For the electromechanical installation industry, wire and cable occupy an important position in the electromechanical installation engineering. The price of copper electric power cables has increased sharply with the increase of copper prices, which has brought great difficulties in engineering cost control. For this reason, the research and application of copper-clad aluminum cables and copper-clad aluminum wire have grown rapidly.
The copper-clad aluminum cable refers to a wire and cable in which a copper core wire is used instead of copper to form a cable main body, and a copper layer of a certain proportion is externally baked. Copper-clad aluminum cables are used for their purposes, mainly copper-clad aluminum cables for power supply.
DC resistivity. The resistivity of the copper clad aluminum wire is larger than that of the pure copper wire, which is about 1.5 times that of the pure copper wire. When the negative value is the same, the weight of the copper clad aluminum wire is about 1/2 of that of the pure copper wire. According to the calculation of the skin effect, the electrical resistivity is equal to that of the copper conductor of the same cross section at a high frequency of 5 MHz or more. The use of copper-clad aluminum conductors serves to reduce electrical resistance. In other applications, by increasing the volume of copper in the copper clad aluminum monofilament and the corresponding process measures, the copper clad aluminum/copper composite conductor meets the DC resistance requirements of the conductor within the upper limit of the outer diameter of the existing conductor of the same specification.
Reduce the AC resistance. The AC resistance is the main basis for the current carrying capacity. Therefore, the copper clad aluminum wire also increases the surface area of the conductor, improves the heat dissipation condition of the cable, and increases the heat dissipation area. The thermal conductivity of aluminum is similar to that of copper under the same material cost. The indicator of AC resistance is much more economical.
Good corrosion resistance: Aluminum is more corrosive than copper. However, since the copper clad aluminum material has been completely metallized, the aluminum is completely covered by copper and will not be contacted by water or air, and fully achieve the same performance as copper. For aluminum conductors, especially in coastal areas, the chloride ions contained in the salt mist in the atmosphere will condense on the surface of aluminum, causing local corrosion around the surface impurities and defects, forming holes, cracks and micro-cells, exacerbating the aluminum conductor corrosion.