GFCI (Ground Fault Circuit Interrupter) outlets are required by code in bathrooms, kitchens, garages, and outdoor areas — anywhere water and electricity might meet. They save lives by cutting power in 1/40th of a second when they detect a ground fault. But they can fail silently, leaving you unprotected. Here's how to test yours and replace them if needed.
What Is a GFCI Outlet?
A GFCI outlet has two small buttons in the center: TEST (usually black) and RESET (usually red). It monitors the current flowing through the circuit and trips instantly if it detects even a tiny imbalance — the kind caused by current flowing through a person. One GFCI outlet can protect multiple downstream outlets on the same circuit.
- GFCI protection is required within 6 feet of any sink, in all bathrooms, garages, and outdoor outlets
- A tripped GFCI looks like a normal outlet — the only sign is the RESET button popped out
How to Test a GFCI Outlet
Testing takes 30 seconds. Plug a lamp or phone charger into the outlet and confirm it works. Press the TEST button — the outlet should immediately lose power (the lamp goes off). Press RESET — power should return. If the outlet doesn't lose power when you press TEST, or doesn't restore when you press RESET, the GFCI has failed and needs replacement.
- Test every GFCI outlet in your home twice a year — add it to your spring and fall maintenance routine
- A GFCI tester ($10 at any hardware store) is more reliable than a lamp for testing
How to Replace a GFCI Outlet
Turn off the circuit breaker for that outlet and confirm power is off with a non-contact voltage tester ($15). Remove the outlet cover plate and unscrew the outlet from the box. Note which wires connect to LINE (the power source) and LOAD (downstream outlets) terminals — take a photo before disconnecting. Connect the new GFCI: black wire to LINE HOT, white wire to LINE NEUTRAL, bare copper to ground. Screw it in, restore power, and test.
- Never skip the voltage tester — breaker labels are often wrong
- If you're only protecting one outlet, you can leave the LOAD terminals empty
- GFCI outlets cost $12–$25 — always buy a tamper-resistant model (required by code since 2008)
When to Call an Electrician
Call a licensed electrician if: the outlet sparks when you plug something in, the breaker trips repeatedly when you reset the GFCI, you find aluminum wiring (silver-colored wires), or you're uncomfortable working in the electrical box. Electrical work done incorrectly is a fire and shock hazard — there's no shame in calling a pro.
Check All Outlets on the Circuit
When a GFCI trips, it may cut power to multiple outlets downstream. If outlets in your bathroom or kitchen suddenly stop working, find the GFCI outlet (often in the bathroom or garage) and press RESET before assuming the outlet is broken.
Electrical Work Beyond DIY?
Our licensed electricians handle panel upgrades, outlet installation, and whole-home electrical inspections.