What safety device interrupts a circuit when a fault is detected?

The ground fault circuit interrupter (GFCI) is the correct choice as it is specifically designed to prevent electrical shock by monitoring the electrical current flowing through a circuit. If a fault is detected, such as when current leaks from the intended path (for example, if a person inadvertently completes a circuit to ground), the GFCI rapidly disconnects the power to the circuit. This quick interruption helps to protect individuals from serious injury, making it a crucial safety device in areas where water and electricity may come into contact, such as bathrooms and kitchens.

In comparison, a fuse serves to protect electrical circuits by melting when there is an overload, but it does not respond specifically to ground faults. A transformer is used to change the voltage levels in an electrical circuit and does not have a safety function. Meanwhile, a capacitor is primarily used to store electrical energy, filter signals, and improve power factor, and it does not provide any interruption during faults. Thus, the GFCI is uniquely suited for enhancing safety in electrical systems.