First of all, before choosing and purchasing, you need to decide what it is - a pass-through switch, what it is needed for, and how it differs from the usual one, two and three-key switches.
A single-key pass-through switch is necessary to control one circuit or lighting line from several points located in different parts of the room or the entire house. That is, with one switch you turn on the lighting when entering a room or corridor, and with another, but at a different point, you turn off the same lighting.
Very often this is used in bedrooms. I went into the bedroom and turned on the light near the door. I lay down on the bed and turned off the light at the headboard or near the bedside table.
In two-story mansions, he turned on the light bulb on the first floor, climbed the stairs to the second and turned it off there. 
Selection, design and differences of pass-through switches
Before assembling such a control scheme, here is what you should pay special attention to:
1 To connect a pass-through light switch you need three-wire cable - VVGng-Ls 3*1.5 or NYM 3*1.5mm2
2 Do not try to assemble a similar circuit using ordinary switches. The main difference between regular and pass-through ones is the number of contacts. Simple single-key ones have two terminals for connecting wires (input and output), while pass-through ones have three! 
In simple terms, the lighting circuit can be either closed or open, there is no third option.
It is more correct to call a pass-through not a switch, but a switch.
Since it switches the circuit from one working contact to another.
In appearance, from the front they can be absolutely identical. Only the pass key can have an icon of vertical triangles. However, do not confuse them with reversible or crossover ones (more about them below). These triangles point in a horizontal direction. 
But from the reverse side you can immediately see the difference:
- the pass-through has 1 terminal on top and 2 on the bottom
- a regular one has 1 on top and 1 on the bottom
Due to this parameter, many people confuse them with two-key ones. However, two-key ones are also not suitable here, although they also have three terminals. 
The significant difference is in the operation of the contacts. When one contact is closed, pass-through switches automatically close the other, but two-key switches do not have such a function. 
Moreover, there is no intermediate position when both circuits are open at the gateway.
Connecting a pass-through switch
First of all, you need to correctly connect the switch itself in the socket box. Remove the key and the overhead frames. 
When disassembled, you can easily see the three contact terminals. 
The most important thing is to find the common one. On high-quality products, a diagram should be drawn on the reverse side. If you understand them, you can easily navigate through it. 
If you have a budget model, or any electrical circuits are a bit of a mystery to you, then an ordinary Chinese tester in circuit continuity mode, or an indicator screwdriver with a battery, will come to the rescue.
Using the tester's probes, alternately touch all the contacts and look for the one on which the tester will “squeak” or show “0” at any position of the ON or OFF key. It's even easier to do this with an indicator screwdriver. 
After you have found the common terminal, you need to connect the phase from the power cable to it. Connect the remaining two wires to the remaining terminals.
Moreover, which one goes where does not make a significant difference. The switch is assembled and secured in the socket box. 
Do the same operation with the second switch:
- look for the common terminal
- connect the phase conductor to it, which will go to the light bulb
- connect two other wires to the remaining ones
Connection diagram for the pass-through switch wires in the distribution box
Scheme without grounding conductor
Now the most important thing is to correctly assemble the circuit in the junction box. Four 3-core cables should go into it:
- power cable from lighting circuit breaker
- cable to switch No. 1
- cable to switch No. 2
- cable for lamp or chandelier
When connecting wires, it is most convenient to orient them by color. If you use a three-core VVG cable, then it has two most common color markings:
- white (gray) - phase
- blue - zero
- yellow green - earth
or second option:
- White gray)
- brown
- black
To choose a more correct phasing in the second case, follow the tips from the article "" 
Connect the neutral conductor from the cable of the input machine and the neutral going to the lamp at one point using the terminals of the car. 
Similar to the neutral wires, you combine the “ground” from the input cable with the “ground” of the outgoing cable for lighting. 
This wire is connected to the lamp body. 
The phase from the input cable must be connected to the phase of the outgoing wire to the common terminal of the pass-through switch No. 1. 
And connect the common wire from pass-through switch No. 2 with a separate wago clamp to the phase conductor of the lighting cable. 
Having completed all these connections, all that remains is to connect the secondary (outgoing) conductors from switch No. 1 and No. 2 to each other. And it doesn’t matter at all how you connect them. 
