Before laying electrical networks in a house or apartment, it is mandatory to draw up. In addition to cable lines, it contains many other symbols. Since most installation work can be done independently, it is necessary to correctly read and decipher the designation of sockets and switches on the drawings. Such knowledge will allow you to avoid installation errors, and each product will take its place assigned on the diagram.
Designation of sockets in the drawings
On electrical diagrams, sockets are designated different ways, depending on its design and connection features.
- Figure 1 shows a socket with two poles for connecting the phase and neutral wires. It is overhead and does not have grounding. It is depicted as a semicircle lying on a section, with one vertical stripe located on top. The presence of two stripes indicates a double socket.
- Figure 2 also shows a surface-mounted two-pole socket, but with grounding. There is a horizontal strip on the semicircle, and one vertical strip extends upward. If there is another strip coming out of each corner, this means that the socket has three poles and is designed for 380 V.
- The 3rd figure shows the symbol of a built-in socket for hidden installation. The semicircle is cut in half with a vertical strip. The presence of two stripes indicates a dual socket design.
Other socket designs are designated according to the same principle.
They also have a semicircle with outgoing contacts.
- Figure 4 corresponds to built-in 2-pole grounded receptacles. In the drawing they are cut into a vertical strip, and a horizontal line is located on top of the semicircle. Three-pole sockets are indicated by additional stripes coming out of the corners.
- Figure 5 denotes a two-pole built-in structure with phase and neutral, equipped with grounding. The designation on the diagram is the same as in the 4th figure, with the exception of two vertical stripes.
- Figure 6 shows sockets protected by a cover. They have two poles - and can be with or without grounding.
Designation of switches in the drawings
All switches are schematically depicted as a circle with a line on the top. One hook located at the top of the dash indicates a single-gang open type switch. Two hooks correspond to a two-gang switch. An icon with three hooks indicates a switch with three keys. (Figures 1,2)
In the case where a perpendicular strip is placed above the main line, this indicates a switch design intended for hidden installation (Figure 3). One, two or three lines correspond to a one-, two- or three-key switch.
If the circle is completely filled in black, it is an image of a moisture-resistant open type switch.
Figure 4 shows a circle intersected by a line with dashes located at the ends. Thus, pass-through switches in two positions are indicated on electrical diagrams. The circuit mirrors two ordinary switches. The number of perpendicular lines indicates the number of keys. The designation of moisture-resistant switches appears as a filled circle.
Figures 5, 6 and 7 show switches arranged together with receptacles in one block. This placement significantly saves space and facilitates installation. To connect, only one wire is required, laid in a single groove.
Figure 5 shows a regular switch connected to a standard outlet. The entire unit is designed for hidden installation. Next option(Figure 6) is more complex. It includes a grounded socket, as well as a one- and two-gang switch. Figure 7 shows a block consisting of two conventional switches and one socket.
Designation of lamps on the diagram
Lamps occupy a leading place in lighting design. In modern diagrams, they are not only marked individually, but can also be displayed in the form of so-called dynamic blocks, which are very convenient for designing lighting in specific rooms.
These designations are used not only for indoor but also for outdoor lighting. These diagrams contain additional elements that are used during the installation process.
Designations of network elements
In addition to lamps, sockets and switches, each electrical network contains a large number of other elements. Among them, transformers, switches, electrical installation products and other parts are most often found.
The components and products used are necessarily displayed on electrical diagrams and drawings in accordance with established standards. In order to correctly read such a diagram, you need to know exactly not only, but also specifications each element. All connections between individual parts are indicated using special positional designations.
Conventional graphic symbols are performed using specially developed standardized geometric symbols. They can be used separately for each element or in combination with other types of products. The overall meaning of a particular geometric image largely depends on these combinations.
In addition to the schematic drawing, the displayed elements contain positional designations with digital and letter markings. In addition, there are qualification designations that establish the type of connection, current and voltage values, adjustment methods, electrical connections and other characteristics.
Designation of panels, boxes, cabinets
IN electrical networks much attention is paid reliable protection cable and wire entries, as well as various switching equipment. For these purposes, all kinds of designs of cabinets, panels or boxes made of metal or plastic are widely used. All types of switchboard equipment are designed for different voltages. They differ overall dimensions, depending on the number of installed instruments and devices. For abbreviated designations, the appropriate capital letters“Sh”, “Shch”, “I”.
