Here are some pictures of a '70s vintage motorhome I was troubleshooting this afternoon.
Complaint was: the coach was plugged in, the customer kneeled down wearing a pair of shorts, and received a shock when he went to lift the outside access door to the generator.
Cover removed from the FPE box:
Location - its under the wooden cover
The plug looks fine but the ground pin is no longer connected to the conductor
Everything was actually wired correctly to the breaker box. The problem is a hot to ground short in one of the 120 receptacle circuits. Everything worked and nothing seemed to be wrong except for the shock. Because the ground circuit was not actually connected and the motorhome was sitting on rubber tires, the short to ground had no operational effect. The customer never got a shock climbing in or out because he always wears rubber soled shoes. Only when his bare knee was on the ground did he get bit. I have not located the short yet but as soon as the ground was repaired, it immediately tripped a breaker.
- Big Jim