The busbar sizing calculator determines the required busbar dimensions based on the continuous current rating, short circuit withstand, and thermal limits for switchgear assemblies. Other sections have been updated and modified to reflect current practice. Don't worry about its designs and installations, we can use. To calculate Busbar Current, enter the width (mm), thickness (mm), and material carry capacity factor (amps/mm^2). The electrical power system consists of many incoming & outgoing feeder connections, for which busbars are necessary.