Which device protects against overcurrent and is reset automatically?

The magnetic circuit breaker is designed to protect electrical circuits from overcurrent conditions while having the capability to reset automatically once the fault is cleared. When an overcurrent occurs, the magnetic mechanism in the circuit breaker trips, cutting off the electrical flow to prevent damage to the wiring and connected devices. Once the cause of the overcurrent is resolved, the breaker can be reset easily either manually or automatically, depending on the specific design of the device.

In contrast, fuses operate by melting a metal conductor to break the circuit during an overcurrent situation, but they must be replaced once they blow. Thermal overload relays are specific to motor protection and require manual resetting after tripping. Electronic discharge devices are used for protecting against voltage surges and do not function based on current overload conditions. Therefore, the magnetic circuit breaker is the ideal choice for automatic reset functionality in overcurrent protection.