A handy circuit breaker finder makes this an easier job. It's a simple device consisting of a transmitter that plugs into the outlet you want to disconnect and a receiver you use at the breaker box. Just plug the transmitter into the outlet (figure A), or screw into a light socket using the light bulb attachment.
Now take the receiver out to the breaker box and move is slowly over the rows of breakers until it lights up, indicating you've found the switch for the outlet you're wanting to turn off (figure B). You should still test the outlet or switch with a voltage tester to make sure the power is off before starting repairs.
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