1. Installation and construction of wires and cables
The design and construction of wire and cable laying and installation should be carried out in accordance with GB 50217-94 “Power Engineering Cable Design Code” and other relevant regulations, and necessary cable accessories (terminals and joints) should be used. The operating quality, safety and reliability of the power supply system are not only related to the quality of the wires and cables themselves, but also related to the construction quality of cable accessories and lines.
Through statistical analysis of line faults, the faults caused by construction, installation and connection are often much more likely than the faults caused by the defects of the wires and cables. Therefore, it is necessary to correctly select wires and cables and supporting accessories. In addition to designing and constructing according to the specifications, the following issues should also be paid attention to:
⒈Cable laying and installation should be carried out by qualified professional units or professionals. Construction and installation that do not meet the requirements of relevant specifications may cause the aerial bundled cable sans 1418system to fail to operate normally.
⒉When laying cables by manpower, command and control the rhythm in a unified manner. Every 1.5 to 3 meters, one person carries the cables on their shoulders, pulls them while laying them, and releases them slowly.
⒊When laying cables mechanically, special cable laying machines are generally used and necessary traction tools are used. The traction force is appropriate and evenly controlled to avoid damage to the cable.
⒋Before discharging the cable, check the appearance of the cable and whether the seal is intact. Pay attention to the direction of rotation of the cable reel when disposing. Do not flatten or scratch the outer sheath of the cable. Do not straighten the cable by beating it at low temperatures in winter. In order to prevent the insulation and sheath from cracking.
⒌The bending radius of the cable should be greater than the specified value when laying. Before and after cable laying and installation, use a 1000V megohmmeter to measure whether the insulation resistance between the conductors of the cable is normal, and make appropriate corrections to the measurement results according to the difference in cable type specifications, lengths and ambient temperature. Small specifications (under 10m㎡) (Core conductor) cable should also measure whether the conductor is on or off.
⒍If aerial bundled cables 7870 standardare buried directly, pay attention to soil conditions. Generally, the buried depth of cables under buildings should not be less than 0.3 meters. For soft or complicated surrounding environments, such as farmland, construction sites or roads, they must be buried Depth (0.7~1m) to prevent accidental damage to directly buried cables, and obvious signs should be erected when necessary.