PUE: . Laying cables through a wall

2006. Rules for electrical installations. Section 2. Electricity sewerage (41439)

PUE PUE:2006. Rules for electrical installations. Section 2. Electricity sewerage

1 A lining made of fireproof materials must protrude from each side of the wire, cable, pipe or box by at least 10 mm.

2 Plastering of the pipe is carried out with a continuous layer of plaster, alabaster, etc. thickness of at least 10 mm above the pipe.

3 A continuous layer of fireproof material around the pipe (box) can be a layer of plaster, alabaster, cement mortar or concrete with a thickness of at least 10 mm.

In museums, art galleries, libraries, archives and other storage facilities of national importance, wires and cables should only be used with copper conductors.

2.1.50. To power portable and mobile electrical receivers, cords and flexible cables with copper conductors should be used, specifically designed for this purpose, taking into account possible mechanical stress. All conductors of the specified conductors, including the grounding conductor, must be in a common sheath, braid or have common insulation.

For mechanisms that have limited movement (cranes, mobile saws, gate mechanisms, etc.), current supply structures to them should be used that protect the cores of wires and cables from breaking (for example, flexible cable loops, carriages for movable suspension of flexible cables).

2.1.51. If there are oils and emulsions in the places where the wires are laid, you should use wires with oil-resistant insulation or protect the wires from their influence.

OPEN ELECTRICAL CIRCUITING INDOOR PREMISES

2.1.52. Open laying of unprotected insulated wires directly on bases, on rollers, insulators, on cables and trays should be carried out:

1. At voltages above 42 V in rooms without increased danger and at voltages up to 42 V in any rooms - at a height of at least 2 m from the floor or service area.

2. For voltages above 42 V in high-risk and especially dangerous areas - at a height of at least 2.5 m from the floor or service area.

These requirements do not apply to descents to switches, sockets, starting devices, panels, lamps installed on the wall.

IN production premises runs of unprotected wires to switches, sockets, devices, panels, etc. must be protected from mechanical influences to a height of at least 1.5 m from the floor or service area.

In domestic premises industrial enterprises, in residential and public buildings, the specified slopes may not be protected from mechanical influences.

In rooms accessible only to specially trained personnel, the height of openly laid unprotected insulated wires is not standardized.

2.1.53. In crane spans, unprotected insulated wires should be laid at a height of at least 2.5 m from the level of the crane trolley platform (if the platform is located above the crane bridge deck) or from the crane bridge deck (if the deck is located above the trolley platform). If this is not possible, then protective devices must be installed to protect personnel on the trolley and crane bridge from accidentally touching the wires. Safety device must be installed along the entire length of the wires or on the crane bridge itself within the location of the wires.

2.1.54. The height of open laying of protected insulated wires, cables, as well as wires and cables in pipes, boxes with a degree of protection not lower than IP20, in flexible metal hoses from the level of the floor or service area is not standardized.

2.1.55. If unprotected insulated wires intersect with unprotected or protected insulated wires with a distance between the wires of less than 10 mm, then additional insulation must be applied to each unprotected wire at the intersection points.

2.1.56. When crossing unprotected and protected wires and cables with pipelines, the clear distance between them must be at least 50 mm, and with pipelines containing flammable or flammable liquids and gases - at least 100 mm. When the distance from wires and cables to pipelines is less than 250 mm, wires and cables must be additionally protected from mechanical damage for a length of at least 250 mm in each direction from the pipeline.

When crossing hot pipelines, wires and cables must be protected from exposure high temperature or must have an appropriate design.

2.1.57. When laying in parallel, the distance from wires and cables to pipelines must be at least 100 mm, and to pipelines with flammable or flammable liquids and gases - at least 400 mm.

Wires and cables laid parallel to hot pipelines must be protected from high temperatures or must be designed accordingly.

