Inspection Detail

Inspection: 1270640.015 - Delta Utility Services, Inc.

Inspection Information - Office: Department Of Labor, Licensing, And Regulation Division Of Labor And Industry Maryland Occupational Safety And Health

Investigation Summary

At 12:15 p.m. on October 13, 2017, Employee #1, a crew leader, and his crew were removing the old transformer and replacing it with a new one. The power was supplied to the transformer by an underground cable, originating at the overhead A-phase power line. The phase-to-phase voltage was 13.2kV and the phase-to-ground voltage was 7620v. The underground cable was rated to handle as great as 600 amperes. The crew needed to isolate and de-energize the transformer prior to removing it. There were two underground cables coming off of the A-phase overhead power line and neither one was labeled or identified, so the employees needed to test the amperage of the cables to determine which cable was associated with the transformer to be replaced and which cable fed power to an unrelated loop. Employee #1 used an insulated bucket truck to raise himself approximately 35 feet, to access the underground cable at the pole where it met the overhead power line. The employee was using an Amprobe ACDC-100 TMRS amperage/voltage tester, rated for up to 800 amperes, to attempt to determine the correct cable. He received an irregular or faulty reading that was inconclusive and thought that the meter was malfunctioning. The employee lowered himself to the ground and obtained the wire leads for the testing equipment, which are intended to be used for voltage testing at a maximum rated voltage of 600 volts. He ascended back to the work area. Employee #1 touched the positive probe lead of his tool to the primary conductor and touched the negative lead to the concentric neutral of the same cable, causing a phase-to-ground contact and resulting in an arc flash. The blown fuse created a very loud popping sound. The employee, now covered in soot, lowered himself to the ground and began to remove his personal protective equipment which included a hard hat, safety glasses, rubber sleeves, rubber gloves, and leather gloves, as well as FR clothing. He was transported to a nearby hospital and treated for second degree burns to his forehead, cheeks, chin, and left ear. The employee was release from the hospital the following day.

Keywords: Bucket Elevator, Burn, Ear, Electric Arc, Electrical, Elevated Work Platform, Face, Fuse, Heat, PPE, Power Lines, Transformer, Voltage Backfeed