# Light Switch Keeps Tripping Breaker



## J187 (May 19, 2006)

you've got a 3way circuit, meaning you've got two switches controlling one light. The white wire is a neutral as you may have suspected. The black and red are not interchangeable though. You've got to figure which is common and which are travellers. If the power source comes into the switch you are replacing, then the common terminal of the switch, often black, would take the hot, probably black from the power source and the others, probably black and red, would go to the traveller screws. 

If the power comes into the switch you are not replacing, then the common of the switch you are will go to the light and again, the others will be the travellers. 

Its possible the switch WAS bad, and when you replaced it you mixed up the common and the travellers. 

Its also possible that the other switch was bad or both were, but first make sure you've got your wiring straight on the new switch.


EDIT - Regardless - you should make it a point to replace 3 way switches in pairs. If one goes, replace them both. 

My guess is, you mixed up the wiring. The travellers are interchangeable - but common and traveller are not. If you mix them, you have no bridge from power to load, the fuse box to the light.


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## mcvane (Mar 19, 2007)

*3 way switch?*

If this is a 3 way switch, maybe somewhere in this chain there is a hot wire touching the metal plate inside the switch (or touching another wire).

Basically, we moved into a house with a similar situation. It was a single switch though. The wiring at the light itself was a problem. A wire was touching the light fixture housing causing the breaker to shut off.

Another weird situation (since you say kitchen), is that we had a weird switch that basically was wired "ON" in both positions (I'm sure it violated code). In the 'up' position, it would turn on the light. In the 'down' position, the power to the range hood light/fan activated!

I rewired that to correct the problem. Maybe you have a weird situation like that?


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## J187 (May 19, 2006)

mcvane said:


> If this is a 3 way switch, maybe somewhere in this chain there is a hot wire touching the metal plate inside the switch (or touching another wire).
> 
> Basically, we moved into a house with a similar situation. It was a single switch though. The wiring at the light itself was a problem. A wire was touching the light fixture housing causing the breaker to shut off.
> 
> ...


 
MUCH more likely a common/traveller mix up, lets rule that out first.


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## HouseHelper (Mar 20, 2007)

A traveler/common mixup will not cause the breaker to trip, it will only screw up the switch operation... and the white wire connected to the 3-way switch is NOT a neutral.

If this started all of a sudden, with no removal of switches or fixtures, I would suspect a problem at the light fixture. Possibly insulation damage due to excess heat or a poor connection at a wirenut. Remove the fixture (breaker off), taking note of how it is connected, and look for wire damage or loose connections.


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## Stubbie (Jan 7, 2007)

J187.... please explain how a traveler mixup would trip the breaker? It might create a problem with not being able to turn the light on/ off at one location or the other but not trip a breaker. If you read the thread the tripping breaker was occuring before she changed out the 3-way.

Jackie.... You have a ground fault. You need to investigate inside each switch box and the light fixture box. Since there is only a black, red, white and ground in the 3-way box you changed.... this is the dead end three way and if you connected black to the dark colored screw and the red and white to the other two brass screws then you connected it correctly. The three way in the garage that has 3 blacks and ground cannot be correct. Please look more carefully the red and white should show up in that box also. 
Changing switches is ok but it is not going to help... you must find the box that has the grounded fault. Look for arcing or burnt wiring or anything metal that is touching a switch screw or a wire that may have come out of a wirenut. You're problem is not a traveler mix-up.

Has anyone been doing any work to the house that may have been near the switches in question?

EDIT: I see househelper has replied so this post is a little redundant. I agree though that the odds are the problem exists in the light fixture. Still 3 blacks and a ground and nothing else in the garage switch box is not correct. 

Stubbie


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## J187 (May 19, 2006)

Stubbie said:


> J187.... please explain how a traveler mixup would trip the breaker? It might create a problem with not being able to turn the light on/ off at one location or the other but not trip a breaker. If you read the thread the tripping breaker was occuring before she changed out the 3-way.
> 
> 
> Stubbie


Stubbie - 

I didn't mean to be misleading, but if you go back and reread my post you will see that nowhere did I say the mixup did cause the breaker to trip nor did I think it. I said it would account for the light no longer working at all. My thought was that it is likely the reason it stopped working alltogether was a wire mix up and that needs to be fixed before trouble shooting the short. I agree, its likely in the device being switched, but nothing will show if indeed the switches became miswired, compound problems lead to no solutions ever.


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## HouseHelper (Mar 20, 2007)

Stubbie: I suspect she has some whites tied together in that box, and while the three blacks is a bit unusual, it is possible the wires are run in conduit and that black was used for both travelers OR that they used two runs of NM leaving one white wire unused. I've also seen "electricians" run a single black wire as part of a 3-way circuit without the use of conduit.


