Fiber Optic Cable Sheath Content

Fiber optic cable sheaths are designed to protect the internal fibers from mechanical, environmental, and chemical stresses, with materials and construction varying by application and installation type.

Sheath Materials and Types

Polyethylene (PE): Common for outdoor and aerial cables, offering UV stability, weather resistance, and chemical resistance to diesel and mineral oils (IEC60811-404). Low Smoke Zero Halogen (LSZH): Used for indoor applications to reduce toxic fumes in case of fire.

Anti-

Tracking (AT) Jackets: Applied in high-voltage environments to prevent electrical tracking along the sheath.

Construction Variants

Single Sheath: A single protective layer, often sufficient for short spans or low-stress environments. Double Sheath: Provides additional mechanical strength and protection for longer spans or high-stress aerial installations. Armored Cables: Incorporate steel tape or wire braiding between the sheath layers for rodent protection and mechanical reinforcement.

Environmental and Mechanical SpecificationsUV and Weather Resistance: Outdoor sheaths are UV-stabilized and weather-resistant to withstand prolonged sun exposure and varying climates. Water Blocking: Loose tube designs often include gel or water-blocking tapes to prevent moisture ingress. Temperature Range: Typical operational ranges vary from -20°C to +70°C for indoor cables and -5°C to +50°C for outdoor micro-cables.

Mechanical Strength: Sheaths may include aramid yarn or steel wires as peripheral strength members to support tensile loads during installation and operation.

Additional Features

Color Coding and Marking: Outer sheaths are often marked with fiber type and cable type for easy identification. Rodent Protection: Some outdoor cables include additional layers or armored sheaths to prevent damage from animals. Chemical Resistance: Certain sheaths are resistant to oils, fuels, and other chemicals encountered in industrial environments.

Summary

Fiber optic cable sheaths are selected based on installation environment, mechanical stress, chemical exposure, and fire safety requirements. Outdoor cables typically use PE or armored sheaths with UV and water resistance, while indoor cables often use LSZH sheaths for fire safety. Double-sheath and armored designs provide additional protection for aerial or high-stress applications, ensuring long-term reliability and fiber integrity.