Cables of the "NG" version, which are flame retardant when laid in a bundle with a normalized volume of combustible mass of cables in accordance with GOST 12176-89, section 3 (IEC 332-3-96), were developed in 1984-1986. Non-propagation of combustion depending on design cables was provided by the use of special protective thermal barriers or screens in cable structures, by limiting the volume of combustible materials, the use of polymer and other materials with low specific heat of combustion and polymer compositions with high oxygen index values. At the same time, cables of the “NG” version during combustion emit a large amount of smoke containing corrosive and toxic products.

In this regard, a set of works was carried out to create polyvinyl chloride compositions with reduced fire risk, on the basis of which it was developed and mastered New episode flame retardant cables with low smoke and gas emission "NG-LS". Index "LS" (low smoke)- compliance with the requirements for smoke generation during combustion of IEC 61034, parts 1 and 2.

Distinctive feature cables of the NG-LS version is that their insulation, filling and sheath are made of special polymer compositions of reduced fire hazard created on the basis of polyvinyl chloride. Cables of the "NG-LS" version differ from cables with the "NG" index in that, in addition to non-propagation of combustion, they are characterized by a reduced release of hydrogen chloride and a low smoke-generating ability during combustion and smoldering. Therefore, the use of cables with the index "NG" in subways Western Europe was banned in the late 1970s.

To solve the problems associated with the release of HCl and smoke, a class of cable materials has been created that do not contain halogens, that is, do not emit corrosive gases and have a significantly lower level of smoke emission - the so-called compositions. Cables using these materials are designated by the index "NG-LS HF". Index "HF" (halogen free) - compliance with the requirements for the corrosive activity of smoke and gas products during combustion, GOST R IEC 60754, part 2.

Polymer shell METALANGA corresponds to the index "NG-LS HF" fire safety standards. The combination of a polymer sheath with a metal hose ensures fire safety in the most adverse conditions.

Most types of equipment, instruments, tools and equipment in production, trade and everyday life are connected to the mains, which have an alternating voltage of up to 1 kV. And this means that in these networks the distribution and supply of electricity is carried out via a safe cable. Today, one of the most popular products for power supply and lighting in open and indoor areas is the VVG cable. There are options for its implementation.

Types and types of VVG cable

Any cable or conductor has a special marking by which you can determine the characteristics of the product.

Beginning electricians who are faced with abbreviations for the first time often do not understand the difference between VVGng and VVG, and also from VVGng-LS. Let's figure it out:

1. VVG is equipped with conventional PVC insulation, which does not have fire retardant and self-extinguishing qualities.
2. The insulating layer of VVGng contains halogen elements, due to which the combustion process is neutralized.
3. Sheath of current-carrying conductors VVGng-ls in the event of a fire, smoke and gas are not emitted due to the use of halogen-free polyvinyl chloride (this is a big plus for VVGng-ls).
4. VVGngfr-ls is a similar model, but fire resistant. If this type of cable ignites, the emission of gas and smoke is low. If you use a group gasket, then there will be no spread of combustion.
5. In the production of the VVGNG-fr-ls conductor, halogen-free materials are used that distinguish this product from other brands. Plastic made from halogen-free material has high level insulation and generates an amount of smoke within the normal range. Fire safety is the main feature of the VVG ngfr-ls type of cable.

What is VVG?

Often, in various instructions for electrical installation work, it is suggested to use a non-flammable conductor VVGng. In terms of quality/price ratio, it is the best option. This VVGng conductor is actually very versatile, because it is practical to use it in buildings made of flammable materials and in buildings that have high humidity.

What can labeling say? To begin with, consider what conductor markings exist. If you know the decoding of the letters in the given cable marking, then you can easily determine its properties. Below is a list of the main features by which it is quite simple to separate all conductors.

1. Material used for the production of conductive wire:

• no designation, it is copper;
• if the letter is A, it is aluminum.

2. The material from which the insulation is made for conductors:

• if the letter is B, then polyvinyl chloride was used;
• if the letters Pv, then polyethylene was used;
• if the letter P, then polymer insulation was used.

3. Cable armor:

• if the letter B, then armored;
• if the letter G, then there is no armor, a bare cable.

4. Sheath (outer insulation):

• if the letter P, then the shell is made of polymer;
• if the letters Shp, then there is a protective hose made of polyethylene;
• if the letters Shv, then the hose is protective;
• if the letter B, then the insulation is made of polyvinyl chloride.

