GFCI stands for Ground Fault Circuit Interrupter. It's one of the most important safety innovations in residential electrical systems — and one of the most frequently misunderstood. Here's what every homeowner in Ontario needs to know.
How does a GFCI outlet work?
A standard outlet doesn't monitor the electricity flowing through it. A GFCI outlet does — it measures the current on both the hot and neutral conductors. Under normal conditions, these are equal. If there's a ground fault (electricity taking an unintended path — like through your body), the current difference triggers the GFCI to cut power in 1/40th of a second.
This is fast enough to prevent electrocution in most circumstances. A regular circuit breaker isn't — breakers protect against overloads and short circuits, not ground faults.
The test and reset buttons on a GFCI outlet should be checked monthly. Press TEST — the outlet should go dead. Press RESET — power should return. If either fails, replace the outlet immediately.
Where are GFCI outlets required by Ontario code?
- Bathrooms — all receptacles within 1.5 metres of a water source
- Kitchens — all countertop receptacles within 1.5 metres of a sink
- Garages — all receptacles, including those dedicated to appliances
- Outdoor outlets — all exterior receptacles
- Unfinished basements and crawl spaces
- Boat docks and swimming pools
- Any area near a laundry tub or utility sink
GFCI outlet vs. GFCI breaker
There are two ways to provide GFCI protection: install a GFCI outlet (which also protects downstream outlets on the same circuit) or install a GFCI breaker in your panel. GFCI breakers protect every outlet on that circuit but cost more. GFCI outlets are more common in residential applications because they're cost-effective and easy to identify when they trip.
When selling a home in Ontario, electrical safety inspections often flag missing GFCI protection. Addressing it before listing avoids negotiation headaches and demonstrates care for the property.
Safer Electric Team
Licensed Electricians · Toronto, ON
Our team of licensed GTA electricians writes these guides to help homeowners make informed decisions. Every article is reviewed for technical accuracy.