What would cause this to happen?!?

[cavie]

Originally Posted by Vortriede

The dogbone connects the extension cord to the 50 amp inlet, like so:

Attachment 307369

The power into the extension cord is 240 50 amp (2 120 volt legs). I don't use much power when parked at home. Just the fridge, inverter (to charge the batteries - which, except when I return from a boondocking trip, is just a trickle) and little else. If freezing weather is forecast, I sometimes run a small heater (1500 watts) and turn on the electric side of the water heater. The water heater can suck a bit of juice to begin with, but once it has heated the water, it doesn't take much in keeping it hot. All of these loads are nominal at any rate and should not be an issue.

I do think that the plug itself is the culprit. I think that the neutral conductor was not making solid contact with it's male counterpart. (Pictures coming.)

There should be no dogbone attached to your RV. Your RV connection requires a Locking ring Twist-lock connection. You plug in the shore power cord and turn it 1/4 inch to the right. Then you apply the rocking ring and tighten to the right to hold everything in place and tight. A dog bone if used goes on the shore power side of the cord. Not on the RV.

[cavie]

Originally Posted by Vortriede

The dogbone connects the extension cord to the 50 amp inlet, like so:

Attachment 307369

The power into the extension cord is 240 50 amp (2 120 volt legs). I don't use much power when parked at home. Just the fridge, inverter (to charge the batteries - which, except when I return from a boondocking trip, is just a trickle) and little else. If freezing weather is forecast, I sometimes run a small heater (1500 watts) and turn on the electric side of the water heater. The water heater can suck a bit of juice to begin with, but once it has heated the water, it doesn't take much in keeping it hot. All of these loads are nominal at any rate and should not be an issue.

I do think that the plug itself is the culprit. I think that the neutral conductor was not making solid contact with it's male counterpart. (Pictures coming.)

Nope, you are the culprit. You connecting things together all wrong!!!

[cavie]

Originally Posted by Vortriede

The extension cord is 50 amp. The dog bone is to adapt the 50 amp male to the 50 amp inlet on the MH.

I have already diagnosed the issue to be the neutral conductor in the female end of the extension cord which appears to have been loose. It has been replaced and as a precaution I have taped across the seam where the male and female connectors meet to keep out any moisture or other debris.

The problem is you. You are using a 50 amp extortion cord to attach to your RV. This is wrong. You need a 50 amp shore power cord. Different animal. You can add an extension cord to that if need be but the RV needs to have a shore power cord!

[puttin]

I've started to use Deoxit 5 at all my shore line connections to improve heat transfer and improve connectivity. Mike Sokol recommends it. There are many other products like it too. You can use it on trailer plugs or anywhere else. I keep it in my utility bay.

[Ray,IN]

Originally Posted by Vortriede

The extension cord is 50 amp. The dog bone is to adapt the 50 amp male to the 50 amp inlet on the MH.

I have already diagnosed the issue to be the neutral conductor in the female end of the extension cord which appears to have been loose. It has been replaced and as a precaution I have taped across the seam where the male and female connectors meet to keep out any moisture or other debris.

Glad you have everything repaired and know the cause. I misread your initial post.

[Old Scout]

Glad you "found" the problem....it is still kind of interesting though.....you see this sort of heating issue on 30 amp plugs quite often, especially in older CGs …..but not so much on 50 amp plugs.....if properly phased and load balanced, the neutral leg on a 50 amp RV circuits should have little or no return current.....safe travels....

[clifford j]

Was a field engineer for a company who manufactured switches , power plugs and connectors, have seen numerous failures shown in the OP's pictures. There's no definite way to determine why the failure occurred, defective part, abuse, heavy usage, but what is apparent temperature was the culprit. Lack of contact tension created elevated temperatures, when this happens the spring contact becomes annealed causing tension loss and failure. All contact points have temperature rise above ambient , U.L. has standards that limit that rise at rated current. Female connectors are tested with go/no go conditioning tools ,an oversize and then a standard ,once tested the standard size tool must have a specific amount of ounces of retention. That's a minimum standard, quality built products last longer.
The OP is on top of the problem, I would suggest inspecting the male contacts of the RV power inlet and determine if there's discoloration of the 'neutral ' blade. Or, pull the inlet and inspect further. Power cords unsupported hanging on connectors should be avoided.

CLIFFORD

[Wadell]

Originally Posted by Old Scout

Glad you "found" the problem....it is still kind of interesting though.....you see this sort of heating issue on 30 amp plugs quite often, especially in older CGs …..but not so much on 50 amp plugs.....if properly phased and load balanced, the neutral leg on a 50 amp RV circuits should have little or no return current.....safe travels....

