Aerial fiber optic cables are typically suspended using messenger strands or self-supporting designs, with careful tensioning, lashing, and hardware fittings to ensure safe, low-stress installation.

Overview of Suspension Methods

Fiber optic cables in aerial applications are generally supported in two ways:

1. Lashed to a Messenger Strand: A steel wire, known as a messenger or suspension strand, is installed between poles or support structures. The fiber optic cable is then lashed to this strand using a small-gauge wire, maintaining proper tension and sag to withstand the cable's weight and environmental loads such as wind, ice, or snow .
2. Self-Supporting Cables: Some cables, like All-Dielectric Self-Supporting (ADSS) or Figure-Eight cables, carry their own messenger. ADSS cables use aramid yarn for strength, eliminating the need for a separate strand, while Figure-Eight cables have a built-in messenger portion to support the optical fibers .

Installation Techniques

Moving Reel Method

• Used when the route is accessible by vehicles.
• The cable is unspooled from a moving reel and simultaneously lashed to the messenger strand.
• Lashing begins at the far end of the run and progresses toward the reel location .

Stationary Reel / Pull-In Method

• Applied when the route is inaccessible to vehicles.
• The cable is pulled into place beneath the strand and temporarily supported by cable blocks.
• Lashing is performed after the cable is positioned .

Cable Lashing

• A small-gauge wire is helically wrapped around the cable and messenger strand.
• Lashing must maintain proper tension to prevent excessive sag while avoiding stress that could damage the fiber.
• Dead-ends and figure-eight configurations require careful attention to tension and sag limits .

Hardware and Fittings

• Suspension Clamps: Installed at intermediate poles to support the cable's weight while allowing natural catenary curves. Cushioned designs prevent micro-bending of fibers .
• Tension/Dead-End Clamps: Used at span endpoints, directional changes, or road crossings to transfer horizontal tension to the pole structure .
• Preformed Helical Rods: Distribute mechanical stress and prevent sheath abrasion at clamp points .
• Additional Accessories: UV-resistant wraps, cable markers, and dampers may be used to protect against environmental damage and vibration .

Key Considerations

• Cable Handling: Avoid sharp bends, excessive pulling tension, and crushing forces to prevent fiber damage .
• Sag Management: Ensure the messenger and cable sag are within safe limits for the span length and environmental conditions .
• Safety: Personnel must follow occupational safety regulations, wear protective equipment, and adhere to local codes . By following these methods and using appropriate hardware, aerial fiber optic cables can be installed efficiently while maintaining long-term performance and minimizing signal loss.