5. Fire safety:

• if there is a marking ng-frhf, then during the group conduction of the conductor, combustion does not spread, during combustion and smoldering, corrosive substances are not formed in the form of gas;
• if there is a marking ngfr-ls, then during the group conduction of the conductor, combustion does not spread, the formation of smoke and gas is reduced;
• if there is a marking ng-hf, then during the group conduction of the conductor, combustion does not spread, during combustion and smoldering, corrosive substances are not formed in the form of gas;
• if there is a marking ng-ls, then the gas and smoke emission is reduced, with the group conduction of the conductor ng-ls, combustion does not spread;
• if there is a marking ng, then with the group conduction of the conductor, combustion does not spread;
• if there is no marking, then when laying a single conductor, combustion does not spread.

If you follow the above, then you can decipher the abbreviation VVGNG: the first letter B means that the insulation of the conductive cores was made of polyvinyl chloride, the second letter B indicates that the insulation of the outer sheath was also made of polyvinyl chloride, the third letter G indicates that there is a special layer of protection, there is no armor.

In the professional language of electricians, the abbreviation VVG means approximately: the letter B is vinyl, the letter B is vinyl, the letter G is naked. And the letters ng say that if you use a group gasket of this conductor, it will not support combustion. This is an important indicator for cases when it is necessary to lay the conductor in places where there is a high probability of fire. After all, the main thing is safety. There is no letter A in the marking, which means that the conductor has conductive conductors made of copper.

This conductor is made in two modern modifications: with the ending ng-ls - this means that during combustion there is a reduced emission of smoke and gas (this is what ng-ls is good for); with the ending ng-hf - this means that during the burning of the cable there is no release of corrosive substances in the form of gas. These modifications have improvements - this is fr (in other words, fire resistance, which distinguishes it from ng-ls).

Often with the usual VVG you can find cables that have the letter "P" at the end of the marking. Judging by the technical data, they do not differ, and the slight difference lies in the structure - it is flat. And this means that the decoding of the cable VVG p it sounds like this: the letter V is vinyl, the letter V is vinyl, the letter G is naked, the letter P is flat.

Cable routing options

Laying VVG cable in an open way

If follow technical parameters this cable, its open laying is only allowed on surfaces and structures made of flame-retardant or non-combustible materials eg gypsum, concrete, brick, plastered surface, etc.

VVG cable laying open way allowed to be used under suspended structures, such as a cable, etc. These structures are required to provide a sufficiently reliable laying. When laying the cable, any possibility of mechanical action on it should be excluded.

If there is a risk of damage mechanically cable product, the necessary additional protections should be installed. Additional protection should be used when laying a cable product in an open way on combustible wooden surfaces. Installation in this case should be carried out using a cable channel, corrugated hose, metal hose, pipe and other types of protection.

Laying VVG cable in a hidden way

This cable routing option remains the most popular for residential premises. Cable laying under plaster, in voids, in furrows, etc.

With this laying option, mechanical damage is practically excluded, so the use of additional protection is not expected, with the exception of wall voids in wooden houses.

Here it is allowed to carry out hidden cable laying in pipes or in other non-combustible materials. Available regulations that relate to hidden electrical wiring. They define correct execution hidden method of cable installation.

Laying the VVG cable in the ground

It is known that it is not allowed to lay a cable of this brand underground without the use of special protection methods. All this is due to the fact that there is no protection that will keep the cable from any mechanical influences.

Underground installation of the VVG conductor is possible only in special sealed boxes and only along overpasses and cable structures.

DESIGN

1. CONDUCTING CORE- copper, single-wire, round shape, class 1 according to GOST 22483, with a nominal section up to 16 mm 2 inclusive.

2. INSULATION- from a polyvinyl chloride composition of reduced fire hazard. Insulated conductors multicore cables have distinctive colors.

3. INSULATED CORE- laid in the same plane.

4. INNER EXTRUDED SHELL- superimposed on insulated cores, laid in the same plane, from a PVC composition of reduced fire hazard, which fills the gaps between the cores. Thickness inner shell not less than 0.3 mm.

5. OUTER SHELL- from PVC of a composition of the lowered fire risk. For cables with a cross section of round conductive conductors up to 16 mm 2, it is allowed to apply an outer sheath with simultaneous filling of the gaps between the conductors. In this case, the inner extruded shell is not superimposed.

