My Dad has a story on this one. He was a mechanical engineer in a Brisbane power station in the 50s/60s. In those days, generators had to be manually phase synchronised before being connected to the grid. You had to spin up the generator and vary its speed whilst monitoring the relative phase on a meter. Once the relative phase between the grid and generator was zero, it was safe to throw the switch to put the generator on-line. One day, someone threw the switch when the phase was 180 degrees...

The entire generator, including its concrete foundation, ripped itself out of the ground.

There was also the one about an electrician working on a generator who blasted himself with 66kV (low impedance). Massive burns, but he lived.