One of the practical things I lernt from MSHA was "never stand directly in front of a circuit breaker when switching it". Had a 100 amper grenade on me once. Not fun.
Not even sure what the amps were on this. I think the 6-8 subpanels it feeds are at least 100's. I'll have to look tomorrow. When I ran the refrig systems I was frequently throwing 500A or bigger like they were light switches. LOL