My 3 year old travel trailer tried to burn itself down last night. I feel very lucky it's not worse than it is because I have 2 full 20lb propane tanks siting on the tongue that could have made things very bad. It's stored in my backyard with the battery and shore power connected at all times. My security camera detected motion in the backyard at 9:40pm and recorded some of the event that took place. I watched the video below at 1:30 in the morning when I saw I had a notification of motion in the back yard. The ground was wet because it was raining so there is glare reflecting off the concrete.


How in the world did this happen? I'm guessing the 12v charging wire inside the truck to trailer harness shorted to ground and started a fire. Why isn't there some type of failsafe or fuse to prevent this from happening?

 

That wiring overall is a mess and should be sorted out. However the wire that burned is on the same post as the trailer battery charge wire. There is no fused protection, the wires needed to have been on opposite posts.

 

That is unfortunate for sure, sorry.

I'm wondering if an EMS would have picked up on it and shut down.
We also leave trailer plugged up year around, dehumidifier running, furnace set to 40*.

Our trailer is parked 3ft from house so an unsuspecting fire could get ugly.

Who was the trailer manufacturer ?

 

Does that wire go to your breakaway switch? If so, is it possible that the cable on the switch got pulled?

 

I'm not familiar with RV wiring so I don't know what you are referring to by "needing to be on different posts"


That was my first thought as well, it sits close to the house. Mine sits about 25ft from the house but only 3 feet from a 6ft privacy fence with our vehicles parked just on the other side of that.

Trailer is a 2018 Forest River Salem Cruise Lite 263BHXL


Looking at the second picture the red wire running on the left most side is the tongue jack wire and it's possible that wire is still somewhat intact. The blue and orange wires might go to the breakaway switch I'm not sure.

I don't think the breakaway switch was active at this time. The breakaway switch got pulled accidently a year ago and I didn't realize it for a day or two. The thing that prompted me to look at the breakaway switch that time was because the fan on the converter inside the trailer was running and I knew that was not normal. I'm not familiar with how the converter operates but I assumed since the fan was running that meant it was charging the trailer battery so I started looking for something that was pulling amps from the battery. The converter fan was not running this time I know for as I was inside the trailer a few days ago doing some cleaning and organizing.

I think the problem was inside the wire cluster that goes to the 7pin connector. Come to think of it I've had some intermittent issues with faulty turn signals on this trailer the last couple camping trips. One time it was a faulty left turn signal (the info center in the truck actually gave me a warning) and the last time out I had a faulty right turn signal. I know the truck wasn't the issue because my other trailer has never given me any troubles. After wiggling the 7pin connector the turn signal faults would go away. Replacing the factory 7pin connector was on my to do list before the next camping trip.

On the last trip home after a 4 hour drive the trailer battery was almost dead and wouldn't operate the tongue jack without being connected to the truck. I associated the dead battery as an issue with the 7pin connector on the trailer and the fact that my wife left some of the 12v lights on inside the trailer on the drive home.

Knowing what I know now, I feel there was a short in the 7pin wiring cluster that was slowly getting worse until last night.

 

Take a look at the wiring. You see the fuse block? The 7 pin is on the battery hot side of the fuse and thus no fused protection.

 

Gotcha thanks for pointing that out. That wire goes to the tongue jack and I just checked, it is not fused so it should be moved like you suggest?

All wires from the 7pin go into that junction box.

 

I redid my wiring a couple of years ago. Looked almost like yours.


I cleaned up all the grounding points as well. Now i can run my A/C when plugged in at home.

 

That gray/black block with two posts is a fuse? I'll have to look for something like that on mine.

 

That looks much nicer than the factory, thanks for sharing.


I don't think that's a fuse. I checked and there is continuity between those 2 posts. I believe it's just a simple 2 post distribution block.

I have a mobile repair tech coming out Monday to fix all this mess. I will ask a lot of questions.

 

Mobile tech said point of origin was the Breakaway Controller and the pin was not pulled. It appeared to have shorted out internally at one of the forward corners. It's not common for this to melt down like it did, they had never seen this happen in 30 years of business.

The 2 post block on the frame is an auto-reset breaker. I Googled that and came up with this > https://www.digikey.com/en/products/...V-20A/11581330

 

Glad you got it resolved.

On our 4th trailer and stuff like this always worries me given the cheap labor used in Indiana and the fact they are paid according to production.

