J. Fritscher – April 17, 2024
By now, most of us have heard of GFCI receptacles and are even familiar with how to reset them if they have tripped, but if you’d like to learn more about what a GFCI is, and more importantly, how it protects us, we invite you to keep reading.
GFCI is an abbreviation for Ground Fault Circuit Interrupter. Great…what does that mean? A ground fault occurs when electrical current deviates away from the return path to any grounded surface (this includes water). A GFCI senses this deviation and interrupts the circuit, which helps to prevent electrical shock or electrocution.
Electrical current can be thought of as the flow water, and electrical wires as pipes that the water flows through. If we think of the electrical wires as a closed loop system, then we have a source (or tank) of electricity that has loops of wire (pipes), that the current (water) flows into and then returns back to the source (tank). If a leak were to occur anywhere along a pipe, the tank would not have all of the water it supplied returned to it. The leak would be akin to a ground fault because the water is deviating from its intended path back to the tank.
In the case of water, we would want to shut off the supply to the pipe with the leak to avoid a bigger mess and wasting water, but in the case of electricity it is to save lives.
Electrical current can actually flow through the human body to a grounded surface, and this is what causes electrical shock, and sometimes electrocution. It takes a very small amount of electrical current to stop the heart, so it’s important to stop the unintentional flow of current as soon as possible just in case that current is passing through someone’s heart.
A GFCI does just that. GFCI devices are designed to monitor the current flowing into and out of the circuit. If the current measurement differs by 6mA (0.006 amperes), the device will “open” the electrical circuit to stop the flow of current.
Ever wonder why GFCI receptacles are always near kitchen sinks or in bathrooms? This is because water can conduct electricity or act as a grounded surface. It also makes electrical current flow through our bodies easier if we happen to get our skin wet.
GFCI protection has been required outdoors and in bathrooms since the mid-seventies, and in kitchens since the late eighties. Additional required locations have been added over the years in areas where water is present such as wet bars and laundry/utility rooms.
GFCI protection can be built into corded devices or extension cords, receptacles, or circuit breakers. A GFCI built into a cord only protects against a ground fault that occurs in the device or a device plugged into the cord. A GFCI receptacle protects against faults at the receptacle but can also service downstream receptacles as well. A GFCI circuit breaker will protect against faults that occur anywhere along the entire circuit.
If you’re working with electricity around water, especially while using handheld electric devices or power tools, using GFCI protection can help prevent serious injury or death in the event of a fault.
Now that we know what a GFCI is, next time we’ll look closer at how they work and common reasons they may be tripping too frequently, or not tripping at all.