Rules for connecting two lighting lamps to one switch

Often a situation arises when it is necessary for the light bulbs in one of the rooms to be turned on from different places. For such cases, on flights of stairs there are pass-through switches, which are difficult to install, so it is usually impractical to install such switches in apartments.

It is much easier to turn on several light bulbs from one regular switch. How to connect two light bulbs to one switch will be discussed in this article.

Serial and parallel connection of two or more light sources

In order to connect the simplest incandescent light bulb, as in principle any other, you need to connect one contact to phase and the other to zero, the most common alternating voltage in the CIS countries, 220 volts.

Parallel connection of lighting devices means connecting two or more sources of light flux in parallel, that is, some lamp contacts are connected only to phase, and all others only to zero, as shown in Figure 1.

A current will pass through each light bulb, which will depend on its power, just as the brightness of the light flux emitted by them will also depend on the power of each lamp. Naturally, the current I will be equal to the sum of all three currents, so the cross-sectional diameter of the main conductors should be chosen according to it. This connection is considered the most common and acceptable, since it will be possible, if necessary, to add light sources in the future and they will not affect those already installed.

With a series connection shown in the figure, the current flowing through one light bulb will depend on the power of each light source, and the voltage on them will be divided by the number of lamps and, for a given input voltage of 220 volts, will be equal to 110 volts on each light source.

This connection must be made with lamps that have equal power. This can be seen using the example of two incandescent lamps. Since if you connect one lamp of 20 Watt, and another, for example, of 200 Watt, then the lamp with a lower power will immediately fail, since the same current will pass through it as in the second lamp with a power of 200 Watt, and this is 10 times its face value. This connection can be used to increase the service life of incandescent lamps, for example, in entrances and staircases. By connecting two lamps of 220 volts and a power of, for example, 60 watts each, they will burn at half power and will last a very long time. Please note that this is only possible when connecting incandescent lamps. Connecting two or more LED lamps (luminaires) and energy-efficient lamps in series is not practical, since they already have a fairly long service life.

Connecting a lamp to one switch or several

How to connect a lamp through a switch? The main nuance when connecting is that the neutral power wire is directly connected to the 220 volt network, and the phase is broken through the switch. This is done so that you can safely solve problems with the lamp socket by turning off only the switch. If two switches are connected in series, then only when both keys are pressed will the lamp light up. These types of connection of light switches are very rarely used, only under certain individual conditions.

More interesting is the connection of the so-called pass-through switch.

The essence of this circuit for connecting one lamp is that the lamp can be turned on and off from both the first and second switches, regardless of the position of each of them. For example, this is convenient, say, in a long corridor, when entering it, a person presses the switch key 2, and calmly walks along the illuminated room, having reached the end of the corridor, there is no need to return to turn off the light, but he can lightly press switch 1, installed at the end corridor, turn off this light source. With this connection, the phase also passes through the switches.

Improving lighting by installing a motion sensor

The main function of installing a motion sensor and connecting it to the lighting system is to automatically turn on the lighting without pressing the light switch button. That is, a person entered the room or into the sensor trigger zone and the light turned on; after leaving, the light turned off on its own (automatically). When choosing a motion sensor, you must first take into account the maximum power of the lighting lamps.

The connection diagram for the motion sensor is also not particularly difficult. It can be installed with or without a switch. Simply, when the switch contact is turned on, the motion sensor is removed from the lighting network, and the lighting device is turned on directly without a sensor.

In any case, when working with voltage, be sure to comply with safety requirements, and in particular:

• check the presence and absence of voltage on live elements that a person touches during installation;
• lighting power supply circuit breakers must be locked;
• carry out work with proper tools.

Primary requirements

The most important requirements when working with electrical wiring are compliance with safety rules and rules for installing electrical devices. There is no point in studying the “bible” of electricians: “Rules for the safe operation of consumer electrical installations” (RBEEP) and “Rules for the construction of electrical installations” (RUE). Such documentation is necessary mainly for those people for whom working with electricity is their main activity. For home repairs, to connect a chandelier with a switch, it is enough to know and follow simple rules.

Rule 1. All tools that will be used to perform work on electrical wiring must have high-quality insulation of the handles.

Tool set with insulated handles

• Rule 2. Most work should be performed only on de-energized wires. It is not enough to flip the light switch. To completely cut off the power, there is a main switch on the apartment panel, which must be turned off before starting work.
• Rule 3. The light switch is mounted exclusively in the break of the phase wire.

