Which wire is which in my switch?

Old 12-30-22, 01:27 PM
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Which wire is which in my switch?

I have an existing switch that controls a ceiling fan and light. I would like to move the location of the switch. In the switch there are two Romex coming from the pig-tail. One of the Romex continues the house current and travels on to the next location, the other one controls the ceiling fan. How can I determine which is which?
Old 12-30-22, 02:50 PM
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If there are only two Romex cables in the switch box then one cable is the hot coming into the box and the other is the switch leg going to the fan/light. You can determine the hot cable using a meter and measuring AC voltage between hot and neutral (the white wire). When the switch is off you will only get 120 volts between the hot and the neutral wires. The other black wire will have zero volts between the black and neutral.

If this doesn't make sense, or I am not understanding your description, please post a picture of the switch box with the wires exposed.

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