GFCIs Explained By The Pros. Today, we’re diving into Ground Fault Circuit Interrupters—commonly known as GFCIs or GFIs. This is part one of a multi-part series exploring how these devices work and where they’re used. Stick around—you might just learn something new!
What Is a GFCI?
GFCIs (Ground Fault Circuit Interrupters) are safety devices designed to detect electrical leakage to ground—that is, any difference in current between the hot and neutral wires. If that difference exceeds 5 milliamps, the GFCI immediately trips to prevent potential shocks.
They are essential in areas where moisture is present, like bathrooms, kitchens, garages, and outdoor outlets. These outlets help protect people from electrical hazards and are a requirement under electrical codes near water sources.
Common Types of GFCIs
There are different kinds of GFCIs on the market. Some are high quality; others… not so much. From years of experience, we’ve learned that Leviton GFCIs are among the most reliable. They come in several varieties:
- 15A and 20A models for indoor use
- Weather Rated (WR) versions for outdoor applications
To identify a weather-rated GFCI, look for the “WR” label on the device.
Important GFCI Facts You Might Not Know
1. Initial Setup Requires a Reset
When a GFCI is first installed, it must be reset before it will work. This initial reset activates the internal electronics. After that, the outlet will function as normal.
2. Line vs. Load
On the back of a GFCI, you’ll see terminals labeled Line and Load:
- The line is where your incoming power connects.
- The load is used to protect additional downstream outlets.
It’s critical that these are not mixed up. Connecting incorrectly can lead to a GFCI that appears to work (lights up), but delivers no power to the outlet or anything downstream.
3. Protecting Multiple Outlets
A single GFCI can be used to protect multiple other outlets. For example, you might have one weather-rated GFCI protecting four outdoor plugs via the load terminals. However, be careful: don’t install multiple GFCIs on the same circuit. If the first trips, all others downstream will need to be reset too—causing confusion and unnecessary service calls.
Visual Indicators and Reset Behavior
Some GFCIs have indicator lights:
- A green or white light shows the outlet is functioning properly.
- A red light may flash when the outlet needs to be replaced.
Reset and test buttons are standard. Most manufacturers recommend testing the outlet at least every six months using the built-in test button.
Installation Notes
- 15A GFCIs are designed for 14-gauge wire
- 20A GFCIs are for 12-gauge wire
A strip of yellow or orange tape often covers the load terminals during installation. Leave that in place unless you’re wiring a downstream load.
Use an in-use waterproof cover outdoors to protect plugged-in devices from rain and reduce nuisance tripping caused by moisture.
Tamper-Resistant & Faceless Options
GFCIs are available in:
- Tamper-resistant (TR) and non-tamper-resistant versions
- Standard receptacles with test/reset buttons and plug slots
- Faceless GFCIs, which include test/reset buttons but no outlet holes—ideal for locations like jacuzzi tubs, where you don’t need an accessible plug
GFCI Circuit Breakers
A step up in protection is the GFCI circuit breaker, which installs directly into your electrical panel. These breakers protect the entire circuit and include built-in test/reset functionality. Though they cost more upfront (around $80), they often reduce the need for multiple outlet installations and simplify troubleshooting.
What If There’s No Reset Button?
Sometimes you’ll come across an outlet that says “GFCI Protected” but has no reset button. That means the outlet is downstream of another GFCI. If it loses power, you’ll need to find the upstream GFCI to reset it.
Safety Reminders
- Always shut off power before working on electrical systems.
- Make sure you understand line and load wiring before installation.
- Consult a licensed electrician before attempting any electrical work.
- GFCIs are required within 1.5 meters (5 feet) of water sources like sinks, pools, or hot tubs.
Final Thoughts
That’s it for today’s overview on GFCIs! These safety devices may seem simple, but they play a crucial role in preventing serious accidents. Be sure to like and subscribe to stay up to date with future videos in this GFCI series.
