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.

Grab a friend, a radio or a receptacle tester. Position a friend in the room with the tester, or plug in the radio and turn it up. Start flipping breakers one by one, stopping when you hear the ...

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.