GFCI receptacles, also called GFI’s, or known by their proper name ground fault circuit interrupters are life saving devices first used in the 1970’s. You will see them around your home in kitchens, bathrooms, basements, garages and outside. What distinguishes them from regular receptacles is the test and reset button on the face of them.
It’s important to TEST them on a monthly basis. As an electrician we are used to telling people this. But does anyone actually test them? Probably not!
So what exactly does a GFCI do, and why should I be testing them?
A GFCI senses current (amps) leakage to ground. If any more than 5 milliamps of leakage is detected, the device trips. The best way to explain this is to imagine you have 1 hot wire and 1 neutral wire. The hot wire is the current (amps) flowing OUT and the neutral is the current (amps) flowing BACK. If 10 amps is flowing OUT on the hot, the GFCI is measuring this and expecting 10 amps to be flowing BACK on the neutral. A discrepancy of 5 milliamps or more and the GFCI trips cutting off power!
For those who don’t know what a milliamp is, and believe me I can completely understand why that would be, it is a TINY bit of amperage.
Everyone has seen a nightlight like the one pictured correct? Well to give some context to just how small 5 milliamps is, a nightlight like this draws around 58 milliamps. So yeah, 5 milliamps is pretty small! The idea here is that the 5 milliamps is such a low amount of current that the GFCI will trip before someone can be hurt.
The big question is, if the GFCI does trip where did that difference in current go? To ground / a person! Imagine using an appliance near a sink full of water without a properly working GFCI, scary stuff!
Some receptacles in my kitchen are not GFCI’s, but carry their protection. How does this work?
Take a look in your kitchen. You may have 2 GFCI receptacles on your kitchen counter with a bunch of other receptacles that are not GFCI’s. This works because a single GFCI can “load protect” any number of downstream receptacles. The GFCI itself has a second set of terminals to connect the downstream wiring to. This is great because it saves some cost, as a GFCI is not needed at every receptacle location.
The following diagram shows this in action.
The GFCI function can also be incorporated into the circuit breaker. This is becoming more common in newer installations. If your kitchen was remodeled in 2014 or later, there is an excellent chance you won’t have any GFCI receptacles in your kitchen. You will have a circuit breaker that has the GFCI function. Hopefully your electrician told you about this, as it still needs to be tested on a monthly basis.
Take a look around your home and identify the GFCI receptacles you do have.
You will see the TEST button on the face of it. Using your finger tip press the button and it should “trip” and make a click sound. If it trips you know it is working. The next step is to depress the reset button all the way until you hear and feel another click. At this point it’s reset and should be working again. It is really that simple! If it won’t reset, the GFCI may be defective and need to be replaced.
Newer model GFCI receptacles will have indicator lights on them. One common brand has a green light when it’s working and a red light when it’s tripped. Modern GFCI’s used outdoors are “weather resistant” (WR) and use some different metals which help it hold up to the rigors of being exposed to the elements.
If you have any GFCI circuit breakers in your electrical panel simply depress the test button on them. The circuit breaker will trip to its middle position. Now turn the circuit breaker OFF, and then back ON. If it moves back to the ON position it has reset properly. If it will not move to the ON position and continues to trip, an electrician will be needed to troubleshoot a potential issue.
Please TEST your GFCI’s this month, it could save someone’s life!