RU139056U1 - ELECTRIC FIRE RESISTANT CABLE, PREVIOUSLY EXPLOSION-FIRE-SAFE, NON-DISTRIBUTIVE COMBUSTION, FOR EXTREMELY SAFE CHAINS - Google Patents

Abstract

1. An electrical fire-resistant cable, mainly explosion and fireproof, flame retardant, including for intrinsically safe circuits, containing a core consisting of at least one insulated single-wire or multi-wire conductive copper or copper tinned core, or at least one group of these cores, twisted into a pair or three, or four, and a moisture-proof sheath, characterized in that the insulation of the said conductive conductors is made of a two-layer combined, the first layer adjacent to the said conductive core is extruded from silicone rubber, ceramizing under flame conditions, the second layer is made of not less than one mica tape imposed by a winding in a spiral with overlapping mica coating inside, with the tape being tensioned during winding of at least 7 N, for identification over the winding An individual number is printed with contrasting ink or paint on each insulated core with a mica tape, and a bandage of at least one mica linen is applied over the core th winding helically overlapping vnutr.2 coated mica. A cable according to claim 1, characterized in that when there are more than one isolated cores or groups in the core, the cores or groups are twisted together into a core. 3. Cable according to any one of paragraphs. 1 or 2, characterized in that under the said insulation an additional layer of at least one mica tape is applied by winding in a spiral with overlapping mica coating inward. 4. Cable according to any one of paragraphs. 1 or 2, characterized in that on top of the named insulated core is additionally superimposed

Description

The field of technology.

The utility model relates to cable technology, namely: to designs of multicore electric cables, operable for a limited time under fire conditions under the direct influence of a flame, flame retardant, designed for fixed inter-instrument installation of electrical devices of industrial enterprises, including in explosive zones of all classes when using various explosion protection methods, including “intrinsically safe electrical circuit i” according to GOST Ρ 51330-10-99, GOST Ρ 51330-13-99, GOST Ρ 52350-14-2005, GOS T Ρ IEC 60079-11-2010, GOST IEC 60079-14-2011.

The achieved level of technology.

Fire-resistant cables are those that maintain working capacity (withstand operating voltage or ensure the transmission of electromagnetic signals) under direct exposure to a flame. According to GOST Ρ 53315-2009 “Cable products. Fire safety requirements. Test methods ”, fire-resistant cables are designed for single and group laying (taking into account the volume of combustible loading) of power circuits for electrical receivers of fire protection systems, fire alarm systems, fire warning systems, operating and resuscitation-anesthetic equipment of hospitals and hospitals, as well as other electrical receivers which must remain operational in a fire.

A number of fire-resistant designs of various types of electric cables were developed according to the patents for utility models RU No. 277732, RU No. 566059, RU No. 70405, RU No. 125386 and others, characterized in that the fire-resistant insulation of the conductive core was carried out by a two-layer combined. The first layer consisted of at least one mica tape, imposed by a spiral winding with overlapping. The second layer was extruded polymer, the specific type of polymer was selected based on additional requirements, for example, according to the volume of halogen-containing corrosive acids released during a fire.

Under the influence of a flame, the polymer coating burns out, but the mica tape winding retains dielectric properties at a temperature of at least 750 ° C (minimum test temperature in accordance with GOST IEC 60331-21-2011) and withstands the fire test when applied to conductive conductors of up to 1 voltage , 0 kV, which is defined as maintaining operability. However, this test is idealized and does not take into account the effect of fire extinguishing agents on the test object.

The disadvantage of these utility models is that when extinguishing a fire, water can leak through the leakage of the aforementioned winding, as a result of which electrical breakdown between conductive cores can occur, which is a failure to maintain the cable’s operability.

In addition, another series of fire-resistant designs of electric cables of various types was developed according to patents for utility models RU No. 44484, RU No. 67294, RU No. 90254, RU No. 124977 and others, as well as patents for inventions RU No. 22989869, RU No. 2285306, RU No. 2370839, characterized in that the flame-retardant core is made of insulation of ceramicizable silicone rubber or rubber based on a mixture of rubbers using methylsiloxane rubber, applied by extrusion, followed by cross-linking.

