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=== grounded versus ungrounded ===Homes built prior to the early 1960’s were most commonly wired with a two-wire system, absent of the modern third wire being an equipment ground wire. The first requirement for grounded receptacles in residential construction dates back to 1951 when the NEC (National Electrical Code) required laundry areas to have grounded receptacles. * Electrical devices that can be used with non grounded receptacles are: lamps, radios, power adapters, toasters, vacuum cleaners and any item that the cord does not have the round third prong.* Electrical devices that require a grounded receptacle (equipment ground) are: high-end appliances, computers, TV’s, stereo equipment, power tools, surge protector strips and any other electrical device with the cord having the third prong.When three prong receptacles with open grounds are identified and a two-wire system is present in a home, the NEC currently allows the following methods to be used to resolve the problem: * Install an equipment ground. (recommended for high end equipment, see previous comments)* Provide GFCI protection for the receptacle (either at the receptacle or upstream of the receptacle) the receptacles are to be marked “no equipment ground”. This method does not provide an equipment ground.* Replace the existing three-hole receptacle with a two-hole non-grounded receptacle.=== Polarized Plugs ===Polarized plugs have two different sized slots, the neutral is the larger slot, this allows for a device to be plugged in, in only one manner insuring correct polarity. Reversed polarity is when the common and hot wire is reversed on the receptacle; when this occurs the large blade receptacle is now hot rather than neutral.As an example a lamp is plugged in with the polarity reversed, the exterior metal light bulb socket is “hot” at all times. In this instance when changing the bulb or touching the exterior of the socket the individual can be shocked. Reverse polarity is a safety issue.=== GFCI Outlets ===Ground Fault Circuit Interrupters (GFCI’s) are intended to protect the individuals using an electrical device particularly in a wet area. They are the receptacles with a black and red button, test and reset. It works by being tripped when sensing current leak/imbalance in turn shutting of the power to the electrical device.