Despite everyone’s best intentions, switch boxes and electric-outlet boxes sometimes project a bit beyond the plane of the drywall. Left this way, the cover plate won’t seat properly, leaving an unsightly gap around the plate. To eliminate this problem with plastic and fiberglass boxes, I grind down any protrusions with a wood rasp. This operation is best done right after the drywall is installed — before the electrician arrives.
Sebastian Eggert, Port Townsend, WA