Under the influence of a flame in these cables ceramicization of organosilicon insulation occurs. The ceramic layer formed on the conductive core has a slightly smaller thickness compared to the initial insulation, withstands electrical voltage up to 1.0 kV when exposed to direct flame with a temperature of at least 750 ° C, and therefore also ensures operability according to GOST IEC 60331 -21-2011. Moreover, with a certain thickness of the resulting ceramics, the insulation can withstand the applied voltage when water is used to extinguish the fire.

However, when extinguishing a fire, in addition to water, mechanical shocks are possible. The cables are checked for operability when exposed to a flame with a temperature of not less than 830 ° C simultaneously with mechanical shock according to GOST 60 IEC 60331-31-2007 “Testing of electrical cables under conditions of flame exposure. Saving performance. Part 31. Conducting tests and requirements for them when exposed to flame simultaneously with mechanical shock. Cables for rated voltage up to and including 0.6 / 1.0 kV. ”

The disadvantage of fire-resistant cables with ceramicizable silicone insulation is that ceramics formed under the influence of a flame have insufficient mechanical strength and can not withstand mechanical shocks that occur during a fire.

A number of patents for utility models, such as RU No. 53807, RU No. 63111, RU No. 91463, RU No. 96692, RU No. 96693, use both of the above embodiments of the fire-resistant core with the same disadvantages.

Patents for utility models RU No. 47131, RU No. 57958 are also known, in which fire resistance is ensured by the application of one or two mica tapes, each winding additionally containing a layer of organosilicon material in the form of a non-drying paste, in general, a sealing composition. However, this solution does not give a positive result in case of fire, since the sealing compound is not ceramicizable, it burns out under the influence of fire and gives water access to conductive veins.

Known high-frequency fire-resistant coaxial cable according to the invention patent RU No. 2449395, IPC: H01B 11/18.

The cable consists of an internal conductor with four sequentially applied layers of insulation: thin-walled, enlarged, mica and external. An outer conductor with a sheath is laid over the outer layer of insulation. In this case, the thin-walled insulation layer is made of raw calendered polytetrafluoroethylene tapes, the increased insulation layer is made of porous polytetrafluoroethylene tapes, mica insulation - from mica tape, the outer insulation layer is made of polytetrafluoroethylene or its copolymers by compression extrusion.

The disadvantage of this design is that with a long exposure of the cable in a flame (from 30 to 180 minutes, as required by GOST 33 53315-2009), the PTFE insulation layers will burn out, the winding of mica tape, which does not have a solid base, under dynamic influence the flame is deformed, as a result of which the mica coating will crack and the conductive core will be exposed, which will lead to electrical breakdown. Thus, the cable will not provide the requirement of operability under the direct influence of the flame during exposure from 30 to 180 minutes.

In the utility model RU No. 91463, a two-layer combined insulation option is also provided. In it, the first layer is made in the form of a winding with an overlap of at least one mica tape, and the second is extruded from ceramicizable silicone rubber.

This design also has drawbacks: under the influence of mechanical shocks, the ceramics formed in the flame will be destroyed, and water falling into the place of crumbled ceramics will penetrate between the winding layers of mica belts and a short circuit will occur between the conductive conductors.

The closest we can consider the cable design according to the patent for utility model RU No. 49340 dated 08.02.2005, IPC: H01B 7/02. It describes a fire-resistant flexible electric cable, including one or several multi-wire flexible conductive conductors with flame-retardant insulation made of organosilicon rubber, a two-layer fastening element made in the form of a winding of glass mica tape for each conductive core and of glass tape over the insulation of each core with overlapping, and a sheath of PVC compound or low fire hazard rubber.

According to the description, the objective of this utility model is to create such a design of a flexible fire-resistant cable in which the dependence of fire resistance on operational mechanical stresses (bends, vibration, shock, mechanical load) would be eliminated.

