How To Wire A Single Pole Switch
Originally contributed by James Ferry
James grew up working on a cattle ranch in Northern Utah, which taught him how to do many ad hoc repairs and to make use of limited materials. Two years of missionary and humanitarian work in the Philippines with Operation Smile instilled a great appreciation for the opportunity to work, to avoid wasting resources, and to help others. Now back in the U.S., James has worked as a programmer/data engineer for several Fortune 100 companies.
You’re flipping your light switch on and off, but nothing’s happening. You’ve changed the lightbulb, you’ve tried asking it politely to turn on, but still, nothing but crushing darkness. Okay, maybe that’s a bit of an exaggeration. Nevertheless, it’s annoying.
Or maybe you’re giving your home a facelift and want to swap out your older-style toggle light switches for rocker ones. I mean, come on, “rocker.” Even the name sounds cooler!
We understand that electrical repairs can be intimidating, but so long as you’re careful and follow our guide, this is a DIY project we’re confident we can handle together. We’ll teach you not only how to safely wire and install a single pole switch with three wires, but how to do it free from any doubts. So without further ado, it’s time to make the switch, switch!
What You'll Need
- Utility Knife
- Voltage Detector
- Wire Cutter (As Needed)
- Wire Stripper (As Needed)
- Needle-nose Pliers (As Needed)
- Wall Plate
- Single Pole Light Switch
Turn Off Electricity
After the inspirational DIY spark hits, it’s easy for the air to become electric with excitement. It can make us want to jump right into things once we’ve purchased our new switch(es). But before we start taking things apart, the electricity to the existing switch needs to be cut off by flipping the appropriate breaker switch on your breaker box.
The breaker box should have the area you intend on installing your single pole switch labeled on the panel.
Remove Wall Plates
Now that the power’s off and it’s safe to start working on the switch without having your hair stand up on end, it’s time to remove the switch cover plate. Start by removing the two screws that hold the switch cover to the wall.
Protect Your Paint
If the wall cover plate does not come off easily, it’s because these switch covers can become stuck to the paint on your walls.
To prevent stripping the paint off the wall’s exposed area, use a utility knife to carefully cut around the outside of the switch cover until it comes loose.
Test For Electricity
We want to be confident that the power is off. To double-check whether or not there is still power going to the switch, use a voltage detector to determine if the electricity is indeed turned off.
Simply place the detector inside the switch box and test the wires on both sides of the switch by touching them with the voltage detector. If there is still an electrical current, the detector will light up or start to beep.
If the voltage detector starts beeping or flashing, go back to the breaker box and investigate whether the correct breaker switch has been turned off. Repeat this process until you have turned off the appropriate breaker and the voltage detector verifies that no power is going to the switch box.
Remove Old Switch
To wire a new single pole switch, you have to remove the old one. Makes sense, right? To do this, remove the screws from the top and bottom of the switch.
The old single pole wall switch can stick to the paint on the wall, just like the switch cover plate. To reduce the risk of stripping the paint, use your utility knife to cut along the top and bottom of the switch before removing it to minimize any potential paint damage.
Access Old Switch
Gently pull the switch away from the wall. Keep in mind there will be wires attached to it, so don’t pull it out too much to avoid damaging the wires. Pull the switch away from the wall so there is enough space to access the wiring.
If it looks like there are extra wires in the switch box, they are there in case the switch needs to be transferred to a three-way switch system. Three-way switches are used to control a light or fixture from two separate locations.
As we are installing a single pole switch, use only the three already connected wires, and don’t worry about these extra wires in the switch box. Just ensure the extra wires are closed with a wire cap, let them be, and move on.
Tip: Put a folded sticky note on the wall underneath the switch box to catch any dust or drywall that may fall when you remove the switch to save some time on cleanup.
Remove Ground Wire
There are three wires on a single pole light switch: two electrical wires (often black) on one side of the switch, and an exposed copper ground wire attached to the other side, sometimes coated in green.
Ground wires are used as a safety precaution to prevent electrical shocks when the switch’s electricity is on. They do exactly as their name suggests. They keep us grounded.
