Abstract: An apprentice electrician was drilling holes through studs to run Romex cable in the loft of a building under construction. He backed up from stud to stud to do the drilling. While he was backing up, the employee reached an open unguarded floor hole that was 667 millimeters long and 514 millimeters wide. He fell about 3 meters to the third floor and sustained a fractured right kneecap. Emergency medical services placed him on a board and raised him to the loft, from which he was hoisted to a helicopter and transported to a hospital. Surgery was performed to pin the kneecap. He was hospitalized for his injuries.