What type of device is a circuit breaker?

A circuit breaker is classified as an overcurrent protection device. Its primary function is to automatically interrupt the electrical circuit when it detects an overcurrent condition, which can occur due to overloads or short circuits. By doing so, it protects the electrical wiring and connected devices from damage caused by excessive current flow.

Overcurrent can lead to overheating and potential fire hazards, so the circuit breaker serves an essential safety role by stopping the flow of electricity before those risks can materialize. This automatic action allows for quick disconnection of the circuit without the need for manual intervention, unlike a manual switch designed for more routine on-off operations.

In contrast, other types of devices listed in the options do not serve the same protective function. A manual switch simply controls the flow of electricity without safety features for overcurrent conditions, a voltage regulation device maintains consistent output voltage but does not address current overloads, and a permanent connection device is used to create lasting electrical connections rather than providing protection against overcurrent.