The main switch, or main breaker, controls the entire electrical supply to the distribution box. It's typically rated for the maximum current capacity of the electrical. A distribution board (also known as panelboard, circuit breaker panel, breaker panel, circuit breaker, electric panel, fuse box or DB box) is a component of an electricity supply system that divides an electrical power feed into subsidiary circuits while providing a protective fuse or circuit. A distribution box, or DB box, is a circuit breaker enclosure. Whether it's a home, office, or factory, the DB box makes sure power. A distribution boxes acts as the load center and main distributor of electrical power within a building.