Primary: The main distribution panel, supplies power from the transformer. It acts like a hub or traffic controller, managing power flow to different areas or devices. Key components include circuit breakers, fuses, bus bars, and internal wiring for safety and. From the transformer's low-voltage side (0. From there, it is routed to individual building distribution boxes (secondary distribution boxes), which subsequently supply power to unit-level distribution boxes. AC power distribution systems are designed to provide electricity to users in the residential, commercial, and industrial sectors in a safe, efficient, and reliable manner.