The converter has a ground but no case. It is surrounded by plastic. Like I said, It is a PD4560. I don't have an ex. cord long enough to reach anouther receptical.
All the plugs in the trailer test the same. It is possible to be partially open. Last year I found the wiring was done backwards and was for a couple years. As far as a shock when touching the sides, I have a few more tests I'm going to do tonight to see if it happends. Still can't figure out how my 120VAC grounds are acting as a return path for 12VDC or how I get 40VAC when the ground is removed...