Correct connection of the switchThe switch is mounted in the phase wire break

Wiring diagram for a chandelier with a double switch

As can be seen from the figure, there are three wires suitable for the double switch, one of which comes from the junction box, and the other two are used to connect the lamp. Therefore, when installing new wiring, you need to use a cable with 3 wires.

Connecting a chandelier to a double switch follows the same rules as connecting a regular lamp.

What are the risks of polarity reversal?

Quite often you can hear from non-professional advisers that the switch can be installed on any wire. Like, what difference does it make, because when the contacts are open, no current flows through the lamp and that’s enough. This is wrong. The fact is that if the switch breaks the neutral conductor, then no current will flow through the chandelier lamps, but there will be a phase potential on all wires, which threatens an electric shock during work.

A less dangerous, but unpleasant feature of such switching is that fluorescent lamps and “housekeeper” lamps can glow faintly or flicker even in the off position.

Tool

To connect a chandelier or other lamp you will need the following:

• Straight and Phillips screwdrivers;
• Side cutters;
• Pliers;
• Sharp knife;
• Measuring instrument, digital or pointer;
• Indicator screwdriver (probe);
• Insulating tape.

The purpose of most tools is clear without comment. Why do you need a knife? In some cases, namely when removing insulation from single-core conductors of an electric cable, side cutters or pliers cannot be used, since a transverse cut of the core on the connected wire will lead to its fracture. This is especially true for aluminum wires.

The insulation must be cut with a sharp knife, similar to how a pencil is sharpened. Longitudinal scratches on wire strands are not dangerous.

The indicator screwdriver is used to search for the phase conductor. And although its end provides the possibility of using it as a screwdriver, this is not necessary, since the mechanical strength of the indicator is very low and it is almost impossible to tighten the screw normally without breaking the tool (it is possible, but the tool will not last long).

Indicator screwdriver - the main tool of an electrician

You should dwell in more detail on measuring instruments. They are digital and pointer. For most parameters, digital is preferable. They have high accuracy, are not afraid of shocks and falls from a height, and are protected from overload.

The pointer device should be used only in the position for which it is intended (most portable devices should be placed horizontally); a fall from a height will with a 100% probability disable it, as will overload if the regulator is incorrectly set. The undoubted advantage of a pointer device is that voltage measurements can be made without a built-in power source.

Inexpensive pointer and digital testers made in China

Note for all types of devices: the operating range must provide for measuring an alternating voltage of at least 500 V.

Application of junction box

Cables and wires do not go directly from the panel to electrical appliances, from switches to light bulbs. All outgoing and incoming lines of electrical equipment are found in specific installation units called branch boxes. There they communicate in a certain way.

The following article will introduce you to the rules for installing junction boxes, also called junction boxes, branch boxes, or in electricians' slang, junction boxes. We recommend that you read the useful material.

Most often, boxes have empty space inside. The wires of different lines are then connected to each other using twists. To ensure reliability, it is recommended to treat the tails of the connections with special welding. Copper conductors can simply be soldered.

Before laying inside, open contacts are insulated from each other with cotton tape. You can screw special insulating clamps onto the twisted wires. Here, insulating tape is no longer needed.

If the box is equipped with screw terminals, the contacts are then made using them. Such devices allow you to connect aluminum and copper conductors. Clamp terminals can be used, but this is only if there is sufficient space for laying the ends of the wires connected by them.

Installation Safety Precautions

Here is a set of some standard rules to avoid trouble when installing lighting fixtures:

1. The switch cannot be set to “zero”; it must always break the “phase”. Only in this case the switch is in the “off” position. allows you to carry out any repair work on the lamp, including replacing it, without cutting off power to the entire house.
2. When making a twisted connection of wires in a junction box, under no circumstances should aluminum and copper wires be connected to each other. Metals with different potentials form a galvanic couple; the contact will weaken over time and begin to “spark.” Sometimes this leads to fires.
3. Before starting work, you should stock up on a tester to determine the phase wire and, just in case, thick rubber gloves.
4. You should not cover open wiring (either double insulated or triple insulated, it doesn’t matter) with paper wallpaper or other flammable finishing materials.
5. Do not use used wiring. It is unknown what loads it was subjected to in the past, and it is impossible to check the condition of each core inside the braid along its entire length.

