Wiring diagram for a two-gang switch for two bulbs: wiring features

Amir Gumarov
Checked by a specialist: Amir Gumarov
Author: Elena Pykhteeva
Last update: May 2024

Doing electrical work yourself can save you a lot of money and time. To perform such operations, you need to study their features, order of execution, etc.

It is these issues that we will deal with in our article, having considered the features of performing electrical work. The information is presented in the form of step-by-step instructions, equipped with detailed photos that illustrate the step-by-step installation process.

And although the scheme for connecting a two-gang switch to two bulbs at first may seem complicated, even a beginner electrician will cope with the installation, having understood the principle of operation of such a device.

Two-Key Switch Overview

A switch of this type is most often used for lighting in two adjacent rooms or for controlling a multi-path chandelier. The first option is traditionally used for a separate version of the bathroom or for fixtures installed in different rooms.

If it is convenient to turn on both lighting devices from one point, it is more reasonable to install one device with two keys, and not two identical single-key switches.

If you organize the control of the chandelier in this way, you can adjust the illumination of the room, including only part of the bulbs or all at once. Such a scheme can be useful in the kitchen, for example, to turn on the upper and lower lights.

Not too experienced master can be not just to figure out with schemes and the procedure for connecting a switch with two keys. But if you understand the principle and sequence of work, then there will be no problems.

Switch mounting features

Suppose that our task is to equip the new building with electrical wiring, which has not yet been touched by the hand of an electrician. Consider the features of the implementation of electrical work in stages.

Stage # 1 - preparatory work

First you need to prepare the necessary tools and materials:

  • single pole machine and RCD;
  • switch with two keys;
  • junction box;
  • two lamps;
  • din - rail to install devices to protect wiring and hosts;
  • suitable for size and type of sockets;
  • power cable;
  • electrical tape;
  • perforated tape for cable installation;
  • fasteners;
  • screwdrivers, Phillips and flat, or a screwdriver with nozzles;
  • voltage indicator;
  • knife, nippers, pliers, etc.

Start the connection with the preparatory phase. First you need to install a junction box in which all the wires will be assembled and connected in accordance with the scheme.

To protect the circuit from breakdowns and overloads, you will need an automatic machine, and to protect the owners of the premises from shocks in case of current leakage, an RCD is required. These devices must be mounted in the switchboard of a house or apartment, where suitable places are provided for them.

Double circuit breaker connection diagram
The connection diagram of the double switch will help to connect all the elements and wires correctly. Understanding the principles will greatly facilitate installation.

If for some reason such installation is not possible, the RCD and the machine are installed on a mounting rail mounted directly on the wall. After that, you need to put the socket for the switch.

The sockets should be selected depending on the wall material: for concrete or drywall. Devices for concrete are also used on other similar bases: for brick, gas and foam concrete, expanded clay blocks, etc. A hole of the right size is made in the wall, and then the box is fixed with a plaster or cement mortar.

Preparing for mounting the circuit breaker
Installation should begin with the installation of protective devices (usually in the shield), junction box and socket box for the switch

Stage # 2 - selection and installation of a suitable socket

For plasterboard works, other models and installation methods are used. rosette. They are equipped with spacer elements that allow you to fix the device in the hole. The same sockets are taken for installation on a wall with paneling made of chipboard, plywood, etc.

Now you can start wiring. In accordance with the scheme drawn up, you need to make markings and lay the gates, if a hidden cable routing is planned.

Wires in the socket
To connect the switch in the socket, you need to leave about 10 cm of wire. Cores should be stripped 10 mm from insulation
Concrete Socket
Podrozetniki intended for installation on concrete are installed in the hole and fixed with plaster or other suitable binding solution

When choosing a socket for a switch, you need to pay attention to this nuance. New models of such devices are made of plastic, they have a diagonal of 67 mm. Old, usually metal, analogues are slightly larger, they have a diagonal of 70 mm. This small difference can be decisive.

Modern two-gang switches are great for 67 mm socket boxes. The mechanism can be fixed inside with the help of spacer legs or with screws.

In metal models, three additional millimeters can greatly complicate the installation of the switch, since the length of the spacer legs, which are usually located on the sides of the mechanism, may not be enough to secure it securely.

Drywall Socket
For installation in a false wall made of drywall or other lightweight material, you need to take the socket outlets, which are attached using spacers

If the installation is carried out in a new type of socket, in addition to the struts, a more reliable method of fastening with screws for which there are holes on the metal frame of the switch should be used. Before starting work, make sure that there is no voltage on the communications.

Stage # 3 - the intricacies of working with wires

For a two-gang switch, you need to take a three-wire wire, which is supplemented by a grounding conductor.Such cables have double insulation: internal, for each individual core, and external, for the entire cable.

