Hook up 3 way switch
Lost your password? Please enter your email address. You will receive a link and will create a new password via email. Before you begin anything with a three-way, you must understand that in order for you to have a three-way circuit you must have three-way switches. They are not the same as a regular switch at all.
How to Wire a 3-Way Switch: Wiring Diagram
Dan has been a licensed journey-level electrician for some 17 years. He has extensive experience in most areas of the electrical trade. Wiring a 3-way light switch is not a difficult task Making them at the proper place is a little more difficult, but still within the capabilities of most homeowners, if someone shows them how. That's where understanding a wiring diagram can help. When you want to be able to control a light from two different locations for example, you want to be able to turn the stair lights on from both upstairs and downstairs , this is what electricians call a "three-way switch.
To replace a switch is not difficult at all: Simply watch how you disconnect the old one and then put the wires back on the new light switch in the same position. Problems can arise when an extra switch is being added or if you forget which wire went where. That's when it becomes necessary to understand a little more about how a 3-way switch works and how to read a wiring diagram.
If you know what the purpose of each wire is, the task will become much simpler. This article will explain everything you'll need to know in order to wire a 3-way switch, with wiring diagrams and common wiring methods explained. Read How to Wire a 4-Way Switch for instructions and wiring diagrams for wiring four-way switches. The small, green screw terminal on the bottom is the ground terminal. All new switches must have a ground, but some older ones don't. One of the three screw terminals will be a different color, usually darker.
This is the common terminal. The white wire is the neutral. You'll bundle all the neutrals together with a "wire nut" or a twist-on plastic wire connector. The black wire is "hot" at all times unless the entire circuit is turned off at the circuit breaker panel. A note about wire colors: The National Electric Code requires that every neutral wire be colored white, and that ground wires be colored green. Only neutral wires may be white in color, but the code makes an exception for white wires in a cable that are not being used for a neutral.
These wires should be colored black using a magic marker or some other method. Many electricians will do this, but many will not, and it can make troubleshooting in the future difficult and can be a safety hazard to anyone else working on the system. I encourage you to take the few seconds necessary to color these non-neutral wires. The colors shown in these wiring diagrams are common color usages only.
Not all electricians use the same color code except for neutrals and grounds , so the wires could be different colors. The terms "traveler" and "common" have already been explained, but there are other terms that will be used in this article that also need some explanation. Each diagram will show the two 3-way switches but not the wall box they are contained in , the various cables and wires used in the configuration being discussed, and the light box and light fixture.
To understand the wiring diagram, you must know that the electrical current enters the system on the black wire in the power-in cable, passes through the switches, through the light fixture, and returns to the white wire in the power in cable. If the circuit is broken anywhere a switch turned the wrong way, a broken wire, or a bad light bulb , the current will not flow and the bulb will not light. For discussion purposes, each 3-way switch will be considered to have the common terminal connected to the right-hand traveler terminal when in the "up" position and connected to the left-hand terminal when in the "down" position.
This is not necessarily true, however, it's simply helpful for discussion purposes. Read the descriptions carefully and compare them to the diagrams to understand the diagrams. Each diagram will have a description of how the current travels in order to light the lamp. A non-contact voltage tester is an invaluable tool here for working on electrical circuits. Both Fluke and Klein make professional-quality testers, and cheaper ones are commonly available as well.
As a professional electrician for some 20 years, there is always one in my pocket, and anyone working around electricity should carry one as well. Once the correct location of each wire is determined using the wiring diagrams below, the light switch is connected to proper wires and installed in the light switch box.
Make sure the power is off before making any connections! Many residential light switches have a small hole in the back of the switch that wires can be pushed into, and all switches have the screws on the side. The picture of the older switch above has both the push-in holes and screws; the other is an expensive switch that has holes to insert wire but the screws must be tightened as well.
Many switches have only the screws, with no holes. There is a "strip gage" on the back of the switch; it shows how much insulation is to be stripped off if the push-in method of connection is to be used. If the screws are to be used, a little more insulation needs to be removed. In this example, the power-in cable enters the light box. This method of running the wire is common when several light fixtures share one common breaker, and the switches are both on the same wall. Cables need to be run into the light box, between the two switches, and from the light box to just one of the switches.