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## J187 (May 19, 2006)

HouseHelper said:


> A traveler/common mixup will not cause the breaker to trip, it will only screw up the switch operation... and the white wire connected to the 3-way switch is NOT a neutral.
> 
> If this started all of a sudden, with no removal of switches or fixtures, I would suspect a problem at the light fixture. Possibly insulation damage due to excess heat or a poor connection at a wirenut. Remove the fixture (breaker off), taking note of how it is connected, and look for wire damage or loose connections.


I'm confused...

Why wouldn't the white wire be neutral and why would it be connected to the switch unless it was marked hot? Why do we have any reason to assume that the white wire is connect to the switch?


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## HouseHelper (Mar 20, 2007)

Duh, if is marked hot, it is NOT a neutral. The OP states that the house switch has three wires connected to it, white, red, black. The white in this case is a traveler (hot) not a neutral. It should be remarked.


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## J187 (May 19, 2006)

HouseHelper said:


> Duh, if is marked hot, it is NOT a neutral. The OP states that the house switch has three wires connected to it, white, red, black. The white in this case is a traveler (hot) not a neutral. It should be remarked.


 
I obviously didn't realize that at first, is the "duh" really necessary??


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## J187 (May 19, 2006)

Ok, so its, switch <-> light <-> switch with both the light and one of the switches in the garage. To me that sounds like it very well could be a conduit situation where insteading of running a red, black and white the person that ran it ran 3 black wires, thinking they were all switch legs anyway, especially if it was materials on hand. Not condoning it, just saying that it wouldn't surprise me all that much. 

Sounds like maybe the panel feeds the light and the reason it stopped working altogether is that when she replaced the switch she used black as the powersource whereas that was really a traveller and it should have been white?


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## Stubbie (Jan 7, 2007)

HouseHelper said:


> Stubbie: I suspect she has some whites tied together in that box, and while the three blacks is a bit unusual, it is possible the wires are run in conduit and that black was used for both travelers OR that they used two runs of NM leaving one white wire unused. I've also seen "electricians" run a single black wire as part of a 3-way circuit without the use of conduit.


Yep i would agree with that, I thought of conduit but just seemed really odd even if conduit but I agree things can be different than the way I would always envision it to be. I hadnt thought of the two runs of nm but that could certainly explain it.

J187...sorry but I still don't follow. Why would mixing up the travelers cause the light to completely not work outside of a burned out bulb. 
The op stated that the only wires in the switch box where she changed out the 3 -way only had a black, red, white and ground so no way it could be a neutral with only three wires plus grd in that box. What good is it going to do to look for a mix-up in the travelers when she has a breaker that is tripping? If she had a traveler mix-up the breaker is still going to trip because of the ground fault. Even if she wires the travelers correctly the breaker is still going to trip. So my point is telling her to look for a mix up in the travelers is not a solution to the tripping breaker and is also not a solution to a light on a three way circuit to completely stop working. The light will work...only it will not be controlled as it should be. Most likely the continual short circuiting from cycling the switches without finding the ground fault has burned a wire in half or the insulation has failed or some other short circuit probelm.

I'm not arguing with you just not understanding your troubleshooting advice. You did state that a traveler mix-up would cause the light to completely stop working, this is not true, so the op is chasing a non solution.

What I want is for the poster to clear the fault so she stops passing massive amps through her wiring.

Stubbie


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## J187 (May 19, 2006)

She said only one of her switches worked, the other tripped the breaker. What i was thinking was that if she connected the white at the switch which carried power from the panel to a traveller screw, that the light wouldn't work at all. I guess I'm mistaken. I thought the power needed to bridge between the common for switch and load in order to work at all. 

I completely understand why you want to clear the fault first, I just thought that it made sense to make sure you didn't keep compounding the problem first. Mostly I hope you to understand that I didn't state completely false information - the switch caused the trip, but rather that I went about the repair in a route that you would have advised against. I defer to you on this. Just a difference approach to the problem, your way being better than mine. I just wanted it to be clear that I didnt' intend to get the problem back to where it was, one switch tripping the breaker and leave it, I would have addressed the fault. Guess I wasn't clear. My bad.

Excuse the horrific drawing.


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## Stubbie (Jan 7, 2007)

No problem, I really dont know if we can proclaim how the 3-way is wired just yet. So lets wait for the op to return and see what she has found out. I never thought you were giving false information I wasnt seeing your logic but what I want is for her to quit toggling those switches resetting the breaker then toggling again in a ground fault situation. This is damaging on devices and the wiring. She needs to open up the electrical boxes and make sure the wiring is not burned up and find the cause of that fault. If its not in a fixture box or switch box then something is wrong in cable if its cable or indiviual wire if conduit.

Stubbie


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## J187 (May 19, 2006)

Cool. But just so I know, if that white was carrying the hot lead and was connected to a traveller then the light would still work - I was wrong there?


