MASS Electrical Safety and Power Line Awareness 1 — Questions and Answers
Question 1: According to OSHA 29 CFR 1926.1408, what is the minimum clearance distance required between a crane and overhead power lines rated up to 350kV during operations?
- 10 feet
- 15 feet
- 20 feet (Correct answer)
- 25 feet
Correct answer: 20 feet
OSHA 29 CFR 1926.1408 requires a minimum 20-foot clearance from power lines rated up to 350kV during crane and derrick operations.
Question 2: If a crane becomes energized after contacting a power line and the operator CANNOT move the equipment free, what is the correct action?
- Jump out of the cab immediately
- Remain in the cab and warn all ground personnel to stay away (Correct answer)
- Use the crane's fire extinguisher on the contact point
- Climb slowly down the crane to reach the ground
Correct answer: Remain in the cab and warn all ground personnel to stay away
When equipment is energized and cannot be freed, the operator must stay in the cab and warn others to stay clear until the utility company de-energizes the line.
Question 3: Before beginning crane operations near overhead power lines, who is responsible for determining the voltage of those lines?
- The crane operator on duty
- The on-site safety officer
- The employer or lift director (Correct answer)
- The local electrical inspector
Correct answer: The employer or lift director
OSHA places the legal responsibility on the employer to identify overhead power line hazards, including determining voltage, before operations begin.
Question 4: What is the primary purpose of an electrical proximity warning device (EPD) mounted on a crane?
- To measure the crane's boom angle and load moment
- To alert the operator when approaching the minimum clearance distance from energized power lines (Correct answer)
- To automatically shut down the crane engine when near power lines
- To log electrical faults in the crane's wiring system
Correct answer: To alert the operator when approaching the minimum clearance distance from energized power lines
Electrical proximity warning devices provide audible and/or visual alerts to crane operators as they approach the minimum safe clearance distance from energized conductors.
Question 5: What document or confirmation must be obtained from the utility company before a crane may operate inside the minimum approach distance to power lines?
- A line ownership certificate
- Written confirmation that lines have been de-energized, grounded, or insulated (Correct answer)
- A high-voltage work permit issued by the local authority
- An electrical inspection report from a licensed electrician
Correct answer: Written confirmation that lines have been de-energized, grounded, or insulated
OSHA requires written confirmation from the utility that lines are de-energized and grounded, or physically insulated, before any crane work is permitted inside the minimum clearance.
Question 6: If a ground worker observes a crane boom contact an overhead power line, what is the FIRST action they should take?
- Grab the crane to stabilize it against the line
- Attempt to pull the operator out of the cab
- Warn all personnel in the area to stay away from the crane (Correct answer)
- Dial 911 from a mobile phone while standing near the crane
Correct answer: Warn all personnel in the area to stay away from the crane
The immediate priority is preventing additional electrocutions; ground workers must clear the area because the ground around an energized crane can itself carry lethal step potential.
Question 7: Which of the following correctly describes the 'restricted approach boundary' in the context of electrical safety near power lines?
- The area where crane counterweights may swing freely
- The zone around energized conductors where unqualified workers must not enter without protection (Correct answer)
- The maximum boom radius allowed on a job site
- The perimeter marked by the lift director for rigging personnel
Correct answer: The zone around energized conductors where unqualified workers must not enter without protection
The restricted approach boundary defines the zone near energized conductors where unqualified workers face shock risk and must not enter without specific protective equipment and authorization.
MASS Electrical Safety and Power Line Awareness 1
According to OSHA 29 CFR 1926.1408, what is the minimum clearance distance required between a crane and overhead power lines rated up to 350kV during operations?