If the middle light on the tester, along with the one on the right, are both illuminated, the circuit is grounded properly. The left light remains off.
Homes wired prior to 1960 and that have not been updated are likely to have ungrounded circuitry.
Electric outlet testers are available at most hardware stores and home centers.
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.
Max Stout began writing in 2000 and started focusing primarily on non-fiction articles in 2008. Now retired, Stout writes technical articles with a focus on home improvement and maintenance. Previously, he has worked in the vocational trades such as automotive, home construction, residential plumbing and electric, and industrial wire and cable. Max also earned a degree of biblical metaphysician from Trinity Seminars Ministry Academy.