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. To prevent electrocution, what is the minimum safe clearance distance that must be maintained between any part of the crane or its load and power lines rated at 35 kV?
- A25 feet
- B10 feet
- C20 feet
- D15 feet
Show answer & explanationAnswer & explanation
Correct answer: B. 10 feet
According to OSHA 1926.1408, for energized overhead power lines rated 50 kV (kilovolts) or less, the minimum safe clearance distance that any part of the crane or its load must maintain is 10 feet. Since 35 kV falls into this category, 10 feet is the required minimum clearance.
Why the other options are wrong
- A. 25 feet is the clearance required for power lines over 350 kV up to 500 kV.
- C. 20 feet is the clearance required for power lines over 200 kV up to 350 kV.
- D. 15 feet is the clearance required for power lines over 50 kV up to 200 kV, not 35 kV.
Crane Overhead Power Line Clearance (< 50 kV)
The minimum safe distance that a crane or its load must maintain from energized overhead power lines to prevent electrocution, based on the line's voltage.
- For lines 50 kV or less, the minimum clearance is 10 feet.
- Contact with power lines is a leading cause of crane-related fatalities.
- A spotter is often required when working near power lines.
Memory trick: Under 50kV, ten feet you'll see!