Attention points in the application of wire and cable products?

1, sprain, pull cable in the installation process, should use the wire release frame, otherwise it is easy to cause twisting and twisting cable sprain and strain, resulting in cable break, short circuit and breakdown. 2, conductor oxidation causes conductor oxidation for many reasons, such as material purity, cooling in the process of processing, more important is the cable after laying the end of the sealing problem, especially the cable with a shielding layer, after laying should be treated with a sealing sleeve, to prevent the exposed end of the water, moisture. 3. Cable breakdown the most direct cause of cable breakdown fault is the breakdown due to the decrease of insulation. There are many factors that lead to the decrease of insulation performance. According to the practical operation experience, it can be summarized as the following situations. 1) external damage. According to the analysis of the operation in recent years, especially in pudong, Shanghai, which is undergoing rapid economic development, quite a lot of cable faults are caused by mechanical damage. For example: cable laying installation is not standard construction, easy to cause mechanical damage; It is also easy to damage the cable in operation when civil construction is carried out on the direct buried cable. Sometimes, if the damage is not serious, it will take months or even years to cause a complete breakdown of the damaged part to form a fault. Sometimes, if the damage is serious, a short circuit fault may occur, which directly affects the safe production of the power supply unit. 2) damp insulation. This condition is also very common, generally occurs in the direct buried or row pipe cable junction. For example: cable joint production is unqualified and do joint in humid climate conditions, will make the joint water or water vapor, time for a long time under the action of the electric field to form water branches, gradually damage the cable insulation strength and cause failure. 3) chemical corrosion. Cable directly buried in the acid and alkali effect of the region, often cause cable armor, lead or outer sheath corrosion, protection layer due to long-term chemical corrosion or electrolytic corrosion, resulting in protection layer failure, insulation, will also lead to cable fault. Chemical: unit cable corrosion is quite serious 4), long-term overload operation. Overload operation, due to the thermal effect of the current, the load current through the cable will inevitably lead to the conductor heat, at the same time, the charge skin effect and steel armor eddy current loss, insulation loss will also produce additional heat, so as to increase the cable temperature. Long-term overload operation, too high temperature will accelerate the aging of insulation, and insulation breakdown. Especially in the hot summer, the temperature rise of the cable often leads to the weak insulation of the cable is the first breakdown, so in the summer, the cable fault is particularly many. 5) cable joint fault. The cable joint is the weakest link in the cable line, the cable joint fault caused by the direct fault of personnel (poor construction) often occurs. Construction personnel in the process of making cable joints, if the joint pressure is not tight, insufficient heating and other original network, will lead to cable head insulation reduction, resulting in accidents. 6) environment and temperature. The external environment and heat source where the cable is located will also cause the cable temperature to be too high, insulation breakdown, and even explosion and fire. 7) normal aging of cable body or natural disasters and other reasons.