How to wire

The laying of wires is carried out at the stage of forming the base of the ceiling. They are secured so that there is no tension or excessive sagging. To install the wiring yourself, you need to adhere to the following algorithm:

• A distribution box needs to be installed. It should not be located behind the ceiling trim. There must be access to it.
• A corrugated cable line is laid from the box to all installation locations of the lighting device.
• If halogen devices are used, all transformers are connected with a separate wire. In the electrical circuit, halogen bulbs should be connected in parallel to each other, and the switch should go to the transformer on the 220V side. To connect the wires in the transformer, terminals N and L are provided.
• After fixing the wires, the lamps begin to be installed.

Transmitter connection option

Instead of connecting two light bulbs to a 220 V network, you can connect lighting fixtures to the network using 12 V frequency converters. Such devices conduct electric current to several lamps with a short pause of 1-2 seconds. At the same time, lighting devices receive electricity smoothly, without a sharp increase in load.

When can you connect the converter:

• for supplying current to incandescent lamps;
• for providing electricity to halogen light bulbs.

The switch is installed in the circuit before the converter. Otherwise, the contacts may burn out. This should happen because the current is greater at low voltage. In addition, the converter provides a slight delay in the incoming voltage. If a breaker is added after the switch, then the gradual, smooth start of the light bulbs will not be ensured. Thus, the whole point of including the converter in the circuit is lost.

If a two-key switch is mounted, then you will need to connect 2 converters. Power will have to be supplied to it through a second line. “Zero” will remain common.

Serial connection

You can connect spotlights in series, although this is not the best solution. Despite the fact that this type of connection requires a minimum number of wires, it is practically not used in everyday life. This is because it has two significant drawbacks:

1. The lamps do not glow at full strength because they are supplied with reduced voltage. How much reduced depends on the number of connected light bulbs. For example, if three lamps are connected to 220 V, you need to divide by 3. This means that each lamp receives 73 V. If 5 lamps are connected, divide by 5, etc.

Series connection principle

It is for these reasons that this type of connection is used exclusively in Christmas tree garlands, where a large number of low-power light sources are collected. You can, of course, use the first disadvantage: connect 18 or 19 12 V light bulbs in series to a 220 V network. In total they will give 220 V (with 18 pieces 216 V, with 19 - 228 V). In this case, you don’t need a transformer, which is a plus. But if one of them burns out (or even the contact deteriorates), it will take a long time to find the cause. And this is a big minus that negates all the positive aspects.

Diagram of serial connection of light bulbs (spotlights)

If you decide to connect spotlights in series, this is easy to do: the phase bypasses all the lamps one after another, zero is supplied to the second contact of the last bulb in the chain.

If we talk about the actual implementation, then the phase from the distribution box is supplied to the switch, from there to the first spotlight, from its second contact to the next... and so on until the end of the chain. The neutral wire is connected to the second contact of the last lamp.

Diagram of sequential connection of spotlights via a single-key switch

This scheme has one practical application - in the entrances of houses. You can connect two incandescent light bulbs in parallel to a regular 220 V network. They will glow incandescently, but will burn out extremely rarely.

Installation instructions

Installation of switches is carried out in several stages. Each of them has its own characteristics.

Preparing the walls

Cable products can be laid in an open or closed way. The execution of this step depends on the type of wiring selected.

If an open method is chosen, it is necessary to determine the mounting locations for distribution boxes, sockets and switches (installation platforms must be mounted at this location), and outline cable routes. The cable can be attached:

• on plastic brackets;
• on supports (wiring in “Retro” style).

It is also possible to lay conductor products in cable channels.

Fastening cables to the wall with plastic brackets.

Open wiring on insulating posts.

If hidden wiring is chosen, then, after determining the installation locations for electrical appliances, channels (grooves) must be made in the walls for laying cables and recesses for installing plastic boxes. After laying the conductor products and bringing the wires out into the distribution boxes and socket boxes, the grooves are plastered and work on the interior arrangement is carried out.

Wall chipping is the most difficult stage.

Connections in the distribution box

The wires leading into the junction box must be prepared - shortened, removed the overall sheath and stripped the ends by 1-1.5 cm. This can be done using a repair knife.

Conductors in the junction box, ready for connection.

