You are all tucked in on the bed, nice and comfortable. Then you remember that the light is turned on! Now you have to go across the room to switch it off. Annoying right?
That’s where a 3-way switch comes in handy.
What’s the process of wiring a 3-way switch?
I can wire a 3-way switch in 3 ways. In method 1, the power will be going to the switches first, then the light fixture. In the second method, power will be going to the fixture first. And, in the last one, the fixture will be in the middle of the switches. 2 different types of wire will be used.
I am going to explain all the methods step by step. Just keep reading!
Item Needed for Wiring a 3-Way Switch
Here are some tools I am gonna need to wire a 3-way switch:
- #2 Phillips end screwdriver
- led voltage detector (for testing the electric wires. To make sure there is no power running on the cable while working)
- 15 amp, 3-way switches (these come with 2 terminals and grounds)
- wire strippers
- 1 gang new work electrical box (j-box)
- 1 gang old work electrical box (j-box)
- 1 gang old work depth adjustable (j-box)
- nail plate wire shield
- Long nose pliers
- 3/4” spade bit (6”, 16”)
- 1/2” cable staples
- cable puller (fish tape)
- 14/2 cable 2 wire w/ ground (50, 250 feet)
- 14/3 cable 3 wire w/ ground (100, 250 feet)
Here, I am using a 15 amp switch and for powering, a 15 amp breaker. That’s why these cables are suitable. I wouldn’t use these wires if I had a 20 amp breaker.
This is a 3-way switch common mistake everyone makes. Because they are gonna overheat.
In that case, I need 12/2 wiring, because they are thicker than the 14 gauges.
Also, I am going to need two more amazing products. I bought it from here:
3 Methods for Wiring a 3-Way Switch
There are three methods by which I can wire a 3-way switch. All are very simple. I am going through all the processes thoroughly.
Method 1: Switch, Switch, Power Fixture
In this method, power goes to both of the switches first, then to the light fixture. Here’s how I have done it.
Step 1: Before inserting switches onto the j-box, I am going to do something first. I always attach the ground pigtail first. I am going to take two 14/2 pigtails, as I am using a 14 gauge cable.
I am going to make a loop on each pigtail with the Voltclaw wire puller. It has a small hole for this job. You can also use needle nose pliers. But I find it more convenient.
I am taking the 3-way switch. And then attaching the loop with the ground terminal in a clockwise position. And I am tightening it in a clockwise position. Doing the same for both switches.
Step 2: I am taking the 14/2 power supply. And I am inserting the wire into the first j box for 6-8 inches.
Step 3: I am taking the hot (black) wire to make a loop. I am using my wire puller for this.
Step 4: I am taking the first 3-way switch. Then I am gonna take the hot wire from the power source. And hook it onto the common terminal, which is the black screw. I am gonna tighten it down and keep it like this for now.
Step 5: I am taking a 14/3 wire with ground and feeding it into each j-box. Now, I am back to the first j-box. I make sure to keep one group of wires separated from the other group. I am gonna strip the wires of the 14/3 cable with a plier.
Step 6: I am gonna loop only the red and black wire. And then I take the switch and hook the black wire onto the right traveler terminal. Screwing them tightly.
Step 7: I am taking the red wire and putting it onto the left terminal. Screwing it tight. You can choose the right terminal for red wire too. But in that case, the second switch also has to connect in the same way.
Step 8: I am gonna use the Wago wire connectors to connect the grounds. Opening the lever of the connector, connect the ground wires together. Doing the same for the neutral wires. I make sure no exposed copper of the wires is outside the connector box.
Step 9: I am moving on to the 2nd 3-way switch. Here the 14/3 cable is already fed. I am looping the red and black wires.
Step 10: I am gonna take the second switch. And connect the red and black wire with the switch terminals. I have to make sure to mirror the first switch so the terminals are matched.
Step 11: I am taking the 14/2 wire, and feeding it onto the j-box from the light fixture.
Step 12: I have one common terminal left, the black screw. I am attaching the 14/2 cable’s black wire to it and tightening it nicely.
Step 13: I am gonna take all the ground wires, and connect them with a 3-way wire connector. I am taking another 2-way connector and connecting the neutral wires together.
Step 14: Come to the light fixture now. I am connecting the ground wires with the wire connector. Taking the black wire, matching it with the other black one connecting them. Doing the same with neutrals.
And it’s done! If you don’t have an electric outlet for 3-way light switches, install one. Adding an electric outlet anywhere by yourself is actually easier than you think.
Method 2: Light Fixture, Switch, Switch
In this method, the power supply is going to the light fixture first. Then it’s going to the switches. That’s how I connected using this method.
Step 1: Same as the first method, I make the switches ready with ground pigtails. Taking a 14/2 cable and feeding it to the light fixture j box.
