Wiring a new receptacle from an existing switch box

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Old 01-03-17, 09:53 AM
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Wiring a new receptacle from an existing switch box

I'm trying to wire a new receptacle off of an existing switch box, and my first attempt fell flat on its face.

The previous setup (before I added the new receptacle) had one 3-conductor cable into the switch box. Black, white, and green were connected to the switch. Red was capped inside the box.

My first attempt (sorely misguided with the benefit of hindsight) was to connect two jumpers to black, white, and green each from the 3-conductor cable. One set of jumpers went to the switch, the other extended out the box to the new receptacle in a new run of 2-conductor cable.

With this setup, the receptacle was dead with the switch ON, and showed an open ground with the switch OFF.

The black wire in the 3-conductor cable is hot.

After my first attempt failed, I got online and looked into switch wiring designs. Based on the fact that the box originally contained just one cable, I think it's wired with a switch loop from the light. I'm not clear on why I have no power to the new receptacle when the switch is on. I think the solution is going to involve adding the red wire into the design, however, as well as possibly re-configuring the wiring from that 3-conductor cable at the light location. Having trouble figuring out the specifics though. I'm hoping someone here can point me in the right direction.
 
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Old 01-03-17, 10:04 AM
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When wiring a switch loop with a 3-wire cable the red and black conductors are usually used and the white is capped off and not used. The white then can become the required neutral at a later date if needed. I believe you can probably open the ceiling box, use the red wire to replace the white in the switch loop and then connect the white to neutral in the ceiling box. That gives you the neutral in the switch box you need.
 
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Old 01-03-17, 11:38 AM
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I believe you can probably open the ceiling box, use the red wire to replace the white in the switch loop
This is the basic circuit Joe is sugesting you convert to.

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So your final wiring would look like this.

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Last edited by ray2047; 01-03-17 at 11:57 AM.
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Old 01-04-17, 08:44 AM
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Thank you, Joe and Ray, for the advice and diagram - they were very helpful! I opened up the ceiling light and reconfigured the wiring there and at the switch. I have power at the new receptacle now, whether the switch is off or on. That's the good news. The bad news is that the receptacle is still reporting an open ground condition. If I'm not mistaken, this means I have a loose ground connection somewhere in the path, which leads me to my next question...

I should get the same reading on my multi-meter when testing from hot to neutral as I should when testing from hot to ground, correct? At the ceiling light location, I'm only getting a reading when testing hot to neutral. Hot to ground shows nothing, which I think indicates that the open ground is either in the ceiling box, or farther upstream on the circuit. I'm hoping you can confirm that theory for me so I don't waste time troubleshooting in the wrong direction.
 
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Old 01-04-17, 10:03 AM
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I should get the same reading on my multi-meter when testing from hot to neutral as I should when testing from hot to ground, correct?
Yes.
At the ceiling light location, I'm only getting a reading when testing hot to neutral. Hot to ground shows nothing, which I think indicates that the open ground is either in the ceiling box, or farther upstream on the circuit.
That is correct. Determine what else is on that breaker. Do the receptacles on that breaker have a ground?
 
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Old 01-04-17, 10:04 AM
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Hot to ground shows nothing, which I think indicates that the open ground is either in the ceiling box, or farther upstream on the circuit.
If the open ground were in the ceiling box you'd probably be able to see that it wasn't connected in that box. I believe you'll eventually find the ground not connected somewhere upstream from the ceiling box. It's also possible that grounded NM cable was used to extend an older ungrounded circuit.
 
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Old 01-04-17, 06:29 PM
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Determine what else is on that breaker. Do the receptacles on that breaker have a ground?
Yes, they do. I just checked each of them and they all reported OK.

If the open ground were in the ceiling box you'd probably be able to see that it wasn't connected in that box. I believe you'll eventually find the ground not connected somewhere upstream from the ceiling box. It's also possible that grounded NM cable was used to extend an older ungrounded circuit.
Yep, I visually checked the grounds in that box last night, and tugged on them coming out of the wire nut and nothing was loose. I'm hoping I find the open ground elsewhere on the circuit, and that it's not an instance of an ungrounded original circuit. There are 8 switches and 5 lights that are all suspect at this point. Praying I find it closer to the beginning of checking all 13 and not on the very last one!
 
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Old 01-04-17, 08:19 PM
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Problem found and fixed. Will post more details tomorrow.
 
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Old 01-04-17, 08:42 PM
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We will be waiting to read what you found.
 
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Old 01-05-17, 07:20 AM
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Three of the lights on this circuit are three-way lights. One triple-gang metal box holds one of the switches for each of the three three-way lights. It has five cables running into the box. Only two of them were grounded to the box. The other three had the ground wires cut off just past where the cable sheathing was removed. This was a problem I ran into in other areas of the house in years past when replacing receptacles. In those instances I was able to add a ground wire jumper to get it connected properly. I did the same thing last night with the triple-gang box, and also replaced the existing "crimp + electrical tape" hot and neutral connections with these handy little five-conductor connectors.

I have a couple questions related to the grounding specifics, however.

