Purchase a receptacle tester that has GFCI testing capability. Not all testers will indicate GFCI status, so check the package. Plug tester into the receptacle, just as you would plug in an appliance.

The concept of an outlet tester is pretty simple: plug the gadget into a suspect wall receptacle, and an array of LEDs light up in various patterns to alert the user to any wiring faults.

Locate the circuit breaker or fuse that controls the outlet you plan to replace and shut off the power to the circuit. Plug a lamp, radio or the GFCI tester into the outlet to test for power and ...