Electrician's Licensing Practice Exam

What is the purpose of a GFCI?

1. To regulate voltage

2. To protect against ground faults

3. To serve as a circuit breaker

4. To measure current

The correct answer is: To protect against ground faults

A Ground Fault Circuit Interrupter (GFCI) is specifically designed to protect against ground faults, which occur when there is an unintended path between the source of current and the grounded surface. In more practical terms, it monitors the electrical current flowing through a circuit and can detect imbalances between the outgoing and incoming current. If it senses that the current is flowing through an unintended pathway (like through a person who is grounded), it will shut off the power to prevent electric shock. This function is critical in areas where the risk of electrical shock is higher, such as bathrooms, kitchens, and outdoor locations. GFCIs enhance safety by providing a quick disconnection of power, which can save lives. The other options serve different purposes: regulating voltage is more associated with transformers or voltage regulators, while circuit breakers serve to interrupt excessive current flow to prevent circuit overloads and short circuits, and measuring current pertains to devices like ammeters. Thus, the primary purpose of a GFCI is to protect against ground faults, making it indispensable for safe electrical installations in areas prone to moisture.