First, the power cable, lead to the protective devices, then lay a line from the protective device to the junction box.

Junction box with wires
Four wires should come out of the junction box: to the UZO and the circuit breaker, to the switch, and two more to two lamps

From the box, the wire leads to the socket, and then two more lines to the lamps. In the junction box, you need to leave the ends about 150 mm, and for the rosette there is enough backlog of 100 mm.

Now need install an RCD and an automatic machine. The rating of protection devices is determined separately for each particular case, depending on the lighting power.

Most often, an RCD is installed in apartments at two poles to disconnect, if necessary, two separate lines, at the entrance to each of them put a single-pole machine. In case of low power consumption, both lines can be connected for protection to a single-pole RCD, after which a single-pole circuit breaker is connected to the circuit to protect the wiring.

Then you need to connect the individual cable segments to a common network. To do this, remove the outer insulation layer. Usually they start with a wire leading to the junction box from protective devices, then separate conductors are freed from insulation.

Under the insulation there are three wires, insulation on which varies in color.

Installation of electrical wires
The internal insulation of the three-wire wire varies in color for each core: for phase, zero and ground. This mark must be strictly observed.

One core is designed for zero, the second for grounding, the third for phase. You need to remember which color wire is highlighted for each function.

Before connecting the ends gently exempt from isolation. In this case, you need to make sure that the color marking on the cores connected to the machine matches the ones that come out of it. If the neutral wire passes up on the right side, then at the bottom it should also be on the right.

Grounding for lighting fixtures is not always provided for in standard apartment schemes. In this case, the third wire remains unused.

If there is a ground loop, it should be connected to further protect the lighting from possible accidents. This circuit is connected to the corresponding contacts on the lighting fixtures. Newer luminaire models usually have grounding contacts.

Such a precaution when connecting a two-gang switch to two bulbs is mandatory if the lighting is installed in a bathroom or other room with high humidity. Grounding conductors that have not been used should be insulated and laid so that they do not interfere with further installation work.

Stage # 4 - installation and connection of the switch

Outside, the standard model of the switch consists of two keys and a decorative frame, although the design may vary. Behind them is a working mechanism. To open it, you need to remove the keys. To do this, each of them is picked up with a screwdriver and disconnected. Some manufacturers make small tabs on the edges of the keys to facilitate the process of disassembling the device.

After the keys are removed, you need to remove the decorative frame. To do this, unscrew the fasteners or open the latches. Device contacts may vary by model. Usually they are made screw or self-locking. Now you can connect and install the switch.

Installing the switch in the socket
In addition to the spacer tabs, screws are used to secure the switch in the socket. First you need to align the position of the device using the level

After removing the outer insulation layer, approximately 10 mm of insulation coating should be removed from each core - to clean. Previously, it is worth exploring the design features of the device, paying attention to the type of contacts.The switch must be turned around and examined.

There is usually a circuit with which you can correctly connect. If such information is not available on the device, it must be searched in the instructions or use devices to determine which contact is intended for the phase input and which two are outputs.

Lack of the necessary marking is a rare case, typical for some old models of circuit breakers from the Soviet era or for cheap low-quality devices made in China. Sometimes simple logic helps: the input and output are almost always located on opposite sides. There is only one input, and there are always two outputs in such switches.

Switch connection
The input and output for contacts are usually located on opposite sides. The phase input is indicated by L, and the connection of the output contacts is indicated by arrows

Typically, the letter L designates the connection location of the input of the phase wire, and the arrows on the opposite side indicate the connection location of the wires responsible for the operation of a separate key.

The core, which is most often covered with white insulation, must be connected to the input of the phase, and the other two wires, which in the photo are blue and yellow-green, to the corresponding nests. After all the contacts are connected, you need to deploy the device and install it in the socket.

On models with self-locking contacts, connection is extremely simple. The stripped edge of the wire simply needs to be inserted into the connection point. A clamp is installed there, which automatically fixes the connection with a spring. Thus, all three wires are connected.

It is necessary to carefully monitor the color marking of individual cores. After they are inserted into the connectors, pull back a little to make sure that the connection is secure. If it is necessary to remove the fixed cores from the clamping contacts, then the connection must be disconnected.

To do this, buttons are provided next to each clip; they can be located at the ends of the device. When the button is pressed, the clip opens and the wire can be easily removed. On switches with screw-type contact locks, the entry and exit designation for wires is often missing.

Usually, the phase inlet is located on top, and two outputs on the bottom. In the design of such devices there is a plate to which movable output contacts are attached, their purpose is obvious. To fix the contacts in such a device, you need to unscrew the clamp screw, insert the stripped edge of the wire into the hole, then screw the fasteners back.

