A standard trench for an underground cable is a meticulously constructed environment designed to protect the cable from the ground up. The key components, laid in order from the bottom of the trench to the surface, are:

1. Cable Bedding: A layer of sifted sand or fine soil at the trench bottom.

2. Cable(s): The power cable is carefully laid on the bedding, with adequate spacing between multiple cables.

3. Sand Surround: Another layer of sifted sand covering the cable to provide thermal stability and protection.

4. Mechanical Protection: Heavy-duty plastic or concrete tiles are placed over the sand to act as a physical barrier against future excavation.

5. Warning Marker Tape: A brightly colored tape with a warning message is laid approximately 150-300mm from the surface to provide an early visual alert to future excavators.

6. Final Backfill: The remainder of the trench is filled with excavated soil, compacted in layers, and the surface is restored.