Abstract: An employee was operating a metal-encased 0.5-inch electric drill with a 2.5-inch hole saw attachment. He was cutting a hole in the outside wall of a residence as part of the installation of a heat pump. He was drilling through an area between the floor joist and the base plate. The drill bit cut into a 120-volt non-metallic sheathed cable that was part of the premises wiring. The employee, who was perspiring and who was kneeling on the ground, received an electric shock as a result of the ground fault and could not let go of the drill. He was transported to a local hospital by emergency medical services. He was revived several times during transport, but was pronounced dead by ventricular fibrillation on arrival at the hospital.