What are GFCI and AFCI?  

What’s the difference between them?

Many people know that a GFCI (often just called a “GFI”) device installed in their electrical outlets can keep them from being electrocuted in wet conditions, but most of us don’t know how it works or that there is a second similar device called an AFCI.   Here’s what they are:


A Ground Fault Circuit Interrupter (GFCI),  also known just as a Ground Fault Interrupter (GFI) or as a Residual Current Device (RCD),  is a device on your electrical outlet that turns off the power when it detects that the electricity is flowing somewhere it shouldn’t, like through metal, water, or a person.   They’re often used in bathrooms and kitchens where the chance of outlets and appliances getting wet is higher.

How GFCI Works

The device works by comparing the outgoing current (the “live”, or “hot” wire) with the returning current in the “neutral” wire.  When operating properly, these should be equal.  The GFCI switch will turn off immediately when it detects that the outgoing current is not equal to the returning current, indicating that the current is flowing somewhere that it shouldn’t.

On your outlet with a GFCI device, you will see two buttons, one test, and one reset.  Once the GFCI has shut the circuit down, you can correct the problem (remove an appliance that has fallen into the sink, for example) and then push the reset button on your electrical outlet to reset it.

The test button on the outlet is to test the GFCI to make sure it’s working correctly.  You should test it once monthly by pressing the test button and observing if the reset button pops up, indicating that the power is now off and the GFCI is working fine.  Afterward, you will need to push the reset button back in to turn the power back on.

How GFCI Devices are Installed

GFCI devices can be installed in your wall outlet or in your electrical panel, and they are even appearing now on some newer devices like hairdryers as a small box at the base of the appliance.

You can also buy GFCI devices to plug into extension cords or other devices to reduce the risk of electrocution.  This is a great idea for use in shops and outside.  Some extension cords have GFCIs built into them as well.

You can also use GFCIs to upgrade older two-prong (non-grounded) outlets to three-prong (grounded) outlets without installing any new wire. Ask your electrician about this.


Similar to a GFCI, an Arc Fault Circuit Interrupter (AFCI)  also breaks the circuit, but this device is designed to shut off the power when it detects a dangerous electric arc in the circuit.  This prevents electrical fires.

How AFCI Works

An AFCI device is designed to detect electrical current alternating at a range of particular frequenciesthat are known to be associated with wire arcing.  When it detects these frequencies for more than a couple of milliseconds, it shuts the circuit down.  Since electrical arcing is the most common cause of residential fires, this is a great preventative tool.

How AFCI is Installed

AFCI devices areinstalled in your electrical outlets in the regular rooms of your house, your bedrooms, living spaces, rec rooms, garages, etc.  They are required by modern building codes as they prevent electrical fires.  If you’re not sure, you can ask your electrician if your home has these installed, and if any need to be added to any devices in your electrical system.

Overall, GFCIs and AFCIs help prevent electrocution and electrical fires and save lives.  They are an easy and essentialway to ensure the safety of your building and its occupants.

If you would like to speak to an electrician about upgrading receptacles in your home to AFCI or GFCI receptacles, contact us  to speak to a Victoria BC Electrician about solutions for your home.