The openings in the sides and back of a panel box, called knockouts, are also required to be sealed if not used. Directly below the left missing twistout is a plastic blank that has been installed to cover opening where a circuit breaker has been removed.īecause a missing twistout allows the possibility of electric shock, it is a safety defect that a home inspector will call out in an inspection report. The two arrows in the photo above point to missing twistouts that have exposed the “live” interior components of the panel. If too many twistouts are removed or a breaker is later removed from the panel, there are plastic blanks, available at any hardware store, that can be snapped into the opening created in the deadfront.

While you may be used to seeing it in your home with circuit breakers arranged in two rows protruding through an opening in the plate, the panel is manufactured as a solid plate that is perforated with rectangular shapes called “twistouts” that can be literally twisted and snapped out individually by an electrician, who removes only as many twistouts as there are circuit breakers to be installed in the panel, so that when the installation is complete there are no openings in the front of the panel that allow any of the live wire connections-or the metal bus bars that run down the back of panel box and connect the breakers to the electric service-to be touched when the panel door is opened.

The metal plate screwed to the front of an electric panel is called a deadfront.

Twist out