Next, you need to connect the conductors according to the selected diagram. The cores can be connected by twisting (preferably followed by soldering). After this, the ends must be insulated. You can also use modern clamp terminals.

Switch installation

Installation of a switch, regardless of its design (surface or internal), also begins with shortening and cutting the cable.

Preparing the wires.

Then the switch must be partially disassembled - remove the keys and decorative frame. The next step is to connect the wires to the switch terminals. The screws in the clamp terminals must be tightened securely. The spring ones will clamp the wire themselves.

Connecting conductors to terminals.

Then the switch is installed in place, fastened according to the design, and decorative plastic parts are installed.

Switch installation procedure.

Connecting two lamps

There are only two options for connecting light bulbs to one switch:

• sequential;
• parallel.

When mounted in series, the lamps are connected to each other by wire, and the power cable is connected to the remaining free terminals - as in the diagram. In some cases, phasing may be required. Then a phase conductor is connected to the L input of one lamp, the N input is connected to the L input of another lamp, and the neutral wire is connected to the remaining free terminal N of the second lamp.

Diagram of series connection of lamps.

If it is necessary to connect two lamps in parallel, then conductors L and N are connected to the terminals of the first lamp, and the second section of cable is connected to the same terminals, forming a loop. The second end of the cable is connected to terminals L and N of the second lamp, etc.

Diagram of parallel connection of lamps.

It will be useful to read: How to connect light bulbs in series and parallel

Other schemes

Sometimes there is a need to connect 3 light bulbs to a two-key switch. In this case, the circuit provides that two lamps will be powered from one key, and a third from the other.

The peculiarity here is not only that everything is connected in the junction box, you also need to connect the light bulbs correctly.

In general, the connection diagram for three lamps does not differ from that described above (all connections in the junction box are the same as when connecting two lamps to a two-button switch).

The only thing is that one of the created branches will have to be divided between two lamps.

That is, each of the two cartridges will have to be connected to a phase and neutral conductor. How to do this is shown in the diagram.

The same feature applies to the circuit for connecting two lamps to a single-key breaker.

That is, the whole feature of creating a branch comes down to making a phase and zero connection to two cartridges.

It is not necessary that there be one or two lamps connected to one key. Below are several connection diagrams that assume the presence of 3-5 lamps.

The first of them is with a single-key switch:

The second scheme is with a two-key switch and a large number of lamps:

Read here: How to properly install electrical wiring.

As you can see, all the diagrams are similar to each other, so making the lighting connections correctly should not be difficult. But the main thing is compliance with safety regulations.

Switch device

The main element of the switch is the working part, mounted in the socket box. It is a metal structure with an attached drive. The drive is used to turn the device on and off. The drive is a moving contact that closes and opens an electrical circuit between two static contacts.

The first contact is called incoming: it is connected to a phase from the mains. The second contact (outgoing) is connected to the phase conductor coming from the lighting device. When the switch is positioned correctly, both fixed contacts are initially in an open state. When you press the device button, the moving contact provokes the closure of both fixed contacts. As a result, current flows through the closed circuit of their electrical network to the light bulb, and it lights up.

To ensure safety, the working part of the switch is housed in a housing made of dielectric material. The cases are made of plastic or porcelain.

Other components of the switch are the frame and keys. These elements are usually made from plastic. The keys are fixed on the drive of the working part. Moving as a result of pressing, the key changes the position of the contact, which leads to turning the light on or off.

The frame is designed to prevent a person from accidentally touching the switch contacts. In other words, the frame acts as a barrier between the energized elements and the person. The frame is fixed with screws or latches made of plastic.

The only difference between a two-key device and a single-key device is the presence of a pair of output contacts. Each contact is connected to a phase conductor of one of the lamps.

Separate lighting

A similar scheme is often used in office buildings, where it is necessary to separately illuminate many local areas. The separate lighting scheme is not particularly complicated, although it requires special knowledge.

The switch is placed in a phase break. The devices are equipped with one input and two output voltage contacts. The phase wires after the switch go to the lighting fixtures. The neutral conductor will be common to all light sources in the room.

As a result, pressing one of the keys turns on only the devices connected to a specific phase. Other light sources do not turn on.

