How to choose and correctly connect a three-key switch

In an effort to improve the convenience of controlling electrical appliances, manufacturers are creating new types of functional devices. One of these is the triple switch.

Let’s take a closer look at what design the three-key switch has and what nuances to consider when connecting the device.

Three-gang switch design

Switches of this type with standard device dimensions are equipped with three keys located back to back. Their main purpose is to provide the ability to simultaneously control three groups of connected lighting fixtures from one common access point.

Most often, such devices are installed in rooms with a complex configuration: combined bathrooms, long corridors, living rooms combined with kitchens.

The three-key switch is convenient to use to control both the main and auxiliary lighting, for example, to implement a “ceiling/walls/floor” diode lighting scheme

Three-key devices are convenient to use to control multi-arm chandeliers. To obtain three options for saturated light, they can be turned on in three stages, in which first one lamp lights up, then the next two.

Among the undeniable advantages of three-circuit devices are:

1. Presentable appearance.
2. Space saving.
3. Simplification of installation.

Simplification of the installation procedure for a three-key switch is achieved by reducing labor costs when creating a common technological niche for placing the core of the device and laying an electrical cable to it.

With properly selected electrical parameters and proper compliance with the operating mode of the three-key device, even a budget switch model can operate without failure for many decades

The design of a three-key switch is quite simple and includes two components:

• The internal part, which is a moving mechanism, where the process of closing/opening the network is carried out under the action of compression/extension of the spring.
• The outer part, which is a box with a switch key to which contacts are permanently attached.

Since the load on such devices is somewhat higher in comparison with simple types of models, the internal elements and outer casing are made only from high-quality materials.

Main types of closing devices

Switches, including triple switches, depending on the control method, can be either keyboard or sensory performance. The first are set in motion by pressing a key, the second - by touching the panel in a certain place.

Most models of touch switches are equipped with a dimmer - a device for smooth six- or seven-step adjustment until the light turns off

When choosing a dimmer, it is important to focus on the total load of the switch. Experts recommend purchasing devices with power reserves. For example: for a three-arm chandelier with lamps with a power of up to 100 Watt, choose a dimmer labeled 300 W.

Read more about what a dimmer is and how to choose one. this material.

Depending on the type of installation, triple switches are of three types:

• for external installation;
• internal, involving penetration into the wall cavity;
• combined models that have a common housing with a socket.

Combined models equipped with a socket have a narrower scope of application.This is due to the fact that their installation is impossible without altering the electrical wiring.

When installing a combined device, you have to connect two separate wires for the socket to the same point and at the same time remove phase wires from them for lighting

Installing a triple switch combined with a socket in a common housing is justified in situations where it is intended to install open wiring. Electrical safety rules strictly regulate the height of placement of switches and sockets - 150 cm from the floor.

For this reason, such models are installed in places where sockets are used quite often, provided that switches at this height are convenient to use.

Combined models are most widespread when arranging bathrooms with placement near mirrors and bedrooms in the area of ​​bedside tables.

A separate subspecies includes triple wireless switches, which can be installed anywhere and placed on any surface.

The wireless model is a different type of switch, which is more similar in design to a remote control

Wireless devices are equipped with two modules:

• Receiver – a relay-type device built into the light source. When a signal is received, it closes the lighting circuit.
• Signal transmitter – the switch itself, equipped with an energy generator. When you press a key, it processes the energy pulse into a radio signal.

Such high-tech devices are expensive. Instead of the usual electrical wiring, they use infrared or radio waves.

Switches equipped with backlit. They are convenient in the sense that in the dark they create a light signal, which serves as a good guide for quickly finding the device.

The backlight on the switches additionally acts as an indicator, which signals the non-working state of the lighting, since it turns on when voltage is not supplied to the device

When choosing such models, you should pay attention to the type of lighting source. Illuminated switches do not cause trouble only when connected in a circuit with conventional incandescent lamps or their halogen counterparts.

