From Mason Country Meter Mafia.

Tuesday, I experienced a 3-phase, 480 volt arc flash. I was exchanging a meter for a pump house. It had a safety socket. I used the top studs for my jumpers because they wouldn’t fit on the bottom.

Everything was going fine. I got the new meter in, and was removing the jumpers. I loosened all three, and as I started to remove the last one, it flashed. I had a pre-planned escape route, and used it. The only damage to me was a sooty face shield and a faintly toasted keeper. My tool bag, however, was a total loss. Still have no idea why it happened.