How do you choose a copper busbar for medium voltage switchgear? Start with six factors: rated current, short-circuit withstand, temperature rise, insulation clearance, installation method, and supplier manufacturing consistency. If you only look at current, you can easily buy. Common materials used are copper, aluminum, and a variety of copper alloys. The material chosen, the mechanical constraints and the electrical performance for the specific application determine the conductor's minimum mechanical dimensions (see Conductor Size in the Electrical Design section). Proper sizing ensures the safe current conduction without any overheating, minimizes the voltage drop, prevents mechanical stress and guarantees the regulatory. This guide walks through every step, from material selection and conductor dimensioning to ampacity tables, derating factors, and a fully worked 2000 A example, giving electrical engineers and panel builders a single authoritative reference. What Is a Busbar and Why Does Sizing Matter? For. How do I size a busbar for continuous current rating? Busbar sizing for continuous current starts with selecting a material (copper: 1,700 micro-ohm-cm, or aluminium: 2,800 micro-ohm-cm resistivity) and determining the current density. Busbars are usually specified by their width and thickness, such as: The larger the cross-sectional area of the busbar, the more current it can carry without.
