The function of a circuit breaker is to cut off electrical power if wiring is overloaded with current. They help prevent fires that can result when wires are overloaded with electricity.
Fuse boxes house circuit breaker switches. They are typically located in a closet or in a basement. On average, a circuit breaker box contains 12 switches. Large appliances such as a washer or dryer typically have a dedicated switch. Large rooms, such as a living room, usually have an individual switch.
A newer development in circuit breaker technology is ground fault circuit interrupters. Their purpose is to prevent electrical shock to people.