Internal wiring. Types and types of electrical wiring

Before proceeding with the installation of electrical wiring with your own hands, you need to choose the appropriate method of cabling, determine the materials and draw up the appropriate diagram. In this article we will tell readers what types and types of electrical wiring are, as well as how to lay them in residential buildings.

General classification

So, roughly speaking, electrical wiring is divided into the following types:

• open (cable lines are mounted on the surface of walls, ceilings or other building structures);
• hidden (the power grid is laid inside these very structures);
• outdoor ( this type electrical wiring is used exclusively on the street, the wires are attached to the surface of buildings or between special supports).

In turn, each listed way gaskets have their own varieties, which we will now discuss in more detail.

open

With open electrical wiring, the following cable laying methods are used:

• in a special electrical plinth;
• in cable channels;
• in trays;
• on insulators or porcelain rollers;
• on brackets;
• in pipes (including).

Well, the most interesting thing that we would like to tell you about is what types of electrical wiring exist according to the design, starting from the input shield. Here the wiring can be divided into the following options:

These types of electrical wiring were (are) used in industrial and civil buildings. To choose the appropriate cable laying method, you need to be guided by

Internal wiring - the totality of all wires and cables with their associated fasteners and parts - is a rather complicated thing. Therefore, we will consider it in more detail.

Types of electrical wiring and methods for laying them

First you need to decide on the choice of the type of wiring. And she can be:
- open, that is, passing along the surface of walls, ceilings, and other elements of the building. The methods of laying open wiring are incredibly simple: it is either a free suspension on rollers, or its placement in electrical skirting boards and trim;
- hidden. In residential buildings, it is laid inside the structural elements of the building or its decoration. In this case, such laying methods are used as the placement of wires in the voids of building structures (for example, interfloor ceilings), as well as in grooves under plaster;
- outdoor - is placed on the outer walls of buildings or between them on supports (for example, from a residential building to a barn, workshop, bath). outdoor wiring itself can be both open and hidden.

Wires and cables

To do right choice, you need, firstly, to know the difference between a wire and a cable; and secondly, to be able to decipher the abbreviation of their marking.
So, a wire is one uninsulated or several insulated cores enclosed in a non-metallic sheath, winding or braid of fibrous materials. A cable is one or more insulated cores enclosed in a metal sheath, on top of which there is a protective cover.
The marking of wires and cables contains information about what material the conductive cores, insulation and sheath are made of, the nature of the insulation and sheath, the number of cores in the wire and cable and their cross section; and consists of alphabetic and numeric characters. The meaning of the symbols and their place in the marking is as follows:
- in the first place is the designation of the material of the conductive cores: aluminum - a, copper - the letter is omitted;
- in the second place in the marking of wires can be P - wire or PP - flat wire; in the marking of cables, the insulation material is indicated in second place: V - polyvinyl chloride, P - polyethylene, R - rubber, N - neurite;
- in the third place in the marking of the wires is the insulation material (see above), and for the cables - the sheath material (the designation of the letter symbols of the sheath material corresponds to the designation of the insulation material);
- in fourth place, in both cases, additional information is encrypted: G - flexible, H - non-combustible;
- further digital symbols indicate the number of cores and their cross section.
For example, APRN-2.5-1: A - aluminum core, P - wire, R - rubber sheath, H - non-combustible rubber sheath, 2.5 - core cross section 2.5 mm2, 1 - single-core; or cable APVG-5-3: cable - the word speaks for itself, A - aluminum core, P - polyethylene insulation, V - polyvinyl chloride insulation, G - flexible, 5 - core cross section 5 mm2, 3 - three-core.
Marks of wires and cables used in a particular place internal wiring, must be indicated on the electrification scheme of your building, which is part of the overall project.
If you still canceled the service design organizations, then the following information will not be useless to you:
- in dry rooms for open electrical wiring, you can use the following brands of wires and cables: APV, APPV, AVVG and AVRG;
- in dry rooms for hidden electrical wiring in plastered grooves - APV and APPV;
— during wet rooms(for example, showers and bathrooms) for open wiring - APPV;
- in wet rooms for hidden electrical wiring - APV and APPV;
- in hot rooms (for example, baths and saunas) for open wiring - ANRG, AVVG and AVRG;
- in hot rooms, hidden wiring is arranged only in steel pipes, which is unacceptable for living conditions;
- for external open electrical wiring, wires and cables of the AVVG, ANRG and AVRG brands are used;
- for all rooms, two-core wires with a cross-sectional size of the cores are used: copper - at least 2.5 mm2, aluminum - at least 4 mm2.
If you are observant, you have noticed that only aluminum wires and cables are listed. This is due to the fact that wires and cables with aluminum conductors are the cheapest. Copper wires and cables are 2-2.5 times more expensive, but wiring from copper wires and cables is much more reliable than an aluminum counterpart; their contact connections stronger, so the wiring does not overheat; copper wires withstand more deformations, which means that the wiring is more durable.

