The breaker or fuse box houses the circuit breakers and fuses that protect the circuits in a home or business from overloading. A more formal term for this device is the service entrance panel. The breaker box will typically have a main breaker that can shut off power to all the circuits at once. It also has breakers that control each individul circuit. Some larger customers have multiple sub panels that contain breakers or fuses as well.
Circuit breakers open when the current in a circuit exceeds safe limits. Breakers can be reset by flipping a switch once the cause of the circuit overload has been cleared. The breaker or fuse box is owned and installed by the customer.