In this design, silicone rubber when burned by flame temperature (from 600 to 900 ° C) burns with the formation of a layer of silicon dioxide, which is a dielectric and prevents immediate electrical breakdown of insulation. The volume of the resulting silicon dioxide is much less than the volume occupied by the starting material - silicone rubber. In addition, silicon dioxide is obtained in the form of a brittle material. And although silicon dioxide is localized within a space limited by a glass tape winding, it is destroyed under the influence of mechanical shocks, and under the influence of gravity it can be redistributed within this space and, depending on the spatial location of the cable, the conductive core will be exposed. Since the glass tape is not protected by a layer of mica (in the most general form, as indicated in the patent description), under the influence of a flame, it sharply loses its strength properties and cracks, water entering the cable during fire extinguishing penetrates the glass tape winding and a short circuit occurs between conductive conductors . The specified disadvantage does not allow guaranteed use of such a design in conditions of the possibility of a fire with subsequent fire fighting with water.

As a prototype, we choose the design of the fire-resistant cable according to the patent for utility model RU No. 49340.

The essence of the utility model.

The essence of the proposed utility model is to create an electrical fire-resistant cable, mainly explosion-proof, flame retardant, including for intrinsically safe circuits, operable during a fire with mechanical shock on the base of the cable fastener, after being filled with water.

The technical result.

The technical result is achieved by the fact that the proposed electrical fireproof cable, mainly explosion and fireproof, flame retardant, including for intrinsically safe circuits, containing a core consisting of at least one insulated single-wire or multi-wire conductive copper or copper tinned core, or at least one groups of the named conductors twisted in a pair or three, or four, and a moisture-proof sheath, insulation of the named conductive conductors is made of a two-layer combined Anna, the first layer adjacent to the named conductive core is extruded from silicone rubber, ceramizing under flame conditions, the second layer is made of at least one mica tape wrapped in a spiral winding with a mica coating inward, with the tape being tensioned for at least 7 H, for the purpose of identification on top of the winding with mica tape, an individual number is printed on each named insulated core with contrasting ink or paint, and no bandage is applied over the core enee slyudinitovoy than one winding tape helically lapped mica coated inside.

Fire extinguishing of explosive objects, as well as significant cooling of explosive objects standing next to a burning one, is in some cases carried out by compact water jets from hand and fire monitors under pressure from pumps and pumping stations. To simulate this case, water should be poured onto the cable.

To confirm the operability of the explosion-proof cable in a fire when using fire extinguishing means, we will choose the most widely used international standard IEC 60331-31-1999 in the world, which has the authentic Russian document GOST Ρ IEC 60331-31-2007. In this test, a cable under operating voltage is simultaneously exposed to a flame with a temperature of at least 830 ° C and mechanical shocks to the base of the cable mount with a frequency of 1 shock every five minutes.

The exposure time should be equal to 180 minutes, the maximum value regulated by GOST Ρ 53315-2009. After the required time has passed, the burner is turned off, the blows cease, and 5 liters are poured slowly (in many tricks) onto the middle part of the cable 400 mm long (which has been on fire). water.

This technique imitates the real case when a burning liquid (from the category of flammable liquids) enters the cable channel, where a fire-resistant cable is laid, and then water displaces it. The volume of water is 5 l. is selected based on the condition of covering the medium size cable with water in the cable channel.

Both insulation layers provide fire resistance in accordance with GOST IEC 60331-21-2011 without additional influences, as evidenced by repeated tests throughout the world. But the partial burning out of a layer of siliconizing silicone rubber leads to some freedom of the conductive core in ceramic insulation inside the mica winding, which becomes stiff under the influence of a flame. Mechanical impacts on the base lead to shaking of the cable and the beating of the conductive core in ceramic insulation inside the mica winding, which can lead to the destruction of the ceramic insulation. In order to eliminate this phenomenon, in the manufacture of the cable, the winding is applied with a tension of at least 7 H, which leads to an additional compaction of the ceramicizable silicone insulation and, when part of the insulation burns out under the influence of a flame, it ensures continuity of compression of the ceramic insulation with a micaceous winding during flame exposure and increases resistance to mechanical shocks (impacts on the basis of the mount).

