How to Install a GFCI in an Older Home

The current electrical code requires ground fault current interrupting, or GFCI, outlets in bathrooms, kitchens, laundry rooms and any other places where moisture is present. The internal breaker of a GFCI trips when it detects a current surge, thus protecting you from electrocution when your body inadvertently provides a pathway to ground. If you live in an old house with ungrounded circuitry, the code allows you to replace any outlet with a GFCI to provide grounding protection. Wiring a GFCI outlet is similar to wiring a conventional one, with one important difference: The terminal pairs aren't interchangeable.

Flat-head screwdriver
Phillips screwdriver
Voltage tester

Instructions

- 1
  Turn off the breaker that controls the circuit powering the outlet you want to replace. Test the outlet by plugging something into it, such as a lamp, to make sure it's off.
- 2
  Unscrew and remove the outlet cover plate with a flat-head screwdriver. You can discard the plate or recycle it on another outlet, because the plate for a GFCI is different and comes with the device.
- 3
  Unscrew the screws holding the old outlet to the electrical box with a Phillips screwdriver and pull the outlet from the box.
- 4
  Loosen the terminal screws on either side of the outlet and pull off the wires. Unscrew the ground screw and remove the bare ground wires if the outlet is grounded.
- 5
  Separate the wires into corresponding black/white pairs if more than one pair is connected to the outlet. Turn on the breaker, test each pair with a voltage tester and note which pair is live. Turn off the breaker after conducting this test.
- 6
  Unpack the GFCI outlet from its box and turn it over. Note the terminal labels: One pair is labeled "Line" and the other "Load." Connect the live circuit wires to the Line terminals. The black wire hooks around the brass screw and the white wire around the silver one. Tighten the terminal screws with a screwdriver.
- 7
  Connect the other wire pairs to the Load terminals in the same way. If more than one branch circuit is connected to the outlet, and therefore you have more than one wire pair, double up the black wires on the brass terminal and the white wires on the silver one.
- 8
  Twist all the bare ground wires together and connect one of them to the green ground terminal on the bottom of the outlet. If no circuit ground wires exist, omit this step, but label the cover "GFCI Protected and No Equipment Ground." This means anyone servicing the outlet has no grounding protection, and devices that rely on grounding, such as surge protectors, won't work properly.
- 9
  Push the wires into the electrical box and screw on the outlet. Attach the cover plate that comes with the outlet using the screws that come with it.

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