What does a Ground Fault Circuit Interrupter (GFCI) protect against?

A Ground Fault Circuit Interrupter (GFCI) is specifically designed to protect against electrical shock. It functions by constantly monitoring the flow of electricity through a circuit. If it detects an imbalance between the outgoing current and the returning current—such as when electricity is unintentionally flowing through a person to the ground—it quickly cuts off the electrical supply to prevent serious injury or even death.

This protective mechanism is crucial in environments where water is present, such as kitchens and bathrooms, where the risk of electrical shock increases significantly. By rapidly responding to ground faults, the GFCI enhances user safety, making it an essential component in modern electrical installations.

The other options refer to different electrical safety concerns but do not align with the primary function of a GFCI. Overheating of cables relates to issues of current overload rather than ground faults; voltage fluctuations pertain to irregular electrical supply and do not directly cause electric shock; while frequency discrepancies involve variations in power system frequency, rather than the dangerous current imbalances that GFCI devices are designed to detect and mitigate.