Do you ever test your ground fault interrupters?
I asked my wife that question and she said, in a mystified tone, that she didn't know she could.
Properly called "ground fault circuit interrupters" or GFCIs, these electrical devices are most familiar as the outlets with two rectangular buttons in the middle, often seen in bathrooms and garages.
Look closely at the face of a GFCI outlet, and you'll see the words "Test Monthly." These devices have been installed in new houses for more than 25 years, yet most homebuyers seem surprised when I mention the need to test them.
GFCIs provide protection from shock or electrocution in a way that circuit breakers and fuses do not.
Circuit breakers and fuses shut off the power if there is an overload - that is, when more electricity is being used than the wires and other components can safely conduct. They prevent overheating that could cause fires, but do not address the typical cause of electrocution.
GFCIs prevent electrocution by monitoring the electric flow in a circuit and shutting it off if leakage is detected. It takes relatively little electrical current to cause electrocution, so GFCIs are designed to detect even tiny leakages of electricity out of a circuit and shut off the power instantly, before someone can be hurt or killed.
If a GFCI is damaged, worn out or improperly installed, the electrical outlet in it may function even though the GFCI no longer provides protection from shock or electrocution. That is the reason for monthly testing.
When the "test" button on a functioning GFCI is pressed, it will trip the GFCI, shutting off the power and making the "reset" button pop out. A more thorough test is to plug a light into the outlet. The light should go out when the GFCI is tripped. Resetting the GFCI by pressing the reset button will restore power. If this test procedure does not cause the GFCI to trip, or if a light plugged into the outlet remains "on" when the GFCI is tripped, the device is not reliable and should be replaced.
Another type of GFCI is installed in the electrical service panel, in place of a conventional circuit breaker. You are likely to have one of these if your house has a whirlpool tub installed. As with the GFCI outlets, the test button on the breaker should be pressed once a month to confirm that the GFCI will trip reliably.
The National Electrical Safety Foundation has an interactive instruction on how to test GFCIs and additional information on the Internet at www.nesf.org/gfci/index.html.
Dean Uhler has been a home inspector for more than 12 years and is president of Baltimore-based Boswell Building Surveys Inc. Uhler is a member of the American Society of Home Inspectors (ASHI) and is the treasurer of the Greater Baltimore Chapter of ASHI.
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