NCCER Crane Load Charts & Rigging Principles 2 — Questions and Answers
Question 1: When using a load chart at a 60-degree boom angle versus a 45-degree boom angle, what generally happens to the rated capacity?
- Capacity increases at 60 degrees (Correct answer)
- Capacity decreases at 60 degrees
- Capacity remains the same regardless of boom angle
- Capacity only changes when the load radius changes
Correct answer: Capacity increases at 60 degrees
As boom angle increases, the load radius decreases, which generally increases the rated lifting capacity per the load chart.
Question 2: What is the purpose of the 'working area restriction' section found in many crane load charts?
- To indicate where the operator must stand
- To define zones where reduced or no lifts are permitted due to structural limitations (Correct answer)
- To show where the outriggers must be placed
- To list the maximum number of parts of line allowed
Correct answer: To define zones where reduced or no lifts are permitted due to structural limitations
Working area restrictions identify sectors (such as over the rear or over the side) where the crane's rated capacity may be reduced or lifting is prohibited.
Question 3: A synthetic web sling has a vertical hitch capacity of 10,000 lbs. In a basket hitch configuration around a smooth cylindrical object, what is the approximate capacity?
- 5,000 lbs
- 10,000 lbs
- 20,000 lbs (Correct answer)
- 15,000 lbs
Correct answer: 20,000 lbs
A basket hitch around a smooth, symmetric load doubles the rated vertical capacity, giving approximately 20,000 lbs.
Question 4: On a mobile crane load chart, 'on outriggers fully extended' versus 'on rubber' ratings differ because:
- Tire pressure affects load chart values
- Outriggers provide a wider, more stable base that allows greater rated capacities (Correct answer)
- Rubber ratings are always higher due to cushioning
- Load chart ratings are identical for both configurations
Correct answer: Outriggers provide a wider, more stable base that allows greater rated capacities
Outriggers transfer crane loads to a larger footprint on the ground, increasing stability and allowing higher rated lifting capacities.
Question 5: What does 'derating' a crane mean in practical terms?
- Increasing the boom length to lift heavier loads
- Reducing the rated capacity below chart values to account for job-site conditions (Correct answer)
- Raising the load slowly to avoid dynamic loading
- Replacing wire rope with a higher-rated rope
Correct answer: Reducing the rated capacity below chart values to account for job-site conditions
Derating means intentionally reducing the crane's working load limit below the load chart value to account for factors like wind, ground conditions, or load dynamics.
Question 6: When a crane load chart lists a capacity in 'boom point' configuration, the operator must also account for the weight of:
- The fuel in the crane
- The hook block, headache ball, and any rigging hardware hanging from the boom (Correct answer)
- The outrigger pads
- The cab and counterweight separately
Correct answer: The hook block, headache ball, and any rigging hardware hanging from the boom
Hook blocks, headache balls, and rigging gear are considered 'below-the-hook' equipment and their weight must be deducted from the chart's rated capacity to determine net load capacity.
Question 7: A load chart shows 28,000 lbs capacity at a 30-ft radius. The hook block weighs 800 lbs and the rigging weighs 400 lbs. What is the maximum net load that can be lifted?
- 28,000 lbs
- 27,200 lbs
- 26,800 lbs (Correct answer)
- 28,400 lbs
Correct answer: 26,800 lbs
Net load capacity = 28,000 − 800 (hook block) − 400 (rigging) = 26,800 lbs.
NCCER Crane Load Charts & Rigging Principles 2
When using a load chart at a 60-degree boom angle versus a 45-degree boom angle, what generally happens to the rated capacity?