Decommissioning Three Way-Switch

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  #1  
Old 01-23-14, 07:19 PM
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Decommissioning Three Way-Switch

I would like to decommission a three-way switch set up (two switches control a group of four recessed light fixtures). I'd like to use the space in one of the three gang wall boxes to control some new recessed light fixtures in an adjacent room. Can I just put wire nuts on the wires that used to be attached to one of the three-way switches? I assume I need to leave the dead-ended wires inside the box--correct? Will the remaining three-way switch operate the group of four lights normally? And then can I just go ahead and wire up my new circuit that includes the new recessed ceiling lights? If not, what do I need to do? We live in Massachusetts if that makes any difference regarding codes.
 
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Old 01-23-14, 07:28 PM
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We would need to know how the switch was wired. There are several ways to wire 3 ways.
 
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Old 01-24-14, 07:54 AM
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OK, not sure exactly what you need. If I observe which colored wires connect to what terminals on the switch in question will that be good enough? I'm not sure what else I can provide. This house is six years old if that helps at all with what wiring configuration may have been used.
 
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Old 01-24-14, 12:19 PM
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List all the cables (jacketed groups of individual conductors) or conduits entering the box, with colors in each, and what other conductors or devices they are connected to.

In other words, draw a diagram and upload it.

Or, if you can take very clear high-resolution photos that include:

1. A wide shot for perspective.
2. Another shot showing everything from a different angle. i.e. one left, one right.
3. A close-up of each switch showing how the cables are connected. The trick with this is making sure each switch can be identified using the "wide" shot.
 
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Old 01-24-14, 07:33 PM
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We need to find out where the power enters and leaves the switches.
 
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Old 01-24-14, 09:55 PM
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You can remove one 3-way switch and have the other one act as an on/off switch if you splice the wire that was connected to the common terminal on the switch you're removing to one of the wires connected to its traveler terminals and cap the other traveler wire.

If you add all of the wiring needed for a new 3-way switch into the existing box you may exceed it's fill capacity. You may need to replace the box with a larger one.
 
  #7  
Old 01-27-14, 11:41 AM
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More Info...

Okay, let's see if this is enough. The 3-way switch I would like to remove has 1 red and 2 black wires connected to it (plus ground, of course). With the lights on this circuit OFF, the red wire is hot and the two blacks are cold. The other 3-way switch also has 1 red and 2 black wires connected to it. With the lights still OFF the red wire and 1 of the black wires are hot, the other black wire is not. So I'm guessing this means the power is coming in from the other switch, correct?

Is there some way I can use the other switch as a simple on/off switch AND use the 3 conductor wire (plus ground) as a feed for the new switch I'd like to install? If that won't fly then how do I just remove the first 3-way switch and have the other 3-way switch control the existing lights?

If I need to provide more info let me know. These are both 3 gang boxes and there's a rats nest of wire in them.
 
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Old 01-27-14, 12:59 PM
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The 3-way switch I would like to remove has 1 red and 2 black wires connected to it (plus ground, of course). With the lights on this circuit OFF, the red wire is hot and the two blacks are cold.
Color of wire isn't important, it can vary depending on the whims of the installer. What is important is which wire is connected to the common (odd colored screw, usually dark gray). However here the 2-conductor cables are what is key to this. One is an always hot cable. As PCBoss wrote:
We need to find out where the power enters and leaves the switches
Answer that and we can help.

We need to know which wire connected to a common is hot when disconnected and measured to ground using a multimeter or test light but not a non contact tester.
 
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Old 01-31-14, 08:52 AM
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The wire connected to the common terminal on the 3-way switch Iíd like to get rid of (letís call it switch A) measures zero volts on a DVM when disconnected from the switch. The wire connected to the common terminal of the other 3-way switch (switch B) measures 120V on a DVM when itís disconnected from the switch. So the always hot cable feeds switch B. I donít know if this is important but switch B is also a dimmer.

Iíd like to keep switch B with its dimming capability (or replace with it a regular 2-terminal dimmer) and have it control the existing in-ceiling lights. Then Iíd like to replace switch A with a 2-terminal dimmer to control some new ceiling lights Iíll be adding. What do I need to do with the three wires that connect to switch A to make that happen?
 
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Old 01-31-14, 10:01 AM
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  • Disconnect and cap the red of the 3-conductor between A and B.
  • At B connect all whites together.
  • At B connect black of power in to the 3-conductor black and line side of dimmer (probably black - former common).
  • At B connect black of power to light to load side of dimmer. The wire designated for use as a non 3-way. See switch instructions.
  • At A white to white.
  • At A one black to each side of the switch.

Assumes current dimmer in B is convertible to single location use. You will have to check the dimmer instructions for that.
 
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Old 01-31-14, 10:36 AM
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That was quick! I hate to be a pain, but I wonder if you could translate your answer to reflect the following: My 3-conductor cable has 2 blacks and 1 red. The three way dimmer at B has 2 reds and one black. I could try translating but I'm afraid I'd end up blowing up a dimmer or worse. Thanks.
 
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Old 01-31-14, 10:43 AM
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My 3-conductor cable has 2 blacks and 1 red.
Cables do not have two blacks and one red. If it is conduit you will need to pull in a white. Attach to one of the blacks and pull the white in as you pull the black out. Use plenty of lubricant and be sure the other wires stay put. If you don't have conduit you have a white someone did a good job of recoloring black.
 

Last edited by ray2047; 01-31-14 at 11:04 AM.
  #13  
Old 01-31-14, 11:23 AM
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Iíd like to keep switch B with its dimming capability (or replace with it a regular 2-terminal dimmer) and have it control the existing in-ceiling lights. Then Iíd like to replace switch A with a 2-terminal dimmer to control some new ceiling lights Iíll be adding. What do I need to do with the three wires that connect to switch A to make that happen?...If I need to provide more info let me know.
Yes, we need more information. It's not possible to answer your questions with a reasonable degree of accuracy with the information you've given us so far. In general, remember that
Originally Posted by ray2047
Color of wire isn't important, it can vary depending on the whims of the installer. What is important is which wire is connected to the common (odd colored screw, usually dark gray). However here the 2-conductor cables are what is key to this. One is an always hot cable.
Here's what we need:

At box B, how many switches are there now? What type is each switch and what does it control? How many cables enter the box? How many wires, by color, are in each of those cables, and how is each wire connected? Where does each cable cable come from or go to? In particular, we need to know which wire is connected to the common terminal of each 3-way switch and which two wires are connected to its traveler terminals, which cable the power comes in on, and which cable feeds the load.

At box A, the same information.

These are both 3 gang boxes and there's a rats nest of wire in them.
Yes, but we need to be able to see the current setup as though we were standing there. Since you're the one there, we're dependent on your getting the information for us.

You already have one answer to what to do with the three wires attached to switch A:
Originally Posted by Nashkat1
You can remove one 3-way switch and have the other one act as an on/off switch if you splice the wire that was connected to the common terminal on the switch you're removing to one of the wires connected to its traveler terminals and cap the other traveler wire.
There may be other ways to do what you have in mind, and other ways to use the wiring you already have in place. We'll know more about that once we can see the existing system.

Iíd like to replace switch A with a 2-terminal dimmer to control some new ceiling lights Iíll be adding.
This brings up one more question: How many circuits are feeding the switches in these two boxes? What are the loads on those circuits now, and how mush load will your new lights add?
 
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