How To Wire A 3 Way Switch - Conquerall Electrical Ltd (2023)

Wondering how to wire a 3 way switch? Well you came to the right place. Let the professional electricians help you and make things simple.

In total the three way has a set of travelers that transfer the power from location to another. How to wire a 3 way switch depends on the power feed location. This is common on staircases. New Code states that all switches including 3 ways must have a neutral present in the device box.

This is common so that newer dimmers can be installed. Most new electric switch devices require a neutral connection.

How To Wire A 3 Way Switch - Conquerall Electrical Ltd (1)

1.How To Wire A 3 Way Switch

Common methods to wire a 3 way switch would be too bring your feed from your fuse panel or power box. This will be done with a piece of 14/2 nmd 90.

The neutral wire would continue on through both 3 way switch boxes and terminate at the light fixture. Black wire of the feed coming from the panel. Would terminate on to the black common screw of the first 3 way inside your first box.

The other 2 wires in the 3 wire that connects between both boxes will get help to the travellers of both 3 ways. This would be the red and black wires as you have already used the white wire for your neutral.

These 2 wires we’re going to copper screws of both 3 ways. From the last 3 way to the light itself you will have one black wire left. This black wire will hook on to the common of the last 3 way. hey

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2. Old Methods How To Wire A 3 Way Switch

How To Wire A 3 Way Switch - Conquerall Electrical Ltd (2)

Since the release of the 2018 electrical code . The code states that you must have a neutral present in all switch boxes. This is to allow for new style dimmers and a variety of smart light switches.

So long story short where do you wire the power through the switch boxes or whether you wire through the light fixture. You must have that neutral present in each which box. This can be done by simply wire nutting a tale onto the neutral as it passes through the box.

3.New Code Methods How To Wire A 3 Way Switch

How To Wire A 3 Way Switch - Conquerall Electrical Ltd (3)

4.Wire the 3 way with power in the switch

When wiring a 3 way with power in the light do you need to take a little different step. Power from the panel with 14/2 would come into the light box first or the octagon.

The white wire from the power panel would help directly on to the light fixture. Keep in mind if you’re following the new electrical code. You will need to run a piece of 14/3 down for what we called switch leg to switch boxes. This is so that you can carry down the neutral to the switch box.

The black wire from the piece of 14/3 running to the switch box should go all the way down to the first switch. This should have gone to the common black screw of the first 3 way.

Again between the 2 switches you will need that piece of 14/3 wire. The two travellers will again be here black and your red. From the second 3 way you will run the common wire backup on you’re red wire to the light fixture. This is because you’ve already used the black to go to the first 3 way. Sometimes this can be a little confusing.

We do one wire to time colour by colour and use the process of elimination.

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How To Wire A 3 Way Switch - Conquerall Electrical Ltd (4)

5.Wire the 3 way with power in the light

Different types of 3 way switches

Different types of 3 ways that you will see in the store or installed in someone’s house . They are sometimes hard to tell what day are. A typical toggle 3 way just looks like a regular switch what is no indicator button to tell you when it is off. These are the most common 3 ways that you will see in homes.

A step up from this 3 way would be a decora style. Often referred to as a rocker switch this which is also have no indicator for up and down. Depending on which way they have 3 way is switched it will always be in a different position.

Wireless 3 way switches have been around for about 10 years . These types of 3 ways do not need to have travellers running between them. Providing you have a power source at each box.

The 3 ways communicate over the neutral line within the house. Finally the newest type of 3 way would be the smart switch. It’s really hard to call this type of switch 3 way because you can have multiple switch locations.

Anywhere in the house there is a power source available you can put one of the switches. The switch is simply program to your Wi-Fi. Providing one of the switches is talk to a light that you wanna control. You can control that light from several locations. You can even controller from the app on your phone.

6.How To Wire A 3 way Switch With Multiple Lights

Wiring a 3 way switch to multiple light fixtures is pretty much the same as wiring it with one light fixture. After running power to your first 3 way. Then running you’re 3 wire with your travellers.

You will terminate from the last comment do you like fixture. Simply run from the light fixture to the next light fixture and so on. Wiring all the black wires and all the white wires together in each light fixture.

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7.What Kind Of Wire Do I Need For A 3 Way Switch?

Typically will use a piece of nmd 90. This is sometimes referred to in the US Romex or lumex. This type of wire should be 14 gauge 3 conductor. It actually has 4 wires inside. Usually a white a black and a red a company by bare copper ground wire.

Sometimes this wire also comes in a 12 gauge version . This is for larger lighting loads up to 20 amp. Make sure if you use this kind of wire that your 3 way switches rated for 20 up as well.