Dual Switch Contacts
The arrows on the left indicate the screws of the output contacts of the double switch, on the right - the screws that adjust the position of the spacer tabs for mounting the device in the socket

In this case, it must be ensured that the edge of the insulation does not appear at the clamping point. Two more screws in such devices serve for fixing the presser spacers. They are unscrewed to complete the installation of the switch in the socket. Now you can start connecting the fixtures.

Stage # 5 - completion of installation work

You need to take a wire of suitable length and lay it in the prepared channel or on the wall / ceiling in accordance with the marking. It is necessary to strip the core and connect it to the desired contact. If standard plastic is used for this terminal blockthen it is enough to strip 5 mm of wire.

In the same way, power is supplied to the second lamp. Unused ground wires must be insulated. Now you should take the supply wire that will connect the junction box and the wire coming from the junction box to the switch. The ends of these wires should be freed from the outer insulation.

Earth conductor insulation
If ground wires (here they are yellow) are not used, they must be insulated and removed during installation
Wire connection
The connection of the individual cores in the junction box can be performed by the twist method, this is a simple but not the safest option

The veins are stripped approximately 40 mm. After this, you need to connect two phase wires into a twist. Movement is recommended to make clockwise.

Twisting can be done manually at first, but then you need to strengthen the connection using pliers. Only 5-7 turns of twisting should be left, excesses are removed with nippers.

This method of connecting electrical communications is considered obsolete and is even prohibited in the PUE p. 2.1.21.

Professionals recommend using the following methods for installing electrical wires:

  • soldering;
  • welding;
  • crimping;
  • compression joints (screws, clamps, etc.)

Features of the popular and reliable methods of connecting wires we examined in the next article.

If the ground conductor is not used at this stage, it is recommended to take care of its insulation again. Now you need to clean the outer and inner coatings of the end of the phase wire leading to the lamp. It must be connected to one of the wires that exit the switch.

In the same way, you need to do with the phase wire, which leads from the second lamp, it is connected to the second core coming out of the switch.

Again, isolate all unclaimed ground conductors and lay them in the junction box. If grounding is provided, the corresponding wires must be connected in series. It remains to connect the zero cores: one from the power cord and two more from the fixtures. They are simply twisted together.

Stage # 6 - checking the health of the circuit

Now it remains to screw the bulbs into the lampholders and check the operation of the circuit.

Dual switch connection
At the end of the assembly, the connection circuit of the double switch will look something like this. At this stage, you need to check: turn on the RCD and the machine, and then the keys - alternately and together. After checking the protection device, you need to disable

First you need to turn on the RCD and the machine. After that, the operation of each switch button is checked one by one, and then both lamps are turned on and off at the same time.

If everything is done correctly, the lamps will light up and go out in accordance with the position of the switch keys

After this, it is necessary to turn off the protective devices and insulate all the connection points and complete the installation of the two-gang switch, by installing a decorative frame.

Conclusions and useful video on the topic

The visual installation process of the two-key switch can be viewed here:

In fact, it is not difficult to connect such a device, you only need to understand the order of all operations and comply with security requirements. It’s better and easier to use modern appliances and materials, since they are easier to install and they are better combined with each other.

Do you want to clarify the incomprehensible moments on the installation of the switch, which we have not covered in sufficient detail in this article? Or would you like to supplement the above material with valuable comments / advice based on personal experience? Please write your questions in the comments section, express your opinion, add useful recommendations.

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Visitors Comments
  1. Gennady

    My dad taught me to twist wires (make twists), when assembling boxes (he is an electrician, as, in fact, I am). According to my observation, I can say that a correctly made twist is a guarantee of a good, strong connection. True, not everywhere. However, it is better not to do it in the apartment, and there are various reasons for this. Twisting deforms the wire, making it unsuitable for reusable use (tips). Soldering, welding, crimping and clamping are good, but each situation has its own way of crimping the wire. Sometimes you can’t do without twisting either. Old electricians will support me, but new ones probably will not understand.

    • master zheka

      Gennady, can you list the reasons why you DO NOT need a twist in the apartment? The fact that twisting deforms the wire is understandable, but you do not pull twists in the apartment once a week or once a month? Oh, very rarely happens in practice, when you need to climb into the distribution box to scatter wires, and at this frequency, even aluminum wiring can withstand several tens of deformations, having served for 100 years (and there will be enough copper wiring for your great-grandchildren).

    • Expert
      Amir Gumarov
      Expert

      Good afternoon, Gennady. How to connect the wires "know" the "Rules for the installation of electrical installations." The book was not invented from scratch - it was written by life. When people were struck by electricity, when houses, enterprises and specialists burned due to wiring, they found out the reasons and obliged designers and installers to follow the right technologies.

      Twisting caused a lot of fires, which led to the appearance in paragraph 2.1.21 of the Rules and several subsequent ones (attached screenshot).

      Attached photos:

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