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-   -   Why is light switch hot whan it is off (https://www.askmehelpdesk.com/showthread.php?t=445378)

  • Feb 10, 2010, 08:40 AM
    angjas4x4
    Why is light switch hot whan it is off
    I have a light switch that runs 6 plugs and a fan when you take a test light and put it to the wires on the switch and the switch is in the off position it shows to be hot but if I turn the switch to the on position it turns on the fan and the plugs but I test the light switch it shows to be dead.
  • Feb 10, 2010, 11:59 AM
    tkrussell
    I suspect your applying the tester incorrectly. If you go across the two terminals of the switch in the OFF position, you have completed a series circuit, and will get a reading. Once the switch is on, your tester is now in parallel, and the switching is shunting the tester.

    To use a tester properly, for a 120 volt cirucit, test across one terminal to neutral or ground. With the switch off, one terminal will show 120 volts, and the other zero. With the switch On, both will show 120 Volts.
  • Feb 10, 2010, 12:20 PM
    donf

    Does this switch have a lighted handle?

    When you test with the switch in the "Off" or Open position, you are looking for the voltage between the Normally closed side of the switch and the Normally Open terminal. You should see a reading of 120 +/- volts.

    If you close the switch, there is no difference of potential because both terminals have the same voltage applied to them.

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