Why do wires and cables malfunction?

1. External force damage. Based on operational analysis in recent years, especially in the rapidly developing economy of HaiPudong, a considerable number of cable failures are caused by mechanical damage. For example, non-standard construction during cable laying and installation can easily cause mechanical damage; Conducting civil construction on directly buried cables can also easily damage cables during operation. Sometimes, if the damage is not severe, it may take several months or even years for the damaged area to completely breakdown and form a fault. Sometimes, if the damage is severe, a short circuit fault may occur, directly affecting the safety production of the electrical equipment and the electricity consuming unit;  2. Damping of insulation. This situation is also very common, usually occurring at the cable joints in directly buried or lined pipes. For example, unqualified cable joints and joints made in humid weather conditions can cause water to enter or steam to mix into the joints. Over time, water branches will form under the action of the electric field, gradually damaging the insulation strength of the cable and causing faults;  3. Chemical corrosion. Directly burying cables in areas with acid-base effects often leads to corrosion of the cable's armor, lead skin, or outer protective layer. The protective layer may become ineffective due to long-term chemical or electrolytic corrosion, resulting in reduced insulation and cable failure. Corrosion: The corrosion of cables in the unit is quite severe;  4. Long term overload operation. Overload operation, due to the thermal effect of the current, when the load current passes through the cable, it will inevitably cause the conductor to heat up. At the same time, the skin effect of the charge, as well as the eddy current loss and insulation medium loss of the steel armor, will also generate additional heat, thereby increasing the temperature of the cable. During long-term overload operation, excessively high temperatures can accelerate insulation aging, leading to insulation breakdown. Especially in hot summer, the temperature rise of cables often leads to the first breakdown of weak insulation areas, so there are particularly many cable faults in summer；5. Cable connector failure. Cable joints are the weakest link in cable routes, and cable joint failures often occur due to personnel's direct negligence (poor construction). During the production of cable joints by construction personnel, if there are loose crimping or insufficient heating of the joints in the original network, it will lead to a decrease in the insulation of the cable head, leading to accidents；6. Environment and temperature. The external environment and heat source in which the cable is located can also cause excessive temperature, insulation breakdown, and even explosion and fire；7. Other reasons such as normal aging or natural disasters of the cable body.