The main points in the design of electrical wiring in the building. Requirements of the PUE and other regulatory documents for electrical wiring in civil buildings. The composition of the project documentation
Electrical wiring in residential premises must comply with the standards in force in the Russian Federation. Knowing the rules for installing electrical wiring, you can do this work without violating electrical safety requirements, thereby protecting your life and protecting household appliances from breakage. There are three types of electrical wiring:
- open;
- closed;
- combined.
All three types are subject to general requirements that must be taken into account when developing a wiring plan.
These requirements apply to the placement of wiring elements: meters, junction boxes, sockets, switches and placement of electrical wires.
- Junction boxes, switches and sockets, electricity meters are placed in places accessible for their maintenance (while all current-carrying parts are closed).
- It is advisable to place switches in each room on one side of the door. Placement height - 1.5 meters from the level of the finished floor (floor covering). Please note: when opening the door to the room, the switch must remain within reach.
- Sockets are mounted at a height of 0.5 - 0.8 m from the level of the finished floor. Their locations are determined by the planned arrangement of electrical equipment.
- There are also requirements for the number of sockets in an apartment: according to fire safety rules, they are installed at least one per six square meters. In the kitchen, regardless of its area, at least three must be installed.
- In wet rooms - toilets and bathrooms - it is forbidden to install sockets. But there is one caveat: to connect hair dryers and electric shavers, it is allowed to install sockets in bathrooms that are powered by double-insulated isolating transformers.
- It is not allowed to install sockets closer than half a meter from grounded radiators, gas stoves, steel pipelines and other metal devices.
- It is advisable to install sockets on the interior partition at one point on each side of the partition. In this case, they are connected in parallel through a through hole in the wall.
- All branches and connections of electrical wires in the apartment are carried out only in branch and junction boxes.
So that in the future during repairs there are no problems with damage to the wiring, the wires should be laid only horizontally and vertically. Moreover, it is necessary to store the network laying plan. There are generally accepted rules for placing wires:
- horizontal sections are placed at a distance of 50 - 100 mm from beams and cornices and 150 mm from the ceiling and plinth (in the latter case, a distance of 200 mm is allowed);
- vertically located sections of the electrical network must be at least 100 mm away from the corners of the room and door and window openings. At the same time, the contact of the wire with the metal structures of the building (if any) is not allowed;
- if heating or hot water pipes are located near the wiring, it must be protected with asbestos gaskets. Another acceptable option is to use a wire with a thermal protective coating;
- if the wire is placed parallel to a gas pipe (or a pipeline with any other combustible substance), the distance between them must be at least 0.4 meters;
- it is forbidden to lay electrical wires in bundles in the apartment. It is also unacceptable to place them with a gap of less than 3 mm.
Scheme of correct electrical wiring in the house
The cores of the grounding and grounding wires are interconnected by welding. Electrical appliances to be protected are connected to the protective conductors by means of bolted connections.
To zero stationary electric stoves, a separate conductor is laid from the apartment meter. Its cross section must be equal to the cross section of the phase wire. This conductor is connected in front of the electric meter to the protective conductor of the power supply network. Grounding and neutral conductors should not have switches or fuses. This rule must be observed, otherwise, at the time of protection operation, all household appliances will be in the zone of influence of the dangerous potential of the network.
All of the above requirements relate to the field of electrical safety.
Installation requirements depending on the type of gasket
Proper installation involves not only compliance with general rules: special requirements have been developed for each type of electrical installation in an apartment.
Types of electrical wiring
open laying
The easiest way is an open gasket. It looks, of course, not quite beautiful, but it is not necessary to ditch the walls under the wires. It is difficult to imagine such a method in an apartment, but in the back rooms of country houses such a picture is not uncommon. But even for such a primitive laying method, there are requirements:
- To perform electrical wiring in an open way, flat wires APRV, APR or APPV are used. If the walls of the room are combustible (for example, made of wood), asbestos sheets with a thickness of at least 3 mm are laid between the wires and the base. The distance from the wire to the edge of the sheet is over 5 mm. The asbestos gasket is fixed to the wall with nails in increments of 200 to 250 mm in a checkerboard pattern. For several groups of wires, it is allowed to use one common asbestos gasket (the distance between adjacent wires must be 5 mm or more).
- The wire is attached to the wall with a tin strip through a cardboard gasket. And for this purpose, a special cardboard-electrical insulator is used. The width and length of the gasket should exceed the similar dimensions of the tin bracket by several millimeters. The wire must be tightly wrapped around the fastener.
- Inside the junction box, the insulated ends of the wires must not be allowed to touch.
- Before entering the box, the wires are attached to the wall. The distance from the box body to the fastening element is 50 mm.
- Sockets and switches when wiring in an open way are mounted on special sockets: plastic or wooden. Their diameter exceeds the similar size of sockets by 8 - 10 millimeters.
closed type
The safest way to lay the internal electrical network is closed. The wires in this case are inside non-combustible material. They are inaccessible to accidental mechanical damage, do not oxidize and do not threaten the apartment with fire.
Concealed electrical wiring in the apartment
- If the walls of the house are built of wood, then closed wiring, like open wiring, is carried out on asbestos sheets. These requirements do not apply if the house is built of brick or reinforced concrete.
- Crossing flat wires is not allowed. If this is unavoidable, the intersection should be reinforced with insulating tape (3 - 4 layers per wire).
- In the strobes, the wires are fixed with alabaster. Often use special plastic clamps. With closed wiring, it is not permissible to use nails as fasteners.
- Branches and wire connections are carried out by welding, crimping or soldering. These operations can be performed using special clamps in the space of branch boxes.
- If the walls in the apartment are sheathed with drywall, the electrical wiring is perfectly placed under its layer and does not require grooves in the base. Several holes of a rather large diameter are drilled in drywall sheets - from 30 to 40 mm in the direction of the wiring route. Through these holes, you can push a wire loop, with which the wires are pulled in the right direction. However, this is only true when the wiring is replaced in an already finished room. If the drywall has not yet been installed, it is easier to first carry out the wiring of the electrical network, and then sheathe the walls.
Combined method
The laying of electrical wires of the internal network in the apartment can also be carried out in a combined way using cable channels. This method is a cross between open and closed types of wiring. The cable duct can be made of non-combustible plastic, aluminum alloy or galvanized steel. It is mounted easily, but in this case there are some requirements, violating which, you can doom yourself to endless alterations:
- The first step is to choose the right box type. On sale there are several options for the execution of cable channels. These are wall models, floor plinths, ceiling-type modifications, etc. The most common (and most practical) option is a wall-mounted cable channel made of plastic.
Rules for the placement of cable channels
- The size of the cable channel should provide free placement of the required set of wires.
- If it is supposed to place power and low-current wires in one cable channel, it is better to choose a sectional design. Keep in mind that the lines should not twist or cross each other. Otherwise, interference will be observed in the low-current line during signal transmission.
- Since the combined laying scheme is located in the visibility zone, it is not subject to the requirements of the horizontal and vertical alignment of the route. You can also lay the cable channel diagonally. However, most users prefer to mark the route of the power grid in their apartment according to the law of closed laying.
Cable channels in a clapboarded room
- Inexperienced home craftsmen are advised to purchase boxes with a margin of 10 to 15% of the required total network length. Do not rush to immediately cut the materials into segments of the required length: very often the scheme developed on paper in fact requires some adjustment.
- Do not take the direction of the corners or contours of openings in the apartment as a base: it is necessary to control the horizontal and vertical position of the cable channel using a plumb line (construction) or level.
In contact with
The presence of branched and extended power and lighting networks, as well as a wide variety of architectural, planning and technological solutions, depending on the purpose of buildings and premises, causes great difficulties in creating unified electrical wiring.
