Electrical Short Caused By Water Leak?

[Ako]

This is my first post but I have what seems like a serious problem. Although I’ve seen a lot of posts by people with water leaks, I haven’t found any on the possibility of those leaks causing an electrical failure.

I bought my 1969 Ambassador about a year ago. I began living in it right away and everything was working great for the first month. Then one day the lights flickered and a breaker tripped. The only things I had plugged in at the time were my computer and a small space heater. The heater turns on and off to maintain the temperature so I thought it had probably just overloaded the circuit when it switched on.

It happened again a week later, only that time I couldn’t get the lights to come back on by flipping the breaker. There must have been a surge the second time because the plug of my computer cord was scorched. I found an outlet cover that also appeared scorched, so I opened it up and found that the wires were completely burnt up to the plastic sheathing and disconnected from the outlet. I was worried when I saw how much of the wire was burnt before the breaker tripped. I called some local electricians, but no one was willing to look at it because it was inside a trailer. I didn’t trust working on it myself, so I just pulled an extension cord through a window and I’ve powered everything I needed off that.

About the same time I began to notice a leak in the air conditioning unit. It only dripped down into the cabin during heavy rains, and even then it dripped slowly. It seemed to be dripping straight down, so I put a bucket underneath and didn’t worry too much about it. I realize now that was a mistake.

Back when I had opened up the burnt outlet I noticed there was some moisture, but it was a thick dark fluid like used motor oil, and I thought it might have just been from the melted wire insulation. I didn’t make the connection between the electrical short and leaks until more recently.

The Airstream is on the Oregon Coast and it’s rainy again. A few days ago I opened up the outlet after some heavy rain and found that the fiberglass insulation behind the outlet box was soaked. Then I realized that some of the water leaking through the air conditioner might have ran down the inner paneling toward the outlet, or along the wire connected to the air conditioner, which I think runs directly into the burnt outlet box. Is it possible that the moisture inside of the box could have allowed the electricity to arc and burn the wires?

I frantically put a tarp over the air conditioner and I have a dehumidifier running full blast. So here is my dilemma. Do I try to remove the leaky air conditioning unit and cover up the hole, then try to salvage the remaining wires in the burnt outlet? Or is this something I shouldn’t fool around with, a sign that I need to take the whole trailer apart and spend a lot more time fixing things up and making sure all the seams are sealed? I thought eventually I would replace the wiring, but it’s not something I wanted to learn about as I go along.

I don’t need that outlet. I just need to complete the circuit so I get power to the lights and other outlets. But even with that, the problem I run into is that the wires are burnt and corroded so far back, almost into the fiberglass insulation, and there is not enough slack on wires to pull them out further and attach them together. I think I would have to remove the interior paneling and cabinets to get at the wires, which seems like a huge undertaking for the repair that needs to be made. Would it be risky to try to pull the wires out further and just make a simple connection? Is it even worth it to remove the paneling to get at the couple of wires, or should I wait and replace all of the wiring at once? There are definitely other projects I would want to accomplish if I begin taking the whole thing apart, but then it all might have to wait until the summer.

Of the things I had planned to work on, the electrical is what I know the least about and I have very little practical experience with it. I have a friend who is an electrician, but considering the larger problem of the leaks, I wanted to get someone’s advice from a vintage Airstream perspective before asking my friend about the specific electrical/wiring problem.

I would appreciate any advice. I really like my Airstream, but I don’t like the thought of being burnt to a crisp inside of it.

Thanks,
Adam

[garry]

Water leaking into an outlet will not normally create enough current leakage to burn wires. (exception salt water).

What I suspect is the outlet contacts had become corroded creating a "resistive" connection that would cause enough heat to burn the wires.

I assume one white, one black and a plain copper wire went to the outlet.

Since you don't need that outlet and you can reach the end of the wires for a temporary fix you can screw a wire nut onto the end of black and a wire nut onto the end of the white wire this will safely prevent any possibility of a short circuit or shock hazard.
Have no power to the coach when you do this.

[DaveFL]

Loose connection even without corrosion will cause heat.
Disconnect the 12v too, not likely but if you don't know the system, it might have an inverter somewear in there.

[blickcd]

Is the breaker that's tripping a GFCI? The GFCI breaker in my trailer seemed to trip at random and I checked all wiring I possibly could, finding nothing, and also looked for leaks, again finding nothing.

I replaced the breaker, which was an off the shelf item at Lowe's and all has been fine since then.

Christopher

[Jammer]

Garry's assessment is correct. It was not a power surge but rather the heat of a corroded, loose connection that led to the melted components. Also, you may have aluminum wire in your trailer, which is more prone to problems at connections.

Since the insulation is damaged in a place where you can't get to it, the wire segment will have to be either replaced or abandoned. If you can fish in new wire, possibly using the existing wire to pull it in, great. Otherwise you might be able to figure out an easier way to route the wire, or remove panels to get at it. Or perhaps you can move the outlet a few inches over, or add another outlet, so that you can have a place to get to an undamaged part of the wiring.

If you can get at enough of the wire to sleeve it with heatshrink that is another possibility. It's a judgment call to figure out whether the situation will allow that to be done safely so if you're fairly new at this you might want to have someone else look at it before you try that.

No easy answers.

[Ako]

Thank you everyone for your responses!

Garry and DaveFL: Based on the moisture I found behind the outlet, I definitely think corrosion would have been an issue. Even if the corrosion itself didn’t cause the wire to overheat, I would think it’s possible that it could have weakened the wire’s connection to the outlet and indirectly caused the burn.

Jammer: I’ll have my electrician take a look at it and see if the wires are long enough to make the connection. There is a smaller panel surrounding the outlet opening, so I might be able to just take that one off to get the length I need.

Blickcd: The breaker that was tripping was a conventional breaker located on the 120 volt panel. I had never heard of a GFCI breaker, but after looking it up I recognized them as the outlets in bathrooms with red reset buttons, and I think something like that might be a helpful addition. They seem to be more sensitive and would trip if there were any changes in the current. The addition of a GFCI might be good insurance while I’m getting the leak problems solved. The conventional breakers that tripped were in the Airstream when I got it, and after seeing the burnt wire I wondered if they might need to be replaced.

[Jammer]

One test that I run occasionally, especially when using high-current appliances like heaters for the first time on a circuit of doubtful provenance, is to plug in the heater and then measure the temperature of each outlet face on the circuit every minute or so for a few minutes.

These days I use an IR thermometer but you can also, carefully, feel the front of the outlet with your hand.

Even a slightly elevated temperature means there's trouble brewing.