Can I use a (mistakenly purchased) 3-way switch as a single pole switch?

Discussion in 'Electrical Forum discussion & Blog' started by Erico, May 21, 2012.

  1. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    It's a double (rocker/decora) switch I intend to separately switch two fixtures.

    There are three brass screws marked B1, A1, and A2. And two black "common" screws.

    I saw the electrician at my mother-in-laws kitchen job jump some wires to use a three way dimmer as a single pole. Just didn't watch him close enough.

    picture attached

    Attached Files:

  2. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Why would you need to jump anything...?

    Common and 2 travellers... If you switch to a traveller that connects to nothing, nothing will happen.
  3. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Use the common ( black terminal) and either of the other two.
  4. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    There are two commons and three other brass screws. I'm guessing either common for the hot-in and the A1 A2 screws out to the fixtures. Yes?
  5. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    You have 2 x 3-way switches built into one.

    Each of them has a common and TWO travellers...

    The TWO switches work INDEPENDENTLY.
  6. Chad Schloss

    Chad Schloss Member

    Messages:
    329
    Location:
    USA
    that is a decora 5641 switch. 1 way with a 3 way switch combined into a single gang. the a1 and a2 are for the 3 way switch portion, and the b1 is for the single pole switch. the switches separate at the mid portion of the switch. the b portion is the bottom of the switch. as was said, to use the 3 way switch, use either the a1 or a2 terminal, either one will work. if you have one feed in and you want that single feed to operate two switches, just hook to one of the common terminals (black screw). either one will do, since there is a piece of copper plate that joins the two together. if you had two feeds from different sources, then you would break that copper tab to separate the common terminals and each switch would have it's own feed and be independant of the other switch.
    Last edited: May 21, 2012
  7. Chad Schloss

    Chad Schloss Member

    Messages:
    329
    Location:
    USA

    Attached Files:

    Last edited: May 21, 2012
  8. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    The way I have it wired now is: hot wire from source in to one of the common (black) screws. Two wires out to the (2) separate fixtures. One of the two wires out is attached to A1 ..... the other is attached to A2.

    Seems to be working as needed.

    See any problems?
  9. Chad Schloss

    Chad Schloss Member

    Messages:
    329
    Location:
    USA
    when you flip the top switch (3 way), you will have power out to either a1 or a2, not both at the same time from what you described. a1 (or a2, your choice) and b1 is what you need to use both switches.
    Last edited: May 21, 2012
  10. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    OK thanks for your help. I thought it was working as needed but it's hard to tell until I hook up the fixtures. Climbing up and down the ladder with the circuit tester testing scenarios isn't easy. One fixture is going to be an outlet above the cabinets I built (for puck lights/down light and rope lights/ up-light) (see picture). The other fixture will be a display light in the center bay for art. (this pic was made before I drilled the holes).

    I'll switch to A1, B1

    Attached Files:

  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,491
    Location:
    Cave Creek, Arizona
    If you only have THREE brass screws, then you must have a combination single pole/3 way switch. We cannot tell WHICH screws do what, but B1 should be the single pole and A1 and A2 are the travelers for the 3 way. You can attact to either of the 3 way's terminals, but one will be on when the switch is turned up and the other will turn it on when the switch is down. Many dimmers can be single pole or 3 way, but they do NOT use jumpers to do it, you just cap off a wire.
    Last edited: May 22, 2012

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