The two-key switch for concealed wiring is the most popular type of such electrical engineering designs. It is usually used to control luminaires with several lighting circuits, where it is required that the lamps burn alternately or all at once.
Advantages and disadvantages
The two-key internal switch is widespread due to the large number of advantageous features.
Advantages of the device for hidden wiring:
- When installing, only one cable is required, therefore, the cord is saved.
- When working in conditions of high humidity, the design is protected by a special casing. If the installation will be carried out in adverse conditions (industrial facilities, street), you need to give preference to models made of high impact materials.
- Significant savings in energy consumption. By means of the switch it is possible to regulate the number of burning lamps.
- A single switch is a potential fire hazard, two-key modifications are no exception, but they are smaller in the room, therefore, the probability of emergency situations is lower.
- It is possible to choose the optimal brightness of the lighting. Sometimes, a bright light is required in the room, and sometimes twilight.
- Designed for use in high humidity and outdoors. The case is made of high quality materials, protects internal parts from moisture and mechanical stress.
It is also worth highlighting the ability to independently adjust the illumination due to the serial connection of individual lamps or groups of lamps.
There are practically no drawbacks. At first, there may be confusion about which lamp or chandelier to turn on. A worthy alternative to such a device can only be a three-key switch.
Device and principle of operation
The advantage of a double switch is its simple design. The electrical part consists of two moving keys, a shell or a housing and terminal blocks, to which current and voltage are supplied.
Sometimes screw terminals can be installed instead of terminal blocks. Their main difference is that the terminal blocks of the wire are pressed, and they are screwed onto the bolts. The first option is preferable because of the ease of connection and longer service life.
Ways to control lighting with a switch:
- You can turn on only one light bulb or the first group of fixtures by pressing one specific key.
- Lighting will change if you press the second key. As a rule, darker places are illuminated and vice versa.
- The third option is to turn on immediately all the lighting fixtures in the room, for this, in the “on” position, two keys should appear at once.
There are two-key switches, which consist of two single-key, but isolated from each other designs. They are called modular. In addition to design, such devices can perform auxiliary functions: create a different atmosphere in the room and save energy.
Types, design and selection recommendations
A large assortment of two-gang switches for flush wiring is presented in construction stores.
The main types:
- Dimmers
- keyboards:
- rope
- rotary;
- sensory;
- push-button.
Despite the appearance of improved varieties, the key switches are still in greatest demand. They are made from different materials, they are characterized by different colors and shapes, textures. Also, the switches can be traditionally square or oval, round. Most often, structures are made of high-quality plastic and metal.
When choosing a double switch, you need to pay attention to the following specifications:
- The quality of the materials from which the contacts are made.
- Materials used to make the case and keys.
- The presence of latches or buttons, build quality.
It is necessary to study the parameters that are fixed on the case.
When purchasing electrical products, it is recommended that you familiarize yourself with certification information.
The average cost of two-gang switches ranges from 100-300 rubles. Most often, a fundamental factor in pricing is the design of the case.
Installation and Connection
Before proceeding directly to the installation and connection, it is required to carefully study the structural elements and prepare all the necessary tools. For installation and connection you will need:
- knife;
- chisel;
- side cutters;
- indicator screwdriver;
- pliers;
- slotted screwdriver;
- level;
- crosshead screwdriver.
Device connection algorithm:
- Disconnect the apartment, make sure with the indicator screwdriver that there is no voltage at the output.
- Prepare the wires, remove the insulating layer and strip the ends.
- Shorten the three wires to approximately 10 cm.
- Using a chisel, make a small groove in the wall where the wiring will later be hidden.
- Connect the wires. Squeeze the cleaned ends with pliers, then twist and carefully insulate.
- The two ends of the wires lead to the lighting device.
- From the distribution panel extend zero to each phase.
- Fit the box so that the common contact is at the bottom.
To test the operation voltage is applied. During the performance of work, it is important to monitor personal safety precautions. If there is any doubt about the quality of the work performed, it is better to contact the electricians from the Housing Office, Distribution Zone or the management company.