 

I don't know if this is relevant or not, but on a Solar forum I'm on there has been a lot of discussion about breakers. Apparently there are a lot of breakers rated for both AC and DC. Often, they aren't very good on the DC side. You certainly don't want to be using an AC breaker that has no rating for DC, that's really bad. Something about the arc produced by DC makes an AC breaker unsuitable. That's what I recall about why and I could be off. I bought the wrong breakers for my solar project in my trailer and had to replace them with real DC breakers. These are DIN rail breakers I'm talking about for my situation.

One of these days I will be opening up my initial distribution box (again) so that I can redo the wiring there. Right now, that box is where the 7-pin cable and the tongue battery (lead acid) come in. The output for the box is limited to the generator, tongue jack, breakaway system, trailer lights and the on-board air compressor. It doesn't feed into the big distribution panel inside the trailer which is powered by my LiFePO4 batteries. I would like to get to the point where I can remove the tongue battery.

Getting back to your wire fire, it seems obvious that the auto breaker didn't help. I wonder if a fuse, closer to the breakaway pin, would have helped. The 20 amp auto breaker was maybe too high a threshold? As I recall, four drum brakes would draw around 12 amps. Was the wire too small for the load? Shorting out within the box seems odd unless there was some corrosion? How old was the breakaway switch?

 

I would agree the breaker did nothing to help. I suppose that's because the always hot wire from the breakaway controller (the orange with black wire) connects directly to the same post of the breaker as the battery positive wire. I don't know how that breaker works but I have to assume the protection is only between the two posts.

I asked the techs why that little breaker didn't stop the meltdown and they didn't have an answer for me. Who knows maybe it's faulty?

The trailer was manufactured in June of 2017 so that breakaway controller was only 3 and a half years old. It was raining at the time of the fire so maybe that had a factor in the failure as well?





Edit: Here is a TSB from OptiFuse a manufacturer of the two post breaker on my trailer. It explains to a T what happened and why.

January 27, 2010
Hazards of Automatic Reset Circuit Breakers
Recently an OEM customer of OptiFuse had a major incidence while using an OptiFuse ACB2-PL circuit breaker in one of their buses. Due to circumstances unknown, a short-circuit developed under the dashboard of a vehicle causing an overcurrent situation...

The circuit was protected by an automatic reset circuit breaker which opened quickly when the short-circuit occurred. Unfortunately, an automatic reset circuit breaker is specifically designed to re-close the circuit once the circuit breaker has sufficiently cooled.

In this case, the circuit breaker opened and closed multiple times over the course or several minutes because the short circuit was still present and never cleared. Finally, after several minutes of cycling on and off, the contacts of the circuit breaker finally welded shut due to the heat of the present short circuit. With the circuit breaker now incapacitated, the wires underneath the dashboard eventually grew so hot that the insulation on the wire caught fire causing lots of smoke and a bit of panic from the bus riders.

This incident illustrates the need for proper component selection when designing any type of circuit protection scheme. The use of automatic reset circuit breakers are convenient for an overloaded circuit but offer little long-term protection when a short-circuit condition is present.

The problem in the above example could have been avoided if a manual reset or modified reset circuit breaker was used in place of the auto-reset breaker. This would have prevented the auto-reset breaker from cycling on and off and eventually failing.

An additional solution might have been to use a higher amperage fuse along with the automatic reset circuit breaker. A "selective coordination" analysis would allow the circuit breaker to open first and if the problem continues, the fuse is there as a back-up to provide additional circuit protection. This type of protection scheme is used in most electrical systems found in buildings and utility systems.

All circuit protective devices are simply an insurance policy against potential dangerous and/or expensive problems from occurring. If misapplied, there is no real protection being offered by the protection components and your insurance policy becomes null and void.

It is fortunate that no one was hurt in the above example. We can use the expirence to learn in order to prevent an event like this from happening again in the future.

Thanks to everyone for you continued support of OptiFuse where we continue our mission of educating and informing for the good our community.


Jim Kalb
President
OptiFuse
jimk@optifuse.com

 

I put in a set of eFans on my prior truck. The company that put together the kit included breakers just like the ones that may have been the culprit in your fire. They always seemed a bit sketchy to me. If the circuit was problem enough to trip the breaker, why would you want to turn it back on???