In electrical systems used in lighting rooms, often use two-key switches of light. This is justified by their multifunctionality. But it's not so easy to connect such a device yourself. It is necessary to know certain nuances that we will discuss in more detail.

Device, technical characteristics, operating principle

The two-button switch has in fact an uncomplicated design. It repeats the device of a similar device with one key with the only difference that inside there is not one but two mechanisms for interrupting the electric current. Accordingly, two wires from the wiring to the luminaires and one from the power supply system are connected to this switch.

Hence the principle of operation of the device described. If you press one key to "turn off then the electric current of a certain line of lamps will be interrupted, the latter will be extinguished. In this case, the remaining lamps, which are "powered" through the second plate button, remain lit. If you use both keys, then all the light in the room goes out.

This allows you to change the degree of illumination in the room. At the same time, it is possible to create a variety of luminaire lines, for example, on the principle of cascade, snake, mosaic and so on. But it is important to take into account the technical characteristics of the circuit breaker. To do this, it is enough to study its marking and look at it, how much power in kilowatts it withstands, and then add up a similar indicator of all used lamps.

Necessary materials, tools

Before starting the installation of the described device, you must carefully prepare the required arsenal for such work. Materials may require additional wires and terminal blocks (contact connectors in plastic casings, used instead of wire twisting). All this is useful if the cable, brought to the installation site of the switch, turns out to be short. So, here is the list of materials:

• wire three-core with cross-section, mm (such a parameter is standard for indoor lighting systems),
• terminal blocks,
• insulating tape.

From the tools you will need the following:

• screwdriver bayonet,
• screwdriver cross,
• screwdriver indicator,
• pliers with insulated handles,
• A stationery knife for stripping wires from insulation.

When all of the above is already at hand, we begin to work.

Preparatory Actions

The first thing to do before installing the described device, is to inspect the lead cable. If there is none, it is necessary to arrange the wiring for all lines of fixtures. Two parallel phase conductors (with insulation of brown or white color) from both lighting branches should be connected to the installation site of the two-switch switch. The corresponding zero lines with blue insulation must "go" from the lamps directly to the electrical panel, connecting at the end to a common wire.

At the same time, we should not forget that one phase wire must come from the common network to the switch. The nest of the device is usually located near the door, 10 to 20 centimeters from the clypeus, at a height of about, m from the floor. Of course, you can vary these parameters at your discretion. The main thing is that the process of turning on the light turns out to be convenient.

When the cable is already connected to the socket for fixing the described device, you need to inspect the ends of the wires and, turning off the power, clean them, that is, remove the insulation for a length of 5 - 10 mm. If it turns out that the length of the cable inserted into the beaker for setting the "recessed" switch to two keys is too short, then some of the new wires can be connected through the terminal block.

According to the electrical safety standards, the wires are always hidden in the cable, if necessary, it is shortened with using the cutters on the pliers, then it is cut to extract the ends of the wires for mounting switch. In this operation, the insulation of the "phase" or "zero" can be damaged. If this happens, you need to tear off a piece of electrical tape and wrap the damaged part of the wire.

In the case of open wiring, problems with a cable that is too short should not occur. After all, the switch is a bill of lading, it is installed directly on the wall, so its location can always be adjusted.

Connection scheme for a two-key light switch

To describe the installation of the circuit-breaker directly, it is necessary to separate two types of wiring: open and closed. After all, each option has its own nuances of connection.

It is important to remember the only absolutely identical and mandatory requirement in both cases! Always phase and only the phase wire from the circuit breaker is fed directly to the switch. And the zero wire from the common network passes through all the fixtures. This is done according to electrical safety rules, so that the power line of the electrical wiring is interrupted by a switch.

For open wiring

Here work is easy. All cables are located outside the wall. Decorative plastic boxes are installed under the color of the general covering of the room, wires are placed in them. These decorative channels can simply be glued to the wall with a double-sided rubberized tape. To hide the connections and branching of the wiring, overhead decorative plastic boxes are used.

And the double-switch itself is external. It, like boxes, is attached to the wall with the help of self-tapping screws. The latter are screwed into the dowels for which holes are pre-drilled with a perforator or a drill.

