How to lay fiber optic cables in a figure-eight shape

Laying fiber optic cables in a figure-eight shape prevents twisting and kinking, ensuring safe handling and smooth installation. Purpose of the Figure-Eight TechniqueThe figure-eight method is used to store or deploy fiber optic cable without introducing twists. By looping the cable in a figure-8 pattern, a half twist on one side is counteracted on the other, which prevents tangling and preserves the integrity of the fibers during long pulls or midspan installations.

Ground-

Based Figure-

Eight InstallationPrepare the Cable and Surface: Pull the cable out of the conduit or reel and lay it on a clean surface, such as a tarp, to prevent dirt contamination. Form the Loops: Create large figure-8 loops on the ground. Typical loop sizes range from 6 to 12 feet (2–4 meters) depending on cable stiffness.

Lay Carefully: Pull the cable slowly while forming the figure-8 to avoid kinks or sharp bends. Flip for Pulling: If pulling from one end, use several installers to lift and flip the cable so the end to be pulled is on top. Attach it to the pull rope with swivel pulling eyes and continue the pull.

Midspan Pulls: For long spans, place the reel at a midpoint. Pull one end through the conduit, figure-8 the remaining cable on the ground, and then pull the second end to the opposite side.

Aerial Figure-

Eight Installation

Survey and Plan: Identify supporting structures (poles, towers) and determine the required cable length. Prepare Supports: Install brackets or clamps to anchor the cable securely. Inspect the Cable: Uncoil the figure-8 cable and check for damage, twists, or kinks.

Attach and Guide: Secure one end to the first support and guide the cable along the route, maintaining proper tension and avoiding excessive bending. Calculate Sag: Determine the appropriate sag based on span length, cable weight, wind, and temperature to prevent stress on the cable. Suspend the Cable: Use suspension hardware at regular intervals to maintain the figure-8 orientation and ensure stability.

Safety Considerations

Wear safety glasses and gloves to protect against fiber shards and sharp tools. Avoid sharp bends or kinks that can damage the fiber. Ensure proper handling during flipping or lifting to prevent strain on the cable.

Key Tips

Use self-supporting figure-8 cables for aerial installations to reduce the need for additional support hardware. Maintain consistent loop size to prevent uneven tension. For long runs, consider intermediate automated pullers to facilitate continuous pulls without damaging the cable.

By following these steps, fiber optic cables can be safely laid in a figure-eight shape, whether on the ground for storage and pulling or suspended aerially between supports, ensuring reliable performance and minimal risk of damage.