Grounded wiring in electrical circuits provides a safe path to the Earth for electrical current. Bare copper ground wires are connected to posts on electrical outlets within their respective circuits. The ground wire is then routed to the grounding bus terminal in the main electrical panel of a home. The main panel has a ground wire leading directly to a rod placed in the Earth. When an open ground condition exists, safety is compromised. The do-it-yourself homeowner can locate an open ground in a circuit in 10 minutes or less.
Locate all the electrical outlets in the home.
Unplug any appliances from the outlet that will be tested.
Insert the tester into the outlet. Be sure the tester is fully seated in the receptacle.
Check the three indicator lights on the tester to determine the condition of the circuit. If the middle is illuminated and the two on either end are not, this indicates that an open ground exists.