Uncategorized Mobile Crane Operator 1 — Questions and Answers
Question 1: According to OSHA 1926.1416, what is the minimum frequency at which wire rope on running rigging must be inspected?
- Once per month
- Before each shift or at the start of each day of use (Correct answer)
- Once per week
- After every 40 hours of use
Correct answer: Before each shift or at the start of each day of use
OSHA 1926.1416(d)(1) requires that wire rope used in hoisting operations be visually inspected before each shift or at the beginning of each day the equipment is used, checking for kinks, broken wires, corrosion, and other defects.
Question 2: A signal person uses the following signal: arm extended horizontally, forearm vertical, hand open, and fingers pointing up — then moves the hand in small horizontal circles. What does this signal mean?
- Hoist slowly
- Dog everything (stop)
- Use main hoist (Correct answer)
- Travel (move the crane)
Correct answer: Use main hoist
The 'use main hoist' standard hand signal is given with one arm extended horizontally, forearm vertical, hand open with fingers pointing up, and the hand moving in small horizontal circles. This distinguishes which hoist the operator should engage.
Question 3: When determining whether ground conditions are adequate for crane operations, which factor is MOST critical to evaluate before setting outriggers?
- The color-coded soil classification on the site survey
- The bearing capacity of the ground relative to outrigger load (Correct answer)
- The distance from the outriggers to the nearest utility line
- The manufacturer's recommended outrigger pad color
Correct answer: The bearing capacity of the ground relative to outrigger load
Ground bearing capacity is the most critical factor when setting outriggers. If the soil cannot support the concentrated load transmitted through the outrigger pads, the crane can tip or sink, causing a catastrophic collapse. Load charts assume adequate ground support.
Question 4: Under OSHA 1926.1407, before any part of a crane can operate closer than 20 feet to a power line rated above 350 kV, what must the employer do?
- Install a proximity alarm on the boom tip
- De-energize and ground the power line, or confirm a minimum clearance with the utility owner (Correct answer)
- Post a warning sign visible from the cab
- Assign two signal persons — one on each side of the crane
Correct answer: De-energize and ground the power line, or confirm a minimum clearance with the utility owner
OSHA 1926.1407 requires that before operating within the Table A minimum clearances for high-voltage lines (20 ft for lines up to 350 kV, more for higher voltages), the employer must either have the utility de-energize and visibly ground the line, or determine the voltage and confirm required clearance distances with the utility owner.
Question 5: What is the purpose of an anti-two-block (ATB) device on a mobile crane?
- It prevents the crane from swinging past 360 degrees of rotation
- It automatically stops hoist motion before the hook block contacts the boom tip or sheave (Correct answer)
- It limits the load line from exceeding the rated capacity shown on the load chart
- It locks the outriggers in the fully extended position during lifts
Correct answer: It automatically stops hoist motion before the hook block contacts the boom tip or sheave
An anti-two-block device detects when the hook block is approaching the boom tip or upper sheave and automatically cuts power to the hoist, preventing two-blocking. Two-blocking can cause the load line to part or structural damage to the boom, potentially dropping the load.
Question 6: When operating a mobile crane, wind speed must be monitored because high winds can affect the rated capacity. According to general industry guidance, at what sustained wind speed should a crane operator typically consult the manufacturer's load chart for wind derating or cease operations?
- 15 mph
- 20 mph (Correct answer)
- 30 mph
- 40 mph
Correct answer: 20 mph
Most crane manufacturers and industry standards, including guidance from ASME B30.5, recommend operators consult the manufacturer's guidelines and consider suspending operations when sustained winds reach or exceed 20 mph (approximately 30 ft/sec), as wind significantly increases the effective load and can cause the boom or load to swing unpredictably.
Uncategorized Mobile Crane Operator 1
According to OSHA 1926.1416, what is the minimum frequency at which wire rope on running rigging must be inspected?