You can even mix up the colors. But it’s better to stick to the colors so as not to get confused in the future.
The basic connection rules in this diagram that you need to remember:
- the phase from the machine must go to the common conductor of the first switch
- and the same phase should go from the common conductor of the second switch to the light bulb
- the remaining two auxiliary conductors are connected to each other in the junction box
- zero and ground are supplied directly to the light bulbs without switches
Changeover switches - lighting control circuit from 3 places
But what if you want to control one lighting from three or more points. That is, there will be 3, 4, etc. switches in the circuit. It would seem that you need to take another pass-through switch and that’s it.
However, a switch with three terminals will no longer work here. Since there will be four connected wires in the junction box.
Here a changeover switch, or as it is also called a cross, cross, or intermediate switch, will come to your aid. Its key difference is that it has four outlets - two at the bottom and two at the top. 
And it is installed precisely in the gap between two passageways. Find in the junction box two secondary (not main) wires from the first and second pass-through switch.
You disconnect them and connect a changeover between them. Connect the wires that come from the first to the input (follow the arrows), and those that go to the second to the output terminals. 
Always check the diagram on the switches! It often happens that their entrance and exit are on the same side (top and bottom). For example, the connection diagram for a Legrand Valena changeover switch: 
Naturally, there is no need to stuff the changeover itself into the junction box. It is enough to lead the ends of a 4-core cable from it there. Meanwhile, you place the switch itself in any convenient place - near the bed, in the middle of a long corridor, etc. You can turn the light on and off from anywhere. 
The most important advantage of this circuit is that it can be changed indefinitely and add as many changeover switches as you like. That is, there will always be two passing ones (at the beginning and the end), and in the interval between them there will be 4, 5 or at least 10 crossover ones. 
Connection errors
Many people make a mistake at the stage of searching and connecting the common terminal in the pass-through switch. Without checking the circuit, they naively believe that the common terminal is the one with only one contact.
They assemble a circuit in this way, and then for some reason the switches do not work correctly (they depend on each other).
Remember that on different switches the common contact can be anywhere!
And it is best to call it, what is called “live”, with a tester or an indicator screwdriver. 
Most often, this problem is encountered when installing or replacing pass-through switches from different companies. If everything worked before, but after replacing one circuit the circuit stopped working, it means the wires were mixed up.
But there may also be an option that the new switch is not pass-through at all. Also remember that the lighting inside the product cannot in any way affect the switching principle itself.
Another common mistake is incorrectly connecting crossovers. When both wires are placed from pass-through No. 1 to the upper contacts, and from No. 2 to the lower ones. Meanwhile, the cross switch has a completely different circuit and switching mechanism. And you need to connect the wires crosswise. 
Flaws
1 The first of the disadvantages of pass-through switches is the lack of a specific ON/OFF key position, which is found in conventional ones.
If your light bulb burns out and needs to be replaced, with such a scheme it is not immediately possible to understand whether the light is on or off.
It will be unpleasant when, when replacing, the lamp may simply explode in front of your eyes. In this case, the easiest and most reliable way is to turn off the automatic lighting in the panel.
2 The second drawback is the large number of connections in junction boxes.
And the more light points you have, the greater the number of them will be in the distribution boxes. Connecting the cable directly according to diagrams without junction boxes reduces the number of connections, but can significantly increase either the cable consumption or the number of its cores.
If your wiring goes under the ceiling, you will have to lower the wire from there to each switch, and then lift it back up. The best option here is to use pulse relays.
Pass-through electrical switches, compared to conventional ones, are designed for complex and comfortable lighting control. They allow you to control one lamp from several places. For example, you have a long room in your apartment: you came home after work, turned on the light at the entrance, undressed and went to the kitchen, and at the other end of the hallway you turned off the light with the second switch.
The convenience of such control is that there is no need to return to the starting position to turn off the lighting. Until recently, pass-through switches were used only in extended structures - corridors, staircases, and suburban areas. Now they are installed everywhere. For example, in a bedroom, one electrical switch is installed at the entrance, and the second is located near the bed. I went in and turned on the light, went to bed and turned it off.
