Which device automatically stops electrical current when a fault is detected?

Circuit breakers are designed to automatically stop the electrical current when a fault, such as an overload or short circuit, is detected. They function as a safety device by breaking the circuit and preventing excessive current from causing damage or posing a risk of fire or electric shock. This automatic operation allows circuit breakers to reset after the fault has been resolved, making them more convenient for regular use compared to other devices that may need to be replaced after failure.

Fuses and Ground Fault Circuit Interrupters (GFCIs) also serve to protect against faults, but they operate differently. Fuses provide overcurrent protection by melting and breaking the circuit when the current exceeds a certain level, requiring replacement after a fault. GFCIs specifically detect ground faults that could result in shock, interrupting the current flow, but are designed for specific applications rather than general overcurrent situations. Transformers, on the other hand, are electrical devices used for altering voltage levels and do not have a protective function related to discontinuing current under fault conditions.

Together, these distinctions clarify why circuit breakers are the most suitable answer to the question regarding automatic interruption of electrical current due to faults.