Bus bars - what are they and what are they made of?

So what exactly are these components, what are their functions and what materials are they made of?

What are bus bars?

Bus bars, also known as power rails or busbars, are components, usually made of copper and aluminium, that are a very important part of the electrical circuits in various types of equipment, switchgear and controls. As part of a circuit or power network, they provide the connection between the power source and the load - their primary function is to carry high energy current.

A properly designed and constructed bus bar system offers many benefits:

• It saves considerable space in the switchgear or panel, especially when compared to power equipment connected by traditional wiring;
• allows for easy assembly - systems or electronic components are mounted directly on the bus bar, which streamlines the assembly process and also allows for easier maintenance of the entire installation, reducing maintenance costs;
• Prevents overloads and surges in the electrical installation, ensuring safe and reliable machine operation;
• Allows electrical cables to be easily added, removed or relocated without the need for additional cables, allowing the installation to adapt more quickly and flexibly to changing needs and minimising the risk of potential faults or interruptions.

Bus bars are used in switchgear, transformers, converters, inverters and control cabinets in many industries due to their very good electrical conductivity and numerous advantages. They are not only used in the electrical industry, but also play an important role in railway traction, marine, chemical and heavy industry, high current and storage technologies, renewable energy sources or mechanical engineering.

 

Busbar types

The basic division of bus bars is between single bus bar systems (consisting of a single conductor) and double or triple bus bar systems (consisting of two or more conductors that are separated).

• Single bus bar systems are commonly used in various electrical installations and provide an economical way of distributing power. In this case, a single layer of conductors can be placed on a single busbar.
• Double, triple bus bar systems with auxiliary systems - have at least two or three layers, allowing the number of circuits on a single bus bar to be increased. Their use allows efficient use of space and increased installation flexibility.

It is worth noting that busbars can vary in geometry - shape, dimensions and design. They can be bent, twisted or profiled to suit different mounting configurations. It all depends on the equipment they are installed in and the current and voltage they need to carry.

What materials are bus bars made from?

The most commonly used bus bars in various industries are copper. This is one of the best conductive materials, has a low coefficient of thermal expansion and is resistant to corrosion and most organic chemicals.

Aluminium bus bars are also widely used.

Electris uses several different non-ferrous metal alloys in the production of bus bars, depending on the application and the technical specifications received from the customer. The company manufactures bus bars from copper flat bars or copper sheets of the Cu-ETP or Cu-OF types, as well as aluminium sheets of the AW-1050 or AW-5754 types.

Current carrying capacity of busbars

The current carrying capacity of bus bars is the maximum value of current that can flow through them without risk of damage. This is a very important parameter to consider when designing busbars for a particular piece of equipment - exceeding the current carrying capacity can lead to overheating of the bus bars, with a consequent reduction in their service life and even failure of the entire installation.

Laminated bus bars

In order to avoid risks and to ensure that every bus bar in a power distribution system or control cabinet fulfils its purpose and ensures the uninterrupted operation of the entire system, it is worth choosing laminated bus bars. Thanks to their larger cross-section, they provide increased current carrying capacity and, on top of this, improve electrical properties (lowering inductance and impedance and increasing capacitance). Laminated parts are also ideal for devices such as wind turbines, for example, due to their strength, stability and ability to conduct large amounts of electrical current. Laminated bus bars are characterised by their robust construction, which enables them to withstand the harsh weather conditions (moisture, salt water), strong vibrations and dynamic loads that can occur in wind turbines.

Laminated bus bars are also used in many other areas - wherever ensuring the stable flow of electrical current is crucial to the proper functioning of control and automation systems.

Busbar protection - what does it look like?

The protection of bus bars, e.g. against short-circuits or mechanical damage, is also crucial in terms of the reliability and safety of the electrical installation. At Electris, we use, among other things, the following for this purpose:

• powder coating technology with epoxy paints to produce an insulating coating with suitable physical, aesthetic and functional properties,
• application of heat-shrinkable sheaths,
• in the case of laminated busbars, we use approved insulating materials such as GPO3, FR-4, Kapton®, Tedlar or Exolon.

It is very important in the case of bus bars that appropriate tests are carried out: among others, voltage tests - High Voltage - HV (30kV) and Partial Discharge (PD) - which provide guarantees of product quality and appropriate functionality. They make it possible to verify the integrity of the insulation between the different layers of bus bars and to assess their resistance to overvoltage and damage.

An insulated bus bar will perform well in harsh environments and ensure the safety and reliable operation of the entire installation.

Bus bar selection

At the stale of selecting bus bars for a particular installation, it is worth paying attention first of all to the requirements of the specific installation and the environmental conditions. In this respect, the shapes, dimensions or number of bus bar layers can be determined. Aspects such as the current carrying capacity and the material of the component are also key.

At Electris, we are specialists in manufacturing dedicated non-ferrous metal components for various solutions. We produce copper and aluminium bus bars, laminated bus bars, connectors and many other components. Our R&D and New Products Implementation departments will assist you in selecting the appropriate component processing technologies. Please do not hesitate to contact us to place an order or obtain additional information.