Scheme with a two-key switch

Before connecting the wires into the circuit, you must have the following installed:

Two lamps for one bulb. For example, one in the kitchen, the second in the hallway. Distribution box under the ceiling (15-30 cm below the ceiling level). If the room already has a distribution box, you can use it. The main thing is that there is not a lot of switching and that it is convenient for you to work. Socket box for two-button switch. As a rule, it is installed at a distance of 90-100 cm from the floor level. Wires must be laid in grooves between all these elements

Please note that in the case of a two-key switch, a three-wire wire must be connected to it from the distribution box.

Now we need to connect all this electrically so that voltage comes from the power source to the light bulbs.

Two strands of wire from the supply network come into the distribution box - zero and phase. Using an indicator screwdriver, identify the phase conductor. Touch both wires one by one with a screwdriver. If you touch zero, the indicator window will not light up. If the window lights up, it means you have found a phase conductor. Carefully mark it with insulating tape.

Now to make connections, turn off the power to your workplace. You need to turn off the circuit breaker that supplies voltage. Nowadays, in many houses and apartments, entire panels are installed, in which there are circuit breakers that turn off each room. If you don’t have one yet, then you’ll have to turn off the water machine for your apartment. Check that there is no voltage and get to work.

Three strands of wire are inserted into the socket box. Strip off the insulating layer on them by 1 cm (this is done with a knife). Connect one core to the incoming contact of the switch, connect its second end in the distribution box to the phase wire of the power supply network. Connect the other two wires to the two output contacts of the switch. Accordingly, connect their second ends in a distribution box with phase conductors from one and the second lamp.

Now you can place the working part of the switch in the socket box, fix it, install the protective frame and keys.

There will be one more connection in the distribution box; connect the neutral conductors coming from the lamps to the neutral from the supply network.

The lamp sockets have two contacts - one side for connecting the neutral conductor, and a central one, the phase is connected to it. Make these connections.

Check that all contacts are reliable, but we advise you to insulate the twisted areas after you are sure that the switch is working correctly. To check the assembled circuit, apply voltage to the apartment (that is, turn on the input circuit breaker). Both keys of your switching device are in the off position, the lights in the kitchen and in the corridor are not lit. Press one key - the light in the kitchen comes on, turn on the second - light appears in the corridor. Also, turn off the first and second keys one by one, the lights went out first in the kitchen, then in the hallway. Everything works correctly.

Turn off the input circuit breaker again and insulate the places of twists in the distribution box with insulating tape; you can also put PVC tubes on top.

The circuit with a double switch is discussed in detail in this video:

Preparatory work

No matter how many keys your switch has (one, two or three), the preparatory work will be the same.

To begin with, you need to install a general distribution box and a mounting box for the switching device in the room; it is also called a socket box:

• If the walls in your room are made of PVC, plasterboard sheets, wood or MDF panels, install a special bit with serrated edges on a drill and make a hole. Insert the mounting box into it and fix it to the wall using self-tapping screws.
• For concrete or brick walls, make a hole using a hammer drill or drill with an attachment that works on concrete surfaces. But in this case, the mounting boxes must also be fixed using gypsum or alabaster mortar

As a rule, the installation of holes is carried out simultaneously with the laying of grooves. This is done purely for aesthetic reasons; there is a lot of dirt from such construction work, and it’s better to spray it once and clean it up. Grooves are grooves in the wall surface into which connecting wires will then be laid. They can be done using various tools:

• Hammer and chisel. This is an old ancestral method, its advantage is the complete absence of costs for purchasing tools (every man has a hammer and chisel). The disadvantage of this method of gating is that it takes a lot of time and effort.
• Bulgarian. This tool is often called the worst of the best. It’s convenient that grooves can be made quickly and without much effort. But it is from the grinder that there is a lot of noise and dust, and besides, it is not possible to make grooves of the same depth along the entire length, and it is almost impossible to work with the grinder in the corners of the room. So choose such a power tool as a last resort.
• Hammer. All you need is to purchase a special attachment for it - a strober or a spatula. In all other respects there are no shortcomings, it’s fast, convenient, the grooves are more or less even.
• Wall chaser. This is the ideal tool for this type of work. Works efficiently, safely and quickly. The grooves are smooth, there is no dust, since the wall chaser is connected to a construction vacuum cleaner. They are comfortable to work with and the tool does not make much noise. The only drawback is the high price. But there are services where you can rent a wall chaser.

Briefly about gating walls using the tools listed above is described in this video:

It is necessary to lay two-core wires into the grooves and fix them with cement or alabaster mortar.

