Primary distribution systems consist of feeders that deliver power from distribution substations to distribution transformers. Many feeders leave substation in a concrete ducts and are routed. A power distribution box (also called PDU or distro) directs electricity from a main source to multiple circuits. It acts like a hub or traffic controller, managing power flow to different areas or devices. Today, electrical systems are essential for homes and industries. 4kV), power is distributed to a main distribution panel (primary distribution box). This guide will cover electric distribution boxes, their basics, types, functions. Electrical distribution boxes are used in commercial and residential buildings and are part of the electrical system, also known as switchboards.