Branch circuits are those conductors that connect from the subpanel to the receptacle, where our subpanel serves as the final overcurrent device. According to the National Electrical Code (NEC), a branch circuit consists of the conductors running between the final overcurrent protection device (like a circuit breaker) and the outlets, lighting fixtures, or. 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. multiwire). Branch device and terminates at another circuits are usually low current (30 amps or distribution center, panelboard, or load less), but can also supply high curre ts. Christian Delbert / Shutterstock.