Main and branch bus sections distribute power between incoming, tie, and outgoing breakers. Ring Busbar System: Used in substations for high reliability and lower outage risk. This guide explains how busbars work, common types, key design factors, and how to choose the right busbar for your application. Thermal rating, breaker. A busbar's main function is to conduct and distribute large electrical currents from one source to multiple circuits within an enclosure, acting as a central, high-capacity connection point. As I've seen in the field, the textbook. An electrical busbar is a metallic strip or bar that carries large currents within electrical distribution systems.