Adding a receptacle the middle of a three-way circuit

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  #1  
Old 10-16-14, 08:47 PM
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Adding a receptacle the middle of a three-way circuit

(I did search the forum, but was unable to find an answer to this)

I have a three way switch that I believe runs fixture-switch-switch in my wife's sewing room. She would like an outlet next to the first switch.
Is this possible?
I opened up the boxes and the fixture and there is no common (red) wire running to the fixture, which leads me to believe that is where the power is coming in. The second switch is clearly the end of the run.

Is there a way to add this outlet?
Also, it's a 20-amp breaker, is a 15-amp receptacle against code here?
 
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  #2  
Old 10-16-14, 09:00 PM
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Fixture > switch > switch would not yield useable wiring.

At the switch where you want to connect.... what exactly is in that box ?
How many cables.....two or three wire ?
What color is on the three way switch common ?
 
  #3  
Old 10-16-14, 10:27 PM
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The box I'm looking at has two cables coming in. One is two-wire: black, white-taped-black and ground, and the other cable is three-wire: black, white-taped-black, a red common and a ground.
 
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Old 10-16-14, 11:16 PM
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Excellent job of describing what you have.

power > fixture > switch > switch ... is exactly what you have.

You have a two wire switch loop between the first switch and the fixture. Since you don't have neutral there you can't install a receptacle there.
 
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Old 10-17-14, 07:17 AM
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Ok, thanks for the clarification. I assume a switchable receptacle wouldn't be possible there either then, because I wouldn't mind that. If I wanted to make this happen, how could I do it, run new cable that bypasses the fixture to this box?
 
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Old 10-17-14, 07:58 AM
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She would like an outlet next to the first switch.
Is this possible?
Do you mean she wants a 2-gang box installed and have the outlet directly next to the switch?

You would need to run a new 2-conductor cable from source power (ceiling) to new box.

If you want to run the cable, post back for wiring instructions (at ceiling and wall) after that's done.
 
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Old 10-23-14, 03:29 PM
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Ok, I'll be running the cable this afternoon. I should be able to just splice it into the caps in the junction box above the light fixture and drop that down the wall to the 2-gang box where the receptacle will sit, correct?

Also, it seems likely that I'll need a 20 amp receptacle for this, since it's only one outlet that I'm wiring up and the breaker is rated for 20 amps.
 
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Old 10-24-14, 07:18 AM
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Hooked the new cable up and tested it with a receptacle tester. It says open ground. I connected the ground wire on both the fixture (where I spliced into the line to get power) and the receptacle. Is this a problem for use? Is it possible the whole circuit (otherwise all lights) is ungrounded?
Could I put a GFCI there instead?
 
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Old 10-24-14, 08:46 AM
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Won't really know the answer till you test with a multimeter.
 
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Old 10-24-14, 08:51 AM
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It is possible that the whole circuit is not grounded. Installing a GFI receptacle would certainly be one thing you could do but it would better to find where the ground is getting lost. The ground needs to be present at all locations.

You will need a volt meter to check for ground. You would check from the small slot to the ground pin or the plate screw. 120vac should be present.

Measuring from the large slot to the ground pin or the plate screw should be 0vac.
 
  #11  
Old 10-29-14, 01:36 PM
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You would check from the small slot to the ground pin or the plate screw. 120vac should be present.

With a multimeter, this shows 24v.

Measuring from the large slot to the ground pin or the plate screw should be 0vac.

This also reads 24v. This is on the new outlet that is the only thing on the cable spliced in at the light fixture. What's next?

Update: this information is with the fixture off. When the light is on, the readings are small slot to ground: 12v, large slot to ground: 36v.
 
  #12  
Old 10-29-14, 02:28 PM
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A standard 15 amp duplex can be used on a 20 amp circuit.
 
  #13  
Old 10-29-14, 08:51 PM
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You don't have 120vac at the receptacle which means you didn't connect it properly at the light fixture. You may have connected to the switch loop wiring.
 
  #14  
Old 10-30-14, 07:17 AM
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I do have 120v when I test small slot to large slot on the new receptacle with the multimeter. Just not when I touch the ground with either probe. My GFCI tester originally told me there was an open ground in the circuit.

It also occured to me yesterday when I was at the fuse box that this circuit is the same as the outlets in another bedroom that are all GFCI and read open ground.
Does this change the diagnosis? And can I replace this outlet box with a GFCI and use it safely?
 
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Old 10-30-14, 08:10 AM
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In post #11 you posted you found 12vac. That's what had me confused.

Apparently that is only a two wire circuit with no ground. If you want to put a three prong receptacle there then it will need to be a GFI receptacle.
 
  #16  
Old 10-30-14, 09:16 AM
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Code says you can't extend an ungrounded circuit because the the new wiring must meet code. You can not add a new receptacle there if it is ungrounded.
 
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