So, the preparatory work is completed, the boxes are mounted, the wires are laid, and you can connect the light bulbs and switch.

Connection diagram of a single-key switch to a light bulb

First of all, power must be supplied to the circuit breaker. After this, the connection diagram for the switch and light bulb is carried out in stages. The wires in the cable used are usually blue and black, as well as yellow with a green stripe on it. The blue wire is used for zero, the yellow wire is for grounding, and the black wire is for phase. The colors of the wires for all connections must be observed in a certain order. The stripped wires are inserted into the contact terminals and clamped with special screws. All other nodes are connected in the same way.

When connecting the lamp, preparation is also carried out with wire. In this case, grounding is not used, but only the neutral and phase wires are used. After preparation, the wires are connected directly to the socket and to the switch. After this, the diagram takes on a finished form.

To check the functionality of the circuit, you need to screw a light bulb into the socket. Voltage is supplied to the circuit breaker, after which it turns on. The correctness of all connections is first checked by an indicator. After pressing the switch button, the light should light up, which means that the entire circuit is completed correctly.

Difference between parallel and series connection of lamps

If any light bulbs are connected in parallel to each other and, accordingly, in series with the switch, then the voltage on each of them will be equal and in this way light sources of different powers can be connected. The main condition is that the operating voltage at which they operate normally must be equal to the voltage of the power source. If in this case a step-down device with a rectification system is used, then the opening contact must disconnect the circuit in front of the converter, as shown in the figure.

In this case, it does not matter whether two or three light sources will be turned on. Most often these are halogen and LED lamps, designed for a reduced voltage of 12 or 24 Volts.

With a serial connection the situation changes dramatically. The supply voltage will be divided by the number of light bulbs, that is, if the network is 220 Volts, then on two artificial light sources connected in a series circuit, the voltage will be approximately 110 Volts. This must be taken into account when choosing and purchasing them. Another nuance with this connection is related to the power of each of them. It should be the same or as close as possible to each other, because With such a connection, the current is the same in all parts of the circuit. If one lamp is 500 W and the other is 50 W, then the lamp with the lower power, connected by one wire to each other, will still flow more current, corresponding to the most powerful load. A light bulb with less power will burn out instantly. This rule applies to all types of lamp sources, from incandescent to LED.

If you need to connect an LED light source from the network or from sockets, it often consists of a so-called driver installed inside the light bulb housing. It performs several functions at once: rectifying and reducing. These lighting devices are not intended for serial connection, only for parallel connection.

For fluorescent daylight sources, both with an electronic starting device and a starter, a series connection is most often found in raster lamps, as it allows one choke and two starters to ensure stable operation. In this case, the starter itself is selected for 127 V with the calculation of the operating voltage of a standard 220 Volt network. The switch in this circuit uses a regular single-key switch and also breaks the phase wire with its contact.

As for the parallel connection of several fluorescent lamps or compact lamps, the operation of which is based on the glow of a phosphor applied to a glass tube, then in this situation it is possible to connect any number to one switch, either single-key or two-key. The main thing is to take into account the power of all light sources, on which the current in their circuit directly depends. For any switch it is limited and indicated in the technical data sheet, on the packaging or case. If, for example, a current of 5 A is specified, then you should not exceed its value, since this will very quickly render the breaking contact itself unusable.

To fully understand the serial and parallel connection of light bulbs, we recommend watching the video:

Purpose

Despite all the variety of devices for controlling lighting (button, cord, chain, slider, dimmers, remote switches, timers), the keyboard option still remains classic. And the principle of operation is the same for all: the working mechanism has two main positions (“on”, “off”) and performs two main functions - to close the electrical circuit and apply voltage to the lighting element, to open the circuit and remove the voltage from the lamp.

A two-key switch is installed in household electrical networks with voltages up to 1000 V; the main purpose of its use is to turn chandeliers, light bulbs, and lamps on and off. The main advantage of a 2-key switch is two contact terminals at the output, to which two independent groups of lighting devices can be connected.

