Final answer:
A ground fault interrupter (GFI) is designed to prevent electric shock by comparing the live/hot and neutral wire currents and tripping the circuit breaker when a leakage current indicates a potential hazard. It operates on the principle of electromagnetic induction, where equal and opposite emfs in a coil signal balanced currents, while an imbalance prompts a safety interruption.
Step-by-step explanation:
A ground fault interrupter (GFI) is a crucial safety device often found in locations where electrical appliances are in proximity to water, such as kitchens and bathrooms. The primary function of a GFI is to prevent electric shock by detecting any discrepancy in the current flowing through the live/hot and neutral wires. The GFI utilizes principles of electromagnetic induction to compare currents, with a built-in sensitivity to interruptions when a leakage current exceeds 5 mA, which is considered the maximum safe limit for a harmless shock.
Figure 23.35 shows how this works. When the currents are equal, they produce equal and opposite electromotive forces (emfs) in the coil wrapped around an iron ring. If the currents are not equal, indicating a leakage that could be hazardous, the GFI will trip the circuit breaker to prevent potential electric shocks. This interruption serves as a proactive measure, compelling users to address and repair the leakage cause.