Before installation, it is necessary to disconnect the machine that supplies the phase conductor. If there are no signatures in the shield, what to go to, you must first check the cable with an indicator screwdriver, putting its sting to the corresponding end of the wire. At the same time, it is necessary to ask the assistant to alternately "click" each machine. When the indicator goes out, the desired line is determined.

Do not check the test screwdriver wire with blue insulation, and even more yellow-green, that is, a grounding line. According to the rules of electrical safety, they are never connected to the "phase".

If the wiring is not yet available, proceed as follows. The zero wire of blue color, coming from the machine from the flap, is led to the overhead decorative box. In it, we make a wiring for two lines (also with blue insulation). We take them out of the box and "feed" the planned branches of the lamps.

If there are a lot of lamps in each branch, then we do so. For a separate line, we set up our own box. In it we connect all the zero wires (blue) going in parallel from each light source. As a result, the main "zero" should leave this box in the direction of the shield.

The same is done with power wires of white or brown color. "We supply" lamps with parallel "phases which "flock" into one box. From it we derive a single phase conductor. As a result, they will be two, from each line. We lay them to the planned place of fastening of the two-button switch. Here we are submitting one phase wire from the machine.

When we have instead of a group of lamps on each line just one lamp or part of a single chandelier, the scheme is applied similar. It can be studied according to the above picture.

Next, take the switch itself. We support the keys from the side with a bayonet screwdriver, pull them out and put them aside, then remove the front of the device. At the working base on one side, on the top, on the end, there are holes for two wires coming from the illumination. And on the other hand, from the bottom, on the end - one hole for the "phase "coming" from the shield. We insert the pre-cleaned ends of the wires into these sockets and fix them.

It is necessary to know that in the modern electric goods market there are two main types of switches. In some cases, the wires are secured with the help of classical contacts with the tightening of bolts. The second type involves pinching the tip of the electrically conductive wire by means of automatic clamping. Usually, in such contact, the bare end of the wire is simply inserted, and to release it later, there is a special button or hole for pressing the mechanism with a screwdriver.

After the working base of the two-switch switch is "powered we put it to the wall and screw it. Then fix the front part with a latch or bolt, depending on the model. However, before on its end surfaces, you have to cut out the notch for the cable entry with a stationery knife. At the final stage, we insert the keys into place and turn on the machine in the shield.

For closed wiring

In the most common case, when the cables are hidden in the wall, the installation principles are somewhat different. The wiring itself is recessed into channels, which are pre-shrouded by a perforator with a special shovel or shtroborezom. The same goes for the wiring boxes. They are drowned in the wall. All the rest is already described above.

For the same boxes, as well as for the switch itself, drill in the wall with a drill and crowns over the concrete grooves. In these obtained niches insert branched nodes, and in the case of a switch - a special plastic cup, usually it is red. The latter is fixed with gypsum. The two-key switch is mounted in the described hollow cylinder.

But first it is necessary to click on the screwdriver key, already described earlier, to remove the front panel. Then you must also insert the ends of the wires, as in the case of open wiring. Further, the working base of the switch is fixed in the glass by tightening the two side bolts, due to which in turn the teeth are pulled out and dig into the walls of the glass.

After this operation, the front part and the keys are set to regular places. Now you can turn on the power supply and check the operation of each key of the device.

Tips and advice on possible malfunctions

Perhaps at the end of the work there was a nuisance - after turning on the machine the installed device did not work. Then the output is one: you need to remove the keys and the front part again, detach the base and check the clamps of the wires. Most likely, during the final mounting operations, a poorly fixed tip of the wire fell out of the contacts.

If immediately after installation one of the keys no longer presses, then the device is defective. This happens very rarely, but there is a possibility. Then the solution is unambiguous: it is necessary to dismantle the switch and try to exchange it in the store for a new one.

Hence the main recommendation: it is better to buy instruments from famous manufacturers right away. Stable quality is, for example, the well-known brand "Legrand".

Related Videos: How to connect a switch to two keys

This video informs on the progress of the described process.

Usually a two-key switch serves for a long time. But any instruments are subject to aging. Therefore, sooner or later, the two-key switch breaks down. If the device is from a good manufacturer, it can withstand operation for two or more years. Of course, everything depends on the number of inclusions. In any case, such mechanisms are not subject to repair. In case of breakage, only their complete replacement is saved.