Low-voltage networks are an element of the building's engineering system. In principle, almost any cable network can be called low-current if not power, but information currents are conducted through the cables, the voltage of which ranges from 12 V to 24 V, and which change exclusively in milliamperes.

Requirements for low-current networks

Among the main requirements that modern low-current networks must meet today, it is worth highlighting:

• Extremely high reliability.
• Stable work without all sorts of failures or errors.
• Relatively low cost for installation and operation.
• Scalability.

Thanks to the possibility of using low-current systems, today it is possible to provide almost any type of communication, as well as to ensure the normal functioning of computer networks. Depending on the purpose of a particular network, as well as where it will be used, they are all subdivided into commercial and household.

What are they needed for?

Using low-current networks, you can do:

• Reception, as well as subsequent distribution of both terrestrial and satellite television.
• Providing access to the telephone network.
• Normal operation and provision of access to the global network.
• Registration of wire broadcasting networks.
• Normalization of the effective work of security and fire systems.
• Normalization of the effective operation of warning and alarm systems.
• Use of access control systems to various objects (automatic control of barriers, gates and turnstiles.
• Fully automated accounting system for managing various energy resources (water meters, electricity meters, home automated systems).
• Work
• Interaction between intercom.
• Complete structuring of cabling systems.

Mounting

Before the installation of low-current networks is carried out, a full-fledged project of the future network is initially formed and, in particular, the future location of the shield, relays, sockets, as well as all other nodes that will be included in this system is precisely determined. Placing all kinds of cables, installers perform all work in accordance with specialized rules, as well as approved standards.

What is included in the installation?

The installation of low-voltage networks itself includes: laying telephone, computer or television lines, installing specialized information sockets, as well as other intercoms, video surveillance, security and fire alarms and other equipment.

rules

At the same time, there are several important rules that must be followed without fail when laying low-current networks:

• The minimum distance at which parallel power and low-current cables should be located should be at least 0.5 m, and if they intersect, then the angle of intersection should be 90 °. The distance between the laid Internet lines, as well as specialized power cables, can be less than this distance, because they are not affected by any interference during the transmission of digitized signals.
• In no case should low-current cables be led into a riser in which other electrical wires are placed.
• Splicing wires is prohibited. Cable routing must be carried out exclusively with solid wires.
• In the event that the nets are laid in one direction, they must be laid in parallel and at the same time tightly pressed against the other.
• If the device of low-current networks and systems is not in a hidden wiring, then in this case the minimum distance at which they are located with the telephone network cables should be at least 15 mm if the line length is 10 m.
• The junction box should be located directly on the wall, but do not forget that it is strictly forbidden to place it over doors, windows or various openings. The minimum permissible distance for the junction box to be positioned on the wall relative to the ceiling is 300 mm.
• Cables of different capacities that intersect with each other should be adjacent to the wall or should bend around it from above or below, depending on what capacity these cables have.
• It is imperative that in the process of laying cables, it is necessary to provide for their protection. In particular, external low-current networks, which are installed under windows or downpipes, require this, since they are the most susceptible to various damage and for this reason provide for the use of metal linings.
• Any low-current lines of networks must be grounded using a specialized bus, which is made up of carefully insulated copper conductors. Such conductors are used to connect the junction metal box directly to the earth line itself.
• If the project of low-current networks provides for the open laying of telephone network cables, then in this case they should be at a distance of at least 200 mm from the floor, and should be at a distance of more than 150 mm from the ceiling. If we are talking about a closed method of laying, then in this case the cables can be at any convenient height for this.
• In the event that various digitized signals are transmitted through the network lines, then low-current electrical networks can be located along the walls in grooves, specialized PVC sleeves in the raised floor or floor screed, and can also be suspended above the false ceiling.

Not sure how to do it? Trust the professionals

The design of low-current networks, as well as their subsequent installation, should be carried out only by qualified specialists who have long experience in this field. Indeed, depending on the literacy and quality of all work, it will directly depend on how well the signal and communication pass, as well as how reliable and durable the operation of all equipment will be. In addition, the quality of low-current work also affects the safety of the equipment during its operation.

