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-   -   3-way light with a twist (http://www.diychatroom.com/f18/3-way-light-twist-71407/)

Jeepsail 05-17-2010 01:10 PM

3-way light with a twist
 
First I want to admit that I did the wrong thing. I should have maked the wires before disconnecting them...:whistling2: That being said, I need some help recreating what appears to be an unusual 3-way light switch/circuit.

The light is in the middle. Power comes in from a switch. Power leaves from the light, heads to run another room.

I moved the switch where the power comes in and replaced the 3-wire that ran between it and the light.

I disconnected the light entirely (to run the fish tape).

Where can I find a wiring diagram to show me how this needs to be re-wired?

Following the basics I can get the 3-way to work. However, there's no power running to the family room now.

HooKooDooKu 05-17-2010 01:27 PM

Depending upon the situation, you might need a meter and do some detective work.

For starter, how many wires are we talking about. After all, if there are only three loose wires (excluding ground, that ones obvious) that were originally connected to a three way switch, then the only thing that should be important it to get the correct wire originally connected to the "common" terminal on the old switch connected to the "common" terminal on the new switch (and the other two then shouldn't matter). If so, then you just have to identify the "common" terminal on the new 3-way (the ones I've seen, it's the dark colored terminal where as the two travelers are a different color), then just trial-n-error with a different wire connected to the common with each trial should solve the problem.

secutanudu 05-17-2010 01:47 PM

This may help:

http://www.homeimprovementweb.com/in...s/wiring3l.gif

Jeepsail 05-17-2010 02:47 PM

HooKooDooKu,

Power comes in on a 2-wire (black, white, ground), is connected to the light on 3-wire (black, white, red, ground), the power that exists the lamp is a 2-wire (black, white, ground), and the wire that leads to the other switch is 3-wire (black, white, red, ground).

Its the basic set of wires for a basic 3-way. I just can't figure out how "clean"/non-switched power leave the ceiling box that the light is in.

Jeepsail 05-17-2010 02:53 PM

secutanudu,

Thats a great figure, but I don't see where the power leaves the light to power another room.

I suspect that only one of the travelers is hot at a time. So maybe in the ceiling box I take the white from the switch and pigtail into the "exiting" power's white wire and then take the white/black tape from the other switch and pigtail it to the exiting black?

jbfan 05-17-2010 03:39 PM

You need another wire to carry the constant hot to the other room.
I would run another hot, neutral and ground from the switch location to the other room.

HooKooDooKu 05-17-2010 03:48 PM

How many wires are at the lamp, 2 or 4.

And while we're at it, lets try to find a way to simplify this...

First of all, a light is typically provided electricity in on of two ways:

1. Switch - Black/White constant power goes to a switch box. In the switch box, the black goes through the switch. The switched black hot and the white neutral then go to the light to supply switched power.

2. Switch Loop - Black/White constant power goes to the light box. The white power is connected to the white for the light. But the black power is connected to a white that goes to a switch. The black coming back from the switch is then connected to black for the light. When a switch loop is done this way, the white between the light and switch is actually now a constant hot and is supposed to have a black piece of tape wrapped around it to remark it from a neutral to a hot.

Not a three way switch is typically wired up the same general way (power to the switch, switch power to the light... OR power to the light, with a switch loop for the hot). The difference is that rather than just one switch, there are two switches that are connected together via travelers (the NON-Common screw terminals). Three wires are used to connect the two three way switches together, two for the two travellers, and one for the additional wire. So if you think of two three-way switches as a single unit, externally, you simply have two terminals for your hot to run through (these are the two common terminals, one on each 3-way) and internally, you have two wires that connect the two travelers, plus a third wire to account for the fact the two parts of the switch are in two boxes.

So with a 3-way, you can set it up as a switched hot or a switch loop.

If it's a switched hot, then your constant hot goes to one common terminal, the black and red of your 14/3 connect the two travellers together, the white of your 14/3 is the netrual you've got to get from one box to the other, and at the far end, you connect 14/2 from the switch to the light with the black of the 14/2 connected to the common on the switch, and the white connected to the white of the 14/3.

If it's a switch loop, then you send constant power to the light, run 14/2 to the 1st switch just like you would for a singe switch loop (white is constant hot, black is return switched hot). You still connect the two 3-ways together with 14/3. Two wires connect the two travelers together, and the third wire connectes to the common terminal on the far side. So back at the 1st switch, you connect the two wires from your light to the common terminal of the switch and the other to the third wire from the common at the far side of the switch. Now this part I'm not sure about, but I THINK the standard for running the 14/3 between the two switches is to either connect the white of the 14/3 to the hot white of the 14/2 from the light, then use the black and red as the travelers between the two switches... OR connect the hot white to the common of the switch, use the red and white of the 14/3 between the travelers, and the black of the 14/3 from the far side common back to the black to the light.

With any of these setups, anywhere you have a constant hot AND a neutral, you can pigtail off of that to go to the next outlet. keep in mind that even though white wires are used in switch loops, because they are being used as a hot, you can not pigtail off of wires that are in the middle of a switch loop... because a switch loop (by definision) is a constant hot wire to the switch and a switched hot comming back.


NOTE: The picture Secutanudu provided is something of a cross between simple switching and a switch loop. It's not totally a switch loop because you don't send the hot to the light 1st. But it's also not completely a simple switch as the neutral doesn't come with the switched hot. Notice how the netrual from the original power source goes only to the light bulb in the 1st half of the 14/3, but the 2nd half of the 14/3 is like a switch loop.

AllanJ 05-17-2010 03:59 PM

Did it used to work, or are you adding something new?

If you can see the various cables (or groupings) of wires coming into the box, making a note of what is in each cable will help a lot.

