What is a busbar
A busbar is a solid metallic strip, typically made of copper or aluminium, used for distributing and conducting electricity within electrical systems. Designed to carry large currents efficiently, busbars are commonly found in switchboards, distribution panels, power supplies, and industrial machinery. They also provide connections for various electrical components within a system such as batteries, battery banks and DC equipment. Compared to traditional cables, busbars offer lower electrical resistance, better heat dissipation, and facilitate easy connections for multiple circuits. Their robust construction and efficient performance make them essential for effectively managing power distribution across a wide range of applications.
Form
Busbars are generally flat, and this is intentional, as it maximises the surface area for efficient heat dissipation, which is essential when carrying high currents. The flatness provides a larger contact area, making it easier to bolt or clamp connections securely to other busbars, circuit breakers, cables, or terminals.
Flat busbars are easier to stack, align, and mount in switchgear, distribution panels, and similar assemblies. This simplifies the overall installation process and improves accessibility for maintenance or future modifications.
What is the purpose of a busbar?
The main purpose of busbars is to distribute electricity in systems that require high current. They are commonly found in various industrial applications, including facilities, power plants, and substations.
Busbar materials
Busbars come in various materials, and the choice of material goes beyond just aesthetics. It depends on several factors, including availability, application, budget, the environment in which the busbars will be used, and the ease of importation. When selecting a material, it’s important to consider the unique challenges and requirements of each application.
Aluminium
Lightweight
Using aluminium as a busbar material is advantageous for applications where weight is a factor. Aluminium busbars are lightweight, which is essential for installation, logistics, and avoiding the need for additional materials such as concrete or spacers to hold the busbars in place.
Many users opt for aluminium busbars instead of copper due to logistical advantages. Aluminium’s lighter weight makes it not only easier to transport but also simplifies the installation and handling processes. This practicality can significantly improve efficiency and reduce costs in various applications.
Budget and Cost
Using aluminium busbars is usually less expensive than copper busbars at nearly every stage of the supply chain. From the lower price of raw aluminium, abundance, to reduced production and installation costs, they offer a practical solution for budget-conscious projects. As already mentioned, aluminium’s lighter weight also contributes to savings in transport and handling. Together, these factors result in significantly lower upfront costs, making aluminium busbars a popular choice for large-scale installations, infrastructure projects, and any application where controlling costs is a key concern.
Copper
Copper is the traditional choice for busbars and is widely used across many applications due to its proven performance. It offers several advantages over alternative materials, including:
Conductivity
Among all the benefits, the standout feature of copper is its remarkable electrical conductivity, making it a popular choice for busbars. It outperforms aluminium in this area, which means less energy is lost as heat and more power gets to where it’s needed. This makes copper busbars especially useful in high-current systems where efficiency and reliability are non-negotiable.
Durability
Copper busbars are known for their impressive durability, with many sources indicating a lifespan of 25 to 50 years when properly maintained. In controlled, clean, indoor environments, busbars can easily achieve these longevity benchmarks. Conversely, those exposed to harsh conditions, such as high levels of corrosion, oxidation, vibrations, and extreme temperatures, may not last as long. However, applying protective coatings such as tin, nickel, or epoxy, and using proper insulation, can greatly extend their service life. With regular maintenance, even busbars operating in demanding environments can remain reliable for decades.
Heat
In extreme environments where heat is a significant factor, copper busbars are superior to aluminium because copper’s higher melting point and greater mechanical strength make it far less prone to deformation or failure. This makes copper the preferred material for busbars in high-temperature, high-reliability applications
Surface treatment
In applications where the surface treatment of copper busbars is easier to electroplate than that of aluminium. Copper electroplating involves simply cleaning the copper part and submerging it in an electrolyte bath, where copper ions are deposited electrochemically. This process is straightforward and commonly used in industry. In contrast, other materials, such as aluminium, may require specialist pretreatment cycles, different aluminium grades, and more effort towards reducing the risk of galling and improving corrosion resistance.