2.1.58. In places where wires and cables pass through walls, interfloor ceilings or where they exit outside, it is necessary to ensure the possibility of changing electrical wiring. To do this, the passage must be made in a pipe, box, opening, etc. In order to prevent the penetration and accumulation of water and the spread of fire in places of passage through walls, ceilings or exits to the outside, gaps between wires, cables and pipes (ducts, openings, etc.), as well as backup pipes (ducts, openings, etc.) should be sealed. .p.) easily removed mass from fireproof material. The seal must allow replacement, additional installation of new wires and cables and ensure the fire resistance limit of the opening is not less than the fire resistance limit of the wall (floor).

2.1.59. When laying unprotected wires on insulating supports, the wires must be additionally insulated (for example, with an insulating pipe) in places where they pass through walls or ceilings. When these wires pass from one dry or wet room to another dry or wet room, all wires of one line can be laid in one insulating pipe.

When passing wires from a dry or damp room to a damp one, from one damp room to another damp one, or when wires exit a room outside, each wire must be laid in a separate insulating pipe. When leaving a dry or damp room into a damp or outside building, wire connections must be made in a dry or damp room.

2.1.60. On trays, supporting surfaces, cables, strings, strips and other supporting structures, it is allowed to lay wires and cables close to each other in bundles (groups) various shapes(for example, round, rectangular in several layers).

The wires and cables of each bundle must be fastened together.

2.1.61. In boxes, wires and cables can be laid in multi-layered, ordered and arbitrary (scattered) mutual arrangement. The sum of the cross-sections of wires and cables, calculated by their outer diameters, including insulation and outer sheaths, should not exceed: for blind boxes, 35% of the clear cross-section of the box; for boxes with openable lids 40%.

2.1.62. Permissible long-term currents on wires and cables laid in bundles (groups) or multilayered must be taken taking into account reduction factors that take into account the number and location of conductors (cores) in the bundle, the number and mutual arrangement bundles (layers), as well as the presence of unloaded conductors.

2.1.63. Pipes, ducts and flexible metal hoses of electrical wiring must be laid so that moisture cannot accumulate in them, including from condensation of vapors contained in the air.

2.1.64. In dry, dust-free rooms, in which there are no vapors and gases that negatively affect the insulation and sheath of wires and cables, it is allowed to connect pipes, ducts and flexible metal hoses without sealing.

Connecting pipes, ducts and flexible metal hoses to each other, as well as to ducts, electrical equipment housings, etc. must be done:

in rooms that contain vapors or gases that negatively affect the insulation or sheathing of wires and cables, in outdoor installations and in places where oil, water or emulsion can get into pipes, boxes and hoses - with a seal; boxes in these cases must have solid walls and sealed solid covers or blind ones, detachable boxes must have seals at the joint points, and flexible metal hoses must be sealed;

in dusty rooms - with sealing of connections and branches of pipes, hoses and boxes to protect against dust.

2.1.65. The connection of steel pipes and boxes used as grounding or neutral protective conductors must comply with the requirements given in this chapter and Ch. 1.7.

HIDDEN ELECTRICAL WIRING INSIDE PREMISES

2.1.66. Hidden electrical wiring in pipes, ducts and flexible metal hoses must be made in compliance with the requirements given in 2.1.63-2.1.65, and in all cases with a seal. Concealed electrical wiring boxes must be solid.

2.1.67. Carrying out electrical wiring in ventilation ducts and mines is prohibited. It is allowed to cross these channels and shafts with single wires and cables enclosed in steel pipes.

2.1.68. Laying wires and cables behind suspended ceilings must be performed in accordance with the requirements of this chapter and Ch. 7.1.

ELECTRICAL WIRING IN THE ATTIC

2.1.69. IN attic spaces The following types of electrical wiring can be used:

open;

wires and cables laid in pipes, as well as protected wires and cables in sheaths made of fireproof or fire-resistant materials - at any height;

unprotected insulated single-core wires on rollers or insulators (in attics of industrial buildings - only on insulators) - at a height of at least 2.5 m; when the height of the wires is less than 2.5 m, they must be protected from touch and mechanical damage;

hidden: in walls and ceilings made of fireproof materials - at any height.