If fluorescent lamps or LED strips are used in a circuit with such a device, then even when turned off they will continue to emit a light pulsating glow.

Criteria for choosing wisely

When purchasing a triple switch, carefully inspect it, study the physical quantities, and check for the presence of a connection diagram.

Key points to consider when choosing a product:

1. Product body – it must be free from any kind of defects: burrs, dents and chips.
2. Key activation – should happen easily and without jamming.
3. Sound effects – when each key is turned on, a characteristic click should be heard.
4. Core – must also be free of burrs, and its terminals must work properly.

When planning to install a switch in a room with high humidity, you must choose a device with protection.

The working elements of a waterproof switch have an additional rubber or plastic shell, which protects the mechanism from direct contact with water

To simplify the installation procedure and ensure the longevity of the device, preference should be given to models whose cores are equipped with screw or clamp type terminals.

During the installation of imported triple switches, especially Korean and Chinese products, difficulties may arise that are worth thinking about in advance:

Device connection technology

Connecting three-key switches is practically no different from the installation technology of single- and two-key analogs.

The idea is that one of the power cables is connected to the switch input, and lighting cables are connected to the input contacts of the switching blocks. The only difference is in the total number of contacts of the involved switching groups located in the device body.

Carrying out preparatory work

The first thing you need to do before connecting or disassembling a three-key switch is to temporarily turn off the switch and make sure that the network is de-energized. Before starting work, you need to understand the wiring to which the device box is supposed to be mounted.

According to this connection diagram, when installing a unit for installation of a combined model, a neutral core should be laid separately from the distribution box, which will ensure the functioning of the socket

Connecting the switch will not be possible without a set of the following tools:

• voltage indicator;
• stripping tool;
• Phillips and flat screwdriver;
• perforator equipped with a crown;
• building level;
• insulating tape.

When installing the switch internally, you will need a socket box and a small portion of plaster or alabaster to place the core of the device. Self-clamping terminal blocks are used for assembling wires and connecting contacts inside the distribution box.

Assembling wires in a junction box

Two wires are fed from the shield into the distribution box.

The easiest way to determine their identity is by the color of the braid and markings:

• "zero" - painted blue;
• "phase" - has a brown braid.

To ensure the reliability of the conclusions when determining the identity of the wires, it is better to use a tester.

Six wires go from the lamps to the junction box. The master’s task is to connect three of them together, and then connect them to the working zero coming from the panel. The remaining three wires will only have to be directed to the switch and connected to its outputs.

The wires connected to the junction box are connected to each other using self-clamping terminal blocks or using the conventional twisting method

Key points to consider when assembling wires in the junction box cavity:

1. The zero of the supply wire is connected to all the “zeros” of the powered lighting fixtures.
2. The phase of the supply wire is connected to the common contact of the switch.
3. The remaining three wires coming from the switch are connected to the corresponding three phase wires coming from each lighting fixture.

By connecting one common phase to the release for all light sources, a circuit is created in which, at the moment of closing one of the switch contacts, one or another light bulb lights up.

Installation of a socket box in a niche

The socket box is used only when installing internally mounted switches, the core of which goes half into the wall. The main requirement when installing a socket box is that its edges are flush with the wall and do not protrude beyond its limits. Otherwise, after installing the core, the switch housing will stick out from the wall.

To deepen the core of the device into a niche in the cavity of the working surface, using a hammer drill equipped with a crown, make a hole with a depth sufficient to accommodate the “glass”

The socket boxes offered for sale may vary in color, shape and the presence of side projections. If we take the installation method as a basis, then “glasses” are divided into two types:

• For concrete - solid structures that are fixed in the wall by sealing with plaster or alabaster.
• For drywall – the structures are equipped with special claws, with the help of which they expand into the wall.

Regardless of the design, any socket box is equipped with pressed holes through which an electrical wire is inserted into the cavity of the structure.

