Abstract: At approximately 7:25 a.m. on December 8, 2013, Employee #1, an underground cable man, was performing his assigned task responding to a power outage. The employee opened the lid to an underground secondary transformer enclosure and checked the secondary leads with an amperage meter. There was a zero reading on the amperage meter. He visually inspected the transformer tank, primary elbows, secondary bushings, and secondary leads to look for signs of any trouble. The next step was to reset the breaker. Employee #1 attempted to reset and close the breaker with an 8 ft stick when an internal arc created an internal explosion of ignited oil vapors. The employee stumbled backwards and suffered second degree burns to his hands and face. The employee called his employer to inform him about the incident and requested for medical assistance. Employee #1 was transported to San Francisco General Hospital, where he was treated for his facial and hand burns.