Knots for tying fiber optic cables

Tie a knot in the fiber optic cable's strength member to prevent the fiber from pulling out during stripping or termination.

Step-by-

Step Guide

Prepare the Cable Before tying a knot, ensure the fiber optic cable is clean and free of debris. Identify the strength members (usually Kevlar or aramid yarn) inside the cable, as these are what you will secure, not the delicate glass fibers themselves. Expose the Strength Member Carefully strip a small portion of the outer jacket using a fiber jacket stripper to reveal the strength member.

Avoid pulling on the glass fiber core, as it is fragile and can break easily.

Tie the Knot

Form a loop with the exposed strength member. Pass the working end of the strength member through the loop. Wrap it around the standing part of the strength member and pass it through the loop again.

Pull gently to tighten the knot, ensuring it is secure but not overly tight to avoid crushing the fibers. Secure the Knot for Termination Once tied, the knot prevents the fiber and strength members from slipping when you strip the jacket or attach connectors. For added security, you can double-back the strength member and tape it or use a crimp sleeve if the connector design requires it.

Maintain Proper Bend Radius Fiber optic cables are sensitive to bending. Ensure the knot does not create sharp bends that exceed the cable's minimum bend radius, which could damage the fiber or reduce signal performance.

Tips and Best Practices

Always handle the fiber gently; avoid twisting or kinking the cable. Keep dust caps on connectors until installation to prevent contamination. Practice tying knots on scrap cable before working on live installations to ensure proper technique.

Follow the specific instructions for the connector type you are using, as some connectors may require epoxying or crimping the strength members. By following these steps, you can safely tie a knot in a fiber optic cable, protecting the fiber during handling and ensuring a reliable termination.