As a rule, fire fighting water is used with a temperature corresponding to normal climatic conditions (20 ± 15) ° C. The possibility of its heating in the process of extinguishing a fire is neglected. The ingress of water with such a temperature onto a hot insulation surface of conductive conductors with a temperature of at least 830 ° C leads to an explosive nature of the occurrence of physical processes with the possibility of mechanical damage to the insulation. In order to avoid mechanical damage to the insulation, it is advisable to apply a winding of at least one mica tape with overlap on the core. In this case, the core winding will take the main blow, and the water penetrating into the core will have a temperature close to the evaporation temperature and will not lead to significant mechanical damage to the insulation.

Ensuring fire resistance properties is also a confirmation of explosion and fire safety, since the absence of electrical breakdown at operating voltage means the absence of sparks that can ignite an explosive gas, the presence of which is characteristic of explosive zones.

The property of the cable, defined as non-proliferation of combustion, is provided by the “oxygen index” indicator. To ensure the most stringent requirement of “non-proliferation during group laying”, the polymeric materials included in the structure must have an oxygen index of at least 28. Since mica tapes and ceramicizable silicone rubber are non-flame retardant materials, and the rest of the polymeric materials of the structure have an oxygen index of at least 28, then the cable as a whole is flame retardant for group installation.

Compliance with the standards for intrinsically safe circuits is determined by the thickness of the insulation, regardless of its chemical composition. With the right choice of thickness and operating voltage (according to GOST Ρ IEC 60079-11-2011 table 5), fire-resistant cable will be applicable for intrinsically safe circuits.

The technical result consists in ensuring the operability of the proposed cable during a fire with a temperature of at least 830 ° C with mechanical shock to the base of the cable fastening with a frequency of one hit every five minutes for 180 minutes, followed by gradual pouring onto the middle part of the cable 400 mm long on fire, water in a volume of 5 liters.

In order to identify isolated conductive wires on top of the mica tape, an individual number is applied to each insulated core with contrasting ink or paint.

To ensure compactness of the core with the number of cores or groups of more than one, it is advisable to twist them together into a core.

In order to provide additional protection against possible mechanical shocks during the fire and squeeze the insulation, it is advisable to additionally apply a layer of at least one mica tape by spiral winding with the mica coating inward under the mentioned insulation.

In order to protect against tearing during rewinding during technological operations, it is advisable to add a protective polymer tape over the spiral insulated core over the aforementioned insulated core, on top of which the individual number of the insulated core is applied with contrasting ink or paint.

For the case of the location of technological equipment in a humid atmosphere, it is advisable to additionally lay an extruded layer of silicone rubber over the aforementioned insulated core, which ceramics under the influence of a flame, on top of which apply the individual number of the insulated core with contrasting ink or paint.

In the case of installation of the cable in conditions of poor visibility, the extruded silicone rubber layer, which is additionally applied over an insulated core, it is advisable to individually paint in the mass during extrusion, providing an individual color sufficient to ensure that these groups are distinguished in the core, the cores in the group and in the core, twisted from single veins.

Based on the requirement of noise immunity, it is advisable to establish coordinated steps for adjacent groups (unequal and non-multiple) when twisting, as well as to limit the pitch of twisting the wires in groups as follows: in a group of two wires (in a pair) - no more than 0.1 m, out of three - not more than 0.15 m, of four cores - not more than 0.2 m.

In order to protect against electromagnetic effects, it is advisable to run a cable with at least one screen. At the same time, to protect against internal electromagnetic influences and to organize grounding circuits according to screens, it is advisable to make screens individual, superimposed on a separate conductive core or group, superimposed on a separate group. To protect against external electromagnetic influences, it is advisable to make the screen common, superimposed on the core or over the brace.

