I have attached and filled tank. I wired heater to plug--grounds attached to proper screws. When I touch the electrical outlet box cover (metal) and copper pipe on the heater, I get shocked. The outlet has space for three wires ( 2 hot and 1 nuetral ) the wires coming to the outlet have 1 hot, 1 nuetral, and 1 ground, the hot and nuetral are attached to the receptacle, and the ground is attached to the metal box itself. What can I do to prvent this shock?