Info: Grounding gives excess electrical charges a safe place to go. To ground electricity means to give it the most effective and safest route from an appliance or outlet back to the ground below our feet, which has a negative electrical charge. This is achieved through the ground wire. This way, excess electricity from, say, faulty wiring, is safely dispersed throughout the home, rather than potentially giving someone a “shock” via a light switch, wire, outlet, or appliance.
You can also tell which one is the ground wire because it is attached to a green screw on the single pole light switch. Loosen this green screw with a screwdriver and detach the ground wire.
Remove Electrical Wires
To remove the two electrical wires, repeat the same process on the other side of the single pole light switch. Loosen the screws with a screwdriver, and disconnect the wires.
Keep track of which wire was on the top of the switch and which was on the bottom. To remember which is which, bend the top wire up and the bottom one down.
Tip: If the electrical wires are closed so tightly around the screw that you can’t pull them off, use a flathead screwdriver to open the wire by giving the screwdriver a quarter turn until the wire loosens around the screw and can be removed.
Wire The New Single Pole Switch
Now that the old switch is removed, it’s time to install the new one. Realign the new switch’s electrical wires by wrapping them around the screws, just like how they were on the old switch.
Many switches state “Top” or “Up” on the metal switch bracket. Some switches include “On” or “Off” on the switch toggle (if it has one), so you can orient the switch by ensuring these words are written right-side-up. If these markings aren’t on your switch, don’t worry, it’s not a big issue because installing the switch either way around will work. However, replicate how the wiring on the old switch was installed when installing the new switch.
Tighten the screws holding the wires using a screwdriver until they are firmly in place, enough so that the wire will not slip away.
Tip: Make sure the exposed metal parts of the two electrical wires don’t touch each other. If the wires touch, this could cause a short circuit when the power is turned back on and trip the circuit breaker, causing the new switch and other switches, lights, outlets, and appliances that are also connected to the breaker not to function. It could also cause a shock, and we certainly don’t want that!
If the exposed metal part of the wires is all chewed up, you can cut off the wire’s damaged portion using wire cutters or strippers. After doing so, strip off a ¾ inch section of the wire insulation using the wire strippers to have access to the workable, exposed wire. Bend the newly exposed wire into a U-shaped loop with the wire strippers. Needle-nose pliers also work well. Ensure there is roughly ½ inch of exposed metal at the end of each wire. The metal wire must have full contact with the screw for it to operate.
Info: With many switches, there are holes in the back of the switch that you can slide the wire into, but we recommend attaching the wires using the screws on the sides of the switch. Wrapping the wires is easier to remove and less likely to come loose after extended use. This is because there is more metal to metal contact using the screws, preventing connection issues and switch failure.
Reinstall Ground Wire
Attach the copper ground wire by closing it around the green screw in a tight U shape on the new switch using wire strippers or needle-nose pliers. Use a screwdriver to tighten the green screw on the single pole switch until the ground wire is securely in place.
Fasten The New Switch
Once the three wires are attached to the new single pole light switch, slide the wires back into the switch box and screw the switch into place using a screwdriver.
Alternate between tightening the top and bottom screws to ensure it is evenly attached to the switch box. If you fully tighten one screw at a time, the switch can often become angled instead of being nice and flat against the wall.
Avoid over-tightening the screws as it can damage the electrical box, switch bracket, or drywall.
Attach New Cover Plate
With the switch snug in its new home, it’s time to attach the switch cover plate. Line up the holes in the cover plate with the holes in the switch box, and use a screwdriver to fasten the screws.
When changing from a toggle to a rocker (square style) switch, use the new rocker plate to cover the light switch.
Again, don’t over-tighten the screws, as this could potentially crack the cover plate. Simply ensure that the cover plate is flush against the wall, looks great, and won’t come loose from enthusiastic light switching for years to come. When you’re finished, turn the electricity back on from the breaker switch at the electrical panel.
Let There Be Light!
Now that you’re a light-switching pro and you’ve now gained the confidence to tackle other electrical work in your home, it’s time to turn on those lights, have some people over, showcase that confidence, and flaunt your electric personality! Everyone is sure to be shocked at how much better your light switches are than theirs. Okay, maybe not, but at least your lights will reliably turn on and off when you want them to, and that’s a win.