The length of low-voltage networks for various purposes in modern homes is calculated in kilometers
Video intercoms are connected to a separate low-current line, but can be integrated into a structured system
Low-voltage devices are switched in special cabinets located on stairwells. Wires and cables are pulled into cabinets through riser pipes
Low-voltage control devices for security alarm systems, video surveillance, a network server in apartments are placed in places inaccessible to unauthorized people
Low-voltage wires and cables are pulled into apartments through specially provided holes in the wall.
When laying power wiring and low-current cables in trays, the distance between them
To avoid interference and mechanical damage, some low-current cables are enclosed in a metal hose
Distribution points are mounted both outside the apartment and inside it, if required by the safety of the operation of security systems, alarms, video surveillance, special communications
Low-voltage cables can be laid in PVC pipes
Low-voltage wiring made in an open way is hidden behind hemmed plasterboard walls and ceilings
For the convenience of laying a large number of wires in technical rooms, metal trays are used.
A household video camera built into the peephole of the door is connected to a low-voltage network or to a VCR. The wire is laid under the door trim
Grounding buses for low-voltage networks are made as thoroughly as grounding buses for electrical wiring
Concealed wiring to low-current devices requires accurate knowledge of their installation locations specified in the project documentation
For ease of use, television and telephone sockets are combined into a block with sockets for household electrical appliances according to the principle of modular installation.
This ground wire is connected to the ground line by isothermal welding. The connection point is protected by a casing made of fire-resistant plastic.
Low current networks
Few of us think about what is the purpose of wires and cables, no one knows who and when transferred from one roof to another, pulled into underground sewers.
We will talk about low-voltage networks that provide cable television, wired radio, telephony and the Internet, fire and security alarm systems, automated energy metering, local computer networks, and intercoms in residential buildings. Since there is no monopoly on commercial activities related to the provision of services by wire to the consumer, various organizations create their own low-voltage networks, pulling wires and cables both over the air and underground. The laying of underground communications is much more expensive and in the conditions of the city is not always possible. Therefore, wires of low-voltage networks are often hung on power line poles and transferred from house to house. This is also done when laying the main fiber-optic communication cables, through which signals are transmitted in the form of light pulses. If it is impossible to stretch the wires to the object by air or underground, the signals are transmitted using radio channels.
The equipment of «smart home» systems, multi-rooms, home cinemas is mounted in cabinets placed in specially designated rooms. AT
Entering the building through the attic or basement, low-voltage wires and cables are brought into a riser specially allocated for this purpose, which is two or more inch steel pipes, and stretch to distribution points. These items take the form of mounting panels or cross-countries, which, in turn, are placed in floor or wall cabinets and racks. AT
Now the relevance of low-voltage networks has increased dramatically, since the mayor’s offices of large cities have adopted a number of promising programs for the creation of automated accounting systems for energy resources and urban Intranet networks. The transmission of signals in them is carried out mainly by wires. Thus, in Korolev, near Moscow, the efforts of a specialized municipal organization and its dealer have practically completed the commissioning of the city’s Intranet network. Its subscribers enjoy free Internet access to local information resources, make appointments with doctors, pay bills and
Which organizations have the right to install low-voltage networks in houses, what are their rights and obligations, what responsibility do they bear to the customer and the administration in charge of the house? Traditionally, the rights to carry out this kind of work are held by city communication centers (they are in charge of telephony and wired radio broadcasting) and municipal enterprises that ensure the operation of television antennas and cable television networks. These organizations have licenses from the Ministry of Communications to carry out work in the field of low-voltage communications. The performance of work is preceded by the conclusion of an agreement with a private person, if it is a telephone or a radio point in an apartment, or with a legal entity (ZHEU, DEZ or other operating organization), if this is the installation of a common house cable network. AT
benefits of structuring
The day is not far off when the disparate low-voltage networks of apartment buildings will be combined into structured cabling systems (SCS), as is done in modern offices. What is SCS? It is a universal building/campus telecommunications infrastructure designed to transmit all types of signals, including voice, data and video. SCS may also not function in the entire building, but only on a separate floor or even in an apartment.
SCS is built in such a way that through each interface (connection point to the system) you can enter any of the interconnected networks. For example, to receive a video film, a TV program from the network, or to talk on the phone. At the same time, two lines are sufficient at the workplace. To
With all the advantages of SCS, it has a significant drawback: it is still expensive. So, for the normal operation of the network, it is necessary to lay in it a reserve for subsequent development. These are additional cells in cross-connects for connecting wires and cables, and signal amplifiers used when building cable lines, and cables with higher characteristics to ensure the operation of more devices, and much more. So far, this pleasure costs 3-4 times more than the installation of individual low-voltage networks.
Already today, the growing automation and internetization of the housing stock requires designers to make high-tech solutions. Meanwhile, the SNiPs, GOSTs, TUs and other regulatory documents that are extremely necessary for this are practically absent in domestic construction.
Thus, cable connections on the Internet are mandatory tested for compliance with international ISO / IEC standards.
what to connect, where to insert?
Although there are not enough regulatory documents on low-voltage networks in our country, «the tree of life is lushly green.» Experts are guided by any documentation. Both in domestic and foreign practice of laying telephone cables and installing subscriber wiring, installers of low-voltage networks follow the rules, which are not much different in foreign and domestic manuals. According to OSTN-600-93, the distance between the telephone cable and parallel insulated wires of lighting or power wiring should be at least 25
It is forbidden to run low-current wires and cables into the electrical wiring riser, since if unbalanced electric currents occur in the power or lighting wiring, they may enter low-voltage networks. BUT
The route of telephone subscriber wiring laid in an open or hidden way (from the junction box to the telephone set) must meet the following requirements:
Wiring to the terminal device should be carried out with a solid wire, splicing is not allowed. Telephone wires running in the same direction must be laid in parallel, close to each other. When a telephone cable is introduced into the house from a rack on the roof or from a pole, it is necessary to install a subscriber protective device (AZU) in close proximity to the place of entry into the house (usually in the attic), which must be grounded.
A wired broadcasting network (its presence in houses is mandatory according to the rules of the Ministry of Emergencies), as a rule, is carried out by hidden wiring (in partitions, walls, ceilings). AT
As for cables for working with equipment designed for high-speed information transfer (digital television, Internet, IP-telephony), they can also be laid within the apartment in both hidden and open ways. Hidden wiring in this case is carried out in PVC sleeves under the raised floor and in the floor screed, behind suspended and hemmed ceilings, along the walls in strobes. Low-voltage sockets with two or more telecommunications sockets in such cases are mounted in floor boxes and on walls. Open laying of low-voltage networks in cable channels in dwellings is usually not practiced, but can be done if the apartment owners do not mind the appearance of office design elements in their interiors. For any type of installation between cables and sockets of the electrical wiring and low-voltage cables and sockets, a distance must be maintained that complies with the standards.
To protect the equipment from the action of unbalanced network currents and atmospheric discharges, the electric lines of low-current television and video surveillance systems must be grounded. Such a requirement is contained in the American standard J-STD-607-A 2002
How much do installation services for low-voltage networks in apartment buildings cost? Let’s just say it’s fun
The communication culture of modern society is growing. And
The editors would like to thank the companies CASCADE PLUS, ECOLAN TECH, INTERNETDOM, ARCHITECTURAL ELECTRONICS for their help in preparing the material.
Source: Ideas for Your Home Magazine#85