Comparison of Comprehensive Properties of Copper and Copper Clad Aluminum Wires

[China Aluminum Network] According to the different conductors of the internal conductor, there are two main types, one is pure copper material, one is copper clad aluminum material. The copper clad aluminum is: Copper Clad Aluminum, so the copper clad aluminum conductor is often called: CCA conductor. The copper-clad aluminum composite wire was first introduced by Germany in the 1930s, and was subsequently promoted in the United Kingdom, the United States, and France, and was widely used in various fields. The CATV cable in the United States began trialing copper-clad aluminum wire as early as 1968, and consumed 30,000 tons per year. The American countries now use copper-clad aluminum (steel) cables instead of pure copper cables. In recent years, China's copper clad aluminum CATV cable has also begun to be used in large quantities. The country established the industry standard of SJ/T11223-2000 in 2000 and vigorously promoted the use of copper-clad aluminum cables. At present, cable television stations in Shanghai, Guangzhou, Zhejiang, and Liaoning have already adopted copper-clad aluminum cables. The response is good.

Copper clad aluminum is coated with copper on the surface of aluminum or aluminum/steel alloy core material. After drawing, the thickness of copper layer is above 0.55mm. Due to the skin effect of the high-frequency signal transmission on the conductor, the cable TV signal is transmitted over the surface of the copper layer over 0.008 mm. The copper-clad aluminum inner conductor can fully meet the signal transmission requirements, and its signal transmission characteristics are the same as that of the copper wire of the same diameter. Consistent.

Copper clad aluminum and pure copper can be compared in the following three aspects:

Mechanical properties:

Pure copper conductors have higher strength and elongation than copper-clad aluminum conductors, which means that pure copper has better mechanical properties than copper clad aluminum. From the perspective of cable design, pure copper conductors have better mechanical strength than copper-clad aluminum conductors, and are not necessarily required in practical applications. The copper clad aluminum conductor is much lighter than pure copper, so the copper clad aluminum cable is lighter in weight than the pure copper conductor cable, which will facilitate the cable transportation and cable construction. In addition, copper clad aluminum is softer than pure copper. Cables produced from copper-clad aluminum conductors are somewhat softer than pure copper cables.

Electrical performance:

Because the conductivity of aluminum is worse than that of copper, the direct current resistance of copper-clad aluminum conductor is greater than that of pure copper conductor. This has no effect. Main 2014 mid-term exam sprint comprehensive review guide Beijing region test questions Guangdong region test questions Jiangsu region test questions whether the cable will be With power supplies, such as providing power to the amplifier, copper-clad aluminum conductors will result in additional power consumption and more voltage drop if used to supply power. When the frequency exceeds 5 MHz, the AC resistance decay at this time is not significantly different between the two different conductors. Of course, this is mainly due to the skin effect of high-frequency currents. The higher the frequency, the closer the current flow is to the surface of the conductor. Actually pure copper material on the surface of the copper-clad aluminum conductor, when the frequency is high enough, the entire current plating Flowed in the copper material. At 5 MHz, the current flows in a thickness of approximately 0.025 mm near the surface, while the thickness of the copper layer of the copper-clad aluminum conductor is approximately one time greater than this thickness. For the coaxial cable, the transmission effect of the copper-clad aluminum conductor and the pure copper conductor is the same because the transmitted signal is above 5 MHz. The attenuation of the actual test cable can prove this.

The copper clad aluminum is softer than the pure copper conductor and can be easily straightened in the production process. Therefore, to a certain extent, it can be said that the copper clad aluminum cable is better than the cable with the pure copper conductor.

Economical:

Copper-clad aluminum conductors are sold by weight. Pure copper conductors are also sold by weight. Copper-clad aluminum conductors are more expensive than pure copper conductors of the same weight. However, the same weight of copper clad aluminum is much longer than the length of pure copper conductor, and the cable is calculated by length. The same weight of copper clad aluminum wire is 2.5 times the length of copper wire, the price is only a few hundred dollars more per ton. Combined, copper clad aluminum is very advantageous. As the copper-clad aluminum cables are relatively light, the cable transportation costs and installation and installation costs will be reduced, which will bring certain convenience to the construction.

Easy to maintain:

The use of copper clad aluminum can reduce network failures and prevent network personnel from “cutting cores in winter and shearing in the summer” (aluminum strips or tubes). Because the thermal expansion coefficient of the copper inner conductor and aluminum outer conductor of the cable differs greatly, in the hot summer, the outer conductor of aluminum is stretched relatively, and the inner conductor of copper is relatively retracted and cannot fully contact the elastic contact piece in the F headstock; In winter, the aluminum outer conductor shrinks more and the shielding layer falls off. When the coaxial cable is made of copper-clad aluminum inner conductor, the difference in thermal expansion coefficient between it and the outer aluminum conductor is small. When the air temperature changes, the failure of the cable core pulling is greatly reduced, and the transmission quality of the network is improved.

In general, the overall performance of the copper clad aluminum conductor is better than that of the pure copper conductor, which will save the user's cost.

The industry believes that the use of copper clad aluminum wire in the wire and cable industry is also a good way to ease the pressure on the current business. The aluminum wire has a double metal wire drawn from a layer of copper and has a small specific gravity and good transmission properties. It is particularly suitable for use as an inner conductor of RF coaxial cables. Compared with pure copper wire, the density is About 40% of pure copper. The transmission characteristics are better than pure copper wire, and it is an ideal RF coaxial cable branch line inner conductor.