The minimum vertical clearance for overhead feeder conductors not exceeding 1,000V passing over commercial areas subject to truck traffic is _____ ft.

• A. 12
• B. 18
• C. 24
• D. 30

Answer: (B)

The key idea is to maintain safe vertical clearance for overhead conductors over areas where vehicles operate. For overhead feeder conductors not exceeding 1,000 V that pass over commercial areas with truck traffic, the NEC requires a minimum vertical clearance of 18 feet. This height provides a protective margin for conductor sag, temperature effects, and the typical heights of trucks and loading equipment, reducing the chance of contact. Measured from the ground to the lowest point of the conductor, this 18-foot requirement helps keep live parts safely out of reach during normal conditions and worst-case sag. Other clearances would be unnecessary here because 18 feet is the code-prescribed height for this scenario, ensuring adequate protection for vehicular traffic while avoiding excessive clearance.