Cable Conductors: Copper vs. Aluminium
The purpose of cable conductors is to conduct electric current or electron flow.
The primary consideration when selecting a material for use as a conductor is resistivity, which is also known as specific electrical resistance. The lower the resistivity, the lower the conductor loss.
Mechanically, a pliable material is required to allow for easy processing. It must be relatively strong, non-corrosive, and have a reasonable degree of flexibility. Flexibility can of course be improved by stranding or bunching conductors.
Note: Solid conductors are typically used within fixed installations and offer 25-50% improvement in attenuation/resistance over stranded or bunched conductors.
Material
The wire & cable industry has a vast choice of conductor materials that can all carry signals when used in specific environments. Options include Copper, Tinned Copper, Copper Clad Aluminium, Copper Clad Steel, Silver Plated Copper, and Aluminium. The most commonly used are Copper and Aluminium.
Copper
Copper is the most extensively used conductor material due to the following features and benefits:
- Good electrical conductivity: 1.724µΩcm
- Good mechanical connection
- Good resistance
- Easy processing capability
- Environmental resistance
- Solid tensile strength
- Good thermal conductivity and expansion properties
- Can be tinned to aid high temperature installation and soldered connections
- Smaller diameter
Copper has limited disadvantages, which include:
- Potential for oxidisation when exposed to atmosphere due to a reaction with oxygen and moisture. Increase in resistance at high frequency if conductors are tinned. This is due to the higher resistivity of tin, which when sitting on the surface of the copper carries most of the current.
- Copper market prices can be erratic due to LME (London Metal Exchange) fluctuations.
Aluminium
Aluminium is the second choice behind copper in most commonly used conductors, offering fewer advantages as follows:
- Cost is substantially lower than copper and pricing tends to be more stable
- Lightweight at 30% of copper weight, which makes it more suitable for large overhead power installations
- Good VHF/UHF performance
- Easy to process
- Aluminium has more disadvantages than copper:
- Environmental deterioration
- Metal is prone to creep, which can increase risk of fire if not inspected regularly
- Only 61% as conductive as copper
- Larger conductors are required to match copper conductivity, increasing cable dimensions, which then requires more insulation material to be used to adequately cover the conductor
- Poor tensile strength
Conclusion:
In summary, when determining whether a copper or an aluminium conductor is right for your project it’s not necessarily a straightforward decision. Every project has different requirements. Therefore, several key considerations should be made in combination when evaluating your options, including signal loss, material cost, install time, safety, and long-term maintenance.
For more information about copper and aluminium-based conductor cablesalk to our dedicated Webro Team for expert advice, sales@webro.com or call 0115 972 4483. Or you can get in touch.
