Copper-clad aluminum wire
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2008-01-12T00:02:39Z
John a s
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/* Uses */ Link to electrical wiring
'''Copper-clad aluminum wire''', commonly abbreviated as '''CCAW''', is a [[Conductor (material)|conductor]] composed of an inner [[aluminum]] core and outer [[copper]] [[cladding]].
==Uses==
The primary application of this conductor is for high-quality [[coil]]s where weight is an issue, such as the [[voice coil]]s in [[headphones]], portable [[loudspeaker]]s or mobile coils in other applications.
CCA was also used in [[electrical wiring|mains cable]] for domestic and commercial premises. The copper/aluminium construction was adopted to avoid some of the problems with [[aluminium wire]], yet retain some of the cost advantage. It is not used today in domestic 240v installation wiring.
==Properties==
The properties of copper-clad aluminum wire include:
* Lighter than pure copper
* Higher [[Electrical conductivity|conductivity]] than pure aluminum
* Higher strength than aluminum
* Better solderability than aluminum, due to the lack of the oxide layer which prevents solder adhesion when soldering bare aluminum.
* More expensive than a pure aluminum wire; cost relative to pure copper may be hard to establish due to the volatility of copper prices.
==Skin Effect==
Although the [[skin effect]] causes [[alternating current]] to concentrate on the more-conductive copper cladding of the conductor, causing the resistance of the wire to approach that of a pure copper wire at sufficiently high frequency, the skin effect is too weak at audio frequencies to be of importance in typical applications of copper-clad aluminum wire, the [[skin depth]] generally being greater than the radius of the wire (about 0.6 mm at 20 kHz in both Cu and Al). The primary benefits of cladding aluminum with copper rather than vice versa are solderability, as described above, and manufacturability, copper being a metal that can be electroplated with ease, unlike aluminum.
The skin effect is of greater importance in [[copper clad steel]], due to its use in high frequency applications such as coaxial cable, the lower skin depth in steel, and the greater difference in conductivity between the core and the cladding.
== External links ==
*[http://www.shibata.co.jp/etxt/3_f_f2.htm Special Magnet Wires: Copper-clad Aluminum Wire (CCAW)]
[[Category:Copper]]
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