Telecommunication equipment

The use of telecommunication equipment occurs in almost any case when the laying of low-current networks of various types of data is carried out, and communication is also established between several devices. In this case, the quality of the equipment used and materials that will be present in the process of building low-current networks directly depends on how correctly all

Telecommunication equipment includes two main elements.

Passive network equipment

• A set of connecting cables, which includes fiber optic cable and twisted pair.
• Connecting components, as well as a patch cord for connecting various devices to each other.
• Patch panels, including cross-panels for cable routing and direct clamping of cross-over units, and a patch panel for signal wiring in the rack and cabinet.
• Cable as well as panel connectors for signal transmission. The use of these elements is also found in patch panels, and depending on how many contacts are present, all types of such devices are divided into two-pin and three-pin.
• Information sockets equipped with modular connectors and designed to be installed in cable ducts.
• Modular jacks that are used to form cable networks, as well as a complete set of telecommunication outlets. These sockets are included in modular panels and outlets. In order to connect active equipment, the technology of displacement contact through insulation is used, while, depending on the cable used, sockets of various categories can be used.

Cable boxes

• The distribution cabinet, which is located directly inside the room and is used to connect wires to the cut-in contacts of the plinths, as well as to provide the termination of cables.
• Instrument racks that are used to house and integrate various devices in digital broadcasting systems.
• Cable boxes, which are installed in the places of transition to overhead communication lines. Such boxes are used as effective protection of cable lines from all kinds of external influences or overvoltage.
• Distribution telephone boxes that provide switching of connecting wires in communication systems.

What cables are used in such networks?

For a full-fledged laying of a computer, television or telephone network, different types of cables are used.

If we are talking about laying low-current computer systems and networks, then in this case, copper cables of the "twisted pair" format from category 5e and 6, belonging to class B and E, respectively, or specialized fiber-optic cables are used.

If you need to lay telephone networks, then in this situation it is quite enough to use standard low-current cables of the 3rd category. At the same time, when installing low-current networks, it is necessary to use electrical cables through which data transmission can be carried out at a clock frequency of up to 1 MHz. The use of optical cables is most often encountered when it is necessary to lay backbone networks, since their use is caused by the need for an extremely high data transfer rate. The cable brand is initially indicated in the installation diagram.

How are the networks laid?

Depending on how the cable is placed, low-current networks can be laid:

• Underground... In this case, cables are laid in specially designated underground utility lines, which are also called cable ducts.
• Over the ground... Here, cables are thrown through the air from one house to another, or in those places where the wires are suspended on power lines.
• Closed way... Cables are laid in specially designated trays in order to exclude the possibility of causing any damage to the network.
• In an open manner... This option of laying is provided only if there is no possibility of causing any damage to the network.

In the process of choosing a cable, it is quite important to take into account not only where it can be used and what technical characteristics it has, but also pay attention to ensuring that the entire network meets the fire safety conditions.

conclusions

If you are not versed in the field of wiring, then you should not even try to carry out all the work completely yourself. It is much better if all procedures, starting from the selection of cables and ending with the subsequent installation of the entire system, including the maintenance of low-current networks, will be carried out by qualified specialists who have been professionally working in this area for several years and know all the subtleties of such work.

Each of us knows that all electrical appliances in the house operate on a voltage of 220 V. This is a high enough voltage, requiring high energy consumption and can seriously injure a person.
But there are also a number of devices and systems that do not require high voltage. Such electrical appliances are called low-current systems.

All household electrical equipment is designed to perform fairly complex processes and needs high currents. For low-current systems, this is not at all a prerequisite. The main area of ​​application of such systems is data transmission devices:

• the Internet;
• telephone communications;
• various alarms and video surveillance;
• TV.