APPLICATION

Flame-retardant cables with low smoke and gas emission are designed for the transmission and distribution of electricity in stationary installations for a rated alternating voltage of 0.66 kV and 1 kV at a frequency of 50 Hz. Cables are manufactured for general industrial use and for nuclear power plants when supplied to the domestic market and for export. The cables are designed for operation in cable structures and premises, including for use in systems of nuclear power plants of classes 2, 3 and 4 according to the classification OPB-88/97 (PNAE G-01-011-97).
brand cables VVG-P ng(A)-LS do not spread combustion when laid in bundles.

SPECIFICATIONS

Type of climatic version of cables B, placement categories 1-5, placement category 5 according to GOST 15150-69
Operating temperature range	from -50°С to +50°С
Relative air humidity at temperatures up to +35°С	up to 98%
Laying and installation of cables without preheating is carried out at a temperature not lower than	-15°C
Minimum bending radius when laying	7.5 outer diameters
Rated frequency	50 Hz
Test alternating voltage with a frequency of 50 Hz:
for voltage 0.66 kV	3 kV
for voltage 1 kV	3.5 kV
for a long time allowable temperature heating of cable cores during operation	+70°C
The limiting temperature of the current-carrying conductors of cables according to the condition of non-ignition of the cable at short circuit.	+400°C
Construction length of cables for sections of main conductors:
1.5 to 16 mm2	450 m
when delivered in coils, it is agreed between the consumer and the manufacturer
Warranty period of operation	5 years from the date of putting the cable into operation, but no later than 6 months from the date of manufacture
Cable life	30 years

Wire and cable VVGng LS is the top of the family of cable products with the abbreviation VVG, the secret of its privilege is the postscript LS, what it indicates and what it hides, we will analyze in detail in this article.

Smoke in the premises is considered the most important factor that increase the risk negative consequences in case of fire. In the event of a fire at industrial facilities and large public buildings, cable routes become one of the main sources of smoke. The sad experience of the Ostankino television tower, the Manege and other disasters of the last decade only confirmed this truth.

At present, documents technical regulation the types of cable products that can be used in group laying inside public and industrial premises(GOST R 5315-2009). Here, in addition to the condition of non-propagation of combustion (-ng), one of mandatory requirements there was a low smoke and gas emission during combustion or smoldering of the cable.

Designation LS, order of assignment

The decoding of VVGng LS is as follows:

• There is no letter A at the beginning of the marking, which means the cable is copper;
• B - the outer insulating layer consists of PVC insulation;
• B - core insulation consists of PVC insulation;
• ng - does not spread combustion with single and group laying;
• LS- L ow S moke (translated from english easy smoke)

In the marking VVGng (..)-LS, after the category through a hyphen is the designation LS, indicating low smoke and gas emission ( L ow S moke). Of course, such an index can be assigned to a cable only in case of a successful test for such an indicator. The standard test procedure for smoke generation during combustion and smoldering, installation description, etc. are given in GOST R IEC 61034 -1 (2) -2005.

The principle of the test is to measure the transparency of the air in the chamber with the cable before and after combustion. The smoke resulting from the combustion of the sample reduces the light transmission of the volume, which is recorded by the instruments. The result of the test will be the ratio of light transmission before and after the experiment, expressed as a percentage. In accordance with GOST R 53769-2010, it is considered that the cable has successfully passed the test if the smoke has reduced transparency by no more than 40%. In this case, the manufacturer has the right to put the LS index in the marking.

Cable insulation with low smoke emission

For the production of VVGng LS cable, PVC compounds of reduced fire hazard are required, and, in contact with fire, they should not give a large number smoke. In addition, it is required that the smoke be minimally toxic (the toxicity index is not more than 40 mg / m 3 according to GOST R 53769-2010).

The task is difficult, but it was successfully solved by selecting special additives - antipyrines and additives. Today, such plastic compounds are produced both in Russia and abroad. domestic producers registered several technical specifications, for example, technical specifications 2246-001-25795756-2009 and produce plastic compounds based on them, specialized for core insulation, internal filling and outer shell(brands PPI 30-30, PPV-28, PPO30-35, respectively).

Cable structure VVGng LS

The composition and arrangement of the elements of the VVGng (..) -LS cable is no different from its counterparts - cables with copper conductors, with PVC insulation and sheath according to GOST 53769-2010. External similarity is clearly visible in the image shown in this section.

