Abstract: At approximately 10:38 a.m. on October 18, 2011, Employee #1 and Employee #2, of San Francisco Bay Area Rapid Transit District, both Train Control Electronic Technicians, were repairing an inoperative button control for Switch 81 located on track RR3. The control was a Presence Detector, an electrical device that uses a conductive loop inside of 0.75 in. PVC pipe that runs along the surface of the ballast to form a loop and detect if a train has entered the area. As the work was performed on Switch 81, for some reason Switch 83 became damaged. Employee #1 was replacing the newly damaged switch, using a metallic crimping tool, and an arc flash occurred on Employee #1's hand or the metallic crimping tool made contact with the third rail. Employee #1 received an electrical shock and was transported to Doctors Hospital in San Pablo, where he was treated and released. This incident was deemed not reportable.