Enhancing the performance of busbars
Busbars generally have higher initial costs due to the complexity of engineering, design, and fabrication; a portion of this investment is directed towards advanced coatings and treatments.
These coatings substantially improve the performance, durability, and safety of busbar systems, justifying their use in demanding electrical distribution environments. They provide lasting benefits in terms of operational reliability and reduced maintenance, making busbars a cost-effective solution for applications where durability and performance are crucial.
In applications where environmental factors, such as moisture and dust, lead to corrosion and oxidation, which reduce the safety, durability, and performance of busbars. Busbars without protection are at risk from this, highlighting the importance of surface coatings. Surface treatments such as electroplating and metal finishing act as protective barriers against these environmental factors.
However, producers and manufacturers do not have to worry as technical support for surface coatings and treatments for busbars is widely available from metal finishing companies.
Surface coatings for busbars
There is a wide variety of coatings for busbars depending on the desired application and the environment the busbars will be operating in. They range from:
Gold plating
Gold plating is Ideal for busbar applications where the components will be prone to corrosion and oxidation. Gold plating provides the highest corrosion resistance, increasing the durability of busbars. As a result, gold plating is a trusted electroplating process for busbars, providing superior protection, stable performance, and increased longevity for electrical components.
Nickel Plating
Nickel plating gives busbars a distinct, shiny appearance, which is advantageous for applications where identification and visual appeal are important. This can help in aiding in identification and offering a visually attractive finish, which can be desirable for exposed or labelled busbar assemblies.
Beyond aesthetics, nickel plating is valued for its hardness, wear resistance, and moderate corrosion resistance, significantly enhancing the service life of busbars. While nickel enhances the mechanical durability of busbars, its primary metallurgical role in power systems is as a robust barrier and underlayer, particularly beneath precious metal topcoats like gold, to prevent corrosion and improve finish uniformity.
Nickel plating can also be used as a base layer in cases where there may be concerns about thickness or uniformity of plating, making the base layer vulnerable to corrosion or wear and tear. For example, gold-plated busbars can be paired with an underlying sacrificial base nickel coating for added protection.
These combined properties make nickel plating a versatile and reliable choice in electrical, automotive, and industrial busbar applications
Tin Plating
For applications where galling is a concern, coating busbars with a layer of tin offers a practical solution. Its naturally lubricious properties help reduce friction and wear between metal surfaces, making connections more durable over time.
While busbars can involve high upfront costs due to engineering and surface treatments, tin plating offers a cost-effective alternative to more expensive finishes, such as gold or silver. Despite being more affordable, it still offers strong corrosion resistance, reliable electrical conductivity, and a range of visual finishes, such as bright or dull, to suit different requirements. The oxide layer that forms on tin remains thin and conductive, unlike copper, which oxidises and degrades performance.
Tin-plated busbars also tend to require less maintenance and fewer replacements throughout their service life, making them a dependable option across a range of commercial and industrial applications.
Silver Plating
For high-performance busbar applications, silver plating is an ideal choice. Silver has the highest electrical conductivity of all metals, enabling exceptionally efficient power distribution and transfer. Although silver is not as corrosion-resistant as gold, it still offers relatively high resistance to corrosion and oxidation in most environments, although it may tarnish in the presence of sulfur-containing compounds.
Silver plating on busbars ensures low and stable contact resistance in high-current connections, helping to reduce maintenance, increase system uptime, and minimise the risk of electrical failure. This makes silver plating especially well-suited for critical busbar connections and joints, such as those found in switchgear, circuit breakers, and power distribution panels.
Silver and tin plating enhances solderability and create reliable electrical connections, resulting in stronger and longer-lasting contacts.
This article provides an overview of busbars, including their use cases, benefits, and material selection, while also highlighting the advantages of coatings such as silver and tin.