OK, sitting in traffic and wandering thru my mind, this memory jump up.
Way back, doing the demo portion of a jewelry showroom & work areas, I was on the last section of wall with only two receptacles in it. ALL circuits in both panels are cut out. I stitch the Wiggy in, and the receptiacles are ‘hot’. Scratch head?? Check panels, confirm only temp lights and temp GFIs & nothing else. Check common area panel, & confirm all off. Anger sets in, I want to go home. Remove 1 receptacle, do a hot to ground short; sparks flying, copper gone, still ‘hot’. Now the sparks set the old carpet pad on fire. Did the proverbial Mexican hat dance, & ran for water.
Found the circuit about an hour later, source was a little old two circuit FPE sub panel, in the slop sink room marked ‘do not turn off’. Add additional anger!!
Does this count as a dumb move??