Construction Wiring 2 Practice Test 2025 - Free Practice Questions and Study Guide

A Ground Fault Circuit Interrupter (GFCI) is designed to enhance safety by protecting individuals from electric shock. It operates by monitoring the electric current flowing through a circuit and detects any imbalance between the current going to and returning from a device.

The correct choice indicates that the GFCI activates when it detects a current imbalance between 4 mA and 6 mA. This range is significant because modern GFCIs are designed to trip when they detect a leakage current as low as 4 mA, which can be sufficient to cause a harmful electric shock. The threshold is deliberately set low to provide effective protection for personal safety. When the imbalance reaches this level, the GFCI interrupts the circuit to prevent potential electrical hazards.

This safety feature is crucial in preventing severe injuries in wet or outdoor conditions where the risk of electric shock is higher. The function of GFCIs is especially vital in areas like bathrooms and kitchens, reinforcing the importance of selecting the correct threshold for detection, which in this case is 4 to 6 mA.