The things no one tells you:
I’ve decided to take a quick break from our regular series: living in a smart home. This week I’m going to go over something that many people have asked about but also something I’ve worked on myself and had many questions during the installation: 3-Way Switches. I feel as though most home’s have more of these style of switches but that may only be due to the fact that most switches you either want to automate or control are 3-way as they’re typically in entry points of rooms and most rooms have multiple entry points. To preface, this isn’t necessarily an ultimate how-to guide but I will be explaining it along the way as best as possible. Ideally: YOU SHOULD BE READING THIS BEFORE YOU BUY. However, if you’re like me you didn’t bother searching for it until after you’ve bought them, you might be okay. So, strap in and hold on cause this one’s gonna be a long one.
This is only an amateur’s guide. I am not a professional electrician, simply a DIY enthusiast as many who read this are. Importantly, we’re working with a major shock hazard in your home. Please be sure to turn off circuits appropriately. However, I cannot gauruntee your safety and I do not how your home is wired. If you are unsure how or do not feel comfortable working on electricity I highly recommend you contact a licensed electrician to install your switches. If you continue reading and performing the installation, you would be doing so at your own risk and I cannot be held liable. Also, I recommend doing a regular switch BEFORE tackling 3-ways so you know what to expect. Utimately, you should contact a local professional for questions about proper code and wiring.
The Bad Kinda 3-way:
Now that we’ve tackled some of the legal stuff and the introduction, let’s get to learning. Once again, I highly encourage you to read this BEFORE you purchase switches, but I’ll give some pointers if it’s too late.
Okay, cool… so what do you need to do first then?
Aside from you working with electricity and the dangers, the first thing no one tells you is to not buy your switches right away. The reason I explained in my last article still stands and that is that you should do your research first. Not only to find the best switch to fit your budget needs but more importantly which electrical connections are available. So, let’s go over your first steps:
- Turn ON the lights in the room and take note of which switch it is, especially in 4-way gang boxes. Also, locate the other switch that controls the same circuit and note of it as well. (Speaking from experience, I spent 3 hours installing and troubleshooting the wrong switch. I know it sounds dumb but when the power is off you cannot test this. Get a clear piece of tape and just mark under the switch.)
- While the lights are ON locate your home’s circuit panel and cut the appropriate breaker OFF. The reason I do it like this is when you go back to the room, the lights should be OFF. This way you know you have the right breaker. DO NOT RELY ON THE MAPPING NEXT TO THE BREAKER.
- With a screwdriver (typically a flat-head.) Remove both covers of the light switch(es).
- Many smart switches require a COMMON (aka Neutral) wire. They are generally white (but may not be) and there are generally a whole bunch of them connected together (or there may not be). If your switches are like mine BOTH SWITCHES will REQUIRE this connection.
Typically a “remote” switch in my home does not have the common wire. While it’s not the end of the world this may prohibit or alter your purchasing decision. Head back to google and try to find some smart switches that do not require the common wire. Do some research. I cannot recommend any products as I haven’t used them and do not feel comfortable telling you so. In my case, I use GE Z-wave Smart Switches. These switches require that common wire. There are some out there that do not. However, I found many of them sacrificed something. So, see what works for you.
- There will also need to be “Traveler” wires that come off of your remote switch. Typically they are red but once again, they may not be.
- You’ll also need to locate which switch has the power coming from this box. That is where you’ll put your primary switch. You can guess but be prepared for headaches. I recommend buying an inexpensive multimeter from your local home store to identify which one is hot. (More on this later)
- After you’ve done all that, replace everything and flip the breaker back on. Go online and buy your switches. For the GE Switches, you’ll need two. You’ll need the main switch that is their normal smart switch such as a GE On/Off Switch and also an add-on switch. These are what I use and can honestly recommend. The work natively with SmartThings and have some cool options.
Okay Dave, I think I’ve got everything and ordered up my switches. Now what?
