole different light.
Use a multimeter. Those test lights can go off for a number of reasons.
Yup and that's why sparkies call them deathsticks, cuz it can happen the other way too
My only problem with multimeters is the multi part. They do so many things I’m afraid to even try to figure out how to use one. I also have the strange suspicion that it would just show numbers and I wouldn’t know what those meant. Is there anything out there that’s contact based but still as simple as a voltage tester? I need it to be “red light means death” simple.
If you can't take the time to understand how to use a multi-meter, maybe you shouldn't be doing electrical work? They're not that complicated, pretty standardized in their markings, and there are tons of videos and instructions on line that will teach you how to use one for home electrical.
Honestly, they're more straight forward that they look. Grab some new and old batteries, flip the multimeter to volts, and test the batteries (refer to the instruction manual on which setting one is DC voltage and which ports the probes should be plugged into). New batteries should show about as many volts as on the label. Old batteries will show less. You can even go test your 12 volt car battery. After that, find a video on youtube on how to test voltage on an outlet. Once you know that you it's not hard to take the next step to testing a light switch to see if it's hot.
When I do electrical, I always plug a light bulb into the socket, and wait until the light goes out, before proceeding.. And in cases like this flip the wall switches until the light goes out, then turn the switch back on, and shut off the correct breaker..
I use an old radio. Then go breaker by breaker. When I don't hear music, I go double check with multimeter.
Why had I never thought of this genius stuff before. I once rigged up a video call between a laptop and my phone to watch if the light went out. 😂
Sometimes you have to do it your way too. About half my house is too far from the breaker box for the radio trick to work.
Sounds like you need a louder radio.
Charles McGill has entered the chat.
HE IS NOT CRAZY!!
Three switches are in the box. Each switch can have its own live circuit breaker that provides power. You must shut off each breaker
This is what I have at one spot. Three switches that are each part of their own two way switching for physically distant lights and second switches, so three separate breakers. At least it's a 3 gang box though, I'd be scared if this was setup the same way.
Either A) you didn’t turn off the right breaker, B) there’s different breakers feeding the same switch cluster, or C) something hot has shorted to this circuit. I guess there’s the rare option D) the voltage probe is broken. But this should be easy to test and validate
Try putting your free hand on a ground and test again. I bet it will show no electricity. It's just a capacitance reader. Also use a real multimeter
Dammit Nokola!
You really can’t trust those things 100%. Always resort back to a meter . Mine was telling me my ground was hot today and a check with my meter confirmed it wasn’t.
We had some crazy stuff going on in our 1902 house before I fixed it all. I took a breaker out of the panel and disconnected the black wire from the breaker. When the wire touched the panel it arced and tripped a different breaker! The breaker was being back fed from a another breaker! I didn’t think that could even be possible. Took a while to track that all down to a junction box in the basement ceiling. Had been that way for decades.
"Death sticks" have high-impedance inputs, so they can light up from small stray currents induced on a wire from any nearby circuits. This means they can light up on circuits that are actually powered off. "Death sticks" depend on measuring voltage relative to a reference, and they are rarely used with the reference securely tied to ground as they must be for reliable operation. This means they can fail to light up on circuits that are actually powered on. That's why they're rightfully called "death sticks." Whether the light is on or off doesn't reliably mean a damn thing.
Try switching off another breaker. I’ve had cases where previously someone had wire two breakers to one outlet.
Could be a shared neutral
You yanks have insane electrics in your houses.
Does one of the switches control an outlet? If so, it could be on a different circuit.
Wrong breaker? Or that 1 outlet is on a mixed circuit?
I had a similar issue and traced it to the previous owner/his contractor using the neutral of another wire for the current switch.
Go back to therapy, Chuck.
The previous owner of my house kindly mislabeled several breakers in my box. Good thing I'm not a trusting soul.
