3-way switch tripping a breaker

[bassbone52]

Got a back deck light that is left on all the time. Has a 3-way switch in the LR and another in the BR. If I were to flip the switch in the LR, the breaker will trip. If I flip the switch in the BR, the breaker won’t trip. I’ve tested both switches. Both OK. Any ideas on what the problem is??

 

[The Cobbler]

did it always do this or has it just started?
It sounds like a mistake in the wiring when a switch was replaced

 

[PCustoms]

Got a back deck light that is left on all the time. Has a 3-way switch in the LR and another in the BR. If I were to flip the switch in the LR, the breaker will trip. If I flip the switch in the BR, the breaker won’t trip. I’ve tested both switches. Both OK. Any ideas on what the problem is??

Is this a new issue?

Sounds to me like the neutral (or ground I guess) is likely wired wrong in the LR

 

[mm08822]

Is the circuit protected by a gfci or afci or standard breaker?

 

[bassbone52]

Standard breaker. 38 year old house and these switches have never been replaced.

 

[N_Jay]

Sound like one of the travelers is shorted to ground.

Double check your switches to ground. (Most people testing switches only test conductors and not grounds.)
Also check your boxes (if metal) they may hit a screw terminal.

 

[cgrutt]

It's also possible the switch failed internally and is shorting to ground when switched in one direction. Are the boxes metal or is ground connected to the back of switch?

 

[bassbone52]

Plastic boxes. I’ll check the grounds.

 

[mm08822]

A short to neutral or to grd usually blows itself clear or opens the circuit after a repeated closures on the fault. How many times has the breaker tripped b/c of this switch position?
Wondering if there is an unplanned high resistance connection somewhere. Has any work been done cutting into walls, screws, hanging pictures, cables used as clothes lines, etc?

If you have a meter you could lift the offending traveler from the 3-way and check its resistance to ground.

Also with the lifted traveler, is the fault eliminated in every possible switch position?

 

[bassbone52]

OK. This is a 4-gang switch box. There are two single pole switches with no issues. There is the 3-way for the deck light, which is my issue and the fourth switch is another 3-way which is part of a 4-way system that we don’t use anymore. I just discovered that the traveler pairs for the two 3-way switches were reversed! It’s been this way since the house was built in 1988. The tip off was the fact that both 3-ways for the deck light each had a hot wire at the same time, regardless of the position of the switches.

 

[mm08822]

OK. This is a 4-gang switch box. There are two single pole switches with no issues. There is the 3-way for the deck light, which is my issue and the fourth switch is another 3-way which is part of a 4-way system that we don’t use anymore. I just discovered that the traveler pairs for the two 3-way switches were reversed! It’s been this way since the house was built in 1988. The tip off was the fact that both 3-ways for the deck light each had a hot wire at the same time, regardless of the position of the switches.

So one was fed from a different circuit?

 

[bassbone52]

No, everything in this switch box is on the same circuit. There was a hot lead pigtailed into the LR 3-way that shouldn’t have been there. That and the backwards travelers made for a very confusing setup.

 

[mm08822]

No, everything in this switch box is on the same circuit. There was a hot lead pigtailed into the LR 3-way that shouldn’t have been there. That and the backwards travelers made for a very confusing setup.

Not seeing why it tripped the cb unless a neutral is being switched on one of the 3way set-ups.

 

[PCustoms]

Not seeing why it tripped the cb unless a neutral is being switched on one of the 3way set-ups.

Wouldn't it trip if the other 3 way box was fed from the other leg?

I'm not following reversed travelers though. I hate 3 ways

 

[mm08822]

Wouldn't it trip if the other 3 way box was fed from the other leg?

I'm not following reversed travelers though. I hate 3 ways

Yup, that was were my previous q was heading.

 

[PCustoms]

Yup, that was were my previous q was heading.

Yeah, his answer was focused on THAT box

 

[bassbone52]

Well, it was a cluster, for sure. You had to be there, but it’s all good now.

 

[wyliesdiesels]

I’ve tested both switches.

how did you test them?

 

[wyliesdiesels]

Wouldn't it trip if the other 3 way box was fed from the other leg?

per post #12 everything is on the same circuit

 

[wyliesdiesels]

Well, it was a cluster, for sure. You had to be there, but it’s all good now.

ok so what was the issue?

 

[PCustoms]

per post #12 everything is on the same circuit

Sure, we've already discussed this...

Go back and read #12, then #15 and #16. But thanks for responding