by Craig Dunman, Master Electrician
Most people don’t think twice about their electrical system until something stops working—or worse, someone gets shocked or a fire starts. As a master electrician with decades of experience in the field, I can tell you this: the small safety devices in your home matter. And if you don’t understand how GFCIs and AFCIs work—or why they’re different, you’re not alone. Most homeowners don’t. That’s why I’m laying it out plainly. Here’s what you need to know to keep your home and, most importantly, your family safe.
What Is a GFCI?
GFCI stands for Ground Fault Circuit Interrupter. It’s a safety device designed to protect people from electric shock due to unintended current paths—specifically when electricity flows somewhere it shouldn’t, like through a conductive surface or a person.
Here’s what that means in practice:
The GFCI constantly monitors the flow of electrical current. Under normal conditions, the current flowing out through the hot (live) wire and back through the neutral wire should be equal. If there’s even a small difference—say, 5 milliamps—the GFCI cuts power in a fraction of a second. This prevents harm by stopping electricity from traveling through an unintended path, like through a wet countertop, a tool casing, or a person touching a grounded surface.
Where You’ll Find Them:
- Bathroom outlets
- Kitchen counters (within 6 feet of the sink)
- Garages
- Outdoor outlets
- Laundry rooms
Modern code requires these in all wet or damp locations because moisture increases the risk of ground faults.
What Is an AFCI?
AFCI stands for Arc Fault Circuit Interrupter. This device is designed to prevent electrical fires caused by arcing—tiny, high-temperature sparks that can occur when wires are damaged, pinched, deteriorated, or loosely connected.
Arcs can form between two points of wiring that are not supposed to be touching, and they can happen behind walls, in cords, or anywhere connections are degraded. These arcs often generate intense heat without drawing enough current to trip a standard breaker. That’s why AFCIs were created.
The AFCI monitors the waveform of the current and detects irregularities characteristic of arc faults. When it senses this pattern, it cuts the power to stop the arc before it ignites surrounding materials like insulation or wood framing.
Where You’ll Find Them:
- Bedrooms
- Living rooms
- Hallways
- Any general lighting or outlet circuit in newer homes
Some homes now use combination devices that offer both GFCI and AFCI protection—particularly in areas like laundry rooms, basements, and kitchens where both moisture and arcing risks exist.
The Difference Between GFCI and AFCI
| Function | GFCI | AFCI |
|---|---|---|
| Main Purpose | Protects people from shock | Prevents electrical fires |
| Detects | Ground faults (current leaking to ground) | Arc faults (damaged or sparking wires) |
| Typical Location | Near water (bathrooms, kitchens, outdoors) | In the breaker panel protecting bedroom/living area circuits |
| Visual Clue | Test and Reset buttons on outlet | Test button on breaker (in panel only) |
To keep it simple: GFCI protects people. AFCI protects buildings. You need both.
How to Test a GFCI (And What the Results Mean)
You should test every GFCI outlet in your home once a month. It takes less than 30 seconds, and it could save your life.
Here’s how:
- Plug in a lamp or nightlight.
- Turn it on so the light is visible.
- Press the TEST button on the GFCI outlet.
- The light should turn off.
- That means the GFCI tripped correctly.
- Press the RESET button.
- The light should come back on.
If it doesn’t work:
- If the light stays on after pressing TEST, the GFCI isn’t working and needs replacement.
- If the RESET button won’t stay in, your outlet may not have power or there may be a wiring issue.
GFCIs can wear out over time. Just because the outlet still gives power doesn’t mean the safety function is still active. Test it to be sure.
How to Test an AFCI Breaker
This one requires a trip to your electrical panel. Here’s how to check it:
- Locate your breaker panel.
- Find any breaker labeled AFCI or Combination AFCI.
- Press the small TEST button on the breaker.
- The breaker should immediately trip.
- Flip it fully to OFF, then back to ON to reset it.
If it doesn’t trip:
- The AFCI breaker may be defective and needs replacing.
- A breaker that won’t reset may be responding to a real fault in the circuit—it’s doing its job.
Some AFCI breakers run their own internal self-tests regularly. You might see the breaker flash or blink—this is normal. But if the breaker trips on its own during one of those checks, that means it detected a problem. Don’t just reset it. If an AFCI trips, especially more than once, it’s not a fluke—it’s catching something. You need a licensed electrician to evaluate the circuit.
Never ignore a breaker that won’t stay on. It’s trying to tell you something.
Common Misconceptions (That Can Get You Hurt)
- “The outlet still works, so it’s fine.” Wrong. The safety mechanism can fail silently.
- “I pressed the test button once years ago.” Not good enough. Test monthly.
- “I have AFCIs, so I don’t need GFCIs.” Wrong again. They serve different functions.
When to Call an Electrician
You don’t need us for every little thing, but here’s when you should pick up the phone:
- GFCIs or AFCIs that won’t reset
- Outlets that feel warm to the touch
- Frequent tripping of the same breaker
- You’re not sure which outlets are protected (or none are labeled)
- You’re remodeling or adding new appliances
A licensed electrician can run a quick test on your system and verify your protection. It’s fast, it’s not expensive, and it’s one of the best ways to reduce your risk of shock or fire.
GFCIs and AFCIs aren’t optional—they’re code for a reason. These devices have saved thousands of lives and prevented countless fires. But only if they’re working.
If you’re not sure about your protection, we’re here to help. Give us a call or click here for our contact form, and we can come out and do an electrical inspection for you!
(512)280-8847 . becky@dunmanelectric.com . contact us
For more articles like this, check out our toolbox.
