Low voltage at wall switch


Old 02-20-08, 10:52 AM
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Low voltage at wall switch

I have a four gang light switch box in my house which I recently purchased. One of the switches does not seem to work anything when it is switched on. I tested the voltage and there is only 40 volts coming to this switch, the other three work fine and have 120 volts. What are some causes for this low voltage?
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Old 02-20-08, 11:45 AM
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Originally Posted by abbub View Post
I tested the voltage
Between where and where using what type of tester?

and there is only 40 volts coming to this switch...What are some causes for this low voltage?
Probably "phantom voltage" from a digital meter. If you use an analog meter or simple neon bulb tester, you will likely see no power on the disconnected switch.
Old 02-20-08, 11:50 AM
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The 40v is meaningless, especially if you used a digital meter. If there is no neutral in the switch box you can't measure the voltage. If this box has switch loops there may be white wires but no neutral. If a white wire is connected to a switch is not a neutral (or certainly shouldn't be).

The switch may no longer be connected, or for a receptacle or in case it is needed at some future time for a ceiling fan and light.

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