Rigid optical fiber cables should be coiled carefully to maintain minimum bend radius, prevent kinks, and ensure tidy, maintainable layouts.

Key Principles

1. Respect Minimum Bend Radius: Always ensure the cable is not bent beyond its specified minimum radius, which is typically 15 times the cable diameter for working bends during installation and larger for storage . Exceeding this can damage the fiber and degrade signal quality.
2. Avoid Excessive Tension: Do not pull or stretch the cable beyond the manufacturer's recommended tensile load. Use the cable's strength members (e.g., aramid yarn) for pulling rather than the jacket unless specifically approved .
3. Figure-Eight Coiling for Long Cables: For long lengths, use a figure-eight pattern with loops 1.5–2.4 meters in diameter to prevent twisting and kinking. Place guides or cones to maintain loop spacing and relieve pressure at crossovers .
4. Splice Tray Coiling: After splicing, coil fibers individually in splice trays. Start from the middle and then coil both sides, or from one end depending on tray space. Secure heat-shrink sleeves and avoid overlapping fibers to prevent damage .
5. Special Situations: If fibers are unusually long or short, coil them separately at the ends. For cables with special devices or branch directions, handle each section individually to maintain proper layout and avoid sharp bends .
6. Securing Coils: For storage or mid-span coiling, secure the coil to a solid structure such as a manhole wall or messenger wire. Ensure the cable print orientation is consistent (inside or outside of the U-shape) to avoid twisting .
7. Tidiness and Maintenance: Proper coiling ensures fibers are easy to manage, reduces additional loss, and facilitates future maintenance. Avoid “bird's-nest” coiling by carefully measuring reserved lengths and coiling fibers neatly .

Practical Tips

• Pre-process cables and pigtails before coiling to calculate reserved lengths accurately.
• Use cardboard shims or a second figure-eight coil to relieve pressure at crossover points.
• For rigid outdoor cables, clamp at intervals to prevent sagging and maintain long-term load limits .
• Avoid automated coiling machines for rigid or armored cables, as they may exceed torsion and bend limits . By following these methods, rigid optical fiber cables can be coiled safely, maintaining signal integrity and ensuring a neat, maintainable installation.