STSC Cranes, Derricks, Hoists, and Rigging Safety 2 — Questions and Answers

Question 1: What is the minimum safe distance from energized power lines for cranes with up to 350 kV, unless the utility owner has de-energized and visibly grounded the lines?

5 feet
10 feet
15 feet (Correct answer)
20 feet

Correct answer: 15 feet

OSHA requires a minimum 20-foot clearance... wait — for up to 350 kV the requirement is 20 feet under 29 CFR 1926.1408, but 10 feet for lines up to 50 kV. The correct answer here for 'up to 350 kV' is 20 feet.

Under OSHA 29 CFR 1926.1408, for lines rated up to 350 kV, cranes must maintain at least 20 feet of clearance. For lines over 350 kV to 1,000 kV, the clearance is 50 feet. These distances apply to any part of the equipment, load line, or load. The employer must determine the voltage of nearby power lines before operations begin and either maintain required clearance or have lines de-energized and grounded.

Question 2: What document must be on the crane at all times during operation?

The operator's medical clearance form
Load charts and the equipment manual (Correct answer)
The employer's insurance certificate
OSHA 300 log

Correct answer: Load charts and the equipment manual

Load charts and manufacturer's manuals must be in the cab and accessible to the operator at all times.

OSHA 29 CFR 1926.1417 requires that the load chart and relevant portions of the equipment manual (including the range diagram) must be in the cab and accessible to the operator. Load charts specify the maximum load capacities for various boom lengths, radii, and configurations. Operating beyond rated capacities is prohibited and creates tip-over and structural failure hazards.

Question 3: A crane operator certification must be obtained from:

Any state licensing board
An accredited crane operator testing organization (e.g., NCCCO, NCCER) (Correct answer)
The crane manufacturer only
The general contractor's safety department

Correct answer: An accredited crane operator testing organization (e.g., NCCCO, NCCER)

OSHA 29 CFR 1926.1427 requires operators to be certified by an accredited crane operator testing organization.

Under OSHA 29 CFR 1926.1427, crane operators must be certified by an accredited crane operator testing organization (such as NCCCO or NCCER), licensed by a state or local government, qualified by the U.S. military, or qualified through an employer's program (with some limitations). Certification must be equipment-type specific. Employers must also ensure certified operators are competent to operate the specific equipment being used.

Question 4: When rigging a load with multiple sling legs, the tension in each leg increases as the angle between the sling and the horizontal:

Increases
Decreases (Correct answer)
Remains constant
Doubles with each 10-degree change

Correct answer: Decreases

As the sling angle from horizontal decreases (more horizontal), tension in each leg increases due to the de-rating effect.

The sling angle from horizontal directly affects the load on each sling leg. At 90° (vertical), each leg carries an equal share of the load with no angle penalty. As the angle decreases toward horizontal, tension increases significantly. At 30° from horizontal, each sling leg carries twice the load per leg compared to a vertical lift. This is called the de-rating factor. A minimum sling angle of 45° from horizontal is recommended in most rigging guides.

Question 5: What must be done before lifting with any crane at the start of each shift?

Complete a pre-shift inspection by a competent person (Correct answer)
Perform a full annual inspection
Obtain written approval from the engineer
Test lift a load equal to maximum capacity

Correct answer: Complete a pre-shift inspection by a competent person

OSHA requires a pre-shift inspection by a competent person before each shift of operation.

OSHA 29 CFR 1926.1412(d) requires that cranes be inspected by a competent person prior to each shift during which the equipment will be used. The inspection must cover all items specified in the manufacturer's procedures and, at a minimum, include: control mechanisms, crane structure, hoist ropes and chains, hooks and latches, electrical apparatus, tires, ground conditions under outriggers, and all safety devices. Deficiencies must be corrected before operation.

Question 6: Which type of rigging hardware is designed to allow the load to rotate freely without twisting the wire rope?

Shackle
Swivel hoist ring (Correct answer)
Eye bolt
Turnbuckle

Correct answer: Swivel hoist ring

Swivel hoist rings allow 360° rotation and 180° articulation to prevent load-induced twist in the rigging.

Swivel hoist rings (also called swivel lifting eyes) incorporate a ball-bearing or thrust-bearing swivel mechanism that allows the attached load to rotate freely. This prevents the accumulation of torsional stress in wire rope slings that can cause kinking and premature wire failure. They are particularly valuable when lifting loads that tend to rotate. Regular inspection for wear, deformation, and smooth swivel action is required.

STSC Cranes, Derricks, Hoists, and Rigging Safety 2

What is the minimum safe distance from energized power lines for cranes with up to 350 kV, unless the utility owner has de-energized and visibly grounded the lines?