In residential wiring, what purpose does a circuit breaker serve?

In residential wiring, a circuit breaker is primarily designed to protect against overcurrent, which occurs when the current flow exceeds the safe limits for the wiring, potentially causing overheating and fire hazards. The circuit breaker acts as an automatic switching device that interrupts the electrical circuit in the event of an overload or short circuit. When it detects excessive current, it trips and cuts off the electrical supply to prevent damage to the wiring and connected devices, ensuring safety in the electrical system.

The other options, while related to electrical systems, do not accurately describe the primary role of a circuit breaker. For example, a circuit breaker does not increase voltage; that function is typically associated with transformers. Its role is not to serve merely as a switch for lighting; switches perform that function. Additionally, while measuring electrical energy is crucial for monitoring consumption, it is typically done by devices like wattmeters or smart meters, not circuit breakers. Thus, the correct response emphasizes the essential safety function of a circuit breaker in residential wiring systems.