Help with 3 way switch wiring...

I'm usually pretty handy and can fix about anything around the house but this one has me stumped. I decided to ask for help before I started just trying different combinations and causing a problem.

Looking to install a motion sensor light switch for the entry into the house from the garage. The light is on a 3 way switch with a switch at the bottom of the stairs (by garage door) and another switch at the top of the stairs. I can get it to work but only if the switch at the top of the stairs is in the up position. Obviously that's not right.

Here's the new light switch I plan to use. Legrand RRW600U http://pdf.lowes.com/installationguides/785007496574_install.pdf

This is a pic of the light switch at the bottom of the stairs where I want to install the motion sensor (downstairs switch). The black wire is connected to the common terminal with two traveler wires that are the same color (brown). I assume this is the "second" switch in the 3 way setup but don't know that for sure.



The ugly light fixture has two wires going to it. Black and white. I assume the black wire on the above switch is what's going to the black wire on the light but again not 100% on that.



Lastly this is the switch at the top of the stairs (upstairs switch). It is only about 5 feet from the panel (through a wall) so I assume it is the "first" switch in the 3 way setup. The yellow wire is connected to the common screw and again has 2 brown traveler wires attached to it.



Here's how the new switch calls to be wired. I want this switch to be installed in the downstairs location that has the black wire on the common and 2 brown traveler wires. I think that covers it but let let me know if more detail is needed.

http://pdf.lowes.com/installationguides/785007496574_install.pdf

Multilocation configuration (using existing companion 3-way switch): see Figure 5.
• Connect the green or non-insulated (copper) GROUND wire from the circuit to the green ground wire on the RRW600U. Make sure there is a solid ground connection.
• Connect the power wire from the circuit (HOT) to the black wire on the RRW600U.
• Connect the power wire to the lamp or fan (LOAD) to the red wire on the RRW600U.
• Connect one of the runner wires to the yellow wire of the RRW600U.
• For the companion switch, connect the chosen runner wire (presently hooked up to the yellow wire of the RRW600U) to the common of the 3-way companion mechanical switch.
• Connect one of the poles of the companion 3-way switch to ground.
• For the remaining pole of the companion 3-way switch, do not connect to anything, but still cap off with a wire nut.

Can I do this or do this switch need to be the "first" switch in the 3 way setup. If that's even a thing like I think it is.

Haha I just went through the opposite. I removed a motion sensor switch from a 3 way and put in a 3 way toggle switch. Ill be damned if I remember what I did though. I remember it took me 2 tries before it was wired right.
I've installed lights etc but I'm no electrician. My house was built in '55 and has all 1 color wiring, kind of like your downstairs setup.

The power will come in at one switch Location only. Which need to figure out.

There are colored screws on the 3 way switch

Basically the switch flips (inside) from the black screw (think of it as always used) and the 2 other screws usually gold. So only one is used in each switch position.

Probably best to unhook everything and find where the power starts and work your way through the problem. Then you can identify how to wire the motion sensor.

But yes you would need to wire it from "line" power only or in your case at the switch that's always powered.

You're on to the right track.



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You need one of those little beeper thingies. It's like a Sharpie sized piece that beeps when you touch it to a live wire. Maybe it's called a current tester? Not sure but it will make your life a lot easier when working on electrical around the house. You can even plug the tip into an outlet and listen for the beep until you find the right breaker.

Black screw (common) will be constant hot on one end and the common on the other end will be the switch leg to the fixture.

Like ccq8le said, best to start from scratch. Identify your constant hot and your switch leg to the light and the others will be your travellers.

Once you have that dialed then follow the instructions for the motion switch

ccq8le said:

The power will come in at one switch Location only. Which need to figure out.

There are colored screws on the 3 way switch

Basically the switch flips (inside) from the black screw (think of it as always used) and the 2 other screws usually gold. So only one is used in each switch position.

Probably best to unhook everything and find where the power starts and work your way through the problem. Then you can identify how to wire the motion sensor.

But yes you would need to wire it from "line" power only or in your case at the switch that's always powered.

