How does a GFCI protect from shock hazards?

A Ground Fault Circuit Interrupter (GFCI) provides protection from shock hazards by monitoring the electrical current flowing through a circuit. If there is any imbalance in the current—indicating that some is leaking through an unintended path, potentially through a person— the GFCI quickly interrupts the flow of electricity. This rapid disconnection minimizes the duration of exposure to the electrical current, significantly lowering the risk of severe shock or electrocution.

This function is critical in areas where water is present, such as kitchens and bathrooms, because water increases the risk of shock. Other methods, such as grounding or insulation, serve different protective roles, but they do not provide the same immediate response to ground faults as a GFCI does. Grounding, for example, reduces the risk of shock by providing a path for fault current to flow safely to the ground, but it may not prevent a shock if there is a fault. Insulation can help prevent unintentional contact with live wires but does not actively monitor current flow.