A 38-year-old laborer was electrocuted when the jackhammer he was using struck an underground power line. The incident happened at a hospital parking lot where his employer was a subcontractor hired to install a storm water drainage system. His employer was a site preparation contractor.

His job duties for this project included digging trenches and laying and connecting storm drain pipe. On the day of the incident, the victim and two other employees were digging trenches and installing storm drains. At the location they were working there was a buried duct bank which was in the way and conflicted with the plans for installing the storm drain.

This duct bank contained three lines of PVC electrical conduit piping encased in concrete. Each line of conduit piping contained four power line cables carrying 7,200 volts each. In order to install the storm drain pipes to the necessary grade, the employees were using an excavator, breaker bar, and a rivet-buster-type jackhammer to chip away at the duct bank concrete.

The victim was in the trench chipping the duct bank’s concrete when his rivet buster punctured the conduit and contacted the power line cable. He was electrocuted and died at the scene.

Incident scene where the laborer struck the 7,200-volt power line with his jackhammer as he was chipping away at the concrete encasement of the duct bank.

Final Word

Inspectors had the following recommendations to prevent future similar incidents: Determine the exact locations of buried power lines before beginning work.

• Always assume that power lines are energized unless you have confirmation from the power line owner or utility company that the lines have been de-energized and grounded.

• Do not perform work that may expose employees to contact with energized power lines.

• General contractors and subcontractors should plan before the start of a project and coordinate during the project on a site safety plan that identifies and addresses hazards to employees.

http://www.lni.wa.gov/Safety/Research/Face/Files/711362015LaborerElectrocuted.pdf