Power from a 3 way switch up to a light in the middle needs 4 conductors to provide 3 way action and also send a constant power feed on from the light to something else.

Jeepsail 05-17-2010 07:53 PM

AllanJ,

Yes it worked before.

In the ceiling box there are three wire cables: One 2-wire (12/2), and two 3-wire (12/3).

In one of the switch boxes there are two wire cables: One 2-wire (12/2) and one 3-wire (12/3).

In the other switch box, there is one, 3-wire (12/3) cable.

Every reference I've read says the same thing: that I need a 4-wire conductor to transmit power. However, I still have the original switch box with the 2-wire and 3-wire cables.

HooKooDooKu - I'll need to digest what you've written...

The house was originally wired in the 1960's. if that helps any.

AllanJ 05-17-2010 08:57 PM

1 Attachment(s)
Unless something illegal was done way back when, like using the ground wire as the neutral coming up from the switch with power. Giving you the 4 conductors. So everything worked way back then.

Now that you took it apart and then put it back together correctly, you discovered that there are not enough wires to make everything work.

What follows does work.

Sparky8370 05-17-2010 09:29 PM

Quote:

Originally Posted by AllanJ (Post 443296)
Unless something illegal was done way back when, like using the ground wire as the neutral coming up from the switch with power. Giving you the 4 conductors. So everything worked way back then.

Now that you took it apart and then put it back together correctly, you discovered that there are not enough wires to make everything work.

What follows does work.

That diagram wouldn't work anyway.
sw1 up, sw2 up = two hot legs (same circuit) at light, no difference of potential

sw1 dn, sw2 up = light will come on

sw1 dn, sw2 dn = two neutrals (same cicuit) at light

sw1 up, sw2 dn = light will come on

Sparky8370 05-17-2010 09:35 PM

With what you have, there are a few possible scenarios. Assuming the information you have provided is accurate.
The first thing you need to do, is disconnect all the wires from each other and cap off. Take notes as to what was where, and if it was already there or if it was something you did.
Make sure the power is off before you start. Turn it back on and identify the feed. Mark each wire and where it goes to. Something does not sound right.

Or call an electrician.

McSteve 05-17-2010 10:11 PM

I'd just about bet, based on the wires you say you have in each box, that it was originally wired up the way AllanJ's diagram shows. I believe this is called a "California 3-way" or "farmer's 3-way". Unfortunately you can't legally wire it back up that way.

The problem with that arrangement is that depending on the switch positions, the light socket shell might be hot instead of the center contact, posing a potential shock hazard. Or, in another switch position, the shell and center contact could both be hot. The bulb would be off, as there would be no difference in potential, and yet there would be power to the socket, posing a shock hazard.

Sparky8370 05-17-2010 11:00 PM

Quote:

Originally Posted by McSteve (Post 443361)
I'd just about bet, based on the wires you say you have in each box, that it was originally wired up the way AllanJ's diagram shows. I believe this is called a "California 3-way" or "farmer's 3-way". Unfortunately you can't legally wire it back up that way.

The problem with that arrangement is that depending on the switch positions, the light socket shell might be hot instead of the center contact, posing a potential shock hazard. Or, in another switch position, the shell and center contact could both be hot. The bulb would be off, as there would be no difference in potential, and yet there would be power to the socket, posing a shock hazard.

Well if AllanJ's diagram was a California 3 way, that would explain all the wild fires. :laughing:

Actually, what you are talking about (California or dead end 3 way) is perfectly acceptable, it's just not as you describe.
To put it in the simplest possible terms, the point on one switch gets the constant and the point on the other gets the load. The other two screws on each switch get connected with travelers between the two switches. There are many numbers of ways to do this. In each example, if there is to be a feed to another portion of the circuit it will be tied together with the feed. For clarity, I will only mention the feed.

Feed at light
In this example there would be a feed at the light box. There would be a 3 wire down to each switch location.
Both white conductors in the 3 wire cables will be remarked or taped black.
3 wire to switch A-light box end
Black- wirenutted to constant hot
Red- wirenutted to other 3 wire red
white-
wirenutted to other 3 wire white

3 wire to switch A-switch end
Black- point (different colored screw)
Red- traveler (usually brass colored screw)
white-
traveler (usually brass colored screw)

3 wire to switch B-light box end
Black- light load
Red- wirenutted to other 3 wire red
white-
wirenutted to other 3 wire white

3 wire to switch B-switch end
Black- point (different colored screw)
Red- traveler (usually brass colored screw)
white-
traveler (usually brass colored screw)

Feed at switch
In this example (the easiest) there would be a 2 wire feed at one switch location, a 2 wire load at other switch location, and a 3 wire between locations.
Feed switch location
2 wire cable
Black-
point (different colored screw)
White- wirenutted to 3 wire white

3 wire cable
Black-
traveler (usually brass colored screw)
Red-
traveler (usually brass colored screw)
White- As noted, wirenutted to 2 wire white.

Load switch location
2 wire cable
Black-
point (different colored screw)
White- wirenutted to 3 wire white

3 wire cable
Black-
traveler (usually brass colored screw)
Red-
traveler (usually brass colored screw)
White- As noted, wirenutted to 2 wire white.

There are other ways to do it as well, but these are the two most common.

HooKooDooKu 05-18-2010 01:24 AM

Quote:

Originally Posted by Jeepsail (Post 443263)
HooKooDooKu - I'll need to digest what you've written...

Here's pictures to go along with my descriptions:

http://www.homeimprovementweb.com/in...s/wiring1l.gif
Simple 3 way switch

http://www.homeimprovementweb.com/in...s/wiring2l.gif3 way switch loop... power goes to the light first, and then the hot goes through the switch loop.


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