A receptacle ground is a connection between a power receptacle and the ground. Grounding is done to provide an exit path for electrons so that if there is a malfunction, the electrons will enter the earth, instead of people or equipment in contact with malfunctioning electrical equipment. This is a basic safety measure which is designed to reduce the risk of injury from an electrical system. When working with an electrical system, the ground should be the first thing connected and the last thing disconnected, whether or not the system is energized.
There are a number of ways to accomplish a receptacle ground. In most modern homes, the entire electrical system is grounded, and one merely needs to confirm that a receptacle is in contact with the grounding system. If an individual receptacle is not connected to the ground, it can be rewired to address this. It's easy to determine if the system is grounded, as there should be a copper stake somewhere around the house, often near the electrical box, driven into the ground and connected to a green wire.
If the whole system is not grounded, it is possible to set up an individual receptacle ground by connecting the ground wire on the receptacle to a piece of metal which comes into contact with the ground. For example, some people use abandoned metal piping or cold water piping for this purpose. In this case, it is important to confirm that the metal is firmly grounded, and to make sure that people are aware that the metal is being used as an electrical ground. This method may also not conform with the building code in all regions.
Another technique for a system which is not grounded involves the installation of ground fault circuit interrupter (GFCI) receptacles as a safety measure. The receptacle needs to be installed by an electrician or someone skilled with electrical work to confirm that the world is done properly. Certain types of wiring and receptacles are not designed to connect to a receptacle ground. These require some special installation techniques to make sure that they are safe. I
The purpose of a receptacle ground is to make a system safer. For this reason, it is important to periodically test outlets to confirm that they are still properly grounded. Testing devices for this purpose are readily available in locations like hardware stores, and some appliances actually light up when there is a problem with the ground on the receptacle they are connected to, to alert people to a problem.