NEIEP Mechanics Practice Exam

What is the function of a Ground Fault Circuit Interrupter?

1. To reduce voltage variations

2. To detect an imbalance in current between the hot and neutral wires

3. To protect devices against power surges

4. To prevent overheating in electrical circuits

The correct answer is: To detect an imbalance in current between the hot and neutral wires

The function of a Ground Fault Circuit Interrupter (GFCI) is to detect an imbalance in current between the hot and neutral wires. This critical safety device monitors the flow of electricity and can sense when a leakage current, which may occur if electrical current is flowing improperly through a person or an unintended path, occurs. When it detects even a small difference (typically around 4 to 6 milliamps) between the outgoing and incoming current, the GFCI quickly interrupts the circuit, cutting off the electrical flow within milliseconds. This helps prevent electrical shock and reduces the risk of electrocution, especially in areas where moisture is present, like bathrooms and kitchens. The other choices, while related to electrical safety and performance, do not describe the main function of a GFCI. For instance, reducing voltage variations pertains more to voltage regulators rather than GFCIs, and protecting against power surges is typically the role of surge protectors. Preventing overheating in electrical circuits usually involves circuit breakers or fuses rather than the specific detection role that GFCIs have.