G.F.I. stands for Ground Fault Interrupter. What is its primary function?

• A. Protects against short circuits
• B. Detects ground faults and interrupts power
• C. Stabilizes voltage
• D. Filters electrical noise

Answer: (B)

Ground Fault Interrupters are designed to protect people from electric shock by watching for current that leaks from a circuit to ground. They compare the current flowing in the live and return conductors; if any leakage to ground is detected (even a small amount), the device trips and instantly cuts power. That rapid interruption is the essential function, which is why the primary role is to detect ground faults and interrupt power.

This isn’t about preventing short circuits, stabilizing voltage, or filtering electrical noise. Short circuits involve a direct low-resistance path between hot and neutral and are handled by breakers or fuses due to the high current they can produce. Voltage stabilization and noise filtering are tasks for other devices, not GFCIs.