understanding wiring

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Old 04-02-12, 12:00 PM
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understanding wiring

I have two banks of lights on either side of my medicine cabinet in my bathroom. It is run by a switch which is the top half of a switch/outlet combination receptecle. The switch has a tiny led? light next to it and is always on.When I pull the receptecle out of the box it has a red wire going to one side of the switch, a black wire going to one side of the outlet and a white wire going to the other side of the outlet there is no other wires in this box. Both the outlet and the switch work fine, the switch runs the bank of lights and the outlet runs my nightlight...what is the purpose of the led next to the switch? why is there three wires and no other?.... if I want to move just the switch to another location do I need to add add a 14/3 wire to it?....and lastly if after I move the switch can I just have two outlets instead? If so what do I use for powering the outlets?
 
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  #2  
Old 04-02-12, 12:25 PM
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The LED appears to be a power-on indicator.

Based on your description and standard practice, a best guess on the wiring of your switch/receptacle combo is:

black = hot feed
red = load feed to lights
white = neutral for the receptacle

To verify that that's correct, you need to kill the power, remove the combo and spread the wires apart, turn the power back on and test for 120 across the black and the white. If there's no reading there, test across the red and the white.

Assuming that the colors indicate the functions I listed, you can relocate the switch by extending a piece of 14/2 cable from the existing location to the new location. You would then re-designate the white wire in the new cable by coloring each end of it black with either tape or a marker. Splice the "white" in the new cable to the existing black wire and the black in the new cable to the existing red wire. In the new box, attach the "white" and the black from the new cable to the switch. Ground everything and close up the new switch.

To install a 2-receptacle outlet in the existing location, test the existing outlet for GFCI protection before you turn the power off. If there isn't GFCI protection, buy a GFCI receptacle and install it according to the directions that come with it. If there is GFCI protection back up the line, just install a standard receptacle.

Two tips: When you're finished, nothing should be connected to the LOAD terminals on the GFCI. And you can save some room in the older box by placing both the black feed and the "white" for the relocated switch under the brass screw for the LINE connection.
 

Last edited by stickshift; 04-02-12 at 12:30 PM. Reason: removed quoting of entire post
  #3  
Old 04-05-12, 09:57 AM
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Understanding wiring

Thank you very much...if I test across the black and white on the existing cable and get 120 volts does that mean that I just proceed with your instructions? Why then would I bother to test across the red and white wires? What if the black and white wires aren't 120 volts...then what do you want me to do? Lets assume I get 120v across the black and white, then I am to take the new relocating wire and "make" the white wire in it black and attach it to the existing black(hot) wire in my old location and take the new black wire and attach it to the red(load) wire in the old box. Then take the new "black" wire(hot)nd attach it to one side of the new switch and the new white wire(load) to the other side of the new switch and the lights should work? Why don't I need the old white wire for anything? Assuming it does work how do I test the wiring in the old box for gfci? Assuming that I don't have gfci protection there and I buy a gfci outlet.....you want me to take the old white wire(neutral)l eft in the old box and connect it to the new outlet recrtacle and the "black"(from the new wire) which is spliced to the old black wire in the old box and connect it to the line screw on the new gfci receptacle? I hope I explained myself clearly it is just a little confusing to this zmateur
 
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Old 04-05-12, 12:00 PM
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Hmm, maybe I wasn't as clear as I hoped to be.

how do I test the wiring in the old box for gfci?
test the existing outlet for GFCI protection before you turn the power off
or remove the existing combo receptacle/switch. Do that by plugging a GFCI tester into the existing receptacle. Read the LEDs on the tester for correct wiring, then push the button on the tester. If the power stays on you don't have GFCI protection up the line and you need to install a GFCI receptacle here. If the power goes off, you do have GFCI protection up the line and you need to install a standard receptacle here.

if I test across the black and white on the existing cable and get 120 volts does that mean that I just proceed with your instructions? Why then would I bother to test across the red and white wires
Just to be sure that the black is hot, the red isn't, and the white is neutral.

Lets assume I get 120v across the black and white, then I am to take the new relocating wire and "make" the white wire in it black and attach it to the existing black(hot) wire in my old location and take the new black wire and attach it to the red(load) wire in the old box. Then take the new "black" wire(hot)nd attach it to one side of the new switch and the new white wire(load) to the other side of the new switch and the lights should work?
Almost. It's the new black wire to the other terminal on the switch. White-tagged-black to one terminal, black to the other.

