A single-line power supply diagram is a document that conveys in a graphical form the operational characteristics and calculated data of the electrical network project of a particular room, whether it be a residential private or multi-apartment building, apartment, garage or enterprise. According to the documentation regulating the use of consumer electrical installations, the presence of the scheme under consideration by the person operating the electrical network is a fundamental point checked in the course of various kinds of approvals. Therefore, when designing this document, one should take into account not only the relevant GOSTs, but also the restrictions imposed by the regional offices of Rostekhnadzor and Energosbyt.
- What is a single-line power supply diagram and why is it needed
- Types of single-line electrical circuits
- Calculation scheme
- Executive scheme
- Design principles
- What should include a single-line power supply diagram
- Design stages
- Registration rules, GOST requirements
- Symbols used in drawing up single-line diagrams
- Programs for execution of executive documentation
What is a single-line power supply diagram and why is it needed
Single line electrical diagram - documentrepresenting the elements of the power grid of the power supply facility. It also indicates the technical characteristics of each element and the power indicators of the system (calculated and installed). purpose creating a linear diagram - to demonstrate a visual configuration of its components and connections between them.
The characteristic "single-line" as applied to power supply circuits means the image of communication channels that transmit energy, one line regardless of whether they are single or three phase. This graphical representation allows you to identify lines of force and to simplify the display of buses and control harnesses with multiple wires. This makes this type of diagram both laconic and informative.
Schematic diagram - this is drawing, which conveys complete information about the electrical, magnetic and electromagnetic connections of the system elements and the parameters of the components.
Types of single-line electrical circuits
Exist two main classes of circuitsdesigned at different stages of the project. To create an OSE you need to know key characteristics of each type.
Calculation scheme
Designed at the stage of document development on the project being implemented. It calculates the characteristics of the system and the required loads. Settlement documents may include into myself:
- schematic representation of the structure;
- function diagram;
- wiring diagram;
- drawing documents;
- fire safety scheme.
The electrical structure diagram shows the power elements (tie-in points, transmission lines, transformer components, etc.) and the communications between them. Function diagram is created to demonstrate the work of mechanismsinteracting with the power grid, and their impact on the safety of the facility.
It is usually applied for industrial premisesdealing with an abundance of dissimilar equipment. The installation project requires coordination with architectural and design solutions and a strict indication of wire diameters and equipment dimensions.
Executive scheme
Created when the room has already been in use for some time. It is required to graphically display the modifications that are planned to be made to the network structure. The document is prepared when replacing or modifying existing technical equipment. The executive scheme provides information:
- about the current state of the power grid;
- about the electrical appliances that are part of it;
- advice on elimination of malfunctions found in the course of technical inspections and other activities.
If you need to make a diagram of an enterprise, an apartment building or other object with several levels of supply, its do for each level: for example, for the entire plant, shop unit and its separate area. First, an image of the KTP and the networks connecting them is made, then the drawings for a separate KTP or electrical distribution board, and finally - all the individual shields presented in the room.
Design principles
When developing and drawing up drawings included in the OSE, you need strictly follow the rules of the PUE (electrical installation rules), as well as the requirements for this type of work indicated in the regulatory documentation. Before starting the process, you need to familiarize yourself with nomenclature of circuit elements.
What should include a single-line power supply diagram
The content of the single-line diagram is regulated by the normative documentation submitted to the applicant after consideration of the request for obtaining the technical specifications. In the project, the circuits must be indicated:
- framework of areas of responsibility supplier and consumer of electricity - they are presented in the text of the contract for the provision of services for the supply of premises;
- main distribution board and owned by the consumer TP with indication of automatic transfer switch devices (if any);
- autonomous power supply (if available);
- data on presented in the room distribution cabinets both lighting equipment and power lines;
- horizontal dimensions of main power lines, the models used for communication cables and how they are laid;
- calculated data on energy losses during transmission;
- intelligence about emergency mode work;
- equipment for electricity metering with the designation of the transformation ratio (if a secondary electric current of 5 A is used);
- technical characteristics of fuses, automatic switch-off devices;
- intelligence about loads with notes on their power in kW and current strength.
