Electrical cable installation is a key link in electrical engineering, and the installation quality is directly related to electricity safety and system stability. The following are the core precautions that must be strictly followed during the installation process.

I. Pre-Installation Preparation

Before construction, carefully check whether the cable model, specification and voltage level meet the design requirements, and inspect the cable appearance for damage, flattening, twisting or scratches on the insulation layer. Use a megohmmeter to measure the insulation resistance. The insulation resistance value of low-voltage cables shall not be less than 0.5 megohms, and high-voltage cables need to meet higher standards. At the same time, confirm that the cable reel is intact and the cable ends are well sealed to prevent moisture ingress.

II. Laying Process Specifications

During laying, the bending radius of the cable must comply with the specifications, usually 10 to 15 times the outer diameter of the cable. The requirement for armored cables can be appropriately relaxed, but excessive bending that damages the insulation layer is strictly prohibited. Cables shall be arranged neatly without crossing and fixed firmly, and the spacing between fixing points generally shall not exceed 1.5 meters. Cables of different voltage levels shall be laid in layers, with high-voltage cables on the upper layer and low-voltage cables on the lower layer. The spacing between strong current cables and weak current cables shall be at least 30 cm to prevent signal interference. The burial depth of directly buried cables shall not be less than 0.7 meters. When crossing farmland or carriageways, the depth shall be increased to more than 1 meter, and protective cover plates shall be laid or conduit protection shall be adopted.

III. Environment and Protection Requirements

Cable laying shall avoid thermal pipelines, flammable and explosive areas. When it is impossible to avoid, thermal insulation or fire isolation measures shall be taken. When passing through floors, walls and fire compartments, fire-resistant sealing materials must be used to tightly seal the holes to prevent the spread of fire. For laying in outdoor or humid environments, waterproof cables shall be selected and moisture-proof sealing treatment shall be completed. The cable trench shall be kept dry, and drainage facilities shall be set up to avoid long-term immersion in accumulated water.

IV. Joint and Terminal Fabrication

Intermediate joints and cable terminals are weak links in installation. The fabrication must be operated by certified professional personnel in strict accordance with the process requirements. When stripping the insulation layer, the conductor shall not be damaged. The crimping die shall match the conductor specification, and the contact resistance after crimping shall be less than 1.2 times the resistance of the conductor of the same length. The complete insulation layer and sealing layer shall be restored at the joint, and waterproof and anti-corrosion protection shall be added. After fabrication is completed, insulation resistance test and withstand voltage test shall be carried out, and the cables can be put into operation only after passing the tests.

V. Safety and Identification

Grounding protection shall be properly implemented during the installation process. The metal sheath, armor layer, joint shell and other parts of the cable must be reliably grounded, and the grounding resistance shall meet the design requirements. Clear and durable identification plates shall be hung at both ends of the cable and at the intermediate joints, marking the cable number, model, specification, start point and end point and other information to facilitate future maintenance and repair. After the construction is completed, as-built drawings shall be drawn to record key information such as cable routing and joint positions in detail.

Summary: Electrical cable installation is a highly professional work. Every link from material selection, laying to joint fabrication, testing and acceptance must strictly follow the specifications to ensure the long-term safe and stable operation of the cable system.