A home electrical panel might not have a main breaker because it's a split-bus panel (common in 1950s-1970s homes), has a main disconnect located elsewhere, or uses a rule of six design 1 with multiple disconnect switches instead of a single main breaker. Knowing your distribution box helps you see which breaker does what. Check and update your labels often. It serves as the central hub where electricity from the utility company is distributed to various circuits throughout the house. It receives power from the main electrical supply and divides it into separate circuits, each. 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.
[PDF Version]