Abstract: A mason and his helper were working on a section of block wall that was 5.3 meters tall. They were working from a scaffold that had been erected beneath a 7200-volt-to-ground, three-phase overhead power line. The outrigger scaffold was 4.3 meters from the power line, and the top ring of the scaffold was 3.0 meters from the power line. (The employees were using a 910-millimeter ring at the top of the scaffold for guardrails as they realized they were getting close to the power line.) The weather had gotten colder, and the employees put a canopy (a hoop and flexible plastic covering) over the scaffold and wall. The canopy was 910 millimeters above the top of the scaffold.) The mason and his helper pushed a 4.3-meter length of rebar through the covering and lifted it to the top of the wall core area for insertion into the wet grout in the core of the block. When the helper released the rebar, it contacted the power line, electrocuting the mason.