The Neutral carries current. IF you are pulling 25 amps on L1 and 25 amps on L2 the Neutral will see and need to carry both of those neutral loads. IF you didn't connect the neutral, you L1 120v load would back fee into the neutral of the L2 120v load.

Another way to look at it, you turn on everything on the L1 power circuit and return that power on the neutral. say that load is 15 amps, with the amp meter on L1 or the neutral, you will read that 15 amps. You now add a 10 amp load on L2 circuit, along with the 15 amps on L1, you would have 15 amps on the L1 wire, 10 amps on the L2 wire, but 25 amps on the Neutral wire.

[ArtJoyce]

I have heard several times of a melt down when using dog bones. I was given a 50 foot 30 amp extension cord that one end melted from a dog bone conector. It always seems there was a inexpensive dog bone involved. Buy better dog bones.

[sibe]

Granted is is just sloppy chuna made adapters used in a may not perfect sequence... or loose contacts BUT I would really like to have clarification that the House plug is suppling 120 each leg to nuetral and 240 between the hot legs.. it is a some times mistake if breaker is not right or 2 singles got used or some robed peter to pay paul..

I have seen a NEW home. my workers, inspected and such,, have 4 - 2 gang 15 amp breakers because they ran out of room as a poor choice on a panel .. They ran 3 WIRE TO LIVING ROOM. Split to a window AC plug and as a 20a and the other walls as 4 recpts on the other wire.... He used an edenpure heater in place of the AC in winter.. They had a recliner with a vibrater and warmer/heat... His wife always cold. All repticles even the un used got WARM.. They are daisy chained with rear stabs (
a personal no no for me)
I looked at it, simple , red/blk on same LEG.. I swapped one leg with the kitchen counters that were wrong also... not a perfect fix but panel is what it is.. Nuetral in balance now.. he said stuff doesnt flicker now.. LOL

[Vortriede]

Originally Posted by cavie

There should be no dogbone attached to your RV. Your RV connection requires a Locking ring Twist-lock connection. You plug in the shore power cord and turn it 1/4 inch to the right. Then you apply the rocking ring and tighten to the right to hold everything in place and tight. A dog bone if used goes on the shore power side of the cord. Not on the RV.

I suppose that I shouldn't be calling it a dogbone. What it is, in fact, is an extremely short 50 amp shore power cord. It has a 50 amp male plug on one end and a 50 amp twist lock connector on the other end, just like any other 50 amp shore cord.

My extension cord is 50 feet long and I need all of it to reach from the receptacle in the garage, through a SurgeGuard, to the MH. My 50 amp shore cord is only 35 feet. If I used the shore cord rather than the "dogbone" (which, as I've stated is just a really short shore cord) I would have 85 feet of cable instead of 50 feet and exactly the same number of interfaces.

Originally Posted by cavie

The problem is you. You are using a 50 amp extortion cord to attach to your RV. This is wrong. You need a 50 amp shore power cord. Different animal. You can add an extension cord to that if need be but the RV needs to have a shore power cord!

With all due respect, I believe that I am not the problem. If you had read my posts on this thread a little more carefully, you would have ascertained what I have written just now, which I believe is compliant with your recommendations.

Have a wonderful Thanksgiving.

[richard5933]

Originally Posted by Vortriede

I suppose that I shouldn't be calling it a dogbone. What it is, in fact, is an extremely short 50 amp shore power cord. It has a 50 amp male plug on one end and a 50 amp twist lock connector on the other end, just like any other 50 amp shore cord...

Still confused why you don't want to eliminate the super-short shore power cord and just put the twist-lock connector on the longer cord - the one you're calling the extension cord. It would eliminate a potential point of failure.

[clifford j]

Votriede, I don't think your the problem, looking at the contact picture more closely my bet would be the contact had light spring pressure and or misalignment. The burn pattern is not uniform side to side and one leg has a burn mark on it's edge rather than across the entire width. When the conductor was inserted into that spring contact too much screw pressure may have spread the legs. Poor quality/ design in my judgement .

CLIFFORD

[twinboat]

Originally Posted by Wadell

The Neutral carries current. IF you are pulling 25 amps on L1 and 25 amps on L2 the Neutral will see and need to carry both of those neutral loads. IF you didn't connect the neutral, you L1 120v load would back fee into the neutral of the L2 120v load.

.

Its actually the complete opposite, if each line is carrying the same current, the neutral will carry nothing.
You wouldn't even need the neutral.

The neutral only carries the difference between L1 and L2.

One more point, explained in the link, 50amp 120/240 service is split out to 2 50 amp legs in the RV panel, with the potential of 100 amps avalable at 120 volts.

If the neutral was required to carry all of the current, it would need to be twice the size of each line.

https://www.rvtechmag.com/electrical/chapter3.php