Ground Fault (GF) Breakers
3. How ground fault breakers protect you from electric shock
Ground fault circuit interrupters (GFCIs), or GF breakers, are designed to protect you from electric shock. A ground fault occurs when electricity takes an unintended path to the ground, often through a person's body. This can happen if you touch a live wire while standing on a wet surface, or if a faulty appliance has a short circuit that energizes its metal casing.
GFCIs work by constantly monitoring the current flowing into and out of a circuit. In a normal circuit, the amount of current flowing in should be equal to the amount of current flowing out. However, if there's a ground fault, some of the current will leak out of the circuit and take a different path to the ground. The GFCI detects this imbalance and immediately trips the circuit, cutting off the power in a fraction of a second — fast enough to prevent serious injury or even death.
You'll typically find GFCI protection in areas where water is present, such as bathrooms, kitchens, laundry rooms, and outdoor outlets. This is because water is an excellent conductor of electricity, which greatly increases the risk of electric shock. The NEC mandates GFCI protection in these areas for good reason. They're a vital safety measure that can save lives.
Think of a GFCI as a super-sensitive electrical balance. It's constantly measuring the flow of electricity, and if even a tiny amount goes missing, it immediately shuts things down. This makes them incredibly effective at preventing electric shock. Like AFCIs, GFCIs also have a test button that you should use regularly to ensure they're working properly. Pressing the test button should cause the GFCI to trip, indicating that it's functioning correctly. If it doesn't trip, you should replace the GFCI immediately.