At the same time, during the construction of a number of buildings for various purposes (schools, children's institutions, clinics, hotels, educational buildings of vocational schools, etc.), large-panel floor structures of full factory readiness, including floors, will be used in the future. In these buildings, the possibility of laying electrical networks in the preparation of the floor, given or overlying floors, which is currently widely used, is practically excluded.
In this regard, design and engineering work is underway to create a system of metal and plastic ducts in the proper aesthetic design, intended for laying all types of electrical networks. In addition, some buildings use the SCO bus duct and the KL-type duct designed for industrial buildings, in which the wires of lighting networks are laid. For the same purposes, a single-phase busbar duct designed by Glavelectromontazh will be used. In some cases, distribution industrial busbars of the ShRA type are used for laying supply lines. It should be noted that the use of boxes (especially with plug connections) increases the industrialization of installation work and greatly simplifies the change of wiring and fixtures. Thus, a gradual transition from hidden to open wiring is planned.
Let us dwell on some of the most common types of electrical wiring used in public buildings.
Supply lines should, as a rule, be made replaceable: a) openly - in vinyl plastic pipes, boxes made of fireproof materials, as well as unarmored cables. Open laying on trays in technical undergrounds, floors, basements can be used, provided that pipelines with combustible gases and liquids are not laid in these rooms and only qualified personnel have access to these rooms. In this case, the height of the PUE trays is not regulated. In rooms without increased danger, where unauthorized persons can have access (with a mains voltage above 42 V), the trays should be located at a height of at least 2 m, and in rooms with increased danger and especially dangerous - at least 2.5 m;
b) hidden - in the channels of building structures without pipes, in plastic pipes and boxes. In some buildings, special shafts with floor ceilings are arranged, in which floor distribution points and group shields are installed and vertical sections of supply lines are laid. To enter the mines on the floors there are lockable doors.
It should be borne in mind that plastic pipes, both for open and hidden wiring, can be used with some restrictions, which must be taken into account when designing.
In order to save steel pipes, the norms allow their use only in cases where the use of plastic pipes is prohibited, as well as in some cases specified in SNiP.
Group networks of electric lighting should, as a rule, be carried out hidden and replaceable in the channels and voids of building structures, and in the absence of such a possibility - in plastic pipes. Lighting wiring in small public buildings can be carried out with hidden special wires that cannot be replaced, for example, APPVS, directly on fireproof bases, in furrows, seams in building structures, under plaster, etc.
In technical undergrounds, basements, attics, in pumping and heating points, as well as in wooden buildings, wiring can be carried out openly in compliance with the requirements
In rooms without increased danger, lighting networks are also laid in plastic and metal boxes, in plastic electrical skirting boards, and also hidden in collapsible partitions that have recently become widespread in metal hoses or other pipes.
In public buildings, suspended ceilings are often used, behind which sanitary and electrical communications are laid. In these ceilings, as a rule, luminaires of special designs are built in. Wiring in the cavities above impassable suspended ceilings perform:
with suspended ceilings made of combustible materials - in steel pipes;
with suspended ceilings made of fireproof and slow-burning materials - in vinyl plastic pipes, metal hoses or without pipes, but protected by wires and cables. Wiring in cavities above ceilings is considered hidden.
Switches for general lighting are installed at a height of 1.5 m from the floor, and in rooms for children - 1.8 m.
Switches for fire hazardous and explosive premises, damp and damp, it is advisable to take out of these premises. The same applies to pantries, warehouses and other premises with material values.
The installation of socket outlets in the lighting network is determined by the interior of the room and ease of use, but should not exceed 1 m from the floor. In schools and children's institutions in the premises for the stay of children, sockets are installed at a height of 1.8 m from the floor. In bathrooms, shower rooms and pre-shower sockets, sockets should not be installed, with the exception of bathrooms, provided that the sockets are connected through a separating transformer.
Power distribution networks can be laid, depending on the purpose of the premises, hidden or open, in the same ways that are indicated for lighting networks. When installing technological equipment in the middle of the room, the power supply to these electrical receivers can be carried out in plastic pipes, and at the exit from the floor - in sleeves made of steel pipes.
1 Open laying of vinyl pipes in buildings with a height of 10 floors or more is prohibited.
2 Laying on trays of unprotected insulated wires in technical undergrounds is allowed if there are no gas pipelines in them, relative humidity is not more than 65% and in cases where only trained personnel have access to undergrounds. The height of the wire laying in this case is not standardized.
GOST R 50571.15-97
ELECTRICAL WIRING
Electrical installations of buildings. Part 5
Selection and erection of electrical equipment.
chapter 52.
Wiring systems
OKS 27.020; 29.020
OKSTU 3402
Introduction date 1997-07-01
Foreword
1 DEVELOPED by Elektromontazh JSC
2 INTRODUCED by the Technical Committee for Standardization TK 337 "Electrical equipment of residential and public buildings"
3 APPROVED AND INTRODUCED BY Decree of the State Standard of Russia dated April 8, 1997 No. 125
4 This standard contains the complete authentic text of the international standard IEC 364-5-52 (1993) “Electrical installations of buildings. Part 5. Selection and installation of electrical equipment. Chapter 52. Wiring" with the exception of those in italics in paragraphs 522.1.1, 522.6.2, 522.7.1, 522.12.2. .Replaced in these clauses, the authentic text of IEC 364-5-52-93 is given in annex A to this standard.
The standard also contains additional requirements highlighted in italics in paragraphs 521.1 (note and text in table 52 R), 521.3 (for schemes 11, 11A, 12-17, 21, 31, 31A, 32, 32A, 51, 52, in table 52H ), 522 (note 2), 525, 526.2, 527.1.1, 527.1.5, 527.2.4, 528.1.1
5 INTRODUCED FOR THE FIRST TIME
Introduction
This standard is part of a set of state standards for electrical installations of buildings, developed on the basis of the international standard IEC 364 "Electrical installations of buildings".
The numbering system of sections and clauses in this standard corresponds to that established in IEC 364-5-52-93, therefore, in this standard, in the designation, for example, clause 521.1, the number 5 indicates the part number of the international standard IEC 364-5-52-93, the numbers 52 - chapter number, 521 is the section number of the standard.
The use of the numbering system established by the IEC ensures the interconnection of the requirements of private standards of the complex of state standards for electrical installations of buildings (GOST R 50571).
The requirements of this standard should be taken into account when developing and revising standards, norms and rules for the device, testing, certification and operation of electrical installations of buildings.
The requirements regulated by the standard are determined by the type of wire or cable used, the method of their installation, laying, external influencing factors, conditions for limiting the spread of combustion, proximity to other engineering networks and structures, as well as the conditions for providing maintenance.
The scope of the standard is in accordance with GOST 50571.1 (part 1, section 1).
Due to the significant differences in the requirements for external influencing factors (WWF) adopted in Russia and the CIS from the requirements of the IEC and ISO standards, this standard additionally, and in a number of paragraphs and instead of the requirements of IEC 364-5-52-93, includes the requirements of domestic and interstate (CIS countries) standards.
All additions and changes made to the text of the standard are in italics, and the corresponding authentic text is given in Appendix A to this standard. Appendix B contains the main provisions for checking the resistance of the installed electrical wiring to the effects of special environments.
The standard contains a number of requirements and provisions that differ significantly from the requirements of the current Electrical Installation Rules (PUE). The most important of them are:
1 Insulated wires are allowed to be laid only in pipes, ducts and on insulators. It is not allowed to lay insulated wires hidden under plaster, in concrete, in brickwork, in the voids of building structures, as well as openly on the surface of walls and ceilings, on trays, on cables, and other structures. In this case, sheathed insulated wires or cables must be used.
2 In single- or three-phase networks, the cross section of the zero working conductor and the PEN conductor must be equal to the cross section of the phase conductor with a cross section of 16 mm or less for conductors with a copper core and 25 mm or less for conductors with an aluminum core. For large sections of phase conductors, a reduction in the section of the zero working conductor is allowed, provided that:
- the expected maximum operating current in the neutral conductor does not exceed its long-term permissible current;
- zero protective conductor has overcurrent protection.