A note about the color of the wires: In this example, the only neutral wires are the white wire in the "power-in" cable which is always a white wire and one of the two wires attached to the light also always white. All other white wires should be colored. In this 3-way switch wiring diagram, the power-in line enters the light box, but 3 rope cables are then installed between the light box and each switch box. This method might be used when power is available in the ceiling but switch boxes are on opposite walls—it is often easier to run the cable up into the ceiling light box instead of between switches.
This time the electrician has brought power into the first switch, through the second switch, and on to the light fixture. This is a reasonable method for cases with multiple switches in the same box, as other switches then have power available and can operate other lights without having to have a separate power in line run to them. The major difference here is that the neutral from the power-in line has to be taken to the light fixture via the 3 rope. The white wire must be used here, as code requires that all neutral wires be white.
This example shows the power-in cable entering the first switch box along with the cable to the light fixture. This can result in a lot of wires in this box, but can be helpful when the light is near the first switch box. A larger box may be necessary to contain all the wires. Recent code changes require that each switch box have a neutral wire in it. This means not only a white wire, but a white wire that is connected to the white wire on the power in cable.
This rule is intended to provide future capability for the use of a dimmer or other device that may need a neutral wire and stop homeowners from disconnecting or using the ground wire for other purposes. New work such as adding a new three-way switch will need to comply with this code. The only wiring diagram shown here that is legal to use is 3, although 1 could be modified by adding a 2-wire cable from the lower box to the light.
Any neutrals in the switch box that are unused are either spliced together or, in the case of a single neutral, simply capped off with a wire nut and tucked back into the box. Simply replacing a switch does not mean that the room needs to be re-wired, as the existing wiring is "grandfathered in" and is acceptable. Old work does not need to be re-done to comply with the code and is this why the unacceptable by current code wiring diagrams are discussed here in this article.
In general, switches are not difficult to replace or install, and most homeowners are quite capable of doing it. For more help and guidance, read Installing or Replacing a Light Switch. If you are adding a new light fixture to work with your new 3-way switches and want some help, read Installing and Wiring a Light Fixture. Regardless of whether you are replacing a switch or installing new switches in a major remodel, probably the most useful tool to own is a non contact AC voltage detector.
Make sure that whenever you do any kind of electrical work that you first test with a good voltage detector. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters. My three-way switch is over fifty-years-old.
There is a white wire on one side of the box on the bottom , and a red wire on the same side top. On the other side, there is a black wire top. The new three-way switch box has a green screw at the bottom on one side, and a black screw on the other side at the bottom, with two gold-colored screws at the top. Can I attach the wires to the new box in the same place as the old, regardless of colors? Yes, but you didn't mention a ground wire on the green screw for the old switch.
It's very doubtful it has one. If not, the new switch should get a ground wire to that green screw, which will mean finding a source for a ground wire and running it to that switch. Electrical code requires every switch have a ground wire now even though grounds were not used for many years. Other than that, hook up the wires the same way. The worst case scenario is that the switch will not work properly, after that you will swap a couple of wires and try again until it DOES work correctly.
It's always fun trying to decipher what an electrician or homeowner did fifty years ago! How can this happen? As traveler wires go from one traveler terminal on one switch to a traveler terminal on the other switch, it is not possible to remove both ends from the switches and have the wire be hot. It is not connected to anything at all, and cannot be hot.
What kind of tester are you using to determine if a wire is hot? The non-contact testers mentioned in the article can be sensitive enough to pick up static electricity transferred from one wire to another even though they are not touching. They are intended to ensure a wire is dead, and I've never had one give a false negative showing a dead wire , but the price is that occasionally they can show hot when a wire is not. If the wires are hot when disconnected, then there is another source of power that you have not identified yet, and the wires are going somewhere you are unaware of.
It is doubtful that it is a 4-way switch - those have four terminals on them plus ground , and they are all travelers. No power line should ever terminate on a 4-way switch. On a three-way switch, can it just be grounded in the box, or does it need to go to the box and then to the switch? Can it just go to the box?
My house is wired just to the box, but I have been told it should also go to the switch.
