Burnt wires in power distribution panel

[BeeBee]

While tracing the cause of an intermittent electrical failure in an electrical circuit in our ORV 21RBS, I discovered that all of the neutral wires in the power distribution panel were 'burnt" where they attached to the block. I pulled the wire for the problem circuit, cleaned it, reattached it and the problem was solved(fridge now works on AC). I am wondering if a power surge might have been the cause of the burnt wires. We did stay at a few campgrounds this past summer with power hookups. Any thoughts on possible causes? I am thinking about getting a surge protector after this incident, even though we mostly dry camp. Below is a link to a pic of the wires in question (well, I hope there is a link below, as I am new to this).


Click For Full-Size Image.

[dougrainer]

MY rule when working on 120 volt Breaker boxes and Transfer switches, is, I tighten the screws as tight as I can get them. WAIT 30 minutes and then tighten again. Even solid core wire will "settle" a little. Stranded wire will settle a lot more. You will be surprised that you will usually get 1/2 to full turn on the screws after initial tightening. Doug

PS, the cause of neutral burning is the MAIN Neutral supply was loose and caused a heat build up and that heat build up caused the BUSS bar to heat up and expand slightly and then all Neutral wires then heated up and melted or burnt loose. ANOTHER cause is, in conjunction with loose wires, running on overloaded CG circuits that drop the line voltage. BOTH together will cause a problem, that is why it is important to tighten the wires in the Breaker box. Once done, it should not be needed again.

[BB_TX]

BeeBee wrote:
QCMan - thanks for that comment. It had not crossed my mind as a possible cause. Think I will pull and the wires, clean them, and reattach to the block. Might avert a future problem.

Not only the neutral wires but all the wiring in your load center, hot, neutral, ground, and also all the wire terminations on the 12 volt fuse panel.

Something that should be done on new RVs and periodically on older ones. Many of my wires were not properly tightened when new. A not uncommon problem.

[enblethen]

If the wire is really hard to bend, you may need to cut it back to get good clean copper. You should be able to feel the difference from over-heated wire and good wire. Clean wire good if discolored with steel wool.

[BeeBee]

Thanks to everyone. I'll clean the corrosion from the buss barr and wires and coat with electrical grease as suggested.

[wa8yxm]

QCMan wrote:
Odds are they are all loose or were before you tightened them. Loose connections = higher resistance = high temps = burnt wires.

I will second that. I'm fond of sayinig many RVers have a few screws loose.. in fact those very screws are what I am talking about.

One of mine took over 3 FULL TURNS to tighten. I don't think they even tried at the factory.

[enblethen]

Transfer switches are not common in trailers and only if equipped with on-board gensets.
I would suggest coating the wires with electrical grease. The buss bars are commonly aluminum which oxidizes causing issues. de-oxidation compound lessen this.

[dedmiston]

BeeBee wrote:
Thanks all for the replies. Is an "ATS" the "transfer switch" ? Is that the switch that switches from DC to AC? Where might I find that in my travel trailer?

Mine makes an audible "bump" about 20 seconds after we start the gen. My wife asks me when it's OK to run the microwave, and I always tell her to listen for the thump. She always looks at me like I'm nuts, but I'll hear it and then point as some of the devices come on (like the electric fireplace).

If you listen quietly, this thump should help you find yours.

[BeeBee]

Thanks all for the replies. Is an "ATS" the "transfer switch" ? Is that the switch that switches from DC to AC? Where might I find that in my travel trailer?

[phillyg]

I found similar in the main panel and transfer switch in my old Bounder. It was also a rats nest of extra wire. I must have taken out three feet of excessive wire in bits and pieces, and it all needed tightening. Amazing there was no fire.

[wolfe10]

Yup, tightening all the screws in ATS and main 120 VAC distribution panel are part of a routine annual maintenance!

[2oldman]

Road vibration does this, over time. Amazing what it can do given enough time. I'm always finding little screws on the floor.

[BeeBee]

QCMan - thanks for that comment. It had not crossed my mind as a possible cause. Think I will pull and the wires, clean them, and reattach to the block. Might avert a future problem.

[wolfe10]

QCMan wrote:
Odds are they are all loose or were before you tightened them. Loose connections = higher resistance = high temps = burnt wires.

I agree. MUCH more likely that a random power surge causing the excessive heat that destroyed the insulation on all of them.

[QCMan]

Odds are they are all loose or were before you tightened them. Loose connections = higher resistance = high temps = burnt wires.