First a few box wiring specifics:
-4 cables coming into the box from the top - referenced below as cables 1 through 4, numbered left to right
-1 cable coming into the box from the bottom - referenced below as cable 5

1) The two wires that were already grounded (from cables 2 and 5) were wrapped around one of the unused cable clamp screws in the metal box. Is this acceptable?

2) Due to the very short length of accessible ground wire in the other three cables (cables 1, 3, and 4), my options seemed very limited. I ended up putting a connector each on the ground in cables 3 and 4, connecting those two connectors together with a jumper, and then connecting one of those connectors to a new ground screw into the back of the box. I couldn't get the wires from cables 3 and 4 into a single shared connector - there just wasn't enough length to work with. I don't think this is an ideal setup, but I'm fairly certain it's acceptable.

3) I attached another connector to the short ground wire in cable 1, and then jumpered that connector to the same ground screw referenced in question 2 above.

4) None of the switches have anything connected to their ground screws. Some Google searching last night yielded mixed information on whether this is ok or not. I saw some comments that the switches are grounded via being screwed into the metal box. Is that correct?

After making all of those changes in the triple-gang box, I'm now getting a hot reading when testing hot to ground in the ceiling box, and I'm also not getting an open ground condition at the new receptacle now.
 
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Old 01-06-17, 12:03 PM
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Ok, something bizarre is now occurring, and it may or may not be related to the changes already made on this circuit.

Last night I re-installed the ceiling fan/light combo that I had removed in order to route a neutral to the switch box. Scatterbrained me didn't think to take a pic of the fan/light wiring before I disconnected it the other day, so I went off memory and logical deduction/testing in order to reconnect everything. This ceiling fan/light has two light sets, and the light pull chain has 4 modes. 1) both light sets off; 2) bottom light set on, top light set off; 3) bottom light set on, top light set on; 4) bottom light set off, top light set on. Before doing any of the recent work on this circuit, the top light set functioned correctly in this ceiling fan/light, as well as the matching one on the other end of the room. Reconnecting the wiring was rather straightforward except for the top light set. The top light set has two short white wires extending from it. The light set is basically a circle of night-light style bulbs. A two-wire cord runs from each night-light to the next, and terminates at the end of the circle. Presumably then one of the two white wires at the start of the circle is for power, and the second is for neutral, and it likely doesn't matter which is which, right? Anyway, there was a small orange wire extending up from the bottom light set and I discovered that this wire is hot in 2 of the 4 light pull chain modes - therefore it must be the hot line for the upper light set. So, connected it to one of the upper light set white wires, and connected the other upper light set white wire to neutral. No luck - upper light set doesn't work. Swapped the two white wires on the upper light set. Still doesn't work.

Opened up the matching fan/light combo at the other end of the room to see how it's connected. It's connected exactly how I re-connected the first one! Test the second one - upper light set doesn't work. I haven't touched any of the wires in the second one - just looked at them is all, but it's not working either now.

So long story short, the upper light sets are no longer working in either fan/light combo in this room. The only thing that has changed on the circuit is that some portions that previously were not grounded are now grounded. I can't see why that would have any bearing on the lights not working though. Hoping somebody can help me figure out what the issue is here!
 
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Old 01-06-17, 12:37 PM
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At the junction box a fan normally only has three wires, black, blue, white so I'm a bit confused. Can you post some pictures.
 
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Old 01-06-17, 06:46 PM
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Pictures!

In this picture the connections between the bottom light kit and the bottom light are shown. Also shown is the orange power that runs from the bottom light kit up to the top of the fan assembly.
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In this picture you can see where the orange power line connects to one of the two white wires on the upper light set. Also the other white wire from the upper light set, and it connects into a neutral connection, which itself connects to the main neutral line from the ceiling.
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Last is the incoming power from the ceiling, connected to the power feeding the fan and light kit below. You can also see one of the night-light style lights in the upper light set, and if you look closely you can see the white two-wire cord that connects each night-light to the next. It appears to be standard two-wire cord similar to a cord used in a plug-in small home appliance or light. It ends at the last light in the circle.
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And here's a crude drawing that represents the connections, minus the grounds. Ground connection is a green wire from the top of the fan motor connected to the ground wire from the ceiling box.
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Old 01-06-17, 07:01 PM
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I notice in your diagram you have fan black to house black. In my diagram it should be house red to fan black.

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Did the lights work correctly before?
 
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Old 01-06-17, 07:22 PM
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Yep, sorry. The house black in my pictures/diagram is actually just a black jumper that connects to the house red up in the ceiling. The red is entirely inside the ceiling box now and not visible in any of the pictures.

Yes, the upper lights worked before. And it's worth stating again that the upper lights also worked in the matching fan/light combo on the other end of the room, and I didn't change anything at all with that one, but the upper lights are not working there any more either. The only other thing that's been changed in the vicinity is fixing the open grounds in the nearby switch box.
 
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Old 01-06-17, 07:33 PM
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The wiring to the fan's switch circuit shouldn't have affected the lights. Tell me about the changes you made to ground in another box.
 
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Old 01-06-17, 07:40 PM
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See post #10 from earlier in the thread: http://www.doityourself.com/forum/el...ml#post2591421
 
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