3 It is not recommended to use soldering when connecting conductors of power circuits.
4 Increased requirements for sealing the passage of electrical wiring through walls and floors.
The introduced requirements increase the operational reliability, electrical and fire safety of electrical installations in buildings.
Until the PUE is brought into line with the IEC set of standards for electrical installations of buildings, the PUE is applied in terms of the requirements that do not contradict the specified set of standards.
1 AREA OF USE
This standard specifies requirements for the selection, installation and operation of electrical wiring.
The standard applies to electrical installations of power, lighting and secondary circuits with voltages up to 1000 V AC and 1200 V DC, performed inside buildings and structures, as well as on their outer walls and in their immediate vicinity using insulated wires and cables (GOST R 50571.1) .
Measure cable insulation resistance CORRECTLY. Measurement of electrical insulation resistance RISO up to 40 TΩ; Choice of measuring voltage in the range from 50 V to 10 kV; Automatic discharge of the capacitance of the object under study after the completion of the measurement of the electrical insulation resistance; Automatic calculation of absorption and polarization coefficients (degree of wetting and insulation aging) AB1, AB2, DAR, PI; Measuring current - 1.2 mA, 3 mA or 5 mA; Two- and three-wire method for measuring electrical insulation resistance using conductors up to 20 m long; Support for AutoISO-5000 adapter with voltage up to 5 kV; Capacitance measurement in the process of measuring electrical insulation resistance; Measurement of electrical insulation resistance by increasing step voltage (SV); Measurement of dielectric discharge coefficient (DD); Localization of damage (burning). |
2 REGULATORY REFERENCES
This standard uses references to the following standards:
GOST 9.005-72 ESZKS. Metals, alloys, metallic and non-metallic inorganic coatings. Permissible and impermissible contacts with metals and non-metals
GOST 9.303-84 ESZKS. Metallic and non-metallic inorganic coatings. General selection requirements
GOST 12.1.004-91 SSBT. Fire safety. General requirements
GOST 12.1.010-76 SSBT. Explosion safety. General requirements
GOST 12.2.007.0-75 SSBT. Electrical products. General safety requirements
GOST 12176-89 Cables, wires and cords. Flame Propagation Test Methods
GOST 14254-96 Degrees of protection provided by enclosures (IP code)
GOST 15150-69 Machinery, instruments and other technical products. Versions for different climatic regions. Categories, conditions of operation, storage and transportation in terms of the impact of environmental climatic factors
GOST 15543.1-89 Electrical products. General requirements in terms of resistance to climatic external Inactive factors
GOST 15963-79 Electrical products for areas with a tropical climate. General technical requirements and test methods
GOST 17516.1-90 Electrical products. General requirements in terms of resistance to mechanical external influences
GOST 24682-81 Electrical products. General technical requirements regarding the impact of special environments
GOST 24683-81 Electrical products. Methods for monitoring resistance to special media
GOST 28668.1-91 Low-voltage distribution and control devices. Part 2. Particular requirements for busbar systems (busbars)
GOST R 50462-92 Identification of conductors by colors or numbers
GOST R 50571.1-93 Electrical installations of buildings. Key points
GOST R 50571.2-94 Electrical installations of buildings. Part 3. Key Features
GOST R 50571.8-94 Electrical installations of buildings. Part 4. Security requirements. General requirements for the application of protective measures to ensure safety. Requirements for the application of protective measures against electric shock
GOST R IEC 449-96 Electrical installations of buildings. Voltage ranges
52 GENERAL
52.1 When selecting and installing electrical wiring, the requirements of GOST R 50571.1 for cables and wires for their termination and / or connection, for their support or suspension structures, protective shells and methods of protection against external influences must be taken into account, as well as general safety requirements in accordance with GOST 50571.1 ( part 2).
Note - The requirements of this standard, in general, also apply to protective conductors, while in the relevant private standards of the GOST 50571 set of standards, additional requirements are established for protective conductors.
521 Types of wiring
521.1 The method of installation of electrical wiring, depending on the type of wire or cable used, must be selected in accordance with table 52F, provided that the external influences on the wires or cables comply with the requirements of the current standards for these wires and cables.
521.2 The method of installation of electrical wiring, depending on the place of laying, must comply with table 52G.
521.3 Examples of electrical wiring are given in table 52H.
NOTE Other types of wiring not covered by this standard may only be used if they meet the general requirements of this standard.
521.4 Busways
Bus ducts must meet the requirements of GOST 28668.1 and be mounted according to the manufacturer's instructions. At the same time, installation work is carried out in strict accordance with the requirements of sections 522 (except for clauses 522.1.1, 522.3.3, 522.8.1.6, 522.8.1.7 and 522.8.1.8), 525-528.
521.5 AC circuits Conductors enclosed in ferromagnetic sheaths shall be laid in such a way that all the conductors of each circuit are in the same sheath.
NOTE If this condition is not met, overheating of the wires and significant voltage losses due to the effect of inductance may occur.
Table 52F - Wiring Selection
| Wires and cables | Mounting method | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| without attachment | in pipes | in boxes | in special boxes | on patches and brackets | on insulators | on a cable (string) | |||
| bare wires | - | - | - | - | - | - | - | - | |
| Insulated wires | - | - | + | + | + | - | + | - | |
| Insulated wires in a protective sheath and cables in sheaths (including armored and mine- | stranded | + | + | + | + | + | + | 0 | + |
| ral insulation) | Single core | 0 | + | + | + | + | + | 0 | + |
Designations:
"+" - allowed;
"-" - not allowed;
Note - Special box - a box of rectangular section, designed for laying wires and cables, which does not have removable or opening covers.
Table 52G- Installation of electrical wiring systems
| Place of laying | Mounting method | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| without attachment | with direct attachment | in pipes | in boxes | in special boxes | on patches and brackets | on insulators | on a cable (string) | ||
| In the voids of building structures | 21, 25, 73, 74 | 0 | 22, 73, 74 | - | 23 | 12-16 | - | - | |
| in cable channels | 43 | 43 | 41, 42 | 31, 32 | 4, 23 | 12-16 | - | - | |
| in the ground | 62, 63 | 0 | 61 | - | 61 | 0 | - | - | |
| In building structures | 52, 53 | 51 | 1, 2, 5 | 33 | 24 | 0 | - | - | |
| Open laying on building structures | - | 11 | 3 | 31, 32, 71, 72 | 4 | 12-16 | 18 | - | |
| In the air | - | - | 0 | 34 | - | 12-16 | 18 | 17 | |
| In water | 81 | 81 | 0 | - | 0 | 0 | - | - | |
Designations: "+" - allowed;
Designations:
"+" - allowed;
"-" - not allowed;
"0" - not used or usually not used in practice.