Consumption ecology.Usadba:How to choose The right way laying electrical wiring in the room, taking into account the features of building structures.

Features of the installation of electrical wiring directly depend on the characteristics of the building materials from which the building is built. And this is due to the fact that any building material has its own degree of fire hazard. In this article, we will consider this dependence, based on current rules electrical installations (7th edition of the Electrical Installation Code, updated on February 12, 2016) and on the practical experience of users of our portal.

Rules for the location of cable routes

The location of cable lines in the room is subject to certain rules:

• wiring in the room must be laid in accordance with strictly horizontal or strictly vertical lines, while turning the cable route is possible only by 90 ° (creating all kinds of diagonals associated with saving conductors is unacceptable);
• horizontal sections of wiring should lie at a distance of 10 ... 15 cm from the ceiling;
• vertical sections of wiring must be separated from door and window openings at a distance of at least 10 cm.

Wiring types

IN modern buildings It is customary to install two types of wiring: hidden and open. Hidden wiring is laid in the voids of building structures or inside walls (in channels made by chasing, drilling, etc.).

Wiring open type laid directly on the surface of the walls. In this case, the wires are either attached to special insulators or placed in standard cable channels.

When choosing the type of wiring when building a house, you should not be guided by your own preferences, because only SNiPs, GOSTs and PUE should be taken as the basis.

Least of all questions arise from "self-taught builders" if the wiring is mounted on walls made of non-combustible building materials. First, let's talk about such cases.

Installation of wiring on building structures made of non-combustible materials

Modern PUE rules allow the use of wires and cables exclusively with copper conductors in the premises (clause 7.1.34.).

If the room has walls and ceilings made of non-combustible materials(concrete, brick, aerated concrete blocks, ceramic blocks, gypsum slabs GWP etc.), then it is advisable to mount hidden wiring in it. Firstly, it is aesthetically pleasing, and secondly, it is safe in terms of accidental mechanical damage and, thirdly, the rules of the PUE (clause 7.1.37) fully allow the installation of hidden wiring in walls made of non-combustible materials.

In this case we are talking about living quarters. In attics, in basements (especially in unheated ones) and in technical premises, it is recommended to make open wiring.

The PUE rules state: if the building structure consists of non-combustible materials, then it is allowed to lay monolithic, non-replaceable wiring along it, using technological channels, grooves and voids for this. In this case, it is sufficient to use insulated cables or wires in a protective sheath as conductors (for example, VVG cables). In this case, the wiring is installed without the use of metal pipes, protective corrugations and other additional elements.

If the draft wall is subsequently planned to be plastered, then, as a rule, it is not necessary to resort to chasing the walls for wiring.

Of course, niches for sockets and switches will still have to be created in the wall itself. But dust, and physical work in this case will be much less than with widespread chasing of walls.

As for the power supply scheme: any self-respecting owner should have it. Indeed, in the future it will certainly be needed. The circuit is needed at least so that during the repair of the premises it does not get into the wire connected to electricity with a drill.

If you are laying wiring along walls that are not planned to be plastered in the future, then gating cannot be avoided in this case. You will also have to ditch the walls if in the process overhaul is being replaced old wiring, and remove the layer old plaster not necessary.

Is it worth it or not to create horizontal strobes? Is it possible to ditch bearing walls and concrete floors? Unambiguous answers to these questions in the environment professional builders does not exist. Of course, from the point of view of the theory of resistance of materials, man-made grooves can significantly weaken the strength of building structures (just like a thin cut of a glass cutter weakens strong glass). However, the rules of the PUE (clause 7.1.37) allow the laying of electrical networks in the grooves (in the grooves) of walls, partitions and ceilings. The main thing is not to overdo it with the depth of the strobe and with its width.

