Need help troubleshooting circuit in my RV

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  #1  
Old 06-08-11, 06:48 PM
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Need help troubleshooting circuit in my RV

We camp in the summer in an '82 RV which has been parked in the same campground for most of its life. But this is not an RV question...

The first day we stayed there this season, I tripped a circuit breaker inside AND outside (needed campground worker to fix). It was fine for several hours and then we went to bed. Woke up in the morning to no power. Same problem. Left that circuit off the rest of the weekend.

Over the course of the next few weeks, I've been tripping the breaker several times a day and troubleshooting the circuit in between doing everything else. Please bear with me here, as I want to make sure I give enough relevant information:

Hot wire comes out of panel into a ceiling box w/ light in the hallway. Coming out of this box are another line going to the bathroom exhaust fan, one line going to the switch that controls this light, and another line going into a bedroom outlet. Another line feeds out of the outlet and goes into a light switch, which then continues on to supply the bedroom light.

Now, we also have a pair of ceiling-mounted stereo speakers in the bedroom. After playing with everything for a while, I noticed that when I flip the breaker on, I can actually hear static coming through the speaker while the stereo is off. So I got really good at listening to the static to troubleshoot the problem. I wound up finally narrowing it down to the wire going from the switch to the first light fixture. I tried replacing the switch, but to no avail, so the problem is definitely in the wire.

--My current problem: There is wood paneling on the sides and some kind of plastic textured ceiling with no obvious ways of removing just one panel, so running a new line NEATLY is going to be a problem. When I removed the box that the switch was in and stuck my hand in there, I felt a lot of insulation and a staple holding the wire to a stud (or, I guess in this case, a furring strip).

--My test results:
1) When I tested the continuity of each of the white, black, and ground wires, all results were good. No signs of any short between wires.
2) I connected ONLY the black wire from the junction box to one terminal of the switch (no return) and heard the static. I then connected ONLY the WHITE wire from the hot wire in the junction box to a single terminal on the switch, and also heard the static. This confused me. Could both be bad?
3) I did, however, notice a problem when I hooked my meter from the hot wires to the ground of the box. I got continuity! I was concerned until I realized that the light switch in the bedroom was flipped on. Then I realized this might be completely normal, right? If the switch is on, technically that is "completing" the circuit, and being that the white neutral is hooked to the neutral bus bar in the panel this made sense. Even now, I wonder if it makes sense either way.

--My current problem: There is wood paneling on the sides and some kind of plastic textured ceiling with no obvious ways of removing just one panel, so running a new line NEATLY is going to be a problem. When I removed the box that the switch was in and stuck my hand in there, I felt a lot of insulation and a staple holding the wire to a stud (or, I guess in this case, a furring strip).

--My possible solutions:
(1) Try to fish new wire and maybe I'll get lucky.
(2) Chop up whatever I have to and fix it later
(3) Forget the switch and just replace the fixture with something that has a pull switch

I welcome all thoughts, especially help with #3 of the troubleshooting! Thanks in advance!
 
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  #2  
Old 06-09-11, 08:49 AM
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Originally Posted by Critical Mass View Post
'82...which has been parked in the same campground for most of its life.
Any chance some rodents could have gotten in? They love to chew up wiring in hard-to-reach areas.

heard the static.
That might or might not be related. It is normal for radio receivers to pick up static from power lines, it doesn't surprise me this effect would be more noticeable in an RV.

I hooked my meter from the hot wires to the ground of the box. I got continuity!
The meter can detect continuity through a light bulb or really most any other kind of appliance that's turned on.

(1) Try to fish new wire and maybe I'll get lucky.
Check out a product called wiremold. It is a surface mounted conduit, available in common colors, paintable, plastic or metal. It doesn't look too bad for something like this.

(3) Forget the switch and just replace the fixture with something that has a pull switch
Also a good idea. This would be a good test for a few days to make sure the problem is in the wire between the light and switch, before you bother to run the new wire. A pull chain ceramic base is like $2, so it would be a cheap trial.
 
  #3  
Old 06-11-11, 07:11 PM
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Thanks for your help!

Of course, in the woods there's always a chance for rodents. That was one of my first suspicions. However, I was mainly puzzled by the results of the tests, and why things APPEAR to work fine when I connect the light switch, even though I hear lots of the static over the speaker and then a little while later, POOF (heard over the speaker), there goes the breaker.

And did I mention that the stereo is OFF during all this? The static coming from the speaker was NOT coming from the receiver! SCARY! I originally thought it was sparking coming from one of the outlets or boxes, but then I got close to the speaker and heard it.

And yes, I've heard of the WireMold. That's also an alternative if I can't find something else we like with a pull chain, or can't fish a new wire.

So I think I know the solutions, but I'm still trying to figure out exactly what the problem is...
 
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Old 06-11-11, 07:56 PM
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Of course, in the woods there's always a chance for rodents. That was one of my first suspicions. However, I was mainly puzzled by the results of the tests, and why things APPEAR to work fine when I connect the light switch, even though I hear lots of the static over the speaker and then a little while later, POOF (heard over the speaker), there goes the breaker
That sounds like the wire was hit with a nail or something. Is the rv breaker tripping or the pedestal?
 
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Old 06-11-11, 08:17 PM
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Is the rv breaker tripping or the pedestal?
I don't know what you mean, but the main is not tripping, just the breaker for that individual circuit, if that's what you mean.

Nobody's put any nails or screws near that wire anywhere lately.
 
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Old 06-11-11, 08:49 PM
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An arcing wire or connection can absolutely be picked up in a radio. Since it happens even with the radio off, there could be an external amplifier picking it up. It could also be the breaker itself has burnt contacts, and the power arcs through it until it heats up enough to trip. Here's an idea, since arcing wire gets hot, maybe check with your local FD, see if you can make a donation to have them go through the RV with their FLIR camera. That should be able to pick up the hot spot through the wallboard
 
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