Troubleshooting mystery three way switch

[GirlnAgarage]

I have to troubleshoot a three way light switch. Problem is, I have no clue 1) what fixture or outlet it is suppose to control, and 2) the other switch it works with.

How do I track this down?


The reason I need to solve this is because this switch, when turned on sends power to another circuit when that breaker is turned off

I have a guess of which outlet and what switch it MIGHT work with but I need to confirm and fix.

 

[nehog]

The reason I need to solve this is because this switch, when turned on sends power to another circuit when that breaker is turned off
...

That's a big WOW... Remember that thread about the guy with the 'buried' splice that overheated? You probably have a similar situation.

Were this mine, I'd want to visually trace that circuit out, something is clearly very 'wrong' there and should be addressed. (You know that, of course!)

 

[930dreamer]

This should be good, hope you find it quickly.

 

[GirlnAgarage]

Nehog, I do remember that. Matter of fact I saw that thread last night when I searched GJ. "That could go rally bad" came to mind.

Did a little more investigating over my first cup of coffee. I believe I've confirmed the circuits, the switches and the outlet. I think these two circuits were crossed when someone miswired the double switch plate leading out to the garage.

 

[justsam]

Are the switches Decora (rocker) or regular toggle? If toggle, the two switches that control the light will not have an ON or OFF embossed on them. Note this is not foolproof since a 3 way switch can always be used for a regular switch.

Of course the next way to determine the switch candidates is to pull them out and see which ones have three wires on them.

 

[GirlnAgarage]

Are the switches Decora (rocker) or regular toggle? If toggle, the two switches that control the light will not have an ON or OFF embossed on them. Note this is not foolproof since a 3 way switch can always be used for a regular switch.

Of course the next way to determine the switch candidates is to pull them out and see which ones have three wires on them.

Ohhhh I see what you mean looking at the switches on the outside. I did not know that. You learn something new every day! Last night I did pull the switch plate covers off both locations and saw all three switches had three screws each (2 gold, 1 black).

 

[Milton Shaw]

There should be a forth switch somewhere. That may be where the problem is. IF you had three switches with three wires at one location you should have three more switches with three wires somewhere else in the house.. They have to be paired up unless they are four way switches(four wires to switch, the two runner wires) in which case you still need to find the other switches. Just pull cover plates until you find them. Other doors into room, if for outside lights other doors out of the house. If doors were closed off and remodeled you may have switch hidden in wall. Use one of the non contact electrical testers. I have a fluke that will follow hot wires at least a foot away, not just inch away.

 

[GirlnAgarage]

There should be a forth switch somewhere. That may be where the problem is. IF you had three switches with three wires at one location you should have three more switches with three wires somewhere else in the house.. They have to be paired up unless they are four way switches(four wires to switch, the two runner wires) in which case you still need to find the other switches. Just pull cover plates until you find them. Other doors into room, if for outside lights other doors out of the house. If doors were closed off and remodeled you may have switch hidden in wall. Use one of the non contact electrical testers. I have a fluke that will follow hot wires at least a foot away, not just inch away.

Ok.

I'm not quite sure how to provide all the info here in a non-confusing manner. So, if there's a detail you need, ask me and I'll explain the best I can. I suppose I can try a draw a pic with the switches in question. I have a whole floor plan and a circuit map but they are not put together.


Edit: Put together drawing of the two circuits in question

O - outlet
L - light fixture
S - switch

The switch & outlet I'm having trouble with is on the left side of the 1/2 bath and then that double switch around the corner to the right.

Main Panel is 1-20
SubPanel 1-8

#14,16 100A breaker supplies subpanel

18B is circuit 18 bottom on the main
Sub 6 is circuit 6 on the subpanel


Scenario Confirmed --> When 18B off, Sub 6 off and 14,16 on, there is no power to either circuits, even when I flip the three way switches on.

Scenario Confirmed --> When 18B off, Sub 6 on and 14,16 off, there is no power to either circuits, even when I flip the three way switches on.

Scenario Confirmed --> When 18B off, Sub 6 on and 14,16on, there is power sent to all circuit when I flip the three way switches. This was the original scenario that caught my attention.

Scenario Confirmed --> When 18B on, Sub 6 on and 14,16 off, power is sent to the Sub 6 outlet when the three way switches are flipped.

Scenario Confirmed --> When 18B on, Sub 6 off and 14,16 off, power is sent to the Sub 6 outlet when three way switches are flipped.

Scenario Confirmed --> When 18B on, Sub 6 on and 14,16 on, power is sent to the Sub 6 outlet without any of the switches being on. EEHHHH??

 

[Aceman]

Is hiring an electrician out of the question?

 

[rvr6000]

I believe I'm in a similar situation but didn't discover it until I had an electrician come in and swap out my fuse panel for a breaker box. After he got all the wires hooked up he started turning on the breakers one by one. As he flipped one of them on there was a big spark and two breakers tripped.....turns out one of the wires he hooked up was already hot.

I haven't had a chance to get him back out to investigate it more but I suspect when the previous owner of the house replaced all the outlets in the living room he never broke the tab so half the outlet was switched and the other was always hot. There are two switches in the living room that do nothing.....seems like that's what they would be for.

 

[GirlnAgarage]

I believe I'm in a similar situation but didn't discover it until I had an electrician come in and swap out my fuse panel for a breaker box. After he got all the wires hooked up he started turning on the breakers one by one. As he flipped one of them on there was a big spark and two breakers tripped.....turns out one of the wires he hooked up was already hot.

I haven't had a chance to get him back out to investigate it more but I suspect when the previous owner of the house replaced all the outlets in the living room he never broke the tab so half the outlet was switched and the other was always hot. There are two switches in the living room that do nothing.....seems like that's what they would be for.

That sounds just like here at our house. We have two switches that seemed to do nothing. We bought this house in '09 and the POs did their "upgrades". If you've already got an electrician have him come by again since he's the most recent up to speed on your place. Some of the guys were joking with me when I mentioned the mystery switches on my wall. They said they couldn't figure out why their garage doors kept going up and down.


My problem presented itself earlier this week as I was finishing up mapping my circuits as I plan to install better lighting to the garage. I turned off the garage light circuit, checked my notes and all was good. For some reason I flipped one of the mystery switches on the wall as I walked by. I nearly peed myself when the garage circuit went live.

I used this circuit finder to map my circuits

Since I suspected an outlet was involved in this mystery three way I used the indicator plug as I confirmed this scenarios I listed above. It has been a good tool.

Yesterday I purchased a voltage detector that makes a tone. I need to identify the wires now in these two switches and outlet. It should get fun. I have not decided what I want to do with these switches and outlet yet. But I'm leaning towards completely deactivating the living room switch, put the outlet as a regular outlet, and turning the switch by the garage to the driveway light switch (which doesn't even exist right now).



I wondered if one of these would help

 

[volleyball]

Popping off the switch plate looking for 2 sets of wires at the outlet may be your quickest way. A circuit will have an in and out wire except at the end but only 1 set of wires going to the device.
I have one of those circuit tracers and you have to turn down the sensitivity a lot if you have wires running in parallel through the walls.