In modern conditions, residential switchboards, displayed on diagrams as “ShchK”, are becoming increasingly popular. They are successfully used in new facilities or in the reconstruction of electrical wiring in old buildings. Models of switchboards are divided into ShchKU - apartment metering switchboard and ShchKR - apartment distribution switchboard.
Quite often, on electrical diagrams of sockets, switches, and other elements, there are designations in the form ША and ША, which correspond to cabinets or automation panels. In addition, there are conventional symbols SHAVR - automatic transfer cabinet, ShchAP - automatic switchboards.
How to Read Electrical Diagrams
Any electrical circuits can be presented in the form of drawings (circuit and installation diagrams), the design of which must comply with ESKD standards. These standards apply to both electrical wiring or power circuits and electronic devices. Accordingly, in order to “read” such documents, it is necessary to understand the symbols in electrical circuits.
Regulations
Taking into account the large number of electrical elements, a number of normative documents have been developed for their alphanumeric (hereinafter referred to as BO) and conventional graphic designations (UGO) to eliminate discrepancies. Below is a table showing the main standards.
Table 1. Standards for graphic designation of individual elements in installation and circuit diagrams.
| GOST number | Short description |
| 2.710 81 | This document contains GOST requirements for BO various types electrical elements, including electrical appliances. |
| 2.747 68 | Requirements for the size of display of elements in graphical form. |
| 21.614 88 | Accepted codes for electrical and wiring plans. |
| 2.755 87 | Display of switching devices and contact connections on diagrams |
| 2.756 76 | Standards for sensing parts of electromechanical equipment. |
| 2.709 89 | This standard regulates the standards in accordance with which contact connections and wires are indicated on diagrams. |
| 21.404 85 | Schematic symbols for equipment used in automation systems |
It should be taken into account that the element base changes over time, and accordingly changes are made to regulatory documents, although this process is more inert. Let's give a simple example: RCDs and automatic circuit breakers have been widely used in Russia for more than a decade, but there is still no single standard according to GOST 2.755-87 for these devices, unlike circuit breakers. It is quite possible that this issue will be resolved in the near future. To keep abreast of such innovations, professionals monitor changes in regulatory documents; amateurs do not have to do this; it is enough to know the decoding of the main symbols.
Types of electrical circuits
In accordance with ESKD standards, diagrams mean graphic documents on which, using accepted notations The main elements or nodes of the structure, as well as the connections connecting them, are displayed. According to the accepted classification, there are ten types of circuits, of which three are most often used in electrical engineering:
If the diagram shows only the power part of the installation, then it is called single-line; if all elements are shown, then it is called complete.
If the drawing shows the wiring of the apartment, then the locations of lighting fixtures, sockets and other equipment are indicated on the plan. Sometimes you can hear such a document called a power supply diagram; this is incorrect, since the latter shows how consumers are connected to a substation or other power source.
Having dealt with the electrical circuits, we can move on to the designations of the elements indicated on them.
Graphic symbols
Each type of graphic document has its own designations, regulated by relevant regulatory documents. Let us give as an example the basic graphic symbols for different types electrical circuits.
Examples of UGO in functional diagrams
Below is a picture depicting the main components of automation systems.
Examples of symbols for electrical appliances and automation equipment in accordance with GOST 21.404-85 Description of symbols:
- A – Basic (1) and acceptable (2) images of devices that are installed outside the electrical panel or junction box.
- B - The same as point A, except that the elements are located on the remote control or electrical panel.
- C – Display of actuators (AM).
- D – Influence of MI on the regulating body (hereinafter referred to as RO) when the power is turned off:
- RO opening occurs
- Closing RO
- The position of the RO remains unchanged.
- E – IM, on which a manual drive is additionally installed. This symbol may be used for any RO provisions specified in paragraph D.
- F- Accepted mappings of communication lines:
- General.
- There is no connection at the intersection.
- The presence of a connection at the intersection.
UGO in single-line and complete electrical circuits
There are several groups of symbols for these schemes; we present the most common of them. To obtain complete information, you must refer to the regulatory documents; the numbers of state standards will be given for each group.
Power supplies.
To designate them, the symbols shown in the figure below are used.
