Wire Rope: Construction, Selection, and Inspection

Wire Rope in Traction Elevators

Traction elevators rely entirely on wire ropes (also called hoisting ropes) to suspend and move the car and counterweight. Unlike hydraulic systems, there is no cylinder to catch a failing component — the ropes are the primary load-carrying members. Keeping them in safe working condition is one of the most critical inspection tasks an elevator mechanic performs, and ASME A17.1 Safety Code for Elevators and Escalators sets the minimum requirements for rope condition and removal from service.

How Wire Rope Is Built

A wire rope is not a single strand of metal. It is assembled in layers:

1. Individual wires — the smallest element, drawn from high-carbon steel.

2. Strands — a group of wires twisted together around a center wire.

3. Core — the central member that the strands are laid around.

4. The rope itself — multiple strands laid helically around the core.

Core types matter for elevator ropes:

• Fiber Core (FC) — a natural or synthetic fiber rope at the center. It is flexible and acts as a lubricant reservoir, but offers less support under heavy side loading.
• Independent Wire Rope Core (IWRC) — a small wire rope used as the core. It is stronger, more crush-resistant, and better suited to high-load traction applications.

Most modern traction elevator ropes use IWRC for its dimensional stability under load.

Lay describes the direction and pattern wires and strands are twisted:

• Regular lay — wires are twisted opposite to the direction the strands are laid; the most common type for elevator ropes because it resists rotation and wear against the sheave groove.
• Lang's lay — wires and strands twist in the same direction; more flexible but less commonly specified for elevators.

Common Defects and What Causes Them

| Defect | Description | Typical Cause |

|---|---|---|

| Broken wires | Individual wires fractured across their cross-section | Fatigue from repeated bending over sheaves |

| Corrosion | Rust, pitting, or dark discoloration between strands | Moisture, salt air, or insufficient lubrication |

| Kinking | Permanent sharp bend that distorts the rope geometry | Improper uncoiling, overloading, or rope reversal |

| Worn (abraded) sections | Flattened outer wires, reduced diameter | Contact wear against sheave grooves or guide elements |

| Valley breaks | Wire fractures inside the strand, hidden from surface view | Advanced fatigue; more dangerous than surface breaks |

Inspection Procedure

Personal Protective Equipment

Before touching any rope:

• Wear leather-palm gloves — broken wire ends are razor-sharp.
• Apply lockout/tagout (LOTO) procedures on the elevator machine before any hands-on inspection of rope terminations or rope sections near the machine room. Follow your site-specific energy control program.
• Safety glasses are required whenever working around wire rope.

Step-by-Step Field Inspection

1. Visual scan the full accessible rope length. Use a magnifying loupe to count broken wires in any section equal to one rope lay length and in any section equal to thirty rope lay lengths (consult ASME A17.1 for the specific numerical limits in the applicable rule).

2. Check rope diameter. Using a 6-inch vernier caliper, measure the rope at three separate locations, measuring across the full rope (not strand to strand). Record all three readings. A reduction in rope diameter beyond the code limit indicates core failure or severe internal wear.

3. Inspect terminations. Examine sockets, shackles, and hitch plates for cracks, corrosion, and secure attachment. Rope ends must be properly socketed or have approved end attachments; no improvised connections are acceptable.

4. Check for kinks and distortion. A kinked rope must be removed from service immediately — no straightening attempt is permitted.

5. Feel for corrosion. Run gloved fingers along the rope; gritty or flaky texture between strands indicates active corrosion.

6. Record all findings on the standardized inspection log: date, rope identification, diameter readings at each point, defect type and location, and your accept/reject determination.

Accept or Reject — The Code Standard

ASME A17.1 specifies removal-from-service criteria for elevator wire ropes. The code addresses: the number of broken wires in a given lay length, the presence of any kink or distortion, diameter reduction beyond specified limits, and evidence of heat damage or corrosion that has caused pitting. When any single criterion is met, the rope must be replaced before the elevator returns to service. Your inspection log must reference the specific requirement in plain language so a supervisor or inspector can verify your judgment without having to locate the code section themselves.

Why Accurate Record-Keeping Matters

An incomplete inspection form is a safety failure, not a paperwork failure. Blank measurement fields mean no baseline exists for the next inspection. Missed defects can allow a rope to remain in service past its safe limit. Both the NEIEP/IUEC apprenticeship program and NAEC CET certification expect candidates to demonstrate that they can apply code requirements to real conditions and document findings clearly. Employers rely on these records for maintenance scheduling, liability protection, and regulatory compliance.