What is the required vertical clearance for overhead conductors over public streets?

The required vertical clearance for overhead conductors over public streets is 18 feet. This regulation is designed to ensure safety for vehicles, pedestrians, and any tall structures that may pass underneath the power lines. The 18-foot clearance helps to reduce the risk of accidental contact with the lines, particularly from large vehicles such as trucks or construction equipment, which may not always be able to accurately judge their height and the height of overhead lines. The specified clearance also allows for some degree of natural sag that may occur in the wires due to temperature fluctuations or weight from ice or snow, thus providing a margin of safety.