UGO power supplies on schematic diagrams (GOST 2.742-68 and GOST 2.750.68) Description of symbols:
- A is a constant voltage source, its polarity is indicated by the symbols “+” and “-”.
- B is an electricity icon indicating alternating voltage.
- C is a symbol of alternating and direct voltage, used in cases where the device can be powered from any of these sources.
- D – Display of battery or galvanic power source.
- E- Symbol of a battery consisting of several batteries.
Communication lines
The basic elements of electrical connectors are presented below.
Designation of communication lines on circuit diagrams (GOST 2.721-74 and GOST 2.751.73) Description of symbols:
- A – General mapping adopted for various types electrical connections.
- B – Current-carrying or grounding bus.
- C – Designation of shielding, can be electrostatic (marked with the symbol “E”) or electromagnetic (“M”).
- D – Grounding symbol.
- E – Electrical connection with the device body.
- F - On complex diagrams, consisting of several components, a broken connection is thus indicated; in such cases, “X” is information about where the line will be continued (as a rule, the element number is indicated).
- G – Intersection with no connection.
- H – Joint at intersection.
- I – Branches.
Designations of electromechanical devices and contact connections
Examples of the designation of magnetic starters, relays, as well as contacts of communication devices can be seen below.
UGO adopted for electromechanical devices and contactors (GOSTs 2.756-76, 2.755-74, 2.755-87) Description of symbols:
- A – symbol of the coil of an electromechanical device (relay, magnetic starter, etc.).
- B – UGO of the receiving part of the electrothermal protection.
- C – display of the coil of a device with mechanical interlock.
- D – contacts of switching devices:
- Closing.
- Disconnecting.
- Switching.
- E – Symbol for designating manual switches (buttons).
- F – Group switch (switch).
UGO of electric machines
Let us give several examples of displaying electrical machines (hereinafter referred to as EM) in accordance with the current standard.
Designation of electric motors and generators on circuit diagrams (GOST 2.722-68) Description of symbols:
- A – three-phase EM:
- Asynchronous (squirrel-cage rotor).
- Same as point 1, only in two-speed version.
- Asynchronous electric motors with phase-phase rotor design.
- Synchronous motors and generators.
- B – Collector, DC powered:
- EM with permanent magnet excitation.
- EM with excitation coil.
UGO transformers and chokes
Examples of graphic symbols for these devices can be found in the figure below.
Correct notation transformers, inductors and chokes (GOST 2.723-78) Description of symbols:
- A – Data graphic symbol Inductors or transformer windings may be designated.
- B – Choke, which has a ferrimagnetic core (magnetic core).
- C – Display of a two-coil transformer.
- D – Device with three coils.
- E - Autotransformer symbol.
- F – Graphic display of CT (current transformer).
Designation of measuring instruments and radio components
A brief overview of the UGO of these electronic components is shown below. For those who want to become more familiar with this information, we recommend viewing GOSTs 2.729 68 and 2.730 73.
Examples of graphic symbols for electronic components and measuring instruments Description of symbols:
- Electricity meter.
- Picture of an ammeter.
- Device for measuring network voltage.
- Thermal sensor.
- Fixed value resistor.
- Variable resistor.
- Capacitor (general designation).
- Electrolytic capacity.
- Diode designation.
- Light-emitting diode.
- Image of a diode optocoupler.
- UGO transistor (in this case npn).
- Fuse designation.
UGO lighting devices
Let's consider how to schematic diagram electric lamps are displayed.
Description of symbols:
- A – General image of incandescent lamps (LN).
- B – LN as a signaling device.
- C – Typical designation of gas-discharge lamps.
- D – High-pressure gas-discharge light source (the figure shows an example of a design with two electrodes)
Designation of elements in the wiring diagram
Concluding the topic of graphic symbols, we give examples of displaying sockets and switches.
How sockets of other types are depicted is easy to find in the regulatory documents that are available on the Internet.
Reading diagrams is impossible without knowledge of the conventional graphic and letter designations of the elements. Most of them are standardized and described in regulatory documents. Most of them were published in the last century and new standard only one was adopted, in 2011 (GOST 2-702-2011 ESKD. Rules for the execution of electrical circuits), so sometimes a new element base is designated according to the principle “as who came up with it.” And this is the difficulty of reading circuit diagrams of new devices. But, basically, the symbols in electrical circuits are described and are well known to many.
