How to Replace a GFCI Outlet

Safety is the primary reason you are tackling this job. A GFCI (Ground Fault Circuit Interrupter) outlet is designed to monitor electrical current and trip instantly if it detects an imbalance, which is critical in moisture-prone areas like garages or kitchens. When these outlets stop resetting or trip without a clear cause, they have reached the end of their lifespan and must be replaced to keep your home protected. Performing this repair well means moving slowly and staying organized. You will need to identify which wires carry the incoming power (line) and which wires feed other outlets further down the circuit (load). Labeling your wires before you disconnect them is the difference between a ten-minute job and an afternoon of troubleshooting dead outlets in the rest of your home.

  1. Cut Power First. Go to your main electrical panel and turn off the breaker feeding the circuit for the garage outlet. Verify the power is off by plugging in a lamp or using a non-contact voltage tester to ensure the outlet is dead.
  2. Pull the Old Outlet. Unscrew the cover plate and pull the outlet from the electrical box. Use your screwdriver to loosen the mounting screws so the unit hangs freely by the connected wires.
  3. Label Line and Load. Locate the 'Line' wires (usually coming from the breaker) and the 'Load' wires (going to other outlets). Apply masking tape labels to these sets of wires before unscrewing them from the terminals.
  4. Free All Wires. Loosen the side terminal screws and remove the wires from the old GFCI outlet. Ensure the wire ends are straight and not frayed; trim them with wire strippers if they look damaged.
  5. Wire the New GFCI. Attach the Line wires to the terminals marked 'Line' on the new outlet and the Load wires to the terminals marked 'Load'. Secure the ground wire (green or bare copper) to the green screw on the mounting bracket.
  6. Verify Protection Works. Gently fold the wires back into the box and screw the outlet into place. Turn the breaker back on and press the 'Reset' button on the outlet to ensure it has power.