If you prefer videos, I highly recommend watching Jasco’s tutorials on YouTube just to get an idea of what you’re doing first. REMEMBER that they’ve minimal wiring in their boxes and they have it setup perfectly. Real-life isn’t perfect. My house had many different colored wires, so we’ll go over what mine had. Also, it’s important to look up other videos that simply explain how 3-way switches work. I personally prefer a more simple diagram since the lights are already installed:
Here we see the HOT (aka Line) coming into the switch. From there, the circuit is designed so that no matter how your switches are toggled, they will complete or break the circuit. The reason I like this diagram is it also clearly demonstrates how the Neutral isn’t in the loop on the switches and are connected to the bulbs. Sadly, if your switches are like mine they will look like a rat’s nest.
Alright! Think I got it. Switches came in today, ready to install?
Yup! Hopefully, you have all the necessary connections (I’ll show what happens when you don’t) so let’s go through an installation. I’ll have a mix of photos since I’ve already installed all 3-Way’s necessary in my home but I’m adding the main switch to my bedroom. (The “main” switches are wired similarly except for traveler.) I’ll show you some of the add-ons as well. Since I enjoy nice ordered instructions:
- Once again, if they’re not already there. Re-label which switch you’re working on. It just helps.
- Cut the power from the breaker as before with the light on. This will help re-assure that you’ve got the power to the lights cut off. Remove the cover plate, then remove the switch.
- TAKE A PICTURE OF THE SWITCH. (It’ll help in case you have to abandon everything)
- Label the wires. Go ahead and grab either some white electrical tape or normal scotch tape will work. Wrap a piece around each wire and with a sharpie note which screws they’re attached to. (I label them: Top Left (TL), Top Right (TR), Bottom Left (BL), and Bottom Right (BR). Leave some space cause as we identify them we’ll note what they ACTUALLY are.
- Remove all wires and spread them out, now yell at everyone in the house to be careful and don’t go near them. Turn the power back on. Return to the wires, placing your Black lead on the multimeter on the GROUND wire (usually bare-wire OR green) touch your Red lead on the Bottom-Right wire, if you get a voltage reading of 120 AC volts that’s your Hot or Line, if there’s nothing, move to the other wires till you find it. It will go to the LINE plugin on your new switch. Go back and cut the power back off. Label your Line wire.
- Typically the other black wire above it will be your LOAD. You should also have a Red wire that is your TRAVELER. If you have either two Blacks or two Reds, you’re going to have to find out which is which. There are several ways to accomplish but really as in the diagram earlier, it doesn’t ultimately matter. (Once again, there are SEVERAL ways to do 3-ways. This is why when you go on Reddit everyone stays clear of giving advice because it’s a mixed bag. In the diagram above I actually have two travelers and the load is going to the lights off the auxiliary switch. So in my case, color doesn’t matter as long as it’s the same wires. To check this, wire-nut both wires together (not the LINE) and return to the aux switch. Using a continuity test (looks like a Christmas tree on your multimeter) test the 3 wires in different pairs. You’ll see OL (Open Line) when there’s no circuit and you’ll see lights and/or a small ready when you’ve found the travelers. Add to your labels (on the aux switch) T1 and T2. The other remaining cable is your LOAD to your lights, label it so.
- Here’s where things get interesting. Now disconnect those two wires on the main. Connect the LINE wire to ONE of the wires and wire nut them together. Restore power. On the AUX side use your multimeter on AC Voltage, then put your black lead on the ground then your Red lead on T1. If there are 110-120volts, guess what? That’s now your new LOAD/LINE. If it’s on T2, that’s your new LOAD/LINE. (I’m using that phrase because the non-LINE wire on the MAIN switch will go into your LOAD port on the Smart Switch then it will become HOT when it has power. Speaking of power, go turn that off at the circuit breaker. So on the AUX side, take that wire (T1 or T2) and wire nut it directly to the LOAD. (Yes, that’s right it will not go into your add-on switch.) The remaining wire is your traveler. Add-on switches only have two connections. Traveler and Neutral. Finish wiring them as appropriately on the add-on side and main side. Traveler to Traveler
- BEFORE YOU THINK YOU’RE DONE:
- Connect the Bare/Green wire to the Ground on your smart-switch.
- Restore power and test to see if the switches are working BEFORE SCREWING THEM IN. I cannot tell you how infuriating it is to assume you’ve got it but you don’t. Once again, speaking from experience.
