Electric Connection Issue

[norrirn]

On 2 separate occasions approximately 2 years apart, we have suffered arcing at the external electrical connection of our 2013 Thor A.C.E. 29.2. In the first instance, we were in New Mexico and discovered the issue when I had to struggle to disconnect the power cord from the coach. There had been obvious arcing and some heat distortion of the female plug. I purchased a new cord then replaced the end of the original cord. In the latest instance, we were sitting in the coach with the A/C on watching TV when all AC power failed. After checking all the usual suspects and finding no answers, I tried to remove the power cord from the coach and had to once again struggle to remove it. After successfully removing the cord, I found that there had been serious heat build up at the connection so I employed my backup power cord and went on. Once again, I have replaced the female connector on the original cord because the wire is a heavier gauge than the backup, 10gauge I think.

So now, I am snake bit; this is a 30amp connection, all interior lights are now LEDs, and, in this latest instance, the only things drawing power would have been the A/C, the TV, a few LED lights, the 12v fridge, and maybe, just maybe, the water heater. I tend to discount the WH as there had been no demand for a couple hours prior.


Is it possible that the twist lock connector is not making good contact? The hot side is where the damage has occurred on both cases. There is only slight discolorization on the male connector on the coach implying that whatever occurs is going on is on the female, cord, side. Could there be a problem on the coach connection?


Thoughts, comments please.

[Bob_C]

I'd be check'n the buss bar connections....

[windsorbill]

Originally Posted by norrirn

On 2 separate occasions approximately 2 years apart, we have suffered arcing at the external electrical connection of our 2013 Thor A.C.E. 29.2. In the first instance, we were in New Mexico and discovered the issue when I had to struggle to disconnect the power cord from the coach. There had been obvious arcing and some heat distortion of the female plug. I purchased a new cord then replaced the end of the original cord. In the latest instance, we were sitting in the coach with the A/C on watching TV when all AC power failed. After checking all the usual suspects and finding no answers, I tried to remove the power cord from the coach and had to once again struggle to remove it. After successfully removing the cord, I found that there had been serious heat build up at the connection so I employed my backup power cord and went on. Once again, I have replaced the female connector on the original cord because the wire is a heavier gauge than the backup, 10gauge I think.

So now, I am snake bit; this is a 30amp connection, all interior lights are now LEDs, and, in this latest instance, the only things drawing power would have been the A/C, the TV, a few LED lights, the 12v fridge, and maybe, just maybe, the water heater. I tend to discount the WH as there had been no demand for a couple hours prior.


Is it possible that the twist lock connector is not making good contact? The hot side is where the damage has occurred on both cases. There is only slight discolorization on the male connector on the coach implying that whatever occurs is going on is on the female, cord, side. Could there be a problem on the coach connection?


Thoughts, comments please.

Not real familiar with the Thor ACE, but I would check all connections in the circuit breaker box. Check transfer switch too, if you have one. A loose connection will cause a big increase in power draw.

be sure all power is off before you test anything.

[sedaliaterry]

windsorbill is spot on, definitely check the Transfer Switch wire lugs for correct torque. See other recent reference here.

Also you may want to review this reference.

[Rkesselus]

Originally Posted by windsorbill

Not real familiar with the Thor ACE, but I would check all connections in the circuit breaker box. Check transfer switch too, if you have one. A loose connection will cause a big increase in power draw.

be sure all power is off before you test anything.

I would think you need to have the power on if you are going to test some thing in the circuit. I would have the power disconnected to look for possible problems as stated. I know nit picking but who knows what one might do?

[jerichorick]

Originally Posted by norrirn

On 2 separate occasions approximately 2 years apart, we have suffered arcing at the external electrical connection of our 2013 Thor A.C.E. 29.2. In the first instance, we were in New Mexico and discovered the issue when I had to struggle to disconnect the power cord from the coach. There had been obvious arcing and some heat distortion of the female plug. I purchased a new cord then replaced the end of the original cord. In the latest instance, we were sitting in the coach with the A/C on watching TV when all AC power failed. After checking all the usual suspects and finding no answers, I tried to remove the power cord from the coach and had to once again struggle to remove it. After successfully removing the cord, I found that there had been serious heat build up at the connection so I employed my backup power cord and went on. Once again, I have replaced the female connector on the original cord because the wire is a heavier gauge than the backup, 10gauge I think.

So now, I am snake bit; this is a 30amp connection, all interior lights are now LEDs, and, in this latest instance, the only things drawing power would have been the A/C, the TV, a few LED lights, the 12v fridge, and maybe, just maybe, the water heater. I tend to discount the WH as there had been no demand for a couple hours prior.


Is it possible that the twist lock connector is not making good contact? The hot side is where the damage has occurred on both cases. There is only slight discolorization on the male connector on the coach implying that whatever occurs is going on is on the female, cord, side. Could there be a problem on the coach connection?


Thoughts, comments please.

Seeing that the failure is in the same place I would start there. Look behind the connector mounted on the coach. I would replace it in any case. (https://www.amazon.com/EPICORD-EXRV0...p+rv+connector) Make certain that the connections there are tight when you put the new connector on. Use a bit of no-ox compound such as this - https://www.homedepot.com/p/Ideal-NO...-026/202276208 sparingly on the contacts of your plugs prongs and even on the connections. Check ALL of the connections in your ATS and service panel for tightness. ALWAYS work on these with the power off, breaker off on the generator and the inverter turned off. After the service is complete, power everything back up and run your normal loads as usual. Buy an inexpensive IR thermometer. (https://www.amazon.com/Etekcity-Lase...rmometer&psc=1) Test all of your connections for heat buildup after a reasonable time in usage. Correct when found.


Please, all, use care when doing these routines. All of us should go through our connections once in a while. The first time should be shortly after purchasing your rig.

[windsorbill]

Originally Posted by Rkesselus

I would think you need to have the power on if you are going to test some thing in the circuit. I would have the power disconnected to look for possible problems as stated. I know nit picking but who knows what one might do?

When I said test, I should have been more clear. I was referring to checking to be sure all lugs/connections are snug. My bad.

I don't have a clue about the electrical knowledge of the OP. If he's knowledgeable, then he'll/she'll know. If not, better safe than sorry.

I've seen some posts that people don't know the difference between AC and DC voltage. Kinda scary when they start opening up electrical panels.

[norrirn]

I greatly appreciate the feedback. Replacing the coachside male connector box has been on my radar but since there appeared to be no damage there I had discounted it. I wasn't considering a possible loose connection behind it. Replacing the box is a fairly simple task which would seem to have no downside so I'll do that.


I am reasonably familiar with things electrical including the difference between AC and DC current, 12v and 120 volt circuits. My knowledge extends to the level of when to go no further and call in the experts.

I'll post my results once all is complete. Thank you all again!

[Mudfrog]

The OP stated that the heat and burning is at the twist lock connection. That's going to be where the problem is. The female twist lock was burnt so there's no doubt the male that's mounted in the wall needs checking and probably replacing.