At the same time, existing technological voids (for example, in floor slabs) should be used to the maximum.

In gates, in steel sleeves, in special trays and technological channels, joint laying of wires and cables belonging to different lines is allowed (with the exception of mutually redundant conductors).

Installation of wiring on building structures made of combustible materials

A lot of questions regarding the rules for installing electrical wiring arise from people who begin to electrify premises from combustible building materials on their own. It is mainly about the frame and wooden houses. Answers to most questions can be found in the same rules of the PUE.

The design of houses made of combustible building materials allows the installation of both types of wiring (hidden and open). Which one to use depends on the preferences of the homeowner. As for the protective elements that protect the wiring from damage, and the building from fire as a result of a short circuit, their choice depends on the type of cable route.

There are two ways to lay open wiring in room:

1. Installation of retro wiring.
2. Laying wires in cable channels.

Installation of retro wiring

How the design of the retro wiring complies with the rules of the PUE is a moot point. In this regulation, the creation of this type of wiring is not even considered. However, let's try to understand this issue.

In the case of retro wiring, a special twisted cable ("retro") is mounted directly on the wall, to which it is attached using small insulators. Given that such a conductor has a coating of rayon impregnated with a non-combustible composition, it can well be attributed to the class of wires that do not spread combustion. Therefore, the installation of retro-wiring on walls made of combustible materials does not violate the rules of the PUE.

In accordance with the rules of the PUE, the distance from the conductor to the surface of the combustible material must be at least 10 mm, which is fully ensured by the design of insulators for retro wiring.

If the wire sags a lot, then the distance between the insulators can be reduced to 50 cm.

When installing retro wiring, one important nuance should be taken into account: most modern electrical appliances must be connected to a ground loop without fail. For this reason, a three-core cable should be used as part of the wiring (if one is not on sale, then it is advisable to weave it yourself).

In places where wiring passes through a wall or ceiling made of combustible materials (for example, wood), the cable (wire) must be laid in a metal pipe with localization ability. The ends of the pipe should be sealed with a non-combustible composition (for example, fire-resistant mounting foam).

The localization ability of a pipe is a quality that allows it to withstand short circuits in electrical wiring without burning out the walls of the pipe itself. In order for the pipe to have this ability, its walls must be of a certain thickness:

• for copper conductors with a cross section of up to 2.5 mm², the wall thickness is not standardized;
• for copper conductors with a cross section of 4 mm², the pipe must have a wall thickness of at least 2.8 mm;
• for copper conductors with a cross section of 6–10 mm², the pipe must have a wall thickness of at least 3.2 mm.

Open wiring in cable channels

If open type wiring is laid in cable channels and electrical skirting boards, then cables (wires) with high fire resistance (VVGng or NYM) should be used as conductors. At the same time, the material of the cable channels must also prevent the spread of fire.

Socket boxes when installed on walls made of combustible materials must have fireproof linings (for example, from asbestos cement or gypsum mortar) 10 mm thick. In places where the wiring passes through combustible structures, metal sleeves with localization ability must be installed.

Concealed wiring in combustible walls

Features of laying hidden wiring in walls made of combustible materials (for example, made of wood) boil down to the fact that wiring in the voids of such walls and partitions should run inside metal pipes with localization ability (PUE rules 7.1.38.).

There is only one rule, and in relation to its implementation, there can be no concessions. All other options (the use of plastic corrugations, metal hoses and other protective elements) should be excluded, because from the point of view of fire safety they are unacceptable.

When laying wires and cables on combustible structures (or inside them), in all cases it must be possible to replace the conductors.

By the way, the electrical wiring, spread over the floors, is the most convenient way arrangement of concealed wiring in rooms made of combustible materials. Gates to sockets and switches in this case will simply go down from the main highways.

When laying pipes and ducts for electrical wiring in technological voids of combustible structures, the ends of pipes and ducts should be covered with quickly removed non-combustible material (for example, mounting foam).

In order to ensure that when installing replaceable wiring in metal pipes it was possible to create a sufficient number of turns, in the corners of the electrical route it is necessary to use junction boxes. Access to these elements should always remain open.

The inner diameter of the pipe must be selected in such a way that the cable laid inside it occupies no more than 40% of the total free space. This rule applies to all protective elements (cable channels, corrugations, trays, etc.).