- Cut power and screw ONE switch in, test again. Also, experience speaking, sometimes you jog a cable lose especially when wiring the neutral in the wire nuts with 4 other wires.
- Do the final switch, yeah you got it. Test again.
- Now put the plates on.
Here’s a new MS-Paint rough diagram of what we’ve got going on now:
The reason this works is because the Add-On switch has NOTHING to do with the lightbulb. Inside these switches are relays. Power is always going to them. When you work the Main Switch you tell the relay to connect/disconnect the circuit internally as opposed to the switches mechanical movement to complete circuits. The Add-On switch has a traveler line that is sending/receive a signal to the main to tell the Main Switch to turn off or on.
Whoa dude, that was a lot. Mine doesn’t look like that at all…
As I said earlier, 3-way switches are the bad kind of three ways. I’m going to apologize in advance that I cannot help everyone. Depending on the age of your house, if the builder was cutting corners, or they’re 100% up to current code you could see many different things and different wiring diagrams. My suggestion is as before:
- If you don’t feel comfortable or don’t have necessary tools. Hire a pro.
- Take pictures and label everything BEFORE you disconnect. It helps if you give up to be able to put it back as it was. (I still have a switch outside that I can’t get to work right cause I’m dumb and didn’t think about all this.)
- Colors are never standard. While Electric Code is law, codes changes over time and rules have changed over the years. So, in your case think of Pirates of the Caribbean. “They are not really rules as much as guidelines that natural way of things.”
- Speaking of code, if you wire something incorrectly or against code, you’ll have to fix it before you sell your home. You also knew about it and should be disclosed. So once again, look up your local code and try to make everything right. If it’s not right, call a pro.
- When it doubt, Hire it out! It’s not worth it.
Got it, but let’s say I already bought the switches and didn’t notice I was missing a common.
As I said earlier, things should be done according to code. However, I made this mistake as well. Here’s how to get around it when you Add-On specifically doesn’t have neutral. Again, back to my awesome MS-Paint Diagrams:
What I did was bypass the first switch and turned my Remote switch into the Main Switch. However, like a crappy Chess move:
- You will either have a BLANK switch port
- Or if you leave the existing switch there as a dummy, it does nothing. This confuses people especially guests and significant others.
- Disrupts natural “flows”, by flows I mean when entering/exiting a room the light needs to be there. In my case, this works because the original room was a garage and it never made sense to between with.
Here’s the layout of the room which I got with doing this. Once again, I don’t recommend doing this but if you must and cause no one else told you:
In my family room, the Line goes into the original gang box then the travelers goto the other switch. However, the original gang box was inside the hallway, not in the room. So, when you wanted to get up to turn the lights on/off when watching tv, you had to go outside the room. So, you’d naturally go to the switch that’s inside room. When you come in from the Outside, I wanted the lights to automatically come on when the door is opened hence the automation portion but the light switch is still available there.
The only interruption to my original flow was coming in from the hallway. Bring in my Amazon Dot. While it’s annoying it’s not very often we need to turn the light on/off via that hallway switch (my wife didn’t ever do it from there either.) so after linking the switch through Alexa you can turn the room on/off or set the dim level from the comfy couch. This is the only reason it works with my family room. However, in rooms like my kitchen, I wouldn’t do this as you’re simply “passing through” most of the time to transition through the house and yelling at Alexa isn’t 100% guaranteed to work. I also can put a motion sensor in the hallway to have it automatically turn the lights on if entering but that requires some more advanced automation.
Okay… but what if…
As of right now, this article is 2,500 words. We had a lot to cover but I can’t cover everything. I’m SURE you’re going to have a lot of What-Ifs in this scenario. While I’ll do my best to help you I’m once again not a professional. Simply a DIY enthusiast. If you do have any questions I highly recommend going on Reddit.com/HomeAutomation and posting the question there. There’s TONS of helpful people (and a lot of know-it-alls be they good or bad) that can assist.
Also, I’m sure in writing this I made some mistakes, this document will be a “living guide” that I’ll update over time as people give me their input so feel free to leave any constructive criticism and I’ll do my best to keep it as relevant as possible.
Thanks for reading! Good Luck and See you Next time!