Notes
1 digits in the table indicate the reference number (see table 52H)
Table 52G - Installation of electrical wiring systems
2 Permissible current loads according to GOST R 50571 (IEC 364-5-523).
Table 52H - Installation examples
NOTE The illustrations do not give a precise description of the products or installation practices, but of the method of installation.
| Example | Description | Reference number |
|---|---|---|
| Insulated wires in pipes embedded in walls | 1 | |
| Multi-core cables in pipes embedded in walls | 2 | |
| 3 | ||
 |
3A | |
 |
4 | |
| - | Single or multi-core cables in special ducts on the walls | 4A |
| 5 | ||
| 5A | ||
| - | Sheathed insulated wires, sheathed cables and/or armored cables, solid or stranded: | |
| 11 | ||
 |
11A | |
| 12 | ||
| 13 | ||
| - on brackets fixed horizontally or vertically | 14 | |
| 15 | ||
| 16 | ||
 |
Insulated wires in a protective sheath, single or multi-core sheathed cables suspended on a cable (string) or having a carrying cable (string) | 17 |
| 18 | ||
| Sheathed insulated wires, single or multi-core sheathed cables in voids in building structures | 21 | |
| 22 | ||
| Single or multi-core cables in pipes in the voids of building structures | ;22A | |
 |
23 | |
 |
Single or multi-core cables in special boxes in the voids of building structures | 23A |
 |
24 | |
 |
Single or stranded cables in special masonry boxes | 24A |
| - | Sheathed single or stranded cables: | - |
| - laid in the voids of the ceiling - in double floors | - | |
| - | >Insulated wires, single or stranded cables in ducts on the wall: | - |
 |
31, 31A | |
 |
32, 32A | |
 |
Insulated wires in boxes recessed flush into walls or floors | 33 |
 |
Single or stranded cables in ducts recessed flush into walls or floors | 33A |
 |
34 | |
| - | Single or stranded cables in suspended boxes | 34A |
 |
Insulated wires in pipes laid in horizontal or vertical closed cable ducts | 41 |
 |
42 | |
 |
Sheathed cables, solid or stranded, in horizontal or vertical open or ventilated cable ducts | 43 |
| Sheathed insulated wires, multi-core sheathed cables embedded directly into walls | 51 | |
| - | Sheathed insulated wires, single or multi-core sheathed cables, embedded directly into the masonry: | - |
 |
- | |
 |
53 | |
| Sheathed cables, single or multi-core, in pipes or in special ducts in the ground | 61 | |
 |
Sheathed cables, solid or stranded in the ground: | 62 |
| - | ||
| 63 | ||
| 71 | ||
| Insulated wires and cables in plinth boxes * Space for communication cables and computer networks | 72 | |
| - | Insulated wires in pipes or sheathed cables, solid or stranded, laid: | 73 |
 |
- | |
 |
74 | |
 |
Sheathed cables, solid or stranded, laid in water | 81 |
521.6 Wiring in pipes and ducts
It is permitted to lay several circuits in the same conduit or conduit, provided that all wires are insulated for the highest rated voltage of the circuits laid in this conduit or conduit.
522 Selection and installation of electrical wiring depending on external influences
Notes
1 This section considers only those of the external influences specified in GOST R 50571.2, which significantly affect the wiring.
2 Specific operating conditions for electrical wiring in terms of the impact of external climatic factors (VVF) are established in accordance with GOST 15150 and GOST 15543.1 in accordance with one of the types of climatic performance specified in 321 GOST R 50571.2.
522.1 Ambient temperature (321.1 GOST R 50571.2)
522.1.1 The selection and installation of electrical wiring must be made in such a way that it is suitable for operation at the highest local ambient temperature in accordance with 5.4 and 5.5 of GOST 15150.
In this case, the upper and lower temperatures during the operation of the electrical wiring must be set in accordance with Appendix 4 of GOST 15543.1.
522.1.2 Various components of electrical wiring, including cables and all accessories, must be mounted only at those temperatures that are specified in the relevant standards for specific types of products or given by the manufacturer in accordance with 1.3 of Appendix 4 of GOST 15543.1.
522.2 External heat sources
522.2.1 To protect electrical wiring from heating by external heat sources, one of the following or other methods of equal effectiveness shall be used:
- shielding;
- removal of electrical wiring from heat sources at a sufficient distance;
- the choice of electrical wiring, taking into account the additional temperature increase that may occur;
- local reinforcement of the insulation or replacement of the insulation material. If it is not possible to eliminate additional heating by the above methods, correction factors for the temperature of the soil, water or air are applied, taking into account section 3 of Appendix 3 of GOST 15543.1.
NOTE Heat from external sources can be transferred by radiation, convection or conduction:
- from hot water supply systems;
- from appliances and lamps;
- as a result of the technological process;
- through heat-conducting materials;
- from radiation from the sun or the environment.
522.3 Presence of water (321.4 GOST R 50571.2)
522.3.1 Electrical wiring should be selected and installed so that water ingress will not cause damage. The installed electrical wiring must have an IP degree of protection corresponding to its location.
Notes
NOTE 1 In principle, intact sheaths and cable insulation in fixed installations can be considered sufficient protection against the ingress of moisture. Cables subject to frequent splashing, flooding or immersion in water require special consideration.
2 Damage to electrical wiring should be understood as electrical breakdown of insulation and mechanical damage to its shells or insulation.
522.3.2 Provision should be made for the removal of water or condensate where it may accumulate.
522.3.3 Where electrical wiring may be exposed to waves (AD6), its protection against mechanical damage must be ensured by one or more of the methods provided for in paragraphs 522.6, 522.7 and 522.8.
522.4 Presence of external solid bodies (321.5 GOST R 50571.2)
522.4.1 Wiring should be selected and installed in such a way as to minimize the risk of ingress of foreign solid particles. The installed electrical wiring must have an IP degree of protection corresponding to its location.
522.4.2 Where there is a significant amount of dust (AE4), additional measures should be taken to prevent the accumulation of dust or other particles in quantities that could adversely affect the processes of heat removal from the wiring.
NOTE It may be necessary to use a type of wiring that facilitates the removal of dust (see section 529).
522.5 Exposure to corrosive and polluting substances (321.6 GOST R 50571.2)
522.5.1 Where the presence of corrosive or contaminating substances, including water, may cause corrosion or deterioration of electrical wiring, parts of the wiring that may be damaged shall be suitably protected or made of materials resistant to such substances.
Note: Protective tapes, paints or lubricants may be acceptable additional protection during installation.
522.5.2 Contact of dissimilar metals causing electrolytic processes should be avoided unless special measures are taken to prevent the consequences of such contact.
522.5.3 Materials liable to cause mutual or individual deterioration in their quality shall not be in contact with each other.
522.6 Impacts (321.7.1 GOST R 50571.2)
522.6.1 Wiring should be selected and installed so as to minimize damage from mechanical external influences.
522.6.2 In fixed installations which may be subjected to the shocks specified for conditions M43 during operation, adequate protection may be provided:
- the mechanical characteristics of the wiring, or
- the choice of its location, or
- by additional local or general mechanical protection, or
- a combination of the above methods.
522.7 Vibration (321.7.2 GOST R 50571.2)
522.7.1 Wiring laid on the structures of equipment subject to vibration of medium or high hardness (M5, M6, M43 GOST 17516.1) or fixed on them must comply with these conditions. This is especially true for cables and their connections.
NOTE Particular attention must be paid to connecting electrical wiring to vibrating equipment. Local measures such as flexible electrical wiring may be used for this.
522.8 Other mechanical effects
522.8.1 Electrical wiring must be selected and installed in such a way as to prevent damage to the sheath and insulation of cables or insulated conductors, as well as their connections during installation and operation.
522.8.1.1 For concealed wiring in building structures, pipes or special cable ducts shall be fully assembled for each circuit before insulated wires or cables are tightened into them.
522.8.1.2 The bending radius of wires and cables shall be such as not to damage them.
522.8.1.3 When laying wires and cables on supporting structures with support at a certain distance, the latter must be such as to prevent damage to wires and cables from its own weight.
522.8.1.4 For locations where the wiring is subjected to a constant (e.g. tensile load in vertical sections of the route from its own weight), the appropriate type of cable or conductor of the required cross section and method of installation should be selected so as to prevent damage to the conductors and cables from their own weight.
522.8.1.5 Wiring in which the pulling in and out of wires or cables is intended shall be provided with appropriate means of access to carry out such an operation.
522.8.1.6 Electrical wiring in floors shall be adequately protected to prevent damage during normal use of the floor.
522.8.1.7 Wiring, rigidly fixed and embedded in the walls, must be located horizontally, vertically or parallel to the edges of the walls of the room.
Electrical wiring laid in building structures without fastening can be located along the shortest path.
522.8.1.8 Flexible wiring shall be installed in such a way that excessive tensile forces are not applied to the wires and connections.
