Copper and aluminium are commonly used as electrical conductors in cables due to their low resistance and excellent conductivity.
Both metals are ductile and relatively resistant to corrosion, making them suitable for various electrical applications. However, their distinct properties make them advantageous for different uses.
High Conductivity: Copper is more conductive than aluminium, with only silver surpassing it among common pure metals. However, silver is more expensive and less robust.
Standard for Conductivity: Copper is the benchmark for electrical conductivity, known as the International Annealed Copper Standard (IACS), with a resistivity of 1.724µΩcm at 20°C, rated at 100% conductivity.
Impurities and Alloys: The conductivity of copper can be affected by impurities or work hardening during processing. While copper alloys can improve hardness, tensile strength, flex endurance, and temperature resistance, they also reduce conductivity.
Thermal Conductivity: Copper's high thermal conductivity makes it better at handling short circuits and dissipating heat.
Availability and Cost: Aluminium is more abundant and offers a more stable and cheaper alternative to copper. The price of aluminium is more consistent compared to the fluctuating cost of copper.
Conductivity: Aluminium is about 61% as conductive as copper. To match the conductivity of a copper conductor, a larger aluminium conductor is required.
Weight: Aluminium is three times lighter than copper, making it easier to handle and ideal for large cables and overhead power distribution.
Thermal Conductivity: Although aluminium has lower thermal conductivity, the larger size of aluminium conductors can mitigate this difference.
Tensile Strength: Copper has roughly twice the tensile strength of aluminium. However, the lighter weight and larger size of aluminium conductors often mean less tensile strength is needed.
Copper-Clad Aluminium: Some conductors combine an aluminium core with a copper exterior. This type leverages the light weight of aluminium and the high conductivity of copper, though the ductility remains similar to aluminium. This conductor type is occasionally used in coaxial cables for its advantageous properties.
In summary, the choice between copper and aluminium conductors depends on the specific requirements of the application, such as cost, weight, conductivity, and mechanical strength. Copper is typically preferred for high-performance, high-conductivity applications, while aluminium is favored for large-scale and cost-sensitive installations.
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