Having your home's wiring grounded is important in preventing power surges that can lead to fire or electrocution. A ground wire serves as the electrical current's shortest route back to the earth in the event that there is a break or interruption in the circuit. Determining if your house wiring is grounded is easy with a simple tool, but remember to always use caution when working with or around electricity.
Look at the outlets in your home. The first sign of proper grounding is whether you have two-prong outlets or three. A three-prong outlet has a narrow slot, a larger slot and a "U-shaped slot." The U-shaped slot is the grounding component.
Insert the circuit tester's red probe into the smaller outlet slot. This is the hot wire that provides the energy to the appliance.
Insert the black probe into the larger slot in the outlet. This is the neutral slot to complete the circuit.
Look at the indicator light. It will light up if the outlet is grounded. If it does not light up, reverse the red and black probes. If this lights up, then the outlet is grounded but was wired in reverse. If no light comes on in either test, the outlet is not grounded and should not be used.
Repeat Steps 1 through 4 in all the outlets of your home. It may be reasonable to think that if one outlet was properly grounded, all are. However, many older homes in particular have had a lot of work and renovation. Not all outlets may have been redone to ground the wiring.