Assume all overhead lines are energized and potentially dangerous.
Keep all personnel and equipment as far away as possible from overhead power lines, including the service drops that run from utility poles to buildings.
Personnel, ladders and fully extended aerial equipment must never get closer than 20 feet from lines up to 50,000 volts; higher voltages on large transmission towers require clearances of up to 50 feet.
Use a spotter to monitor placement of aerial equipment.
Always maintain the maximum possible safety clearance.