Take a closer look at a 3 way switch wiring diagram. Pick the diagram that is most like the scenario you are in and see if you can wire your switch! Interested in a 4 Way Switch Wiring Diagram?. This option is very similar to option #1 when wiring a 3 way switch. Here I am showing how to hook some lights up in series. If you need more than two lights, just.
Three-way switches require a three-wire cable: The cable should also have a ground wire, or a total of four wires in the cable. The system also requires three-way switches.
This page describes how to use 3-way and 4-way switches to control lights from two or more locations. This is the first of several related pages explaining how to control lights with multiple switches.
In building wiring , multiway switching is the interconnection of two or more electrical switches to control an electrical load often, but not always, lighting from more than one location. For example, this allows lighting in a hallway, stairwell or large room to be controlled from multiple locations.
Most of us take for granted the ability to turn a light fixture on or off from the bottom or top of the stairs, or from two different entrances to a room. But a wall switch that allows this bit of magic is not a standard switch. It is called a 3-way switch , and it is wired quite differently from standard—or single-pole—switches. The thing to remember about 3-way switch wiring is that 3-way switches are always used in pairs. In other words, if a circuit has 3-way switches, it always has two of them. If there are other switches on the same circuit, these must be 4-way switches; 3-way switches are not used on the same circuits with standard single-pole switches.
How to Wire a 3-Way Switch: Wiring Diagram
I am new to the community and I have recently start my home automation with Smartthings and start expending home automation by adding more Z Wave light switches. It seems like the slave light switch box does not have any power feed to it. When it comes to wiring, you cannot believe anything. You have to make sure. What you are missing at the switch boxes is a neutral wire. The Leviton requires a neutral wire at the switches to operate. Thank you all for the comments. You could place a Fibaro Dimmer 2 micro module behind the main switch the one shown on the left of the diagram. It doesent need a neutral.
Definitions of terms: The hot wire from the breaker usually black Neutral:
Dan has been a licensed journey-level electrician for some 17 years. He has extensive experience in most areas of the electrical trade. Wiring a 3-way light switch is not a difficult task Making them at the proper place is a little more difficult, but still within the capabilities of most homeowners, if someone shows them how.
How a 3-Way Switch Is Wired
Here are several variations of using 3-way switches to control lights from two locations. Colors are shown consistent with the NEC. Before reading this page, you may want to visit 3-way switches and 4-way switches. Below is a variation with the light between the two switches, i. In this case, the end of the white wire from the light box to the right switch must be re-marked black to indicate that it is a hot wire:. Next is a circuit with the light between the two switches, but with the panel feeding the light box. Note similar remarking to above. Any of the above can be modified to control multiple lights. Additional lights are just wired in parallel with the first, using two conductor cable. The black should be connected to the black wire feeding the light and the white to the white wire feeding the light in all cases. Here is one example.
Tutorial: How 3-way and 4-way switch circuits work
Notice that there is a 3-conductor cable coming into the first box, then a 4-conductor cable going from left box to right box, then a 3-conductor cable going from the right box to the load. Now for wiring, lets assume you're looking at the switch just like it shows. The Left Box: The lower left screw is the common and gets the black wire from the source 3-cond. The upper left screw gets the black wire from the right box 4-cond. The upper right screw gets the red wire from the right box 4-cond.
Help wiring a 3 way switch
No longer allowed after NEC if no neutral wire in switch boxes. Line voltage enters the first 3- way switch outlet box, light fixture is located between switch boxes. There is no standard for wire colors on 3- way switch travelers. The colors will vary depending on whether NM cable or conduit was used. With NM cable, the wire colors for travelers will be black and red using 3- wire cable. With conduit, the wire colors for travelers could be any color.
Three way switches have become very popular because it adds convenience and ease to lighting in large rooms, hallways and staircases. For more flexibility, add a four way switch. Take your time, mark the wires properly and you will not only be successful, you will stay sane. The first thing you will need to determine is where the power is coming from and where the switches are positioned. In this first example, the power is coming in to the first switch, flowing along to the second switch and ends at the light. The ground wire will always be attached in each box and flow right to the end fixture. This option is very similar to option 1 when wiring a 3 way switch.
3-way switch circuits -- Variations
.How To Replace A 3-way Light Switch