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## Stubbie (Jan 7, 2007)

If you took the white wire you are calling hot and switched with the black wire in your drawing. You could turn the light off at that switch but the other switch will not turn the light on as it should. You can cross the travelers themselves up as much as you want everything is fine. But when you cross a traveler with a common terminal one switch will not control the light both on and off
Stubbie


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## J187 (May 19, 2006)

aha, thanks.


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## mcvane (Mar 19, 2007)

*constructive different troubleshooting...*

I think this is great.

I'm just observing the back and forth messages between Stubbie and J187. Although each is a bit of different approach to solving the problem at hand, I think it's very good to dig deep into each one's skills to 'argue' your points.

This is the way it should be. I think both of you (and all readers) get to learn more and more from the different opinions you put forth.

Keep it up, as it really does help everyone!


In relation to the problem...I hope the original poster hasn't been freaked out by the advice and called an electrician! Let's see how they make out with the advice...


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## J187 (May 19, 2006)

mcvane said:


> I think this is great.
> 
> I'm just observing the back and forth messages between Stubbie and J187. Although each is a bit of different approach to solving the problem at hand, I think it's very good to dig deep into each one's skills to 'argue' your points.
> 
> ...


 
HAHA, I doubt it. I think if anything the thought of electricians is even scarier now! I love the fact that there are pros here willing to spend their time helping others, I just everyone is able to be constructive and pleasant in doing so. Almost everyone is here to learn.

I always find it amusing when someone posts up a message and doesn't return for a response for a long while - I know people are busy but I when I post up a problem I check every 10 minutes for help... Its just funny to me.


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## Stubbie (Jan 7, 2007)

DIY forums are not professional forums. And therefore are open to anyone who feels they can give advice whether or not they are trained tradesmen. When we get into differences of opinion on a post it can be constructive learning but I think at times it makes the op feel we don't know what we are talking about because we disagree openly.
Generally I dont have a problem with anyone and treat all with respect outside of a few exceptions. NEWS FLASH!! I'm not perfect either.

I suspect though in this thread the op has returned and read the posts & has discovered (I Hope) the problem. Understand that it is wishful thinking that we are always going to be able to explain in a logical enough manner to troubleshoot a problem from 1000 miles away and expect a person with no electrical knowledge to figure out what we say here. Having said that if we can help one person safely fix a problem or safely wire up their project then we have taught them something and they won't burn their house down. We win some and we lose some as they say.

I was strong in my opinion to J187 not out of disrespect but that we were distracting the op from her original problem. Ground faults are a serious business even if the ocpd is functioning. They can still cause a fire from continual cycling of the light switches and resetting the breaker and the arcing that results from the fault before the overcurrent device opens. Arcs are instantaneous massive heat.. thats why we have all our splices and connections in boxes to contain that heat in a non-flammable environment. However continual cycling of a ground fault without clearing it can still get the wire insulation on fire or wood shavings in the box and then it can spread outside the containment of the box. If you have ever observed a ground fault intentionally set-up in a classroom you will be surprised at the energy released. The wiring will move (actually jump) in measurable inches when the fault is passed through the wiring. The arc that results in some cases can destroy gfci's and if passed through them several times can catch them on fire. Just one example.

This thread worried me in that respect that she would keep on resetting that breaker and keep passing that fault current through the wiring. Worrying about whether she may have or may not have crossed up the travelers would only IMO cause her to keep cycling that ground fault. Until she finds the ground fault fooling with the travelers is only going to cause her to retest the 3-ways and pass that fault through the wiring hoping that the travelers were a fix. I disagreed with J187... thats all. Thing I want people to understand is that electrical isn't plumbing where something gets wet if you do it wrong. It also scares the ************ens out of me when we have unskilled people sticking their hands into electrical boxes. Most come to the diy formats to try to avoid the cost of an electrician. And the reality is they are going to fool with the wiring whether or not they visit an electrical forum. So in that regard we serve a valuable service for the safety of these people and their property with our advice.

Stubbie


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## J187 (May 19, 2006)

Stubbie said:


> DIY When we get into differences of opinion on a post it .... at times it makes the op feel we don't know what we are talking about because we disagree openly.


Although I'm sure you are right, that does happen, I don't think it should. You are far more likely to get bad advice from one flat opinion than you are from a forum where people openly disagree and discus the matter. The more than comes out in the open, the less that is left unknown and more gets clarified. That's the precise reason why I think forums work so well. In fact, I think this speaks to the point Mcvane was making.


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## jackiesmom (Apr 25, 2007)

Hello

I am back - I did read the first posts and didnt realize there were more.

I will be honest I am so confused and the thought of touching wires at the panel scares me.

I am calling an electrician because I dont want to burn down my house :yes: -

thank you for all your advice but I just cant follow it


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## J187 (May 19, 2006)

jackiesmom said:


> Hello
> 
> I am back - I did read the first posts and didnt realize there were more.
> 
> ...


 
Thats always the best idea if you can afford it. Good choice.


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