Aluminum core cable can not be used for a long time
Copper cable has low resistivity, good ductility, good oxygen resistance, large capacity and other advantages, in the cable power supply, has outstanding advantages, aluminum cable and copper cable compared, aluminum cable price is cheaper, in the construction site as a temporary power cable is also very popular, then why can not aluminum cable long-term use?
Aluminum core cable can not be used for a long time
1、The surface of aluminum wire is easy to oxidize in the air
Where the conductor surface is more or less there is film resistance, if the film resistance causes the connection to overheat, overheat and increase the film resistance, the more deteriorated the electrical conductivity, and this type of overheating in the aluminum wire connection is particularly serious. This is because even if the surface of the aluminum wire is scraped clean, it only needs to be exposed in the air for a few seconds to be oxidized and immediately form a layer of alumina film, its thickness is only a few microns, but it has a high resistivity, thus showing a larger film resistance. If aluminum and air contact will have a layer of oxide film, oxide film has a high resistivity, film resistance will cause overheating at the connection, so that the film resistance to further increase, the deterioration of electrical conductivity, aluminum wire overheating, easy to fire.
2、Aluminum has electrolytic corrosion and is easily corroded by hydrogen chloride
For PVC insulated aluminum core wires and cables, another problem may occur, in order to prevent PVC insulation from decomposing hydrogen chloride gas, PVC insulation is added to prevent the decomposition of hydrogen chloride stabilizer. But when the line temperature exceeds a certain temperature (75 ° C), such as the occurrence of line overload or for other reasons to make the connection temperature is too high, the stabilizer can no longer prevent the formation of hydrogen chloride, and hydrogen chloride is to corrode aluminum, which will also increase the contact resistance and fire risk.
3、The expansion coefficient of aluminum is too high
When the aluminum wire is connected with copper or iron, two metal conductors, and through the current, the connection point is heated due to the existence of contact resistance, the three conductors are expanded, but aluminum expands more than copper and iron, so that the aluminum wire is squeezed, the line is cut off and cooled, the aluminum core wire can not be fully restored, so that there is a gap at the connection and loose, and the formation of alumina film due to air. Increase the contact resistance, the next time the heat will be more dramatic, make the situation worse, serious may cause abnormal high temperature or spark spark and ignite a fire.
FOSHAN YUEJIAXIN WIRE ＆ CABLE CO., LTD.
Through the above points, I believe that everyone should know the reasons why aluminum core cables can not be used for a long time. Foshan Yuejiaxin Wire and cable Co., Ltd. was founded in 1999, is a wire and cable R & D, manufacturing and sales enterprises, with advanced automated production and testing equipment, high-quality production management personnel and skilled production technology backbone, escort for stable product quality, the company obtained the national industrial product production license and China's national mandatory product certification certificate ( CCC certificate, to ensure sufficient quantity, so that you 100% rest assured.
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