Advantageously, for intrinsically safe cables, it is advisable to extrude each individual or group screen with a polymer sheath or belt insulation in the form of a spiral winding with at least one polymer tape overlapping, and the thickness of the polymer sheath and belt insulation according to individual and group screens should be chosen so that it withstood a test of at least 500 V AC at a frequency of 50 Hz, applied between any individual or group, or common screens, which meets the requirements of Clause 12.2.2.1 of GOST Ρ 51330-13-99 and Clause 12.2.2.1 of GOST IEC 60079-14-2011.

To protect against electromagnetic effects in the low frequency range, it is advisable to make a screen in the form of a braid or winding from tinned copper or copper wires.

To protect against electromagnetic effects in the range of high and medium frequencies, it is advisable to produce a screen of at least one metal-polymer tape imposed by the metal inward with a spiral winding overlapping or longitudinally with the screen wire laid under the screen.

To protect against electromagnetic effects in a wide range of frequencies, it is advisable to make a screen in the form of a braid or winding from tinned copper or copper tinned wires, additionally laying under the braid or winding with metal upwards overlapping the metal-polymer tape longitudinally or by winding in a spiral.

In accordance with Article 82 of the Federal Law of the Russian Federation of 07.22.08. No. 123-F3 “Technical regulation on fire safety requirements” in industrial premises with open installation, non-propagating cables should be used. In this regard, under the condition of group laying, the materials for the shells, filler, moisture barrier should be selected from the following series: special polyvinyl chloride plastic compound with an oxygen index of at least 35 with low smoke and gas emission or a halogen-free polymer composition with an oxygen index of at least 35, or a polyolefin thermoplastic elastomer with oxygen index of at least 29, or a polyurethane thermoplastic elastomer with an oxygen index of at least 29, or silicone rubber with an oxygen index of at least 29, while including keramiziruyuschayasya under fire conditions (for oxygen index filler should be at least 28 by using any material, as it contains large amounts of mineral filler).

To ensure a round cable shape over the core, it is advisable to apply a polymer aggregate with an extruded concentric layer.

For cables laid from the explosive zone to the non-explosive one in order to ensure longitudinal sealing, it is advisable to introduce an additional filler into the air cavities of the core and the above groups.

To facilitate the design of the cable and reduce material consumption, it is advisable to place the filler from foam material.

To ensure the complex of the claimed properties of the cable, the filler is advisable to perform on the basis of a material homogeneous with the material of the shells.

For the purpose of identification during operation, it is advisable to paint the cable sheath for intrinsically safe circuits in blue or separately impose a blue strip on the main color.

According to the EMP (Electrical Installation Rules), only armored cables are laid openly and unlimitedly in hazardous areas: they do not require additional protection or any simplified lightweight conditions, therefore they are widely used.

When using cables under the influence of radial (crushing) forces, it is advisable to apply armor from steel wires under a moisture protective sheath by winding in a spiral or in the form of a braid.

When using cables under the influence of longitudinal (tensile) forces, it is advisable to apply armor from steel tapes under a moisture protective sheath by winding in a spiral or longitudinally from a pre-corrugated steel tape laminated with polymer.

In order to prevent the longitudinal distribution of water under the armor in case of violation of the integrity of the moisture barrier during operation in a humid environment, it is advisable to additionally lay a layer of water blocking material under the armor.

To improve the technology and prevent possible destruction of the aggregate at the time of applying the armor, it is advisable to extrude an intermediate shell made of a polymer material homogeneous with the material called a moisture-proof shell or winding with at least one polymer tape with overlap under the armor. The choice between the intermediate shell and the winding is based on the degree of destructive effect of the armor during application and for economic reasons.

Description of the drawings.

The proposed utility model is illustrated by a specific example of execution, represented by a cross-sectional drawing of a three-core cable.

