What is the minimum safe distance from a power line to allow when installing an antenna?

Power lines carry lethal voltages, and safety regulations require you to plan for the worst-case scenario when installing a tower or antenna. If the structure were to completely collapse, it must be far enough away from any power lines to avoid making contact. The National Electrical Safety Code (NESC) and general safety practices require a 10-foot minimum safety clearance to prevent high-voltage arcing and electrocution. Therefore, the minimum safe distance is the total height of the antenna structure plus at least 10 extra feet. Distractors involving half-wavelengths or simple multipliers do not provide the absolute physical clearance required to guarantee your safety during a catastrophic fall.