NCCCO Hazard Identification and Power Line Safety 4 — Questions and Answers
Question 1: When a crane is operating near energized power lines and the boom inadvertently contacts the line, what should the operator do FIRST?
- Immediately exit the cab and run away
- Stay in the cab and sound the horn to warn others (Correct answer)
- Attempt to pull the boom away from the line by retracting
- Shut down the engine and wait for rescue
Correct answer: Stay in the cab and sound the horn to warn others
The operator should remain in the cab (the safest place) and sound the horn to warn ground personnel to stay clear, then contact the utility company.
Question 2: Under OSHA 1926.1408, what is the minimum approach distance for a crane operating near power lines rated between 50 kV and 200 kV?
- 10 feet
- 15 feet (Correct answer)
- 20 feet
- 25 feet
Correct answer: 15 feet
For lines rated 50 kV to 200 kV, OSHA requires a minimum approach distance of 15 feet.
Question 3: A 'spotter' assigned to monitor power line clearance during crane operations should be positioned where?
- In the crane cab with the operator
- At a location with a clear view of the power line and the crane's boom (Correct answer)
- Directly below the load path
- At the signal person's designated position only
Correct answer: At a location with a clear view of the power line and the crane's boom
The spotter must be positioned where they can clearly see both the power line and the crane components to accurately judge clearance distances.
Question 4: What does the term 'step potential' refer to in the context of crane-power line contact incidents?
- The voltage drop across a transformer step-down
- The difference in ground voltage between two points a step apart near an energized object (Correct answer)
- The incremental voltage applied to a crane's controls
- The rated voltage step-up from the utility's substation
Correct answer: The difference in ground voltage between two points a step apart near an energized object
Step potential is the voltage difference between two ground points a step apart, which can electrocute a person walking near an energized object touching the ground.
Question 5: When planning a lift near power lines and the utility company cannot de-energize the lines, what is the next required action per OSHA?
- Cancel the lift entirely
- Proceed using a qualified signal person
- Establish and use a minimum approach distance based on voltage (Correct answer)
- Install rubber insulating sleeves on all cable sections
Correct answer: Establish and use a minimum approach distance based on voltage
If de-energizing is infeasible, OSHA requires determining the line voltage and establishing an appropriate minimum approach distance for the crane to maintain.
Question 6: Which of the following conditions creates an increased electrocution risk for crane operators even when maintaining the standard 10-foot clearance from power lines?
- Operating in windy conditions that could cause boom sway (Correct answer)
- Using a lattice boom instead of a telescoping boom
- Performing a tandem lift with two cranes
- Lifting during daylight hours in summer
Correct answer: Operating in windy conditions that could cause boom sway
Wind can cause the boom or load line to sway unpredictably, reducing the actual clearance below the required minimum even when the initial position was compliant.
Question 7: A crane operator notices an unmarked overhead wire crossing the jobsite. What is the correct first action?
- Assume it is a communication line and proceed with caution
- Treat it as energized and contact the utility company to confirm its status (Correct answer)
- Lower the boom below the wire height and continue
- Ask the signal person to walk under the wire to inspect it
Correct answer: Treat it as energized and contact the utility company to confirm its status
All unidentified overhead lines must be treated as energized until the utility company confirms otherwise — assumptions can be fatal.
NCCCO Hazard Identification and Power Line Safety 4
When a crane is operating near energized power lines and the boom inadvertently contacts the line, what should the operator do FIRST?