2.1.70. Open wiring in attic spaces should be carried out with wires and cables with copper conductors.

Wires and cables with aluminum conductors are allowed in attics: buildings with fireproof floors - when they are laid openly in steel pipes or hidden installation in fireproof walls and ceilings; industrial buildings for agricultural purposes with combustible floors - when they are laid openly in steel pipes, excluding the penetration of dust into the pipes and connecting (branch) boxes; in this case must be applied threaded connections.

2.1.71. The connection and branching of copper or aluminum conductors of wires and cables in the attic must be carried out in metal junction (branch) boxes by welding, crimping or using clamps corresponding to the material, cross-section and number of conductors.

2.1.72. Electrical wiring in the attic, made using steel pipes, must also meet the requirements given in 2.1.63-2.1.65.

2.1.73. Branches from lines laid in attics to electrical receivers installed outside attics are allowed provided that the lines and branches are laid openly in steel pipes or hidden in fireproof walls (floors).

2.1.74. Switching devices in circuits of lamps and other electrical receivers installed directly in attic spaces must be installed outside these rooms.

EXTERNAL ELECTRIC WIRING

2.1.75. Unprotected insulated wires of external electrical wiring must be located or fenced in such a way that they are inaccessible for touching from places where people may be frequently present (for example, a balcony, porch).

From the indicated places, these wires, laid openly along the walls, must be located at a distance of at least m:

For horizontal installation:

under the balcony, porch, and also above the roof

industrial building 2,5

under the window 0.5

under the balcony 1.0

under the window (from the window sill) 1.0

At vertical laying to window 0.75

The same, but up to the balcony 1.0

From the ground 2.75

When hanging wires on supports near buildings, the distance from the wires to balconies and windows must be at least 1.5 m with a maximum deviation of the wires.

External electrical wiring on residential roofs, public buildings and entertainment enterprises are not allowed, with the exception of inputs to buildings (enterprises) and branches to these inputs (see 2.1.79).

Unprotected insulated wires of external electrical wiring should be considered as uninsulated with regard to touch.

2.1.76. The distances from wires crossing fire passages and paths for the transportation of goods to the ground surface (road) in the roadway must be at least 6 m, in non-roadway areas - at least 3.5 m.

2.1.77. The distances between the wires must be: for a span of up to 6 m - at least 0.1 m, for a span of more than 6 m - at least 0.15 m. Distances from wires to walls and supporting structures must be at least 50 mm.

2.1.78. The laying of wires and cables for external electrical wiring in pipes, ducts and flexible metal sleeves must be carried out in accordance with the requirements given in 2.1.63-2.1.65, and in all cases with a seal. Laying wires in steel pipes and ducts in the ground outside buildings is not allowed.

The distance from the wires in front of the input and the input wires to the ground surface must be at least 2.75 m (see also 2.4.37 and 2.4.56).

The distance between the wires at the input insulators, as well as from the wires to the protruding parts of the building (roof overhangs, etc.) must be at least 0.2 m.

Entries may be made through roofs in steel pipes. In this case, the vertical distance from the branch wires to the input and from the input wires to the roof must be at least 2.5 m.

For buildings of small height ( shopping pavilions, kiosks, container-type buildings, mobile booths, vans, etc.), on the roofs of which people are excluded, the clear distance from the branch wires to the input and the input wires to the roof is allowed to be at least 0.5 m. In this case, the distance from the wires to the ground surface there must be at least 2.75 m.

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Electrical wiring | energy drink

Electrical wiring and cable lines

Electrical installations different organizations, isolated in administrative and economic terms, located in the same building, can be connected by branches to a common supply line or fed by separate lines from the ASU or main switchboard.
It is allowed to connect several risers to one line. On branches to each riser supplying apartments residential buildings with more than 5 floors, a control device combined with a protection device should be installed.
Lamps in residential buildings stairwells, lobbies, halls, floor corridors and other indoor premises outside apartments must be powered via independent lines from the ASU or separate group panels powered from the ASU. Connecting these lamps to floor and apartment panels not allowed.
For staircases and corridors with daylight, it is recommended to provide automatic control electric lighting depending on the illumination created by natural light.
It is recommended to supply electrical installations of non-residential buildings with separate lines.

