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.

[CharlesinGA]

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?

Read thru the thread and saw that no one ever answered this. The ATS is a switch that allows shore power 120v to your panel and then when an onboard generator is started, it shuts the shore power off and allows the generator power to take over.

The ATS has NOTHING to do with DC 12v power.

If you have a motorhome with a generator you might have an ATS or you might simply have an outlet for the generator that you roll up the shore cord in its compartment and plug it into the generator outlet (manual transfer switch of sorts).

If you have a trailer and no onboard generator you won't have a ATS. If you have a built in generator you might or might not have an ATS or the outlet and plug setup I described above.

Charles

[Cummins12V98]

2oldman wrote:

Cummins12V98 wrote:
I HIGHLY suggest turning off the AC power and tightening EVERY electrical connection possible. This also applies to cords with twist locks and their receptacles.

Yes.. the screws that attach the 30a cable to the plug. PITA to check, but when they work loose things get hot.

Nad a neutral come loose and fall onto a hot. Caused Microwave and a couple other things to have 220V. Side effects were not good!

[2oldman]

Cummins12V98 wrote:
I HIGHLY suggest turning off the AC power and tightening EVERY electrical connection possible. This also applies to cords with twist locks and their receptacles.

Yes.. the screws that attach the 30a cable to the plug. PITA to check, but when they work loose things get hot.

[enblethen]

The one that could cause heat along the buss is the main neutral It should be the largest wire which is farthest left in photo. I would normally put this wire in the center of the buss as a personal favorite.

[DrewE]

time2roll wrote:

BeeBee wrote:



Click For Full-Size Image.

So is it possible there was one loose wire and the heat moved on the bus to discolor the other wires?

It's entirely possible. Generally when that's what has happened it's pretty clear which connection was loose as that wire is the most burnt one, and the ones adjacent are the next most toasted ones, etc.

[Cummins12V98]

I HIGHLY suggest turning off the AC power and tightening EVERY electrical connection possible. This also applies to cords with twist locks and their receptacles.

[BeeBee]

Thanks to all the members who replied on this issue. Such a wealth of knowledge and experience on this forum! I am going to go through the entire panel for loose and/or corroded wires, and will be cutting off and reattaching the burnt ends. I'll be monitoring this closely in the future to make sure it does not redevelop. Last thing we need is a fire in the trailer!

[MEXICOWANDERER]

Non accuracy due to having a keyboard the size of a Saltine cracker

[wolfe10]

wolfe10 wrote:

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.

Sorry, in my post one letter incorrect made my post on page one confusing/contradictory.

First sentence of my reply--I agreed with his conclusion (did then, still do!).

But, the "that" in the next sentence should have been "THAN", as "that" contradicts my agreeing with his statement. Thanks, fat fingers.

SO: Here is what my post should have said: "I agree. MUCH more likely THAN a random power surge causing the excessive heat that destroyed the insulation on all of them."

Again, sorry for the confusion.

[time2roll]

BeeBee wrote:



Click For Full-Size Image.

So is it possible there was one loose wire and the heat moved on the bus to discolor the other wires?

[frankwp]

wolfe10 wrote:

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.

No, a voltage spike will not cause that damage. Properly made & tightened, those connections will not overheat at current levels below the point at which the circuit breaker will open. A voltage spike sufficient to increase current for a long enough time to overheat a connection will trip the breaker long before damage will occur.

The burning there was a result of poor connection between the wires & lugs. Most probably a result of a rushed, low paid, unskilled worker not fully tightening the screws.

The remedy is to cut back the wire & reterminate. Cleaning the wire is not required unless obviously badly corroded. Copper oxide (as in lightly tarnished) is actually a decent conductor & isn't usually an issue.

[frankwp]

oops

[2oldman]

dougrainer wrote:
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.

Wiggling the wire as you tighten helps too.

[dougrainer]

enblethen wrote:
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.

IF the Trailer is prepped for a Genset, it will usually have the Transfer box. Doug