3 way Smart Switch Wiring: A 5 Steps Guide

Electrical switches have been our companion since the age of Edison. With time we have seen small changes in switches. Switches became more and more safe and stylish.

And as more time passed by, people wanted to interact less and less with daily appliances. As a result, we started seeing, sound responsive switches. These switches turned on and off in response to loud sounds.

But this too started to become inefficient to people. So, people brought in 3 way smart switches. These switches just don’t turn on and off lights. These switches can dim your lights to the exact percentage on command.

However, it’s not easy to do a 3 way smart switch wiring on your own. To do this, you’ll need every cut and corner of the wiring process.

No worries. We’re here to make everything easy for you. In this guide here, we will discuss the whole process from the very scratch.

So, let’s not waste any more time and jump right into the details-

Step 1: Switch Location

The effectiveness of your 3 way smart switch installation depends a lot upon your switch location. So, how does a 3-way switch work?

Well, simply put, a 3-way switch setup connects and controls one light fixture. See it like this- you have two switches on two ends of a hallway. Both switches can control one appliance.

Now back to the locating stuff. Make sure that your chosen location is at a convenient location. Possibly at chest height. Also, suitable locations are in hallways, bedrooms, etc. However, this is only applicable if you want to create a new switch in your home.

If you want to replace your old switch with a new one then you can skip this part.

Step 2: Tool Collection

Now that you have your location set, you can focus on gathering up some necessary items.

So, we have classified the necessary items into 3 categories.

At first, we have must needed items. Here you’ll need-

  • Philips head Screwdrivers
  • Flathead Screwdrivers
  • Pen Voltage Tester

Next, we need moderately important items. The list-

  • Wire Nuts
  • Wire Stripper or Lineman Pliers
  • Electrical Tape

Lastly, we have the Multimeter.  This item will help you in a great deal while installing the smart switch.

Step 3: Wiring Approach

Now it’s time to get at that wiring chore. But before that turn off that breaker on your main electrical panel. But there’s a way around the switching off whole-house method.

If you know the circuit board like the back of your hand, then go and just turn down the circuit for the switch you’re working on.

Now let’s get back to our switch. Unscrew your switch plate screws and remove the plate.

Now you cannot think of replacing the smart switch without approaching the wire, right?

So, once you’ve successfully removed the switch plate, gently pull out the switch out of the electrical box. Be extra careful so that no wire dislodges from the switch terminals.

Now look at the wires and see if all the wires connected have different colors. If not then, mark those wires with tapes or markers. After marking all the wires, take a snapshot of the whole setting.

You can do this every time you make major changes with the setting. This will help you reassemble the whole thing.

By the way, we have a short note for you. Till now we have described everything from the perspective of one switch. But in reality, you have to do everything for two switches individually.

Step 4: Wiring Situation Assessment

After opening up we believe that you have a pretty nice view inside each box. Now we will go deeper.

Inside each electrical box, you’ll see two bundles of wires. For better understanding, we’ll call one Box A and other Box B.

Also, we’ll assume that your switch is on the ground floor and not in the basement.

Now, let’s look at the actions of both boxes individually-

Box A

In this box, the wires should enter from the bottom. These wires come in a bundle. There’s a 97% probability that you’ll find two colored wires and one bare copper wire.

You’ll see another 4 wire bundle entering from the top of the box. This bundle will have a red, a black, a white and bare copper wire. These wires do al the connection between two switches.

Box B

Here too we have two bundles of wires. But the entrance direction isn’t the same here. But the wire combination is the same in here. One 3 wire bundle and one  4 wire bundle. The three wired one connects the light appliance to your switch. 

Step 5: Swapping the New Switches

We believe that you’ve collected a good 3 way smart switch by now. So, it’s time that we started off the real work.

But before that draw up a 3 way smart switch wiring diagram and see if it matches our description from the previous point. If it doesn’t then call on an electrician.

Now let’s start.

In box A, untangle the 3 wire bundle. Take the black wire and attach it to the black painted panel on your new switch. If you can’t recognize the panel by color, then see if it’s labeled as COM.

 After doing that, open up the 4 wire bundle. Pick the red and black wires from that bundle. Attach these two wires on the two brass switch terminals.

Inside box B, do the same thing with the 3 wire bundle black wire. In short repeat the steps from box A.

Lastly, attach the bare copper wires with the green terminals of your switches. Attach the white wire with the neutral port of the 3 way smart switch. Once, you’re done with connecting the wires, push these back into the electrical boxes. Screw the flawlessly.


Once you’ve turned on the power you’ll have your 3 way smart switch wired. Now you’ll be able to avail of some extra benefits.

I am very much enthusiastic about Home Automation and actively developing open-source software to extend its capabilities so this is going to all be biased by my own experiences.

We will be happy to hear your thoughts

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