Overhead service conductors shall have a minimum clearance from final grade of 24½ feet when installed over which location?

• A. Recreational vehicle parks
• B. Tracks of railroads
• C. Public streets subject to truck traffic
• D. Rivers subject to boat traffic

Answer: (B)

The requirement tests understanding of how vertical clearance for overhead service conductors varies by location. Tracks of railroads demand the greatest height because trains and their equipment can be tall and move under the line, and wires can sag with temperature or be disturbed by passing equipment. To prevent contact and provide a safe margin for all these factors, the standard specifies a minimum clearance from the final grade of 24½ feet when overhead service conductors cross railroad tracks. Other locations—like streets with truck traffic, RV parks, or rivers—have different, typically lower clearances based on the kinds of hazards present there, so they don’t call for as much height as railroad tracks.