3way switch trips breaker

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  #1  
Old 11-08-07, 03:57 AM
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3way switch trips breaker

I have one light fixture controlled by two switches.
Switch #1 (SW1) controls the light properly.
Switch #2 (SW2) causes the breaker to trip when turned ON.

Power comes into the fixture (on 14/2), then goes to a jct box (via 14/2), then feeds the two 3way switches (via 14/3).

On both switches, the 14/3 red wire is connected to the black terminal (common).
On both switches, the 14/3 black and white wires are connected to the other 2 gold terminals (travelers).

In the jct box:
SW1 black : SW2 black
SW1 white : SW2 white
SW1 red : Light fixture black
SW2 red : Light fixture white

At one point this all worked properly (40 yr old house).
I recently began work in the area to add more lighting. I am attempting to steal some non-switched power from the light fixture circuit to feed the new lights.

My next step is to back everything "new" out, and see if I can get back to square 1.

Anything obvious that I'm missing?

Thanks,
Steve
 
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Old 11-08-07, 04:16 AM
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You forgot to tell us how things are wired at the light. We need to know that. I suspect that you messed up the wiring at the light when you were "attempting to steal some non-switched power from the light fixture circuit to feed the new lights."

And by the way, while what you have told us about the switches will work (provided the connections at the light are proper), you do have a code violation which you should address.
 
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Old 11-08-07, 05:38 AM
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Thanks for the reply.

Power from the panel (15a breaker) runs directly to the light fixture.

In the light fixture box there was already another 14/2 going out - this is feeding a different section of the basement. So I know that it's always hot (non-switched).

For my project, I was attempting to duplicate that logic by tapping into the same non-switched hot line to feed my new lights.

Please provide more detail on the code violation so I can address it.

I guess I was just focusing on the 2 3way switches since the light worked and they seemed like the obvious culprit.

Since you've verified the connections between the switches, I'll take a better inventory of what's happening in the light fixture and reply back later.

Thanks,
Steve
 
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Old 11-08-07, 05:43 AM
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Actually, my comment was premature. You may not have a violation at the switch loop section of the circuit. It depends on the wiring. It does use a non-standard wiring convention, but that is not a code violation.
 
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Old 11-08-07, 06:14 AM
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SW1 black : SW2 black
SW1 white : SW2 white
SW1 red : Light fixture black
SW2 red : Light fixture white
This will work IF the wiring at the fixture is correct. You must have the power wire from the breaker to the white wire going to the junction box.
The black wire coming back from the junction box to the fixture is the switched wire. It gets connected to the fixture black. The fixture white gets connected to the other whites.
 

Last edited by joed; 11-08-07 at 06:18 AM. Reason: misread post
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Old 11-08-07, 06:25 AM
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joed,

I took his statement to mean that the red wires were connected to the black and white wires from the light box, not necessarily the actual wires from the light itself.

Indeed, if they were connected to the actual light wires then the light would always be on, and the breaker would trip with the switches in a certain position.

I think we need more information.


Edit: I see your correction which you posted as I was typing this post.
 
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Old 11-08-07, 07:35 AM
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On both switches, the 14/3 red wire is connected to the black terminal (common).
Wrong the red should not be connected to the common screw of both switches.

Should be like this.....

http://www.selfhelpandmore.com/switc...y/3wayfixture/
 
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Old 11-08-07, 07:59 AM
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Roger,

There are numerous ways to wire a three way setup, many legal (to code), many that work, many that don't work.

Connecting the red to the common can be just as valid and legal as connecting the black to the common.

His setup as described will work just fine and is lagel, as long as the connections at the light are valid, which joed and I suspect are not.
 
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Old 11-08-07, 08:32 AM
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IF there are 2-wire cables ONLY,, each with a Black & White wire, connected to the switch-controlled fixture out-let box , then there is ----

One "Feed-In" pair ---- one or more "Feed--Out" pairs ----and----

one "switch-loop " pair, which must be identified, and this can be done simply by wrapping black tape over the White wire. Presumimg we have "positive" indentification of the "switch-loop" pair ,and the pair now consists of two "Blacks" , any Black can connect to either the fixture-lead , or to the Black wires of the cable-pairs.

You may have to dis-connect the Black/White pair at the switch to identify the "switch-loop" pair at the fixture outlet-box.
 
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Old 11-08-07, 10:19 AM
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You posted the wrong drawing for what has been described. It is more like this one except that the fixture box is actually a junctoin box with power feed in the image being a switch loop feed from the actual fixture. The other difference is that use of the black and red wires is swapped by the user. Reds go to common not the blacks.

http://www.selfhelpandmore.com/switc...waypwfxthrufx/

 
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Old 11-08-07, 10:20 AM
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Bob I'm reading this as he has the red wire of the 14/3 between the switches connected to the common of both switches...how is that ever going to work?

