3-way switch issue

I have a light (upstairs) on 2 3-way switches and an unswitched light (downstairs). The home is very old (plaster walls) and I cannot tear- in. I would like to add the unswitched lamp to the switched circuit. I managed to run a line to the switchbox (and remove the original line in) but it doesn't work. here is the configuration currently:
Power in -> upstairs light -> Master Switch -> Slave Switch -> downstairs light
Is there a way to make this configuration work?
Thanks!
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jaezif wrote:

Probably, but...
To control from more than two places need two 3-ways and one 4-way switches. The configuration normally is to have the two 3-ways at the point nearest the source and the light and the four-way(s) in between.
Need to know number of wires you have between the points...
--
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The information you've provides is not sufficient to make that determination. The most reliable way to do it, is to run a pair of wires from the existing switched light, to the new, currently unswitched light. There may be another possibility, but it would be determined by where the feed to the circuit and the return wires to the light are located

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If you can run romex from the light fixture upstairs to the one downstairs it is easy to do.
Not real sure how you could do it from the switch box. Actually I am inclined to say you can't.
Colbyt
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Thank you for your responses. I cannot run wire from the upstairs light to the downstairs light bacause I do not have access to the upstairs light. I currently have 2 strand going to the upstars light and to the master switch, then 3 strand to the slave switch and 2 strand to the downstairs light... The upstairs light works as it should but the downstairs doesn't work at all.
Thanks,
Jeremy
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jaezif wrote: ...

Not enough conductors to the downstairs as a minimum to have all work in conjunction unless one side is coming from an unswitched hot.
Still can't follow the arrangement well enough to try to give a specific wiring diagram, but look up 4-way switches to see a typical installation of switching from more than two locations.
Otherwise, perhaps you can "ascii-art" a crude outline of the original circuit showing feed, lights and conductors between so folks could see what would be needed (or if can get there from here, of course).
--
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Or, make a sketch of what you have and scan it. Upload the sketch to tinypic.com and post the link here.
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Thank you for your responses. I cannot run wire from the upstairs light to the downstairs light bacause I do not have access to the upstairs light. I currently have 2 strand going to the upstars light and to the master switch, then 3 strand to the slave switch and 2 strand to the downstairs light... The upstairs light works as it should but the downstairs doesn't work at all.
Thanks,
Jeremy
If,what you just described, are all the conductors you have in the two switch boxes, it means that the feed is in the second floor lighting outlet and the only way to do it, is to go from light to light
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To make a linear arrangement like this work, you need the following number of conductors in each leg, in addition to the EGC:
Power in --(2)--> upstairs light --(3)--> first switch --(4)--> second switch --(2)--> downstairs light.
More expicitly:
Power in --> Upstairs light        Neutral, Hot Upstairs light --> First switch        Neutral, Hot, Switched Hot First Switch --> Second switch         Neutral, (2) Travelers, Switched Hot Second Switch --> Downstairs light    Neutral, Switched Hot
Yours, Wayne
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Nope, just 3.

Why does he need a "switched hot" in addition to the travelers?

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The upstairs light needs to be connected between the switched hot and the neutral. Thus the switched hot has to be taken from the second switch back to the upstairs light. It goes from the second switch, through the first switch box without being used there, and then to the upstairs light.
Another way to look at it is to suppose the upstairs light came last, after the downstairs light. Then you'd be carrying the neutral and the switched hot to the upstairs light. Now when the upstairs light comes earlier as it does here, you still need to carry the switched hot and the neutral to the upstairs light.
Yours, Wayne
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jaezif wrote:

If I understand you correctly the Power feed line goes to the upstairs light box. A single cable (2 wires) goes to the 1st switch from the light box. 3 wires go from 1st switch to 2nd switch. If this is the case then, this can work IF the old un-switched light can use its existing neutral (white). Hopefully the 2 lights were on the same breaker, but it will still work if not. Run a cable from un-switched light to the 2nd downstairs switch which you already did. Connect the hot for the downstairs light to the 'common' terminal on the switch along with the wire that is already there. You will need to 'pigtail' this. Cap off the unused white wire from the new cable in the 2nd switch box. Cap off the old hot line that was powering the un-switched light. As I said keep the old neutral wire on the light.
The above will also work if you have the power feed and light feed BOTH going to the 1st switch box. The key in both cases is the 2nd switch only has 3 wires.
If this does not work out then another option would be to use remote or wireless switch to activate the other light at the same time. Lookup X10 modules. Or a motion detector on the un-switched light may do the trick for you.
Kevin
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You do realize that your wiring scheme is illegal, hell, he could also use the bx cable as a neutral if he wants to do a real Rube

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Just to amplify RBM's comment, this is against the NEC and a bad idea. The net current in a cable should be zero, so the return path (neutral) has to be in the same cable as the hot. Otherwise you get alot of EMF, and if you have any metal boxes, you can get inductive heating of the metal boxes.
Yours, Wayne
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Wayne Whitney wrote:

Yes I understand the EMF and heating that can happen especially with wires in long metal conduit runs. The neutral will tend to cancel out. However in many switch legs, and especially with 3 & 4 way wiring, there frequently is no neutral wire running along with switch legs, travelers etc. This is almost always the case when the power feed is at the light fixture box. My guess is that the current supplying a light or 2 will not be a significant factor is most cases and almost zero using NMC (Romex) and plastic boxes. Kevin
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Even though a switch leg has no neutral, when properly wired the net current is still zero. For a simple switch leg, if the switch is on, the same amount of current is flowing to the switch on the "feed hot" as is returning from the switch on the "switched hot". For a 3-way leg, current will be flowing on one of the travelers and returning from on the "switched hot".
Cheers, Wayne
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