It covers topics such as busbar material selection criteria, sizing calculations, installation practices, and good practices for bending, punching holes, making connections, and applying anti-corrosion treatments. This guide presents and illustrates all the best practices to apply when building low-voltage switchboards, in compliance with IEC standards 61439-1 and -2. The application of these rules means strict compliance, not only with applicable regulations and standards, but also with manufacturers'. The object for this guide is to provide an easily understood document, aiding interpretation of the requirements to which Busbar Trunking Systems are designed and how they should be safely installed and used in service. In most assemblies you will find horizontal main bars, vertical risers, neutral and equipment-ground buses, and purpose-designed. Designing a bus bar system requires balancing electrical, thermal, mechanical, and safety considerations. Current Carrying Capacity The bus bar must be sized to carry the. IEC 61439 is a standard developed by the International Electrotechnical Commission (IEC) that covers design verification for low-voltage electrical products and assemblies. These assemblies are crucial components in.