Electrical Questions Answered: What Is A Gfci Receptacle Anyway?

By Author: John Jassmann
Total Articles: 16
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So you arrive home after a long day at work to find that old refrigerator in the garage has defrosted and most of its contents are now ready for the trash. Your frustration increases after further investigation reveals the reason you are now throwing away your grocery's points to the tripped GFCI receptacle the refrigerator is plugged into. Your first reaction may be to blame this minor disaster on the receptacle itself or possibly even consider replacing it with the regular type recepical you are used to seeing almost everywhere else in the house. Before you decide to make this dangerous mistake let's take a look at what a GFCI receptical is and how it may have just saved your life.

The idea behind detecting a ground fault is simple. When you plug an appliance into a wall socket, the appliance is energized by the two flat prongs on the power cord. The smaller flat prong is called "Line" and the larger "Neutral". On three prong cords the third round prong is for safety ground. When the appliance is in use, power flows to the appliance through the "Line" prong and returns through the "Neutral" and the power is considered ...
... in balance and safe. When a problem occurs with the appliance, like a hair dryer is accidently dropped into a sink while the water is running, the power now flows in through the "Line" prong as before but some of the power returns through the "Neutral" prong and some travels through the water to ground. The power is now out of balance and is considered unsafe and we all know what could happen if we reach into the sink to retrieve the dryer. A small electronic circuit has been designed to monitor the flow of power and will disconnect the electricity from an appliance
very quickly when an unacceptable power imbalance occurs. GFCI outlets have this small electronic circuit built into the housing and are the most common device used but there are GFCI breakers and adaptor cords as well.

If you take a look at any of the GFCI devices you will notice two buttons. One labeled "Test" and the other "Reset". The "Test" button applies a small imbalance to the circuit and should disconnect the outlet power instantly. I say should because the safety circuits could possibly fail allowing unsafe conditions to exist. Develop a habit to test all the GFIC devices on a regular basis and the test is very simple to perform. Plug any small portable appliance, such as a lamp or a radio, into a GFCI receptacle and turn it on. Then press the "Test button and the appliance should shut off. Press the "Reset" button and the power will be restored. Good to go!

If a GFCI outlet is tripped, ascertain why before resetting it. Let's take the old refrigerator in the garage for example. A wire may have worn through the insulation and is shorting to the metal frame. This could deliver a lethal shock to whoever touches the appliance when the reset button is pressed. If in doubt, call an electrician to troubleshoot the problem.

Over the years, GFCI outlet installations have been mandated by electrical and building codes in locations like kitchens, bathrooms, garages, unfinished basements, crawl spaces, and outdoors. Also special requirements are in place for hot tubs and pool equipment. While older homes have not been required to upgrade existing receptacles in these locations, it's a good idea to consider the safety aspects.

Be aware that you can still be shocked by a ground fault associated with a GFCI outlet. The outlet will detect the imbalance in power quickly enough to prevent a severe or fatal shock, but you will still experience a shock in the fraction of a second it takes for a GFCI outlet to respond.

John Jassmann owner of www.phoenixpdx.com The best Portland Electrical Contractor you can find in the Portland area. We provide a full range of electrical services from minor residential repair to large industrial fit-ups. Call 503-231-8006 for a free quote.