I was workin' with 277 volts rather than the more frequent 120 volts, just puttin' up a fixture.
Somewhere in between yesterday and today I managed to lose my "ticker", it's a little voltage detector that beeps loud when you put it to live voltage. Well, I wasn't sure whether or not the circuit I was workin' on was hot. I had seen someone touch the hot (black wire), to the neutral (white) as means to see if it was hot.
Looking back, they were testing between low voltage...but I wasn't thinking that hard about it so I carefully stripped back the sheathing on both, flipped the switch on, then touched them together. What I was looking for was an arc, when the electricity jumps from one wire to the other. Well, it didn't so much arc as it did explode in my face.
There was a loud CRACK! And a blinding flash. I tripped one of the main breakers. Fortunately, I did not get hit with anything but a "welder's flash". I've heard about people getting hit with 277, and it if doesn't kill you, it'll at least knock you out, and I was up on a ladder.
Made me worry a little about my lack of insurance.