Operating principle and terminology
The concept of “pass-through switch” does not entirely indicate its functionality. If it is used for its intended purpose, then it is more logical to use the term “pass-through switch”. But both options have taken root in everyday life.
The wired switch looks no different from the standard one. The only difference is in the organization of the contact system. First, let's remember how a regular switch works. Its main purpose is to open and close a circuit. The purpose of the switch is basically the same.
The difference can be seen if you look at the symbols.
The figure shows that the switch is equipped with a third contact, the purpose of which is very different from the two-gang switch, which also has three contacts.
In fact, the difference in the operation of switches and switches occurs at the moment the electrical circuit opens:
- the switch breaks the circuit;
- the switch breaks one circuit and closes the second.
The second circuit in this case is the contacts of the paired switch, since these devices do not work independently.
Let's consider a diagram for connecting pass-through switches with control from two places.
The operating principle of the contacts of such a switch is similar to a rocker arm. By the way, switches with a zero position are rarely, but still found on the market, that is, two circuits can be open at once. The pass-through switch can be used as a regular one - in this case the third contact is not connected.
We will not consider the second option, when a regular switch is made into a pass-through switch. This was typical for 90 years, but now there are a sufficient number of models on the market at reasonable prices and experimenting in this direction is not entirely advisable.
Types of switches
The figures below show functional diagrams of various pass-through switches.
The most common options:
- single-key;
- two-key;
- three-key.
Also popular is a cross electrical switch, used for control from three or more places and consisting of two single-key switches paired with internal jumpers. A cross switch can be made from a two-gang electric switch by installing external jumpers. A crossbar has one key that simultaneously switches two contact groups, while a two-key crossbar has each key controlling its own group.
Connection diagrams to the electrical network
There are several switch connection schemes. The use of a specific circuit depends on the number of controlled luminaires and the number of control positions.
Control scheme from two places
First, let's look at the most popular scheme - control from two places.
To operate the switches, you will need to install three-wire wiring to each device. The distribution box is mounted opposite one of the switches. The following wires are inserted into it:
- power cable;
- cable of one switch;
- second switch cable;
- lighting cable.
There may also be another cable outgoing line, but in a simple diagram it is not taken into account.
Let's look at the connection diagram in the junction box.
Control circuit for two lamps
This scheme will allow you to control two lamps from two places. It is almost the same as the previous one, with the exception of the use of two-key switches.
To save money, you can install an external jumper for the second section of the switch, rather than laying two wires to the first switch.
Three-location control scheme
To implement such a circuit, you will need a pair of single-key switches and a cross switch. To operate the crossover, you will need a four-core cable or two two-core cables.
Control schemes from four or more places
If you add another cross switch to the previous circuit, then you can control the lighting from four places. It is switched on in series with the first crossbar.
Control circuit for two lamps from three places
This scheme has many disadvantages - a large number of connections and a lot of hassle in marking the cable cores.
All the considered diagrams show the initial position of the contacts of the transition switches.
This is essentially all that a novice electrician should know.
Pass-through switches are designed to turn lights on and off from different points. They can be installed in or more, depending on the need to create convenience on and off. First of all, such switches are installed in inconvenient places, such as long corridors, flights of stairs, etc. For example, in a long corridor, when you turn on the light with a regular switch located at the beginning of the corridor, you need to return from the other end to turn off the light.
The pass-through switch circuit allows you to turn on the light at the beginning of the corridor, and turn it off at the end of the corridor. To do this, two pass-through switches are installed.
2 position switch
The easiest option is to connect at two points. The basis of the circuit are two pass-through switches. Each of them has three contacts and a switch with two positions. The switching itself must be carried out in a changeover mode. In this case, one contact will be common to the other two. In each switching option, it alternately closes with one of the two remaining contacts. That is, all three contacts cannot be closed at the same time.
The connection principle in both diagrams is common. Each circuit includes pass-through switches, a junction box, a lighting device and connecting wires. Moreover, in different connection options, these can be cables with two, three or four cores. In a diagram with two switches, the neutral wire passes into the junction box from the power source, and then to the lighting device.
