Can’t happen according to Myth-Busters.
My father remembers three school friends from back during the 1930s who when walking home from school in Los Angeles, stood on a bridge and urinated onto electric streetcars. They were accidenatlly electrocuted - all three boys died.
I don’t think it’s a myth.
Mythbusters is wrong. We had electric fences on our farm when I was young and I know I will NEVER piss on one again. OUCH!!