How to thread fiber optic cable through heat shrink tubing

Slide the heat shrink tubing onto the fiber optic cable before stripping or terminating, then carefully thread the bare fiber through the tubing while avoiding bends or kinks.Step-by-Step Guide

1. Select the Correct Tubing Choose heat shrink tubing with a pre-shrink inner diameter slightly larger than the cable jacket and a suitable shrink ratio (commonly 2:1 to 3:1) to ensure a snug fit after heating . Measure the cable diameter accurately using a wire gauge or caliper . 2. Slide Tubing onto the Cable Before stripping the fiber, slide the heat shrink tubing back along the cable so it is out of the way of the termination or splicing area . Ensure it is positioned far enough to allow epoxy or connector assembly. 3. Prepare the Fiber Strip the outer jacket carefully, exposing the bare fiber. Handle the fiber gently to avoid bending beyond the minimum bend radius or causing micro-cracks . Work quickly if the fiber is bare, as it can degrade when exposed to air . 4. Thread the Fiber Through the Tubing Gently push the stripped fiber through the tubing, keeping it straight and avoiding twists or kinks. If using a connector or ferrule, insert the fiber into the terminus first, then slide the tubing over the rear body and strength member . 5. Secure and Shrink the Tubing Once the fiber is in place and any epoxy or adhesive has been applied, slide the tubing over the joint or connector area. Use a heat gun or other controlled heat source to shrink the tubing evenly, ensuring a tight seal without overheating . 6. Final Checks Inspect the tubing to confirm it is fully shrunk and conforms to the cable and connector. Ensure there are no gaps, bubbles, or exposed fibers. The fiber should remain straight and undamaged inside the tubing .

Tips for Success

• Always avoid excessive pulling or bending to prevent signal loss or fiber breakage .
• Use adhesive-lined tubing if moisture protection is required.
• Work in a clean environment to prevent dust or debris from contaminating the fiber.
• Practice on a spare cable to get comfortable with threading and shrinking before working on critical fibers. By following these steps, you can safely and effectively thread a fiber optic cable through heat shrink tubing while maintaining fiber integrity and creating a secure, professional finish.