How to thread optical fibers through a corrugated pipe

Use innerducts, proper lubrication, and careful bundling to thread optical fibers through corrugated pipes efficiently and safely.

Preparation and Tools

Before threading fibers, prepare the cable and conduit: Use innerducts (corrugated or smooth-walled) to protect fibers from abrasion and reduce pulling tension. Ensure the fiber ends are capped or taped to prevent moisture ingress and damage. Gather pulling tools such as fish tape, cable pullers, and approved cable lubricants.

Avoid liquid detergents, which can damage polyethylene jackets.

Bundling Fibers

Arrange fibers neatly and bind them with optical fiber binding tape to prevent crossover and tangling. Cut tape to the appropriate length, wrap around the bundle, and secure the hook and mat sides snugly. Keep bundles small enough to maintain the minimum bend radius of the fiber, typically 15 times the cable diameter.

Threading Techniques

Use a figure-eight coil when unrolling fiber to prevent kinks and twisting, especially for long runs. For corrugated pipes, consider pulling one fiber at a time or small bundles to reduce friction and tension. Apply approved cable lubricant sparingly inside the pipe to ease pulling.

If the innerduct stretches during installation, plan for extra slack to maintain proper bend radius and avoid stress.

Additional Tips

Avoid pulling multiple cables over existing ones to prevent entanglement. Secure the innerduct at manholes or junction points to prevent twisting or flattening. For tight or long runs, a pulling rope or fish tape can guide the fiber through the corrugated pipe efficiently.

Always handle fibers carefully to prevent breakage and dispose of scraps safely. By following these steps—preparing the cable, bundling fibers, using innerducts, applying proper lubrication, and carefully pulling—you can thread optical fibers through corrugated pipes efficiently while minimizing the risk of damage.