Two types of symbols are often used on diagrams: graphic and alphabetic, and denominations are also often indicated. From this data, many can immediately tell how the scheme works. This skill is developed over years of practice, and first you need to understand and remember the symbols in electrical circuits. Then, knowing the operation of each element, you can imagine the final result of the device.
Drawing and reading different diagrams usually require different elements. There are many types of circuits, but in electrical engineering the following are usually used:
There are many other types of electrical circuits, but they are not used in home practice. The exception is the route of cables passing through the site and the supply of electricity to the house. This type of document will definitely be needed and useful, but it is more of a plan than an outline.
Basic images and functional features
Switching devices (switches, contactors, etc.) are built on contacts of various mechanics. There are make, break and switch contacts. The normally open contact is open; when it is switched to operating state, the circuit is closed. The break contact is normally closed, but under certain conditions it operates, breaking the circuit.
The switching contact can be two or three position. In the first case, first one circuit works, then another. The second one has a neutral position.
In addition, contacts can perform different functions: contactor, disconnector, switch, etc. All of them also have a symbol and are applied to the corresponding contacts. There are functions that are performed only by moving contacts. They are shown in the photo below.
Basic functions can only be performed by fixed contacts.
Symbols for single line diagrams
As has already been said, single-line diagrams indicate only the power part: RCDs, automatic devices, automatic circuit breakers, sockets, circuit breakers, switches, etc. and connections between them. The designations of these conventional elements can be used in electrical panel diagrams.
The main feature of graphic symbols in electrical circuits is that devices similar in principle of operation differ in some small detail. For example, a machine (circuit breaker) and a switch differ only in two small details - the presence/absence of a rectangle on the contact and the shape of the icon on the fixed contact, which display the functions of these contacts. The only difference between a contactor and a switch designation is the shape of the icon on the fixed contact. It's a very small difference, but the device and its functions are different. You need to look closely at all these little things and remember them.
There is also a small difference between the symbols of the RCD and the differential circuit breaker. It also only functions as moving and fixed contacts.
The situation is approximately the same with relay and contactor coils. They look like a rectangle with small graphic additions.
In this case, it’s easier to remember, since there are quite serious differences in appearance additional icons. With a photo relay it’s so simple - the rays of the sun are associated with the arrows. A pulse relay is also quite easy to distinguish by the characteristic shape of the sign.
A little easier with lamps and connections. They have different “pictures”. A detachable connection (such as a socket/plug or socket/plug) looks like two brackets, and a detachable connection (such as a terminal block) looks like circles. Moreover, the number of pairs of checkmarks or circles indicates the number of wires.
Image of tires and wires
In any circuit there are connections and for the most part they are made by wires. Some connections are buses - more powerful conductor elements from which taps can extend. Wires are indicated by a thin line, and branches/connections are indicated by dots. If there are no points, it is not a connection, but an intersection (without an electrical connection).
There are separate images for buses, but they are used if they need to be graphically separated from communication lines, wires and cables.
On wiring diagrams it is often necessary to indicate not only how the cable or wire runs, but also its characteristics or installation method. All this is also displayed graphically. This is also necessary information for reading drawings.
How switches, switches, sockets are depicted
There are no standards-approved images for some types of this equipment. So, dimmers (light regulators) and push-button switches remained without designation.
But all other types of switches have their own symbols in electrical diagrams. They come in open and hidden installations, respectively, there are also two groups of icons. The difference is the position of the line on the key image. In order to understand in the diagram what type of switch we are talking about, this must be remembered.
There are separate designations for two-key and three-key switches. In the documentation they are called “twin” and “twin”, respectively. There are differences for cases with different degrees of protection. In rooms with normal operating conditions, switches with IP20, maybe up to IP23, are installed. In wet rooms (bathroom, swimming pool) or outdoors, the degree of protection should be at least IP44. Their images differ in that the circles are filled in. So it's easy to distinguish them.
There are separate images for the switches. These are switches that allow you to control turning the light on/off from two points (there are also three, but without standard images).
The same trend is observed in the designations of sockets and socket groups: there are single, double sockets, and there are groups of several pieces. Products for rooms with normal operating conditions (IP from 20 to 23) have an unpainted middle; for wet rooms with a housing of increased protection (IP44 and higher), the middle is tinted dark.
