UV Exposure: Prolonged sunlight degrades standard plastic jackets, making them brittle. Temperature Extremes: Expansion and contraction can cause stress fractures. So, bending, crushing, or cutting the optical fiber cable beyond. This Recommendation provides a procedure to protect the telecommunication lines using fibre optics against direct lightning discharges to the line itself or to the structures that the line enters. Optical cable monitoring technology. A cable conduit is a protective tube or pipe that is used to encase the fiber optic cable. The conduit can be made of various materials such as PVC, HDPE, or steel.