Well, I don't know about "must do"....but up in Wash. State where
it gets kinda damp....I'd call it "highly recommended".

I was a Power Production Specialist for 11 years in the Air Force.
Generators and small engine equiptment. If you were working on
the other end of one of my generators....you'd want to make darn
sure I had that puppy grounded. (you might turn into a light bulb) [X(]