What is the vertical clearance requirement for overhead conductors over commercial parking areas?

The correct vertical clearance requirement for overhead conductors over commercial parking areas is 18 feet. This standard is established to ensure safety for vehicles and pedestrians, allowing for large trucks and emergency vehicles to pass underneath without risk of contact with electrical conductors.

An 18-foot clearance helps prevent electrical hazards that could arise from vehicles that might exceed typical height limits, such as delivery trucks or recreational vehicles. Additionally, maintaining this clearance minimizes the chances of accidental contact, which could lead to electrical shock or power outages.

The other options represent lower clearances that do not adequately provide the necessary safety margin over commercial areas, where higher vehicle traffic and larger vehicle sizes are common.