1. When the apartment has a separate bathroom and both rooms are located next to each other through the wall. In this case, it will be very convenient to connect a double light switch and install it just on the wall partition between the doors of both rooms. One key will turn on the lights in the bathroom, the second key will turn on the light in the toilet.
2. Connecting a two-key switch is advisable when a chandelier with five or more arms or spotlights on the ceiling is installed in a large living room or office space. It is not always necessary for all the bulbs in a chandelier to light up at once; sometimes dim light is enough. For example, you can apply voltage to only two lamps by turning on one key. The second key will remain disabled, the remaining light bulbs in the lamp will not light up, thereby saving energy. Indeed, in the case when there is a single-key switch, when it is pressed, all the lamps in the chandelier light up at once. And if you calculate how much each extra burning light bulb consumes per kilowatt, you will get a decent amount in rubles per month. Why pay extra?
3. Often a double switch for two light bulbs is used in country houses. It is best to install it in rooms located close to the exit to the street. One button turns on the light in this corridor, and the second turns on the street lamp.

Safety regulations

To ensure that no unforeseen situations arise during the installation of a two-key switch, you must try to follow basic safety precautions. They will help avoid any injuries and reduce the likelihood of device failure.

Basic safety rules:

1. Any work with electricity should only be carried out by people with sufficient knowledge and experience. Otherwise, the likelihood of any injury will increase significantly.
2. Measures to install the switch can only be carried out after turning off the power supply to the room. At the same time, care should be taken to ensure that no one accidentally turns on the electricity.
3. Before touching exposed wires, you need to check them with a special indicator screwdriver for the presence of voltage.
4. It is forbidden to touch two bare wires with your hands, even if they are disconnected from the power supply.
5. Do not touch the wires with wet hands. The same applies to other structural elements capable of conducting electric current.
6. Any preventive, installation or repair measures can only be carried out using tools equipped with insulated handles.
7. Experts recommend carefully isolating all potentially dangerous places. This simple action will help avoid accidental contact of contacts, which will cause a short circuit.
8. It is prohibited to turn on the power supply in the room until the installation work is completed.
9. Clothing and shoes should not create discomfort or distract the technician from the installation process.
10. When testing an installed switch, you should be extremely careful and remember the safety rules.

Thus, almost anyone can install a two-key switch. And provided you follow the advice of professionals and safety regulations, everything will go quickly and smoothly.

Useful tips

During the installation of the switch there are several very important points that must be remembered. Moreover, this applies not only to the installation process itself, but also to the selection of the necessary equipment. By following a few simple rules, the system will be more reliable and secure.

Below is a list of recommendations and rules that must be followed for safety reasons:

• all work on connecting equipment in the distribution panel must be carried out by qualified electricians; in the absence of knowledge and skills in this area, interfering with the security system located on the site is unacceptable;
• any actions should be carried out exclusively after a power outage at the general apartment switchboard, and before carrying out any operations with wires, you should make sure that the electrical circuit is de-energized (you can use a probe for this);
• in the case when it is planned to connect and install a contactless device or a device with a dimmer, a detailed study of the circuit is required, since the basic installation principle may differ significantly from the installation of a two-key switch, and may have many nuances.

To summarize, connecting a two-key switch to two light bulbs is quite simple, especially if you have at least some skills in this area. But if you have no experience working with electrical equipment, it is better to leave this matter in the hands of professionals. Remember that working with electrical power can be life-threatening. Improperly installed wiring may cause a short circuit and fire. Don't risk your life and contact specialists!

Two lamps per switch

Connection diagram for several light bulbs to a switch:

1. De-energize the system. We connect the stripped wires to the contacts carefully, in accordance with the principles outlined above.
2. The junction box receives zero and phase from the general network. The zero coming from there must pass through all the lamps. We bring it directly to the lamps, bypassing the switch.
3. The phase passed through the switch is sent to the central contacts of the bases. It comes from the network into the distribution box and passes through the input on the switch.
4. The phase is then output through the outgoing contacts on the device.
5. From there we send the phase to go through two lamps. We remove it from the switch through two separate cables.

When constructing a circuit, it is necessary to calculate the total power of the light bulbs. Each of them must be marked indicating the maximum load limit.

To securely fasten the contacts, you need to use screw or spring type terminal clamps.

You should not try to connect different types of metal together. Copper and aluminum, once twisted, will begin to oxidize. As a result, the contact will overheat and become loose.

Switch device

The working part of the switch is a thin metal frame with a drive installed on it. The frame is mounted in a socket box. A drive is an electrical contact, that is, a device on which electrically conductive wires are connected. The drive on the switch is movable, and its position determines whether the circuit is closed or open. When the circuit is closed, the electricity is on. An open circuit makes it impossible to transmit current.

