An inexpensive electrical device, if installed in household branch circuits, could prevent over two-thirds of the approximately 310 electrocutions still occurring each year in and around the home. In addition, injuries to many thousands of consumers from electric shock and burns could also be prevented by installation of this device. The device is a ground-fault circuit-interrupter (GFCI). The GFCI is designed to protect people from severe or fatal electric shocks. Because a GFCI detects ground faults, it can also prevent some electrical fires and reduce the severity of others by interrupting the flow of electric current.

The Problem:

Have you ever experienced an electrical shock? If you did, the shock probably happened because your hand or some other part of your body contacted a source of electrical current and your body provided a path for the electrical current to go to ground, so that you received a shock.

An unintentional electric path between a source of current and a grounded surface is referred to as a "ground-fault". Ground faults occur when current is "leaking" somewhere; in effect, electricity is escaping to the ground. How it leaks is very important. If your body provides a path to ground for this leakage, you could be injured, burned, severely shocked, or electrocuted.

Some examples of consumer accidents underscore this hazard:

Two children, ages five and six, were electrocuted in Texas when a plugged-in hair dryer fell into the tub in which they were bathing.

A three-year-old Kansas girl was electrocuted when she touched a faulty countertop appliance and a water spigot.

A 52-year-old man was planning to work in the crawl space under his house. He had the 3-prong cord plug from the lamp plugged into an extension cord which was plugged into a GFCI-protected outdoor receptacle on the porch. The ground was wet under the house. When he touched the metal case of the lamp in search of the on/off switch, he received an electrical shock but was not electrocuted because the GFCI switched the power off in a matter of milliseconds. The lamp was later tested and showed it was leaking an extreme amount of current.

The two electrocutions occurred because the electrical current escaping from the appliance traveled through the victim to ground (in these cases, the grounded plumbing fixtures). Had a GFCI been installed, these deaths would have been prevented because a GFCI would have switched off the power before the electrocution occurred.

How the GFCI Works:

In the home wiring system, the GFCI constantly monitors electricity flowing in a circuit to sense any loss of current. If the current flowing through the circuit differs by a small amount from that returning, the GFCI quickly switches off power to that circuit. The GFCI interrupts power faster than a wink of an eye to prevent a lethal dose of electricity.

You may receive a painful shock, but you should not be electrocuted or receive a serious shock injury.

Here is how the GFCI could work in your house:

Suppose a bare wire inside an appliance touches the metal case. The case is then charged with electricity. If you touch the appliance with one hand while the other hand is touching a grounded metal object, like a water faucet, you will receive a shock..

If the appliance is plugged into an outlet protected by a GFCI, the power will be shut off before a fatal shock would occur.

Availability of GFCI's:

Three common types of ground-fault circuit-interrupters are available for home use: wall-receptacle, circuit breaker and portable plug-in type.

Receptacle Type. This type of GFCI is used in place of standard duplex receptacle found throughout the house. It fits into the standard outlet box and protects you against ground faults whenever an electrical product is plugged into the outlet. Most receptacle-type GFCI's can be installed so that they also protect other electrical outlets further down stream in the branch circuit.

Circuit Breaker Type. In homes equipped with circuit breakers rather than fuses, a circuit breaker GFCI may be installed in a panel box to give protection to selected circuits. The circuit breaker GFCI serves a dual purpose--not only will it shut off electricity in the event of a ground-fault, but it will also trip when a short circuit or an overload occurs. Protection covers the wiring and each outlet, lighting fixture, heater, etc., served by the branch circuit protected by the GFCI in the panel box.

Portable Type. Where permanent GFCI's are not practical, portable GFCI's may be used. One type contains the GFCI circuitry in a plastic enclosure with plug blades in the back and receptacle slots in the front. It can be plugged into a receptacle; then, the electrical product is plugged into the GFCI. Another type of portable GFCI is an extension cord combined with a GFCI. It adds flexibility in using receptacles that are not protected by GFCI's.

Where GFCI's Should Be Considered:

In homes built to comply with the National Electrical Code (the Code), GFCI protection is required for outdoor receptacles, bathroom receptacles, garage wall outlets, some kitchen receptacles, crawl spaces and unfinished basements.

Owners of homes that do not have GFCI's installed in all those critical areas specified in the latest version of the Code should consider having them installed. For broad protection, GFCI circuit breakers may be added in many panels of older homes to replace ordinary circuit breakers. For homes protected by fuses, you are limited to receptacle or portable-type GFCI's, and these may be installed in areas of greatest exposure, such as the bathroom, kitchen, basement, garage, and outdoor circuits.

A GFCI should be used whenever operating electrically-powered garden equipment (mower, hedge trimmer, edger, etc.). Consumers can obtain similar protection by using GFCI's with electric tools (drills, saws, sanders, etc.) for do-it-yourself work in and around the house.

Installing GFCI's:

Circuit breaker and receptacle-type GFCI's may be installed in your home by a qualified electrician. Do not attempt to install them yourself.

The portable GFCI requires no special knowledge or equipment to install.

Test the GFCI once a month to make certain it is working at all times. To check the unit, press the test button. There will be an indicator to show if it is working properly or not. If it is working, it will disconnect the power from the protected circuit or outlet. If not, have the device replaced. Press the reset button to restore power.