Two lights on Two 3 way Switches...Only one comes on?

Discussion in 'Electrical Forum discussion & Blog' started by IPictureU, Apr 20, 2008.

  1. IPictureU

    IPictureU New Member

    Messages:
    2
    K here is my deal....

    I ran 12/2 from my panel to a 3 way switch....then 12/3 to a ceiling light and then to another ceiling light then to a wall mounted 3 way switch....(hallway if you were curious).....

    When I throw the switches...one light comes on...the second comes on for a brief second and then goes out (florescent lights).......

    Red Wire..runs the entire distance from Switch to Switch.
    Ground Does the Same...
    The White Neutral is what the Lights are wired into both one after the other in sync and only with the 12/3 wire...neutral.

    I realize that there are several ways to wire a 3 - Way switch configuation like this but I'm not sure if this problem is my wiring or just a bad flourcent light unit?

    Anyone ever wired a Switch - Light - Light - Switch in this way with only 12/3 wire?

    Thanks.....Jeff
  2. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    Well it sure ain't the light.

    No cause it just won't work wired like that.
  3. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT
    Should have ran a 4 conductor between the two lights... :)

    Next time, draw it on paper first...
  4. IPictureU

    IPictureU New Member

    Messages:
    2
    I was afraid of that......yep I should have checked with the experts first....Darn it....

    ~ Jeff
  5. Bob NH

    Bob NH In the Trades

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    Location:
    New Hampshire
    The best way to fix it is to connect one light in the normal way. Then run 12/2 from that light to the second one.

    Using that approach you can put as many lights as you want on a pair of 3-way switches.
  6. kd

    kd New Member

    Messages:
    207
    Run a 12-2wG from one light to the next light. The second light has no neutral. Do NOT try to use the bare ground as a conductor!!
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,831
    Location:
    Cave Creek, Arizona
    lights

    A 3 way switch has 3 terminals but your wiring could only connect to 2 of them. It appears that the lights are wired in series using the neutral wire, although even that does not seem logical, but is what your description implies. A wiring diagram might eliminate the discrepencies. Your wiring sounds like one I came across years ago with a DIY'er. He wired the circuit for multiple 3 way switches. When I told him he needed 4 way switches for the extra ones but that he only had the three wires that a 3 way switch uses. When I told he he needed a fourth wire for the 4-way, he asked if he could use the bare ground wire for the fourth one.
  8. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    Location:
    Central Florida
    Huh? .
  9. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    I didn't know that any 120 volt circuit had a neutral either!
  10. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Using a 4-way switch to allow more than 2 switches in a 3 way/4 way circuit doesn't require any more conductors. You can put as many switches as you want in the circuit using 3 conductors (not including the ground) to turn on the first controlled light that can be within the switch circuit or connected at either end. Then you run a 2-wire + ground from that controlled light to all other lights using branches and runs in the most convenient routing.

    The idea is to lay out the circuit to operate one light. Get that one working and go from there to all of the others.
  11. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT
    Way over some peoples heads....:D
  12. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,718
    Location:
    Central Florida
    Well, they are ceiling lights...
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,831
    Location:
    Cave Creek, Arizona
    4 way switch

    His switch was off line, rather than inline between the two three ways, so he had to have 2 traveler wires to the switch and 2 back to the second switch. He only used a 14/3 wg because that is what a three way switch would require. And I know how a 4 way switch fits into the circuit, which is why I could advise him as to his problem.
  14. Billy_Bob

    Billy_Bob In the Trades

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    422
  15. Billy_Bob

    Billy_Bob In the Trades

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    422
  16. BigLou

    BigLou New Member

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    138
    why use 12awg for a lighting circurt ? copper is expensive
  17. kd

    kd New Member

    Messages:
    207
    In simple 120 volt residential wiring, the white wire is called the grounded conductor. In 240 volt residential wiring, the white wire is called the neutral conductor. Technically speaking, in a simple 120 volt circuit there is no neutral conductor.....However, sometimes people get confused because the bare wire is properly called the grounding wire; the bare wire should not be called the "grounded" wire, even though it is "grounded" at the service box location. Is the bare wire grounded? Yes it is, but its name is "grounding." ....To simplify conversation, we call 120 volt wires: hot--neutral--ground. More accurately the names should be: hot--grounded conductor--grounding wire. But there is an exception: If you are working with multi-wire circuits, there will be two 120 volt circuits sharing a neutral. In this case, the white wire in a 120 volt circuit is properly called a "neutral." Crystal clear? or Clear as mud?
    Also, draw out the 3way-light-light-3way circuit wired with 14-3 (or 12-3). You will see that one light box is missing a neutral or missing a hot wire.
  18. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    But you said that this circuit wouldn't have a neutral.
  19. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    I might add that the white/neutral wire is the "nice-friendly" wire and the black/hot wire is the "mean-nasty" wire!

    If everything is wired properly and you accidentally touch the white wire, you should not get shocked. However if you accidentally touch the black wire, you will get shocked. (Wires coming from the breaker panel that is.)

    For this reason, the black wire is always switched rather than the white wire. This way if you turn off the light switch, then replace a light bulb and accidentally touch the metal on the ring of the bulb, you will not be shocked.

    Further protection is to wire the ring of the light bulb socket to the white or neutral wire. And the conductor in the center of the bulb socket to the hot or black wire. Then if you leave the light switch on (easy to do with a 3-way setup), you will not be shocked when touching the ring of the socket or the metal on the light bulb. You would need to stick your finger in the socket and have the switch on to be shocked by the hot center conductor.

    This is the reason table lamps have plugs with one blade larger than the other on the plug. This makes sure the ring of the socket is connected to the neutral and the center connection of the socket is connected to the hot. (Safety)
  20. AnthonyL

    AnthonyL New Member

    Messages:
    6
    Location:
    Providence, RI
    What a great site!

    I read the various replies to your original question and it doesnt seem like a reasonable "fix" was found? Maybe there was, it just seemed like there were many tangents . . .

    If you can replace the 12/3 between the two lights with 2 12/2, your problem will be solved. As far as running a 4-conductor wire, good luck finding it without going to an electrical supply house and it will be pricey. Using the 2 12/2 will result in one of the white wires needing to be 'hot.' But, unless there was a change in code that I dont know about, this is ok as long as you make a turn of black tape on the white wire indicating it is being used as a 'hot' wire.
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