Electrical Ground Fault Detection

If you have experienced an electrical shock or ground fault, it was because part of your body, perhaps your hand, had probably touched the “live” side of an electrical circuit providing a path for the electrical current to flow through your body to ground. Fortunately, there is an inexpensive device available, which if installed in household circuits, could prevent many of the electrocutions reported every year in the home. The device, known as a GFCI (Ground Fault Circuit Interrupter), was designed with the express purpose of protecting people from fatal or severe electrical shocks. Many fires may be prevented and the severity of others reduced by the rapid detection of a ground fault by the GFCI causing it to interrupt the circuit.

Step 1 – Installation Considerations

Three types of GFCI’s are commonly available. The first is a device that simply plugs into the common household outlet box and will give protection against a ground fault detected whilst using any electrical product. The second type may be installed as a circuit breaker in any panel box for selected circuits. It will also trip for an overload or short circuit situation. The third type is a portable device which may be used where it is not practical to install a permanent device. This type of device may be supplied as an extension cord terminating with the GFCI.

Step 2 – Installing a GFCI

Knowledgeable consumers who are familiar with wiring regulations may install the outlet socket GFCI by following the instructions supplied with the device. The panel box type of device, on the other hand, is best installed by a qualified electrician. If there are any doubts about the installation procedure, leave the installation to a qualified professional. No specialized equipment or knowledge is required to install the portable type of GFCI.

Step 3 – Testing the Devices

It is advisable to test the GFCI at least once a month to ensure correct operation and to check that you are being protected from a possibly fatal accident. In any case, the GFCI should be tested immediately after installation to verify correct operation and circuit protection. The outlet socket GFCI is tested by plugging a table lamp into the device and making sure that it is “On”. Press the “Test” button. If the device is working correctly, its “Reset” button will pop out and the table lamp will go out. If the light does not go out but the “Reset” button pops out, the possibility exists that the device has not been wired properly. A qualified electrician should be called to rectify any wiring errors. The GFCI should be replaced if the “Reset” button will not pop out as the device has become defective. If the lamp goes out and the GFCI is working properly, pressing the “Reset” button will restore the outlet’s power. 

It has become a requirement since 1973 that GFCI protection be used for most outdoor receptacles. Since 1975 they have also been required on bathroom sockets, from 1978 on garage walls, from 1987 on kitchen sockets and from 1990 in basements and crawl spaces.