• TerryMac
    I recently returned from a two and a half month trip to the mid-west and almost had a disaster.

    As you can see from the attached photos, my electrical connector had an arcing problem and burnt the receptacle and plug severely. This could have easily started a fire and destroyed the whole rig.


    I had just gotten home and pulled onto my parking pad. I quickly grabbed my power cord, plugged it into the RV and my garage outlet. I turned on the AC and started unloading the RV (upper 90's in South Carolina). I took several days to unload the essentials and empty the fridge etc. My wife and I smelled an odd smell but it did not smell electrical nor really burnt. It was sort of a plastic type smell. We searched around for the source but could not pin point anything. Turned off the fridge and the AC.

    While doing the unloading, I had been prepping for cleaning my tanks, I worked on sanitizing my fresh water tank, then ran that water into my grey tank after dumping in a bunch of gel automatic dish washer detergent. (a tip to clean the sensors that I had heard but hadn't used yet). Added cleaner to my black tank and filled it also. The tanks then set for a few days to stew and I was planning to take the rig to a free dump station and see if that helped my tanks.

    When I was unhooking to go to the dump station, I noticed that I had not properly connected my twist lock connector. I had just plugged it in and did not twist it and did not secure the threaded ring.

    It was drooped down with at least a 1/4 inch gap at the top and when I gave it a pull, nothing happened. I smelled the strange odor again and immediately went and unplugged the other end of the cord.

    I took some twisting and pulling but I got the plug out (pulling the hot fitting out of the receptacle at the same time).

    I did my dump station run and replaced and repaired the wiring and used new outlets. One thing to watch is that heat travels up the conductor and will melt the inner insulation while the jacket looks good. You need to cut the wire back enough to get to good insulation or replace the wire.

    I'm speculation that the sloppy plug in job left a poor connection on the hot line and it was over-heating and arcing internally and was slowly burning the connectors (thus the funny smell).

    I have researched the arc detecting breakers to see if they would help with this problem but apparently they only protect downstream from the breaker. (I will replace my outlet circuit but that will only help at home.) With the state of most campground outlets, it will be a cold day when they have these outlets. Though I did have one park that had GFI on the main breaker, that was a first.

    Anyone have any ideas or thoughts on what to do to help with this? I though about making an exterior panel box with an arc detector that would be used like the surge protector devices (I have one but did not use it at home) But I was looking for a cleaner solution. Of course the best thing is to NEVER make a mistake!

    Arc-faults cause most electrical fires, not short circuits. My 30 amp breaker never tripped!

    Thanks and everyone be careful.
  • Ray
    Thanks for the write-up, its a good cautionary tale. My wife and I are always tuned to weird burning smells, campfire season really throws me off.

    Arcing is a tough one as loose or oxidize contacts can lead to an arc which can lay down a path of carbon making a second arc easier and so on until it makes the connection worse and a high resistant develops and that leads to a voltage drop across the connection and overheating takes place.

    Inline arcing versus arcing to ground usually isn't going trip a normal breaker as its max amperage is limited to the max amperage of the load being powered. I wonder how an arc detecting breaker works?
  • TerryMac
    When I was looking at them, I didn't see any theory of operation but I just did a quick scan. The wiring is unusual in that each circuit has hot and neutral going to the breaker and then another pig-tail going to the real neural. Lots of places in the states are starting to require them in bedrooms. Like GFI has been in bathrooms.
  • Ray
    Interesting, looks like they can also detect by a change in frequency. https://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter
  • Susan
    Thank you for the reminder to always push the plug all the way in and twist. Happy that you didn't burn your trailer up!
  • Rush and Lola
    That's why I like my smart plug. No more twisting a 1/4 inch.
  • Augie
    You may have just saved me from my lazy self. I will never not carefully engage connector and screw locking ring on to TT, never again! I've used this contact cleaner for years, it works well on expensive connectors but it is expensive...

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