The drive provides electricity or an obstacle to the path of the signal transmitted between two fixed contacts:

• the input contact goes to the phase from the electrical wiring;
• the outgoing contact is connected to the phase going to the lamp.

The normal contact position on the actuator implies that the commutator is off. The fixed contacts are open at this time and there is no lighting.

Pressing the control button on the switch completes the circuit. The moving contact changes its position, and the fixed parts become connected to each other. Along this path, the voltage network transmits electricity to the light bulb.

To ensure the safety of the system, the working part must be placed in a housing made of materials that are not capable of conducting electric current. In the switch such materials can be:

Other design elements directly protect the user:

1. The control key allows you to change the state of the circuit with one touch, closing and opening it at the request of the person. As a result of a light press, the light in the room turns on or off.
2. The frame completely insulates the contact part, which eliminates accidental touches and electric shocks. It is attached with special screws, and then sits on hidden latches.

Plastic is effectively used as the main material for their manufacture.

Safety conditions

Installation of pass-through switches is possible with both open and hidden wiring systems.

Installation can be carried out independently, only if you follow the necessary safety rules:

1. Before starting installation work, it is necessary to turn off the power to the apartment.
2. It is necessary to correctly determine the location of the phase and zero.
3. The wires should be connected by neat twisting, while crimping and insulating them.
4. It is recommended to firmly fix electrical accessories and branch boxes to surfaces.
5. Based on the power of electricity consumed, you need to determine the power parameter of the lighting device and select a three-core cable of the required cross-section.

Due to a design feature, the keys of backup electrical switches do not have a specific “on” or “off” position. Based on the position of the electrical contacts of the other switch, the two connecting nodes of this system correspond to the “closed” or “open” position. Therefore, when the light is turned off, the key will be in a different position each time. This feature is not a problem - you can quickly get used to it.

Types of lamps for home use

Tube progress keeps pace with switches. Their diversity is also impressive.

But here, too, some more popular types are defined:

1. Incandescent light bulbs are established home light sources in a round glass bulb with a vacuum and a tungsten filament inside.
2. Halogen lamps are the same incandescent lamps filled with a special gas. It increases service life and minimizes the size of their flasks. Disadvantage: When installing, you cannot touch the glass of the flask with your hands.
3. Fluorescent fluorescent lamps are not very common at home, but they are also traditional lighting devices (hereinafter simply “fluorescent lamps”).
4. Energy-saving LED lamps, as the name suggests, use the glow of groups of LEDs. They can be fixed into ordinary screw-in sockets (hereinafter simply “LED lamps”).

Energy-saving fluorescent light bulbs are increasingly replacing the usual ones. The operating principle is similar to fluorescent lamps. They are screwed in like incandescent lamps (hereinafter simply “energy-saving lamps”).

A few words about electric current

Without “loading” with theory and complex physical concepts, let us recall the elementary basics of electrics. The household electrical network has a voltage of 220 V, the type of current is alternating. What does it mean? One of the contacts, “phase,” has a constantly changing potential from “+” to “−” (50 cycles per second), and the other “zero” serves as a kind of battery, allowing electrons to either accumulate in excess or flow back.

Each lamp has two contacts: base and central. In order for our lighting device to start working, zero and phase must be connected to these two contacts. Moreover, in the case of alternating current and a regular household lamp, polarity does not play any role.

But it is still necessary to know the location of “zero” and “phase”. There is a special device - a “probe”, which is used to determine which of the wires is phase. This must be kept in mind for the correct inclusion of a disconnecting device - a switch - in the circuit. It must necessarily break the “phase”, these are the safety requirements.

Is it necessary to provide protection for pass-through switches and ground the lighting circuit?

The requirements of PUE, PTE and SNiP clearly state that lighting networks must be protected using a 6-10 Ampere “automatic machine”. Among manufacturers, it is recommended to give preference to ABB, Schneider or Eaton. Taking into account the above, it is mandatory to install a machine with optimal current in each distribution panel.

As for grounding, it is necessary to study the rules of the Electrical Installation Regulations (Chapter 1.7). The book says that the grounding of current-carrying and metal conductors to which voltage can be applied must be grounded. This means that the room must have grounding to ensure the required level of safety.

See how to choose a circuit breaker here.