522.9 Presence of flora and/or mold (321.8 GOST R 50571.2)
522.9.1 In places where such a danger exists or may occur (AK2), an appropriate type of electrical wiring should be selected or special protective measures should be taken.
NOTE It may be necessary to use a method of installation that will allow the removal of emerging vegetation or mold (see section 529).
522.10 Presence of fauna (321.9 GOST R 50571.2)
522.10.1 For locations where such a hazard exists or can be expected, the appropriate type of wiring must be selected or special protective measures provided, for example:
- selection of electrical wiring with appropriate mechanical characteristics or
- selection of an appropriate location, or
- application of additional local or general mechanical protection, or
- a combination of the above methods.
522.11 Solar radiation (321.11A GOST R 50571.2)
522.11.1 In places where there is significant solar radiation, the appropriate type of wiring should be selected for these conditions or the necessary shielding should be provided.
NOTE See also 522.2.1 regarding elevated temperature.
522.12 The impact of seismic factors (321.12 GOST R 50571.2)
522.12.1 When selecting and installing electrical wiring, the seismic hazard of the installation site should be taken into account.
522.12.2 Where there is a risk of seismic action, particular attention shall be given to:
- fastening electrical wiring to the building structures of buildings, taking into account the mechanical impact on the electrical wiring during the most unfavorable (from seismic vibrations with accelerations according to Appendix 6 of GOST 17516.1) mutual movements of building elements;
- connections of fixed electrical wiring to the main equipment. For example, for security systems, an appropriate degree of flexibility in connection of electrical wiring must be provided.
522.13 Air movement (321.14 GOST R 50571.2)
522.13.1 See paragraphs 522.7 and 522.8.
522.14 Building structure (CB1, CB2, CB3, CB4) (323.2 GOST R 50571.2)
522.14.1 Where building structures can move relative to each other (CB3), the fastening of wires and cables and their mechanical protection should allow such a relative displacement that does not subject the wires and cables to excessive mechanical stress.
522.14.2 In buildings with flexible or unstable structures (CB4), flexible electrical wiring should be used.
Note - See paragraphs 522.7, 522.8, 522.12.
523 Permissible current loads (GOST R 50571.2, IEC 364-5-523)
524 Conductor cross-sections
524.1 The cross sections of phase conductors in a.c. circuits and current-carrying conductors in direct current circuits shall not be less than the values specified in table 52J.
524.2 The cross section of the neutral conductor and the PEN conductor, if any, shall be the same as that of the phase conductors:
- in single-phase two-wire circuits, regardless of the section;
- in multi- and single-phase three-wire circuits with a cross section of phase conductors less than or equal to 16 mm for copper and 25 mm for aluminum conductors.
524.3 In multi-phase circuits in which the cross section of each phase conductor exceeds 16 mm 2 for copper and 25 mm 2 for aluminum conductors, the neutral conductor may have a smaller cross section than the phase conductors, while simultaneously fulfilling the following conditions:
- the expected maximum current, including harmonics, if any, in the neutral conductor during normal operation does not exceed the current carrying capacity for the reduced section of the neutral conductor.
NOTE The load on the circuit during all normal use should be distributed almost evenly between the phases;
- the neutral conductor is protected from overcurrents in accordance with the requirements of 473.3.2 GOST R 50571.8;
- the cross section of the neutral conductor and the PEN conductor is at least 16 mm for copper and 25 mm for aluminum conductors.
Table 52J- Minimum cross-sections of conductors
| Wiring types | Purpose of the chain | Conductor | ||
|---|---|---|---|---|
| - | Material | Section, mm | ||
| Cables and insulated conductors | Power and lighting circuits | Copper Aluminum | 1.5 2.5 (see note 1) | |
| Stationary electrical | Copper | 0.5 (see note 2) | ||
| installations | Bare conductors | Power circuits | Copper Aluminum | 10 16 |
| Signaling and control circuits | Copper | 4 | ||
| Flexible connections with insulated | Internal installation in devices and devices | According to the norms and requirements of the relevant standards | ||
| conductors and cables | In other cases | Copper | 0.75 (see note 3) | |
| In extra-low voltage circuits for special applications | 0,75 | |||
Notes
NOTE 1 Terminations used to terminate aluminum conductors shall be tested and designed for this purpose.
2 For signaling and control circuits intended for electronic equipment, the minimum allowable conductor cross-section is 0.1 mm
3 Note 2 also applies to multi-core flexible cables with seven or more cores.
525 Voltage losses in electrical installations of buildings
Note - Voltage losses in electrical installations of buildings should not exceed 4% of the rated voltage of the installation. Temporary conditions such as transients and voltage fluctuations caused by incorrect (erroneous) switching are not taken into account.
526 Electrical connections
526.1 Connections of conductors to each other, as well as their connection to equipment, shall ensure the constant electrical conductivity of the circuit and adequate mechanical strength and protection.
526.2 In choosing the method of connection, the following shall be considered accordingly:
- material of the conductor and its insulation;
- the number and shape of the wires forming the conductor;
- cross section of the conductor;
- the number of conductors that will be connected together;
- environmental conditions and areas of premises for explosion and fire hazard.
NOTE Soldering of power conductor connections should be avoided. However, if such connections are used, they should be made taking into account possible displacements and mechanical effects (see paragraphs 522.6-522.8).
526.3 All connections shall be accessible for their inspection, testing and maintenance, except for the following connections:
- cable connections in the ground;
- joints filled with compound or sealed;
- connections of cold ends with heating elements of floor and ceiling heating systems.
526.4 Where necessary, care shall be taken to ensure that the temperature of the connections during normal use does not impair the insulation of the conductors connected to or supporting them.
527 Selection and installation of electrical wiring under the conditions of limiting the spread of combustion
527.1 Precautions within a separate space enclosed by fire-resistant building structures
527.1.1 The risk of fire propagation can be reduced by selecting appropriate materials and installation methods in accordance with the requirements of GOST 12.1.004, GOST 12.2.007.0, GOST 12176 and the requirements set out in paragraph 522 of this standard.
527.1.2 Installation of electrical wiring should not reduce the performance of building structures and fire safety.
527.1.3 Cables and other wiring elements that have the necessary fire resistance specified in the relevant standards may be used without any additional precautions.
NOTE In electrical installations where there are special fire hazard conditions, it may be necessary to use special types of wires and cables.
527.1.4 The use of cables that do not meet at least the requirements of the standards for limiting their ability to spread fire should be limited to small lengths for connecting electrical appliances to permanent electrical wiring networks and in any case should not be allowed between rooms separated by fireproof partitions.
527.1.5 Wiring elements, other than cables, that do not meet at least the requirements of the relevant standards for the ability to propagate combustion, but in all other respects comply with the requirements of the standards, must be placed completely in a sheath of non-combustible materials or protected (covered, painted) with non-combustible materials.
527.2 Sealing of wiring passages
527.2.1 When electrical wiring passes through structural elements of buildings and structures, such as floors, walls, roofs, ceilings, partitions, the fire resistance of which is determined by the project, the remaining holes must be sealed with a degree of fire resistance equal to the fire resistance of the corresponding elements of building structures.
527.2.2 Electrical wiring made in pipes, special channels, ducts, busbars or busbars that pass through structural elements of buildings with established fire resistance must have an internal seal that provides the same fire resistance as the corresponding building structural elements. Likewise, they must be sealed from the outside, as required by paragraph 527.2.1.
527.2.3 The requirements of 527.2.1 and 527.2.2 are considered satisfactory if the wiring seal has been type tested.
527.2.4 Wiring in pipes and conduits, in which materials are used that comply with the requirements of the fire propagation standard and have a maximum internal section of 710 mm, may not be sealed from the inside, provided that:
- wiring has a degree of protection not lower than IP33;
- any termination of the electrical wiring has a degree of protection not lower than IP33.
