Near-miss fire

bobnelms · 06-26-2021, 06:03 AM

Hi all,

I want to share a near-miss fire that happened the last time I was out with our 5th wheel. I pulled into the campground, hooked up the power, detached the pull vehicle and then leveled the unit.

I went inside to turn on the AC units -- there are 2 of them. The bedroom unit turned on, but the living room unit did not. I thought it was a thermostat issue, but then realized that one of our other appliances was not working either.

I checked all the fuses but none of them were tripped.

I went outside, thinking that there was a problem with the utility post that I was plugged into (50 amp), but all looked well. Then I jiggled the shore power cable where it connects to the back of the 5th wheel and BINGO, the living room AC turned on! Problem solved.

But upon leaving the campground and disconnecting the shore power, I noticed that there had been arcing at the plug -- enough to char the plug.

These TWIST AND LOCK plugs can come loose!!!! I tightened the collar as much as I could, but it still came loose.

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I wish I knew how to prevent this in the future! Any ideas?

dutchmensport · 06-26-2021, 06:23 AM

You may already be doing this, but connect the electric cord from the camper to the shore power source first. Then flip the breaker on at the shore power post. When breaking camp, flip the breaker at the shore power post first, then unplug everything. This prevents arching on our power cord connections.

rhagfo · 06-26-2021, 06:58 AM

Time to replace both sides of that connection! Wiggling a connection is not a fix, should have turned off power and disconnected and reconnected checking all blades and sockets. Both sides replaced with quality parts.

wiredgeorge · 06-26-2021, 08:32 AM

I would think an EMS might be in order. I am not an electrician but plug should have two hots, a neutral and a ground and the orientation of the holes where it connects to the camper don't look right. Am I crazy? If you have a couple A/C units, wouldn't this be a 50A service?

**sourdough** · 06-26-2021, 09:08 AM

Quote:

Originally Posted by wiredgeorge

I would think an EMS might be in order. I am not an electrician but plug should have two hots, a neutral and a ground and the orientation of the holes where it connects to the camper don't look right. Am I crazy? If you have a couple A/C units, wouldn't this be a 50A service?

https://www.etrailer.com/RV-Power-In...CABEgJp5_D_BwE

Grd. is the outer contact (4th conductor).

jasin1 · 06-26-2021, 09:39 AM

I know it saves money to just replace the ends but I like factory made cords.
It’s about $45 for both ends and a good replacement cord is $125.
In the grand scheme of things I believe there are better areas to save money.
I don’t scrimp on electrical parts.
If i have to buy a new cord every 5 years or so it’s not that big of a deal to me.
Maybe get a sacrificial dog bone adaptor for the pedestal connection so your cords last longer if you run across a loose outlet.
You also need a new connector at the trailer. And connect that one first and then connect the pedestal with the breaker off.

Any problem that includes the word “fire” deserves the best possible parts for the job.

bobnelms · 06-26-2021, 11:30 AM

Thanks, but yes, I already do this.

bobnelms · 06-26-2021, 11:34 AM

Thanks, but I'm wondering if there are not better connects than this TWIST AND LOCK. It seems that even if I replace everything NEW, the same thing might happen again. These TWIST and LOCK connectors can untwist a bit -- which I think is what happened to mine.

**sourdough** · 06-26-2021, 12:10 PM

Just curious but how does a twist lock (tightened down) "untwist" causing a loose connection? I've used them a long time and all over the place for short periods and long periods and never had that occur. Heck, I've stayed in some places I've had to dig the power cable out of the grown over grass but no one ever touches the power cable while connected and powered up - and shouldn't.

jasin1 · 06-26-2021, 12:11 PM

Quote:

Originally Posted by bobnelms

Thanks, but I'm wondering if there are not better connects than this TWIST AND LOCK. It seems that even if I replace everything NEW, the same thing might happen again. These TWIST and LOCK connectors can untwist a bit -- which I think is what happened to mine.