The cable 1 shown in the drawing is electric flameproof, mainly explosion and fireproof, flame retardant, including for intrinsically safe circuits, containing a core consisting of three conductive cores 2, each insulated with two-layer combined insulation, the first layer 3 adjacent to the named

the conductive core is extruded from silicone rubber, ceramizing under flame conditions, the second layer 4 is made of at least one mica tape imposed by a spiral winding with a mica coating inward, with the tape being tensioned during winding of at least 7 H, for identification over the winding An individual number is applied with contrasting ink or paint on each conductive core with a mica tape, the wires are twisted together in a core over which a bandage 5 is applied at least one ludinitic tape winding in a spiral with overlapping mica coating inward, and moisture-proof sheath 6 made by extrusion from a special polyvinyl chloride plastic compound with an oxygen index of at least 35 with low smoke and gas emission or a halogen-free polymer composition with an oxygen index of at least 35, or a polyolefin thermoplastic elastomer with oxygen at least 29, or a polyurethane thermoplastic elastomer with an oxygen index of at least 29, or silicone rubber with oxygen and Dex at least 29, including keramiziruyuscheysya under fire conditions.

Description of manufacturing technology.

Cable manufacturing technology according to the claimed utility model includes the following operations.

Copper wires for conductive conductors 2 are made of copper wire "wire rod", usually with a diameter of 8 mm by drawing. Depending on the diameter of the finished wire, the following operations can be used: coarse and medium drawing or coarse, medium and fine drawing.

To ensure softness, the wire is annealed in special annealing furnaces or in a passage for drawing operations. Annealing is not required to obtain tinned wires. Tinning is done hot, making the wire soft.

Multiwire conductive cores 2 are twisted from the required number of wires on twisting machines of a cigar, frame or lantern type.

The first layer 3 of two-layer combined insulation is applied from ceramicizable silicone rubber on continuous vulcanization units. The second layer 4 in the form of a winding with mica tapes with a mica coating inside is applied on tape winding machines with a tension of at least 7 H. Digital marking is applied using an ink printer to the passage.

Twisting of isolated conductors in groups - a pair, a three or a four or in the core is usually carried out on frame or lantern type machines.

An electric shield in the form of a braid or winding is superimposed on braiding or winding machines. Pre-possible cane (combining) of wires in bundles on reed machines.

An electric screen made of metal-polymer tape is applied by spiral winding with overlapping on winding machines or longitudinally with overlapping operations for applying a moisture-proof sheath. The screen is superimposed with metal inward, and a longitudinally tinned copper tinned drainage core is allowed under it. It is possible to longitudinally apply a screen made of metal-polymer tape with metal inward with a tinned copper drainage conductor while simultaneously applying a filler made of special polyvinyl chloride plastic compound, or a halogen-free polymer composition, or a thermoplastic elastomer on an extrusion line or silicone rubber on a continuous vulcanization line.

In the manufacture of a combined electric screen, the metal-polymer tape is allowed to run longitudinally with a metal layer overlapping upwards under the braid or winding on a braid or wrapping machine, respectively.

The mica bandage is made by spiral laying with overlapping on winding machines.

The shells on the screens are applied from a special PVC compound, or a halogen-free polymer composition, or a thermoplastic elastomer on extrusion lines or silicone rubber on continuous vulcanization lines.

A filler made of special polyvinyl chloride plastic compound, or a halogen-free polymer composition, or a thermoplastic elastomer is extruded on extrusion lines and continuous vulcanization lines using silicone rubber. The introduction of aggregate into the air voids of the core and groups is carried out by layer-by-layer extrusion, first for groups, then for each layer.

Foaming of the aggregate material is carried out chemically or physically. In the first case, granular, blowing agent is added to the granules of the main material in the hopper of the extrusion line, in the second case, inactive gas (for example: nitrogen) is introduced into the forming aggregate using a physical foaming unit. The physical method is advisable to use if there is a tape winding on the core.

A moisture-proof sheath made of special polyvinyl chloride plastic compound with an oxygen index of at least 35 with reduced smoke and gas emission or a halogen-free polymer composition with an oxygen index of at least 35, or a polyolefin thermoplastic elastomer with an oxygen index of at least 29, or a polyurethane thermoplastic elastomer with an oxygen index of at least 29, is applied to extrusion lines made of silicone rubber with an oxygen index of at least 29, including that which ceramics under the influence of a flame, on a units of continuous vulcanization.

