Single pole switch with 3 sets of wires?

Old 03-26-18, 12:07 PM
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Question Single pole switch with 3 sets of wires?

I want to install a single pole dimmer to replace a single pole switch. The Switch controls 1 light however has 3 sets of white black wires. I can only assume that 2 sets are for pass through to other sockets located in the same room. How do I tell which ones are which and how do i wire the switch. Pictures are included. Thanks for all your help in advance.
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Old 03-26-18, 12:16 PM
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One of them is power in, one is power feed out to the rest of the circuit, and one of them is power to the light.

Separate the black wires and turn the breaker back on. Carefully test voltage on each of the wires to ground, and the one around 120V is your power in. Once that one is identified, turn the circuit back off and wirenut power in to one of the unknowns. Turn the breaker back on and either the light will come on, in which case you have identified the light power, or the rest of the circuit will come on in which case you have identified power out.

Now that the wires are all identified, put the light power on one brass of the switch. Wirenut together power in, power out and a 6" pigtail of black wire. Terminate the other end of the pigtail on the remaining brass switch screw.
Old 03-26-18, 12:53 PM
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Single pole switches say 'on' & 'off' on them. If this switch doesn't have that lettering it's a 3-way switch. Is there another switch that controls the same fixture?

Old 03-26-18, 12:59 PM
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3-way switches are single pole switches also.
Old 03-26-18, 09:00 PM
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In your picture..... the two black wires that were on one end of the switch are the two that get combined. The wire still on the switch is your load/light wire.

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