The phase wire, through a junction box, is connected to the common contact of a switch. The two switching contacts in both switches are also connected to each other via a box. From the common contact of another switch, the wire is fed through the box to the second contact of the lighting device.
Connection at three points
The three-seat pass-through switch circuit has very few differences from the two-seat circuit. A third switch of a different design is simply added to the circuit. If you press one key, then two contacts, independent of each other, will be switched simultaneously. This switch requires a cable with four cores.
The design of such circuits is quite simple and does not require any additional elements. There are certain restrictions on the number of control places. Practical installation is not particularly difficult. All elements are installed in their places at pre-marked points and then connected according to the diagram.
In this article we will take a closer look at how connect pass-through switches without a branch box.
After publishing a series of articles and videos on pass-through switches, many letters from readers began to arrive in the mail with the question: “Is it possible to switch it off without a branch box?”
Yes, you can get by without branch box. There are two main options here:
1. On pulse relays.
In it, the topic of pass-through and crossover switches is discussed inside and out.
So, wiring diagram for pass-through switches from two places without a branch box.
Instead of a junction box, all wires are brought together into the first socket box. Those. power from the electrical panel (zero, phase, grounding) to the socket box, a wire from the lamp to the socket box, and a wire from the second pass-through switch also to the same socket box.
Only in this case, a deeper socket box is needed, or the hole for it is made deeper, and the bottom is cut out in a standard socket box (so that there is somewhere to disconnect the wires).
The neutral and grounding wires from the electrical panel are connected in the first socket box, respectively, with the neutral and grounding wire from the lamp. They isolate themselves and hide in the socket.
The red wire from the lamp is connected to the red wire from the second socket box, insulated and also left in the socket box. This wire will supply the phase to the lamp. The remaining wires are connected to the terminals of the pass-through switches.
The central contact is indicated in the diagram by a number 1 . Wire colors may differ from those shown in the diagram. The main thing is to understand the principle.
For a better understanding of the operation of the pass-through switch circuit from two places without a branch box, watch the video.
Wiring diagram for pass-through switches from three places without a branch box.
The three-location circuit uses a crossover switch. It is installed between two pass-through switches, in socket 2 in the diagram.
The pass-through switch, when pressing a key, transfers the contact 1 between two others - 2 And 3 .
A crossover switch switches contacts crosswise. At one key position the contact a connected to contact c, and contact b with contact d. In the other - contact a connects with d, and contact b with contact c, i.e. criss-cross.
In this simple way you can connect pass-through switches from two, three or more places without a branch box.
In conclusion of this article, I suggest watching a video that more clearly demonstrates the operation of a pass-through switch circuit from three places without a branch box.
Subscribe to my YouTube channel and be the first to receive new electrical videos! Don't forget to click LIKE.
And finally, a list of materials on feed-through and crossover switches that I recommend studying.
Useful articles
Based on basic savings, you begin to think about how not to turn on the lights around the clock. Lighting in different rooms especially on different floors. Whether they have their own house or an apartment, everyone has the same problem. In the recent past, lights were on everywhere without turning off. How can you make a connection that will solve this problem? And there is a way out. To prevent the light from being constantly on, it is possible to control it from different places.
It is possible to turn the lamps on and off from different places. And this opportunity exists thanks to pass-through switches. They may be called “duplicate” or “reversible”. But this is all one type of equipment. They differ from ordinary ones in the large number of contacts. Therefore, connecting these switches is more complicated. And so we deal with the pass-through switch.
- How does a pass-through switch work?
- Switch connection diagram from two places
- Three point diagram
- Two-key switch: connection diagram
If we talk about the visible difference, then this is the only thing: a barely noticeable arrow on the up and down key.
It looks like a pass-through one-key switch, there are double arrows
The circuit of a pass-through switch is not so complicated: in simple switches there are only two contacts, in pass-through switches (also redundant) there are three contacts, two of which are common. There are always two or more such switches in the connection diagram; they are assembled using common wires.
Pass-through switch: difference in the number of contacts
A simple principle: changing the position of the key switches the input to one of the outputs. Pass-through switches have only two operating positions:
- input to output 1;
- input to output 2.