It should immediately be noted that the creation of hidden wiring in rooms with wooden walls- the process is laborious. After all, the channels for wiring will have to be equipped on your own. Space for pipes must be freed up by drilling, grooving and creating recesses.

Vertical channels in the walls should be drilled in the process of laying the log house. In this case, horizontal holes are made after the walls are ready. To make it more convenient to pull the cable through the pipes, an auxiliary cable for pulling (conductor) should be laid in advance in their inner lumen.

Cable laying under drywall, behind suspended and stretch ceilings

Hidden wiring inside frame partitions, under plasterboard or plastic sheathing, as well as behind various types ceilings is regulated by the set of building rules SP 31-110-2003 (clause 14.15) and the rules of the PUE (clause 7.1.38.). In accordance with these regulations, hidden wiring can be mounted in two ways:

1. If partitions, wall bases or their sheathing are made of combustible materials, then conductors (for example, marked VVG) must be placed in metal pipes with localization ability, or in closed boxes.
2. If building structures are made of non-combustible materials, then the wiring should consist of wires (cables) that do not spread combustion (for example, VVGng), while it should be mechanically protected by non-combustible non-metallic boxes or pipes (for example, corrugated self-extinguishing pipe).

In both cases, the wiring must be replaceable.

If the wiring is mounted under the plasterboard sheathing, and bearing profile almost closely adjacent to the wall, it is advisable to lay the wires in the strobes made in the wall or in the plaster.

When laying conductors under ceilings, under plasterboard or plastic surfaces, as well as inside frame partitions, one should be guided by the general rules for installing electrical wiring on combustible or non-combustible building structures (presented in the previous sections of the article).

Wiring under the floor

Installation of electrical wiring under the floor - perfect way create hidden cabling without resorting to horizontal wall chasing. The cable (main wire) in this case is brought directly to the locations of sockets, switches and junction boxes.

The method of creating floor wiring directly depends on what material it is planned to make the floors from. In general, it is necessary to focus on the rules of the PUE already known to us.

If the wiring is mounted in the lower layers of the cement floor, then a simple protective corrugation is sufficient for its installation. Of course, inside the screed, you can lay the cable without any corrugations, but replace the wiring without resorting to destruction. floor covering, will not work in this case. By the way, the difficulty of repairing and replacing cables (wires) is the only significant drawback of floor wiring, and it must be taken into account when determining the type of electrical wiring. published

1. Wiring

Wiring called a set of wires and cables with their associated fasteners, supporting, protective structures and parts. This definition, according to the PUE, applies to electrical wiring of power, lighting and secondary circuits with a voltage of up to 1 kV AC and DC, carried out inside buildings and structures, on external walls, territories of enterprises, institutions, microdistricts, courtyards, household plots, construction sites using isolated installation wires of all sections, as well as unarmoured power cables with rubber or plastic insulation in a metal, rubber or plastic sheath with a cross section of phase conductors up to 16 mm (with a cross section of more than 16 mm - cable lines).

Open wiring called wiring laid along the surface of walls, ceilings, trusses, supports and other building elements of buildings and structures, etc.

Open electrical wiring is also performed by current conductors, which are understood as devices consisting of uninsulated or insulated conductors and related insulators, protective sheaths, branch devices, supporting and supporting structures. Depending on the type, conductors are divided into flexible (from wires) and rigid (from rigid tires).

Concealed wiring called wiring laid inside the structural elements of buildings and structures (in walls, floors, foundations, ceilings), as well as on ceilings in floor preparation, directly under a removable floor, etc.

Outdoor wiring called electrical wiring laid along the outer walls of buildings and structures, under sheds, etc., as well as between buildings on supports (no more than four spans up to 25 m each) outside streets, roads, etc. External wiring can be open and hidden.
A tray is an open structure designed for laying wires and cables through it. The tray does not protect against external mechanical damage. Trays must be made of non-combustible materials.

2. General requirements for wiring installation

Types of wiring and ways of laying wires and cables applied depending on the characteristics environment, are determined in accordance with the requirements of the PUE. Wires and cables laid in boxes and trays must be marked.

Installation of control cables should be carried out taking into account the requirements for the installation of cable lines.

The passages of unarmoured cables, protected and unprotected wires through fireproof walls (partitions) and interfloor ceilings must be made in pipe sections, or in ducts, or in openings, and through combustible ones - in steel pipe segments.