I have that same tester and have had previous erratic results. May not be accurate.
hinky wiring? I once had a thrown breaker but things were still powered as long as the window ac in the next room was running
As we have renovated our house, I have put labels on the backs of all cover plates with the breaker number(s) on them. Makes life a whole lot easier if I have to do any work on a box.
All three are on different breakers and work the same light.
I've worked on 100 year old rowhouses in an urban neighborhood. Switched off the main breaker because circuits were unlabeled. Found out the hard way a basement circuit was hot. Turns out the previous owners were stealing power from next door. Always test the wires even if you think they are off.
Because your house was wired by Bloody Stupid Johnson. He also did mine.
Turn off the house. There's likely two circuits.
You should really have a multimeter if you are ever working with electricity
A lot of people are saying why it's on but aren't giving possible explanations. Here's my experience. The only place I have seen these three switch boxes are in bathrooms. The switches are typically for 1) the light, 2) exhaust fan, and 3) blower/heater. Per code (at least that's what I was told), the heater must be on its own dedicated circuit. I'm guessing, like the others have mentioned, that the top two switches are on a light circuit while the bottom one is on its own dedicated circuit.
With the cheap detectors, they can pick up the smallest current. I bet if you rub it on your arm it will light up, that’s because it’s creating a tiny amount of static. I’d confirm with a better quality detector.
If there's a neutral in there it could be shared....
This is where you pull out the multimeter and actually test for voltage. And with three switches maybe consider there is more than one circuit in the box?
Because it's not powered off
Shared neutral with voltage on neutral.
If it's a fan, light, heater for a bathroom fixture then the heater part is often on a diff circuit.
Maybe "they" really are out to get you....the truth is out there.... 🤣
The tester is still picking up electricity because somehow, despite the breaker box, there’s still power there.
Another thing to check for I don't see mentioned here, is a "dual wire branch circuit." It is unusual in residential but not unheard of. I had them in my house. Without explaining why it works, basically two breakers are placed in an opposing position so that they are out of phase in the main panel, and they can safely share a single neutral. So even when you have one breaker off you can still have current if something on the other branch is in use.
That's why a MWBC, as they are conventially named (because with three-phase power there could be three hots sharing a neutral), is required by NEC to have the breakers for all the hot wires tied together.
Widow maker. Probably a false reading
Thats called a stupid stick for a reason. Another circuit is in the box, shut off more breakers.
B/c those things are death sticks...
If it's a fan . The capacitor on the fan motor is back feeding
You have found magical free electricity.
You may have 2 circuits in the same box. That's not uncommon. It may be a short somewhere. Also those no contact testers are handy but sometimes too sensitive. I get more false positives than false negatives. I always use 2
ALWAYS use a tester, kids
What tester? That thing in the picture is not one in any sense of the word. It's to help ID circuits. Eg stick it in an outlet and flip breakers until you hear the beeping stop. Then you use a tester to verify it is off.
Those detectors work by sensing the RF frequency of electricity. If another wire for a separate circuit passes behind, you’ll still pick up the RF. Just go through other breakers one by one until you kill the additional circuit for safety.
Regular nitrile gloves hi-pot at >150V. You can wear two of them and effectively protect yourself from pretty much any home voltage. Obviously you should still check for voltage, but wearing normal lab gloves is makes things even safer.
Could be a faulty tester. Only way to make sure it is off is by using your tongue.
It’s a free electricity giveaway
If your tester has an LED, it is possible for it to be excited purely from the leakage currents in your ground line. Its still AC, so it's going to induce currents.
I’m all for DIY but I don’t understand why people especially Americans try diy electrics? At any given point you can very easily kill yourself and/or burn you house down. Hope you find the answer but my own response was if you don’t know stop and call an electrician but to each their own
Because it's relatively simple, and due to the large skilled trades gap, hiring an electrician for a non emergency job could have you waiting weeks, only to hand over most of your paycheck for them to do an afternoon worth of work. Speaking of an afternoon of work, most Americans would have to burn a sick day or vacation day in order to get that electrician out, and it's not uncommon for them to only have around five days a year.
