Q: I was hoping you guys could tell your readers what the benefits would be in installing GFCI electrical outlets even if there is no grounding wire. There are probably many homeowners who would be willing to install GFCIs themselves but who aren’t able to install a grounding wire or are unwilling to pay an electrician to install one. I purchased a package of three that came with little stickers to put on the outlet if it is not grounded.
Maybe you could suggest the best locations to install them (bathroom, by kitchen sink, by laundry tub)?
A: Great suggestion. The benefit is summed up in one word: safety.
Ground-fault circuit interrupters (GFCIs) are essential to a safe residential electrical system, especially an older one. At one time or another every owner of an older home has pondered why their receptacles have two prongs when most appliances are equipped with three-pronged plugs. Back in our "rookie" days we used our fair share of plug adapters to make the SkilSaw run from a two-pronged outlet. Luckily, we didn’t get fried.
Look at a modern 120-volt outlet. There are two vertical slots and a round hole centered below them. The left slot is slightly larger than the right. The left slot is the "neutral"; the right slot is the "hot"; and the hole below them is the "ground."
Behind the scenes, a black wire is connected to the hot hole, and a white wire is connected to the neutral hole. A noninsulated wire is connected to a green screw that is connected to the ground. The ground slot and the neutral slot of an outlet are identical. In the circuit panel you’ll find that the neutral and ground wires from all of the outlets go to the same place: the ground.
Electricity flows from the hot side of the distribution panel through the "hot" wire through plugs and switches to the neutral wire and back to the neutral side of the panel.
Plug in an appliance and power is diverted from the plug to the device, allowing electricity to flow through the device to run a motor, heat some coils or light a lamp.
Circuit breakers in the distribution panel protect the electrical system from overload and possible fire. If a circuit breaker detects a short in the system — for example, when a hot wire touches a neutral wire — it cuts off the flow of electricity. The circuit breaker prevents the wires in the wall or the outlet itself from overheating and starting a fire.
Think of a GFCI as a mini-circuit breaker. It protects against electrical shock. An unintentional electric path between a source of current and a grounded surface is a "ground fault." Hence the name ground-fault circuit interrupter. Ground faults occur when current is leaking. In effect, it’s electricity escaping to the ground. If your body provides the path to the ground, you could be burned, severely shocked or killed. …CONTINUED
Two examples of accidents underscore that hazard. According to the Consumer Product Safety Commission:
- Two children, ages 5 and 6, were electrocuted in Texas when a plugged-in hair dryer fell into the tub in which they were bathing.
- A 3-year-old Kansas girl was electrocuted when she touched a faulty countertop.
GFCIs are a good idea on an older, ungrounded system because a GFCI receptacle is not dependent on an independent ground wire to function because it does not measure shorts to ground. Rather, a GFCI monitors the amount of current flowing from the hot leg to the neutral leg of the receptacle. If there is any imbalance, the circuit is tripped.
A GFCI is able to sense a mismatch as small as 4 or 5 milliamps, and it can react as quickly as one-thirtieth of a second, shutting the circuit off. So a ground-fault circuit interrupter is a critical layer of protection in areas where it’s likely that electricity can come into contact with water or other ungrounded conductors.
GFCIs are easy to install for someone with a basic knowledge of electrical wiring. They install much like a regular receptacle with the hot wire (black) attached to the brass screw on the receptacle and the neutral wire (white) attached to the silver screw.
Make sure to turn off the power to the receptacle before taking the plate off. GFCI protection is required for most outdoor receptacles, bathroom receptacle circuits, garage wall outlets, kitchen receptacles and all receptacles in crawl spaces and unfinished basements. This can be accomplished by installing a GFCI circuit breaker on these circuits or installing a GFCI receptacle at the first outlet downstream from the distribution panel. This will protect all receptacles downstream.
Finally, GFCI receptacles should be tested monthly. Plug a nightlight or lamp into the outlet. The light should be on. Then, press the "test" button on the GFCI. The GFCI’s "reset" button should pop out, and the light should go out. If the reset button pops out but the light does not go out, the GFCI has been improperly wired. If the reset button does not pop out, the GFCI is defective and should be replaced. If the GFCI is functioning properly, and the lamp goes out, press the reset button to restore power to the outlet.
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