Central Loose Tube (CLT) optical cables should be installed using careful pulling, proper bend radius, figure-eight coiling, and mid-span access techniques to prevent fiber damage and ensure optimal performance.

Cable Handling and Preparation

Before installation, ensure the cable is stored on a flat, firm surface and protected from sharp objects, flooding, or extreme temperatures. Protective material on reels should remain in place until installation, and LSZH or PE jackets must be handled carefully to avoid cracks or mechanical stress ( ). Record cable identification markings, including sheath number, footage, and description codes, for future reference ( ).

Pulling and Laying Techniques

1. Pulling Tension: Apply pulling force only to the cable's strength members, not the outer jacket, to prevent elongation and fiber damage. Use a pulling grip of at least 600 mm to distribute tension evenly ( ). Maximum pulling tension for stranded loose tube cables is typically around 600 lbF (2,700 N), but always check the cable specification sheet ( ).
2. Bend Radius: Maintain the minimum bend radius during installation. For example, multiply the cable diameter by 15 to determine the working bend radius, and double this for pull wheels or rollers ( ).
3. Figure-Eight Coiling: When unreeled on the surface, lay the cable in a figure-eight pattern to prevent twisting and kinking. Loop sizes typically range from 2–4 m for general cables or 1.5–2.4 m for duct installations ( ). Slightly offset each loop to minimize mechanical pressure.
4. Slack Loops: Leave slack loops at known mid-span access points to facilitate routing and storage within closures. A typical slack loop length is around 96 inches (244 cm) ( ).

Mid-Span and End Access

1. Sheath Removal: Mark the cable for sheath removal (usually 2 meters from the end for termination). Use a sheath knife to make ring cuts 4–6 inches apart, flex the cable to separate the sheath, and remove it carefully to expose the ripcord and core ( ).
2. Buffer Tube Access: Use a buffer tube access tool or slitter to prevent fiber damage. Identify the buffer tube reversal point to safely unwind the tubes. For high fiber count cables, remove outer layers first, then handle inner layers similarly ( ).
3. Ripcord Handling: Pull ripcords carefully to split the jacket and armor without damaging fibers. Tie knots in ripcords and use pliers to guide the pull ( ).

Installation Precautions

• Avoid sharp turns, edges, and excessive bending.
• Pull slowly and steadily to prevent kinks.
• Use protective sheets when the cable end is on the ground.
• Ensure all personal protective equipment is worn, including gloves and safety glasses, especially when handling fibers that may carry laser light ( ). By following these methods, Central Loose Tube optical cables can be installed safely, maintaining fiber integrity and ensuring long-term network performance.