Abstract: A tree trimmer was performing line-clearance tree-trimming work near a 12.47-kilovolt (phase-to-phase) overhead power line. He was working from an aerial lift. A ground worker was working about 45 meters away. The aerial lift truck was parked facing downhill alongside a road. The power line crossed the road approximately 6 meters from the downhill side of the truck. The tree trimmer had finished trimming branches on the side of the road with no power line. With the boom elevated above the power line, the tree trimmer swung the aerial lift bucket to trim branches away from the power line on the other side of the road. After he began trimming on that side of the road, he moved the bucket to another position. He lost sight of the power line, and the boom contacted the power line. The tree trimmer heard an arcing noise and felt the additional tension on the boom from the power line. He immediately moved the bucket to a higher location, away from the power line. No one was injured in the accident.