A distribution boxes acts as the load center and main distributor of electrical power within a building. Also called a distribution board, panel board, breaker panel, or electric panel, it is the central hub in an electrical system that divides incoming power into various. The terms primary, secondary, and tertiary distribution boxes are relative. Let's make an example for clarity: A newly constructed residential area introduces a 10kV power line to a substation. From the transformer's low-voltage side (0. A feeder usually begins with a feeder breaker at the distribution substation. Many feeders leave substation in a concrete ducts and are routed to a nearby pole.