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How to Change the Polarity of House Wiring

Polarity in electrical terms describes the directional flow of electrons from negative (-) to positive (+). In house wiring reverse polarity in an electrical outlet is a condition that results from incorrect wiring of the electrical hot (+) and neutral (-) wires to an outlet. Electrical devices plugged into an incorrectly wired outlet operate, but the switch for the devices opens and closes the circuit through the neutral wire instead of the hot wire. You can correct the polarity with a few tools and electrical circuit knowledge.

Things You'll Need

  • Polarity tester
  • Screwdriver
  • Flat-head screwdriver
  • Voltage tester
  • Phillips screwdriver
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    • 1

      Unplug all devices from the electrical outlet.

    • 2

      Insert the polarity tester into the outlet and observe the LED indication. If the red LED is lighted and the center yellow LED is lighted, this indicates the polarity is reversed and must be corrected.

    • 3

      Turn off the circuit breaker assigned to the outlet circuit. Leave the lighted polarity tester in the outlet. When the tester lights turn off, you have terminated the power to the outlet.

    • 4

      Remove the polarity tester from the outlet.

    • 5

      Remove the outlet cover screw by turning it counterclockwise with a flat-head screwdriver. Remove the cover.

    • 6

      Test the outlet terminals with a voltage tester to verify that no power exists in the circuit. Place one probe on the brass terminal and the other on the silver terminal.

    • 7

      Remove the outlet bracket screws with a Phillips screwdriver. Turn the screws counterclockwise.

    • 8

      Pull the outlet from the electrical box as far as its wiring allows.

    • 9

      Loosen the side terminal screws. Do not loosen the bare copper ground post screw.

    • 10

      Remove the white neutral and the black hot wires from the side terminals.

    • 11

      Connect the black hot wire to the brass-colored terminal. Turn the terminal screw clockwise to tighten.

    • 12

      Connect the white neutral wire to the silver terminal and tighten the terminal screw.

    • 13

      Push the wiring and the outlet back into the box. Tighten the bracket screws clockwise.

    • 14

      Insert the polarity tester into the outlet and restore the power.

    • 15

      Check the LED indication on the polarity tester. The red LED should be off and the two yellow LED’s should be on. Two yellow lights indicate that the correct polarity exists.

    • 16

      Disconnect the polarity tester from the outlet.

    • 17

      Replace the outlet cover. Tighten the cover screw.

    • 18

      Repeat Steps 1 through 17 on all the outlets in the house wiring system.