COPPER-CLAD ALUMINIUM

Growing Interest in CCA

Over the last year in many markets there has been increasing interest in copper-clad aluminium (CCA) wires as a possible way of reducing material costs in certain types of cable. Several Chinese companies have perceived a potential market opportunity and installed equipment for production of CCA wire. CCA consists of copper cladding surrounding an aluminium core. The most common grade of CCA is 10% CCA, meaning that it contains 10% copper by volume: only 5% of the radial thickness of this grade of CCA is copper and the rest is aluminium, though it contains approximately 43% copper by weight, since copper is a much denser metal than aluminium. 10% CCA has an overall conductivity of 65% IACS, i.e. 65% of the conductivity of an all copper conductor of the same cross-section, but its average density is only 37% of copper.

CCA Promoted as Low Cost

CCA suppliers promote the material as offering most of the advantages of aluminium, such as having lighter weight and lower cost than copper, but without the main perceived disadvantages of aluminium. With CCA they argue that there is no need, as there can be with aluminium wires used in LV energy cables, for specially designed accessories to give reliable electrical connections. Though CCA appears to have a significant cost advantage over copper because its main constituent is the cheaper metal aluminium, in practice some of this advantage is eroded by the higher fabrication costs of CCA, as cladding processes are more complex than conventional wire-drawing. Traditionally, in developed economies CCA has not been widely used as a low cost alternative to copper: for example, some lightweight aircraft cables using CCA actually cost more than their copper equivalents. This situation is, however, changing due to the sustained high level of copper prices and increased production volumes of CCA that are becoming available from China.

CCA Used for HF Applications

One of the main traditional applications of CCA is in communication cables as the central conductor of coaxial cables. CCA is also sometimes used in enamelled magnet wire when low weight is critical (e.g. coils for headphones and aircraft instruments). Due to the skin effect, which means that high frequency signals are mainly transmitted in the surface layers of a conductor, CCA is usually used for carrying high frequency signals. For these applications (e.g. coaxial cable) the higher DC resistance of the aluminium core is not so important. Indeed, in really high capacity, very high frequency coaxial cables signal transmission within the central core of the conductor is so negligible that hollow copper tubes, not solid wires, may be used.

CCA Producers Consolidate

There are several producers of CCA conductors in China, but the largest of these is Fushi International, a Chinese company that is listed in the US. The main producer of CCA (and also copper-clad steel used in coaxial cables and drop wires) conductors outside China is Copperweld Bimetallics with its main production facility in the US and a smaller one in the UK. CommScope is also a producer of CCA conductors in the US. During 2007 Fushi International acquired Copperweld, making this company a major global player in this niche cable-making material.


New Applications for CCA?

Apart from the traditional applications of CCA, in coaxial cables and some specialised magnet wires, it has also been promoted for other applications such as LAN cables. Some Chinese producers have offered LAN cables containing CCA, rather than copper wires, at prices significantly lower than conventional LAN cables. We understand that these low cost substitutes would not meet all the technical performance specifications required for LAN cables used in business premises, but they might find an application at the lowest end of the LAN cable market, such as home networks. It has also been suggested that CCA can be used more widely in building wire or LV power cable, but there would be major hurdles to be overcome in terms of getting this alternative material accepted in building codes and wiring regulations.

Copper Wire Scrap Recycled

Copper wire scrap normally trades at only a modest discount compared to copper cathode, since, so long as the purity of the scrap is guaranteed, it can be easily recycled with minimal need for further refining. However, guaranteeing the purity of the scrap in-feed material is critical, since any contamination by other elements could potentially lead to an expensive batch of substandard production. Some copper wire scrap is generated during the cable production process, while some is recovered from cables at the end of their life. There have always been good economic arguments for recycling copper wire scrap, but there is an even stronger need for maximising scrap recovery when metal prices are as high as they are currently.

Potential for Scrap Contamination

Tinned copper wire can be readily identified, segregated and diverted through its surface appearance, but scrap CCA wire is potentially much more of a problem. Superficially CCA wire appears to be the same as copper wire: it is necessary to look at the wire in cross-section to be sure that a wire is pure copper and not CCA. The aluminium content of CCA is a big potential hazard as it could contaminate a batch of clean copper wire scrap, and careful checking would be needed to avoid this problem. This has not been a major issue while CCA wire has been used only in niche applications, but it would become a more serious problem if CCA were in wider use. In Europe a major copper producer and scrap recycler has already experienced problems with CCA contamination of its scrap feedstock. In China there has been caution about approving CCA more widely because of concerns about CCA scrap.

Little Value in CCA Scrap

On the other hand, CCA has sometimes been promoted on the grounds that it has lower scrap value than pure copper because it cannot be recycled as readily as copper! The outer copper coating of CCA wire cannot be easily stripped away from the aluminium core. Thus cables containing CCA should be less attractive to thieves, as the scrap value is much lower than copper, though it may be optimistic to expect criminals to be so well informed. There are some potential outlets for scrap CCA, such as an in-feed material for coin blanks that use alloys containing copper and aluminium, so a market for CCA wire scrap could develop if the material came into wider use.