NCCCO Mobile Crane Operator Test 1 3 — Questions and Answers
Question 1: When operating a mobile crane near an unguarded energized power line of unknown voltage, the minimum safe approach distance is:
- 3 feet
- 6 feet
- 10 feet
- 20 feet (Correct answer)
Correct answer: 20 feet
OSHA 1926.1408 requires a minimum 20-foot clearance from energized lines when voltage is unknown.
Question 2: A load chart rating for a mobile crane is based on which structural condition of the crane?
- Crane in good working order with rated capacity deducted for wear
- New crane with no prior lifts
- Crane on level, firm ground with all outriggers fully extended (Correct answer)
- Crane on any ground surface with outriggers partially deployed
Correct answer: Crane on level, firm ground with all outriggers fully extended
Load charts assume the crane is on firm, level ground with all outriggers fully extended and set on pads.
Question 3: Which of the following conditions requires an operator to immediately cease crane operations?
- Wind speed reaches 15 mph
- The load line becomes slightly slack during a pick (Correct answer)
- The crane's rated capacity indicator shows operation within 90% of rated load
- Visibility drops below 1 mile
Correct answer: The load line becomes slightly slack during a pick
A slack load line can cause sudden uncontrolled load movement or two-blocking, requiring immediate stoppage.
Question 4: What is the purpose of a load moment indicator (LMI) on a mobile crane?
- To measure wind speed and direction during a lift
- To alert the operator when the crane approaches its rated capacity (Correct answer)
- To calculate the exact center of gravity of the load
- To monitor hydraulic pressure in the outrigger system
Correct answer: To alert the operator when the crane approaches its rated capacity
An LMI (also called a rated capacity indicator) warns the operator as the crane nears its load limit for the current configuration.
Question 5: During a lift, the operator notices the load is slowly swinging uncontrollably. The FIRST action should be to:
- Increase hoist speed to tension the line and stop the swing
- Lower the load to the ground as smoothly as possible (Correct answer)
- Raise the boom to shift the center of gravity
- Signal the rigger to grab the load and stop it manually
Correct answer: Lower the load to the ground as smoothly as possible
An uncontrolled swinging load should be landed as safely and smoothly as possible to eliminate the hazard.
Question 6: On a mobile crane, the 'working area' or 'working range' is defined as:
- The total area the crane can reach at maximum boom extension
- The arc through which the crane can swing while carrying a load within rated capacity (Correct answer)
- The region within 10 feet of the crane's counterweight
- The full 360-degree swing radius at ground level
Correct answer: The arc through which the crane can swing while carrying a load within rated capacity
The working area is the specific arc and radius within which the crane can safely operate a rated load in its current configuration.
Question 7: Which factor does NOT reduce a mobile crane's rated lift capacity?
- Operating on a side slope
- Using a jib attachment
- Reducing the operating radius (Correct answer)
- Swinging over the crane's rear
Correct answer: Reducing the operating radius
Reducing the operating radius (working closer to the crane) generally increases available capacity, not decreases it.
NCCCO Mobile Crane Operator Test 1 3
When operating a mobile crane near an unguarded energized power line of unknown voltage, the minimum safe approach distance is: