Proper bedding and backfilling are essential for the long-term reliability and thermal performance of an underground cable. . Incorrect materials or methods can lead to premature failure.

• Bedding: A layer of soft, sifted sand or fine soil is placed at the bottom of the trench before the cable is laid. This protects the cable sheath from damage by sharp rocks or other debris in the soil.

• Backfilling: After the cable is laid, it is covered with a layer of the same sand to create a "blanket" that completely surrounds the cable. This provides a stable thermal environment, allowing the heat generated by the cable to dissipate effectively. Using the correct backfill prevents hotspots and extends the cable's lifespan.