Wire and cable laying

(1) Laying of conductors

The laying of conductors can be divided into:  ① Exposed laying: The conductor is directly or in the protective body of a conduit or trunking, and is laid on the surface of a wall or ceiling.  ② Concealed laying: wires are laid in protective bodies such as conduits and trunking, and inside walls, ceilings, floors, and floors.

(2) Cable laying

① Buried laying: The buried depth should not be less than 0.7m, and it should be laid under the frozen soil layer, with a 100mm thick soft soil or sand layer laid above and below. The cable should be placed in a wavy manner in the trench, with a length of 1.5% reserved.  ② Cable trench laying: The cover plate of the outdoor cable trench should be 100mm higher than the ground to reduce ground water flowing into the trench. When obstructing traffic and drainage, cable trenches with a covering layer shall be used, and the top of the cover plate shall be 300mm below the ground. Sectional drainage should be considered in the trench, with a water collecting well set every 50m. The slope from the trench bottom to the water collecting well should be no less than 0.5%.  ③ Cable laying through pipe: The inner diameter of the pipe shall not be less than 1.5 times the outer diameter of the cable. The bending radius of the pipe shall be 10 times the outer diameter of the pipe and shall not be less than the minimum bending radius of the cable being threaded. If there is no elbow during cable threading, the length should not exceed 50m; When there is an elbow, it should not exceed 20m; When there are two elbows, a cable well should be provided, and the intermediate junction box of the cable should be placed in the cable well. There should be fire extension facilities around the junction box.