Why don't I need the old white wire for anything?
You do need the existing white wire. That's the neutral (we think) and it will be connected to the neutral terminal on your new receptacle. To the neutral LINE terminal if it's a GFCI receptacle.

Assuming that I don't have gfci protection there and I buy a gfci outlet.....you want me to take the old white wire(neutral) left in the old box and connect it to the new outlet recrtacle and the "black"(from the new wire) which is spliced to the old black wire in the old box and connect it to the line screw on the new gfci receptacle?
Yep. Connect the existing white wire to the neutral LINE terminal if it's a GFCI receptacle. Either add a black jumper wire into the splice of the old black wire and the new white-tagged-black wire and then connect that jumper to the "hot" LINE terminal on the new GFCI receptacle OR, to save space in the box and avoid having to fit a splice behind the GFCI, you can terminate both the existing black wire and the new white-tagged-black wire to the "hot" LINE terminal.

Clearer? I hope.
 
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Old 04-06-12, 07:31 AM
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OK I got it..thank you very much....you were clear, I am just a novice. I think the way I am going to go about this i am going to turn off power, disconnect the three wires from the old combo receptacle, turn power back on and check the existing black and white wire for 120v. If I have it there and don't have it between the old red and white, then I am going to connect my new relocation wire to the red and black of the old and hook up a switch on the end of the new wire and see if the lights work. Assuming they do, then I am going to install an new double outlet gfci receptacle in the old box using the left over old white wire and the old black/ new black combination and see if the outlets both are live. If everything is working, then I will button everything up.....sound good to you?
 
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Old 04-06-12, 08:06 AM
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Yes. One thought that has occurred to me is that you could minimize the risk of of overloading the existing box by extending the black and white wires to the new box and installing your new GFCI there. A pigtail from the black-wire splice to the the switch, with the red on the other terminal, and that mounts in the old box.

The reason that I suggest this is that there's a lot more room for splices and wire nuts behind a SPST switch than there is behind a GFCI. Unless you have a deeper-than-standard box in the wall now, everything might not fit with the GFCI there.

Just a thought - I don't know if this would put the two devices where you want them or not, although it would keep the switch where it is now.
 
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Old 04-06-12, 08:18 AM
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No good......

the entire reason for all of this is that the switch that turns on the lights in the bathroom is now located behind the door and not convenient,it needs to be on the opposite wall. The outlets however can remain behind the door because they are close to the sink and the mirror, where they should be. I am going to install a 2 gang box on the opposite wall, one switch for the lights and the other new switch will be for the exhaust fan. I am going to run the wire from the fan to the new 2 gang box...but I am not sure where I am going to get power to run it????????
 
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Old 04-06-12, 08:50 AM
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You sound like you already have power in the old switch box.
 
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Old 04-06-12, 09:20 AM
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I do but that is needed over there for the outlets..from the old box to the new I am extending the black(hot)black and the red(load)wire only to the new 2 gang to operate the lights...how do I provide power to a different switch to run the exhaust fan in that new box?
 
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Old 04-06-12, 09:29 AM
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You would add a pigtail connection to bring the power over to the new box. Adding the power to another location does not remove it from the original location.
 
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Old 04-06-12, 09:41 AM
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I am going to run the wire from the fan to the new 2 gang box...but I am not sure where I am going to get power to run it????????
This changes the picture. With the wiring we've talked about so far, you would have power, but no neutral for the fan.

You could extend your 3-wire cable to the new switch box and splice color to color in the existing box. Then you'd add a jumper to the white and the black splices to feed the new GFCI. But that would mean that you'd have three splices to cram into the existing box behind the GFCI. That's just not going to work unless that box is 4 inches deep.

Here's what's going on, I think. The power for this bathroom comes from the panel to the box behind the light fixture. From there, the existing 3-wire cable takes the power down to the existing combo, along with a red wire to power the light and a neutral for the receptacle. You can verify this by pulling the light fixture and looking at the connections there. If I'm right, You'll find a 2-wire cable and the other end of the 3-wire cable. The two black wires will be spliced together. The black wire for the light fixture will be spliced to the red wire from the 3-wire cables. All three neutral conductors - incoming, 3-wire and light fixture - will be spliced together.