The drawing, developed taking into account the given data, later can be supplemented with additional graphical representationsnot subject to special approval.
Design stages
The stages of development of a single-line diagram have a certain sequence. First, the applicant is required to request execution to a company providing power supply services, for the issuance of technical specifications for the implementation of this task. After waiting for the receipt of the documents regulating the process, the representatives of the consumer preparing a project schemes for these technical specifications. Designed by the drawing is agreed with the company, which issued the technical specifications.
If, during the operation of the electrical network, it becomes necessary to make changes to the configuration of its elements, is being prepared executive scheme... The sequence of steps will be identical for her.
Registration rules, GOST requirements
State standard numbers:
- 2.721-74 - introduces graphic symbols in schemes;
- 2.755-87 - describes how to label switching devices and contact connections;
- 2.709-89 - talks about the symbols of the wires;
- 2.710-81 - signs that combine letters and numbers.
Symbols used in drawing up single-line diagrams
The visual representation of the various elements that make up the power supply system is regulated by regulatory sources. Boxes, shields and cabinets have their own designations in drawing documents:
- Shields are shown by rectangles. Trunk shield elements have a horizontal line cutting off a small fragment at the bottom. The group elements responsible for the working lighting are filled with black paint, for the emergency - they have two diagonals.
- Single panels and cabinets one-way service are represented by squares with a horizontal cut-off fragment at the bottom. Bilateral service items have cutoffs at the top and bottom. This rule also applies to elements from several panels, only they are presented in the form of a corresponding number of squares arranged in a row.
- Broaching box has a square shape. The opening box is represented as a square with a thick vertical line through it.
- Junction box depicted as a circle with a thick cross line and a vertical downward from the center of the circle.
Conventional switch looks like a circle with a line extending from it to the right and up. Number of poles (one, two, three) is demonstrated by the number of small vertical bars at its end. If it is supposed open installation, dashes are drawn from the base to the right and down, and in the case of hidden it is crossed by transverse lines. Have double and triple elements instead of one line, there will be two or three. High degree of protection shown by filling the circle with black. If the item works in two directions, the second line is drawn to the left and down from the circle.
The socket outlet is shown as a "recumbent" semicircle with a line extending upwards from the top. The presence of two poles is described by the second similar feature, the protective contact - additional horizontal, hidden installation - going from the center to the top. Strong defense is shown by shading in black.
Designations lighting fixtures:
- Luminaires with fluorescent lamps are shown with rectangles elongated in length, the rest of the devices - with circles.
- Cable depicted by a transverse dotted line and a bold line under it near the "equator" of the circle.
- Outdoor lighting devices show the letter "T" overturned on its side, growing from the left side of the circle.
- Chandelier shown by dividing the circle into 6 segments.
- Wall lamp holder - a blackened triangle with a V-shaped fork at the top.
- Pendant chuck - a circle crossed out by diagonals. Ceiling - similar, but the strikethrough elements that are within the shape are not applied to the image.
- Ammeter, voltmeter, galvanometer - figures of a round shape, with the letters A, V and an upward pointing arrow inside, respectively.
- Temperature sensor and oscilloscope - squares. The first has a t inside and an arrow pointing to the right coinciding with the base. The second has a thin N-shaped image of lightning.
- Electricity meter - a high rectangle with a separated upper segment and the inscription Wh.
If the designer of the circuit has doubts about how to depict this or that element, he can familiarize himself with the nomenclature of OSE symbols in the reference literature.
Programs for execution of executive documentation
There is no need to draw a diagram by hand on paper to draw up high-quality documentation that meets state standards. You can draw online, using the sharpened for this purpose software.
Application examples:
- MS Visio - It is widely used for all kinds of office work and is suitable for preparing a drawing of an electrical circuit of a residential building;
- Compass-Electric - a simple program, freely distributed, used by employees of power supply services;
- 1-2-3-Scheme - an option often chosen by students and inexperienced professionals;
- AutoCAD Electrician - a popular program among professional developers.
Choice a suitable program is being done taking into account the scale and complexity of the network... For example, for a private house there is no need to use complex professional software.
