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Need help adding double-switch to existing wiring, please!

Need help adding double-switch to existing wiring, please!

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  #1  
Old 06-20-15, 11:30 AM
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Question Need help adding double-switch to existing wiring, please!

Thought this would be easier. I had 2 switches: one for hall light, one for attic light. I'm combining the attic light with a new switch for some floodlights, using a double switch (top/bottom). I noticed that this switch has a connecting tab on the left side, between the upper and lower switches, by the way.

Here's where I'm stumped. The hallway switch is wired with 3-wire for unknown reasons. Bottom pole is red wire, top is black. The top pole also has a jumper running to the top pole of the attic light switch. Bottom pole of attic light switch is black lead to light. Both whites are connected together. Here's a visual:

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So, can anyone make sense of this for me, and tell me how to wire the new double-switch? I started connecting it, but stopped because something seems wrong.

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I'd sure appreciate any help you can offer. Thanks.
 
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Last edited by flukeslapper; 06-20-15 at 01:59 PM. Reason: updated photo
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  #2  
Old 06-20-15, 12:32 PM
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The hot wire from the left switch goes to the brass colored screw with the bridge, as you have it. The attic black wire will go to one of the silver screws on the other side, and the flood light black will go to the other silver screw. If there is a tab, it should be broken on that side to separate them. All neutrals go to the neutral bundle. That is really an old double switch. Did you find it in the garage or something?

I can't address the two wires (black and red) under one screw except to say one screw, one wire. You may need to find what they control.
 
  #3  
Old 06-20-15, 01:11 PM
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Thanks a bunch, Chandler! First, let me say that what looks like a red and black on one screw is not. Only the red wire from the hall light is attached to the bottom screw on the left switch. The black wire from the hall light is attached to the top of same switch, and then looped to the other switch, on the side with the tab (left). The right side of the double switch has no tab. Here's an updated image:

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Now, for an even trickier issue: I ran my tester around the wiring, and discovered that not only is the black lead from the attic light hot, but the white lead is showing hot, too! I did that test with the whites still bundled. Should the white wires be showing hot? Sorry, but I'm obviously not an electrical expert.

As for the switch, I found it in my box of electrical switches. Had another, but it was a Decora, and I didn't have a faceplate handy. Should I use the newer switch?
 

Last edited by flukeslapper; 06-20-15 at 01:41 PM. Reason: added photo
  #4  
Old 06-20-15, 02:09 PM
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I ran my tester around the wiring, and discovered...
Nothing if it is a non contact tester. They are only a general indicator usable voltage might be present not that it is. For measuring voltage you need to use a multimeter, preferably, analog (or a neon test light or a solenoid tester).

Voltage measurements are made between hot or ground and the wire being measured. Wire being measures must be disconnected. When you started were all three whites connected together and only to each other?

Only the red wire from the hall light is attached to the bottom screw on the left switch. The black wire from the hall light is attached to the top of same switch
What I suspect is power comes in on the 3-conductor cable but we will need a voltage reading between the black and white of the three conductor cable and the white and red of the 3-conductor cable to determine that.

Without tests and based on this statement
The black wire from the hall light is attached to the top of same switch, and then looped to the other switch
I would
  • Connect all whites together.
  • Trim off the second portion of the 3-conductor black wire and connect to two pigtails.
  • Connect one pigtail to the simplex switch.
  • Connect the other pigtail to the tab side of the duplex switch.
  • Connect the red to the other screw of the simplex switch.
  • Connect one of the remaining black wires to one of the screws on the side of the duplex switch with no tab.
  • The remaining black wire to the other screw on the side of the duplex switch with no tab.
  • Connect grounds per code.
 

Last edited by ray2047; 06-20-15 at 02:29 PM.
  #5  
Old 06-20-15, 02:48 PM
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Ray, thank you so much for that detailed response. I did use an analog tester on the wiring, but I re-tested, based on your suggestion. I tested a bit further, too. Here are the confusing results (Yes = hot):

For the 3-wire going from hall light to left switch:
Black and white: Yes
Black and ground: No
Red and white: No
Red and ground: Yes

Tested the white leads from the hall light and the attic light to ground:
White to ground (hall light): Yes
White to ground (attic light): No

This, of course, baffles me. Hopefully, you can help make sense of it. Thanks again!
 
  #6  
Old 06-20-15, 03:05 PM
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Were the wires disconnected when tested? We probably need to know the connections at each light also.
 
  #7  
Old 06-20-15, 03:34 PM
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The black and red were connected to the switch, but it was in the off position (both switches were off). The white wires were disconnected (separated). Ground wires were bundled. If you think that it makes a difference, I can disconnect everything and test again. Can't see how that would change anything, but I'm not the electrician! :-)

The connections at the lights will take some work to document, since I haven't removed the fixtures.
 
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Old 06-20-15, 03:45 PM
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You say the white wires were just disconnected and left to air out?? Were they ever connected to a switch? You should not have any power on a white wire except in a switch loop situation. That's what we're trying to figure out.
 
  #9  
Old 06-20-15, 03:51 PM
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Chandler - yes the whites were un-bundled and tested individually. The original two white leads were connected with a wire nut when I opened the box, not connected to either switch. Pretty crazy, huh? I wasn't expecting either of them to be hot, either.
 
  #10  
Old 06-20-15, 04:10 PM
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The black and red were connected to the switch, but it was in the off position.
Even off the red if it goes to the light can feed through it and maybe give a false reading. Try it with the wires disconnected to the white and ground (disconnected) of the 3-conductor cable.before opening the lights.
 
  #11  
Old 06-20-15, 04:56 PM
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Makes sense - I'll give that a try next. Thanks for sticking with me on this.
 
  #12  
Old 06-21-15, 08:03 AM
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OK, disconnected everything in the box. Here's the result:

3-wire to hall light:
B to W: Yes
B to Grd: No
R to W: Yes
R to Grd: Yes
B to R: Yes
W to Grd: Yes

2-wire to Attic light:
B to W: No
B to Grd: No
W to Grd: No

So, I'm guessing the black loop to the Attic switch was providing the power to that light, correct? The amount of hot connections on the Hall wiring has me puzzled, for sure.
 
  #13  
Old 06-21-15, 08:23 AM
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The amount of hot connections on the Hall wiring has me puzzled, for sure.
Add me to the confused list. I suspect the hall was originally set up as a 3-way circuit. Did the hall switch have "off" and "on" and only two screws plus ground? Is there another switch in or near the hall that doesn't work?
 
  #14  
Old 06-21-15, 09:16 AM
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To my knowledge, there have never been any 3-way switches in the house. This situation has become troubling enough that I am going to relocate the new switch wiring to a different location, and cut in a new switch box for it. Since it's on a different circuit, I want to avoid entangling it in what's apparently some kind of mess already. The wiring from the floods has a normal hot black lead and a white common, so I'll just mark the white accordingly at the switch, and keep things simple. Worth the extra work. Thanks for trying to sort this out with me. When I get it figured out, I'll update this thread.
 
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