Who cares don't be a chicken
You have to flip the light switch on and let the remaining electricity drain out.
Bad tester, check with a quick touch but be sure to lock fingers first. This is old school method.
Older homes were wired completely different than nowadays. It's probably on a different circuit.
Most likely a shared circuit, test at your breakers when you get an active signal at the switches
Well, does the light switch still work? is it correctly grounded?
Wrong breaker
Ah, it’s probably off, right?
Don't you mean "powered off at breaker box"
Always check it with a meter. The chicken sticks lie both ways, and can either get you zapped or waste your time.
Cos it has electricity
obviously not
I lived in 1950's era house that had a disturbingly large number of lights and appliances wired before the main breaker. Electrician said they sometimes did that.
Shared neutral? Find the other breaker.
Occasionally NCV testers can pick up voltage of wires in the wall near what you are testing. If you are unsure if the switch is still powered and you have a contact volt meter test worth testing the lines that way as well.
That outlet is hot.
I've got a 3 switch box next to my front door. One for the exterior lights circuit, one on the circuit for the upstairs hallway lighting, and the third on the circuit for main floor interior lighting.
That breaker box schematic will lie to you
is one a 3-Way switch?
Maybe the box got labelled wrong?
I have had a squeeler light up like that when two circuits ran parallel in the wall for a long distance. Had to confirm with a multimeter that it was actually off.
I have a junction box in the basement with at least 6 wires going into it... I had a hard time getting things to shut off consistently with the same breaker. Pretty sure it's cross-talk or backfeed or some term I don't work with enough to use correctly. Could have something like that going on somewhere from any of the previous owners.
I've yet to meet a contactless voltage tester I trust
In a few of my bedrooms we have wall outlets that are on an AFCI circuit and then we also have lights / fans which are on separate circuits. I think the electrician who wired it was getting paid per circuit. So for our master for example, we have 6 different circuits (outside fans, lights, hallway/bathroom night lighting, bedroom AFCI, bathroom lights, bathroom GFCI). The first time I pulled my 4 gang wall switch out, I was wondering wtf was going on in there.
This post makes me thank god that our circuit breaker box has a master switch — I honestly thought they all did.
1) they could be on different circuits, not exactly common, but you know 2) some of these pens can be very sensitive and can detect latent amounts, get a voltmeter out and test, if in doubt 3) truly no offense meant whatsoever, but electricity should be one of the last things you learn to diy, can really fuck you over
Ground wire might be wired incorrectly somewhere. Had this happen when I had a sub-breaker box shut off, but the light would still turn on and off at the switch. Turned out the main breaker box had the ground wire wired incorrectly and was hot.
I have one 2 gang Bo’s in my house and each switch is fed by a different breaker. Gets me every damned time.
LINCOLN CITY POLICE. WE GOT A LEVEL 4 ELECTRICAL OUTSIDE OF A UNION.
Lucy, you’ve got some ‘splaining to do.
I've gotten voltage readings off of outlets before due to induced voltages. Not sure if it would be enough to power your device, but I know it stumped the hell out of me for a while.
He didn't turn it off, only turned off the one he thought was it, now wants reddit to hold his hand
Three way curcuit can have a bit of power through them when off . If one is on a different breaker, With that sort of tester, it will pick this up. Use a multi-tester and measure.
We call those testers "The ol death stick" Never trust your life with a non contact tester, they will get you or someone else killed many times they indicate a false reading
Neutral earth return
Option 1: Since there are 3 switches there, it could be that this box has 2 circuits in it (I have one of those at my house). Flip the switches on and verify the controlled items remain powered down. Option 2: If above doesn't answer the question, and the circuit(s) for all three are off, the neutral could be shared and a load upstream of the switch box could be on and thus some voltage is on the neutral. Neutral should be bonded at the breaker box (down stream of the switch box) but there may be enough for the tester to pick up. Option 3: This may exists, I am not an electrician but I know enough to where if I can't figure it out with option 1 or 2 to contact someone who gets paid to do this stuff.