Legend in electrical circuits: sockets different types installation (open, hidden)
Having understood the logic of the designation and remembering some initial data (what is the difference between the symbolic image of an open and hidden installation socket, for example), after a while you will be able to confidently navigate the drawings and diagrams.
Lamps on diagrams
This section describes the symbols in the electrical circuits of various lamps and fixtures. Here is the situation with the notation of the new element base better: there are even signs for LED lamps and lamps, compact fluorescent lamps (housekeepers). It’s also good that the images of lamps of different types differ significantly - it’s difficult to confuse them. For example, lamps with incandescent lamps are depicted in the form of a circle, with long linear fluorescent lamps - a long narrow rectangle. The difference in the image of a linear fluorescent lamp and an LED one is not very big - only dashes at the ends - but even here you can remember.
The standard even includes symbols in electrical diagrams for ceiling and pendant lamps (socket). They also have a rather unusual shape - circles of small diameter with dashes. In general, this section is easier to navigate than others.
Elements of electrical circuit diagrams
Schematic diagrams of devices contain a different element base. Communication lines, terminals, connectors, light bulbs are also depicted, but in addition, there is a large number of radio elements: resistors, capacitors, fuses, diodes, thyristors, LEDs. Most of the symbols in the electrical circuits of this element base are shown in the figures below.
Rarer ones will have to be looked for separately. But most circuits contain these elements.
Letter symbols in electrical diagrams
Except graphic images elements on the diagrams are signed. It also helps to read the diagrams. Next to the letter designation of an element there is often its serial number. This is done so that later it is easy to find the type and parameters in the specification.
The table above shows international designations. There is also a domestic standard - GOST 7624-55. Excerpts from there with the table below.
If you have ever thought about designer renovation, then you have probably been notified that engineering plans for the premises will be created. In this technical documentation, the designations of LED lamps in the drawings according to GOST are carried out in accordance with existing standards and norms, however, a person who does not have a technical education will not be able to understand such a “map”.
In fact, there is nothing complicated in this process, but you just need to find a list of symbols that are used today. Of course, the documentation and GOST format are revised from time to time, but it does not change radically, it is only supplemented.
Relevance of using drawings
When planning a renovation, creating a drawing with lamp designations according to GOST seems like a waste to many customers. Money and time, since construction work can be carried out without this document. Of course, in the past everything was exactly like this, but over time the situation is gradually changing.
One of the main problems is the increasing complexity of infrastructure. Today, builders and DIYers are forced to hide vast amounts of wires, cables and wiring in walls and floors to power all the electronics they use. In the drawings, according to GOST, each wire and other elements are indicated so that, if additional work is necessary, nothing important is damaged. It is necessary to know the designation of lamps in order to be able to read such plans.
Moreover, the use of signs to designate a lamp or chandelier can significantly speed up the work, since the foreman does not need to make any decision about the placement of lighting fixtures - everything was decided in advance by a specialized specialist. In this case, the chance of error is significantly reduced, which prevents unnecessary financial losses.
It is worth understanding that The territory of each country has its own separate GOST, even the countries of the former USSR and the CIS. For this reason, it is impossible to download from the Internet the first list of projects with markings that come across and use it - the builder may simply not understand it.
However, a single list of signs and symbols is often used, but the requirements differ in design rules and other similar details.
So, if you decide to understand the technical documentation presented to you, then you should make sure that a number of important points are met. First of all, it is worth remembering that all sizes according to GOST are indicated in millimeters, which at first scares many people who have not encountered such a system.
Moreover, if you do not have the necessary experience, then you should know the approximate layout of the room. If this is your house, room or dwelling, then you should not have any problems with this. Otherwise, it is recommended to try to find photographs in order to have an association. It is extremely difficult to imagine the design of a future room using only one plan.
As mentioned earlier, there are really a lot of symbols for indoor lighting - there are Special symbols even for certain types of lighting fixtures, making it difficult to read. In the territory Russian Federation
symbols of lamps are often used, which are presented in the following illustration. If the designer or planner wishes to use alternative symbols, they are indicated in a special reference section, which is usually presented on last pages
- plan or in the application.
- Find symbols;
- Combine the plan with the location of the room in space;
Try to visualize the room and the placement of lamps. In general, planning according to GOST was created in such a way that everyone could understand this process
Instructions