527.2.5 No electrical wiring may pass through the structural members of a building unless the integrity of those structural members of the building cannot be ensured after the installation of the electrical wiring.
527.2.6 Seals made in accordance with the requirements of 527.2.1 and 527.2.3 shall comply with the requirements of 527.3 and the notes below.
Notes
1 These requirements can be classified as material standards if such standards are developed:
- the materials used must be compatible with the wiring materials with which they are in contact;
- they must allow thermal movement of electrical wiring elements without compromising the quality of the seal;
- they must have adequate mechanical strength to withstand the stresses that may result from damage to the supporting structures of electrical wiring as a result of fire.
2 Compliance with the requirements of this subclause can be ensured if:
- cable fastening or support structures are located within 750 mm of the pressure seal and are capable of withstanding the mechanical stresses expected in the event of a fire failure of the cable fasteners from the fire side so that the seal is not subjected to additional stress;
- or the design of the sealing device itself provides its necessary strength.
527.3 External influences
527.3.1 Seals designed to meet the requirements of 527.2.1 and 572.2.2 shall withstand external influences to the same extent as the wiring itself for which they are used, and, in addition, they shall meet the following requirements:
- withstand the impact of combustion products with the same degree calculated for structural elements of buildings through which electrical wiring passes;
- provide the same degree of protection against water penetration required from structural elements of buildings in which they are made;
- the electrical wiring seal must be protected from water running along the electrical wiring or collecting around the seal, unless the materials used for the seal are waterproof.
527.4 Mounting conditions
527.4.1 Temporary sealing may be required for electrical wiring.
527.4.2 During wiring work, the seal must be repaired as soon as possible.
527.5 Inspection and testing
527.5.1 Seals shall be checked to ensure that they are made in accordance with the installation instructions.
527.5.2 After this verification, no further tests are required.
528 Rapprochement with other engineering networks
528.1 Proximity to electrical networks
528.1.1 Electrical circuits with voltage ranges I and II according to GOST R IEC 449-96 must not be located in the same wiring, unless each cable has insulation designed for the maximum voltage present in this wiring, or if at least one of the following conditions:
- each conductor of a multicore cable is insulated for the maximum voltage in the cable, or
- cables with insulation for different voltages are mounted in separate sections of special cable channels or ducts, or - laying is used in different pipes.
NOTE Special consideration may be required for the possible effects of electromagnetic and electrostatic interference on communication lines, computer networks, and similar networks.
528.2 Proximity to non-electric networks
528.2.1 Wiring should not be installed near sources of heat, smoke, or steam that may adversely affect them, unless they are protected from such exposure by appropriate shielding to prevent heat from being removed from them.
528.2.2 Where electrical wiring runs under networks subject to condensation (such as water, steam or gas networks), measures should be taken to protect the wiring from their harmful effects.
528.2.3 Where electrical networks are located near non-electrical networks, they must be located so that any intended operation on these networks would not harm the electrical networks and vice versa.
Note - This can be achieved:
- placing networks at a sufficient distance from each other;
- use of mechanical and thermal shielding.
528.2.4 Where electrical networks are located close to other networks, the following conditions must be met:
- electrical wiring must be well protected from the harmful effects of other networks during their normal operation;
- protection against indirect contact must be provided in accordance with the requirements of GOST R 50571.3, while non-electric metallic networks should be considered as third-party conductive parts.
529 Selection and installation according to maintenance conditions, including cleaning
529.1 The selection and installation of electrical wiring should take into account the knowledge and experience of the people who are expected to maintain the system.
529.2 If it is necessary to remove protective equipment for repair or maintenance, ensure that they are immediately restored to their original condition.
529.3 Safe and convenient access to all electrical wiring items that may require maintenance or repair should be provided.
Note - In some cases, it is necessary to provide means of permanent access to electrical wiring in the form of ladders, bridges, etc.
APPENDIX A
(reference)
AUTHENTIC TEXT OF ITEMS (PARAGRAPHS) OF IEC 364-5-52-93, THE REQUIREMENTS FOR WHICH ARE REFINED IN THIS STANDARD
The authentic text of clauses (paragraphs) of IEC 364-5-52-93, for which changes have been made to the corresponding clauses of this standard, are given in Table A. 1.
Table A1
| Section number, paragraph (paragraph) | Authentic IEC 364-5-52 text | |
|---|---|---|
| this standard | IEC 364-5-52 | |
| 522.1.1 | 522.1.1 | 522.1.1 The selection and installation of electrical wiring is carried out taking into account the highest values of ambient temperature. However, the temperature limit specified in Table 52A of IEC Publication 523 shall not be exceeded (clauses and subclauses of IEC Publication 321 and IEC 323 are given in IEC 364-3) |
| 522.6.2 (first paragraph) | 522.6.2 (first paragraph) | 522.6.2 In fixed installations which may be subjected to moderate (AG2) or severe (AG3) impacts during operation, adequate protection may be provided. |
| 522.7.1 (first paragraph | 522.7.1 (first paragraph) | 522.7.1 Wiring connected to or attached to equipment subject to medium (AH2) or high vibration (AH3) shall comply with these conditions. |
| 522.12.2 | 522.12.2 | 522.12.2 In places with reduced (AP2) or increased seismic hazard, special attention must be paid to: - fixing electrical wiring to building structures; - connections of fixed electrical wiring with all nodes of the main equipment, i.e. ensuring the flexibility of these connections. |
APPENDIX B
GUIDELINES FOR VERIFICATION OF WIRING RESISTANCE TO SPECIAL ENVIRONMENTS
The following provisions apply for preliminary verification of the conformity of the resistance of electrical wiring with the requirements for operation in conditions of exposure to special environments (see 522.5):
B1 The assessment of the resistance of electrical wiring is carried out at the stage of research and development work on the development of its typical units (which corresponds to acceptance or preliminary tests in accordance with GOST 16504).
B2 The resistance of electrical wiring elements according to 522.1.2 can be verified by tests in accordance with GOST 24683.
B3 If it is required to check the electrical wiring by testing according to the GOST 24683 modes, then the mock-ups or its individual critical nodes in full size are subjected to tests.
B4 The test of electrical wiring according to clause B3 is not carried out if the elements included in it meet the requirements of 522.5.1 and 522.5.2, and its design features are such that the connection of the elements into a system does not change the parameters of the elements or the electrical wiring as a whole in terms of resistance to special environments .
B5 It is allowed not to test the electrical wiring according to paragraph B3, if the requirements of paragraphs B. 5.1 and B. 5.2 are met:
B. 5.1 Electrical wiring is designed for operation in gas and vapor environments of group 5 according to GOST 24682 at effective values of their concentration less than 0.4 MPC (and for SO2, H2SO4, CO2 - 0.8 MPC), while the resistance of electrical wiring can be guaranteed the use of resistant materials and coatings in accordance with GOST 9.303.
B. 5.2 The impact of special environments on electrical wiring under operating conditions will occur for half or less of its established service life.
Key words: electrical installations of buildings; choice of electrical equipment; installation of electrical equipment; electrical wiring; lighting and secondary networks; busbars; AC circuits; installation method; the wire; cable; permissible current loads; cross-sections of conductors; voltage loss; electrical connections; sealing of electrical wiring passages; proximity to electrical networks
The term electrical wiring should be understood as a system of electrical cables and wires in conjunction with the elements used to fix and protect them, mounted in accordance with applicable standards (PUE, in particular). The requirements for electrical wiring, as well as the procedure for its installation, are presented in these documents in the form of a set of recommendations for choosing the main parameters (type, section, etc.) and the procedure for laying electrical wires. At the same time, the specific content and scope of these requirements depend not only on the conditions of electrical installation, but also on the type of wiring being installed.
Types of wiring
Any electrical wiring, depending on the conditions in which it is laid, is divided into internal wiring, located within habitable and utility rooms, and external, mounted outside these boundaries.
