Hello. I just dewinterized my trailer and went to drain the water heater after I made sure it was working and in getting a light shock from the metal around the heater on the exterior. Anyone know what's going on?
First thing, your rig has to be grounded. That is, the third prong, i.e. ground, has to be connected through the cord, and to your home outlet.
I suspect that if it was, you would have tripped a breaker or a GFCI.
Then I really suspect you don't have a good chassis ground (third wire) from your TT, through any extension cords or adapters, and into your home or site outlet. The ground has to be continuous.