1. Selection of wire and cable models
Selection power cable When waiting for wires, use, laying conditions and safety shall be considered; Power cable Overhead insulated cable , control cable, etc; According to different laying conditions, general plastic insulated cable, steel tape armored cable, steel wire armored cable, anti-corrosion cable, etc. can be selected; Flame retardant cable, halogen-free flame retardant cable and fire-resistant cable can be selected according to safety requirements.
2. Selection of wire and cable specifications
Heat generation, voltage loss, economic current density, mechanical strength and other conditions shall be considered when determining the use specifications (conductor cross-section) of wires and cables. According to experience, because the load current of low-voltage power line is large, the section is generally selected according to the heating conditions, and then the voltage loss and mechanical strength are checked; As the low-voltage lighting line has high requirements for voltage level, the section can be selected according to the allowable voltage loss conditions, and then the heating conditions and mechanical strength can be checked; For high-voltage lines, first select the section according to the economic current density, and then check the heating conditions and allowable voltage loss; The mechanical strength of high-voltage overhead lines should also be checked. If users have no experience, they should consult relevant professional units or persons.
3. When the ambient temperature is high or the open laying method is adopted, the safe carrying capacity will decrease, so the larger specification should be selected; When it is used to start the motor frequently, 2-3 specifications shall be selected.
5. The PVC insulated wires in this table are calculated according to the single overhead laying method. If they are laid through pipes or multiple wires, 2-3 specifications larger shall be selected.
6. The above data are for reference only. The model and specification of cable shall be designed and determined by referring to relevant professional data or electrician manual.
7. It is strictly prohibited to drop cables or cable reels with cables from high places during transportation, especially at low temperatures (generally around 5 ℃ and below). Dropping and dropping cables may cause insulation and sheath cracking.
8. Try to avoid storing cables in the open air in an exposed manner, and the cable reel is not allowed to be laid horizontally.
9. When lifting the package, it is forbidden to lift several plates at the same time. On vehicles, ships and other means of transport, the cable reel shall be fixed with appropriate methods to prevent collision or overturning, so as to prevent mechanical damage to the cable.
10. Cables shall not be in contact with acids, alkalis and mineral oils. They shall be stored separately from these corrosive substances. There shall be no harmful gases that damage insulation and corrode metals in the warehouse where cables are stored.
11. During the storage period, the cable shall be rolled regularly (once every three months in summer, and may be postponed in other seasons as appropriate). When rolling, roll the downward storage tray edge upward to prevent the bottom from being damp and rotting. When storing, always pay attention to whether the cable head is intact.
12. The storage period of cables shall be limited to the ex factory date of the product. Generally, it shall not exceed one and a half years, and the length shall not exceed two years.
13. The design and construction of wire and cable laying and installation shall be carried out in accordance with GB 50217-94 Code for Design of Cables of Electric Power Engineering and other relevant regulations, and necessary cable accessories (terminals and connectors) shall be used. The operation quality, safety and reliability of power supply system are not only related to the quality of wires and cables, but also related to the construction quality of cable accessories and lines.