IN industrial premises descents to switches, sockets, starters protect against mechanical damage at a height of at least 1.5 m from the floor level or service platform. In domestic premises of industrial enterprises, residential and public buildings, as well as in electrical rooms, these slopes do not protect against mechanical damage.

The smallest allowable bending radius of wires with rubber insulation is taken at least 6d, with plastic - 10d, and with a copper flexible core - 5d, where d is the outer diameter of the wire. The descent to the switches and sockets with open wiring is carried out vertically.

Crossings of openly laid unprotected and protected wires with pipelines (heating, plumbing, etc.) are performed at a distance of at least 0.05 m, and from pipelines with flammable or flammable liquids and gases - at least 0.1 m. At a distance from wires and cables to pipelines less than 0.25 m wires and cables are additionally protected from mechanical damage for a length of at least 0.25 m in each direction from the pipelines.

In parallel with heating pipelines, plumbing, etc., wires and cables are laid at a distance of at least 0.1 m, and pipelines with flammable and flammable liquids and gases - at least 0.4 m.
All connections and branches of the installation wires must be made by welding, crimping in sleeves or using clamps in junction boxes.

Open and hidden laying of installation wires is not allowed at temperatures below 15 °C.

Manual work on punching holes and furrows is mechanized with the help of devices using pneumatic, hydraulic and electrical energy, as well as devices driven by the force of the explosion of powder gases. Small-scale mechanization tools include hand-held electric drills, pneumatic hammers, perforators, hydraulic presses, construction and assembly guns, powder columns, manual and pyrotechnic mandrels, etc.

When fastening wires and devices, plastic and metal duGnmsh, duoyel with fibrous filler and spacer nut, Gyultm, studs, brackets, pins, hooks, and tshszho (Ch1 (| C | | 11.py1Y (1 dowel for construction and assembly gun and manual mandrels.

3. Laying wires in steel pipes

Laying open and hidden electrical wiring in steel pipes requires the expenditure of scarce materials and is laborious in installation. Therefore, they are used to protect wires from mechanical damage, as well as to protect the insulation and the wires themselves from destruction by caustic vapors and gases, moisture, dust and explosive mixtures from the environment entering the pipe.

Connections and connections of pipes to boxes, apparatuses and electrical receivers are performed without special sealing (when they are used to protect wires from mechanical damage), sealed (to protect pipes from dust, moisture, caustic vapors and gases) and explosion-proof to exclude the possibility of ingress inside pipes, apparatuses and electrical receivers of explosive mixtures.

Steel pipes used for electrical wiring are divided into three groups: ordinary water and gas pipes, light and thin-walled electric welded pipes.
Before installation inner surface pipes are cleaned of scale and burr and the inner and outer surfaces are painted with asphalt varnish.

Pipes laid in concrete are not painted on the outside for better adhesion to concrete. Galvanized pipes are laid without painting. During installation, they adhere to the normalized values ​​\u200b\u200bof the angles and bending radii of pipes, depending on the diameter of the pipes, the number and cross section of the wires laid in them.

Ordinary water and gas pipes are used only in explosive installations; light - in justified (from the point of view of metal savings) cases with open laying in dry and damp rooms; as well as for hidden laying in dry and damp rooms, in attics, in underfloor floors, foundations and other building elements with sealing of the entry points into the boxes and connection of pipes with steel couplings on the thread. Thin-walled electric-welded pipes are used for open laying in dry and damp rooms without sealing the joints and entering the boxes.

Electrical installation organizations use the industrial method of installing steel pipes. Procurement of pipes, their processing, cleaning, painting, picking into separate units and packages is carried out in the MEZ. At the installation site, the pipes are laid in ready-made units, connected to each other and wires are pulled into them.

Procurement of pipe blocks in the MEZ provides for the use of normalized elements in the form of corners with standard bending radii. Pipes are prepared in workshops either according to sketches or models that imitate the location of electrical receivers, to which pipes with wires are connected.

