How-To Install Single-Pole Electrical Switches

How-To Install Single-Pole Electrical Switches

In this tutorial we are going to divert from wood working to talk about it’s distant cousin, electricity and electrical switches. Why electricity? Well, because your beloved Porter Cable Random Orbital Sander doesn’t run off steam.

This is the first in a four part series focused on electrical switches. 

Whether you know it or not, there is a lot of electricity at work in your shop and sometimes your electrical system needs an update or add-on…

In every shop there are many applications for a variety of switches. For this reason it is important to know when and how to use them. You have switches that control electrical power to lights and maybe some receptacles. You also have switches that control electric motors.

Normal power switches are a little easier to figure out. They generally come rated for 15 amps or 20 amps. When you install a switch on a circuit, check the breaker for that circuit in the panel to see it’s amperage rating. Size your switch to match the breaker.

There are three types of switches: 

  1. Single-Pole
  2. Three-Way
  3. Four-Way

There’s no such thing as a double-pole or two-way switch. I don’t know why, that’s just the way it is.

Single-Pole Switches are pretty basic. We’ve all flipped one and many of us have installed them. But just in case you haven’t, I’m going to show you how.

First of all, what is a switch?

A switch is a non-load device, meaning it doesn’t consume power, which opens and closes an electrical circuit. A single-pole does this from one location.

So let’s wire up a single pole electrical switch.

In a single-pole switched circuit you have your power coming in, you have your light and in the middle you have your switch. Electricity travels in a loop. The black wire is the “hot”. That’s your incoming power. The white wire is your neutral and acts as a return path back to the panel. If either of these wires is disconnected or open, the circuit will not work. The switch always and only controls the hot wire. Never connect the neutral wire to a switch.

Switch Leg

So you have your hot and neutral coming into the box with the switch and you have a black and a white leaving your box and running to the light. Between the switch and the light, the black wire is referred to as a “Switch-Leg”. In some applications, the switch-leg will be colored purple instead of black. If it isn’t purple, it’s good practice to put a little curl in it so that in the future, you can distinguish between the incoming hot and the switch-leg. Which is really handy, believe me.

Make the Connection

So now that we know what our wires are, let’s make our connections.

But before we do, turn off the power!

Since we’re only controlling the hot with the switch, we’re going to connect the two neutrals together with a wire nut and stick it in the back of the box. We’re also going to attach all of the ground wires including a pigtail from the switch and stick them in the back of the box. Always use a pig-tail, never try to terminate two wires on the same screw.

That leaves us with our hot and our switch-leg. Which one goes to which screw? Believe it or not, it doesn’t matter.

When terminating the wires, it is recommend to bend small hooks on the ends of the wire then wrap that hook around the screw. This will hold a lot better than simply tightening the screw around the wires.

Also, as a safety precaution, it is good to wrap the whole thing with electrical tape a couple of times. So that completes the switch. When you screw it into place, make sure “On” and “Off” don’t read upside down.

Now on to the light.

Simply terminate the switch-leg to one screw and the neutral to the other. Easy as can be. And that’s your single-pole circuit and how-to install single-pole electrical switches.

Please feel free to leave any questions or comments below and please subscribe, like and share if you find them helpful!

I’ve got three more tutorials you can read and watch. Click on any of the following links (when they become available) to watch me size and install these other three types of switches: Three-Way, Four-Way, Motor-Rated

Single-Pole Switch Lighting

This is a single-pole switch controlling a single lighting fixture.

And remember! ALWAYS turn off the power before working on an electrical circuit!

Tutorial written by Scott Shaeffer of San Juan Carpentry

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