If a lighting ballast fails, do you change it out hot? That's a fairly common practice, but you can get electrocuted by 277V just as surely as from a higher voltage. If you're on a ladder, the fall might kill you even if you survive the shock. When you lockout and tagout the breaker supplying that ballast, you inconvenience people who work in that area. Nevertheless, unwiring the ballast while hot puts you at risk.

If you really must change ballasts while others are working in the area (instead of between shifts), you can shrink the time window if you first wire the ballasts with listed quick disconnects. In fact, you can find quick disconnects made specifically for luminaires. These special connectors prevent reverse wiring and are finger-safe. Consequently, you can unplug the ballast just as safely as if you were unplugging a floor fan. You could convert to the quick disconnect configuration case by case as ballasts need replacement. However, consider scheduling a mass conversion during a normal plant (or office) shutdown, in a manner similar to mass re-lamping.

Caution: This quick disconnects don't eliminate ladder safety requirements. Rope off the area around the ladder. You don't want to drop a heavy tool onto someone's unprotected head. Nor do you don't want someone knocking your ladder over while you're on it.