Kevin O’Connor and master electrician Heath Eastman meet back at the shop to talk about GFCI outlets. After discussing what a GFCI is and what it does, Heath shows Kevin how it works, the different types of installations that may exist, and how to test a GFCI’s function.
What are GFCIs?
GCFIs exist to protect the user. These devices detect when current from the hot conductor contacts a non-current-carrying metal part and cut off power to the circuit.
This means that GFCIs detect when current escapes the circuit due to a short circuit, such as the wire touching a metal box, a plumbing pipe, or the user standing in a puddle of water when plugging something in. Rather than continuing to feed current into that object or person, the GFCI trips and prevent further flow of electricity.
Where They’re Required
GFCIs are not new. They’ve been around since the 1960s, and as such, code requires them in certain places. Typically required spaces include kitchens, bathrooms, and outdoor outlets. Anywhere water is usually present from a sink, shower, or toilet, or environmental causes like rain, snow, and dew, are locations where GFCIs are typically required.
How Do GFCIs Work?
GFCIs operate by sensing the amount of current is being used by a device. The device looks for the same amount of current coming into the device and back out of the device. If the amount of current drops on the return side of the device, the GCFI will sense an imbalance (typically caused by a short of some sort) and trip the outlet off.
Types of GFCI Devices
There are typically two types of GFCI devices: outlets and breakers. GFCI outlets generally have a test and reset switch on their fronts, which is the tell-tale sign that a GFCI protects the circuit.
Should the device trip, the reset button will jump outward, and the user must then reset it to reactivate the circuit beyond the outlet. Breakers work similarly, though they install inside the main electrical panel and protect the entire circuit.
GFCI Circuits
Just because an outlet doesn’t have a test and reset button on its front doesn’t mean it’s not GFCI-protected. These devices are designed to shut off the entire circuit past the GFCI outlet, so if an outlet is on a GFCI-protected circuit, a short will cause the GFCI to trip regardless of where the short occurs.
So, if a GFCI is installed first in a series of 5 outlets, a short at the 5th outlet will cause the GFCI to trip, protecting the entire circuit.