You're on to the right track.



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Click to expand...

I'm 99% sure the upstairs switch is the line in power. It's closest to the fuse box, the wire doesn't match the wire in the fixture and would explain why I could only get it work with that switch in the up position. I will verify that though and not just assume.

98 svt said:

You need one of those little beeper thingies. It's like a Sharpie sized piece that beeps when you touch it to a live wire. Maybe it's called a current tester? Not sure but it will make your life a lot easier when working on electrical around the house. You can even plug the tip into an outlet and listen for the beep until you find the right breaker.

Click to expand...

I have one and a multi-meter. So think I'm covered. Bought the chicken stick (not sure that's it real name) over the summer when I had to replace the capacitor on my home AC. Wanted to be 100% sure I had no power running to it before I messed around.

This one to be exact
Dual Range Non-Contact Voltage Tester with Flashlight, 12 - 1000V AC - NCVT3P | Klein Tools - For Professionals since 1857

blk02edge said:

Black screw (common) will be constant hot on one end and the common on the other end will be the switch leg to the fixture.

Like ccq8le said, best to start from scratch. Identify your constant hot and your switch leg to the light and the others will be your travellers.

Once you have that dialed then follow the instructions for the motion switch

Click to expand...

I'm more confident with DC than I am with AC. But lets assume the upstairs switch is the constant hot (yellow wire) and downstairs is the switch leg (black wire). These are the instructions from the new motion switch.

Multilocation configuration (using existing companion 3-way switch): see Figure 5.
• Connect the green or non-insulated (copper) GROUND wire from the circuit to the green ground wire on the RRW600U. Make sure there is a solid ground connection.
• Connect the power wire from the circuit (HOT) to the black wire on the RRW600U. This would be my yellow from the upstairs switch?
• Connect the power wire to the lamp or fan (LOAD) to the red wire on the RRW600U. This is where I get lost. Is this not the black wire on my downstairs switch? Do I use one the runner wire not being used below to connect this to the red wire on the upstairs switch?
• Connect one of the runner wires to the yellow wire of the RRW600U.
I just pick one of the two runners and hook it to the yellow.
• For the companion switch, connect the chosen runner wire (presently hooked up to the yellow wire of the RRW600U) to the common of the 3-way companion mechanical switch. The runner I picked for above would go the common on the downstairs switch?
• Connect one of the poles of the companion 3-way switch to ground.
This would just be taking a length of wire, hooking one of the runner wire screws on the switch downstairs to the box? There's not grounding wire since conduit is required here.
• For the remaining pole of the companion 3-way switch, do not connect to anything, but still cap off with a wire nut. I should cap off the wire on both sides for the runner wire I didn't use? Assuming I don't use it for the load like I asked above.

Thanks for the help guys. I'm probably making this harder than it needs to be but don't wanna mess it up.

Here's a pic of the diagram from the instructions if it helps.

^yea that schematic makes no sense for a conventional 3 way scenario.

blk02edge said:

^yea that schematic makes no sense for a conventional 3 way scenario.

Click to expand...

Yeah man, it's odd. The more that I think about it I think I'm going to use one of the spare travelers to run the always hot to the box I want it in. Then in that box I'll have the always hot, load and I can use the remaining traveler to go back to the companion switch. But I'm not confident enough to say that would work and was hoping someone could confirm it should!

RX1Cobra said:

Yeah man, it's odd. The more that I think about it I think I'm going to use one of the spare travelers to run the always hot to the box I want it in. Then in that box I'll have the always hot, load and I can use the remaining traveler to go back to the companion switch. But I'm not confident enough to say that would work and was hoping someone could confirm it should!

Click to expand...

Ok I did some more reading and turns out you are good to go, certainly not a conventional method but times and products are changing! (This one is new to me)

Anyway, you are correct, get the switch leg and constant hot to the sensor and then at the existing switch you are just switching the yellow to ground. Makes sense now

blk02edge said:

Ok I did some more reading and turns out you are good to go, certainly not a conventional method but times and products are changing! (This one is new to me)

Anyway, you are correct, get the switch leg and constant hot to the sensor and then at the existing switch you are just switching the yellow to ground. Makes sense now

Click to expand...

