One time I had a used pickup camper that I had just purchased. When checking out the camper in my driveway, my son got a shock from the shell. I immediately disconnected the shore power and checked it out.
In the little load center, the neutral was bonded to the panel-like you would do on a service entrance. It appeared to have come from the factory that way.
The power inlet was wired backwards, the end result being the entire camper shell was hot and must have been that way from the day it left the factory floor.