There are simply no other provisions. This is why it all works. Because the contact switches from one position to another, it is more correct to call them "switches". Therefore, the pass-through switch is the same device.
Even if the arrows on the keys are not visible, we disassemble the contact part. Standard products indicate a connection diagram that allows you to understand what type of equipment you have in your hands. All more or less self-respecting manufacturers have this scheme. Many Chinese do not have this scheme.
Rear changeover switch
If there is no diagram, look at the contacts (copper clips in the holes): you will find three contacts. Very often, a separate contact, especially with inexpensive manufacturers, is the input. They are often confused. To determine the general contact, you just need to ring at different positions of the key. This must be done in any case, otherwise it may not work, and the switch itself may burn out.
Using a tester or multimeter, we determine which of these three is common.
After watching this video you will understand how to find the input (common contact) for a pass-through switch.
Such a connection will be needed on the stairs of a two-story house or in a long corridor. You can also use it even in the bedroom - turn off the overhead lights at the entrance and near the bed (remember how many times you suffered with this)
A pass-through switch is a connection system where zero and ground (if any) are supplied directly to the lamp. The phase is connected to the output of the first switch, the input of the second is connected to the free wire of the lamp, the outputs of the two switches are connected to each other.
Looking at the diagram, it is immediately clear how the pass-through switch works. The lamp in the picture is in the on position. When you press a key on any of the devices, the circuit breaks. Also, in the off position, by pressing the key, we will close the circuit through one of the jumpers and the lamp will light up. pass-through switch connection diagram
For clarity, here are a few examples.
Switch diagram
Speaking about the premises, the wiring needs to be done starting from the electrical panel with automatic machines and and continuing as shown in the photo below. According to the rules, they should be located at a distance of 15 cm from the ceiling. They can be laid both in corrugations and boxes; wires are inserted into installation boxes. For the convenience of possible wire replacement. According to the latest standards, all connections are made only using contactors in junction boxes. When using twists, they need to be soldered and well insulated.
We connect the return wire of the lamp to the output of the second switch. White indicates the wires connecting the outputs of both devices.
Wiring around the premises
How to connect everything in the terminal box is described in the video.
to 3 points
To adjust the switch from three places, add a cross (cross) switch to two switches. It differs from those previously described by the presence of two inputs and two outputs. He switches a couple of contacts at once. See the figure for the connection diagram. If you understand what was above, understanding this one will not be difficult. pass-through switch connection diagram
- Zero (and ground, if any) is connected directly to the lamp.
- The phase is connected to the input of one of the pass-through switches (with three inputs).
- The input of the second is fed to the free wire of the lamp.
- The two outputs of one three-contact device are connected to the input of a crossover switch (with four inputs).
- The two outputs of the second three-contact device are connected to the second pair of switch contacts with four inputs.
The same diagram, but from a different perspective - where to connect the wires on the housings.
Where to connect the wires
And this is approximately how to distribute it around the room.
If a circuit with four, five or more points is needed, then the only difference is the number of cross switches (for four inputs/outputs). There are always two switches (with three inputs/outputs) - at the beginning and at the end of the circuit. All others are cross switches.
Connections of pass-through switches for 5 points
If you remove one crossbar, you get a four-point control scheme. Add more - there will already be a circuit for 6 control points. pass-through switch connection diagram
Also watch this video.
Connection diagram for pass-through switch two keyboards
To control two or more lamps (or a group of lamps) from several places, it is necessary to use two-key pass-through switches. The two rocker switches have six contacts. You can find common wires using the same principle as in a conventional device of this type, only the number of wires will increase.
The switching circuit of a 2-key pass-through switch is distinguished by a large number of wires: the phase is supplied to both inputs of the first switch, just as from the two inputs of the second it must go to two lamps (or two groups of lamps, if we are talking about a multi-arm chandelier).
The principle of connecting two-key pass-through switches
To organize control of two or more light sources from three or more points, you will have to install two cross switches at each point: there are simply no two-key switches. In this case, one pair of contacts is placed on one crossbar, the second on the other. And later they are connected to each other. The outputs of both crossbars are connected to the two-key transition switch, which is the last one in the circuit.
Information to note: ,