3-way switch wiring question


  #1  
Old 03-29-04, 07:29 AM
g_force_alt
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3-way switch wiring question - how to wire more than one fixture?

I've got an existing circuit with 3-pole switches and a single fixture (one light) and want to re-wire it to work with four, lower wattage lights. My wiring book doesn't say how to do this. It only shows how to reproduce what I already have. How do I wire in the other lights?

Power comes to one 3-pole switch through two wire Romex (black, white and ground). The other 3-pole switch is the end of the circuit. The existing light is between the two switches. At the light, the two reds are connected, the black from the first switch is connected to the white that goes to the second switch, and the white from the first switch and the black black that goes to the second switch are connected to the light.
 
  #2  
Old 03-29-04, 07:35 AM
J
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There are many possible solutions, but here is the simplest. Run new 14/2 cable (or 12/2 if on a 20-amp breaker) from the existing light to the additional lights. At the existing light, connect the black and white of the new cable to the same wires that the black and white of the existing light are connected to.

Be sure to carefully label all wires and record all connections at the existing light before you disconnect anything so that you can go backwards if necessary.
 
  #3  
Old 03-29-04, 07:45 AM
g_force_alt
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Can it be done using only the existing 3-wire?

I've opened the wall to reveal the 3-wire in each position that I'd like to add a light. I don't think I could fish a 2-wire to each position. Can the four lights be wired on the same 3-wire strand?

Thanks
 
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Old 03-29-04, 07:54 AM
R
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Your post does not make sense.

What do you mean that you've "opened the wall to reveal the 3-wire in each position that I'd like to add a light".

As John said, you don;t need to mess with the switches. You only need to run a new cable from the existing light to the firs locvation for a new light, to the next location for a new light, etc.
 
  #5  
Old 03-29-04, 08:25 AM
g_force_alt
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It would be easier to wire them all on the existing 3-wire than fish a 2-wire to each

The lights are wall mounted and spaced several studs apart. The cavity between the studs has horizontal blocking, making it impossible to fish wire in from above. Therefore, if I want to fish a 2-wire to each location, I have to open up the wall in several spots to drill through the studs.

The existing 3-wire passes within inches of each location that I want to wire a light. I've cut out holes in the walls where I'm going to put the boxes and can reach the 3-wire though those holes. If I can wire all of the lights on the same 3-wire I'm home free.
 
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Old 03-29-04, 08:28 AM
J
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Can the four lights be wired on the same 3-wire strand?
Sorry, no.

The cavity between the studs has horizontal blocking, making it impossible to fish wire in from above.
Not impossible. You just need a longer drill bit. It's done all the time.
 
  #7  
Old 03-29-04, 08:41 AM
R
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Your options are to replace the three conductor wire with four conductor wire, or to add a new wire that goes from the second switch to the first light, then to the second light, etc.
 
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Old 03-29-04, 08:52 AM
g_force_alt
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Thanks - that answers my question.

.
 
  #9  
Old 03-29-04, 08:14 PM
W
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Another option, which might be easier if you have access to _both_ switches from below (say if this were a first floor room and you could run wire in the basement)... You could run a _new_ 3 wire plus ground cable between the switches. If this option would work for you, post back and we can describe the proper connections to use.

-Jon
 
  #10  
Old 03-30-04, 06:54 AM
g_force_alt
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Thanks, I think know what you're going to suggest. It's the solution I came up with it yesterday after studying a wiring diagram. I plan to use the black and white of the 3-wire in the wall to tie all the lights together and run a new 3-wire between the switches from below. I'll then connect the black and white of the old 3-wire to the new 3-wire as if they were the terminals of a single light fixture.
 
  #11  
Old 03-30-04, 07:52 AM
W
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Exactly. Rather than run a new cable for the lights and use the old three way cable for the switches, run a new cable for the switches and use the old cable for the lights. Just be sure to cap off and mark as unused the cable from the last light to the second switch. If you can't pull the cable out of the wall, then you have to 'abandon in place'.

I like to wirenut all the wires from 'abandoned in place' cable together (white, black, red, bare). I then wrap white tape over the wire-nut and write 'aband' on the tape. This way there is no chance that the abandoned cable could be unknowingly energized from a buried junction box or other source.

-Jon
 
 

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