The mechanism of operation of information transmission systems is simple: data encrypted with a special code is transmitted at high speed and using low voltage.

Types and scope of low-current systems

Along with the already listed household applications, low-current systems are used in industrial conditions, such as: automated electricity metering, cable systems, computer networks, switching devices (ATS), etc.
According to the role of application, the systems under consideration are custom and commercial.

Among the most popular and most important for life are the Internet and telephone communications. Thanks to telephony, each of us is able to easily contact the desired subscriber at any distance. Connection to the World Wide Web can also be carried out via telephone wires, but in this case the connection speed will be low, therefore, the most relevant for the Internet is the use of fiber-optic wires, which have a higher data transfer rate.

Television transmits the picture via cable or by radio waves. To carry out this type of information exchange, satellite and household receiving antennas are required.
Video surveillance includes a wide range of devices designed to control small (apartments and offices) and large (industrial) premises and buildings.

Various types of alarms are responsible for many types of security. Most types of warning systems are based on motion sensors or circuit breakers. If an intruder entered the building, the sensors transmit information to the security console. The fire alarm system works in a similar way; heat and smoke become a factor in its triggering.
All low-current systems listed above are designed to create a comfortable and safe life. They do not require high currents, and therefore they are harmless to health and economical.

Installation of low-current systems and documentation for it

Low voltage systems are invaluable and useful helpers in our daily life. Failures and malfunctions in their work sometimes cause great inconvenience. To prevent such annoying problems, it is very important that the design, installation of SCS and maintenance of such systems is carried out only by specialists of the appropriate qualifications.

All basic and necessary requirements used for the design and installation of low-current systems are spelled out in the following list of documentation:

• GOST 21.101-2009. General provisions for the preparation of design documentation used in construction;
• SNiP 3.05.06-85. Preparation, implementation and commissioning of electrical work;
• RD 78.36 002-99. Recommendations for the use of security and warning systems and their designation;
• PUE 7. Requirements for electric lighting of premises;
• RD 78.145-93. Preparatory, installation and commissioning works of warning and signaling systems;
• NPB 105-03. Classification of premises and buildings according to the level of fire safety.

Any of the low-current systems, being installed according to the rules of this documentation, will become the key to safe and comfortable human life.

The project of low-current networks of the enterprise. IOS Section 5

The project of low-current systems of the enterprise includes the following networks:

Structured cabling system (SCS)

This low-current project provides for the connection of workplace equipment (telephones, desktop computers and other active equipment) and network equipment into a single local computer network of the enterprise. All connected points are located in the premises, in accordance with the reconstruction plan. The project is foreseen on active switches Cisco third level with the possibility of stacking(connection of switches with a high-speed bus, combining them into a single complex)... The main cross-section of the building is envisaged in the ATS room in the building 3 room. 285 m. Horizontal crosses are located in the corridors of the buildings in wall cabinets installed at a height of 2.3 m from the floor level. The network topology is star.

The SCS provides the ability to connect both existing analog telephones and the ability to connect I. P ... telephony. To connect I. P ... telephony needs modernization of PBX - installation of additional I. P ... modules. Modernization of automatic telephone exchanges is not envisaged in this project. The project provides for the phased replacement of the old telephone network with a modern structured cabling system. The developed system is designed with a reserve for subsequent expansion and integration with other engineering networks.

CCTV system (SOT)

Security television is used for centralized monitoring of technological equipment.

Building 5 provides for the installation of the system IP video surveillance.

The following video fixing devices are used I. P. camcorders:

to record the movement of people, the operation of technological equipment in the test hall, it is planned to install stationary video cameras B03618FIR. The cameras have a day / night function, which allows high-quality image capture at illumination up to 0.05 lux. Camcorders record with a resolution of 1280x960 p ., 25 fps. Video cameras are installed in sealed thermal housings with dust and moisture protection IP66.

Camcorders are mounted on brackets to the walls.

