Switching devices that enable you to turn on or off electrical devices for various purposes (chandeliers, fans, boilers and so on) are an integral part of the arrangement of electrical wiring. Due to the ease of installation and the reliability of the design, single-key switches are most widely used. They allow you to control (i.e., turn on / off) either a single lighting fixture or a whole group of lamps (for example, several spotlights mounted in a suspended ceiling).
Device and principle of operation
Structurally, a single-key switch consists of four main parts:
- base (metal, less often plastic);
- a working mechanism consisting of a contact group, clamps (for connecting electrical wires) and fastening elements;
- keys
- protective decorative element (frame or case).
The principle of operation of any single-key switch is extremely simple:
- In the “on” position, the elements of the contact group are closed and the voltage supplied to the lighting device. It begins to function.
- Conversely, in the “off” position, the contacts are disconnected, a “break” occurs in the “phase” circuit, and the lamp goes out.
Varieties of switches with one control key
According to the installation method, there are three main types of single-key switches:
- for hidden wiring, which is now used in the construction of modern buildings;
- for outdoor installation (such products are mainly in demand in suburban buildings);
- for mounting on a lighting fixture cord.
By the degree of protection of the internal mechanism from dust and moisture:
- for enclosed spaces (IP20);
- for rooms with high humidity (IP44);
- for outdoor use (IP65).
By the number of internal switched contacts:
- unipolar (with 1 group of contacts connected to the break of the wire "phase");
- bipolar (with 2 groups of contacts disconnecting both power wires from the appliance: “zero” and “phase”);
- walk-through, which have three contacts.
According to the method of connecting electrical wires, the switches are:
- with screw clamps;
- with spring-loaded clamping terminals.
Key Specifications
The main technical characteristics of single-key switches for domestic use include:
- working voltage: 220-250 V;
- rated current: from 4 to 16 A;
- degree of protection against penetration of solid particles and liquids;
- mechanical strength;
- temperature range in which the manufacturer guarantees the smooth operation of the device.
As a rule, on the back of the working mechanism, the manufacturer indicates the main technical characteristics. For example, the 10A 250V marking on the single-key switch indicates the maximum current and voltage values at which the operation of this particular product is permissible.
Leading manufacturers
Almost all manufacturers involved in the manufacture of components for the arrangement of electrical wiring did not ignore single-key switches. After all, it is they who are most in demand in the market of switching lighting fixtures. Among manufacturers popular with Russian consumers and time-tested manufacturers, it is worth noting:
- German Schneider Electric, ABB, Wessen and Gira;
- French Legrand;
- Turkish Makel, Viko and Lezard;
- Russian Svetozar, DCS and TDM Electric;
- Norwegian Hegel;
- Swedish Werkel;
- Spanish Simon and Fontini;
- Italian Bticino.
The design of the switches is very diverse (both in color, and in size, the shape of the control key and the decorative frame).
Appointment, scope, place of installation
Single-key models are designed to turn on / off one electric device or simultaneously control several devices:
- ceiling or wall lights (regardless of the number of lamps);
- fans (exhaust, supply, floor or ceiling);
- water heaters (flow or storage);
- outdoor lighting devices;
- decorative illumination of the exterior facades of buildings.
The switches are installed in the place most convenient for subsequent use. For example, indoor lighting control products are installed near entrance doors. Previously, such switches were mounted at the level of the head of a person of average height. According to modern ergonomic requirements, they are mainly mounted so that there is no need to raise a hand (that is, at a height of 80-100 cm from the floor level).
Design features and scope of passage switches
In appearance, the single-key light switch through passage is no different from the standard analogue. Its technological feature is the design and operation algorithm of internal switching contacts. When the key position is changed, the phase (L) switches from one output contact to another. If you connect one light source using two of these switches, you can turn on / off from two places independently. Such devices are widely used, for example, in arranging lighting for long corridors, flights of stairs or rooms of a large area.
A typical example: we install one switch at the beginning of the corridor, the second at the end. Then, by entering the corridor and turning on the lighting, you can turn it off when exiting.
