Wiring a 2-Way Switch





How to wire a 2 way switch. Wiring a 2-way switch is about as simple as it gets when it comes to basic house wiring. First of all we need to go over a little terminology so you know exactly what is being discussed.

Go to my Switch Terminology Page where I discuss the terms used for the different types of home electrical switches. It should also help in understanding the functions of each type of switch.

When wiring a 2-way switch circuit, all your really doing is controlling the power flow (Switching off/on) to the load (a light, lamp, outlet, ceiling fan etc..).

Now a typical circuit will contain a 3-wire cable known as romex. The cable consist of a black wire, a white wire and a bare copper wire.

Black wire = Power or Hot wire
White wire = Neutral
Bare copper = Ground

When wiring a 2-way switch circuit, all we want to do is to control the black wire (hot wire) to turn on and off the load. This simple diagram below will give you a better understanding of what this circuit is accomplishing.

2-way Switch Wiring Diagram

Now in the diagram above, The power source is coming in from the left. Notice the black wire is the only wire that we are controlling through the 2-way switch. You have an incoming hot wire (black) going to one screw (it does not matter if you use the brass or silver screw) on the side of the 2-way switch and a black wire from the other screw on the 2-way switch going to the load (light, ceiling fan etc..). The white wires are wire nutted together so they can continue the circuit.



Basic 2-way Switch Wiring Diagram



Now as for the ground wire. It is very important to connect the ground wire to the switch as well. The Green screw on the 2-way switch is for the ground so all ground wires should be connected as seen below.

2-way Switch Ground Connection diagram

All ground wires (bare copper) are all now connected (incoming ground, load ground and switch ground). This makes for a safe protected circuit by having all grounds intact.

So what have we accomplished. By wiring a 2-way switch, The circuit below shows the basic concept of electricity flow to the load. Let's assume the load you are controlling is a light. The electricity flows from the hot wire (black) through the 2-way switch (shown in off position) and then to the light and returns through the neutral wire (white). This is a completed circuit.

2-way switch electricity flow diagram

Now by understanding the diagram above, go up to the top diagram and by using the concept shown here, just use your mouse pointer on that diagram and follow the flow from black wire (hot wire) to the load and return through the white wire (neutral). This should give you a good basic understanding how the 2-way switch circuit works and will help you in adding or changing a 2-way switch.

So now that you have a basic concept of wiring a 2-way switch, let's look at the following 2-way switch diagrams to see which type of circuit scenario you have. After you have pulled your switch out from the wall, the wires in the box and connecting to the switch should look like one of the following.

Basic 2-Way Circuit - Power Coming In At Switch

Basic 2-way Switch Wiring Diagram




Basic 2-Way Circuit - Power Coming In At Light

Power at Light 2-way Switch Wiring Diagram




Power Coming In At Switch - With 2 Lights In Series

2 lights with 2-way Switch Wiring Diagram




Power Coming In At Light - With 2 2-Way Switches and 2 Lights

2-way Switch with Lights Wiring Diagram




Power Coming In At Light - With 2-Way Switch and Outlet

Light and Outlet 2-way Switch Wiring Diagram




Power Coming In At Switch/Outlet - With Light

Light with Outlet 2-way Switch Wiring Diagram





Allow Tim Carter from AskTheBuilder.com to show you some great tips for installation and wiring a 2-way switch.