NCCCO Wire Rope Inspection and Replacement Criteria 2

Question 1

What is the discard criterion for wire rope based on broken wires in one lay length?

Accepted Answer

Six randomly distributed broken wires in one lay length, or three broken wires in one strand

Answer

ASME B30.2 and most standards specify that wire rope must be removed from service when six randomly distributed broken wires appear in one rope lay length, or when three broken wires are found in a single strand.

Question 2

What amount of diameter reduction from nominal size indicates a wire rope must be removed from service?

Accepted Answer

Reduction beyond specified ASME limits based on rope diameter (e.g., 3/64 inch for 9/16 to 3/4 inch rope)

Answer

Wire rope must be removed from service when diameter has been reduced beyond specified ASME limits for each rope diameter range, indicating loss of metallic cross-section.

Question 3

What is the primary purpose of wire rope lubrication during crane operations?

Accepted Answer

To reduce internal friction between wires and strands and protect against corrosion

Answer

Wire rope lubrication reduces internal friction between individual wires as the rope bends around sheaves and drums, dramatically reducing fatigue wire breaks, while also providing corrosion protection.

Question 4

Where on a crane wire rope are fatigue breaks most commonly found and why?

Accepted Answer

At areas of maximum bending, especially the first sheave from the drum

Answer

Fatigue wire breaks concentrate at sheave contact points, especially the first sheave from the drum, because this is where the rope experiences the greatest bending cycle frequency and bending stress concentration.

Question 5

What is fleet angle in wire rope operations and why must it be controlled?

Accepted Answer

Fleet angle is the angle between the rope path and the plane of the drum groove; excessive fleet angle causes uneven winding and rope damage

Answer

Fleet angle is the angle between the wire rope and the centerline of the drum groove; excessive fleet angle causes the rope to wind over itself or pile up on one end, damaging the rope and drum groove.

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO (National Commission for the Certification of Crane Operators) Practice Test

NCCCO Wire Rope Inspection and Replacement Criteria 2