I have a upstairs / downstairs switch that controls a string of 5 pot lights and one fluorescent light. My goal is to take the final two potlights in this string and separate them from the string and wire them to their own switch, which I have an open space for in my switch box. I'm wondering if the power should come from the junction box to the light, and then from the light to the switch, or should it go to the switch first? So far when I turn the breaker on there is one of the two lights on and when I flick the switch the breaker trips.

Before you try to achieve your goal you must fix what you already have. The black, hot wire generally goes to the switch and then comes out of the switch to the string of lights. If you disconnect 2 lights to the string you no longer have a hot wire and that second switch opening will do you little good unless you can pull more cable through the ceiling, is it open above?

Yes, the ceiling is open and I have already fed additional wire. So the original string of lights now ends with light # 3. I am curious what the proper wiring should be now. Essentially I'm adding new lights so do I go to switch or to light first

Did you get your now string of 3 to work off the old switch, last I heard it was still tripping.

The original switches (up and downstairs) still operate the reduced string of lights just fine. It is the two leftover potlights that aren't working, and tripping the breaker. I've got wires to both the new switch and lights, but still tripping

Sounds more like one of the recessed lights is shorting. With your new cble connect to just one and then the other, bet only one causes a trip.

Hi guys...

Hmmm... using 3 way switches can be diffficult to work with in these cases.

It seems to me you need to get power over to the new switch or you could even feed into the light and then to the switch, but first you have to isolate the power from the 3 way switches.

It should go:

Isolate power from the 3 way switch... do not use a traveler wire as power... find which wire feeds power to the 3 way switches and then pigtail the wires (black, white and ground) BEFORE they feed power to the 3 way switches and connect the black from the pigtail to power the new switch. Connect the black wire from a new 14-2 wire to the switch and send the wire (black, white and ground wires) to the lights.

You can also work from a junction box, just need to get an isolated power source up there (separate from the 3 way switches).

That all make sense?

Mark

Three way switches can be tricky. You'll have a hot and a neutral and ground running through all the can lights and junction boxes but you might not have a neutral in your switch box at all. Often when running switches, the white wire is reused as a hot. When that's done, it's called a switch loop. It should be marked with black tape to indicate it's a hot as well. I drew the 2 basic 3 way configurations. In the first one, you would tap into the hot (black) to the new switch with a pigtail and then run a new wire over to the first light you want controlled by the switch... connecting the black from the new wire to the switch in the switch box and the white would be pigtailed to the white coming into the box from the line source. Then you would connect the lights black to black, white to white.

If you have a switch loop, you have a white wire in your switch box that is hot, not neutral and using that as a neutral will trip the breaker when you turn on the switch.

With a switch loop, only the hot is interrupted at one of the devices and sent to the switch and returned to the device.

If you have a switch loop, your options for wiring the new switch are to find the line source and tap into the hot and neutral and run them to the first fixture you want the new switch to operate. Connect white to white of the light fixture and to white of the wire leading to the next fixture. And don't connect the black. Run another length of romex back to the switch. Connect the white wire and black wires to the two screws on the switch. Wrap some black electrical tape around the white wire to redesignate the wire as hot. Back at the light fixture, wrap the other end of this runs white wire with black tape and connect it to the black wire from the source wire. The black wire from the switch run gets connected to the black wire from the light and to the black wire from the romex leading to the next light in the run.

Of course you need to be connecting grounds throughout all of this.

In the top drawing, the 3 way switch shows the white wire remaining a neutral throughout.

When wired as a switch loop, the white wire becomes the hot, returning it from the common screw in the second switch box back to the first where it is returned over the white wire as hot again.

Hope this drawing helps:

http://i2.photobucket.com/albums/y3/...3wayswitch.jpg

massplumber2008. I'm looking more at your second suggestion. To clarify, the switches at the top and bottom of the stairs now operate a reduced string of lights without issue. They are for all intents and purposes out of the picture.

The "new" switch and 2-light combo is in a different area of the basement and will branch off a different junction box. However, this junction box also feeds a dimmer switch which controls 4 previously unmentioned pot lights. So from junction box I have wiring feeding switch A (dimmer) and I now want to add switch B (simple on/off switch) to control 2 other additional pot lights. Up to this point when I had enabled the breaker which is in the next room, one of the new lights was already on (one has a bulb, the other does not), but when I flicked the switch (B) the breaker trips, switch A still worked fine.

So I guess I'm trying to figure out how to wire this new switch and light combo. In my eyes, this should be treated like adding a new lighting option as they are not connected to anything. Do I go from junction box to light and then to switch? Is it simply black to black and white to white in the junction box? I just made some wiring adjustments and what I have is switch A and switch B (sharing a switch box) acting like the up and downstairs switches. If I turn one on, the set of four lights goes on, and the set of two goes off. If I switch the other way, 4 lights go off and two lights go on. Obviously I have the power not connected right, but am unsure how else to do this.

That's what I was thinking sucosam, the 3 way is not part of this issue any further. You have a new switch and a new separate cable running to the switch. You cut the balck and attached each end of the black to the two screws on the switch, the white just runs through the box is not cut or connected to anything in the box. When the black and white reach the light they connect to the ligt fixture. black to black or blue and white to white

Trace back to the wires, the diagram below shows the two possible correct wire situations, one where the source starts at the switch box, the other where the source starts at a can. You keep saying junction box, but whether the connections take place in the can or junction box near the can it's no different.

http://i2.photobucket.com/albums/y3/...igurations.jpg

Bljack, I'm looking at the top half of your diagram and thinking this is how it's setup... at least the portion that's working which is the set of four pot lights. I've removed all wiring for the set of two pots, so that I'm starting anew here. Correct me if I'm wrong, but in this diagram, I should have the power source come in to switch A, which was a dimmer but has since been changed to a standard on/off switch because the dimmer is now broke.. won't go to off position. I should connect black from line source to one screw of switch A. Should I then connect black from wire that goes out to the fours pots to the other screw on this switch? As I type this, Switch A (formerly a dimmer switch) has black from power to one screw, and white from power to the other screw. All four lights work. If I want to add a new switch do I branch off black on switch A using a pig tail to switch B, and then on the open screw I connect the black from the wire that goes to the two new pot lights? Where does the white go?

