What Is the Difference Between Trailing Cable and Reeling Cable?
A reeling cableis a specialized category of flexible cable designed specifically for use with cable reels (drums). These cables provide a continuous power supply to mobile equipment—such as gantry cranes, stackers, and ship-to-shore (STS) systems—by automatically winding and unwinding as the equipment moves. While the term is sometimes used interchangeably with trailing cable, the two serve different mechanical functions and are engineered to withstand distinct types of physical stress. Using a cable in an application for which it was not designed often leads to premature failure, such as internal conductor fatigue or external sheath rupture.
This article provides a brief overview of each cable type before focusing on a detailed technical comparison to help professionals identify the correct solution for reducing equipment downtime and optimizing lifecycle costs.
What is a Trailing Cable? Definition and Typical Uses
A trailing cable is a flexible power cable designed to follow or "trail" behind mobile machinery. These cables are primarily used in environments where equipment moves along a horizontal path, and the cable is allowed to lie on the ground or is supported by a series of loops (festoons) or protective drag chains. They are standard in open-cast mining, underground tunneling, and large-scale construction sites.
Design Focus: External Protection
The first design emphasis in a trailing cable is on its ability to resist any external damage. As a result, trailing cables often require a rugged outer covering due to their exposure to harsh elements during use. Such outer coverings are usually made of thermosetting rubber or special plastics that are highly resistant to impact and chemicals.
What is a Reeling Cable? Operational Principles and Mechanical Strength
The reeling cable is particularly designed for use where there is a need for a cable reel or drum operation. While the trailing cable requires no physical force while moving because it is simply pulled along, a reeling cable will experience a lot of mechanical action during each cycle of movement of the machinery.
Design Focus: Tensile and Torsional Resistance
The main technical issues involved in the design of reeling cables are those of tensile stress (the force applied axially by the reel motor) and torsion (the twisting force when the cable is wound at high speeds). In order to counteract these effects, reeling cables incorporate a core strength member together with a torsion-resistant braid, usually of aramid fiber, positioned between the inner and outer jackets.
Trailing Cable vs. Reeling Cable: The Technical Comparison
The differentiating factor about these cables is the nature of their internal structure and mechanical behavior within the operating conditions. The discussion in the subsequent sections elaborates on the technical comparison between the two types.
1. Mechanical Stress Profiles: Tension vs. Abrasion
The first and foremost point of contrast arises from the kind of stress that the cable is made to resist.
Trailing Cable: The main type of stress that the cable will face includes abrasion and compression. The trailing cable should be sturdy enough to withstand being dragged on the ground and possibly being crushed by light vehicles. They have low tensile resistance since they are not used to being pulled by a motor-driven drum.
Reeling Cable: The primary stresses are tension, torsion, and cyclic bending. While it also requires a durable sheath, its internal design is focused on preventing the conductors from shifting or twisting under the constant pull of the reel.
2. Internal Construction and Layering
To survive the reeling process, the internal geometry of a reeling cable is more complex than that of a standard trailing cable.
- Conductor Stranding: Reeling cables use ultra-fine copper stranding to increase flexibility and fatigue resistance. Trailing cables also use flexible stranding, but the requirements for cyclic bending are typically less stringent.
- Anti-Torsion Reinforcement: High-quality reeling cables feature a "double-sheath" design with an embedded aramid or polyester braid. This braid locks the inner and outer components together, preventing the "corkscrew" effect (where the cable develops a permanent spiral twist). Trailing cables usually lack this specific anti-torsion layer.
- Center Strength Member: Many reeling cables include a core made of vulcanized rubber or aramid cord to absorb pulling forces, a feature rarely found in trailing cables.
3. Operational Mechanics and Speed
The speed and direction of movement dictate which cable is appropriate.
Reeling Cables are designed for high-speed operation, often exceeding 120 meters per minute in horizontal applications and 60 meters per minute in vertical spreader applications. They are optimized for "active" management.
Trailing Cables are best suited for "passive" management at lower speeds. When used in drag chains or festoons, the speed is limited by the mechanical integrity of the supporting structure rather than the cable itself.
4. Typical Failure Modes
Understanding how these cables fail is essential for selection:
Trailing Cable Failure: Usually starts with a sheath breach, leading to moisture ingress and short circuits, or "cold flow" where the insulation deforms under constant pressure.
Reeling Cable Failure: Often manifests as internal "conductor breakage" or "corkscrewing." If a cable not designed for reeling is used on a drum, the conductors will eventually "bunch up" in one section of the cable because they cannot handle the torsional stress of winding.
Summary Table of Technical Differences
Feature | Trailing Cable | Reeling Cable |
Primary Movement | Dragging / Hanging (Passive) | Winding / Unwinding (Active) |
Force Resistance | Abrasion, Impact, Compression | Tensile Strength, Torsion, Cyclic Bending |
Internal Support | Standard fillers | Aramid braids / Central strength members |
Typical Environment | Mining, Tunneling, Construction | Ports, Steel Mills, Material Handling |
Bending Requirement | Flexing in one plane (usually) | Constant multi-axial bending |
Selection Recommendations and Best Practices
When deciding between a reeling cable and a trailing cable, engineers should evaluate the application based on the "Force-Path-Frequency" model:
- Force: If the application requires a motorized reel to pull the cable, a reeling cable is mandatory. A trailing cable will stretch and fail under the constant tension of a reel motor.
- Path: If the cable path involves vertical lifting (such as a spreader on a container crane), the cable must be a reeling type with high tensile support. Horizontal paths on flat ground can often utilize trailing cables if no reel is involved.
- Frequency: For high-cycle applications (where the equipment moves back and forth hundreds of times per day), the superior fatigue resistance of a reeling cable justifies the higher initial investment by preventing unplanned maintenance.
Conclusion
The difference between the use of reeled cables and trailing cables is based on their behavior under mechanical loads. Although trailing cables prove efficient in providing passive power transmission in harsh conditions, reeled cables are highly advanced structures that are able to resist the tension and torque loads applied during the process of active winding. The correct choice of cable configuration is vital for guaranteeing the reliable operation of mobile industrial equipment.
Spreader vertical reel cablesrepresent our solution for highly sophisticated vertical heavy tension applications. Moreover, if you need highly efficient medium voltage transmission for large port equipment, you can opt for our MV reel cable. Feel free to contact us if you have any questions!
END
-------------------------------------------------------------------------------------------------------------------------------------------------------------------
about HEBEI- HUATONG
Founded in 1993, Hebei-Huatong is a global cable manufacturing enterprise with production facilities located in Tangshan (Hebei Province, China), Busan (South Korea), Panama, Kazakhstan, Tanzania, Cameroon, and Angola. Its core product portfolio includes submersible pump cables for oil extraction, flexible moving cables for harbor cranes, cUL/CSA listed cables for AI PDU and marine shipboard cables. The company provides robust support for the continuous, safe, and efficient operation of industrial sectors worldwide, including offshore and onshore oil & gas exploration, and material handling via port cranes.
WhatsApp