3-way switch confusion


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Old 02-26-17, 07:18 PM
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3-way switch confusion

My garage lights have a 3 way light switch setup with 3 light & 2 light switches. I have attached a diagram. I've used grey dashed lines to represent white wires. The first page shows the first electrical box (in the garage) which holds one of the 3-way light switches plus another 2-way switch for an outside light. The second page shows the other 3-way light switch (in the house). There are two other light switches in this box but they are not part of the same circuit.

The first part I am confused about is why the two way switch goes into a wire connector that also has a red and black wire from cable 2 & 3. I would have expected cable 4 to go straight to the 2 way switch. Why would the 2-way be involved in the circuit of the 3-way? What am I missing?

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Last edited by PJmax; 02-26-17 at 07:50 PM. Reason: added pics from link
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Old 02-26-17, 07:42 PM
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Welcome to the forums.

One important thing when working with three way switches..... one screw terminal is always the common. It's usually a darker color or black as compared to the other two traveler terminals.

I added the C terminal markings to your diagrams.

Cable 2 and cable 5 are the same cable.
The black and white wires are being used as the travelers.
The red wire in cable 2/5 supplies power to the three way switches. This is the line.
The red wire in cable 3 supplies the switched output to the lights. This is the load.
 
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Old 02-27-17, 10:27 AM
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Thanks for your reply.
So if I am following you correctly the black wire from cable 4 is supplying the power to:
- The 2-way switch (via the wire nut)
- The lights (via the wire nut & the black wire on cable 3)
- The 3-way in the house (via the wire nut and to cable 2/5 via the red wire)
Is that correct?
 
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Old 02-27-17, 11:26 AM
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the black wire from cable 4 is supplying the power to:
- The 2-way switch (via the wire nut)
Yes, but there is no such thing as a 2-way switch*. It is just a switch (SPST).

*2-way is used in the UK for what we call a 3-way but it has no meaning in the U.S.
 
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Old 02-27-17, 03:13 PM
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Thanks for the clarification on 3-way versus 2-way.

Do switches have to be next to doors for code purposes? The 3-way switch in the garage is next to a door which we never use. I'm looking to replace the switches with GE Z-Wave light switch (12722) & if I didn't need to have a switch in the garage I could save some money by removing the 3-way functionality & removing the requirement for the Add-on switch.
I would probably set the lights to come on by motion detection anyway. But for the sake of $20 I don't want to break a code that I'll potentially have to go back and fix at a later time. Hope that makes sense.
 
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Old 02-27-17, 04:36 PM
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Do switches have to be next to doors for code purposes?
Yes... for the most part. You shouldn't have to walk into a dark room.

The ad-on three way switch shouldn't be too much extra. I think it's like $12-14.
 

Last edited by PJmax; 02-27-17 at 05:08 PM.
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Old 03-12-17, 01:14 PM
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Finally getting around to replacing the switches with the GE smart light switch. Looks like the switch in the house should be the main GE light switch (12722) and the one in the garage should be the add-on.
I just wanted to double check something. The cable for the light switch in the house doesn't have a neutral, but I can just pig tail off another neutral in that switch box. Correct?
 
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Old 03-12-17, 01:58 PM
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can just pig tail off another neutral in that switch box. Correct?
Yes, if it is for the same circuit (breaker) as the light hot wire.
 
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Old 03-12-17, 02:06 PM
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Good point. Thanks for your reply.
 
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Old 03-12-17, 02:41 PM
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Actually that messes things up. I have one box in the house with 3 switches each on 3 different circuits. Garage, Outside lights, Back Door lights. The garage circuit only have one set of incoming wires without a neutral which is 2/5 in the attached. If I can't use the neutral from the Back Door light circuit then I'm stuck
 
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Old 03-12-17, 02:51 PM
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If you turn off one breaker does it kill the power to the 3 switches or do you need to turn off 3 breakers? If one breaker kills all three switches it is a single circuit.
 