7.1.34. In buildings, cables and wires with copper conductors* should be used.

Supply and distribution networks, as a rule, must be made of cables and wires with aluminum conductors if their design cross-section is 16 mm2 or more.

The power supply of individual electrical receivers related to the engineering equipment of buildings (pumps, fans, heaters, air conditioning units, etc.) can be provided by wires or cables with aluminum conductors with a cross-section of at least 2.5 mm2.

In museums, art galleries, and exhibition spaces, it is permitted to use lighting busbar trunking systems with a degree of protection IP20, in which the branch devices to the lamps have detachable contact connections located inside the busbar trunking box at the time of switching, and busbar trunking systems with a degree of protection IP44, in which the branching devices to the lamps are made with using plug connectors that ensure the branch circuit is broken until the plug is removed from the socket.

In residential buildings, the cross-sections of copper conductors must correspond to the calculated values, but not be less than those indicated in Table 7.1.1.

*Until 2001, according to the existing construction backlog, the use of wires and cables with aluminum conductors was allowed.

Flame retardant gasket is allowed in common pipe, a common box or channel of building structures made of non-combustible materials, wires and cables of supply lines of apartments together with wires and cables of group lines of working lighting of staircases, floor corridors and other indoor premises.

Table 7.1.1. The smallest permissible cross-sections of cables and wires of electrical networks in residential buildings

Conductor cross-sections must meet the requirements of clause 7.1.45.

7.1.38. Electricity of the net, laid behind impenetrable suspended ceilings and in partitions, are considered as hidden electrical wiring and should be installed: behind ceilings and in the voids of partitions made of flammable materials in metal pipes ah, with localization ability, and in closed boxes; behind ceilings and in partitions made of non-combustible materials* - in pipes and ducts made of non-flammable materials, as well as flame retardant cables. In this case, it must be possible to replace wires and cables.

*Under suspended ceilings made of non-combustible materials we mean those ceilings that are made of non-combustible materials, while others building construction, located above suspended ceilings, including interfloor ceilings, are also made of non-combustible materials.

In saunas for zones 3 and 4 according to GOST R 50571.12-96 “Electrical installations of buildings. Part 7. Requirements for special electrical installations. Section 703: Premises Containing Sauna Heaters" electrical wiring with an insulation temperature rating of 170°C must be used.

7.1.41. Electrical wiring in attics must be carried out in accordance with the requirements of Section. 2.

Three-phase four- and five-wire lines when supplying three-phase symmetrical loads must have a cross-section of zero working (N) conductors equal to the cross-section of phase conductors, if the phase conductors have a cross-section of up to 16 mm2 for copper and 25 mm2 for aluminum, and for large cross-sections - at least 50 % cross-section of phase conductors.

The cross-section of PEN conductors must be at least the cross-section of N conductors and at least 10 mm2 for copper and 16 mm2 for aluminum, regardless of the cross-section of the phase conductors.

The cross-section of PE conductors must be equal to the cross-section of phase conductors with a cross-section of the latter up to 16 mm2, 16 mm2 with a cross-section of phase conductors from 16 to 35 mm2 and 50% of the cross-section of phase conductors with larger cross-sections.

The cross-section of PE conductors not included in the cable must be at least 2.5 mm2 - if available mechanical protection and 4 mm2 - in its absence.

Return to section ⇒ Electrical wiring

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PUE: Electrical wiring and cable lines

Electrical wiring and cable lines

7.1.32. Internal wiring must be carried out taking into account the following:

1. Electrical installations of different organizations, separate administratively and economically, located in the same building, can be connected by branches to a common supply line or fed by separate lines from the ASU or main switchboard.

2. It is allowed to connect several risers to one line. On branches to each riser supplying apartments in residential buildings with more than 5 floors, a control device combined with a protection device should be installed.

