Self-connection of a three-key switch: how to avoid mistakes

Self-connection of a three-key switch: how to avoid mistakes


The main purpose of the three-key switch is to save electricity. A simple device allows you to conveniently control the intensity of lighting in the room. In its connection there is nothing complicated: the procedure can be performed without any experience in electrical work.


  • 1Three-key switch: convenience and saving of electricity
    • 1.1Selection and purchase of a three-button switch
    • 1.2Connection diagram
    • 1.3A set of necessary tools
  • 2Step by step algorithm of works
  • 3Possible installation errors
    • 3.1Video: connection of a three-phase circuit breaker

Three-key switch: convenience and saving of electricity

The three-key switch allows you to save up to a third of electricity. The device is a fairly simple device, outwardly different from one- and two-key models only by the number of keys. Unlike simple switches in the three-key model, there are three groups of contacts for phase and zero. The main thing - do not confuse them when you connect.

Preparatory work includes:

  • mandatory power blackout;
  • distribution of wires (zero, phase);
  • phase search (using a screwdriver-indicator).

If the old switch is out of order or the room has been repaired, there is a need to connect a new switch. Before proceeding with the installation, you need to buy the switch itself.

Selection and purchase of a three-button switch

It is recommended to purchase equipment only known companies. This guarantees long operation of the product and its trouble-free service. When buying, please pay attention to the following details:

  • the keys should turn on with a characteristic click, do not fall;
  • The surface of the switch must be smooth, smooth;
  • on the back there should be a circuit for connecting to the electrical network;
  • it is important to check the degree of protection, to verify the possibility of connecting the product in a particular room.

The degree of protection is denoted as IP and consists of two numbers (from zero to six). The first figure is responsible for the protection from dust, and the second - for water protection.The higher the number, the more reliable the protection.For living rooms, a switch with an IP 20 rating is suitable. If the room has high humidity (bathroom, bath) or an increased amount of dust (attic), the IP indicator should be at least 44. Electrical installation outdoors requires the installation of a switch with IP 65.

Connection diagram

The production of electrical equipment is handled by domestic and foreign companies, but the circuit for connecting the three-button switch is always the same.

The general scheme will help to connect correctly any three-key switch

A set of necessary tools

To connect, you will need tools, most of which are in every house or apartment:

  • nippers and pliers;
  • cross and flat screwdrivers (depending on the features of the product);
  • screwdriver-indicator;
  • insulating tape;
  • screwdriver;
  • Knife or stripper (tool for easy removal of insulation).

Step by step algorithm of works

  1. The switch is disassembled for easy installation. Most three-key switches are designed for flush mounting, so the shrouds must be pre-made in advance, and wires are removed from the junction box.
  2. The supply of electricity is cut off at the work site.
  3. Phase-zero is determined using the indicator. The upper contacts are fed with a phase, and the bottom is zero.
    Correctly connect the contacts will help marking on the back of the switch
  4. The wires are fixed with special screws using a screwdriver or screwdriver.
    Reliable fastening of wires by screws will ensure trouble-free operation of the switch
  5. The device is mounted in the wall and is fixed in the pad by side pawls, which are on each switch. When installing, care should be taken to avoid misalignment of the circuit breaker and the interlacing of the cables.
    Marking wires to avoid confusion
  6. After fixing, a decorative cover and keys are installed at the installation site.
  7. The device is tested.

Possible installation errors

  1. The switch is not in phase, but in zero.It is the key of the switch that should give the phase break. If you do the opposite, you can get an electric shock when replacing a light bulb.
  2. The phase is not triggered by the general contact of the switch, but by one of the outgoing ones.In this case, the device will not work correctly. All the bulbs will light up only if you press all the keys at the same time. But if you press only the key that the phase does not initially come from, the device does not light up at all.
  3. The connection of the zero wire to the chandelier is not to the common zero in the switchbox, but to one of the phase wires.To avoid this, apply and observe the color coding of the wires. At the installation site of the switch, three groups of two-wire cables come out of the wall. Wires of blue color - zero; brown (black or red) - phase. It is important not to confuse anything to avoid short circuits. The input of the three-key switch must be supplied with a phase wire. Phase and zero cables are determined visually (by color) and with the help of a screwdriver-indicator: when in contact with the phase, the indicator lamp will light up.

Video: connection of a three-phase circuit breaker

The main thing when connecting a three-button switch is to remember the safety precautions. The network must be de-energized before the start of the work, otherwise the electric shock can not be avoided.

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