Professional Answer: A standard underground cable trench is constructed with multiple layers to ensure the long-term safety and integrity of the cable. The process involves:

1. Trench Excavation: Digging to the required depth and width.

2. Cable Bedding: Laying a 75-150 mm layer of soft, sifted sand or fine soil at the trench bottom to protect the cable from sharp stones.

3. Cable Placement: Carefully laying the cable without excessive tension or tight bends (adhering to the manufacturer's minimum bending radius).

4. Cable Surround/Blanket: Covering the cable with another layer of sifted sand for thermal stability and protection.

5. Mechanical Protection: Placing a physical barrier, such as concrete slabs or plastic tiles, on top of the sand blanket. This is mandatory for HV cables and highly recommended for all installations.

6. Warning Marker Tape: Installing brightly colored warning tape above the protection layer to alert future excavators of the buried cable's presence.

7. Final Backfill: Filling the remainder of the trench with compacted, excavated soil.

Our comprehensive range of underground cable laying equipment and tools simplifies this multi-step process, ensuring precise and safe installation every time.