What is a key characteristic of a GFCI outlet?

A key characteristic of a Ground Fault Circuit Interrupter (GFCI) outlet is that it interrupts the circuit when it detects a ground fault. This is an important safety feature designed to prevent electrical shocks. A ground fault occurs when electricity finds an unintended path to the ground, which can happen if a person comes into contact with electrical current. By interrupting the circuit quickly—usually in milliseconds—a GFCI outlet minimizes the risk of severe injury or death from electric shock.

The other options do not accurately describe the primary function of a GFCI outlet. While GFCI outlets are typically placed in wet locations like bathrooms and kitchens for enhanced safety, they can also be used in dry areas, making the option that claims they only work in wet locations misleading. Additionally, controlling light fixtures is not a specific function of GFCI outlets since they do not provide dimming or switching capabilities. Finally, measuring electrical power is not a function of a GFCI outlet; it is primarily focused on protecting people from ground faults rather than monitoring energy usage.