Electrical Made Easy | How to Hook Up a 3 Way Switch in 2017

how to hook up a 3 way switch

When you decide to create a smart home on your own, you’ve signed up for some major DIY work. It may seem overwhelming at times, dealing with smart devices like a wifi thermostat, a smart home hub, sensors, lights, and of course light switches. However, installing smart home devices or learning how to hook up a 3 way switch doesn’t have to be such a headache.

With a little research, you can become a home automation DIY expert and even install simple electrical equipment.

Electrical work can be the most intimidating for a DIY homeowner, but you really can rewire your home with smart devices and not electrocute yourself! It’s possible, I promise! In fact, I wired my whole home myself with no prior experience and I didn't get shocked even once. 🙂

One of the most intimidating installations (whether Z-Wave or not) can be wiring a switch so that you get the right result when you trigger (or flip) it. But don’t worry! In this article, we'll show you just how to hook up a 3 way switch - one of the hardest switches to do yourself.

What do 3 way switches do?

You may be asking yourself, "Why do I even need a three way switch?" or "Why do I need to know how to hook up a 3 way switch when I can just hook up regular switches?"

A 3 way switch works like this: If you need to control one device (such as a light) with two switches, such as one switch on the north side of a room and one switch on the south side, then you need to wire a 3 way switch.

For example, you might want to be able to turn your main living room light on or off from beside your front door and also from the hallway to the bedrooms. Using two on/off switches with one light is the most common scenario, so we’ll use this example for the rest of the article.

Can’t I just connect two regular light switches to each other?

Unfortunately, you can’t because you need a switch with three terminals. While a normal switch has two terminals (the “on” and the “off” positions), the three-way switch has three, obviously, which is the two normal “on” and “off” terminals, plus a third for connecting to the other switch or the device. Basically, you need all three items (Light, 3-Way Switch 1, and 3-Way Switch 2) to connect together.

How should I connect my 3 way switch?

You can configure it in different ways, but you’re basically creating a circuit with the device (here, a light) and two switches in any configuration. This means you can have the wire go from the fuse box to the light and then the two switches, or to the switches and then the light, or you can have the light in between the two switches on the circuit. It doesn’t matter how you have them lined up, as long as you have all three on the same wire.

How to Wire a 3 Way Switch

You have two options for wiring a 3 way switch: running the power through the switches to the light or from the light to the switches. In both options, we’ll have four colors of wire, and you need to understand their different uses before we move on.

  • Black - This is a HOT wire, meaning that power is running through this wire. Make sure your fuse is turned off while wiring this kind of wire!
  • White - This is a neutral wire paired with the black. If it carries a current, we recommend you put black electrical tape on it to indicate it’s hot.
  • Red - This is a switch wire or traveller wire, used to carry current inside the switch.
  • Green or Bare - This is a ground wire that grounds the entire current.

Quick Note

Not all switches are installed with the correct colored wires, so the above colors may be different than what you have in your home. To ensure your safety, make sure you test the wires prior to attaching them to your switch with a voltage tester. Also, always turn the main power off before installing a switch!

Option One

Three way switch with the power going through a switch

With this configuration, the power flows from the fuse box, through Switch 1, to Switch 2, and finally to the light fixture.

The black and white wires follow this path, as does the ground wire. The red traveller wire is connected to the third terminal on both switches and runs between them only, not to the fuse box or the light. The black wire (the one with the power) is connected to both switches at the COM terminal or common terminal, which is usually black or copper colored. Both the black and white wires end at the light.

Using a short piece of wire and a connector, you want to connect the ground wire at every junction but the light fixture; it needs to attach to the switch itself and also to the box.

Option Two

Three way switch with the power going through the light

Z-Wave 3 Way Switch Wiring Diagram

Z-Wave 3 Way Switch Wiring Diagram

When the power flows from the light fixture, things get a little bit more complicated. This is because the white wire has to carry the power, so you should cover it in black electrical tape to show that it is hot; this ensures that nobody coming in after you hurts themselves while making repairs.

When the power comes through the light first, you need to splice them at the light fixture so they run through it and then to Switch 1. When you get to Switch 1, attach the black wire to one terminal and the black-taped white wire to the other.

Then, attach the green ground wire to the switch and the box, and attach the red wire to the third terminal. Splice the green, black and black-taped white wires to run them to Switch 2, where you connect them the same way. The red wire then goes with the other three to connect both switches.

The Z-Wave Variant

You may be wondering, "How do I hook up a Z-Wave 3 way switch?" After all, this is Z-Wave Zone, right? How could we not mention 3 way Z-Wave switches? Well, don't worry, here we'll show  you how to hook up a Z-Wave 3 way switch.

Wiring ​a Z-Wave 3 way switch is virtually the exact same as wiring a standard Z-Wave switch. The only difference is that some Z-Wave 3 way switches don't require a traveller wire, which actually makes the install a tad bit easier, however, others do, which makes installing them exactly the same as standard 3 way switches.

GE 45613 Three-Way Switches

​The GE 45613 3 way switches install exactly like standard 3 way switches, so you can either follow the directions mentioned above or watch the video. Either way, the directions are the same.

Linear WT00Z 3 Way Switches

Linear's 3 way Z-Wave switches do not require a traveller wire, so if you do not have one, its okay. In fact, if you have 3 way lighting set up in your house and you don't want it anymore, you can program one of the Linear switches to control a different Z-Wave device rather than the original light it controlled.

The two switches you need are the ​Linear WD500Z-1 and the Linear WT00Z-1. The former is a standard Z-Wave switch and the latter is the slave unit that can be used to control either the 3 way light or a separate Z-Wave device.

Conclusion

You may have thought that you could never learn how to wire a 3 way switch, but it’s easy if you use your electrical knowledge and follow this article. In no time, you’ll have the convenience of two switches for your lights or any other electrical device you want in your smart home!

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