OSHA 10-Hour Construction ReviewFocus Four HazardsHard
A worker is operating a crane on a construction site. The crane is positioned near energized overhead power lines rated at 300 kilovolts (kV). According to OSHA standards, what is the minimum safe working clearance that must be maintained between the crane and these power lines?
- A25 feet
- B15 feet
- C20 feet
- D10 feet
Show answer & explanationAnswer & explanation
Correct answer: A. 25 feet
For overhead power lines rated between 251 kV and 350 kV, OSHA requires a minimum safe working clearance of 25 feet. This clearance distance increases with higher voltage to prevent electrocution from arcing.
Why the other options are wrong
- B. 15 feet is the minimum clearance for lines between 50 kV and 200 kV.
- C. 20 feet is the minimum clearance for lines between 201 kV and 350 kV, but 25 feet is specifically required for 251-350 kV.
- D. 10 feet is the minimum clearance for lines up to 50 kV, which is much lower than 300 kV.
Overhead Power Line Clearance (251-350 kV)
OSHA's required minimum safe distance between machinery (like cranes) and energized overhead power lines to prevent electrocution.
- Clearance depends on the voltage of the power line.
- For 251 kV to 350 kV, the minimum clearance is 25 feet.
- This distance accounts for potential arcing and unexpected movements.
Memory trick: Higher the 'V', further must 'Flee'!