Two switches one light - lost my way.

Discussion in 'Electrical and Wiring' started by John, Jul 11, 2006.

  1. Jul 11, 2006 #1

    John

    John

    John

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    Hope you can help me sort this one out please. .

    Doing some volunteer work at small sanctuary - replacing a single light fixture in passageway with a switch at either end.

    Should have been a simple job reconnecting wires to the new fixture in the same order as connected to the old one (there are three white wires + one black. There is a red wire running through the box but it was not connected to the light fixture so I did not touch it. None of the white wires has a black mark denoting it is carrying live curent).

    Just as I disconnected the fixture two dogs got into fight, when I scrambled down to separate them I forgot what was attached to what.

    The more I tried putting things back together the more confused things got. I tried hooking up in various ways, but obviously not the right way as the breaker kept popping out.

    A simple job has become a nightmare.

    Any suggestions how to tell what wire goes where please?

    John
     
  2. Jul 11, 2006 #2

    Square Eye

    Square Eye

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    In a three-way switch there should be a powered switch (Line switch), and a Load switch. Then there are two travelers that the current switches back and forth to. The red wire must be one of the travelers. Leave it alone.

    You will need a meter to figure out the rest. You didn't mention if there was a ground wire up there. If there is, then the diagnoses will be much easier.

    Attach one lead to the ground, put the meter on voltage and find power. Mark that, or those wires. Flip one of the switches, recheck for power, mark the wires with power. Flip the other switch, recheck again for power. Turn the meter to ohms, check the wire that does not have power. That should give you a reading. If it does, then that is your neutral. Tie the rest of the wires , one to the light, the other two together. You may have to try a few different combinations, but you will find it.


    If no ground, keep your meter on voltage. you will notice that two or three wires will have voltage then not have voltage when the switches are flipped.
    It will be harder to determine neutral from a traveler without a ground.

    There is no way to just identify the wires by the colors in a switch circuit. You will have to have a meter. The only other tip I have is that if there is a 2 wire coming into the box, it could be a line feeder or an extension to another light, load. If there is only the one light on that circuit, then that is most likely your feeder and your neutral is the white.

    WHOA!! I just noticed that you are in Canada! You'd better get a meter before you get KILLED! Does Canada have a code?
     
  3. Jul 11, 2006 #3

    Square Eye

    Square Eye

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    Here's the best link I could find;

    http://www.mccarthyplace.com/hobbies/three_way.html

    This looks somewhat like what you described.
    [​IMG]

    There's a black connected to a white there, This is why I said that there is no way to tell what goes where.
    Eliminate the neutral, then you can better figure it out.
     
  4. Jul 12, 2006 #4

    JoeD

    JoeD

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    If you have three white you have three blacks.Where are the other two blacks? If they are together in the back of the box then you should be able connect the all white to the fixture white and the single black to the fixture black.
     
  5. Jul 14, 2006 #5

    John

    John

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    Thank you both for your help.

    We work on 120 volts here in Canadan and I do have access to a meter.

    I will check out the fixture (hopefully this weekend) and follow your advice now that I have an idea how this thing works it should get done.

    Again thank you both.

    John
     
  6. Nov 17, 2006 #6

    nh_handyman

    nh_handyman

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    Just an FYI - I've dis-allowed image links to my site (I revamped things a bit) so you can't see the image in the above quoted post any longer.

    The direct link is

    http://www.mccarthyplace.com/hobbies/electrical/three_way_switch/

    Thanks,

    Brian
     
  7. Nov 17, 2006 #7

    Snoonyb

    Snoonyb

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