I should know better; I was installing a new fan and rather than kill the power at the breaker, I made sure the fan controller was off then used my non-contact probe to confirm there was no power at the box. Voltage probe indicated no juice but there’s apparently some leakage in the fan controller and while mounting the new fan mount bracket on the ceiling box I knocked of the wire nut I had twisted on the hot wire. No zap but a small arc and the fan controller STB.
Dumb move, why didn’t you use the are gap switch, and dubious safety practices comments aside, does anyone know if these things are fused internally? They’re put together with odd triangular broach screws so pulling it apart is going to require a little custom tool work.