The water blocking layer is superimposed by a water blocking tape in a spiral winding on a winding machine.

Armor made of round galvanized steel wires is applied in the form of a braid or winding on braiding or armoring machines, from steel tapes - according to the spiral winding method with overlapping on tape wrapping armoring machines. When using laminated steel tapes, the armor is imposed longitudinally using a special corrugating and coagulation unit together with the application of a moisture-proof sheath.

Experimental confirmation.

In order to verify the achievement of the technical result, a prototype cable was made corresponding to the one shown in the drawing, 1 km long.

Cable 1 contains a core of three stranded multi-wire copper conductors 2, with two-layer combined insulation with the first layer 3 in the form of extruded ceramicizing silicone rubber and the second layer 4 in the form of a winding of one mica tape with an overlap of 40% mica coating inside, with a bandage 5 on top of the core from one mica tape with an overlap of 40% mica coating inside, and a moisture-proof sheath 6 made of special polyvinyl chloride plastic compound with an oxygen index of at least 35 s Reductions dymogazovydeleniem.

Three cable samples of 1 m each were selected from the cable sample. The samples were tested for operability under the influence of a flame with a temperature of 850 ° C simultaneously with mechanical shocks under an operating voltage of 660 V for 180 min according to GOST 60 IEC 60331-31-2007. After 180 minutes, under the influence of a flame and 36 strokes on the steel ladder on which each sample was mounted during the test, all the test samples passed, that is, there was no electrical breakdown of insulation, and a voltage of 660 V was applied to the load. After that, the part that had been on fire cable length 400 mm in thin streams poured 5 liters of water. After exposure to water, the test samples passed: there was no breakdown of insulation, and the load had a voltage of 660 V.

This confirms the achievement of the technical result.

Claims (22)

