Cable laying is a critical step in electrical construction, and the installation quality directly affects the service life and operational safety of the cables. Below are three major precautions that must be strictly adhered to.

‌一、Bending Radius and Mechanical Protection

During cable laying, the bending radius is the primary parameter to control. An excessively small bending radius can cause cracks inside the insulation layer, leading to deformation or even fracture of the copper conductor due to stress, which may easily result in dielectric breakdown after long-term operation. The bending radius requirements vary depending on the cable type: for unarmored cables, the bending radius should be no less than 10 times the cable's outer diameter; for armored cables, no less than 12 times; and for mineral-insulated cables, no less than 6 times. Special guide wheels or pulleys should be used during laying to prevent the cable from being dragged and rubbed against the ground or supports. When cables are pulled through conduits, the inner diameter of the conduit should be no less than 1.5 times the cable's outer diameter, and the inner wall of the conduit should be smooth and free of burrs. Protective cover plates or warning tapes must be laid above direct-buried cables. When crossing roads or building foundations, protective sleeves must be installed to prevent damage to the cables from future excavation work.

‌‌二、Environmental Control and Protection

The laying environment is crucial to the long-term operational reliability of the cables. Cable trenches or shafts should be kept dry, with drainage slopes set at the bottom, and sumps and drainage pumps installed at the lowest points to prevent long-term water immersion of the cables. Cables must not be laid parallel to or crossing heat pipelines, oil pipelines, gas pipelines, etc. If this cannot be avoided, thermal insulation or isolation measures must be taken, maintaining a clearance of no less than 1 meter. In corrosive environments (such as chemical plants or coastal salt-spray areas), corrosion-resistant sheathed cables should be selected, and cable supports and trays should be treated with anti-corrosion coatings. Holes penetrating fire compartments, floors, and walls must be strictly sealed with fire-blocking materials to prevent the spread of fire along the cables. In addition, there are ambient temperature requirements for cable laying: PVC-insulated cables should not be laid at temperatures below 0°C, and XLPE-insulated cables should not be laid below -10°C. Preheating of the cables is required for construction in low-temperature environments.

‌‌三、Standardized Fixing and Arrangement

After laying, cables should be arranged neatly and fixed firmly to avoid chaotic crossing. For horizontally laid cables, fixing points should be set at the beginning and end of the cable, at bends, and on both sides of joints; for vertically laid cables, the spacing between fixing points should not exceed 1 meter. When cables of different voltage levels are laid in the same trench, they should be arranged in layers according to voltage, with high-voltage cables on the upper layer and low-voltage cables on the lower layer, separated by partitions in between. Control cables and power cables should be laid on separate sides or in separate layers with a spacing of no less than 30 cm to prevent strong electrical interference with weak signals. Special cable clamps or tie wraps should be used for fixing; direct binding with iron wire is prohibited to avoid damaging the sheath. The number of cables in the same channel should not be excessive to prevent poor heat dissipation leading to elevated operating temperatures. When multiple cables are laid side by side, the current-carrying capacity correction factor must be considered, and the rated current-carrying capacity should be appropriately reduced.

‌Summary: The three core aspects of cable laying—bending radius and mechanical protection, environmental control and protection, and standardized fixing and arrangement—are all directly related to the safety and lifespan of the cable system. Strictly controlling these three aspects during construction is essential to ensure the long-term and stable operation of the cables.