How to connect a switch with one key: rules and connection diagrams

To control household electrical lighting sources, various devices are used, the most common among all is the switch. This is a simple device, placed on the wall and connected with wires. The design of the products is different, but the internal circuit diagram of the single models is the same. Let's try to figure out how to connect a switch with one key in order to quickly make repairs.

A switch is a simple mechanical (rarely electronic) device for contact closing / opening of an electrical circuit in order to turn on / off lighting fixtures.

We will touch on the design features and installation of the simplest models - single-gang switches. They consist of 4 main parts:

• working unit (metal base with contacts and push-button drive);
• fasteners (legs or antennae made of metal connected to a metal plate);
• decorative design (panels or frames);
• dynamic part - a plastic key.

Part of the parts, mainly internal, is made of metal (for example, galvanized steel), external decorative trim is usually made of safe plastic. Ceramic elements are also possible, withstanding loads up to 32 A, while plastic is rated for 16 A.

The design of a simple switch with one key: 1 - a key with which the mechanism is activated; 2 - decorative frame; 3 - the working part, which contains the electrical mechanism

The external and internal structure depends on several factors, for example, functional tasks or potential load. As an additional device, some models have an LED that provides external illumination.

Switches are installed in all rooms where there are any lighting devices that are not equipped with a power cable (for example, it is not needed for floor lamps or table lamps). These are most often ceiling or wall lamps, chandeliers, complex lighting systems.

When choosing devices for rooms with a high level of humidity, you should pay attention to such an indicator as the level of protection: for a bedroom or living room, IP 20 is enough, for a bathroom or kitchen - IP 40, for outdoor (street) installation - IP 55

Types of devices for domestic use

There is no strict division into categories, since different manufacturers have their own, “branded” model ranges, however, several large categories can be distinguished, united by some one sign.

The two most common types of modern switches are the single-button wall-mounted model and the control panel, which is usually supplied with the lighting fixture.

For example, according to the principle of inclusion, all devices can be divided into:

• mechanical - elementary keyboard devices, easy to install and use (the function of a key can be performed by a lever, toggle switch, button, cord, rotary knob);
• electronic touch, actuated by the touch of a hand;
• with remote control, equipped with a remote control or motion sensor.

The first group is considered the most popular, traditional and recognized from the first days of the invention of the electric circuit, the popularity of the third is also gaining momentum, and the second somehow did not take root. Motion sensors save energy and serve as additional protection. For example, if you install a similar device at the entrance to the house, it will signal the appearance of uninvited guests.

In residential premises, it is preferable to install internal models (with or without lighting) that do not protrude above the wall surface and look more aesthetically pleasing.

According to the type of construction, all switches are divided into single-key and multi-key (standard version for domestic use - with 2-3 keys). Each key is used to close / open one lighting circuit. If there are several lighting fixtures in the room - a chandelier, a ceiling light and a sconce - a three-gang switch is appropriate.

According to the method of installation, two groups can be distinguished: with external and internal installation. The external type is usually used when the wiring is open, and the internal type is used with cables sewn into the wall. To ensure the safety and stability of the installation of the built-in switch, use a mounting box (socket box) - a protective plastic case.

According to the installation method, the switches are divided into built-in and overhead. The former are used for closed wiring, the latter for open wiring. Both options are installed in the same way.

Location: convenience and safety

Before installing the switch, you should consider the most convenient place for installation and subsequent use. The most beneficial area is located near the entrance doors (from the side of the door handle), but there may be exceptions (for example, next to the head of the bed).

Before drawing up a wiring project, it is better to look at the official document - PUE (electrical installation rules), which regulates some of the nuances of installation. For example, paragraph 7.1.48 states that the switch must be located at least 60 cm from the shower cabin, and paragraph 7.1.50 allows it to be installed no closer than 50 cm from the gas pipeline.

As can be seen from the installation diagram, the distance from the doors to the installation point must be at least 10 cm, and from the floor - at least 90 cm.

In bathrooms and saunas, the installation of control devices is prohibited, they must be taken out of the room (usually into the corridor).

