Wiring a Ground Fault Interrupt (GFI) Outlet
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A Ground Fault Interrupt (GFI) or Ground Fault Circuit Interrupt (GFCI) outlet is designed to provide extra protection for wet areas. If does this by measuring the flow of electricity in both the hot (black) and neutral (white) wire. If the two are not equal, then there is electricity flowing somewhere else out of the circuit and the breaker disconnects the power. Remember that small amount of alternating current (AC) can kill so make sure there is no power to the outlet box before you touch anything.
This is more common in wet area where the water comes in contact with the hot wire. Some of the current may go through the neutral wire and some may go to earth ground. Power can easily travel through water and to a ground surface like a concrete, tile, or wet carpet. The GFI reduces but does not guarantee that there is no chances of electrocution.
The average GFI outlet costs about 11 dollars. For 13 dollars you can get a GFI that includes an LED that shows you that you have power on the outlet. When the GFI faults, the light goes out. I prefer this kind of breaker myself.
Electrical wiring should only be done by a trained professional. This article is for reference to trained personnel only and does not suggest that anyone should do their own wiring.
Disconnect the power at the main breaker box before touching any outlets or wiring. Confirm that your wiring in the breaker box is to code with all black wires going to breakers and white wires going to neutral. If you see any white wires connected to a breaker, you have a big problem. There are 3 options for wiring a GFI outlet:
End of line or standalone GFI circuit
In this installation, the GFI outlet protect only itself and there are only 3 wires in the junction box: incoming hot, neutral and ground. Connect as you would a conventional outlet, There is no need to touch or use the addition connections on the outlet.
Beginning or mid-line GFI protecting only itself
In this installation, the GFI outlet protect only itself and there are 6 or more wires in the junction box. Incoming hot, neutral and ground plus outgoing hot, neutral and ground. This outlet is also wired just like a traditional outlet and does not use the extra contacts. In this configuration, you can use multiple GFI outlets, each protecting only their outlets. This configuration is good because if a breaker trips. you will still have power in the rest of circuit. It also makes it easy to find where the fault is. If you are protecting multiple outlets with one GFI, it may be difficult to find which appliance is tripping the breaker.
GFI Outlet protecting multiple outlets In this installation, the GFI outlet protect all down circuit outlets and there are 6 or more wires in the junction box. Incoming hot, neutral and ground plus outgoing hot, neutral and ground. This installation can save money since you can use conventional outlets for all down circuit location and still have the protection of a GFI. In this case, you connect the wires from the breaker box to the outlet just as a standard outlet. Then remove the tape from the extra connections and wire the down circuit hot and neutral to the LOAD - CHARGE contacts. Connect the black wire on the same side as the black wire from the breaker. Connect the white wire on the same side as the white wire from the breaker. Connect all the ground (bare wires) together and attach them to the ground contact on the GFI outlet. Wire all down circuit outlets as standard.
If you have metal junction boxes, there should be green ground wire to the metal box. This should be connected to all the other ground wires and connected to the ground contact on the bottom of the GFI outlet.
Testing a GFI Most home supply stores like Lowes and Home Depot sell a GFI tester for about 10 dollars. The tester will have lights that confirm that the outlet is wired correctly with hot on the right side facing the outlet and neutral on the left facing the installed outlet. If also has a test button that safely shorts the outlet and tests the function of the breaker. You should test and reset the GFI several time to confirm safe operation.
You can also use the test button to confirm operation of the outlet. In case you are not sure T is for test and R is for reset. A tripped outlet will have the reset button out. It will click when you press it in and reconnect the power. Here is a quick way to always remember which side is black and which is white. The wide plug is always the neutral or white wire. This is because it is more important to have the grounding leg of circuit connected than the energized leg of the circuit. If the energized leg is faulty, the appliance does not work. If the neutral is not working, the appliance can be dangerous.
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