DIY Electrical: Why and How to Install a GFCI Outlet

A How-To Electrical Work Guide

Posted by Caryn Colgan | Dec 22, 2009
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A common GFCI or ground fault circuit interrupter, looks like a typical outlet except it has a red reset button and a blue test button. According to the Consumer Product Safety Commission a GFCI "could prevent over two-thirds of the approximately 300 electrocutions still occurring each year in and around the home. Installation of GFCI devices could prevent thousands of burn and electric shock injuries each year."

A GFCI is intended to detect ground faults in order to prevent or reduce the severity of some electrical fires by interrupting the flow of electric current. A ground fault occurs when electrical current escapes from a circuit. When a human body provides a path for the escaped electrical current, electric shock occurs. This painful shock can cause burns, pain and / or death by electrocution.

Common examples of ground fault occur when someone uses a blow dryer or radio in the bathtub and the appliance tumbles into the bath water. If the appliances had been plugged into a properly functioning GFCI, the GFCI would have sensed the ground fault caused by contact with the water and switched off the outlet's power.

How a GFCI Works

A GFCI continuously monitors electricity flowing in its circuit and detects any significant loss of current. If the current flowing through the circuit changes, the GFCI quickly turns off the power to that circuit. The GFCI interrupts power almost immediately to prevent a lethal dose of electricity. A victim might feel a pain, but would not suffer permanent damage or death.

Where to Install GFCI

The National Electrical Code (the Code) requires that GFCI protection be installed for:

  • Most Outdoor Receptacles
  • Bathroom Receptacle Circuits
  • Garage Wall Outlets
  • Kitchen Receptacles
  • All Receptacles In Crawl Spaces And Unfinished Basements

Whether for the home or work place, familiarity with the three types of GFCIs could save lives:

Circuit Breaker

For homes equipped with circuit breakers, as opposed to fuses, a circuit breaker GFCI can be installed in the panel. Just as the receptacle type does, it turns off electricity or trips when a ground-fault or circuit overload occurs. Any outlet, light fixture, heater or other appliance served by the branch circuit routed through a circuit breaker GFCI will be protected. Circuit breakers should be installed in your home by a qualified electrician.


This type of GFCI is used in place of the standard receptacle found throughout most homes. It fits into the standard outlet box and protects your home's occupants from ground faults whenever an appliance is plugged into the outlet. Most receptacle-type GFCls can be installed so that they protect other electrical other outlets in the branch circuit. Receptacle-type GFCIs may be installed by do-it-yourselfers familiar with safe electrical wiring procedures.


When permanent GFCIs are not practical or affordable, portable GFCIs may be used. Plug a portable GFCI into an ordinary outlet and then plug in the appliance to be used. They are also available as extension cords. Anyone can easily use a portable GFCI.

By using or installing GFCI you protect yourself and your family from accidental shock and even electrocution. Whether you decide to do-it-yourself or install a qualified electrician, GFCI should be installed in the circuits throughout the home and garage and be tested yearly.

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