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Old 03-12-17, 02:55 PM
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You need to look carefully at the wiring instructions. You HAVE to make changes at both ends.
You move the neutral to where you want it.

In your case.... your neutral is common to all the switches. Your wiring illustrates that.
 
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Old 03-12-17, 03:06 PM
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So I think the best answer may be to remove one of the switches in the circuit as I never use the one in the garage anyway. Then I can use the white cable in the house as a neutral and connect that to the neutral wire nut in the box in the garage. And then just connect the black wire in cable 2 to the red wire in cable 3.
 
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Old 03-12-17, 03:09 PM
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I need to turn off 3 breakers. One breaker for each of the lights connected to each of the switches.
 
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Old 03-12-17, 03:16 PM
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Hi. The common neutral in my diagram is common to the box in the garage. It's the box in the house I have the issue with. I'll update the diagram to show you what the box in the house looks like.
 
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Old 03-12-17, 03:31 PM
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In the first diagram..... the single switch is inside the house on it's own.
You want to put the WiFi switch in the house..... correct ?

That leaves the remote in the garage.

The box in the garage shows two switches yet you said it's controlled by three breakers ?!?!?!

Clarify exactly what you have and I'll give you a diagram to follow.
 
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Old 03-12-17, 03:50 PM
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After looking over what you have. Using that model of switch.... the master needs to be in the garage. The slave would go in the house.

The reason you can't just use any neutral(in the house) is that in your case since you are dealing with three circuits.... you don't know what leg of power each circuit is on. That means you must pull neutral from the garage box.

If you want to eliminate the garage switch.... then you can use the master by itself inside the house.

There are wifi switches that will operate on three wires. That would give you the ability of a main and a slave.
 
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Old 03-12-17, 04:37 PM
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Thanks for your help here.
The single switch which is inside the house is actually in a box with two other switches but because they are on different circuits I didn't include them in the wiring diagram. This is the box where I definitely want to have a switch. I will update the diagram.

I believe the power goes to the switch in the house first (via the red wire on cable 2) which is why I thought the master / primary should be in the house. With the lights off I have power going to the common on the switch in the house, but there is no power to the switch in the garage. Do I have this wrong?

Diagram to follow...
 
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Old 03-12-17, 05:00 PM
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You need four wires between the house switch and the garage switch to use that switch set.
You NEED..... line, load, traveler and neutral.
You have three.
 
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Old 03-12-17, 05:13 PM
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Agreed.
So I either need to buy a different switch or go with the wiring in the ProposedChange.pdf. Is that correct?
I have also attached a full wiring diagram as promised.
 
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Old 03-12-17, 05:25 PM
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I just realized I marked the add-on switches as primary and vice versa.. So ignore that for now.
 
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Old 03-12-17, 05:31 PM
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OK. Please ignore the last diagram and use this one (GarageLightsUpdatedv2)

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Old 03-12-17, 06:49 PM
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No more PDFs, please. Many people don't want to download unknown PDFs. Here is how to insert images in your posts. http://www.doityourself.com/forum/li...rt-images.html If you need more help doing images just ask.
 
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Old 03-12-17, 08:47 PM
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Ok will do that from now on. Thanks for letting me know.
 
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Old 03-12-17, 08:58 PM
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Is this the diagram you were trying to post?

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Old 03-13-17, 05:56 AM
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I've made the diagrams clearer and I'll re-post as inline images as requested
Here is the existing wiring. The first picture is of the box in the garage near the fuse box. The second the box in the house. As previously discussed the 3 light switches in the house are on 3 different breaker circuits:
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Here is the proposed update which would remove the switch in the garage and update the circuit to just have a single switch in the house.
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I really appreciate your help and your patience!
 
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Old 03-13-17, 10:30 AM
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Your wiring is correct and will work fine.

You could make one change. Reverse the red and black wires in cable 2 so that black to your new switch is hot and the red is the load.

If you don't swap the wires.... just remember red is hot and black is load.
 
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Old 03-13-17, 11:24 AM
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That's a good suggestion. I will do that.
Thank you!
 
 

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