Please help identify this wire

[chingon]

ok gang, back at it again.

the shore power does enter from the bottom and was wired to the top left bus lug. all the romex exiting to the right is original, and the smaller black wire connected to the neutral bus that enters from the uppermost port is stranded and as best i can tell from the DC system, as it is too small to carry any manner of load from AC.

no electric to the water heater, and the fridge was just removed as it just pooped out on both electric as well as LP functions.

the outside 120V outlet tested as normal with a 3-prong tester, but it is apparent that water has entered the outlet as the face of the outlet shows discoloration and oxidation.

when the shore power cord was disconnected from the service panel it did not trip the GFCI, however when wired to the 30 amp breaker it did trip, even when all breakers were pulled from the panel. i picked up a new panel, and breakers due to the inability to source a new 30amp breaker in the style currently found in the AS.

current plan: install new service panel with new breakers. wire new 30A shore power cord to 30A breaker in the new panel. connect existing branch feeders to new breakers...but what of the mysterious stranded black wire entering the current panel at upper right? i'll presume the white wire exiting lower right is a ground, but should i keep this connected? as the panel on the AS will function as a sub-panel of the shore's service panel shouldn't it rely on the shore power's ground system (in this case it is two ground rods as well as a cold water ground)?

[chingon]

also, i will note that i tried to wire the shore power cord to the 30A breaker and mount in the right most position - making it the main, but the bottom of the breakers have alignment pins that will only allow the 30A to be mounted in the left most position.

attached are photos of my "univolt" in hopes it might help diagnose the problem, or help identify the black wire that is thus far a bit of a mystery

[TG Twinkie]

Your Question:
as the panel on the AS will function as a sub-panel of the shore's service panel shouldn't it rely on the shore power's ground system (in this case it is two ground rods as well as a cold water ground)? Yes it will be a sub panel: therefore the neutral will not be grounded.

I would leave the small black wire disconnected at least for the time being.

When you get the new panel installed, just connect the shore power cable to it along with the white wire that we think is chassis ground for the trailer. Before you connect any of the branch circuits. Test the system to see if the GFI will hold.

Then connect one branch circuit at a time; testing the GFI as you complete each branch.

Looks like you need to upgrade the converter. I also notice a the 120 volt AC power to the converter has a white romex cable, I don't see a white romex entering the old sub panel. Does it get spliced or something?

If you still have the old refer hang on to it. We can do some testing to see if it still works.

If you haven't removed the old panel and still have the shore power wired in, connect the shore power back the way it was originally then remove the small black wire and test the shore power again. Just for drills.