Abstract: At 3:45 p.m. on August 27, 2019, an employee, a maintenance worker, was installing a latch lock at the base of an electrical panel so that it is accessible to only certain authorized personnel, not to the public. While installing the latch lock at the base of the electrical panel, the employee lifted the dead front cover to drill the third hole for the latch, because the dead front cover has a protruding stopper. While drilling the third hole for the third screw with a cordless hammer driver drill (Manufacturer: Makita, Model: XPH07), that third screw got stuck. Then, the employee put the drill in reverse, and when he hit the trigger, the drill swung back into the energized buss bar of the electrical panel, creating an electric arc and burning his right hand. The employee suffered from first and second degree burns on his right hand and was treated without hospitalization. Cal/OSHA identified several causal factors, including but not limited to: the supervisor was notified about the work task and did not ensure that it is safe to do so, employee was not qualified to work in proximity to live electrical systems, employee assumed that it is safe to install a latch lock and lift the dead front cover of the electrical panel. Employee suffered from first and second degree burns on his right hand. The employee exposed himself to the energy from electric arc derived from the live electrical components of the panel.