I did commercial lighting for a few years. Relamp/reballast or LED retrofits are almost always done during business hours, with the lights on. Big lighting syst

I did commercial lighting for a few years. Relamp/reballast or LED retrofits are almost always done during business hours, with the lights on. Big lighting systems usually run at 277V. (Phase-to-neural voltage of 480V three-phase) I would much rather work on a hot 277V lighting fixture than a 120V wall socket. Much more room to work, wire gauge is way thinner. The downside is that you're always on a ladder, so a big shock is comes with a ten foot fall as a free bonus. If I'm touching anything inside a wall, the breaker is getting flipped.