8.Why Is It Called A 3 Way and Not A Two Way?

The technical term is actually called a 3 way switch. This means that you can switch device like a light fixture or an from to locations.

Many people call this type of switch a 2 way switch because you can switch from 2 locations. Sometimes it gets confusing for customers.

9.What Kind Of Electrical Box Do I Need For A 3 Way

Any device box rated for switch is suitable for a 3 way. 1104 l or at 1104 lht. Plastic device boxes are also a common items used in the industry these days. You can even use a larger device box with reducer plastering. You can see more on our recommended products here.

10.Do I Need To Use The Screws Or The Terminal Tabs On The Back Of The Switch

Important yes you need to use the terminal screws on the back of the 3 way. Do not use the pinch down connectors on the switch itself. This is frowned upon in the industry and called taking the easy way out. The problem is when you load the switch up with power the little tabs become weak.

This causes arcing and eventually heat and fire.

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11.What wires go where on a 3-way light switch?

A 3-way switch is a device that controls power to two lights or fixtures. There are three wires in the device. Two of the wires are connected to one 3 way or travelers, and the third wire is connected to the other 3 way.

Which wire goes where at the three way switch depends on how power is being fed into the box.

If power comes into the box from below, then white goes to white, black goes to black, and red goes to center screw terminal. If power comes into the box from above, then black goes to black, white goes to white, and red wire goes to center screw terminal. White is not always the neutral wiring in this case.

12.What happens if I wire a 3-way switch wrong?

Wiring a 3-way switch incorrectly can lead to serious consequences. If the wiring configuration is incorrect, you could ultimately damage your home wiring, create a fire hazard, or even shock yourself!

A 3-way switch is wired in conjunction with two other switches—a “traveler” and the “target.” The traveler will be wired either up (if you’re wiring 2 switches on opposite sides of the room) or down (if you’re wiring 2 switches on the same side of the room). The target will be wired in between the traveler and the 3-way device box.

If you wire a 3-way switch incorrectly, it’s important to know that power will not flow through it. This can create unsafe conditions for your family and home. For example, if you wire a 3-way switch up when it’s actually down, then power won’t travel from the device box to where it needs to go. There are also many cases in which electricity will flow backwards through an improperly wired switch, which could cause fires or shocks.

To avoid these hazards, always consult with an electrician before you attempt any electrical work around your house. And if you have any questions about 3-ways—or any other type.

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13. What is the black screw on a three-way switch?

A three-way switch is a type of light switch that controls power to a load from two possible sources. This is common when wiring a staircase when the power feed for lights is on one side, but the light fixture on the other.

The black screw in the center is called the ‘common’ wire, and this wire must always be present in order to make it work. When installing this type of three way switch, there is often a red wire coming from one side and black coming from another side. The white wire with white stripe goes to the neutral bar at the bottom of your device box, or connects through to the light.While black goes to hot side or common screw.

14. Where does the neutral wire go on a 3-way switch?

If you have a power feed location at the top of the stairs you will need to install an additional switch. You will wire this new switch to the traveler side of your 3-way switch. Now when you turn off the upstairs light switch, the light downstairs should go out. Depending on the configuration the white wire is not always connected to the light.


What is the correct way to wire a 3-way switch? ›

Three-way wire(which includes red, black and white wires) runs from the switch on the left to the switch on the right, with the white wire carrying ground and the red and black wires carrying the output from terminals in the left switch. Normal sheathed cable runs from the right switch to the light.

What color wire should your 3-way switch be common? ›

Black wire: This is a hot wire that carries electricity from the power source to the first switch in a typical 3-way setup. It's also called the “common wire” or the “line wire.” Unless the breaker is off, this black wire is always hot.

Do both 3-way switches need neutral wire? ›

The other wires in a circuit with 3-way switches are the neutral (usually white) and ground (usually bare copper or green). The neutral wire bypasses both 3-way switches but connects to the light fixture. The ground connects to the ground terminal on each switch and to the light fixture.

How do you tell if a 3-way switch is wired wrong? ›

Follow these steps to find which switch is bad.
  1. Toggle each switch until the light come on. Toggle one switch to see if it turns the light on and off. If it does, it is a good switch. ...
  2. Toggle the other switch to see if it turns the light on and off. If it does, it is a good switch and the other is bad.

Which wire is the common wire on a 3-way switch? ›

The two lighter, brass-colored screws are called the traveler screws. The travel wires connected to these screws will offer two different pathways for power to travel from one switch to the other. The last screw is the common terminal. It is a darker color than the travelers, usually dark brass, copper, or black.