3. In residential buildings, lamps in staircases, lobbies, halls, floor corridors and other indoor premises outside apartments must be powered via independent lines from the ASU or separate group panels powered from the ASU. Connecting these lamps to floor and apartment panels is not allowed.

4. For staircases and corridors with natural light, it is recommended to provide automatic control of electric lighting depending on the illumination created by natural light.

5. It is recommended to supply power to electrical installations of non-residential buildings using separate lines.

7.1.33. Supply networks from substations to VU, ASU, main switchboard must be protected from short-circuit currents.

7.1.34. In buildings, cables and wires with copper conductors should be used 1

Supply and distribution networks, as a rule, must be made of cables and wires with aluminum conductors if their design cross-section is 16 mm 2 or more.

Power supply to individual electrical receivers related to the engineering equipment of buildings (pumps, fans, heaters, air conditioning units, etc.) can be carried out by wires or cables with aluminum conductors with a cross-section of at least 2.5 mm 2.

In the specified premises, lighting busbars must be powered from distribution points independent lines.

In residential buildings, the cross-sections of copper conductors must correspond to the calculated values, but not be less than those indicated in table 7.1.1.

1 Until 2001, according to the existing construction backlog, the use of wires and cables with aluminum conductors was allowed.

The smallest permissible cross-sections of cables and wires of electrical networks in residential buildings.

7.1.35. In residential buildings, laying vertical sections of the distribution network inside apartments is not allowed.

It is prohibited to lay wires and cables supplying lines from the floor panel in a common pipe, common box or channel different apartments.

Fire-retardant installation in a common pipe, common box or channel of building structures made of non-combustible materials, wires and cables of apartment supply lines together with wires and cables of group lines of working lighting of staircases, floor-by-floor corridors and other indoor premises is allowed.

7.1.36. In all buildings, group network lines laid from group, floor and apartment panels to general lighting fixtures, plug sockets and stationary electrical receivers must be three-wire (phase - L, zero working - N and zero protective - PE conductors).

Combining zero working and zero protective conductors of different group lines is not allowed.

The neutral working and neutral protective conductors are not allowed to be connected on panels under a common contact terminal.

Conductor cross-sections must meet the requirements of clause 7.1.45.

7.1.37. Electrical wiring in the premises should be replaced: hidden - in the channels of building structures, embedded pipes; open - in electrical skirting boards, boxes, etc.

In technical floors, undergrounds, unheated basements, attics, ventilation chambers, damp and especially damp rooms, it is recommended that electrical wiring be carried out openly.

In buildings with building structures made of non-combustible materials, permanent, monolithic installation of group networks is allowed in the grooves of walls, partitions, ceilings, under plaster, in the floor preparation layer or in the voids of building structures, carried out with cable or insulated wires in a protective sheath. The use of permanently embedded wiring in panels of walls, partitions and ceilings, made during their manufacture at construction industry factories or carried out in the mounting joints of panels during the installation of buildings, is not allowed.

7.1.38. Electrical networks laid behind impenetrable suspended ceilings and in partitions are considered as hidden electrical wiring and should be installed: behind ceilings and in the voids of partitions made of flammable materials in metal pipes with localization capabilities and in closed boxes; behind ceilings and in partitions made of non-combustible materials 2 - in pipes and ducts made of non-flammable materials, as well as flame retardant cables. In this case, it must be possible to replace wires and cables.

2 Suspended ceilings made of non-combustible materials mean those ceilings that are made of non-combustible materials, while other building structures located above suspended ceilings, including interfloor ceilings, are also made of non-combustible materials.

7.1.39. In rooms for cooking and eating, with the exception of apartment kitchens, open laying of cables is allowed. Open gasket wires are not allowed in these rooms.

In apartment kitchens, the same types of electrical wiring can be used as in living rooms and corridors.

7.1.40. In saunas, bathrooms, toilets, showers, as a rule, hidden electrical wiring should be used. Open cable routing is allowed.

