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-   -   Light Switch Keeps Tripping Breaker (http://www.diychatroom.com/f18/light-switch-keeps-tripping-breaker-8012/)

jackiesmom 04-25-2007 01:52 PM

Light Switch Keeps Tripping Breaker
 
Hello
I have 2 switches for my garage light one in the garage and one in the kitchen. When we moved in both worked and now if you hit the switch in the kitchen it trips the breaker.
I replaced the switch but it didn't help and now the light doesn't work at all.
Inside the house the wires are red, white and black with a ground and in the garage there are 3 black with a ground.

When I put in the new switch I am using the black as the power source and the red and white to the other screws.

Any ideas?

J187 04-25-2007 02:16 PM

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.

mcvane 04-25-2007 02:16 PM

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?

J187 04-25-2007 02:22 PM

Quote:

Originally Posted by mcvane (Post 42287)
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?


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

HouseHelper 04-25-2007 02:51 PM

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.

Stubbie 04-25-2007 03:01 PM

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

J187 04-25-2007 03:31 PM

Quote:

Originally Posted by Stubbie (Post 42302)
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.

HouseHelper 04-25-2007 03:54 PM

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.

J187 04-25-2007 04:07 PM

Quote:

Originally Posted by HouseHelper (Post 42298)
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?

HouseHelper 04-25-2007 04:22 PM

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.

J187 04-25-2007 04:29 PM

Quote:

Originally Posted by HouseHelper (Post 42321)
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??

J187 04-25-2007 04:42 PM

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?

Stubbie 04-25-2007 05:02 PM

Quote:

Originally Posted by HouseHelper (Post 42316)
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

J187 04-25-2007 05:39 PM

1 Attachment(s)
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.

Stubbie 04-25-2007 06:13 PM

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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