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Wire Rope & Rigging Components

2 hours

Learning Objectives

  • •Explain the construction of wire rope and why different constructions are used for running vs. standing ropes
  • •Apply OSHA 1926.1413 removal-from-service criteria to determine if a wire rope must be replaced
  • •Correctly reeve a wire rope through a sheave block and identify fleet angle requirements
  • •Select appropriate rigging hardware and hitch configurations for common crane lifts

Topics Covered

  • •Wire rope construction: core (fiber core vs. independent wire rope core IWRC), strands, and individual wires
  • •Running rope: the moving hoist and boom hoist line — typically 6×19 or 6×37 construction for flexibility
  • •Standing (pendant) rope: used in static applications; typically 6×7 construction — stiffer, more abrasion-resistant
  • •Rotation-resistant rope: used on single-part hoist lines; special construction prevents load rotation
  • •OSHA 1926.1413 removal criteria — running rope: 6 randomly distributed broken wires in one lay, or 3 in one strand in one lay
  • •OSHA 1926.1413 removal criteria — rotation-resistant rope: 2 broken wires in 6 rope diameters, or 4 in 30 diameters
  • •OSHA 1926.1413 removal criteria — diameter reduction: remove if rope has worn more than 5% from nominal diameter
  • •Mandatory removal regardless of wire count: kinking, birdcaging, core protrusion, prior power line contact, heat damage, broken strand
  • •Reeving: the arrangement of wire rope through a system of sheaves to create mechanical advantage (multiple parts of line)
  • •Parts of line: the number of rope segments between the hook block and the boom top — more parts = more capacity but slower speed
  • •Fleet angle: the angle between the rope and the plane of the sheave groove — smooth drum maximum 1.5°; grooved drum maximum 2°
  • •Minimum drum wraps: at least 2 full wraps must remain on the drum at maximum hook lowering (OSHA 1926.1417)
  • •Sheave inspection: check groove diameter, groove wear, flange cracks; use sheave gauge to verify proper groove profile
  • •Rigging hardware: shackles, hooks, rings — all must be rated with Working Load Limits (WLL); never use unmarked hardware
  • •Wire rope slings: single-leg, 2-leg bridle, 3-leg bridle; WLL varies by hitch type and sling angle — sling angle below 30° drastically reduces effective WLL

Resources

OSHA 1926.1413 — Wire rope — inspection

osha

Required

OSHA 1926.1414 — Wire rope — selection and installation criteria

osha

Required

Self-Check Questions

Question 1: During your wire rope inspection you find 5 randomly distributed broken wires in one lay of a running rope. What must you do?

  1. A. Continue operation — OSHA allows up to 6 broken wires per lay in running rope(correct)
  2. B. Remove the crane from service — 5 broken wires in one lay meets the removal threshold
  3. C. Reduce maximum load by 25% and complete the shift
  4. D. Reeve an additional part of line to reduce tension per wire
Show Explanation

Explanation:

OSHA 1926.1413 requires removal when running rope has 6 or more randomly distributed broken wires in one rope lay, or 3 or more broken wires in one strand in one rope lay. Five broken wires spread across the lay does not yet meet the 6-wire threshold — however, the inspector must confirm the wires are randomly distributed and not concentrated in one strand. Any concentration of 3 in one strand IS a removal condition. Track the count and recheck daily.

Question 2: A wire rope shows a "birdcage" deformation — the strands have expanded outward forming a cage shape. What is the correct action?

  1. A. Apply wire rope lubricant and use at reduced capacity
  2. B. Straighten the rope with a wooden block and proceed
  3. C. Remove the rope from service immediately — birdcaging is a mandatory removal condition(correct)
  4. D. Use the rope for pendant applications only since it is a standing rope condition
Show Explanation

Explanation:

Birdcaging means the inner rope core has expanded relative to the outer strands, permanently damaging the rope structure. It is a mandatory removal condition under OSHA 1926.1413 regardless of visible broken wires. The rope's load distribution is destroyed and it cannot be safely used in any application.

Question 3: What is the maximum fleet angle for wire rope on a smooth winch drum?

  1. A. 0.5°
  2. B. 1.5°(correct)
  3. C. 2.0°
  4. D. 3.0°
Show Explanation

Explanation:

The maximum allowable fleet angle for a smooth (un-grooved) drum is 1.5°. Excessive fleet angle causes the rope to scrub against the sheave flange as it wraps, stripping lubrication and accelerating outer wire wear. Grooved drums allow up to 2° fleet angle.

Question 4: A wire rope that previously made contact with an energized power line must be:

  1. A. Inspected by a competent person and returned to service if no wires are broken
  2. B. Downgraded to pendant use only since pendants are not load-bearing running ropes
  3. C. Replaced — prior power line contact is a mandatory removal condition(correct)
  4. D. Used at 50% of rated working load with heightened monitoring
Show Explanation

Explanation:

OSHA 1926.1413 lists prior contact with an energized power line as a mandatory removal condition. Electrical current can cause internal heat damage and annealing (softening) of wire steel that is invisible on the surface but destroys tensile strength. The rope cannot be returned to service regardless of how it looks.

Question 5: Increasing the number of parts of line in the reeving system on a crane hoist does which of the following?

  1. A. Increases the speed at which the hook travels
  2. B. Increases the maximum rated load capacity but decreases hook speed(correct)
  3. C. Decreases both the load capacity and the speed
  4. D. Has no effect on capacity — load capacity is determined by the drum only
Show Explanation

Explanation:

Adding more parts of line (rope segments between the hook block and the boom top) multiplies the lifting force by distributing the load across more rope segments. This increases rated capacity. However, the hook travels slower per drum revolution because more rope must be wound per inch of hook travel.

Question 6: During a rigging inspection, you find a shackle with no Working Load Limit (WLL) marking. What should you do?

  1. A. Estimate the WLL based on the shackle pin diameter
  2. B. Use the shackle for lifts under 1 ton since unmarked hardware is usually light duty
  3. C. Remove the shackle from service — rigging hardware without a WLL marking must not be used(correct)
  4. D. Check with the crew to see if anyone knows the rating
Show Explanation

Explanation:

All rigging hardware must have a documented Working Load Limit. Unmarked hardware has no verified rating and cannot be used in a lift. Using hardware of unknown capacity is a serious violation — rigging failures are a leading cause of crane fatalities.

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