In saunas, bathrooms, toilets, showers, laying wires with metal sheaths, in metal pipes and metal sleeves is not allowed.

In saunas for zones 3 and 4 according to GOST R 50571.12-96 "Electrical installations of buildings. Part 7. Requirements for special electrical installations. Section 703. Premises containing sauna heaters" electrical wiring with a permissible insulation temperature of 170 o c must be used.

7.1.41. Electrical wiring in attics must be carried out in accordance with the requirements of Section. 2.

7.1.42. Through the basements and technical underground sections of the building, it is allowed to lay power cables with a voltage of up to 1 kV, powering electrical receivers of other sections of the building. The specified cables are not considered as transit; laying transit cables through basements and technical undergrounds of buildings is prohibited.

7.1.43. Open laying of transit cables and wires through storerooms and warehouses is not permitted.

7.1.44. Lines feeding refrigeration units trade enterprises and Catering, must be laid from the ASU or main switchboard of these enterprises.

7.1.45. The selection of conductor cross-sections should be carried out in accordance with the requirements of the relevant chapters of the PUE.

Single-phase two- and three-wire lines, as well as three-phase four- and five-wire lines when supplying single-phase loads, must have a cross-section of zero working (N) conductors equal to the cross-section of phase conductors.

Three-phase four- and five-wire lines when feeding three-phase symmetrical loads must have a cross-section of zero working (N) conductors equal to the cross-section of phase conductors, if the phase conductors have a cross-section of up to 16 mm 2 for copper and 25 mm 2 for aluminum, and for large cross-sections - not less than 50% of the cross-section of phase conductors.

The cross-section of PEN conductors must be at least the cross-section of N conductors and at least 10 mm 2 for copper and 16 mm 2 for aluminum, regardless of the cross-section of the phase conductors.

The cross-section of PE conductors must be equal to the cross-section of phase conductors with a cross-section of the latter up to 16 mm 2. 16 mm 2 with a cross-section of phase conductors from 16 to 35 mm 2 and 50% of the cross-section of phase conductors with larger cross-sections.

The cross-section of PE conductors not included in the cable must be at least 2.5 mm 2 - if there is mechanical protection and 4 mm 2 - if there is none.

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Don't forget about something new:
Federal Law of July 22, 2008 N 123-FZ
"Technical regulations on requirements fire safety"
Article 82. Fire safety requirements for electrical installations of buildings, structures and structures
1. Electrical installations of buildings, structures and structures must comply with the class of the fire and explosion hazardous zone in which they are installed, as well as the category and group of the combustible mixture.
2. Cables and wires of fire protection systems, means of supporting the activities of fire departments, fire detection systems, warning and management of evacuation of people in case of fire, emergency lighting on evacuation routes, emergency ventilation and smoke protection, automatic fire extinguishing, internal fire-fighting water supply, elevators for transporting fire departments in buildings, structures and structures must remain operational in fire conditions for the time necessary for the complete evacuation of people to a safe area.
3. Cables from transformer substations backup power supplies to input distribution devices must be laid in separate fire-resistant channels or have fire protection.
4. Power supply lines to premises of buildings, structures and structures must have protective shutdown devices that prevent a fire from occurring in the event of a malfunction of electrical receivers. The installation rules and parameters of residual current devices must take into account the fire safety requirements established in accordance with this Federal Law.
5. Distribution boards must have a design that prevents the spread of combustion beyond the board from the low-current compartment to the power compartment and vice versa.
6. The distribution of cables and wires from floor distribution panels to premises must be carried out in channels made of non-combustible building structures or molded fittings that meet fire safety requirements.
7. Horizontal and vertical channels for laying electrical cables and wires in buildings, structures and structures must be protected from the spread of fire. In places where cable channels, ducts, cables and wires pass through building structures with a rated fire resistance limit, cable penetrations with a fire resistance limit not lower than the fire resistance limit of these structures must be provided.
8. Cables laid openly must be flame retardant.
9. Emergency lighting fixtures on escape routes with autonomous power sources must be provided with devices to test their functionality when simulating a shutdown of the main power source. The operating resource of the autonomous power source must provide emergency lighting on evacuation routes during the estimated time of evacuation of people to a safe zone.
10. Electrical equipment without fire and explosion protection means is not allowed to be used in explosive, explosive and fire hazardous areas of buildings, structures and structures that do not have additional protective measures aimed at eliminating the danger of an ignition source in a flammable environment.
11. Fire-proof electrical equipment is not allowed to be used in explosive and fire-hazardous areas.
12. Explosion-proof electrical equipment may be used in fire-hazardous and non-fire-hazardous premises, and in explosive premises - provided that the category and group of the explosive mixture in the room corresponds to the type of explosion protection of the electrical equipment.
13. Rules for the use of electrical equipment depending on the degree of its explosion and fire resistance fire danger in buildings, structures and structures for various purposes, as well as fire hazard indicators of electrical equipment and methods for their determination are established by federal laws on technical regulations for this product and/or regulatory documents on fire safety.

