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pdfPrintable PDF What is a GFCI and AFCI

A Ground Fault Circuit Interrupter (GFCI) is a safety device that senses a shock hazard and interrupts the flow of electricity in the circuit.

What is a GFCI?

The following information is deemed reliable but should not be your sole source for decisions you make.

A Ground Fault Circuit Interrupter (GFCI) is a safety device that senses a shock hazard and interrupts the flow of electricity in the circuit. The GFCI is designed to trip and interrupt the circuit at approximately 5 to 8 milliamps (MA). The standard fuses and breakers are not as sensitive and therefore slower in reacting. The purpose is to protect against electrocution in areas where a person is susceptible to grounding hazards, such as wet locations and when using equipment outside.

There are three types of GFCI’s that can be used in residential properties.

The circuit breaker type is installed in the electric panel and protects selected circuits. Although there are limits to the number of outlets protected sometimes a single wire will run from the breaker, through the house, to bathrooms, kitchens and outside locations protecting each of theses sites.

The receptacle type is used in place of the standard duplex receptacles found throughout the house. Some GFCI’s may protect other outlets down line in the same circuit. Off times the protected outlets will be in different rooms. For example if an outlet in a patio does not work you should check other locations such as baths or the garage for a tripped GFCI which protects the entire circuit.

The portable plugin type may be used in areas where permanent protection is not available such as extension cords for power tools operated outside from an unprotected circuit.

It is important to protect exterior outlets with proper covers. Theses locations can be susceptible to moisture and can trip outlets at locations becoming a nuisance.

Why don’t they work?

At a Florida Association of Building Inspectors meeting a manufactures representative said an unofficial survey by Home Inspectors reveled that 25% to 35% of GFCI type outlets were not functioning properly. They are sensitive electronic equipment typically found in wet locations and need to be properly connected to the electric wirings. Some outlets provided power but not the desired protection creating a hidden hazard.

Some years ago the manufacturer, Leviton, redesigned GFCI’s so that if they are not providing proper protection they would not supply power. Unfortunately they still have the tendency to fail sooner than standard outlets. The cost of GFCI units has dropped over the years from approximately $40.00 to $15.00 retail. This is why in newer houses most outlets are individual protected rather than run from a breaker in the panel box or other outlet as described above.

What is an AFCI?

The function of the GFCI is to protect people from the deadly effects of electric shock. The function of the AFCI is to protect the branch circuit wiring from dangerous arcing faults that could initiate an electrical fire. An electric "arch" occurs when electricity jumps through the air from one point to the other. They commonly occur and are not a concern in electric motors and when light switch are turned on and off. They can also occur when wires become frayed or damaged and this can cause fires in residential dwellings. Conventional over current devices do not detect low level arcing that has the potential to initiate electrical fires. An AFCI is a product that is designed to detect a wide range of arcing electrical faults and thus help reduce the electrical system from being an ignition source of a fire. An AFCI provides a higher level of protection than a standard circuit breaker by detecting and removing the hazardous arcing condition before it becomes a fire hazard. The 2005 NEC® states that AFCIs must be placed on bedroom power and lighting circuits.

Where do I need a GFCI?

In 1971 GFCI’s were first required in exterior locations and over the years the required locations have changed almost yearly. On porches the requirement was created in 1973 deleted for some locations in 1978 and changed back to all locations in 1996. Presently they are required in all wet locations.

When remolding outlets must comply to current code and it is suggested that all areas of potential hazard be upgraded.

The chart below was produced by Jerry Peck & Norm Sage whom both of whom hold multiple qualifying licenses and held many elected positions in the Florida Association of Building Inspectors. Consider using their services for you inspection needs in the South Palm Beach to Miami area.



gfci chart

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