Select the proper size of heat shrink tubing for your application. Environmental factors and mechanical stress can cause damage and electrical interference, affecting the transmission of data. Heat shrink tubing for fiber. Heat shrink tubing serves multiple purposes in the protection of fiber optic cables within telecom networks: Mechanical Protection: By providing a durable outer layer, heat shrink tubing shields fiber optic cables from physical damage caused by abrasion, bending, and impact. After heating, it can significantly shrink longitudinally and tightly wrap around the parts that were previously placed inside.