A GFCI (Ground Fault Circuit Interrupter) is an Electrical safety device that measures the current flowing through the hot wire and the neutral wire. If they differ by even the slightest margin than the unit shuts down (trips). This prevents current from shocking a person near the receptacle. The GFCI can be a special panel breaker or a receptacle. The receptacle is the most common type of GFCI device and is identified easily by the Red (Reset) and Black (test) buttons.
GFCI protection should be located in the following areas:
All Bathroom receptacles
All Outdoor receptacles
Receptacles at swimming pools and spas
Kitchen counter receptacles within 6 feet of the sink area
Roof outlets, garages, unfinished basements or crawl spaces,, or just about anywhere else where you’re likely to encounter water or dampness.
In order to insure that GFCI receptacles are working correctly, manufacturers install Black (TEST) and Red (RESET) buttons. It is recommended that you test the GFCI once a month by pushing the TEST button. The RESET button should pop out and the power should shut off. The receptacle is placed back into working status by pushing the RESET button. If you have GFCIs attached to circuits without a ground then the TEST button will not work. You will need to purchase a GFCI from a Hardware store to test the ungrounded GFCIs. GFCI breakers should also be tested using their TEST and RESET button once a month.
If your home does not have GFCI protection, you should seriously consider adding this safety feature. Receptacles can be installed by an Electrician or a good Do It Yourselfer for a relatively small price.