There are a number of ways to skin this cat. I would relocate the existing 3-wire cable to the new 2-gang switch box, or run a new piece of 3-wire if the existing one isn't long enough. A new piece of 2-wire can be run to feed the receptacle, either from the light box or from the new switch box. Or, If you really want to have the new receptacle in the existing wall box and that cable's too short to reach the new switches anyway, you could leave the 3-wire cable in place, cap off the red wire at each end, and use the black, white and ground wires to connect the new GFCI.

In the new switch box, you use the black wire to feed both switches. Just add two jumpers to do that. The red wire would go to the second terminal of the light switch, the black wire for the fan would go to the second terminal of the light switch, the two white wires would splice together behind the switches and the ground wires would splice together with a jumper for each switch if you're using a plastic box. If you're using a metal box you can just ground it.

At the light, the 3-wire cable for the new switch box wires just like the old one did - add ground to the grounds, add neutral to the neutrals, add power - black - to the black power wires and splice the red wire to the black wire for the light fixture.
 
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Old 04-06-12, 10:20 AM
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Sorry I am really stupid but I am confused, I am already splicing the black wire( hot) from the old box to the new box to power/ run my lights. What color wire and where is it that you want me to pigtail to provide power for my exhaust fan.As I mentioned earlier I am running a 14/2 wire from my old box to this new one I am installing.I am splicing the 14/2 wire to the black( hot) and the red(load for lights) from the old box to a different new box and putting those two wires to either side of a new switch. What I want to know is how to get power to another switch that runs my exhaust fan that will be also be installed in the same new box that has the switch for the lights.....Help
 
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Old 04-06-12, 10:57 AM
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Regretting my lack of clarity

I'm in no position to comment on your intelligence, but I can certainly see how my advice may have been far less clear than I would have liked.

The new advice is don't add any new wire into the existing box. First, check behind the light fixture to make sure it's wired the way I described in my last post. If it is, there are two ways to wire your switches, one of which I already described. But the important point is to forget about adding and splicing wire behind the GFCI. I almost certainly won't fit and may not be code-compliant anyway.

I hope this is clearer.
 
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Old 04-06-12, 03:50 PM
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Well, maybe not so clear! I meant to say "It almost certainly wont fit..."
 
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Old 04-11-12, 10:29 AM
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Update on setup on wiring for lights/exhaust fan

OK here is the latest. First the wiring to the light bars is what you thought. The black and white are hot and neutral and the red is the load. Second, the box that had the switch/ outlet that controlled the lights is full of wires..not much room. The other box on the other side if the medicine cabinet where the second light bar is located, only has a black and white wire and tons of room, but that is not eligible to be used as it is not in a good spot. I am not going to use the same two light bars, but I am going hang a new light fixture in the same two spots. In the box that has the combo, there is already an unused 14/2 wire in there that I ran to the new location, so I know that I can splice into the black and red with it and put a switch on the other end and my lights would work, but I still would not have any power in the new location yo run my exhaust fan. I think if I add an extender to the old box, I might have enough room to replace the switch/outlet combo with just a regular outlet receptacle. I can also add an extends to the new location if that will help me in hooking up the exhaust fan. The reason shy I can add extender is because I hung drywall over the top of plaster, so I have to add extenders anyways. Does this help? Will whatever new lights I buy work with the existing wiring?
 
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Old 04-11-12, 11:19 AM
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I think if I add an extender to the old box, I might have enough room to replace the switch/outlet combo with just a regular outlet receptacle.
This can probably be done with a GFCI. I'm hoping, because you definitely don't want a receptacle in a bathroom that doesn't have GFCI protection. First, unfortunately, I need a little more information:

Does the old box have only the 14-3 and the 14-2 you ran? What is the depth from the face of the drywall to the back of that box? And how deep is your GFCI - from the back of the yoke to the back of the device? (I'm guessing 1 1/8" for that.) Thanks.
 
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Old 04-11-12, 12:22 PM
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The old box has only the 14/3 wire going to the lights and the 14/2 wire I ran from there to the new location. The depth of the old box is about 2 inches and the depth of gfci is 11/8 inches, but with an extender, the new depth of the box from the face of the drywall will be over 3 inches.
 
