Electrical Ground Fault Protection

Building Code Books and GFCI Receptacles in Residental Home Wiring

Author Kelly Smith  Mar 18, 2008

Sourse http://home-electrical.suite101,com/article.cfm/electrical ground fault protection

 Ground fault circuit interrupter (GFCI) receptacles are required during home wiring installation by licensed electrical contractors by standard building codes.
        What is electrical ground fault and why is it needed? Some things are just facts of nature. Just as water always seeks its own level in a water level, electricity always seeks the most efficient way to go to ground. That's why large buildings use grounded lightning rods for lightning protection. When it strikes, the lightning rods on the higher levels of the building direct the electrical current to ground, bypassing the building.

 It's the same thing with the home's electrical wiring system. An example is when a bare electrical wire inside a metal food preparation appliance comes in contact with the metal case. Now the metal case of the appliance is electrically energized. Now suppose the cook touches the appliance with one hand and the sink faucet, which is grounded, with the other hand. Now potentially lethal current will flow through the cook. The cook becomes the shortest route to ground. To prevent this, GFCI (Ground Fault Circuit Interrupter) receptacles are used.

 The GFCI constantly monitors the circuit it's on. When an impending electrocution emergency is detected, the receptacle instantly breaks the circuit. The household member will probably still receive a shock, but it won't be life-threatening.

 Where in the Home are GFCI Receptacles Needed?

 These receptacles are needed in certain circumstances, and in fact, electrical building codes require them. The common denominator is any environment where water, moisture, or the elements are present. This includes bathrooms, kitchens, outdoor lighting applications, garages, crawl spaces, and unfinished basements.

 These code requirements are specified by the National Electrical Code. All homes are not completely up to code, however, because the different living areas have been added to the code incrementally. For instance, outdoor receptacles were added to the NEC in 1973 and unfinished basements were included in 1990. Oddly, installing GFCI receptacles when wiring kitchens wasn't added until 1987.

 Any homeowners that are not fully up to speed on GFCI receptacles, should consider installing them. They are very inexpensive, but human life is priceless.

Testing Ground Fault Interrupters

 Like home smoke detectors or fire extinguishers, ground fault interrupters should be tested for functionality on a regular basis. The government recommeds testing them after first installing them, and then every month thereafter. Here are the steps -

There are two buttons on the GFCI; Reset (usually red), and Test (usually blue). First, plug a light into the receptacle. It should light up.

Press the Test button.

The light should go out, and the Reset button should pop out.

If Reset pops but the light stays on, the receptacle is likely wired wrong. It should be rewired.

If Reset doesn't pop out, this is a signal that the GFCI is defective; throw it out and replace it.

If everything tested properly in step 3, everything's fine. Press Reset and repeat next month.