I remember hearing of a case here a few years ago in which an "electrician" had done some kitchen installation work -- I forget whether it was a washer, dryer, waste disposal or whatever. Somehow he managed to hook the stainless-steel sink up to the hot side of the supply (For crying out loud: How??!!
The owners reported tingles and mild shocks, he was called back twice and told them nothing was wrong. Third time was definitely not lucky, as someone touched it barefoot and was killed.
If I recall correctly he was charged with "causing death due to criminal negligence," or whatever the proper legal wording is.
Another accident which is sort-of polarity related was reported from a telecoms facility when I was with BT in about 1984. Like many big plants they had their own generators, and the control gear incorporated synchronization circuitry to allow parallel operation.
Apparently someone mis-wired a unit so that two gennies synched up 180 deg. out of phase. I understand they had to pull bits of engine out of the roof.
[This message has been edited by pauluk (edited 01-10-2002).]