3 way switch help

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Old 01-07-18, 10:33 AM
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Question 3 way switch help

I have installed an occupancy sensor that is 3 way switch compatible. It's this one:

http://www.lutron.com/TechnicalDocum...ry/0301647.pdf

Please note: I have installed the same sensor in a different part of the house in the same manner, and it worked.

The issue I am having is the other switch (the actual toggle switch) does not control the light at all. So in other words, the sensor works fine (automatically or manually it controls the light) but the other switch doesnt do anything.

I have tried every single combination there is in both of them and it's not working. I obviously tried what the instructions manual suggests as well.

The way my switches were wired were like this:

Switch #1 (Sensor's switch):

1st screws: White - Black (Travelers)
2nd screw: Red

Switch #2 (Manual switch):

1st screws: White - Black (Travelers)
2nd screw: Red

What's the best way of diagnosing this?

I tried:

- Black/Red & White (results in lights being fully controlled by sensor)
- White/Red & Black (results in lights not working at all - so even sensor does not work)

I also disconnected everything and left all wires separate and I can see that White wire (in switch#2) has always power.
 
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Old 01-07-18, 10:41 AM
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When you work with a three way circuit and three way switches.... the important thing to keep in mind is what color or which wire is on the common terminal. The wire that comes off the common terminal gets connected to the new switch/device common.

Do you remember which two colors were the travelers ?
If you don't remember.... look at the cable in the box. The two traveler wires are always in the same cable.
 
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Old 01-07-18, 10:43 AM
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Originally Posted by PJmax View Post
When you work with a three way circuit and three way switches.... the important thing to keep in mind is what color or which wire is on the common terminal. The wire that comes off the common terminal gets connected to the new switch/device common.

Do you remember which two colors were the travelers ?
If you don't remember.... look at the cable in the box. The two traveler wires are always in the same cable.
Travelers were Black and White.
 
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Old 01-07-18, 10:48 AM
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Ok.... you know the travelers are black and white. That leaves one additional wire at each end which would be the common.
 
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Old 01-07-18, 11:02 AM
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Originally Posted by PJmax View Post
Ok.... you know the travelers are black and white. That leaves one additional wire at each end which would be the common.
Just to confirm, while in a single pole switch screw order wouldnt matter, in a 3 way switch, it does correct? So the hot wire will only be screwed on to the screw that doesnt have any adjacent screws.
 
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Old 01-07-18, 11:21 AM
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Screw location on a three way switch means nothing. Every manufacturer builds their switches differently. The only constant is the dark colored screw terminal which is common. The other two screws are travelers and there is no connection preference with them.

If there is no dark screw.... common may be stamped on the back.
 
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Old 01-07-18, 11:49 AM
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I see, well in my case the black wire in sensor location is live. That is all I know. How do I go from there?

So this is what I have done:

Shut off all power, removed everything and left all wires open, turned power back on, with a multimeter and a known ground, checked for 120V

The black wire in Location #1 is 120V. Rest of the cables are a bit strange (sometimes fluctuating up to 40V). Not sure if that bit is relevant.

When I connect the sensor and turn on the light. In the Location #2, white wire is 120V.

So I connect the white wire to the black screw and pigtail it with one of the travelers. And the remaining traveler goes to the other screw. Is that correct?
 
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Old 01-07-18, 12:22 PM
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Also the 3 way switches I have no colored screws or any letters or words on them to indicate which is common.
 
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Old 01-07-18, 12:56 PM
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Some very old three way switches were not labeled. You can use an ohmmeter to locate the common. The common will active in whichever switch position is selected.

You have the line (hot) at the sensor location and the load is at the regular switch end.
Travelers are black and white. Does that leave a red wire in that same cable ?
 
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Old 01-07-18, 01:45 PM
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This is very strange. I removed the old 3 way switch and used a regular newer 2 way switch. Everything works. With the old 3 way switch, nothing worked and I mean nothing, I tried all kinds of combinations.

What is wrong here? It's just the OCD in me who wont be satisfied with the ON/OFF label on the 2 way switch otherwise I would just leave it in there.

Can you also describe how I would use the Ohm meter to measure this? The sensor/location #1 is all good, the wire colors are all messed up and dont make sense. God knows if there is a junction box or something else going on somewhere.

What is strange and boggles my mind is the readings I am getting in location #2/manual switch whereby 2 of the cables are giving 40V reading against a known ground (and I tried various outlets, extensions, box, etc and I compared my values with a working GFCI, so I know my ground is good).
 
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Old 01-07-18, 02:09 PM
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That maestro control only requires a single pole switch at the slave end.

If you are using a digital meter...... induced or ghost voltages are very likely. When a dead wire is run parallel to a live wire..... since it is AC..... some voltage is magnetically coupled or induced onto the dead wire. Nothing harmful but just enough to make a sensitive meter see a random voltage.

We use voltage testers that have a built in load to eliminate those induced voltages.

If you connected a light bulb from that wire to ground. The light would not light up and your meter would now read 0v.
 
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Old 01-07-18, 02:15 PM
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Originally Posted by PJmax View Post
That maestro control only requires a single pole switch at the slave end.

If you are using a digital meter...... induced or ghost voltages are very likely. When a dead wire is run parallel to a live wire..... since it is AC..... some voltage is magnetically coupled or induced onto the dead wire. Nothing harmful but just enough to make a sensitive meter see a random voltage.

We use voltage testers that have a built in load to eliminate those induced voltages.

If you connected a light bulb from that wire to ground. The light would not light up and your meter would now read 0v.
I'll summarize my question/amazement/confusion regarding my current situation below :

- I have 2 wires connected to the a SP switch. Everything works. SP switch works like a 3 way switch with the sensor.

- I take the same 2 wires and connect to the 3 way switches 2 screws on the side (leaving the one on the other side without adjacent screws alone). it doesnt work. I swap the wires, it doesnt work again.

How is this possible?
 
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Old 01-07-18, 03:11 PM
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How is this possible?
Your 3-way switch can work like a plain switch, which is sounds like you already know. But you have to have one of the wires on the common screw or nothing will work. It doesn't sound like you used a meter to figure out the the common screw, but it you move one of the wires on the screws instead to that screw by itself on the other side of the switch, it'll work.

Now why you want to put the 3-way switch back in there, that part I'm confused about. Oh, just to get rid of the off/on markings I guess? I suppose I can understand that.
 
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Old 01-07-18, 04:40 PM
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I went to home depot and bought a brand new leviton 3 way switch. Wired it up exactly the same way. It works.

I have literally spent an entire day going crazy because of this stupid possibly 70 year old switch. It probably broke when I removed it, I have no explanation for it because I have the same one just like it in garage and I installed the same occupancy sensor there in the same manner.
 
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Old 01-07-18, 05:27 PM
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Wired it up exactly the same way.
How can you be sure you wired it up the same way, when you don't even know which screw was the common on the old one? I doubt the old one broke when you removed it. It's more likely you wired the new one the "same way" meaning the same physical screw locations. But as already has been pointed out, the locations of the screws mean nothing. On one brand of 3-way switch the common will be in position A, another brand may have it in position C, etc.
 
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Old 01-07-18, 05:49 PM
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Same way in a sense the same group of wires (jumper, traveler, and common in one screw, another traveler in other screw) were screwed in the same fashion, not in the same orientation.

the only thing I didnt do with the old switch was to try to connect to the single screw side. I left that side disconnected always and tried various combinations with the two other screws.

i know that side is not the common screw because i have the same switch in the garage working with the same sensor and same jumper wired way and that screw is disconnected.
 
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