There are various ways to wire a switch, but one of the more daunting is 3 way switch wiring. This process, while harder than many basic wirings, is quite manageable to follow or figure out once you understand all of the different steps.

This guide will take an in-depth look into 3 way switch wiring to break down each part of the process and enable you to do your own at-home work in no time.

Why Use 3 Way Switches?

 Switches

For those new to electrical work, 3-way switches enable lights to be controlled from different locations. This is a popular method used in many homes, but older or simpler set-ups still exist.

Many people opt to change out such fixtures or upgrade their light switches themselves. While it is easy to assume that you need a professional for such a project, with the correct knowledge anyone can wire a light switch in just a few hours.

Though the process can be more complicated if you have to do drywall work as well, wiring a light switch without such obstacles is a process that anyone can handle.

Collecting The Proper Tools/Materials

As with any project, 3 way switch wiring require a set of specific tools. It is always important to make note of this beforehand so that you don't get too far into your work and then realize you're missing a key instrument.

Knowing and assembling what you need beforehand not only saves you time, it also creates a lot less frustration.

For this wiring style, you want a 4-in-1 screwdriver (the most versatile type), electrical tape, a utility knife, a non-contact voltage tester, a wire stripper/cutter, and needle nose pliers.

You should also gather up (or purchase) a 14-3 or 12-3 cable in addition to 3 way switches.

​Safety Always Comes First

man doing construction

Once you have everything ready to go, you can start with the wiring.

Setting up 3 way switch wiring is a process that happens in succinct steps. As long as you carefully go through each one you'll be done in no time.

The first thing you must do after assembling your tools is switch off the circuit. This may seem obvious to some, but for those not familiar with wires skipping or forgetting this step can end in disaster.

Electricity is harmful, and you must take the necessary safety precautions when wiring to ensure that you don't have an unfortunate accident.

First, locate your circuit breaker to turn off the switch. Though this is different from home to home, most buildings have the breakers in out-of-the-way places like the garage or basement.

Once you have located the breaker, find the one that controls the lights in the room you'll be working in and switch it off (just move the switch over).

From there, you should then take your voltage tester and double check that there is no power flowing through the room.

Even if your lights appear to be turned off, this is an important step that reduces the risk of fire or electrocution.

Get To Know Your Equipment

Next, you want to get familiar with your 3-way switches. This is a useful step that everyone, regardless of experience, should do in order to make the installation process much easier.

Looking at your switch, you want to correctly identify all of the terminals that you'll be connecting your wires to.

First, there are the traveler wire terminals. These sit on each side of the switch towards the top, which makes them easy to identify.

Then there is the ground wire terminal, which sits on the top or bottom of the switch and is mounted to the frame, and the common wire screw (located on the left side).

The common wire is easy to identify because it is a different color than both traveler terminals.

Add In Electrical Boxes

Electrical Boxes

Once you understand the switch or switches you plan to use, the next part of the wiring process is to install larger electrical boxes.

While you will already have a switch box in place, odds are it is not going to be big enough for your project. 3 way switches need a lot of extra wires to work, and that means they need extra room to properly operate.

Trying to cram in all of the additional wires into an old box simply won't work.

Rather, buy larger electrical boxes (which can be found online or at your local hardware store) and put them in where the old ones were. 

Feeding The Wires Through The Wall

After the boxes are in place and the switches are ready to go, you next need to work the wires through the wall.

First, pick your wire type. You need to either use a 14-3 type NM cable, or a 12-3 if you're connecting to 12-gauge wire. The breaker will affect this decision as well.

Once you've correctly identified your wires, feed the cables to the light.

If you already have a space for the wires to go you can follow that path.

However, if you do not have available space, or if you simply want to loop the wires somewhere else, you can do that by checking for studs, locating a free space behind the wall, cutting a small hole, and then slipping the wire through.

Just take note of any obstacles, such as drywall, fire blocks, or insulation, that you may need to overcome. Marking down such items will make everything run much more smoothly.

Putting It All Together

hands All Together

After the wires are where you need them to be, the next step is to link them up. A 14-3 cable has three insulated conductors that are respectively white, black, and red. It has a bare ground wire as well.

Use ground screws to connect those to their positions on the 3 way switch. If you are not familiar with this process, you can consult these diagrams to get an idea of what finished 3 way switch wiring should look like.

All of the switches are identified by a label on the common terminal. The terminal screw will also likely be a different color.

During this process, it is also important that you carefully wrap black electrical tape around the ends of white wires used as travelers between 3-way switches.

More Than One Method

more than one method

The above steps will cover most of your 3 way switch wiring needs. However, that is not the only way to convert a single-pole switch to a 3-way.

If you want to go another way you can.

To do this, the opening steps (getting ready and assembling tools) remains the same.

When it comes to the 3 way switch wiring, use a black wire in the top 2-wire conductor to attach the switch to the source.

From there, use pliers to turn the wire into a "J" and carefully wrap it around the black screw on the light switch (typically located at the bottom).

Once the wire is in place, you can carefully tighten the screw down to hold everything together. Cap the wires connecting the source and the switch.

Second Black Wire And Capping The Neutral

The second part of this method is to use the existing 2-wire conductor to connect another black wire from the light to the original switch location.

Once that's done, you should cap your different white neutral wires.

Put a plastic cap on the end of the white wire from the top conductor at the new switch. Then, cap the neutrals from the power source, light, and other end of the top conductor at the location of the original switch.

Travel Wires, Capping, And Switch Boxes

Wires

To continue with this conversion method, you next want to attach the traveler terminals on each switch by using the black and white cables from the bottom conductor.

As with the above processes, take your pliers and carefully bend the wires around each screw.

The final two steps from there are capping the grounding equipment at each switch (and the light) and replacing the switch box covers.

First, locate the grounding screw on each switch, wrap the wires tightly around them, and use your screwdriver to tighten everything down.

You then cap the conductors at each switch box, push the wires into the back of the box, and replace the covers.

Once everything is done and looks the way it should, screw the switches into the electrical boxes, secure the wall plates, and test your new lights.

New Lights In No Time

light bulb, pencils and eraser on top of paper

3 way switch wiring is an involved process, but it is not as bad as many people make it out to be. Each of the two methods above are more than doable with the proper planning, and they will give you great results.

Though you may not think you need new light switches, there is nothing wrong with upgrading. Not only will that make your life much easier in the long run, it truly doesn't take that much effort.

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