What is the primary purpose of a ground fault circuit interrupter (GFCI)?

• A. Protects users from shock hazards in damp conditions
• B. Prevents overload of circuits
• C. Measures energy consumption
• D. Regulates voltage in the circuit

Answer: (A)

The main idea is to protect people from electric shock, especially in damp conditions, by detecting a ground fault and quickly cutting power. A GFCI watches the current flowing through the live and the return path; if any leakage occurs—such as through a person or water—the currents aren’t equal and the device trips in a split second (typically around 25 milliseconds) to stop the shock. This rapid response in wet areas is what makes a GFCI essential. It isn’t designed to prevent circuit overload (that’s the job of a regular breaker or fuse), it doesn’t measure energy consumption, and it doesn’t regulate voltage.