Please note: The second category also includes wire systems laid between buildings on supports and under canopies (away from roads).
According to the method of installation, all known types of electrical wiring are divided into open, placed on the surfaces of walls and ceilings, and closed, laid in the structural elements of the interior or under the interior walls.
Open wiring can be carried out in the form of freely hanging wires (cable lines) fixed on cables and steel strings or on special insulating rollers. The same type should include wiring mounted in boxes, pipes and flexible hoses, as well as in platbands and skirting boards equipped with a special channel for its placement. Note that some communication lines are laid in a similar way (communication cables, in particular).
Closed wiring is mounted inside structural elements (in walls, ceilings, floors and in foundation screeds). At the same time, it is necessarily placed in flexible metal sleeves laid in the voids of concrete structures, as well as in strobes, subsequently covered with a layer of plaster. In addition, enclosed wiring can be routed under decorative trim.
General requirements
Requirements for the selection of the cross section of wires and cables
When choosing the cross section of wires and cables in the wiring, one should proceed from the data in the table given in Table No. 1. When working with it, you must consider the following points:
- the table shows averaged data, which in each case are determined by the power in the load and may have different values;
- when choosing the type and section of wires, the conditions for their laying, determined by the safety category (group) of the serviced object, should be taken into account;
- in addition, in some cases, such a choice is subject to special requirements regulated by fire safety standards (for electrical wiring in a wooden house, in particular).
Table 1. The value of the cross sections of conductive wires
Let's consider each of these points in more detail.
The choice of specific values of permissible wire cross-sections should be made taking into account the currents acting in individual linear wiring circuits and determined in accordance with the power of the equipment connected to them (see table No. 2). For the convenience of choosing and calculating this parameter, experts advise preparing a wiring diagram before installation indicating the load currents of individual consumer devices on it (the current load in the circuit is determined as the result of dividing the power in the load by the voltage acting in it). You can find all the values of electrical parameters necessary for such a calculation in the documentation for the connected equipment.
As for the dependence of the type of wires used on the conditions of their installation, before considering it, you should familiarize yourself with the classification of the latter according to the degree of danger. According to this indicator, all residential and non-residential facilities are divided into the following categories (there are nine in total):
- Dry (heated or unheated) in which the relative humidity is less than 60% and the average temperature does not exceed 30°C. At the same time, they do not contain chemically active media and accumulations of conductive dust. Living rooms in the house should also be included in this category.
- Dusty with a large amount of conductive dust, which is able to settle on wires, as well as penetrate into equipment and electrical installations. This category also includes storage areas with bulk materials stored on them.
- Wet (bathrooms, kitchens, unheated warehouses), in which, as a result of vaporization, strong moisture is created, but at the same time, the relative humidity of the air does not exceed 60–75%.
- The so-called "raw" buildings, where the air humidity exceeds 75% for a long time (vegetable storage, for example).
- Especially raw, in which the same indicator is close to 100%; at the same time, droplets of moisture settle on the ceiling, floor, walls and objects placed inside. This category includes sheds, greenhouses, greenhouses, utility and unheated buildings.
- Another danger group is made up of premises with a chemically active or organically hazardous environment (chemical warehouses, fertilizer storage facilities, poultry houses and special areas for keeping animals).
- The seventh, eighth and ninth hazard groups include especially hot, fire hazardous and explosive objects (baths, saunas, warehouses of combustible materials and ammunition, etc.).
The last group can also include all wooden buildings in which special measures must be taken to protect the structure from fire during the wiring process.
Table 2. Selection of the cross section of the cable cores depending on the load current
Wiring Requirements
Installation of electrical wiring is carried out in accordance with the current regulations (see SNiP), which regulate the procedure for laying cables and bundles in specially designated places and channels. As such places for placing electrical wiring in the house can be used:
- walls and ceilings of living rooms;
- special niches in building structures;
- cable ducts hidden in the elements of decorative trim (skirting boards, platbands);
- special cable channels and boxes.
The rules for installing electrical wiring in a house allow the use of separate insulated conductors, for laying which are most often used:
- metal or plastic pipes;
- plastic boxes or corrugated sleeves;
- special decorative insulators.
In this case, the wiring of individual wires is prohibited in the following places:
- in a hidden form (in strobes under plaster, for example);
- in the voids of building structures of panel-type houses;
- in open form (on the surface of ceilings and walls, in trays, etc.).
Features of installation of cable lines
When considering the requirements for laying cable lines, it is necessary to pay attention to the following circumstance. Their installation within the building is carried out taking into account the general requirements already considered by us, with the exception of the case of laying cables in trenches, carried out when organizing an underground input of a power line to an object.
The rules for laying a cable in a trench, regulated by the relevant provisions of SNiP, pay attention to the following features of this type of wiring:
At the point where the electric cable is entered into the building being serviced, the latter must be protected by a special asbestos-cement sleeve that passes directly through the wall or foundation and protrudes from each side by at least 60 cm.
- Throughout the underground communication, the cable line is covered with brickwork, which protects the input from soil subsidence.
- When laying electrical cables from various supply substations in one trench, the distance between them is strictly standardized (in accordance with the requirements of SNiP, it must be at least 50 cm).
- The depth of the cable laying is selected depending on the freezing index of the soil and the proximity of groundwater in the area, as well as taking into account the deepening of the foundation of the house.
- The current SNiP regulate this indicator at a level of at least 75 cm and allow for the possibility of its upward adjustment.
Please note: All of the above requirements apply only to low-power power cables laid when it is impossible to organize the so-called "overhead" line (VL).
Thus, for the correct arrangement of the entrance to the house, you should strictly adhere to all the above rules and not violate the generally accepted order of installation procedures. In more detail, the technology of laying cables in underground conditions is described in the source cited at the end of the article.
Putting the electrical wiring into operation
Upon completion of the entire range of electrical installation work carried out on its own or with the involvement of a third-party contractor, their acceptance is organized by a commission consisting of representatives of local power grids and Energosbyt specialists. Based on the results of the inspection of the electrical wiring, the members of the commission draw up an acceptance certificate, in which all the shortcomings made by the contractor (violations of the requirements of SNiP) are necessarily recorded and recommendations are given for their prompt elimination.
In the absence of serious comments, as well as after the elimination of all shortcomings, the members of the commission sign an act on the acceptance of this facility and its commissioning.
In conclusion, we note once again that regardless of the purpose of the electrical wiring (whether it is done for the installation of equipment or for the purpose of supplying a certain object), its commissioning is possible only if the contractor complies with all the regulations mentioned in the article.
Replacing or installing new electrical wiring in residential premises today is difficult to imagine without a thorough study of all the details of the new electrical network. In most cases, such detailing is comparable to a full-fledged design. And although previously a separate power supply project for an apartment was developed extremely rarely, today it is an important addition to the technical passport of an apartment or townhouse.
We note right away that there is no unambiguous legislative wording stipulating the mandatory development of a full-fledged electrical project for private apartments. But on the other hand, there are quite strict rules governing the process of connecting a new electrical wiring of an apartment to the power line of a house.
In order to pass without problems all stages of approvals, it is necessary that the electrical network of the residential premises be displayed in compliance with the rules and regulations. In addition, do not forget that the presence of a full-fledged project will greatly simplify further repairs and the connection of new equipment.
First of all, we recall that from the point of view of the PUE, an apartment electrical network is an electrical installation and is subject to the general rules for connecting and operating electrical systems.
For the developer or owner of the apartment, this means that two main factors must be officially confirmed before being admitted to the technological connection to the electrical network of the house:
- compatibility of internal wiring with an external power supply (in terms of power and in terms of protection against short circuits);
- safety for people who will live in the apartment (electrical and fire).
In addition, private consumers of electricity, as a rule, are connected to the distribution network through electricity meters, which means that the connection must be coordinated in one more instance - in the power supply company.