As the receiving equipment providing recording, compression, and storage of video, processing and the possibility of software analysis of the video archive, the software and hardware complex of the company is provided. Macroscop ... The video server is installed in the main distribution frame in the building of 3 rooms. 285. The video server is installed with the ability to connect up to 32 video cameras, with the calculation of the reserve and transfer of the existing CCTV system to IP technology to improve the quality of video recording and data processing.

Video signal transmission is provided via twisted pair, using the power of the SCS section of this project.

A twisted UTP cable 4x2x0.52 is used as a cable for video signal transmission from the camera to the SCS hardware cabinet cat .5 e 4 p , manufacturer "Parity".

Power supply of video cameras is carried out according to the 1st category, through the provided uninterruptible power supply, installed in the cabinet according to the SCS project. The UPS provides a system runtime of at least 30 minutes. Power supply of video cameras is carried out through the switch Cisco with POE technology , powered by signal cable. These switches can also be used to create additional workplaces.

The video surveillance system incorporated in this project is modular and has the ability to expand and upgrade. The operator's workstation can be performed at any workstation connected to a structured cabling network. The software for the operator to work with the system is free, the number of operator jobs is unlimited by the system at the software level. The project assumes two operator places in building 5, room 3 (observation cabin) and in building 8, room 100 (security post). Workplace equipment: PC, monitor, peripherals - the project is not provided for and there are no special requirements for the equipment.

System of Universal Time (CEB) project

The system synchronizes the set clocks from the GNSS GLONASS and GPS NAVSTAR satellites with an accuracy of no worse than ± 100 μs, and provides automatic transition to winter / summer time.

The system allows you to synchronize time and date on computers connected to the enterprise LAN.

The system is self-healing.

There are five main beams from the clock station through free pairs in the SCS to buildings 1, 2, 5, 9, 11, respectively.

The following are adopted as secondary clocks in the project:

- watch SVS-40 with a panel diameter of 400 mm, one-sided, classic design.

Loops of synchronization and control of the secondary clock are made with a twisted pair cable KSVVG 1x2x0.75.

The station has its own backup battery. That will allow her to keep the entire system working for at least 4 hours in case of a power outage.

The clock system is a consumer of category I electricity, its power supply is provided from two independent power supply sources:

· main input: ~ 220V, 50 Hz.

· backup input: from a 2200 VA uninterruptible power supply installed in the cabinet in the SCS section in the cabinet.

The power consumed by the clock system does not exceed 100W

System cables and wires are laid:

- according to the provided cable-supporting structures in the SCS section of this project.

- in rooms and corridors without false ceilings - in TMS minichannel 22x10 mm.

- in rooms and corridors with a false ceiling - in a PVC pipe with a diameter of 20mm

- through partitions and interfloor ceilings to a water and gas pipe with a diameter of 25 mm.

Access control system (ACS)

The project provides for an access control and management system of the "vestibule-gateway" type and control of the passage through the reader to the entrance and exit.

The basic principle of operation of the Tambour-Gateway ACS is that it is prohibited to open the door included in the gateway until all other doors are closed.

To implement this logic, the equipment of the company "Bolid" was adopted on the basis of C-2000-2 controllers. These controllers have a standard function "Tambour-gateway" for two doors (see the equipment passport).

To enter the "vestibule-gateway" contactless readers are used, to exit the vestibule there is a button.

To exit in case of an emergency, emergency buttons "Exit" are provided, which physically cut off the power of the electromagnetic locks.

For local control of the system, the existing C-2000 console is provided at the security post in building 8.

For centralized control of the system, a cable with an interface is provided. Rs -485, using the reserve in the SCS for a free pair.

Switching network controllers using the protocol RS -485 indoorsprovided by cable ParLan F / UTP Cat 5 e. ng (A) - HF 4 x 2 x 0.52 (Ethernet).

Connection of devices is provided by the signal cable KSVVng- (A) -LS 2x0.8 and KSVVng- (A) -LS 2x0.4

Install the cable in the rooms and in the corridor in the cable channel.

