[George C]

Originally Posted by magnets

I've got a scary one too.

A few nights ago, I was turning down some shafts on a lathe, and the power went out. Our school has an emergency generator, which came on, but only powered a few emergency lights. To be safe, I hit the switch on the lathe, then proceeded to remove the part from the chuck to bring it to the next room. As I turned around to grab a rag, the power came back, the lathe started (with chuck key in chuck), and flung the heavy steel key 20 feet across the room and made a hole in the wall. Instead of turning off the power for the lathe, I turned off the power feed, which has the same handle and operates in the same way as the lever for power. If the power had come on a second later, the chuck key would have probably killed me.

Precisely why many jurisdictions mandate magnetic switches. Might be worth looking in to.