Convert a two-prong outlet into a three-prong outlet by turning off the power at the fuse box, removing and replacing the receptacle, grounding the connection, then restoring power and testing the circuit. As long as the metal outlet box holding the outlet is grounded, it doesn't need to be rewired.
- Check to see if the box is grounded
Place one prong of a circuit tester in the shorter slot of the two-prong receptacle and touch the other to the screw on the cover plate. If the tester lights up, the box is grounded. If it's not grounded, an electrician should rewire it or install a ground fault circuit interrupter.
- Switch the receptacles
Turn off power at the fuse box, then remove the two-prong receptacle and detach the two wires. Attach the black wire to the brass terminal on the three-prong outlet and the white wire to the silver terminal.
- Ground the three-prong outlet
Obtain an 8-inch grounding wire and screw (available at hardware stores), and use the screw to connect one end of the wire to the back of the box. There's a threaded hole at the back for this purpose. Connect the other end of the ground wire to the green terminal on the three-prong outlet. Screw the new terminal back into the metal box.
- Use a circuit tester to check the circuit
Restore power and use the circuit tester the same way it was used in step one to be sure the circuit is working.