Although I see the logic in the top half picture (black through the circuit and white back) to complete the circuit, the subtle change is that my one switch has a black connection and a white. Do I change this?

If power comes to the switch box, then the black wire from the source cable is connected to one screw of the switch, and then the black wire from the load cable feeding the lights goes out and connects to all the blacks of the lights.

The white remains neutral and gets tied to the load cable out to the lights with a wire nut.

To wire your second switch, you'd take two short lengths of black and cap them to the load cable. This gives two feeds, one for each switch.

The neutral for the other set of lights gets tied to the other 2 whites from the line and other load cable.

In that drawing above, ignore the "14/3" I was just copy and pasting the old drawing components for the new sketch and forgot to delete those. The switch loop wire is just 14/2, white remarked as hot to feed the switch from the source at the light and the black returning it to the junction box.

There is a source cable coming from the junction box into switch A, but this is the only cable coming into the switch box. The lights that this switch controls (the set of 4 pot lights) are linked into the circuit by getting a cable fed out of the same junction box. Can I still branch off this switch in this configuration? Or should I be adding this into the circuit some other way?

Quote:

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Originally Posted by ;

but this is the only cable coming into the switch box.

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Ding, Ding, Ding, we have a switch loop! Now it gets easy from here. For it not to be a switch loop, there would need to be 2 sets of wires coming into the switch box, so unless you removed a set of wires, the original configuration was a switch loop.

It goes like this...

The neutrals (whites) of the cable from the powersource cable and the cable out to the cans get tied together.

The blacks from the cable going to the switch and the cable out to the cans get tied together.

The black from the power source gets tied to the white from the switch cable. That white wire should be wrapped along the white length with black tape to show it's no longer a neutral and has been redesignated as a hot. That's why the white wire has black markings on it in the picture. This is what you should have to make it work:
http://i2.photobucket.com/albums/y3/...witchloop2.jpg

To add the new run of lights, you repeat the process, tie the white from the line to your new lights with the other neutrals.

Tie the white from your line to the new switch with the other white going to the switch box and the black from the powered cable.

Tie the black from the line from the new switch to the black from the line running over to the new lights.

The wire you ran to the switch box, well for each pair corresponds to one switch.

Tie in like this:

http://i2.photobucket.com/albums/y3/...DDEDSWITCH.jpg

The other way is to replace the existing run to the switch with 3 conductor. If your circuit is now using 14/2, you'd use 14/3, 12/2 use 12/3.

You'd still have 1 line going out to each string of lights and they'd all tie their neutrals together in the junction box with your power lead neutral.

The white from the switch line goes to the black from the power line, marking it with black tape.

Your 3 conductor switch loop wire has 2 return wires, a black and a red. Connect one to each light string and the other end to the particular switch you want to control that string.

In the switch box, you'd take 2 short lengths of black wire, tie it to the white with black markings to pigtail it so you would be able to connect it to both switches.

The volume of the box and size of the wire determines the maximum number of conductors allowed in the box. This reduces the number of conductors if other circuits also run through here and makes it less spaghetti-ish. The different color wires makes identification easier in my opinion.

http://i2.photobucket.com/albums/y3/...WITCHLOOP3.jpg

Bljack, thank you thank you for the information. I was able to get this working thanks in large part to your most recent diagram. I did have to connect the white from coming back from the cans to the white from a different power source (there are more than one in this junction box) as when I had it connected to the white from the other lights, the switches interferred with one another, but result is that it's working now. Thx to you and all others who offered their thoughts.

Sam

Bljack,

The electrical footprint for a switch loop would be at least two pairs of conductors, not one pair.

If there is only one pair, then the fixture is being powered by the switch.

Quote:

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Originally Posted by donf;

The electrical footprint for a switch loop would be at least two pairs of conductors

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I see that you are an electronics expert, so I'll go in the assumption that it's low voltage DC systems? Perhaps it's different there. In household wiring a switch loop is where the power is run to the device (light fixture, outlet, fan, etc) directly from the home run. Prior to connecting to the device, another 2 conductor or 3 conductor cable is run to a switch box. The white carries the current to the switch and the black and sometimes red carry it back to the device(s). By code, in the 2 or 3 conductor cable, the white must be the one connected to the hot to bring the current to the switch box where the switch will interrupt the circuit. Both ends of the white must be marked with black to indicate they have been reassigned as hot and not neutral. There will be NO neutral in the switch box, there isn't a need for one with a basic toggle or dimmer wires as a "switch loop."

Pulling power from an outlet with 2 conductor, hot and neutral, to a switch box, and running a second cable to a light, fan, switched outlet, etc, where you cap together the neutrals of the 2 cables and connect the hots to either screw of the switch will give you 2 pairs of wire in the box with the switch, will have a neutral in the box, but won't be a "switch loop"

Nope, you are wrong. However the reason you are wrong is because we are talking about opposite ends of the switch run.

My error, not yours. When I reread your response, I realized you were looking at the switch box. I was starting at the supply and loop connection.

I do apologize.

It's all good, Don. Enjoy the rest of your weekend :)