Funny enough I found someone with my exact problem in the Amazon reviews. He ran it like I said and it worked. So going to give it a shot.

Amazon Reviewer said:

I need to call tech support for my wiring configuration. I was placing the senor in the location where there was NO HOT wire directly from the breaker box. In the Sensor location, I had a 14/2 (used for the light) Black and a 14/3 traveler wires (Black & Red), the White wires from the 14/2 and 14/3 were wire nutted together. In the Mechanical switch location I had 14/2 and 14/3 wires. The HOT was the 14/2 (directly from the breaker box) Black and a 14/3 traveler wires (Black & Red), the White wires from the 14/2 and 14/3 were wire nutted together.

So here is what I did:

Connect the green or non-insulated (copper) GROUND wire from the circuit to the green ground wire on the RRW600U. Make sure there is a solid ground connection.

Connect the power wire to the light or fan (LOAD) to the red wire on the RRW600U.

Connect one of the runner (traveler) wires to the black wire of the RRW600U. (NOTE: this will end up being the hot wire when connections are made in your mechanical switch location.)

Connect one of the runner (traveler) wires to the yellow wire of the RRW600U.(NOTE: this will be connected to the common terminal of your mechanical switch in your mechanical switch location.)

*** The following steps are done in the mechanical 3-way switch location ****

Disconnect the Mechanical 3-way switch.

Connect the ground wire. Make sure there is a solid ground connection

Connect the runner (traveler) wire (presently hooked up to the yellow wire of the RRW600U) to the common of the 3-way companion mechanical 3-way switch. (The common terminal will be the darker brass connection).

Connect one of the mechanical 3-way switch traveler terminals (old traveler) connection to ground. Make sure there is a solid ground connection.

Using a wire nut, connect HOT wire (the wire from the fuse box / breaker box) to the runner (traveler) wire that goes to the black wire of the RRW600U.

For the remaining pole of the mechanical 3-way switch, do not connect to anything, (if a wire lead and not a terminal, just cap off with a wire nut.

Click to expand...

Right on, well good luck and let us know how it works out

Worked perfect but glad I checked the wires first. I thought upstairs was the live and downstairs was the load. I had them backwards. But still used the same plan and used one of the travelers to run the switch wire downstairs and it works perfect.

Thanks for the help guys.

There’s about a dozen ways I can wire a 3 way. Do you have a meter?




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Try adding a 4 way to the mix......

In my early 20's I worked for an electrical supplier and the Electricians used to come in to pick up orders and such. I used to do some side work with one of them that I got to be pretty good friends with. (He mostly installed sub panels and hot tubs and such) so I learned a lot about power and single phase, 3 phase etc.

Anyhow they all would tell me the most lucrative $$$ to them was people who goofed up 3 way switches or switched outlets in bedrooms.

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coposrv said:

There’s about a dozen ways I can wire a 3 way. Do you have a meter?

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Click to expand...

I do. Got it figured out though. The whole motion sensor deal is what threw me off. Apparently the companion 3 way switch no longer has power running to it. It really just grounds a signal back to the motion sensor to turn the light on or off manually.

ccq8le said:

Try adding a 4 way to the mix......

In my early 20's I worked for an electrical supplier and the Electricians used to come in to pick up orders and such. I used to do some side work with one of them that I got to be pretty good friends with. (He mostly installed sub panels and hot tubs and such) so I learned a lot about power and single phase, 3 phase etc.

Anyhow they all would tell me the most lucrative $$$ to them was people who goofed up 3 way switches or switched outlets in bedrooms.

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Click to expand...

I could see that. It takes a bit to figure out how to do it right but once you got it takes 2 mins to swap them out.

Not that anyone really cares but I got the smart 3 way dimmer installed with no issues. Have pretty much every light in the house now on either smart switches or plugs. Waiting for Google to start turning my lights off if I say something they don't like!