Abstract: At 3:50 p.m. on April 7, 2016, an employee was installing a return air plenum box in the attic of a residence. While manipulating the plenum box, measuring 12.5 inches by 24 inches by 24.5 inches, in an approximate 3 foot high crawl space of the attic, one of its sharp flanges sliced through an electrical cable that provided power to recessed lighting below. The energized cable carried 120 volts of electricity. As the lighting cable was contacted, the employee was electrocuted. The incident investigation revealed that no measures were in place to adequately protect the employee from electric shock hazards.