Edit: Your right about the many ways to do this I was replying to how I thought he had done it, appears.... I was mistaken.
 
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Old 11-08-07, 10:23 AM
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Ok Joe I guess I misread.

How do read this?

Power comes into the fixture (on 14/2), then goes to a jct box (via 14/2), then feeds the two 3way switches (via 14/3).

Edit: Joe I see where I misunderstood....thanks.
 
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Old 11-09-07, 04:50 AM
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I got it all working last night. Thanks for the feedback.

The problem was related to the new lighting I added. I backed everything out & got the original configuration (2 switches/1 light) working again. I then proceeded to add the new lights by stealing power at the fixture jct box like I discussed in my original post.

Best news - Wife is happy

OK, here's the gory details:

I'll call the lighting fixture box - "jct box2" - since there's a lot of wires in there and it's servicing more than just the light. It does happen to be located directly above the light.

In jct box2:
(no 14/3 in here, only 14/2)
Panel power White : Light fixture White
Panel power Black : to jct box1 White
Light fixture Black : to jct box1 Black

There are 2 other 14/2 cables in jct box2 which are stealing power from the incoming Panel power line. They are just straight thru connections (White:White Black:Black), so I didn't include them above. One is for my new lighting & one is feeding another part of my basement.
This was the source of my problem. I didn't have both of them running straight thru. I've since corrected that.

(Restating some info)

In jct box1:
SW1 black : SW2 black
SW1 white : SW2 white
SW1 red : from jct box2 Black
SW2 red : from jct box2 White

On both switches, the 14/3 red wire is connected to the black terminal (common).
On both switches, the 14/3 black and white wires are connected to the other 2 gold terminals (travelers).


Again, everthing is now working properly. I justed wanted to provide follow up for some of the questions asked yesterday.
I appreciate everyone's help on this.
Electric is done - on to the next project...drywall!
 
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Old 11-09-07, 05:15 AM
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The good news: The wiring you have described is proper. It's not the way I would have wired it, but it's proper.

The bad news: You may have created an unsafe condition and a code violation. You have a large number of wires in the box above the light. You may have overfilled the box. if so, you have created a code violation and an unsafe situation. I strongly suggest that you determine the box size. The size (in cubic inches) might be imprinted inside the box. We also may be able to help if you tell us the size of the box and it's material (plastic, metal, etc.).

One final comment. I strongly suggest that you purchase and read two or three books on home wiring. Start with "Wiring Simplified". The books will tell you everything (and more than) you need to know to handle the tasks you are likely to handle. They would have told you how to wire your current job right, and they would have prevented the problem you ran into.

Remember, electricity can and does start fires and kill people. Please be safe.
 
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Old 11-09-07, 06:38 AM
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Standard circular metal jct box (4" dia x 2" deep).

There are 4 romex/rag cables meeting at this box. Plus the leads to the actual light. Doesn't really seem excessive to me.

However, I will heed to your expert advice and replace it with a 4" dia, hard plastic box that's 4" deep.

Regarding the layout of the circuit - I really didn't change anything from what's existed for the past 40 yrs.
I just tapped into one spot to feed some more lighting. I didn't modify the original layout of the 3way switches/light.

I agree - I would've wired it differently if I was starting fresh. (I've said that to myself many times as I've been remodeling my house). But pulling all new romex to the two switches would require major demo of existing finished areas. Not really feasible.

I had also considered putting in several new jct boxes to make the existing wiring terminations more logical. But since I'm going to be covering the ceiling and walls with drywall, & code requires me to make them accessible, I didn't want to have little access panels everywhere.

The other option would be to run a whole new circuit from my panel, but since my panel is already full, that's not really an option either.

My decision to tap into the existing circuit was not without thought.

Thank you for the book recommendation and I appreciate your candor.
 
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Old 11-09-07, 07:10 AM
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The extra junction box where the 14-2 and two 14-3 cables meet is what is unusual. I cannot speculate on why it was done. I know that I would not have used it, instead I would have run cable directly to one or both of the the switch boxes. Each and every splice is a potential failure point. A junction box may be overlooked and may confuse someone when looking for a failure point. However, a junction box (as long as it is permanently accessible and not over-filled) is code legal.

I suspect that your box is over filled. It's hard to say for sure without knowing the capacity of the box, but I would not leave it the way it is. I would install the larger box.

Believe me, I know the problems of adding to existing circuits in older houses. I have an older house and have several circuits that have more on them than would be done today. I even have a junction box accessible from the back of a closet because it was the best way to hide it but still have it code legal.
 
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Old 11-09-07, 02:53 PM
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i just have to ask on question ... what floor is this light on... second ... do you have an attic.. the reason electricians do this three way wiring method is 1.. accesibility if it is an addition to a house and 2 less material which means a lower bill in the end.. this way is perfectly logicial and does not over fill the box...
 
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