seeking advice for a three way

angalaluNovember 21, 2012

wiring situation..

I have a one day opportunity, before floors go down, to run some wiring beneath the subfloors and need to configure the following three way switch situation: switch (fed from a nearby outlet), light fixture, switch, light fixture, the end. I would like both switches to operate both of the light fixtures. I have some elementary knowledge of wiring, however, my B&D Home Wiring book does not cover this specific configuration and I can take a guess, but would prefer to have some advice from someone out there with better electrical wiring knowledge than self. Many thanks in advance.

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Frankly, if you're unsure about wiring a circuit it might best be left to a licensed electrican.

The following picture in pretty good assuming you are going to use NM cable (i.e., Romex). In your case the cable labeled "power source" would come from the nearby outlet. What the drawing doesn't show is the ground(ing) conductor, which needs to be maintained throughout the circuit. The second drawing shows the grounding conductors more clearly. Note that the ground(ed) conductor (neutral) goes only from the first switch (where the "power source" comes in) to the fixture.

    Bookmark   November 22, 2012 at 1:06AM
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Hi Mike, thanks for the response. I am actually not going to be connecting the wires. An electrician will be putting in the switches and the fixtures. My job is to get the appropriate cable run under the subfloor before the floors are laid (after which point, many holes will need to be made in walls that have been freshly smooth coated. The actual configuration is: light switch, light fixture, light switch, light fixture. So there is one more light that needs to be included in your diagram. The big question is: Do I need to include (2) 3 wire romex between each fixture?

    Bookmark   November 23, 2012 at 1:47PM
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You would extend the circuit from the first fixture to the second fixture with two wire cable (Romex). Without doing any fancy drawing I indicated the wire connections with the arrowed lines.

The rest of the wiring should not be changed.

    Bookmark   November 23, 2012 at 11:44PM
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thanks Mike! the 12/2 Romex can go directly from fixture to fixture, no need to pitt stop at 2nd switch location, correct?

    Bookmark   November 24, 2012 at 2:53PM
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I'm not that bright, but 12/2 is kinda large for a simple light circuit. 14/2 should be sufficient and a bit cheaper.

    Bookmark   November 28, 2012 at 3:33PM
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The gauge of the wire is predicated by the amperage of the circuit. Typically 14 gauge for 15 amps circuits and 12 gauge for 20 amp circuits.

There's some exceptions for fixture whips but I'm not sure we could call this one.

    Bookmark   November 28, 2012 at 10:20PM
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