Rice. 1. Connections and inlets of steel pipes into boxes (b):
1 - threaded coupling; 2, 9 - sleeve on screws; 3 - segment
pipes with welding on the edges; 4, 7 - sleeve for welding;
5 - coupling with a socket; 6 - on the thread in the branch pipe of the box;
8 - installation grounding nuts on both sides

Methods for connecting steel pipes are shown in fig. 1. Connection with a threaded coupling is performed with sealing with tow on minium or a special fluoroplastic tape of the FUM brand. Such a connection is mandatory for ordinary and light water and gas pipes in explosive areas, damp, hot rooms, as well as in rooms containing vapors and gases that have harmful effect for wire insulation. In dry, dust-free rooms, it is permissible to connect steel pipes with sleeves or cuffs, without sealing (see Fig. 1, a).

Steel pipes with open laying, they are fastened with brackets and clamps. It is forbidden to fasten steel pipes of all types to metal structures using electrical and gas welding. When laying steel pipes, certain distances between their attachment points must be maintained: no more than 2.5 m for pipes with conditional pass 15-20 mm, 3 m - with a passage of 25-32 mm, no more than 4 m - with a passage of 40-80 mm, no more than 6 m - with a passage of 100 mm. Permissible distances between broaching boxes depend on the number of bends in the pipe line: with one - no more than 50 m; with two - no more than 40 m; with three - no more than 20 m. The choice of the diameter of the steel pipe for placing wires in it depends on their number and diameter of the wires.

To avoid damage to the wire insulation during pulling, plastic bushings are installed at the ends of the steel pipes. To facilitate the pulling of wires, talc is blown into the pipes and a steel wire with a diameter of 1.5-3.5 mm is preliminarily tightened, to the end of which a taffeta tape with a ball is attached. Then into the pipe with compressed air of a small mobile compressor at an overpressure of 200-250 kPa, a ball is blown in, with the help of a taffeta tape, a wire is drawn in and behind it a wire or cable attached to the wire.

In vertically laid pipes, it is recommended to tighten the wires from the bottom up. Connections and branches of wires laid in pipes are made in boxes and boxes.

4. Laying wires on cables and strings

Rope wiring. A cable as a supporting element of electrical wiring is a steel wire or rope stretched in the air, designed to suspend wires, cables or their bundles to them.

For laying indoor networks for industrial electrical installations with voltage up to 660 V, APT installation wires are used, which have aluminum conductors, rubber insulation and a carrying cable. The insulated wire cores are twisted around an insulated galvanized cable (wires with a cross section from 2.5 to 35 mm2, two-, three- and four-wire). The wire cores have a distinctive marking in the form of stripes on the surface of the insulation.

For external wiring, AVT brand wire with aluminum conductors, thickened PVC insulation and a carrying cable is used; in agriculture - AVTS wires with aluminum conductors, PVC insulation and a carrying cable. For cable wiring, installation wires are also used. APR (PR), APV (PV) and unarmoured protected cables of brands AVRG (VRG), ANRG (NRG), AVVG (VVG), which are attached to a special carrier cable.
Installation of electrical wiring performed in two stages.

At the first stage, the workshop prepares and assembles electrical wiring elements, complete anchor, tension structures and supporting devices and transport them to the installation site.

At the second stage of installation, cable wiring is mounted on pre-installed tensioners and pendants indoors.
When preparing cable wiring in the workshop, branch, junction and inlet boxes, grounding jumpers, tension couplings are installed and fixed on it. Luminaires are attached to the wiring, as a rule, at the second stage of installation, when the cable wiring is unwound on the floor, temporarily suspended at a height of 1.2-1.6 m for straightening wires, suspension and connection of luminaires (if they were not mounted on a cable line in workshops). Then the electrical wiring is lifted to the design site, the cable is fixed at one end to the anchor structure, connected to intermediate hangers and ties, pre-tensioned (manually for spans up to 15 m and with a winch for large spans) and put on the second anchor hook. After that, the final tension and grounding of the carrier cable and all metal parts of the line, the adjustment of the sag, and the connection of the line to the supply line are carried out (Fig. 2).

Rice. 2. Scheme of assembly and suspension of cable wiring at the installation site:
1 - temporary and permanent anchors; 2 - tension clutch; 3 - end loops; 4 - special winch or chain hoist;
5 - free end of the carrier cable; 6 - auxiliary cable segment; 7 - wedge clamp; 8 - lash of cable wiring; 9 - inventory stands; 10 - dynamometer; 11 - vertical wire suspension

A manual winch is used to tension the cable. The cable tension is controlled by a dynamometer.