I would just replace and be careful with it.. you may want to look into Marinco brand plugs and cords…they are mostly for marine use and are built to use around water so are pretty tough. I also use a bungy cord to keep my cord secured to my bike rack..if I pull on the cord it won’t rip it out of the socket

**flybouy** · 06-26-2021, 12:11 PM

If you firmly and completly engage the twist lock and tighten the lock ring it shouldn't "come loose" on it's own. These electrical components are used by the tens of thousands on trailers without issue. Typical failures are from arcing fue to plugging them in "hot" as has been discussed, dirty connections, or loose wire connections where the wire is connected to the fixture. Any loose fonnecyion will cause arcing which causes heat anc a carbon coating that increases resistance. Once that happens it's a vicious circle that spirals into a ginal "meltdown".

The best prevention after ensuring that the breaker is off before connecting and disconnecting is bring observant. Look at each plug/receptical every time you use it and pay particular attention if any component feels hot or warmer than the surrounding objects. Any electrical cord that feels warm is a sign of danger. I've s÷n folks that have the sirconditioners, fridge, and water heater turn on electric and plug in to a live pedestal. That instant surge of high amperage load can wreak havoc with electrical systems. Replace the trailer receptical and the shore power cord or the end of it at a min. When replacing those componrnts it's critically important yo cut and strip the wire back far enough to get good, new looking shiney wire. If the wire is discolored by overheating then you'll have a repeated failure of the connectors.

travelin texans · 06-26-2021, 12:21 PM

A 50 amp EMS, hardwired or portable also should be on your list of electrical devices to add to any/every power source you plug your rv into.

Northofu1 · 06-26-2021, 12:58 PM

If money is no problem, no twisting here.
https://www.etrailer.com/RV-Power-In...ug/SM96FR.html

**sourdough** · 06-26-2021, 02:41 PM

Quote:

Originally Posted by Northofu1

If money is no problem, no twisting here.
https://www.etrailer.com/RV-Power-In...ug/SM96FR.html

Ouch! Think I'll just tweak that twist ring one more time...

**flybouy** · 06-26-2021, 03:29 PM

The price of those "Smart Plugs" will "smart" (as in hurt) when you go to pay for them. I think the biggest issue with twist lock is people are afraid of turning them too hard and don't get the locking rings properly secured. It's very easy to get that locking ring cross threaded and it "feels like it's tight" when in reality it's started crooked and you feel the resistance of the ctoss threading. The locking ring should spin on with little effort for a few revolutions before offering apreachiable resistance.

Northofu1 · 06-26-2021, 04:02 PM

So in theory, the smart plug is almost cheaper and less labour intensive than two cross threaded Furrions. The smart plug combo is the same Price as the new furrion plug and inlet

rhagfo · 06-26-2021, 04:09 PM

Quote:

Originally Posted by jasin1

I know it saves money to just replace the ends but I like factory made cords.
It’s about $45 for both ends and a good replacement cord is $125.
In the grand scheme of things I believe there are better areas to save money.
I don’t scrimp on electrical parts.
If i have to buy a new cord every 5 years or so it’s not that big of a deal to me.
Maybe get a sacrificial dog bone adaptor for the pedestal connection so your cords last longer if you run across a loose outlet.
You also need a new connector at the trailer. And connect that one first and then connect the pedestal with the breaker off.

Any problem that includes the word “fire” deserves the best possible parts for the job.

Well seeing how the receptical is also damaged, now you are at near $200 for new cable and receptical. I trust a connection I can visually check, plus that is only a 25’ cheap heavy plastic cord, mine is 40’ SOOW cable far more flexible and durable.

sandy43 · 06-26-2021, 04:16 PM

When using my EMS system this is what I do. Breaker off, plug EMS in pedestal, turn breaker on, let it go through it's cycle, plug 50A cord in EMS, make sure it's still reading good then plug in RV. Make sure everything is off inside and the cord is not warm. Am I doing this correctly? Opinions.

**sourdough** · 06-26-2021, 04:29 PM

IMO no. You are waiting until power is connected then plugging in each connection so they powered up and nothing to stop arcing. Connect your cable etc., plug it into the EMS, plug into the ped then flip the breaker. Power will be applies to all the secure connections when the EMS determines everything is up to snuff; no arcing/hot circuits being plugged in.

**flybouy** · 06-26-2021, 04:45 PM

If you want a visual try this. At night, enter a room in your home and plug in a vacuum cleaner. Turn on the vacuum and turn off the lights. Then, with the vacuum running and the room dark unplug the vacuum. Then while still dark plug it back in eith the switch still on.

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