Three options for mounting single-gang switches

Consider three circuits for connecting switches that are similar in design (have one key), but differ in the type of installation. Also, all options are united by the basic law of the introduction of single-key models: the dynamic element opens the “phase”, and not “zero”. Otherwise, there is a risk of injury when carrying out repairs and even when simply replacing lamps.

How to install an outdoor type device: detailed photo instruction

The location of the wires for this connection scheme does not matter: they can go along the surface or be inside the wall. An outdoor type of switch in a residential area is welcome if an expensive repair has just been made and there is no desire to re-destroy walls and run channels.

The simplest single-key switch connection diagram, which serves as the basis for the practical actions of novice electricians: the L (phase) wire goes to the switch, the rest go directly to the light source

We will consider an option with external cable laying, in which the wires are enclosed in a corrugated protective channel.

At the place of installation of the switch, the corrugated pipe, fixed on the wall with special clips, is cut open, and the working insulated wire is pulled out

Under the switch there will be another electrical device - a socket, therefore, for aesthetic reasons, the cables for both devices are enclosed in one corrugation.

The power cable associated with the socket will pass through the surface switch, so as not to create a loop and increase the installation area

The selected switch model - Schneider Electric - has a plastic case and an IP44 degree of protection. Before installation, we take security measures: turn off the power to the cable at the electrical panel installed on the site or in the corridor.

To make sure that there is no voltage in the cable, use an indicator screwdriver. When the issue of power outage is resolved, we take up the disassembly of the switch. First, we take out the key with our hand - this is done quite easily.

Under the key that closes the switch from above, there is another plastic protective strip - the front panel, which must also be removed by gently wringing out the holders

The next step is to remove the working mechanism.

The mechanism that closes / opens the electrical circuit is not fixed with special holders or springs, so it can be removed quickly and without problems

Now you need to accurately determine the installation location of the switch and mark the points on the wall for screwing in the fasteners. To do this, we take an already empty case and apply it to the wall. Align by level, mark the points for drilling with a marker. Using a drill, we drill holes for fasteners (another method of fastening is also possible).

We fix the plastic case in the designated place on the wall using dowels - the best option for fixing on concrete and brick bases

We remove the elastic plug located in the upper part from the switch body, insert the wires and the end of the corrugated pipe coming from the ceiling into the hole.

The result should be a neat tight connection of the corrugations with the body with free access to the wires for further work.

Time to get straight to the connection. Remove the insulating material from the ends of the wires, clean 8-10 mm. We connect the white wire (phase) to the terminal with the designation L, blue - to the other terminal, with the designation "1". We carefully tighten the bolts and place the working unit in the housing.

We lay the wire leading to the outlet into the bypass of the working unit and bring it out into the lower opening of the housing, insert the second end of the corrugated pipe there

We reassemble the switch: put the front panel in place, then fix the key.

At the end of the work, we perform testing: turn on the power supply and press the key several times. If the lighting device lights up when turned on, the connection is made correctly

Installing the switch with your own hands is quite easy, even if the installation is complicated by the presence of additional devices. However, if you are not sure of the correctness of the actions, it is better to play it safe and make the first connection under the supervision of an experienced electrician.

Master class on replacing an old switch

Often, in connection with repairs in an apartment or a private house, it is necessary to dismantle the old switch and install a new, more modern and convenient one in its place. Consider the main stages of replacement, using step-by-step photos of the process.

Before us is an old, ugly model of a built-in switch, installed inside the concrete base of a panel house. It must be removed by unscrewing the two fixing screws.

Using a screwdriver, unscrew the screws, remove the plastic cover.

Under the cover there is an old connection mechanism in which the wires are bolted. Bolts are visible on the left, on both sides - metal mounting "lugs"

Our task is to determine the "phase".

To find the working wire, we use a voltage indicator, which is usually an indicator screwdriver with a light signal

We alternately bring the screwdriver to the contacts, in no case touching them with our hands (it is better to use insulating gloves). For an accurate definition, set the key to both positions. When the "phase" position is off, only one contact will be powered. The second wire is for the lighting fixture.

