Connecting the light switch. Connection of a two-button light switch

To control the operating mode of home lighting devices is a special electromechanical device - household switch. With its help, you can turn on and off the lamps connected to it in luminaires and even control the intensity of the glow.

Main characteristics

By way of installation, all household switches are divided into two types: internal and external. The first ones assume the integration of the mechanism into the wall and are designed for use in conjunction with concealed wiring. The latter are mounted directly on the wall. The need for a particular solution is determined by the features of the room and the operational requirements.

The rated voltage is no more than 1 kV (usually a traditional 220 V). The rated current is from 4 to 10 A and is determined by the design features and material of which the inner casing is made (ceramics withstand higher values than plastics). Arc chutes and protective shutdown systems are not provided. The control method is manual, although there is a special class of models controlled by an automatic twilight relay and reacting to the degree of external illumination.

By the number of switched circuits, these devices can turn one or several branches on and off. For example, the correct connection of a three-key light switch makes it possible to control three lines going to individual lamps or groups of lamps.

Depending on the implemented control mechanism switches are keyed, rotary, push-button rope and sensor.

Permissible current and power

At first glance it may seem that the connection of the light switch does not require any special knowledge, however this is not quite so. If you ignore the requirements of electrical engineering, you can not only disable the device or provoke a fire, but also get an electric shock during subsequent maintenance (lamp replacement). Thus, the correct connection of the light switch necessarily involves checking the conformity of the wiring used and the permissible current load. Let's look at this point in more detail.

Any electrical light sources are characterized, in particular, by the amount of power consumed, measured in watts. Knowing the value of the mains voltage, you can use the simplest Ohm's formula to determine the current. For example, a mercury throttle lamp per 1 kW in 220 V circuits will consume 1000 W / 220 V = 4.5 A. It is obvious that connecting a light switch designed for 4 A will lead to very unpleasant consequences. That's why it's so important to select the device in such a way that it is able to commute the circuit. In this case, you can adhere to the rule according to which the stock is not superfluous. Especially on the dimensions of the switch it does not affect in any way (one-type solutions are meant). In addition, the cross-section of the wiring leading to the luminaire must be sufficient to pass the desired current. So, the copper core is 0.5 mm square. Withstands 11 A with open wiring. It is quite understandable that if the connection of the light switch is made in such a way that it feeds through a wire a couple of kilowatt lamps, this may soon lead to a fire.

Installation and disconnection rules

The connection of the light switch can not be performed correctly without a voltage and continuity indicator. These tools allow, first of all, to protect the manufacturer of works from electric trauma. In addition, without them it is quite difficult to correctly orient the internal mechanism of the switch, because of which after installation it may well turn out that to turn on the line, it is necessary to press not the upper side of the key, but the lower one. This does not affect the operability in any way, but it is a violation of the installation requirements, and also represents a potential hazard in the subsequent maintenance of the luminaires, so in this case it is impossible to determine "by sight" the correctness of the orientation. And, finally, the connection of a two-key light switch requires an exact identification of the wires connected to it (phase or branch). This point is also important with regard to simpler devices intended for switching only one line, albeit for a slightly different reason.

Rule one: orienteering

If we talk about classical solutions that use one or more keys, then one glance at such switches is enough to understand that devices do not have top and bottom. Sometimes the body is marked, but since the outer cover is easy to unfold after disassembly, they can not be considered absolutely accurate. Although the PUE does not apply to these devices, in de-facto countries it is de facto recognized that the switched off position is the down key, the included one is up. In our opinion, this should be observed during installation. And it does not matter whether the connection of a two-key light switch or a more simplified / complicated model is performed. Imagine the following situation: the device is mounted "in reverse" and the off position corresponds to pressing the up key. The lamp burns out, the bulb comes off, and in the cartridge there is a metal base with protruding "horns". A person who knows the peculiarity of the operation of this switch is not at home and the lamp is replaced by someone from the household. Looking at the position of the keys, he concludes that the luminaire is de-energized and begins to unscrew the base. At best, there will be a short circuit through the metal of the montage, and at worst there may be very deplorable consequences for this person. If for some reason an inverted installation is still necessary, then the switch must be marked accordingly.

