BIEDINGER FATALITY: PG&E INVESTIGATION COMPLETE
PGE has completed their investigation into the fatal accident involving Gerald “Jerry” Biedinger, a T&D Equipment Operator from Angels Camp who was working in Tuolumne:
Gerald “Jerry” Biedinger, a 57 year old T&D Equipment Operator with 33 years of Company experience, was fatally injured on August 20, 2010, at approximately noon while working in a rural area near the city of Tuolumne. He was electrocuted due to touch potential when he became the path to ground from an energized highway digger.
Biedinger was assigned to dig four pole holes for a new construction project near the city of Tuolumne. Work was scheduled to extend existing electrical overhead lines by three spans to accommodate the request.
An electric crew was at the jobsite on Monday, August 16, 2010, to frame and place four new poles near the marked locations. At that time, because the USA marking request had not been completed, the crew was not able to dig the holes and was scheduled to return the following Saturday to complete the project. In order to expedite setting the poles on Saturday, the crew requested the holes be dug by Friday.
On Wednesday, August 18, Jerry visited his family physician for a personal medical condition and was prescribed medication which was labeled as potentially causing impairment.
On Friday morning, August 20, Jerry arrived to work at his headquarters in Angels Camp and was directed to contact the Sonora Headquarters temporary supervisor regarding a work assignment near the city of Tuolumne. Jerry arrived at the Sonora Headquarters at approximately 8:30 a.m., and after a brief discussion of the job with the temporary supervisor, Jerry was offered an observer to accompany him, but he declined the offer. Jerry followed the temporary supervisor to the work location.
At the jobsite, the temporary supervisor drove Jerry to three of the four locations, pointed out where the holes were to be dug, and mentioned the overhead lines above the inter-set pole location (Hole #4). Jerry drove the highway digger to the location (Hole #1) furthest from the 17 kV lines and began to work.
Jerry completed digging three pole holes by approximately 11:30 a.m. before moving to the next location (Hole #4). As Jerry was raising the boom to dig the fourth pole hole, the boom came in contact with one conductor of the overhead single phase 17 kV line, resulting in the vehicle becoming energized at approximately 9800 volts (17 kV to ground voltage). Contact marks were found on the boom guide rollers and conductor indicating that, as the boom was raised, it contacted the conductor for 31 inches before coming to rest.
For some unknown reason, Jerry exited the rear of the vehicle. It has been determined that his leather work gloves and work boots insulated him from touch potential as he exited the energized truck. Analysis of the leather gloves and work boots determined that the gloves provided approximately 2,000 volts of insulation and the boots provided some level of insulation up to approximately 8,000 volts.
Based on evidence collected, it was determined that Jerry made contact with the auger at his upper left thigh. At this point, the insulation value of Jerry’s boots was exceeded, allowing the current to pass through his legs.
After initial contact with the energized auger, one primary fuse failed and de-energized the single phase in contact with the boom. The second primary fuse remained intact and continued to energize the vehicle through back feed (approximately 2,600 volts).
After the initial contact with the auger, Jerry fell to the ground where he laid in contact with the outrigger stabilizing leg, where fatal injuries occurred.