We also recommend reading our other material, where we talked in detail about the technology for installing socket boxes in concrete and plasterboard. More details - go to link.

The “glass” with the wire inserted into it is buried in a pre-made niche, leveled using a level along the horizontal and vertical planes and fixed in the wall.

Connection diagram for 3-key switch

To gain access to the triple switch mechanism, the keys of the device are removed and the decorative frame is removed. This job can be easily done using a flathead screwdriver.

To remove the key, you just need to press it, bringing it to the “off” position, and carefully, without using excessive force, pry off the edge protruding from the opposite side with the tip of a screwdriver.

In fact, from the back of the triple switch you can clearly see where the phase is supplied, and where the wires coming from the lamps are connected - they are divided into separate blocks

Four wires will be connected to the installation location of the switch.

They can be combined into a four-core cable or be a combination in which:

• single-core phase comes from the distribution box;
• three-wire, which through the junction box supplies the phase to the connected lighting fixtures.

The neutral wire will run directly from the junction box to the lamps, bypassing the switch.

The incoming phase is connected to the input terminal marked with an arrow, and the three outgoing terminals are connected to the output wires of the luminaires. Which output to which terminal does not play a special role. If you want a specific terminal to be responsible for this particular lamp, reconnecting the wires will not cause much difficulty.

The wires in the mechanism are fixed using clamping screws. Before inserting the bare ends, it is important to ensure that the screw shafts are not fully seated into the slots. Insert the ends of the wires, stripped of braid, into the mechanism and tighten the screws tightly. When checking the wires for removal, no play should form.

In the mechanism, the common terminal for the phase wire is first separated, and only after that the terminals for supplying voltage from the individual lighting sections are separated.

The basic rule for connecting a three-key switch circuit is that it is not the neutral wire that is connected to the input of the device, but the mains phase wire. Neutral network wires are connected exclusively to the “zeros” of lighting fixtures. This rule is strictly regulated by the current standard - PUE.

Some craftsmen neglect this rule, directing the phase wire to the lamp, and feeding the “zero” through the break switch. With this assembly option, the network will still work. But such a solution is fraught with danger when operating the electrical system, since even if the switch is in the off position, the wiring will still remain energized.

This is dangerous because even with the usual replacement of light bulbs, a person will be at risk of electric shock each time. And if an insulation breakdown occurs at all, and there is no grounding of the connected lighting device, voltage will arise on the device body.

As a result, an electric shock will occur at the slightest contact with the surface of the device.

Features of installation of combined models

The connection diagram for a switch combined in a common housing with a socket is somewhat different from that described above. And the main difference is the presence of an additional neutral wire, laid from the distribution box directly to the outlet. In this case, the output from the switch will have two double wires.

When connecting multi-core wires, in order to prevent them from breaking off under the pressure of the screw clamp, the exposed sections of the wires are equipped with NShVI lugs

To safely connect a switch to a socket, it is better to use a wire with a cross-section of 2.5 sq. mm. And directly to the lighting fixtures from the switch, lay a 1.5 square cable.

At the final stage of installation, all that remains is to check the correct connection of the wires and install the decorative frame. To check the correct connection, you need to turn on the switch and apply voltage.

When you turn on the first key of the device, one lamp should light up, and when you turn on the second, the next chandelier horn or connected electrical appliance should light up.

The frame is fixed using a clamping insert. You need to press lightly on it and snap it on the sides with a little force.

More details about installing combined sockets are written in this article.

Conclusions and useful video on the topic

Triple switch connection sequence:

Option for assembling a three-key switch with a socket:

Device installation example:

By assembling the device in accordance with the connection diagram and adhering to safety precautions during installation, you can be sure that the switch will operate smoothly for many years.

Maybe you have already had to install a three-key switch yourself and you know the subtleties that we did not take into account in this article? Or have questions on the topic? Please write comments, share tips, ask questions in the block below.