The sag during adjustment is taken equal to: 100-150 mm for a span of 6 m; 200-250 mm for a span of 12 m. The carrying cables are grounded at two points at the ends of the line. On lines with a neutral wire, grounding is carried out by connecting the carrier cable to the wire with a flexible copper jumper with a cross section of 2.5 mm, and on lines with isolated neutral, by connecting the cable to the bus connected to the ground loop. The carrier cable is not used as a grounding conductor.

String wiring. string wiring used for fastening cables of SRG, ASRG, VRG, AVRG, VVG, AVVG, NRG, ANRG brands, STPRF and PRGT wires on hard grounds. Such wiring is performed on a stretched steel wire (string) or tape fixed close to the building foundations (ceilings, trusses, beams, walls, columns, etc.). All elements of string electrical wiring are reliably grounded.

5. Installation of busbars with voltage up to 1 kV

Busbars are divided into: main three-phase alternating current (ser. ShMA) for rated currents of 1600, 2500 and 4000 A; main direct current (ser. ShMAD) for rated currents 1600, 2500, 4000 and 6300 A; distribution (ser. ShRA) for rated currents of 250, 400 and 630 A (their kit includes straight, angled and tee sections, input and branch boxes with automatic switches or circuit breakers with fuses for connecting electrical receivers for voltage 380/220 V); trolley (ser. ШТМ) for nominal points of 200 and 400 A (for power trolleys for overhead cranes, electric hoists and power tools); lighting (ser. ShOS) for rated currents of 25, 63 and 100 A (for lighting networks in rooms with a normal environment).

The section of the SCO series is a box, inside which four insulated copper conductors with a cross section of 6 mm2 are laid. Every 0.5 m, places are provided for plug-in connection of single-phase power receivers according to the phase-zero scheme. To connect the sections to each other, four-pole plug-in end connections are provided.
With the current state of organization and installation technology, busbar sections in workshops are assembled into enlarged blocks, which are then mounted in the workshops of enterprises under construction.

Busbar installation on construction site comes down to their assembly and installation. Bus ducts are mounted on trusses, columns, walls using brackets or suspensions, as well as on the floor on special racks (mainly closed distribution bus ducts). Sections of busbars are pre-assembled into blocks of three and four sections, and then installed on supporting structures.

6. Wiring in hazardous areas

In hazardous areas of all classes, cables with PVC, rubber and paper insulation in PVC, rubber and lead sheaths and wires with PVC and rubber insulation in water and gas pipes are used. The use of cables and wires with polyethylene insulation and cables in a polyethylene sheath in explosive zones of all classes is prohibited.

In explosive zones of classes B-1 and B-1a, cables and wires with copper conductors are used only; in zones of classes V-16, V-1g, V-1a and V-11 - cables and wires with aluminum conductors and cables in an aluminum sheath. In explosive zones of all classes, uninsulated (bare) conductors, including down conductors to cranes, electric hoists, etc., are not used.

Methods for laying wires and cables choose based on recommendations. PUE. In power networks with voltages up to 1 kV, a special fourth core of a cable or wire is used for grounding or grounding.

In zones of classes B-1, B-1a, B-11 and B-11a, the passages of openly laid single cables through walls and ceilings are made through pipe sections embedded in them, the end of which is sealed with a pipe gland. When cables pass into an adjacent explosive room, pipe glands are installed from the side of the explosive room more than high class, and for the same classes of rooms - from the side of the room containing explosive mixtures of a higher category and group. In class B-1 rooms, pipe seals are installed on both sides of the passage. When cables pass through ceilings, pipe sections are released from the floor by 0.15-0.2 m. Cable passages through walls in explosive rooms are performed in accordance with fig. 3.

If necessary protect wires and cables from mechanical or chemical influences they are enclosed in steel water and gas pipes. For connections, branches and pulling wires and cables in steel pipes, cast iron explosion-proof boxes of series B (fittings) are used (Fig. 4).

In damp rooms, pipelines are laid with a slope towards junction and pull boxes, and in especially damp rooms and outside - towards special catchment pipes. In dry and humid rooms, the slope towards the boxes is done only where condensation can form.

