The main switch, or main breaker, controls the entire electrical supply to the distribution box. Circuit. The distribution box (DB box) helps safely and efficiently distribute electrical power. It integrates power distribution, protection, and monitoring capabilities, and is responsible for distributing power to entire commercial or residential. 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.