Mobile Crane Operator 4 Flashcards
7 cards from real NCCCO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Mobile Crane Operator 4 flashcards as text
When operating a mobile crane near energized power lines, what is the minimum required clearance distance for lines rated up to 50 kV under OSHA standards?
Answer: 10 feet
OSHA 1926.1408 requires a minimum 10-foot clearance from energized power lines rated up to 50 kV.
A crane's load chart shows a capacity of 40 tons at a 30-foot radius. If the operator works at a 40-foot radius, what generally happens to the rated capacity?
Answer: It decreases
As the load radius increases, the rated lifting capacity decreases due to increased moment (torque) on the crane structure.
What is the primary purpose of an anti-two-block (ATB) device on a mobile crane?
Answer: To prevent the hook block from contacting the boom tip
An ATB device automatically stops the hoist when the hook block approaches the boom tip sheaves, preventing two-blocking which can cause catastrophic failure.
Which document must an operator consult to determine the correct reeving configuration for a specific lift?
Answer: The crane manufacturer's load chart and operator manual
The crane manufacturer's load chart and operator manual specify correct reeving based on the load weight and configuration.
A mobile crane is set up on outriggers over a suspected underground utility. What should the operator do FIRST?
Answer: Call 811 to locate buried utilities before setup
Calling 811 (Dig Safe/Call Before You Dig) to locate utilities before setup is required to prevent striking buried lines during outrigger deployment.
What does it mean when a crane's load chart is derated for 'pick and carry' operations?
Answer: The rated capacity is reduced because traveling with a load increases dynamic forces
Pick and carry operations involve dynamic forces from travel that reduce safe capacity, so manufacturers derate the chart for these conditions.
Under ASME B30.5, what is the minimum number of wire rope wraps that must remain on the drum when the hook is at its lowest working position?
Answer: 2 wraps
ASME B30.5 requires at least 2 full wraps of wire rope to remain on the drum to maintain the rope's dead-end anchorage under load.