1. An electrical fire-resistant cable, mainly explosion and fireproof, flame retardant, including for intrinsically safe circuits, containing a core consisting of at least one insulated single-wire or multi-wire conductive copper or copper tinned core, or at least one group of these cores, twisted into a pair or three, or four, and a moisture-proof sheath, characterized in that the insulation of the said conductive conductors is made of a two-layer combined, the first layer adjacent to the said conductive core is extruded from silicone rubber, ceramizing under flame conditions, the second layer is made of not less than one mica tape imposed by a winding in a spiral with overlapping mica coating inside, with the tape being tensioned during winding of at least 7 N, for identification over the winding An individual number is printed with contrasting ink or paint on each insulated core with a mica tape, and a bandage of at least one mica linen is applied over the core th winding helically overlapping mica coated inside. 2. The cable according to claim 1, characterized in that when the number of the named isolated cores or groups in the core is more than one, the cores or groups are twisted together into a core. 3. Cable according to any one of paragraphs. 1 or 2, characterized in that under the said insulation an additional layer of at least one mica tape is applied by winding in a spiral with overlapping mica coating inward. 4. Cable according to any one of paragraphs. 1 or 2, characterized in that on top of the aforementioned insulated core, a protective polymer tape is additionally applied by winding in a spiral with overlapping, on top of which the individual number of the insulated core is applied with contrasting ink or paint. 5. Cable according to any one of paragraphs. 1 or 2, characterized in that an extruded layer of silicone rubber is additionally applied on top of the said insulated core, which ceramizes under the influence of a flame, on top of which the individual number of the insulated core is applied with contrasting ink or paint. 6. The cable according to claim 5, characterized in that the additionally superimposed layer of silicone rubber of the named insulation of the named conductive conductors has an individual coloring or color marking, moreover, the coloring is made by the number of uniform colors sufficient to ensure that the named groups in the core differ from each other in the combination of colors named insulation or marking of insulation of conductive conductors and to ensure that these conductors are distinguished from each other by the color of the named insulation or the color of marking within each group and in the heart hechnik twisted from separate isolated conductive cores. 7. Cable according to any one of paragraphs. 1 or 2, characterized in that the adjacent groups have coordinated twisting steps, and the step of twisting into a group of two named isolated conductors does not exceed 0.1 m, three named isolated conductors does not exceed 0.15 m, four named isolated conductors does not exceed 0, 2 m 8. The cable according to claim 1, characterized in that it is made with at least one screen. 9. The cable according to claim 8, characterized in that the screen is made individual, superimposed on the named insulated conductive core, or group, superimposed on the named group, or common, superimposed on top of the core or a core bandage, and over each individual or group screen, a polymer shell or belt insulation is applied in an extrusion method in the form of a spiral winding with overlapping by at least one polymer tape, and the thickness of the said shell or zone insulation on individual or group screens is selected so that it can withstand test with a voltage of at least 500 V AC at a frequency of 50 Hz, applied between any individual or group or common screens. 10. The cable according to claim 8, characterized in that the screen is made of at least one metal-polymer tape, superimposed by the metal inside with a spiral winding overlapping or longitudinally with the shield wire laid underneath. 11. The cable according to claim 8, characterized in that the screen is made in the form of a winding or braid of copper or tinned copper wires. 12. The cable according to claim 11, characterized in that under the screen in the form of a winding or braid, it is additionally superimposed with metal upward with overlapping metal-polymer tape longitudinally or winding in a spiral. 13. The cable according to claim 9, characterized in that the said polymer sheath on top of an individual or group screen is made of special polyvinyl chloride plastic compound with an oxygen index of at least 35 with low smoke and gas emission or a halogen-free polymer composition with an oxygen index of at least 35, or a polyolefin thermoplastic elastomer with an oxygen index of at least 29, or a polyurethane thermoplastic elastomer with an oxygen index of at least 29, or silicone rubber with an oxygen index of at least 29, in including ceramizing under flame exposure. 14. The cable according to claim 1, characterized in that a polymer aggregate is applied over the core in a concentric layer. 15. The cable according to claim 14, characterized in that the filler is additionally inserted into the air cavities of the core and the said groups, providing for their partial longitudinal sealing. 16. The cable according to claim 14, characterized in that the filler is made of foam material. 17. The cable according to claim 14, characterized in that the filler is made on the basis of a special polyvinyl chloride plastic compound with an oxygen index of at least 28, with low smoke and gas emission, or a halogen-free polymer composition with an oxygen index of at least 28, or a polyolefin thermoplastic elastomer with an oxygen index of at least 28, or a polyurethane thermoplastic elastomer with an oxygen index of at least 28, or silicone rubber, with an oxygen index of at least 28, including that which ceramicizes under the influence of a flame neither. 18. The cable according to claim 1, characterized in that the moisture-proof sheath is made by extrusion from a special polyvinyl chloride plastic compound with an oxygen index of at least 35, with reduced smoke and gas emission or a halogen-free polymer composition with an oxygen index of at least 35, or a polyolefin thermoplastic elastomer with an oxygen index of at least less than 29, or a polyurethane thermoplastic elastomer with an oxygen index of at least 29, or silicone rubber with an oxygen index of at least 29, including ceramicizable in the presence of flame. 19. The cable according to claim 1, characterized in that for intrinsically safe cables the moisture-proof sheath is made in blue or with a longitudinal blue stripe. 20. The cable according to claim 1, characterized in that an armor made of round steel wires is additionally laid under a moisture protective sheath by winding along spirals or in the form of a braid, or from at least one steel tape wrapped in a spiral, or longitudinally from a pre-corrugated steel tape laminated with polymer. 21. The cable according to claim 20, characterized in that a layer of water-blocking material is additionally laid under the armor. 22. The cable according to claim 20, characterized in that the intermediate shell of a polymer material homogeneous with the material of the said moisture-proof sheath or winding of at least one polymer tape with an overlap is additionally applied under the armor by extrusion method.

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