Timely maintenance and repair. For the lines of old buildings, if they are found to be flooded or damp, especially the lines are in disrepair and aging, they should be repaired in time.
Long-term high-load operation, excessive temperature will accelerate the aging of the insulation. Due to the thermal effect of the current, the conductor will heat up when the load current passes through the cable, resulting in the breakdown of the insulation. Long-term overload operation and overload operation,
At the same time, the skin effect of the electric charge and the eddy current loss of the steel armor will also generate additional heat, which will increase the temperature of the cable. During long-term overload operation, the excessive temperature will accelerate the aging of the insulation, resulting in the breakdown of the insulation.
In the hot summer, the temperature rise of the cable often causes the weak insulation of the cable to be broken down first. In summer, there are many cable failures. The cable joint failure is the weakest link in the cable line. The cable joint caused by the construction of the staff Failures occur frequently.
When electrical interference occurs, the control cable is not suitable for circuits with serious consequences, including weak current signal control loops and strong current signal control loops, loops of low-level signals and high-level signals; in split-phase operation,
The weak current control circuit of each phase of the AC circuit breaker should not use the same control cable. If each pair of round-trip wires in the weak current circuit belongs to different control cables, it may form a ring arrangement when laying it. The connection will induce a potential,
Its value may have a great influence on the low-level parameter interference of the weak current circuit. It is recommended to share a control cable for the round-trip wires, the metal shield and the grounding of the shield layer.
The waterproof line protective layer is used to protect the insulating layer from external force damage and moisture intrusion during transportation, laying and use. The protective layer of the paper insulated cable is divided into an inner protective layer and an outer protective layer. The inner protective layer is directly extruded on the insulating layer,
It not only protects the insulating layer from moisture, but also prevents the outflow of insulating oil, and has a certain mechanical strength; the inner protective layer of low-voltage power cables has three kinds of lead, aluminum and poly. The outer sheath protects the inner sheath, increasing the cable's ability to withstand external mechanical forces and corrosion resistance,
The outer protective layer includes an inner lining metal armor layer and an outer covering layer. The inner lining layer protects the metal sheath from the damage of the metal armor layer, and can increase anti-corrosion measures; the metal armor layer can withstand mechanical external force; the outer coating layer Can protect armor metal from external corrosion.