Laying of Figure-8 Optical Cables

Figure-8 optical cable installation prevents twisting and kinking, ensuring safe and efficient deployment for aerial and ground applications.

What is Figure-8 Cable?

Figure-8 optical cable, also called self-supporting figure-8 cable, combines optical fibers with an integrated messenger wire in a distinctive “8” cross-section. This design allows the cable to be suspended between poles without additional support hardware, making it ideal for aerial deployments, rural broadband, urban pole-to-home drops, 5G backhaul, and utility co-deployment projects ( ). The cable consists of two main components:

• Messenger component: a steel strand providing structural support
• Cable component: the optical fiber core within a protective jacket This integration simplifies installation, reduces labor, and enhances durability ( ).

Figure-8 Installation on the Ground

When pulling cable from a reel or conduit, the figure-8 loop technique prevents twisting:

1. Lay the cable on the ground in a large figure-8 pattern, typically 6–12 feet (2–4 meters) per loop depending on cable stiffness ( ).
2. Use a tarp or plastic sheet to keep the cable clean.
3. Pull slowly, carefully forming the figure-8 to avoid kinks.
4. For a standard pull, pick up the cable and flip it so the end to be pulled is on top.
5. Attach the cable to the pull rope with swivel pulling eyes and continue the pull ( ). For midspan pulls on long runs:

• Place the reel at the midpoint of the span.
• Pull one end through the conduit to one side, then figure-8 the remaining cable on the ground.
• Pull the second end to the opposite side, eliminating the need to flip the cable on the ground ( ).

Aerial Installation

For aerial deployments:

• The figure-8 cable is suspended between dead-end poles using the messenger component.
• Ensure proper tensioning of the messenger strand to maintain structural integrity.
• Follow safety precautions, including wearing safety glasses and gloves, and avoid sharp bends or contact with power lines ( ).
• Slack loops should be installed according to manufacturer guidelines to accommodate thermal expansion and maintenance ( ).

Best Practices and Precautions

• Avoid kinking or twisting by maintaining smooth figure-8 loops.
• Keep the cable clean and free from debris during installation.
• Inspect the route for obstacles or uneven terrain that could damage the cable ( ).
• Follow local building codes and safety regulations, especially when working near power lines or in public areas ( ).
• Use appropriate tools and hardware; equivalent alternatives to brand-specific tools are acceptable ( ).

Advantages of Figure-8 Cable

• Self-supporting: no need for additional support hardware
• Durable: integrated messenger reduces mechanical stress
• Efficient installation: faster aerial deployment and reduced labor costs
• Versatile: suitable for long spans and various environmental conditions ( ) Figure-8 optical cable remains a preferred choice for modern fiber deployments due to its combination of mechanical reliability, ease of installation, and cost-effectiveness.