Having established the purpose of the wires, we turn off the electricity supply, check the presence or absence of voltage and, making sure that it is safe, we begin to disassemble the old switch. We unscrew the fasteners of the metal holders (“legs”), we take out the working unit.

Carefully disconnect and isolate the wires: first the “phase”, then the second wire. For insulation, it is better to use electrical tape of different colors so as not to make a mistake when connecting

We finally release the mechanism, straighten the wires - the place for the new switch is prepared. We take a new product purchased in advance and prepare it for installation, in other words, we disassemble it. We remove the key, unscrew the protective panel and see the internal mechanism - with two obligatory clamps and spacer holders.

The screws located at the edges regulate the movement of the “legs”, and those located on top serve to connect wires - they are the ones that regulate the contact pressure plate

We clean the ends of the wires by about 1 cm, insert them into the holes located under the upper screws, make sure that the winding does not slip inside together with the bare wire. Tighten tightly so that the wires do not move.

If the holes are marked, we insert the “phase” into the hole marked “L”, the outlet wire is “1”. Instead of the indicated designations, there may be numbers "1" and "2" - then the "phase" will go to "1"

After connecting the wires, insert the working unit into the mounting box.

So that the mechanism does not “walk” inside the socket box, we fix it with metal holders, tightly tightening the side mounting screws

We install the top panel, fix the key.

We test the operation of the device, although the first check is best done even before the internal mechanism is fully fixed - so that you do not have to redo

So, to install a new switch, we needed tools (screwdriver, pliers, knife, wire cutters, indicator screwdriver), some insulating material and 20 minutes of time. Calling an electrician would cost about 500 rubles.

Wiring diagram with junction box

When you get bare walls (which is found in new modern standard houses), you have to insert interior doors on your own, lay floors, and put the walls in order.

Electrical wiring is no exception. Therefore, we will consider how to properly connect the switch together with the lighting fixture, circuit breaker and junction box.

You need to start by choosing a connection scheme. In the figure - the simplest, with one source of illumination, a single-gang switch and an exit to the shield, we will complicate it by installing automation

Our goal is to install all devices in the places designated for them and connect them with wires without confusing them. We try to install the junction box in the center. An open or closed method of cable installation does not fundamentally affect the arrangement of circuit elements.

As a result of pre-installation, the following scheme should be obtained: automatic unit + junction box + mounting box for the switch + exit to the lamp + three-core cable with a cross section of 1.5

First of all, we connect an automatic protection device that protects the network from overloads and power surges. Decide on the color of the wires:

• white - "phase";
• blue - "zero";
• yellow is earth.

We clean the wires and insert them into the terminals intended for them. We use the yellow wire for grounding, fixing it separately with a special clamp.

The role of the lamp will be played by an ordinary cartridge and a light bulb (incandescent, LED, energy-saving).

We clean the wires and connect them to the cartridge, inserting them into the holes intended for this. The yellow wire is carefully bent and insulated

We bring the wires into the mounting box to install the switch.

When connecting the switch, the yellow wire is also not useful. We clean the other two, isolate the yellow and bend it to the side

Modern models of switches have marked terminals, which makes it easier to fix the wiring. We insert them into the desired holes and fix them with screws.

After connecting the wires to the switch mechanism, we insert the working unit into the mounting box, put the case on top, fix the key

All elements of the circuit are connected, it remains to connect the wires in the junction box.

We remove the insulation, clean the ends of the wires, twist them first with our hands, then with pliers. We make a connection by color according to the picture, remove uneven tips with wire cutters

We check the correctness of the connections with an indicator screwdriver and test - we press the switch key.

If the light turns on and off under the control of the switch, all steps have been completed correctly. Turn off the power, hide the wires and close the junction box

As you can see, the entire connection scheme can be done independently using a minimum of simple tools.

Videos with connection examples

Useful video instructions will help novice electricians learn the theory and apply it correctly in practice.

Instructions from the manufacturer legrand:

Mounting the switch and socket:

Do-it-yourself switch replacement:

As you have noticed, the principles of connecting various electrical devices are similar, but have slight differences. Having decided to replace the switch yourself or lay the entire electrical circuit, carefully study the diagrams, consult qualified specialists, and be sure to follow safety precautions during work.