Step 2: I am gonna take the 14/3 wire. And connect the light fixture and j box 1 with it.
Step 3: I am connecting the 3 ground wires from 14/3, 14/2, and light cables. I am again using the wire connector. Doing the same with white wires.
Step 4: I am gonna take the hot wire from the power source. And I am connecting it with the red wire from the 14/3 cable. Taking the hot wire from the fixture, and connecting it with the 14/3 black cable.
Step 5: I am gonna move on to the first switch j box. I am only gonna loop the hot wire. taking the 3-way switch, attach the hot wire to the common terminal.
Step 6: I am gonna connect the ground wires of both with a connector. But I am taking a three-way connector. Because another ground wire will come here.
Step 7: I am taking another 14/3 cable and feeding it to the first j box. Another end of this cable will go to the 2nd j box.
Step 8: Coming to the 1st j box again, striping the wires. I am gonna take the ground wire and feed it to the other 2 ground wires.
Step 9: I am looping the black and red wires. I am gonna take the 1st switch. Attaching the red and black wires with two terminals. Screwing them tight.
Again, you can mix and match what wire goes to which terminal. But I have to do the same with the 2nd switch.
Step 10: The white wire from the 14/3 cable is going to turn into the hot wire. So, I am marking it with black electrical tape.
Step 11: I am taking the red wire which is going to the fixture. And connect it with the new hot wire together. Clipping the white wire coming from the light fixture alone.
Step 12: Moving to the last box. I am gonna strip the wires from the 14/3 cable. Also, I am marking the white wire with black tape. As it is going to be the hot wire now. I am gonna loop all three wires.
Step 13: Coming to the 2nd light switch. I have to mirror the first switch to connect the red and black wires. I am connecting the ground wires together.
That’s it! One more thing! If you have a problematic outlet, the switch may not work. You can replace the electrical outlet box by yourself.
Method 3: Switch, Light Fixture, Switch
In this method, the light fixture will be in the middle of two light switches. The power source will be with the first switch box. Here’s how I do it.
Step 1: I am feeding the 14/2 wire with the first light switch j-box. And I am gonna loop the black hot wire. And connect the hot wire with the common terminal of the light switch.
Step 2: I am using a 3-way wire connector with the ground wire. And leave it like that for now.
Step 3: Now, I am feeding the 12/3 cable into the j-box. The other head of this will go to the light fixture. Taking the ground wire of it and connecting it with the other one.
Step 4: I am looping the black and red wires. attaching on the switch terminals. I am gonna connect the two neutral wires with a connector.
Step 5: Skipping the light fixture for last, I am moving onto the 2nd j-box. I am gonna feed a 14/3 cable here. The other head will go to the light fixture.
Step 6: I am gonna loop all the wires. Taking the red one, and attaching it to the switch terminal. Here is an important thing I am gonna do. I am not putting the black one on the 2nd terminal. Instead, I am putting it on the common one.
Step 7: The neutral wire will be re-coded for the hot wire. I am gonna level it with black tape. And then attach it to the 2nd terminal.
Step 8: I am gonna connect the ground wires of the switch and 14/3 cable together.
Step 9: Moving on to the light fixture. First, I am gonna feed all the wires to the fixture j-box. I am keeping the wires apart so I don’t get confused later.
Step 10: I am connecting the ground wires from the 1st, and 2nd wires. And also from the light fixture. All together with a 3-way connecting wire. Also, gonna combined the red wires and connect them,
Step 11: Here’s another tricky part. I am gonna connect the black wire of the fixture now. But only with the black wire coming from the 2nd switch. The light fixture’s neutral wire will only be connected to the first light switch.
Step 12: I am now only left with the neutral wire from the 2nd light switch. And also the hot wire from the 1st light switch. Here, I am recording the neutral one with black tape. That indicates this is now the hot wire. I am connecting these two wires together.
With that, the 3-way light switch is connected. Sometimes your outlets and switches can be crooked. Fix those crooked switches and outlets to avoid accidents.
Do I Need a Special Light Switch for a 3-Way Switch?
Yes, 3-way light switches are different from the regular switch lights. 3-way light switches have an extra terminal which is called the common terminal. It is needed to connect both switches to each other.
Is the Common Wire On A 3-Way Switch Always Hot?
Yes, it is normal for the common wire to be always hoy. Unless the breaker is off. The common wire is also called the hot wire. It carries the electricity from the power source.
What Happens If a 3-Way Switch Is Wired Wrong?
If the 3-way switch is connected wrong, one of the switches may not work. Both switches may also not work. Sometimes connecting the wires wrong can lead to short-circuiting.
Wiring a 3-way switch may look difficult at first. But If you follow the steps attentively, I hope you can easily do the job. Always remember to be careful while working with the electric wires and consult a professional.
Before touching the hot wire of the power supply, check it with the voltage detector. This habit can save you from many mishaps.