Network controllers are mounted on the inside of the protected premises to provide protection against unauthorized access.

Power supply of control panels is carried out according to the I category of power supply.

System cables and wires are laid:

- in office and household premises without a false ceiling - in a 10x22 cable channel;

Burglar alarm (OS)

The burglar alarm is designed to detect unauthorized entry into protected premises and transmit a notification of unauthorized entry to the round-the-clock duty post in building 8, room 100, for the purpose of timely notification.

The premises, according to the plan of reconstruction and technical re-equipment, are planned to be equipped with:

- volumetric optical-electronic, addressable detectors of the S2000-IK type isp.02, for the protection of the internal volume of premises.

- magnetic contact, addressable detectors of the S2000-SMK Estet type, for the protection of doorways.

As the equipment for receiving signals about the triggering of security detectors, a control and monitoring device of the "S2000-KDL" type is used, which, according to the existing RS 485 interface projected in 1060-2011-2P-PB, is connected with a symmetrical cable to the "S2000M" monitoring and control panel installed in the security room in building 8, room 100. The RS-485 interface is common for burglar alarms and fire alarms.

The addressable burglar alarm loop is carried out with a KSVVng (A) -LS 2x0.8 cable and is connected directly to the control panel.

Arming and disarming is carried out by an arming / disarming command received via the RS-485 interface from the S2000M control and management console.

Receiving and control devices are installed in ShPS cabinets with built-in uninterruptible power supply units RIP-12RS. Cabinets are taken into account in the project 1060-2011-2P-PB, and have a reserve.

Signaling cables and wires are laid:

- according to the provided cable-supporting structures in the SCS section of this project.

- in office and household premises without a false ceiling - in the minichannel TMC 22 / 1-10,

- in rooms and corridors with a false ceiling - in a PVC pipe with a diameter of 20mm

- through partitions and interfloor overlap in a water and gas pipe with a diameter of 25 mm.

The power supply of the designed control and monitoring devices "S2000-KDL" is carried out according to the I category of power supply through the RIP-12 RS redundant power supply units with rechargeable batteries provided for in the PB project

Intra-facility warning system (SVO)

The projected on-site warning system is a universal system and serves for:

I. Transmission of civil defense and emergency signals. *

II. Alerts people about fire, automatic voice message and audible tone. *

* I - III priority level

The installation of the system is carried out in rooms subject to reconstruction and technical re-equipment.

Voice messages are entered from the META 8581 control panel and the META 9401 main alarm control device. The project provides for 1 control panel installed at the security post, building 8, floor 1, room 100.

The choice of loudspeakers and their installation locations are determined taking into account the area of ​​the premises and the operating noise level. The project uses the following types of speakers:

Wall speakers АСР-3.1.5 maximum power 3W. They are installed in premises subject to technical re-equipment and reconstruction, in accordance with the plans.

To ensure independent reportingand receiving signals from civil defense and emergency situations, the project provides for the installation in the premises of the administration of subscriber loudspeakers of the type " Meschera AG-01 "with a power of 1 W.

To provide the enterprise with city radio broadcasting, the project provides for the installation of a radio rack and a subscriber transformer TAMU-10S on the roof of the building 3.

Provide grounding of the pipe support with a metal wire with a diameter of 4 mm. The connection of the pipe stand to the city radio broadcasting is carried out as a separate project.

Connect to the city radio broadcasting network in accordance with the technical conditions for connection from FSUE RSVO No. 481/457 dated 17.04.2014.

Power supply of the points of the radio broadcasting network is provided from the transformer installed on the radio rack on the roof of the building 3.

The audio loop and the radio transmission cable are made with a 1х2х1.5 cable KPKVng (A) -FRLS 180

Cables and wiressystems are laid:

- in office and household premises without a false ceiling - in a 22x10 cable channel;

- according to the provided cable-supporting structures in the SCS section of this project;

- in rooms and corridors with a false ceiling - in a PVC pipe with a diameter of 20mm;

- through partitions and interfloor ceilings to a water and gas pipe with a diameter of 25 mm;

All electrical networks of buildings can be divided into 2 large categories - power and low-current. AC voltage in the range from 220 to 380 V, as well as current from 1 ampere and above, passes through power networks. These wires are essential for office equipment and other equipment.