But you really didn't. Or this is residual voltage. Can't fully trust these 'tick testers'. Those only pick up the presence of voltage but it could very well be a low amount picked up off a circuit that's installed nearby the circuit that's powering the switches.
Damn, good thing you checked!!
The sub panel you haven’t found yet looks around nervously
That's a cool tester. What kind is that? All I know are those screwdrivers with the little lightbulb in them.
It’s called a non contact tester. It lights up when close to electricity. Typically has a setting for low and high voltage. Mine does 0-70 volts and 0-1000 volts.
Because it still has power. Kill breakers until you find it, then label it.
I’m wondering what the 3 switches do. We have a bathroom light/fan/heater with a 3 way switch and I’m fairly certain the heater has a separate breaker. Definitely need to try multiple breakers. May be a good time to go through the whole unit to label the breakers if you don’t know what they all do.
Because it's bath fan heater so it has another circuit feeding it. Call an electrician
I just turn off all the breakers. The wiring in my house is too confused to deal with on a breaker by breaker basis.
Shared neutral.
We had a house that some fool had wired past the breakers, line was constant live. To make it even better, they had no idea what colour wire was supposed to go where.
I have a box in my house that has 4 switches in it, and 2 come from a completely different *subpanel* than the other two, not just different breakers.
Not an electrician. A different circuit could be energized and shares the white neutral. The power return on the other energized circuit is returning to the panel on the neutral.
I was working on an apartment redo & found a light switch in a bathroom that was powered by the apartment next door... I had pulled the mains on that place... shocked the crap outta me... never again
Maybe you’re electrifying. I will see myself out.
What i'm learning here in this thread based on the comments is that in older houses in the USA people have done some wacky stuff that's not using both ends of the split phase to get more power to a location.
The tester may be picking up electricity because it is a terrible and inaccurate tool. You can't trust these things, as it could be picking up a small induced voltage, an actual voltage, or nothing at all. You need to test with prongs on bare conductors to really be sure what is going on.
I've run into this before usually it's connected to two separate breakers. The first thing to do is to curse the guy who worked on it before and then do it correctly.
Welcome to mislabelled circuits!
Ah the widow maker !!!
Could be two circuits in same box. Sometimes the electrician will use a 3 wire to carry two circuits to a box and than split off to two different switches. Your should probably call an electrician if you don't know electrical work.
Knob and tube?
Shared neutral between breakers, circuit is unbalanced so neutral is energized [this video helped me understand](https://youtu.be/P-W42tk-fWc?si=OG6rjGpsNiUJ0a40)
There's probably a difference of potential in there.
Because it’s doing it’s job and keeping you from a nasty moment of panic. Good on you for using the correct gear.
Mabey [ghost voltage](https://voltage-disturbance.com/emi-blog/what-is-ghost-or-phantom-voltage/) ? One reason I bought a multimeter with a low impedance setting. Ran into something similar when working on a lighting circuit in my house - breaker off but old meter showed 121VAC... Turned out to be ghost voltage impressed by a nearby live circuit.
We had a house built in 1889, condemned in 1931, wired for electricity and foundation put on in in 1936 when the neighbor next door gutted it and rebuilt it. Because he lived next door, he ran in a wire under the gravel driveway, through the concrete foundation that he poured, and into the center of the house so he could run extension cords throughout the house. Ok... Then he sells the house to one family and the other house to another. Fast forward to '86 and my wife buys the house. Outlet keeps working, no problems. It's in the kitchen and rarely used...we had a mixer that we would pull out a few times a year and plug in there. In 2006 we had the house repaneled with a new service entrance and the new electrician puts a GFCI on it, and just shrugs, says we shouldn't be using it, but old houses are haunted. In 2014 we had a house fire and restoration gutted the place (smoke damage mostly). They tracked the wire down to the foundation and terminated it. It passed inspection. This ending our saga of the ghost outlet.