To determine how the switch should be oriented, you need a simple call (lamp and battery), a multimeter in the appropriate mode, or an indicator to check the circuit for integrity. Any one of these devices does an excellent job. There are two contacts inside the one- key switch . To each of them it is necessary to connect the wire from the continuity. If the internal mechanism is switched off, the warning light will not light. But it is necessary to change the position of the switch key - and the light comes on, which corresponds to the on state. Based on this measurement, further orientation and installation is carried out.

Rule two: power supply

How is the light switch connected ? The scheme is quite simple. In the device designed to switch only one line, there are two connections (clamps or bolts) to which the wires are connected: the power supply and the line that goes to the luminaire. Our household electrical systems are single-phase, that is, they use two wires - zero and phase (grounding is not taken into account). In normal operation, the hazardous potential is on the phase, so you can not touch it with your bare hands. If you touch this wire with an indicator screwdriver, the light inside it will light up, signaling the presence of the phase. Zero conductor is relatively safe.

The installation rules say that the phase conductor in the correctly aligned switch must be fed from above, and the line to the lamps is connected to the lower contact. This, again, makes it possible to secure a person if necessary for subsequent maintenance or repair, since everyone knows: if the switch is off, the outgoing line is de-energized.

But the connection scheme of the double light switch is slightly changed. In such devices there are not two, but three attachments. On the one hand, one clamp or bolt, and the other - two. The phase wire is connected to a single connection, and to the other two - along the outgoing line. This scheme of connecting a double light switch allows you to control at once two groups of lighting devices. Well, the neutral wire is disconnected directly in the luminaires. The order of the lines leaving the device is arbitrary. The connection of the double light switch is not too different from the method applicable to the conventional one-key switch.

Rule three: installation

Switches for external installation can be of two modifications: with the rear wall and without it. In its absence, the internal mechanism is closed only from the sides and from the front. Proper installation in this case involves the installation of a switch on an intermediate base. It can be cut out on dimensions of textolite, plastic or a wooden plate. Closed modifications are mounted directly on the surface.

Concealed location

Models for indoor installation are made on a different principle. Since the mechanism hides in the thickness of the wall, and only the control keys remain outside, there is no need for a dielectric enclosure. In one way or another, a notch with a diameter of at least 70 mm and a depth of about 50 mm is made, in which a special mounting box is fixed. The exact dimensions depend on the features of the switch and the nuances of installation. For example, if a gypsum board is used as a base, then boxes with a special type of fastening are used. After fixing, installation inside and further connection of the light switch are made. The scheme is similar to the above, with the only difference that you need to consider the number of switched lines.

Night "alarm"

At night, when the lighting in the room is not enough, the keys of the switch have to literally grope. And this irritation and the walls are rubbed. To solve this problem, you can connect a light switch with a backlight. In such devices, there is an LED that glows when the luminaire is de-energized with a key. Such an alarm gives a very weak glow, sufficient only to help in finding the switch. The LED is connected through a resistor in parallel to the main commutating contact.

Universal switching

Equally interesting is the connection of the light switch. This device allows you to turn on / off lighting from two or more points. For example, coming to a long corridor and pressing the key, you can light the lamps, and at the end of the path use another switch, disconnecting the line. Inside it there are three clamps: one leads to a phase wire, and lines from the other two go to the corresponding contacts of another switch. The circuits are disconnected in the junction box.

Managing without touching

But the connection of the remote light switch makes it possible to control by radio or infrared beam several light sources. Although the schemes vary significantly, the most common match is: A, B, C, D (yellow - white - green - blue) - these are lines for lamps or lamps. Blue and brown - supply 220 V. Black contact - "zero".