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Old 04-11-12, 03:21 PM
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The old box has only the 14/3 wire going to the lights and the 14/2 wire I ran from there to the new location. The depth of the old box is about 2 inches and the depth of gfci is 11/8 inches, but with an extender, the new depth of the box from the face of the drywall will be over 3 inches.
You could pack a lot of splices in the space behind your GFCI! But there's no need, it's not good practice and it would leave you with a couple of really hard-to-decipher wire runs. Here's what I would do:

At the light fixture(s), disconnect the red wire feeding the lights and cap it off. At the old box, remove that piece of 14-2 you ran. (Hang onto it, it'll be useful in a minute.) Cap off the other end of the red wire and connect the ground, black and white wires to your new GFCI - LINE terminal pair for the black and white, of course. You can then install the extension ring, mount the GFCI, and cover it. That's done.

Run a new piece of 14-3 from the light box - where the old one is - to the new switch box and wire it just like the old one: black-to-black, white-to-white and red just hanging. Whenever you want to, you can mount your new lights and wire them just like the old ones: tie their neutral wires into the neutral splice and splice their hot wires to the red you left hanging out. And yes, whatever new lights you buy should work with this wiring.

For the fan and the new switch box, install the fan and run that piece of 14-2 you salvaged earlier from the fan to the new switch box. Make up the wires at the fan and finish it up - cover plate, grille, whatever. Now that's done.

In the new switch box, you now have the 14-3 coming from the lights - and the panel - and the 14-2 from the fan. Splice the grounds and, if the box is plastic, add a couple of pigtails for the switches (if it's metal, ground the box with a pigtail to a ground screw). Splice the two white wires together. Fold the ground wires and the neutrals back into the box out of the way of the switches. Add two pigtails to the black wire in the 14-3 coming from the lights. Attach one of those pigtails to each switch. Attach the red wire to the second terminal on whichever switch you want to control the lights. Attach the black wire for the fan to the second terminal of the other switch. Install the extension ring, mount the two switches, cover them and turn the power back on.

That should do it. Test everything to be sure, then go have that cold one, or whatever reward you've chosen.
 
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Old 04-12-12, 09:45 AM
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If I disconnect the red( load) wire that feeds the old lights, and cap it off inside the old light box, what do I do with any wire or wires that were spliced to it? Do I need to run a ground wire to the new gfci outlet in the old box or can I just hook up the white and black wires? The old lights were wired with just a black to black and a white to white hookup from each light box. It is not going to be easy to run a 14/3 wire from a crowded light box to the new box location.
 
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Old 04-12-12, 05:53 PM
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Do I need to run a ground wire to the new gfci outlet in the old box or can I just hook up the white and black wires?
If you're saying there's no ground wire in the 14-3 feeding the old box, then don't remove the new 14-2 you ran from box to box. We'll use that to feed the GFCI.

I'm actually liking this path better. More later.
 
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Old 04-12-12, 10:07 PM
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If I disconnect the red( load) wire that feeds the old lights, and cap it off inside the old light box, what do I do with any wire or wires that were spliced to it?
Isn't the red wire the connection th the light load? Aren't all of the wires connected to it light fixture wires? If they are, they'll be connected to the new red wire. If not, what are they?

It is not going to be easy to run a 14/3 wire from a crowded light box to the new box location.
Even if you remove the old 14/3 entirely?

Here's my thought: If your existing piece of 14/3 has a ground wire and you have the walls open enough to do this, pull it out of the old box and run it to the new box. If it doesn't have a ground wire and you have the walls open enough, remove it entirely and run a new piece of 14-3/G to the new box. If it doesn't have a ground wire and you don't have the walls open enough to remove it entirely, disconnect it in the light box and, in both boxes, cut the individual wires back to an inch or so and cap each of them with the smallest wire nut that will do the job - a blue or gray should do it. Then run a new piece of 14-3/G to the new box.

Hook up the GFCI, using your new piece of 14-2/G coming from the switch box - ground wire to ground screw, black and white to the LINE terminals. Done.

Wire your new switches the way I described earlier - the two black pigtails, whites together, the red load for the lights and the black load for the fan. But, now, add the new piece of 14-2 going to the old box to the back splices.

Wire the lights the same as we talked about before too. Black from the 14-3 to the power feed, whites all together and red from the 14-3 to the black wires from the new light fixture. Wire the fan as before too.
 
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