When laying any communications, cable penetrations must be constructed - products, prefabricated structures that are designed for the passage of cables, pipelines, communication lines through walls and partitions. Their main purpose is to prevent fire from spreading into adjacent rooms through flammable materials. They are arranged on the basis of SP 2.13130.2009 and GOST R 53310-2009. Their installation is mandatory and regulated by Federal Laws.

Fire compartments and cable penetrations

According to the requirements, during the construction of residential buildings, they are divided into fire compartments, which block fire and smoke on their territory and prevent them from spreading beyond the boundaries of the compartment. However, utility lines pass through any room, which violate the integrity and tightness of the fire section. In order to maintain the fire resistance limits of the structure and penetration.

A striking example that proves the need to install such structures is the fire at the Ostankino TV tower in 2000. Here, telecommunication lines were placed in a vertical shaft, without dividing it into fire compartments and laying protective passages. As a result, the fire quickly spread throughout the building.

Design of cable penetrations

The simplest cable penetration is a metal sleeve embedded in a wall or partition. A cable or pipeline passes through the sleeve, the outer diameter of which is slightly smaller than the diameter of the fire protection structure. The gap between the communication line and the inner wall of the sleeve is filled with tow, thoroughly soaked in fat. That is why the simplest cable penetrations are also called glands. Also, along with or instead of tow, asbestos, rubberized rings, and special packings can be used.

At industrial facilities and power plants, slightly different structures are installed. They are two ends of which are connected by sleeves. To seal the gap between communications and internal walls, special diaphragms and washers are used. One such cable penetration is used to pass several utility lines.

Sealing materials

To create the possibility of laying an additional or replacing an old utility line, all other communications pass through the walls in boxes or pieces of metal pipes (sleeves). Therefore, the sealing of cable penetrations must be made of fire-resistant, water- and gas-tight material that is easy to remove.

In this case, the ability of the embedding to resist fire should be no lower than the fire-resistant ability of the wall.

SNiP 3.05.06-85 specifies specific mixtures that can be used to fill the gap between the cable and the penetration:

cement-sand mixture in a ratio of 1:10;
composition of clay and sand with a material ratio of 1:3;
sealing mass of clay, sand and cement (1.5:11:1);
gypsum and taken in a ratio of 2:1;
other materials that meet fire safety requirements.

Cable penetrations are also allowed to be sealed construction foam, if it is certified in accordance with the requirements of GOST R 53310-2009. Gaps in the walls do not need to be filled if the partitions are not fire barriers.

Modular penetrations

IN modern construction Modular penetrations are used to isolate fire compartments. They are steel or plastic frames, which are equipped with blind inserts or modules with holes. To protect against electromagnetic radiation, copper gaskets are installed. The tightness is created by tension bolts.

IN general view modular cable penetrations for fire protection are complex design, assembled on site from prefabricated sealing inserts made of a polymer that is difficult to burn. Elements made of galvanized high-grade steel are used as fastenings.

