I have hooked up and unhooked in the ran many times, Never been shocked except for when... Well later paragraph to explain that.
Procedure: Take down: Turn off breaker, Pull plug, Close door, store cord
Set up,,, Open door MAKE SURE BREAKER IS OFF plug in, Turn on breaker.
Always plug in and unplug to a dead outlet.
The other paragraph:
Trailer I had the prior owner made his own adapter from an extension cord.. he hoooked the black wires to teh sliver screws and the white wires to the copper screws on both the extension cord outlet and the adapter's outlet.. IF you use HIS extension cord, all was good, but if I used my high quality 12ga, the result was a trailer with polarity reversal.. That's the only time I got shocked. And I thought *I* was color blind (Black and white I can tell apart).