I got nipped while working on my truck the other day. I was wiring up the trailer light relays for the towing hitch, had the switched wiring right through plus the ground on the coil, and just dabbed the wire from the other coil terminal onto the battery to check that the relay was working.

I wasn't thinking when I had the bare end of the wire in my hand as I took it off the battery and was leaning on the chassis with my arm at the same time.

O.K., the bite from the back-e.m.f. of a relay coil's field collapsing isn't going to do much harm, but it made me jump and I felt rather foolish at getting even a tiny zap from something I've known about since I was at least 10 years old! [Linked Image]