What device is required to protect circuits that are installed in locations prone to moisture?

To protect circuits installed in areas that are prone to moisture, a ground fault circuit interrupter (GFCI) is essential. GFCIs are designed to detect ground faults or leakage currents that can occur when electrical equipment comes into contact with water or is used in wet conditions. This device actively monitors the electrical current flowing in a circuit and can shut off the power if it senses an imbalance, which typically indicates that current is flowing through an unintended path, such as through water or a person.

GFCIs are mandated by electrical codes in areas like kitchens, bathrooms, and outdoor outlets where there is a higher risk of exposure to moisture. By using a GFCI, the risk of electric shock and potential electrical fires is significantly reduced, making them a crucial safety device in wet environments.

The other options, such as surge protectors, fuse boxes, and transformers, serve different functions and do not provide the specific protection against moisture-related electrical hazards that GFCIs are designed for. Surge protectors safeguard against voltage spikes, fuse boxes serve as a distribution point for electrical circuits, and transformers adjust voltage levels for transmission, but none address the direct concern of moisture exposure like a GFCI does.