Simple Steps to Remove and Wire a Two-Way Double Switch

A double-switch allows you to operate two lights or appliances from the same location. Double switches, sometimes called "double pole," allow you to separately control the power being sent to multiple places from the same switch. For example, you might want to turn on a bathroom light separately from the ceiling fan. Though it is not difficult to wire a double switch, careful attention to safety is crucial to prevent injury. This wikiHow article teaches you how to wire a double switch with expert tips from professional electrician Ricardo Mitchell.

Note: This article only describes installing the switch itself, not rewiring two conjoined feeds that need to be separated. If you are trying to separate two lights that use the same wiring, as opposed to two already separate sources, you will likely need a trained electrician.

Quickly Wire a Double Switch

Cut the power to the light switch.
Unscrew and remove the light switch from the panel.
Disconnect the wires from the old light switch.
Connect the ground wire to the green terminal.
Connect the hot wire to one of the black terminals.
Connect the two neutral wires to copper terminals
Screw the light switch back in and restore power.

Part 1

Part 1 of 3:

Removing Old Switches

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1
Cut the power to the room you're working in. Head to your circuit breaker and turn off the flow of electricity in the room you are working in. Usually, the correct circuit is labeled, but if it is not, you should turn off all the power in order to be safe.^{[1]
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- The energy going to a switch is nothing to scoff at, and it can cause serious damage if you come in contact with it.
- You should still wear gloves and ground yourself. Wear rubber-soled shoes in order to be safe while working.
Use Phillips screwdriver to unscrew the face plate from the light switch. Set the screw and face plate aside. You should see the switch with the wires behind it.

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3
Use a voltage detector to confirm that no power is reaching the wall. Touch the device to the old light switch or any exposed wires to ensure that there is no power coming to the wall. Some contractors will lump certain rooms together when wiring, meaning that a nearby bathroom that you thought was turned off could have several wires hooked up to the bedroom fuse.
- The safest way to check if there is power is to use a no-contact voltage detector. Simply touch the end of the detector to the screw terminals on the side of the light switch. If there is power, it will light up.^{[2]
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- According to Mitchell, you can use a multimeter to test the voltage. Set it for 120 V A/C. Touch the red lead to the hot wire going into the light switch. Then touch the black lead to the ground or a neutral terminal. See if the multimeter is reading any power.^{[3]
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- Always check and double-check that there is no power coming to you when you work. You can never be too careful when working with electricity.
4
Unscrew the old switch and remove it. Remove both screws and set them aside for later. Pull off the fixture gingerly, removing it from the small switch box embedded in the wall. There should be three or four wires attached to screws on the switch.
- The feed or hot wire is the wire that contains electricity. This wire sends electricity to the switch, which then controls whether or not to send electricity to the light, fan, etc. They are often, but not always, red or black They connect to the side of the switch with a small metal tab, or “fin.” Hot wires usually connect to the black screws. There may be one or two hot wires.
- There will be two neutral wires connecting to your two appliances, and each one will correspond to one of the switches on your double-switch when you are done. They are often, but not always, white. These usually connect to the brass or copper screws on the switch.
- The grounding wire, which is often green, yellow, or bare copper, and is attached to a green screw. It helps to protect the switch and your house from an electrical short. Because it was not always legally required in all houses, some switches may not have grounding wires.^{[4]
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If you're not an experienced electrician, take a quick picture of the fixture to determine how the wires are placed. You could also draw a simple diagram. Note each wire and the location it is attached to.
6
Unscrew and detach all of the wires from the old switch. The wires are held in place by screws, often called "terminals." The screws are tightened to clamp onto the exposed end of the wire, completing the circuit and powering the switch. To remove the wires, unscrew the screws and remove the wires from the screw terminals.
- In some cases, the wires may be soldered to the switch or permanently connected via a push connector. If this is the case, simply cut the wires at the switch and strip off about ¾ of an inch from the remaining wire insulation.
- If you can keep the wire bent into its current shape, it may be easier to attach later.
- You should have 3 or 4 exposed wires coming out of the switch box.
This is likely how two lights or appliances have been run to the same switch. One of the wires, for example, might be for your fan, and the other for the light. These two conjoined wires are wrapped or joined at the terminal and wrapped around the same screw. They are likely your two feed wires, and will need to be installed on separate terminals later on.

Part 2

Part 2 of 3:

Installing a Double Switch

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You're going to need to test the wires now, and if they are touching the metal switch box or the walls, you could cause a short. Let the wires dangle out into open air. You're going to have to turn the power on to test which are the feed wires if you're unsure.
2
Turn the power back on to find the hot wire if needed. If your wires are not labeled, you'll need to find out which wire is feeding electricity to your switch. Remember, however, that the hot wire is usually black or red, while the neutral wires are usually white. It’s still a good idea to double-check to make sure. To figure out which is which without colors, turn the power back on at your location. Using a voltage detector, touch the end of each wire. The wire(s) that cause the detector to light up are the hot wire(s). Turn off the power before marking this wire.^{[5]
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- Be extremely careful with these wire while the power is on. Only touch them with your voltage detector, and be sure to wear insulated gloves while working.
- According to Mitchell, you can use a multimeter to check which wire is the hot. To do so, set the meter to 120 V A/C and touch the red lead to the bare wires, and touch the black lead to the ground wire. Whichever wire(s) read a voltage are the hot wires.^{[6]
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- Once you know which wires are which, be sure to turn the power back off at the breaker box.
- There may be one or two hot wires. This will determine how you wire your switch.
3
Determine which side of the switch is for hot wires and which is for neutral wires. There is a metal, rectangular tab on most double switches that indicates which side is for hot wires. This is where you need to connect your appliances. The other side is for the feed wire and gives the switch power.
- Frequently, the hot wire terminals (screws) are black or silver.
- The neutral side terminals are usually copper.
- The green screw is for the grounding wire.^{[7]
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- Check the instruction manual that came with your switch if you are not sure which terminal is which.
4
Bend the ends of the wires into a hook shape and hook them under the screws. You want the wire bent in a clockwise direction. This allows it to turn with the screw as you tighten the screw down. It does not matter which wires you attach first, but it is not a bad idea to start with the ground wire.^{[8]
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- Only attach one wire to each terminal.
- Make sure you remember to attach the grounding wire.^{[9]
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- One hot wire configuration: If there is only one hot wire, attach it to the top terminal on the switch, and then screw the other terminal screw down without attaching a wire. The tab in between the terminals will feed the power to both switches. There should be two neutral wires that go to each light fixture or outlet. Attach both wires to the neutral terminals on the switch.
- Two hot wire configuration: If there are two hot wires, you’ll need to break or remove the tab in between the hot terminals and attach a hot wire to both terminals. Then attach the neutral wires to the neutral terminals.
5
Screw the terminals down on the wire so that they do not move. You want the wire to fit snugly under the terminal so that it has a good, solid connection. Tighten each screw down so that the wires cannot move.
- Give each wire a firm tug to make sure it is secure.
6
Turn the power back on to test the connections. With both switches in the "off" position, turn the power back on and check each switch individually. They should immediately power up the attached appliances.
- Be sure to wear insulated gloves when testing the switch while the power is on. Do not touch the wires or anything metal on the switch.
Wrap a piece of electrical tape around all the terminals, protecting them from potential shorts.
With the power still off, place the fixture back on the wall and screw it in with the provided screws. Turn the power back on and celebrate -- you have a new double switch.^{[10]
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Part 3

Part 3 of 3:

Troubleshooting

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1
Turn the power back off before you begin troubleshooting. If you are removing the fixture or unscrewing anything, be safe and cut the power to the area you are working on. Use your voltage detector to make sure that there is no power in the switch before proceeding.
- Make sure you check the light bulb and appliance before continuing, as the problem may not be with the switch.
This will short the connection and prevent electricity from getting to your light.^{[11]
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3
Check the connections of the wires. Most issues are due to a bad or loose connection. Partially unscrew the hot wire and both neutral wires. Make sure they are hooked tightly around the screw before tightening them back down.
- Use a pair of needle-nose pliers to clamp the ends of the wire around the screw.
- Make sure there is enough wire exposed to make a connection with the terminal. Use a pair of wire strippers to expose at least 1/2-inch of wire.
- If the end of the wire is frayed or nicked up, cut it off, strip another inch of insulation off, and use this end.^{[12]
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4
You may have multiple hot feed wires. This is common with some older boxes, when you have two single switches hooked up instead of one double switch. A hot wire (red or black) comes out of the wall and into one switch, then out of that switch and into the other one. It may, in some cases, even return to the wall from the second switch. Don't let this discourage you -- simply attach the hot wire on the new fixture exactly how you found it on the old wire. This is why there are often two terminal screws on the feed side.
- Some electricians will cut the wire covering in the middle, loop the wire in the terminal, and allow the rest of the wire to continue into the wall. You should do the same thing if you see this is the case in your old switch.
5
Make sure that you have the feed wire connected to the right side of the switch. If checking your connections still doesn't work, you should make sure that the feed wire is in the correct side of the switch. If your switch does not have it labeled, it is the side with the metal tab, or "fin." The screws are usually black.
- If there are two black terminals on the same side, it does not matter which one you attach the feed to.
- If you are still struggling, reverse the connections or check the manual included with your new switch.
Many older houses won't have ground wires, but this is okay. The box is grounded to the house already, meaning you won't need one.

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Question

What are the white wires?

Ricardo Mitchell
Electrician & Construction Professional, CN Coterie
Ricardo Mitchell is the CEO of CN Coterie, a fully licensed and insured Lead EPA (Environmental Protection Agency) Certified construction company located in Manhattan, New York. CN Coterie specializes in full home renovation, electrical, plumbing, carpentry, cabinetry, furniture restoration, OATH/ECB (Office of Administrative Trials and Hearings/Environmental Control Board) violations removal, and DOB (Department of Buildings) violations removal. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience.

Ricardo Mitchell

Electrician & Construction Professional, CN Coterie

Expert Answer

If your wires were installed by a professional, the white wires are almost always going to be neutral. All of those neutrals get spliced together.

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Why do I have to have both switches in the on position for the outside light to work?

Community Answer

This issue can occur if a traveller is mixed up with the line feed; or if only a 2-wire was pulled between the two switches; or where the feed comes to the light first, and the two switches aren't linked correctly. Because this level of troubleshooting requires a live circuit to determine what's what, call a qualified electrician to do this repair.

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What wires need to be moved to turn on a light with one switch and a fan with another?

Community Answer

You will need an additional wire up to the fan.

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Tips

Be sure to read the instructions on the switch and on the fixtures to which you are attaching because you need to determine the amps required; they must match those powered by the switch and by the conduit wiring.

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Mark the wires with masking tape once you know what they do so that you don't get confused later.

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Place a piece of electrical tape across the circuit breaker once you have it turned off in order to warn others not to switch the breaker on.

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Warnings

If you feel at all uncomfortable working with electricity, call an electrician.

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Anticipate emergencies and have a first aid and emergency response kit on hand, even if you think you can handle things.

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If you discover your wiring is aluminum, stop work immediately and contact a wiring professional.

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Let everyone in the household know that you are working on the electricity.

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