Does it matter where the traveler wires go on a 3-way switch? ›

The hot wire from light always goes to the common terminal of the second switch. The traveler wires go from switch to switch connected to the traveler terminals, it doesn't matter which. As long as you keep this in mind, a 3-way circuit becomes really simplified.

Does it matter which wire goes where on a switch? ›

Because the switch terminals are interchangeable, it doesn't matter which wire you put on each.

Where does the black wire go on a three way switch? ›

Figure A: 3-Way Switch Wire Diagram — Power to Light Fixture

The black hot wire connects to the far right switch's common terminal. Red and blue wires link traveler terminals of both switches. The red wire, which is connected to the first switch's common terminal, leads back to the fixture.

How many common terminals does a 3 way switch have? ›

They are wired so either switch can work the light, regardless of the setting of the other. A 3-way switch is larger than a single pole switch and has three screw terminals for wiring connections, plus a ground.

Is the black screw on a 3 way switch the common? ›

When disconnecting the wires, mark the wire on the black or dark colored screw as common. Mark the wires on the brass or light colored screws as travelers. Make notes or take a picture to verify connections before removing the old switch. Mark the wires on the brass or light colored screws as travelers.

Can 2 outlets share a neutral? ›

This is also known as a common neutral, and the circuits and neutral together are sometimes referred to as an Edison circuit. In a 3-phase system it is legal in some jurisdictions to share a single neutral wire between all three (3) phases. One neutral may not have two “hot” wires from the same phase.

Will a 3 way switch work if wired wrong? ›

Yes. The switch should be on the hot, not the neutral, wire. It's a safety thing. A switch will work on the hot or the neutral, but if you switch the neutral, the light fixture is still electrically live even with the switch turned off.

Do 3 Way switches need to be grounded? ›

Neutral wires are always white, and white wires not connected to the white power-in wire should be colored some other color. Ground wires are always green or bare of insulation (copper). Each switch, as well as the light fixture, must have a ground wire terminated to it.

What happens if you wire a switch the wrong way? ›

But here's the catch: If you connect the circuit wires to the wrong terminals on an outlet, the outlet will still work, but the polarity will be backward. When this happens, a lamp, for example, will have its bulb socket sleeve energized rather than the little tab inside the socket.

What happens if you wire a 3 way switch backwards? ›

A light switch has no polarization so when you reverse the connections on the light switch it works just as before you reversed the wires.

What happens if you wire live and neutral the wrong way? ›

There would be a shock hazard, and some devices might not work correctly. Depending on where exactly the wires are flipped, ground fault detecting circuit breakers may become ineffective. All around, this is a bad idea. Save this answer.

What are the 3 terminals of a 3 way switch? ›

3-Way Switch – a 3-way switch has 3 terminals: 2 brass terminals for the 2 traveler wires, and 1 common (black) terminal for the common wire. A 3-way switch circuit is always comprised of two 3-way switches that control light(s) or device(s) from two different locations.

What color should traveler wires be? ›

Blue wires are used as travelers, usually on three- or four-way switches (controlling a light from multiple locations) or as switch legs for things such as fans or lights. Yellow wires are almost always used as switch legs for outlets, fans, or lights.

Can there be 2 hot wires on a 3 way switch? ›

You will ALWAYS have 2 hots on a 3 way switch. You have power in and power out. There is no "off" on a 3 way switch. switch to the other position means ONE "ON" is connected to the load.

Which wire goes to which? ›

Basic Wire Color-Coding

A black or red-hot wire usually connects to a brass-colored screw terminal or black wire lead on electrical devices. A white neutral wire usually connects to a silver-colored terminal or white wire lead.

In which wires which should be connected? ›

Switch should be connected to the live wire. Switch should be connected to the neutral wire.

Does the line wire go on top or bottom? ›

Load Wire - Generally connected to the top half of your switch. If the wire is coming from the top of the switch box, it is likely your load wire. Line Wire - Generally connected to the bottom half of your switch. In some cases, line wires are marked with “line”, “pwr”, or a lightning bolt symbol.

Does it matter what side the black wire goes to? ›

White (neutral) goes on the side allocated for the larger prong. Black (Hot) goes on the smaller prong side or white to silver screws, black to gold screws.

Where does the black wire go? ›

Power comes from the service panel along the black (hot) wire through other outlets, switches and light fixtures on the circuit and begins its return to the source through the white (neutral) wire. The black wire attaches to a brass terminal; the white wire, to a silver terminal.

