At least these tracers get you into the right panel. For commercial service work you normally cannot kill power to suit yourself.
If possible I bring an extension cord to the troubled receptacle and attach a plug tester. I drag it to the panel and flick a few breakers. That's a permissive environment... like doping out the circuits at the start of a TI demolition.
Cell phones and a helpful/needy customer usually locate light circuits PDQ.
Non-contact tracers are of such limited utility (Greenlee 2007 or 2011) that I rarely break mine out.
I do like the Greenlee 801K for de-energized circuits in a hot system.
