Copper and aluminium are the two most common conductors used in electrical equipment, including Busbar trunking systems.
Copper is one of the oldest known metals, recognised today for its strong ductility, tensile-strength, thermal-conductivity, and thermal-expansion properties. Traditionally, copper was the conductor of choice for busbar trunking systems. However, in more recent years the use of aluminium conductors has become more prevalent in the global busbar trunking market, offering certain advantages that copper cannot compete with. As a result, many busbars manufacturers now offer both copper and aluminium solutions, affording engineers more choice. Therefore, it is important for engineers to understand the true benefits and drawbacks of each material as a conductor in busbar trunking applications to facilitate smart decision making.
Conductivity
aluminium has 62% the conductivity of copper, which often leads specifying engineers to disregard aluminium as a viable conductor for busbar trunking systems. The lower conductivity of aluminium means that a much larger size of conductor will be required to match current carrying capacity of a copper conductor.
However, aluminium can be as much as 70% lighter than copper. Even when taking the larger size of and aluminium system, the busbar will still weigh significantly less than a copper system of equal conductance. The reduced weight of aluminium conductors can create cost savings in many areas, with fewer supports required to secure the busbar, less manpower required for installation and reduced transportation costs. Similarly, when you compare conductivity per weight, you will find that aluminium is actually 50% more conductive per kg.
Granted, the larger overall dimensions of an aluminium busbar system may be restrictive in certain applications such as small buildings or underfloor applications. However, if size is not an obstacle for your specification, but weight restrictions do apply, aluminium may be the best choice to maximise conductivity whilst minimising cost.
Ratings
When compared by volume, copper outperforms aluminium when it comes to electrical ratings. Boasting a lower electrical resistance, lower power loss, lower voltage drop and higher ampacity. All of which contribute to the electrical efficiency of the busbar trunking system.
However, when compared by weight, aluminium is more electrically efficient. Again, this can be attributed to aluminium having a density 70% lower than copper, making it the perfect choice where busbar sizing is a non-issue.
Price
The price of copper is much more volatile than aluminium, heavily influenced by consumer demand amongst other political and economic factors. According the London Metal Exchange, the price ratio of copper to aluminium is currently over 3:1, representing a significant cost difference.
As a result, aluminium allows specifiers and contractors to compile cost forecasts with more accuracy and has consistently provided huge project cost savings passed on from the busbar manufacturers. This presents a huge advantage in todays highly competitive power distribution market where cost has become a key concern for all parties involved.
Environmental Sustainability
Whilst both aluminium and copper are 100% recyclable, differences in how each metal is recycled and mined/extracted impact their environmental sustainability.
When considered on a percentage basis, aluminium is the most recycled industrial metal with 75% of aluminium ever produced still in use today. Comparing this to the 65% of copper that is still in use or available for use. Similarly, the recycling process for aluminium uses only 5% of the energy required for primary production and releases only 5% of the associated emissions. Again, although copper can also be recycled at a reduced environmental cost, the process is different, using a 15% of the energy required to mine and extract the same copper. With this in mind, aluminium is arguably a more sustainable option for busbar trunking conductors as it is less reliant on non-eco mining and extraction processes and can its recycling processes produce less energy waste.
Conclusion
Although the debate on which metal is the most suitable is subjective to individual to specifications and project limitations, we hope to have shed some light on the benefits and drawbacks of both copper and aluminium busbar trunking conductors that will aid your future decision making.