Where does the black and red wire go? ›

Black wires are hot wires that run to the electrical outlet from the switch. Red wires are hot wires common in a 240-volt outlet or when a wall switch controls the outlet. Blue and yellow wires are hot wires for ceiling fans and three- or four-way switches. White or gray electrical wires are neutral wires.

How do you tell which wire is hot and which is not? ›

Hot wire is identified by its black casing. This is the main color of hot wire for most homes. However, other hot wires can red, blue, or yellow, although these colors can indicate a different function besides powering an outlet.

Which wire do you connect first hot or neutral? ›

First things first, you need a wire that will take power from the battery and connect it to the lightbulb. That wire is known as your hot wire. Of course, in order to complete the circuit, a wire must return the electrons to the power supply to turn the lightbulb on. This wire is *drumroll* your neutral wire.

How many poles and throws are on a 3 way switch? ›

The 3-way switch. This switch connects a single-line conductor to either of two possible switch legs. A common household example of this is in a three-way switch loop, which allows control of a single load (usually a light) from two different locations.

What is the white wire in a 3 way switch? ›

The common terminal of the second 3-way switch connects to the light fixture(s). The white neutral wires are connected together in each switch box.

Which wire goes to which screw? ›

Connecting to a receptacle

Wires on a receptacle must be connected to the correct terminals. The white wire always goes to the silver screw while the red or black wire goes to the brass screw. The bare copper wire (ground) goes to the green screw.

Can you use two wires with one neutral? ›

Note the stipulation that a shared neutral MUST be for two circuits fed from a two-pole, common-trip breaker. This ensures that the neutral current never exceeds the Ampacity of one of the two phases feeding the circuits.

Can two power cords be on the same wall outlet? ›

Daisy chaining is a term that refers to the practice of plugging a power strip into another power strip. This is dangerous because an excessive amount of power is being drawn from one single wall outlet, which means the power strip or wall receptacle could easily overload.

How many neutrals can be tied together? ›

300.3 references 310.4, tho 300.3 says all conductors of a circuit must be in the same cable, raceway, etc unless allowed elsewhere. Even if you meet that condition, you still cannot tie 2 or more #12 neutrals together.

What happens if you wire backwards? ›

With reverse polarity, the hot wire feeds electricity into the socket and you'll get zapped if you touch it. Inexpensive circuit analyzers will let you know whether an outlet is wired correctly.

Why does my 3 way switch sometimes not work? ›

Sometimes, a 3-way circuit doesn't work because someone tried to replace a defective switch and did not properly connect the wires. Sometimes, one of the switches has become defective.

What happens if I dont ground a switch? ›

The plug without a ground cable is dangerous because there is no alternative path for the charge to escape from the circuit. As a result, the conducting area is under the voltage. You then run the risk of coming into contact with the deadly excess charges that emit from power outlets.

What happens if you don't connect the ground wire? ›

The appliance will operate normally without the ground wire because it is not a part of the conducting path which supplies electricity to the appliance. In fact, if the ground wire is broken or removed, you will normally not be able to tell the difference.

Do you need a ground for every circuit? ›

They could damage attached electrical appliances, shock nearby people, or even start fires. Grounding is an important safety feature for any structure's electrical system. In fact, electrical codes require it for all new construction.

Is there always a hot wire on a 3-way switch? ›

A 3-way switch will be one of two such switches on the circuit, and either one can be flipped to turn on the light. For either switch to be able to route power to the light, it must have a hot wire connected. That means that both of the switches will always have a hot wire no matter which position the switches are in.

Which wire goes to black on 3-way switch? ›

The black (line) wire connects to the common terminal of the first 3-way switch. A 3-wire NM connects the traveler terminals of the first and second 3-way switch together. Traveler wires are interchangeable on each switch. The common terminal of the second 3-way switch connects to the light fixture(s).

What happens if you flip hot and neutral wires? ›

With reverse polarity, the hot wire feeds electricity into the socket and you'll get zapped if you touch it. Inexpensive circuit analyzers will let you know whether an outlet is wired correctly. The lights on these testers will indicate whether the hot and neutral wires are reversed.

How can you tell which wire is hot? ›

Hot wire is identified by its black casing. This is the main color of hot wire for most homes. However, other hot wires can red, blue, or yellow, although these colors can indicate a different function besides powering an outlet.

Does the black wire go on top or bottom? ›

Hook the black wire to the bottom terminal on the switch. Hook the white wire to the top terminal on the switch.

Does black wire go to blue or brown? ›

If you do have a fixture using international standards, the good news is that the matching is very easy. Brown is your hot wire so you want to connect that to your building's black wire. The blue is negative or return, so that will go to white.


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