Steel wire inside the optical fiber cable

Steel wire in optical fiber cables provides mechanical protection, tensile strength, and rodent resistance, making the cables suitable for harsh environments and direct burial applications.

Purpose of Steel Wire in Fiber Optic Cables

Steel wire is incorporated into fiber optic cables primarily as armor to protect the delicate optical fibers inside. This steel wire armoring (SWA) serves several key functions:

• Mechanical Protection: The steel wires shield the fibers from crushing, impact, and bending stresses, which is critical in underground, industrial, or outdoor installations where physical damage is likely .
• Tensile Strength: Steel wire provides high tensile strength, allowing the cable to withstand pulling forces during installation and long-term tension in aerial or duct deployments .
• Rodent and Pest Resistance: The steel armor prevents damage from rodents and other animals that may chew through the cable .
• Environmental Durability: Armored cables resist moisture, soil acidity, UV exposure, and other environmental factors, ensuring stable optical transmission over long distances .

Types of Steel Wire Armored Fiber Cables

1. Standard SWA (Steel Wire Armored) Cables: These cables feature steel wire armor between the inner sheath and outer jacket, often with stranded loose tubes and water-blocking elements. They are suitable for direct burial, industrial networks, railways, and outdoor installations .
2. High Strength Steel Wire (HSSW) Armored Cables: These use galvanized plow steel armor for enhanced mechanical performance, offering near ten-fold improvement in tensile strength, two-fold crush resistance, and three-fold impact resistance compared to traditional steel tape armored cables. HSSW cables are ideal for extreme conditions such as pipelines, oil and gas fields, and heavy industrial sites .

Additional Considerations

• Loose Tube Construction: Many SWA cables use loose tube designs to protect fibers from mechanical stress and environmental factors while allowing flexibility .
• Water-Blocking Elements: Gel-filled tubes or water-blocking yarns prevent moisture ingress, which is essential for underground or outdoor installations .
• UV-Resistant Outer Jacket: Protects the cable from sunlight and weather exposure, extending its service life .

Applications

Steel wire armored fiber optic cables are widely used in:

• Telecommunication backbones and fiber internet infrastructure
• Industrial automation systems and heavy-duty industrial networks
• Direct burial installations in underground or harsh outdoor environments
• Railways, power grids, and oil & gas fields where mechanical stress and environmental hazards are significant In summary, steel wire in optical fiber cables is essential for mechanical protection, tensile strength, and environmental resilience, enabling reliable high-speed data transmission in challenging conditions.