At the same time, several government decrees are currently in force (No. 334 of 2009 and No. 640 of 07/29/2013), according to which project documentation for the electrical network of an apartment is not subject to approval by the grid company. The approval of the electrical project in Rostekhnadzor is also not required.
Theoretically, this means that a simplified connection procedure applies to apartments, therefore, to connect to a power line, it is enough to obtain permission from the management company and conclude an agreement with Energosbyt. In the first case, it is necessary to provide a single-line power supply diagram for the apartment, in the second - a connection diagram for metering devices.
But in practice, each of the reviewing authorities requires documentation that meets generally accepted standards, any deviation from which will be regarded as a reason for refusing to consider the application.
Whether a power supply project is needed, whether or not it is worth starting a conflict with the management company and Energosbyt, insisting on the correctness of independently calculated schemes, is everyone’s personal business, but the complexity of the power supply networks of modern apartments has long crossed the level when professional design is not only desirable, but also necessary.
The structure of the apartment electrical network
From the point of view of electrical design, an apartment is a rather complex object with an extensive list of diverse properties. Therefore, the first task that the designer solves is to determine the topology of the internal network.
In general, wiring can be of three types:
- through junction boxes (for two-room, three-room, etc.);
- from individual machines in the switchboard (for one-room apartments);
- mixed version ("loop").
Most often, the first option is used in apartments, in which different branches of the circuit are switched through junction boxes.
The choice of a specific network topology depends on various factors, but in any case, the costs of wire and wall chasing should be taken into account.
In addition to the topological division, typical projects use the division into groups according to functional features:
- lighting;
- common group sockets;
- power sockets for powerful electrical appliances;
- electrical network for connecting electrical equipment in the bathroom;
- kitchen network.
Note that the distribution by functional attribute is done for the following reasons:
- to improve the reliability of the entire network (a short circuit in the subnet does not de-energize the entire network);
- for more precise adjustment of protection systems (different RCD sensitivity);
- to make it possible to use less powerful wires.
Security
Under the security of the apartment power supply network, they mean the level of protection of people living in the apartment from electric shock, as well as the fire and mechanical stability of the electrical wiring.
Note that by modern standards, the safety of wiring in Khrushchev, Brezhnevka and even in apartments of panel houses is very low, since in Soviet times such houses did not provide a ground wire for internal subnets.
Today, the standard "arsenal" of fire and electrical safety includes the following devices and activities:
- devices for automatic shutdown in case of short circuits in the internal network;
- main and additional potential equalization systems;
- grounding according to the TN-C-S scheme;
- differential current difference control devices (RCD).
The necessary level of safety of the electrical network is ensured not only by hardware, but also by the regulation on permissible electrical materials (fire-resistant grades of wires and cables, special types of corrugated hoses, etc.).
It should also be taken into account that fire and electrical safety directly depends on the mechanical stability of the electrical wiring elements, so the network is assembled in compliance with the following rules:
- laying electrical wiring in an apartment passing through the walls in the transverse direction is carried out using a rigid metal pipe (which must be indicated in the project);
- assembly of switching units is carried out using special terminal blocks or a device for contact welding (twisting is not allowed!).
From the point of view of design, a distinction is made between the main and additional protection systems.
The main system includes circuit breakers and basic potential equalization systems, and their location is indicated on a single-line circuit diagram. As an additional measure aimed at improving electrical safety, an additional potential equalization circuit may be included in the electrical project (drawn up on separate drawings).
Where to start?
The development of an electrical project for apartments begins with obtaining technical conditions for connection and with determining the boundaries between areas of responsibility. These two documents are issued by the management company, on whose balance sheet the distribution network of the house is located.
The technical conditions stipulate the measures that the subscriber must perform before connecting to the network, as well as the main parameter - the maximum power consumption.
Please note that according to modern standards, the range of allocated power per apartment is from 4.5 to 15 kW. Oddly enough, but some management companies are guided by the standards for buildings built in the 70-80s of the last century, and when obtaining specifications, this parameter must be controlled, since it is often unreasonably low.
A more detailed description is given in SP 31-110-2003 (tables 6.1 and 6.2) where the design loads for multi-apartment residential buildings are given:
- for apartments with natural gas stoves - at least 4.5 kW;
- for apartments with electric stoves with a power of 8.5 kW - at least 10 kW;
- in superior apartments - at least 14 kW.
In fact, an electrical technical specification is a sketch that indicates the places where the lamps, switches and all consumers of electricity that are supposed to be installed in the apartment will be located.
After the TOR is drawn up, all three source documents are transferred to designers who perform the calculation of technical parameters and the development of related schemes.
As mentioned above, the development of technical specifications for electrification for 1-2 x and 3-room apartments is a rather complicated operation that requires an understanding of some basic dependencies and norms.
The development is based on the plan of the apartment and taking into account the design of the project (if any). Pay attention to an important point - if there is no project design, then it must be done, at least in a sketch form. This is necessary to determine the locations of the main consumers of electricity.
When drawing up a TK plan, you should use the symbols recommended in GOST 21.614-88 (sample in the figure on the left). The use of standard symbols on the sketch is necessary so that the task is understandable to the engineers who will perform the design.
First, the positions of the lamps and the direction of opening the doors are plotted on the diagram.
It is important to consider that the switches should be located so that they are easily accessible immediately after entering the room (that is, they are not blocked by an opening door).
Note that this rule does not apply to bathrooms - in these cases, the switches are located outside the room.
The position of the sockets is marked in the same way.
After the main points of "distribution" of electricity are determined, it is necessary to determine the location of the junction boxes.
The next stage - drawing up a connection diagram - is the most important, since the following prerequisites must be taken into account when performing it:
- if the building is monolithic - it is strictly forbidden to violate the integrity of the supporting structures;
- strobe planning for wires should be performed only in orthogonal directions;
- it is not recommended to place the wire laying line above the windows, since in this case a breakdown of the cable is likely when fittings are installed under curtains or curtains;
- it is recommended to connect sockets directly from junction boxes (not a loop, so as not to reduce the throughput of the last socket).
When drawing connection lines on the layout, each wire is drawn separately.
In some cases, you can reduce the amount of wall chasing work by planning to lay the wire inside floor slabs or in corrugated pipes above the false ceiling.
The development of a sketch of the TK is being completed by connecting the junction boxes to the input shield.
The result should be a diagram of the following form:
What is calculated
The initial data for the design design stage are technical specifications (TS), terms of reference (discussed in the previous section), and an act of delimitation of balance sheet ownership.
At this stage, designers need to calculate the following data:
- design and installation capacity;
- lengths and sections of wires;
- limiting currents in subnets and ratings of circuit breakers;
- parameters of uninterruptible power supplies (if necessary);
- lighting network parameters (according to SNiP 23-05-95).
In the course of calculations, the methodological requirements specified in RM-2696 (instructions for calculating the electrical loads of residential buildings) and MGSN 4.19-2005 (design standards for high-rise buildings) should be taken into account.
A properly drawn up electrical project will allow you to quickly complete all electrical work and get the finished turnkey result.
The composition of the project documentation
After the development is completed, the project should include the following documents:
- explanatory note;
- single-line schematic diagram of power supply (switchboard diagram);
- outlet network plan;
- layout of electrical equipment;
- lighting network plan;
- specification.
Approval marks are put on a single-line diagram.
If redevelopment was carried out after commissioning, then all changes are reflected in the executive package of documentation.
The design of the explanatory note and drawings must comply with GOST 21.614-88.
At the end of the review, we emphasize once again that in modern conditions an apartment power supply project is necessary, first of all, by the homeowners themselves, since without a wiring diagram, troubleshooting and repairs will be extremely difficult.
The Mega.ru company accepts orders for the development of electrical projects for buildings and premises in Moscow and the Moscow Region, including the design of wiring in apartments and townhouses. You can clarify the details of cooperation and order a questionnaire using any type of communication published on the page.