Single-line diagram: a sample, how to draw, types and stages of power supply design

Electricity supply is an important component of modern buildings and structures. In this case, wires and other electrical equipment must be located in the right places and meet certain requirements. Various schemes and projects help to understand this. One of the most important and irreplaceable among them is the single-line electrical supply diagram.

Features of power supply

The value of a linear circuit can hardly be overestimated. It is also the preferred option in many cases. It displays items of particular importance such as:

• the number of operating loads;
• power levels;
• marking and designation of electrical panels;
• ratings of circuit breakers.

And this is far from the entire list of nodes included in various parts of any electrical network. After all, each linear power supply scheme contains calculations from the input of the power line to the smallest consumer.

By themselves, such schemes can be considered as a simpler analogue of the principle, where all the designations are made in the form of lines. And it does not depend on the number of phases and wires. This option is extremely convenient to use, even for a non-professional, while being functional and effective.

For more convenient use in terms of application, a single-line power supply diagram can be of two types:

1. executive;
2. calculated.

In essence, there are no particular fundamental differences between them, with the exception of the purpose of each of the types. An example of a single line diagram can be seen in the figure:

Executive view

Executive "one-rulers" are developed in cases when the entire network, including electrical installations, is already assembled and functioning. Its purpose is rather necessary to identify shortcomings and violations and is used in the modernization and recalculation of the power grid. It also allows you to determine the location of the supply line.

When drawing up such a document, the following information must be displayed:

• all devices and consumers included in the network;
• network status;
• shortcomings identified in the process of research and development of the single-line diagram.

Calculated one-line

The situation is different with the calculated version. Although all displayed elements look the same, the very purpose of such a scheme has a radically different function. Here, the design starts when the building is ready for electrical installation and the load data is available.

Thus, the design diagram displays the ratings of the protective nodes, the number of cores, the footage and the cross-section of the cables, the location of the boards and input-distribution devices, as well as all the powers and sizes of the power equipment.

Classification of circuits

In addition to the two types, "one-line" can be divided into qualifications. After all, they, in addition to the main functionality, display various divisions of planned or existing systems.

In this regard, it is customary to divide them into the following types:

• Structural, which show the general picture of the power grid and installations.
• Mounting - are coordinated with architectural nuances, indicating all the exact data on cables, equipment dimensions, fasteners and others.
• The schematic diagram of the power supply is carried out according to the state standards of a particular country.
• Functional - used in cases where there is a large number of different consumers (machines, machine tools, equipment), and display an overall picture of the network and the interaction between mechanisms, power supply and each friend. They also help to assess the overall safety.
• Special - Displays the projected parts individually.

Self-development

It should not be difficult to draw a single-line power supply diagram on your own, even if this is done for the first time. The main thing is to comply with some basic requirements so that the resulting drawing is understandable and carries the maximum of useful information.

All designations and general appearance must comply with GOST 2.702-75. The first three phases are applied to the drawing, which involve powering the entire line. The next step is to determine the lines of group units that will depart from the main supply. Special detailing is not required here, since the "one-line" should only reflect the general state of affairs.

According to all the same GOST, it is necessary to properly designate all the components of a single-line power supply diagram for a workshop, apartment, office or other premises. These are automatic machines, RCDs, contactors, switches and other parts of the electrical network.

It is recommended to pay special attention to the number of outlets, switches and other points. As an example, a typical layout of an office, house, apartment or other similar object was chosen. Any of the schemes must include the following information:

• point of connection to the input network;
• input distribution equipment;
• device and its brand;
• parameters and data of the shield;
• the cables used must be displayed with all information, including length, grade and cross-section;
• rated and maximum currents of devices located in the circuit;
• approximate design loads (may differ depending on the requirements for the facility).

Since all the basic requirements are put forward by the company managing the power supply, it is preferable to immediately pay attention to all, even very small and insignificant elements. After all, the created single-line diagram is an extremely important document, the responsibility for which is borne by more than one party.

If it is decided not to pay people involved in the development of such schemes, but to do everything independently, then you will have to acquire a Unified System for Design Documentation (ESKD). How to implement a project - no special requirements. You can draw the old fashioned way using a ruler and pencil. Or in a more modern way, using a computer and a well-proven AutoCAD program.

If you cannot complete the project yourself, then there is always the opportunity to contact the specialists from the design bureau. They will do this job quickly and professionally.

Design stages

If, nevertheless, it is decided to do the project with your own hands, then you will have to find out the sequence and stages of such work. It may depend on whether it is approved or not. Therefore, you need:

1. Get technical specifications, which will make it possible to find out where the point is where you will need to power. The municipal power grid organization will help here.
2. Obtain a master plan from the municipal department of architecture in order to have an idea of ​​the path where the power cable runs to the private power area. This will also help to find out where the substation is located, as well as other communications that can be damaged without such a plan.
3. Calculate the power required by the consumer. And already on the basis of this, make a single-line diagram. Such a project in itself should contain not only the scheme itself, but also materials that will help to understand it, i.e. symbols, explanations, connections of consumers and protection devices.
4. To agree on the developed project, which will be a confirmation of the permission to connect to the mains of the power grid. This is the final stage, after which the installation work can begin.

Here it is worth noting that it is forbidden to start any installation work until you receive the appropriate permission from certain authorities. When such permission is received, then all responsibility is shifted to the installer.

Often, when developing a project, additional lighting or security systems slip out of sight, i.e. cameras, alarms, video surveillance, etc. But they also need to be included in the overall project. If the project fully complies with the stated requirements, then there will be no problems with the approval and obtaining permission to connect and perform installation work.