Well, first of all, make sure that the electrician who ran the new wire and outlet box did so according to code.
It sounds like it wasn't. Get those GROUND and COMMON wires appropriately fixed at the source end, and I would even put a ground stake into the ground wherever you mounted your outdoor receptacle box for the camper. A good ground is very essential for safety reasons, especially in campers of course and it looks like you have a hazardous situation if you do not have a good ground connection.
Hopefully, you haven't damaged any of your appliances or other equipment in your camper.
Once you get your source wiring fixed, I suspect your camper will be OK.