Installing fiber optic cables in conduits requires careful planning, proper conduit selection, tension management, and lubrication to protect the delicate fibers and ensure long-term performance.

Planning and Preparation

Before installation, conduct a site survey to determine the route, obstacles, and end-points. Ensure the conduit path allows for future expansion by leaving 25–40% extra space for additional cables. Verify local permits and building codes, and select the appropriate fiber type (single-mode or multimode, armored or dielectric) based on bandwidth and environmental requirements .

Conduit Selection

Choose a conduit material suitable for the environment:

• HDPE (High-Density Polyethylene): Flexible, durable, ideal for underground or long continuous runs.
• PVC (Polyvinyl Chloride): Rigid, suitable for exposed areas or building transitions.
• Innerducts: Smaller tubes inside a larger conduit to separate fibers and reduce friction . Ensure the conduit diameter accommodates the cable and allows for smooth pulling, especially for multiple cables or future upgrades.

Cable Handling and Pulling

• Attach the cable to a pull string using a swivel pulling eye to prevent twisting.
• Pull only on the strength members (e.g., Aramid yarn), never on the outer jacket or glass fibers.
• Use a water-based, cable-compatible lubricant to reduce friction, particularly for long runs or multiple bends .
• Maintain a smooth, continuous pull without exceeding the manufacturer's maximum tension (commonly around 600 lb for outdoor cables) and respect the minimum bend radius (typically 20 times the cable diameter under tension), . For complex or long pathways, consider mid-span access points to re-lubricate and manage tension.

Coiling and Unreeling

• Use a figure-eight pattern when uncoiling cable to prevent kinks and twists.
• Keep loops within recommended diameters (e.g., 5–8 ft) and avoid coiling long continuous lengths .

Installation Safety and Protection

• Barricade areas where cable is unreeled to prevent pedestrian or vehicle interference.
• For buried conduits, maintain proper trench depth (commonly 18–36 inches) and place warning tape above the conduit for future excavations .
• When penetrating walls or floors, use approved fire-stop compounds.
• Monitor ambient temperature to stay within the cable's installation rating (typically −30 °C to +60 °C), .

Post-Installation

• After pulling, fibers must be terminated or spliced according to standards.
• Inspect the installation for bends, tension, and potential damage.
• Test the fiber for continuity and signal integrity to ensure proper performance . By following these steps—careful planning, proper conduit and cable selection, controlled pulling with lubrication, and adherence to tension and bend radius limits—you can ensure a safe, efficient, and durable fiber optic installation in conduits.