In this penetration, the cable is placed in a special sealing module and crimped with an adapter for increased tightness. When the tension bolts are screwed in, the sealing inserts are compressed, tightly compressing the cable and ensuring gas- and water-tightness of the penetration.

Features of installation of cable penetrations

Installation of penetrations has its own characteristics, which depend on the type of material load-bearing structure. So, laying cable systems in monolithic concrete buildings, fire protection structures are laid directly into the formwork before pouring concrete mixture. When constructing prefabricated monolithic buildings, penetrations are laid into blocks at the factory during their manufacture.

In brick houses, for installation, cable systems are placed in special channels - grooves. In finished monolithic buildings, small holes are drilled with a diamond drill. The diameter of the penetration is calculated separately. During construction or temporary operation of a building, penetrations are made of special fireproof cushions.

Cable Penetration Testing

Depending on the location of operation, cable penetrations must meet established requirements. Thus, when they are installed at nuclear power plants, they must be tested for their ability to absorb, insulate or reflect radiation.

At ordinary construction sites, universal cable penetrations are tested by heating, force (mainly on bending resistance), as well as fire resistance, water and gas insulation properties.

Cable penetrations through walls and ceilings. Places where cables pass through ceilings, walls, fire-resistant partitions in cable tunnels must be carefully sealed with non-combustible material, and sealing is also carried out around the cables passing through the nozzles. This is one of the necessary measures to prevent the spread of fires in cable networks and water penetration into the building through pipes.

Normalized distances. The PUE defines the smallest permissible distances between the cable being laid and other cables, building foundations, green spaces, pipelines with flammable liquid, heating pipelines, communication cables, electrified and non-electrified railways, tram rails, both when located parallel to them and when crossing them. The PUE also provides for protection measures when approaching these devices.

These restrictions are established in order to create normal conditions for the operation of cables and minimize the harmful effects of all kinds of devices on the cable. If we're talking about about pipelines, then the minimum permissible approach during parallel laying of 1 m is necessary to ensure that the cable is not damaged during excavations associated with pipeline repairs. For a heat pipe, the specified proximity is 2 m in order to minimize the harmful influence of the heat generated by the heat pipe on the cooling conditions of the cable. Tram, electrified railways, subway lines are a source of propagation in the ground stray currents, which, in the absence of proper protection, have a destructive effect on the armor and metal sheath of the cable. Therefore, the permissible approach to such structures is already 10 m or, if this distance needs to be reduced, the cables are laid in insulating pipes (for example, asbestos-cement, impregnated with tar or bitumen). Thus, each restriction on approaches and intersections has its own justification and must be observed when laying cables.

Industrial preparation of cables. IN Lately developed and implemented in a number of installation organizations method of preliminary preparation in workshops of measured sections of armored cables. On a mechanized technological line, the cable is rewinded from the factory drum to a special inventory drum with measuring required length on the cable meter; cable cutting and installation of terminations and couplings. Prepared sections of cables are tested with increased voltage, the cable cores are marked and colored, and the cable in an inventory drum is delivered to the site for laying on a prepared route.

The main element of the production line is an inventory cable drum with an electric drive, as well as a counting device, with the help of which the process of measuring and rewinding cables is mechanized. The inventory drum consists of a welded frame, inside of which a rotating drum is placed. On the side cheeks of the rotating drum there are structures for fastening couplings and end seals. The electric drive is connected to the drum by a hinge shaft. A measuring device with a counter, type SK-1, consists of a frame and a movable stand. The frame is equipped with guide rollers and a copper disk connected to a cable meter. The measuring disk, moving transversely on the guide pins, ensures that the cable is laid turn to turn. The drum with cable is lifted using a cable jack. Other installation operations are also mechanized at the stand: rounding of sector cores, crimping of tips and sleeves (PGEP press), welding and soldering with propane-butane torches, cable cutting with a stationary cable knife With manual drive, marking plastic tags special device and etc.

Industrial cable preparation reduces cable waste and labor costs in general, reduces installation time and improves installation quality cable joints and sealing.