This blog post from Tim Benson at Powerful Thinking explores the debate between aluminium and copper cables, focusing on their use in large-scale events and renewable energy projects. Tim highlights that, while aluminium offers advantages such as lower cost, lighter weight, and recyclability, it falls short in conductivity and durability compared to copper. Tim covers the history and types of aluminium conductors, discusses the challenges of using them in event settings and suggests that a hybrid approach might be the future of successful cable installations >>

For those of you who have experienced the delights of dragging 125A three phase copper cables for miles across large event sites, your ears will prick up when I tell you there is a lighter alternative available, namely aluminium. However, before you get too excited, read on, as it will be quite some time before these kinds of cables permeate the event market.

Aluminium cables generally come in four variants – All Aluminium Conductors (AACs), All Aluminium Alloy Conductors (AAACs), Aluminium Conductors Steel Reinforced (ACSRs) and lastly All Aluminium Alloy Conductors Steel Reinforced (AACSRs).

AACs were first used in the United States and Canada as early as the 1830s, principally by utility companies for electrical transmission/distribution networks and for civil construction projects. These cables are manufactured from electrolytically refined aluminium with a minimum purity of 99.7%.

In the 1960s the All Aluminium Alloy Conductor (AAAC) was first developed and used for residential electrical systems, mainly due to a shortage of copper. These cables are made from the Aluminium Alloy 6201, which is high in magnesium and silicon, making it stronger but only moderately heavier than its AAC predecessor.

As post WW2 energy demand grew, there came a need for better long-distance, high voltage transmission lines, which lead to the development of both ACSRs and AACSRs which are now used for extra-long overhead power lines, distribution networks and, most recently, for large scale renewable installations and battery farms. Their steel reinforcement make for a safer overhead transmission system that can span longer distances between pylons and withstand the vagaries of the weather and/or other natural phenomena such as earthquakes.

The main drivers for switching from copper to aluminium conductors are firstly the difference in price, aluminium is generally three to four times cheaper, secondly it is considerably lighter so easier to install for overhead applications and thirdly it is an abundant resource and easily recyclable.  

However, from an electrical point of view, copper retains the highest conductivity of all non-precious metals and, by way of a comparison with aluminium, the latter supports only 61% of copper’s electrical conductivity and has a considerably lower current carrying capacity. This means that an aluminium core needs to be considerably larger in diameter than its copper counterpart in order to effectively deliver the same current. Copper’s tensile strength also makes it more durable and it has a lower thermal expansion tendency than aluminium, meaning it doesn’t expand or contract as much when exposed to heat or cold. Furthermore, aluminium cables are more prone to oxidisation and rust caused by exposure to high levels of salt or water at connection points, which can increase resistance and cause overheating. Temporary distribution networks overlayed across event sites, with their multiple distribution boards daisy chained from the power source to the load, may be particularly prone to failure where the material characteristics of aluminium, such as the thermal expansion or creep and cold flow described above, can cause connections to loosen over time.   

So, keep dreaming up ways of distributing power wirelessly and don’t stop the weight training, as large gauge copper cables will be with us for some time still. If things are going to progress at all, then perhaps we need to look at the work of some battery farm installers who take a kind of hybrid approach to conductor use across their sites, deploying a combination of copper and aluminium when installing their connection points, switchgear and transmission lines.

This article originally appeared in our February 2025 Vision for Sustainable Events newsletter. Sign up to receive monthly event sustainability news, case studies and guest blogs direct to your inbox.