Abstract: On October 18, 2006, a crew from Pouk & Steinle, Inc., a licensed utility construction contractor that was subcontracting for Southern California Edison Company, was dispatched for emergency repair. Upon arrival at the job site, the crew entered an underground vault to replace three "UG" transformers. After successful change out of the transformers, the crew foreman determined the need to remove the elbows on the J-bar, so that the crew could insulate the cable and find out why the cable was failing. The crew foreman directed Employee #1 to extract the elbows from the J-bar, using a hot stick, and the elbows were found to be in good condition. Employee #1 then used the hot stick, in an attempt to reinstall the elbows back to the J-bar. On his first attempt, the elbow blew up (i.e., an arc flash occurred), causing burns to Employee #1's head, hands, and neck. Employee #1 was determined to be the only crew member injured as a result of the explosion. Employee #1 was initially taken to Verdugo Hills Hospital, but paramedics later transferred him to Sherman Oaks Burn Center, where he was admitted for days (not specified). The Division determined that the accident was caused by Employee #1 attempting to reinstall an energized, nonload-break elbow to the J-bar. The crew mistook the nonload-break elbow for a load-break elbow, which could be disconnected or operated while energized, assuming all other safety precautions were taken. A serious citation was issued to the employer for failing to ensure that only permitted work be performed while employees were in the underground vault and handling energized cables or equipment in excess of 7,500 volts. The employer was also cited for failing to ensure that work such as removal of energized elbows be performed from outside the vault, so that affected employees could be protected from potential arc flash hazards.