For sconces, floor lamps, table lamps and portable lamps
Installing a single-key switch directly on the power cord from the electrical appliance to the power outlet greatly increases the ease of use of lighting devices such as wall sconces, table lamps, or floor lamps. A contact group is mounted inside a small housing, which closes or opens the electrical circuit when the control key is switched. To increase operational safety (for example, when changing the bulb without disconnecting the device from the outlet), the switching contacts in the off position “break” both wires (“zero” and “phase”). Typically, such switches are designed for currents up to 4 A, which is quite enough for most portable household electric lighting devices.
Backlight Switches
Additional comfort when controlling electrical devices is provided by illuminated single - key switches. The built - in indicator light is installed either on the protective decorative frame, or directly inside the key.
If you use such a switch to control lighting devices, then the built-in backlight will allow you to easily find it even in a dark room (that is, the indicator light will glow in the “off” position).
But to control, for example, an autonomous water heater, it is better to use a single-key switch with an internal light bulb. It will signal that the device is on. And you will always be aware of whether the unit is in operation or not.
Installation and Connection
Preparatory work that must be done before installing the single-key switch with hidden wiring:
- we will wall the walls (that is, we make grooves for laying electrical wires);
- equip openings with the subsequent installation of socket boxes and junction boxes;
- we lay electric cables in accordance with the power supply scheme of the room.
After all the preliminary work is done, proceed to the direct installation of the single-key switch. The process is quite simple and does not require special electrical training from the contractor:
- We de-energize the room by turning off the corresponding machine on the electric panel (in modern apartment buildings it is usually located on the landing).
- With a probe (digital or with a neon bulb), we must check the absence of voltage on the wires (in order to reliably make sure that we turned off the desired machine).
- We release the wires from insulation to a length of about 8-9 mm (using a special device or an ordinary construction knife).
- If the manufacturer supplies the switch in assembled form, we disassemble it into three component parts (that is, the frame, the key and the main mechanism).
- We insert the stripped ends of the wires into special holes (if we use a product with screw clamps, we tighten the screws, observing a certain caution so as not to break the thread from excessively applied forces).
- Using screws or screws, we fix the working mechanism to the socket.
Important! The excess wires are neatly laid in the socket, while avoiding strong bends.
- Install the protective frame.
- We fasten the switch key to the working mechanism (usually a small press is enough).
- We turn on the automatic voltage supply on the power shield and check the mounted device in operation.
What to look for when choosing?
Although a standard electrical switch is a fairly simple device, several key points to consider when choosing it are:
- The first thing you should pay attention to when choosing a product is the type of wiring (hidden or open) and the conditions for subsequent operation. Naturally, a switch designed for indoor use cannot be used outside.
- Then you should determine the number of contact groups. To turn on / off a normal room chandelier, usually use single-pole switches that connect the “phase” wires to the “gap”. To control powerful water-heating devices, professionals recommend the use of bipolar products that disconnect both supply wires from the device (“zero” and “phase”).
- So that the contacts do not burn during operation, and the product lasts as long as possible, it is better to choose the electrical parameters of the circuit breaker (operating voltage and rated current) with a margin.
- The appearance of the circuit breaker is also important when choosing. A variety of colors (from standard classic white to ultra-modern steel) of modern key switches allows you to choose a product that will be in harmony with the overall design of the room.
- And the last (although no less important) indicator that affects the choice of switching devices is its price. As a rule, the more expensive the product, the higher quality materials were used for its manufacture. And the design of the mechanism of expensive devices is more reliable and durable. Therefore, the cheapness when choosing components of electrical components is not worth chasing. Ultimately, not only the uptime can depend on this, but also safety.
Finally
If you correctly selected the circuit breaker model from a reliable manufacturer and made competent installation and connection, you can be sure that it will last for more than a dozen years. The main thing is to strictly comply with safety rules when carrying out any electrical work (regardless of whether you make changes to the wiring diagram after repairing the room or just decided to replace the old switch with a new one).