Rice. Fig. 3. Cable passages through the internal walls of rooms with US-65 sealing compound (a) and gland seal (b):
1 - ground bolt; 2 - pipe section; 3 - cable;
4 - seals made of cable jute or asbestos cord;
5 - sealing compound US-65; 6 - cement mortar;
7 - stuffing box (L is the length of the stuffing box); 8 - rubber sealing
ring; 9 - washer

Rice. 4. Explosion-proof cast-iron boxes: o - straight through passage (checkpoint); b - passage through the bottom (efficiency);
c - tee branch (CTO); g - tee with
branch to the bottom (KTD); d - cross branch (KKO);
e - passage dividing (KPR); g - checkpoint
separating for local tests (KPL)

The pipes are connected to each other, as well as to fittings, boxes, boxes, inlet fittings of machines, casings of apparatuses and lamps, on a thread with a winding of hemp yarn impregnated with drying oil or paints rubbed in oil (red lead, whitewash), or FUM tapes (fluoride sealant - ny material) with a width of 10-15 mm. For sealing threaded connections it is forbidden to use PVC tape and other insulating materials. Connection and fastening of pipes by welding is also not allowed.

To prevent the transfer of an explosive mixture from one room to another or outside, on pipelines in explosive rooms, separating sealing boxes KPP or KPL are installed, providing for the possibility of local tests, filling them with sealing putties and mastics.

Such seals are installed at the points of transition of pipelines from explosive premises of higher classes to explosive premises of lower classes (for example, from a class B-1 room to a class B-1a room. US-65 composition is used as a sealant.

In hazardous areas of any class, electrical installations of all AC and DC voltages are grounded (zeroed). As zero protective (grounding) use only conductors specially designed for this. Additionally, it is allowed to use building structures, steel pipes for electrical wiring, metal sheaths and cable armor for this purpose. Steel pipes are grounded at both ends. Pipes that do not have connections can be grounded in one place.

The device of connecting and branch couplings on cables in explosive installations is prohibited.

7. Testing of internal electrical networks

At the end wiring installation(and busbars), before their acceptance into operation, control tests are carried out.

1. Insulation resistance test power wiring(busbars) is carried out with a 1 kV megger. The insulation resistance must be at least 0.5 MΩ.

The insulation resistance is measured with the fuses removed between adjacent fuses (or behind the last fuses between any wire and earth) and between two wires. When measuring insulation resistance, electrical receivers, as well as devices, devices, etc., must be turned off. When measuring insulation resistance lighting network lamps must be unscrewed, and socket outlets, switches and group boards are connected. Busbar insulation resistances are measured between each busbar and protective cover, as well as between every two tires.

2. Insulation test overvoltage 1 kV industrial frequency for 1 min. This test may be replaced by a 1 min measurement of the insulation resistance with a 2.5 kV megger. At the same time, if the value of the insulation resistance is less than 0.5 MΩ, a test with a voltage of 1 kV of industrial frequency is mandatory.

We figured out the sockets and switches, we turn to the essence of things

Electrical wiring refers to all electrical wires and cables laid in a house or apartment. They are designed to supply electricity to household and lighting appliances. Today we are nowhere without technology, so let's take a closer look at all these cables and junction boxes.

Types of electrical wiring

There are two types of electrical wiring: hidden and open. The structure of the wiring itself, regardless of its type, is always the same: the main power cable is inserted into the apartment or house, which is connected to electric meter. Feeding branch cables run from the meter to all rooms. In rooms, cables branch out even more: to sockets, to switches, to lighting fixtures.

1. Hidden wiring

2. Open wiring

Wire types

The wire

1. PVC wire

This wire is often used to repair electrical networks. It is also suitable for making extension cords and cords for any kind of technique. Flexibility and lightness make PVA an indispensable tool for lighting and mounting sockets.

2. PBPP wire

Flat electrical wire with two or three solid copper conductors. It is a universal conductor electric current, high quality: PBPP can be used when carrying out electrical work in a private house, apartment or country house. It is suitable for connecting lighting as well as mounting electrical sockets and switches.

Cable

1. CableNYM

High-quality German cable, consisting of 1-5 cores. Used for laying lighting and power networks both indoors and outdoors. His distinguishing feature– high degree of security. This cable is also moisture and heat resistant, but does not like sunlight, so it must be protected from direct rays.

2. VVG cable

Cable with excellent insulating characteristics. It consists of a single core, making it convenient to lay inside the walls. Most often, VVG is used when they are independently involved in the installation or replacement of electrical wiring in an apartment. The service life of such a cable is at least 30 years.

Wiring for powerful equipment

Distribution boxes