Nevertheless, there will be no sense in this equipment if, at the same time, a clear informational interaction of all office equipment is not organized, and its integration into a specific structure (branches, communications, the Internet, etc.) is not ensured. It is this task that low-current systems perform, which differ from power systems by a lower voltage in the network. As a rule, this voltage does not exceed 24 V. However, in reality, systems with voltages up to 60 V.

Low-current systems differ from power systems by one more factor - a high concentration of "information flow". For a company ordering the performance of low-current work, it is very important to foresee all the functions in advance, having laid them down at the design stage. While the company is still not so large, the need for some of these functions will be absent, but they will definitely be in demand as the organization develops. Accounting for all functions will allow the company to save its financial resources, since their subsequent integration into the already installed system will cost the company an order of magnitude more than the initial one.

The composition of low-current systems includes:

• Telephone communications.
• Structured cable networks (equipment required for the operation of local area networks).
• Security and fire alarm systems.
• Internet access.
• Video surveillance system.

However, if desired, low-current systems can provide several additional functions, including:

• Devices designed for negotiation - intercoms, selectors and automatic telephone exchanges.
• Energy resource management systems, as well as automated accounting systems.
• Access control and management systems (card readers, electronic locks, barriers, gates and turnstiles).

The use of low-current systems greatly facilitates the control and management of critical processes in the company, as well as improves the transfer of information. They can be used for a very long time without requiring replacement or modernization. At the same time, each company always has the opportunity to increase some elements of the CC without resorting to making changes to the current systems.

Even in spite of the necessity of expenses for the installation of CCs, in the long term, these investments are justified, and the positive result from using CCs is felt already in the first days after the completion of their installation.

Installation of low-current systems is a complex process, on the correctness of which the functioning of the company and the speed of information flow largely depend. The importance of these systems is so high that there can be no talk of any savings. It is necessary to use only modern equipment, the best technologies and involve experienced and professional workers in the installation process.

Low-voltage works include installation of video surveillance systems, office telephony, local area networks, security and fire alarms, as well as access control systems.

Local networks. The work of not a single company and not a single office can be carried out without the organization of a local network. It includes peripheral equipment, telephones and computers. The first stage of the installation of this system most often begins before the requirements of network users are known regarding the type of network flow and the speed at which data transfer should occur. Installation of a local network creates the basis for a computer network, which is further combined with a telephone network. Both of these networks, when integrated, create a local network.

CCTV. Thanks to low-current work on the installation of video surveillance systems, it becomes possible to control and visually observe all areas of a building or office. In addition, the installed video cameras allow online video recording, which increases security several times and protects the company's property from possible theft.

Office telephony. Reliable high-quality telephone communication in the office and outside it is ensured by means of office telephony - mini-automatic telephone exchange, departmental automatic telephone exchange and automatic telephone exchange for the office. Installation of office telephony increases the efficiency of its use and reduces the cost of its maintenance. It is due to the ease of use, high-quality communication and affordable prices that mini-PBX is so popular. Now you are not threatened to hear noise in the telephone receiver or to struggle with constant interference. The main thing is that the installation of office telephony was carried out by professionals, taking into account all the rules and regulations.

Access control systems. Installation of access control systems allows you to effectively determine the time spent by staff in the office of the company and control the work of employees, as well as to impose restrictions on access to individual office premises.

Thanks to the installation of access control systems, a database is organized for each client and visitor, access control to office premises is ensured, a competent record of the employees' working time is maintained, and other important tasks are solved.

Security and fire alarms prevent undesirable persons from entering the office, and also notify emergency services in case of flooding or fire.

Wi-Fi