Elevator Mechanic Practice Exam 2025 - Free Elevator Mechanic Practice Questions and Study Guide

A Ground Fault Interrupter (GFI), or Ground Fault Circuit Interrupter (GFCI), operates by sensing an imbalance in the current between the ground and neutral wires. Essentially, it monitors the electrical current flowing through these wires; if it detects that the current flowing back through the neutral wire is significantly different from the current flowing through the ground wire, this indicates a leakage or a fault, which could potentially cause electric shock or fire hazards.

When the GFI detects this discrepancy—often as low as a few milliamps—it acts quickly to cut off the electrical supply to prevent harm. This mechanism is crucial in environments where the risk of electrical shock is increased, such as bathrooms and kitchens, making it an essential safety feature in modern electrical systems.

The focus on the ground and neutral wires is key because they are part of the system that connects back to the power source and provides safety and compliance with electrical codes. The other options involve imbalances and monitoring between different wire combinations that do not accurately represent how GFI technology is designed to function.