The VVGng(..)-LS cable can be round or flat, the maximum number of cores is five. The cores themselves can be single-wire or multi-wire, round or sector. Rated values cross-sectional areas are selected from a single standard series for all.

VVGng LS cable specifications

Since the characteristics of the entire family of cables with PVC core insulation and sheath are standardized by one standard GOSTR 53769-2010, they vary only within small limits for different manufacturers. The standard does not introduce separate indicators for the cross-sections and shape of the cores, the thickness of the insulation of conductors and the sheath, electrical resistance etc. for cables with plastic insulation with reduced smoke generation. They go along with the whole family of PVC compounds. Separate values ​​are given for XLPE insulation, etc.

GOSTR 53769-2010 provides for -LS products some difference in minimum tensile strength, it may be less than that of VVG, but does not differ from VVGng. Therefore, the section "VVGng LS cable specifications"in terms of general characteristics, it practically does not differ from the section of the same name in the article, the cable of the VVG brand. Familiarize yourself with general characteristics VVGng(..)-LS is possible.

Application of cable VVGng(..)-LS

Cables VVGng - LS related to fire hazard classes P1.8.2.1.2 and

P1.8.2.2.2 can be used for group laying in residential and public buildings, internal and external cable structures on industrial enterprises. It is allowed to use the cable at nuclear facilities.

Other cable options

• - round copper wire with PVC insulation of the outer and inner layers, has low gas and smoke emission during combustion with single and group laying;
• VVG-P - the same as VVG, but flat design;
• - round copper wire with PVC insulation of the outer and inner layers, has low gas and smoke emission during combustion with a single laying;
• VVGng-P - the same as VVGng, but flat design;
• VVGng-ls - round copper wire with PVC insulation of the outer and inner layers, has low gas and smoke emission during combustion in single and group laying;
• VVGng-Pls - the same as VVG-ls, but flat design;
• VVGng-frls - round copper wire with fire-resistant PVC insulation of the outer and inner layers, has low gas and smoke emission during combustion in single and group laying;
• VVGng-Pfrls - the same as VVGng-frls, but flat design.

According to the designation of brands of cable products intended for group laying, letter indices should be added indicating the compliance of cable products with the requirements for flame retardance:

• ng(A F/R) - fire hazard indicator PRGP 1а (category A F/R);
• ng(A) - fire hazard indicator PRGP 1b (category A);
• ng(B) - fire hazard indicator PRGP 2 (category B);
• ng(C) - fire hazard indicator PRGP 3 (category C);
• ng(D) - fire hazard indicator PRGP 4 (category D).

Features of tests for various categories

• For category A F/R (applies only to power cables with a conductive core cross section of more than 35 mm2), the cables are fixed on a test ladder to obtain a total nominal volume of non-metallic material of 7 liters per 1 m of the test specimen. Flame exposure time - 40 min. This category designed for special cable designs used in specific laying conditions in accordance with the requirements specifications on the cable. Category A F/R is not intended for general use.
• For category A, the cables are fixed on the test ladder to obtain a total nominal volume of non-metallic material of 7 liters per 1 m of the test specimen. Flame exposure time - 40 min.
• For category B, the cables are fixed to the test ladder to obtain a total nominal volume of 3.5 liters of non-metallic material over a length of 1 m of the test specimen. Flame exposure time - 40 min.
• For category C, the cables are fixed on the test ladder to obtain a total nominal volume of non-metallic material of 1.5 liters per 1 m of the test specimen. Flame exposure time - 20 min.
• For category D, the cables are fixed on the test ladder to obtain a total nominal volume of non-metallic material of 0.5 l per 1 m of the test piece. Flame exposure time - 20 min.

The length of the charred part of the sample, measured from the lower edge of the burner, should not exceed 2.5 m

Cable products should be subdivided according to fire hazard indicators into the following types of execution:

Type of cable product	Type decoding	Fire hazard class	Preferred field of application
No designation	Flame-retardant cable products when laid alone	O1.8.2.5.4	For single laying in cable structures and industrial premises. Group laying is allowed only in outdoor electrical installations and industrial premises, where only occasional presence is possible service personnel, it is necessary to apply passive fire protection
ng(A F/R)	Flame retardant cable products for group laying	P1a.8.2.5.4	For laying, taking into account the volume of combustible load of cables, in open cable structures (trestle bridges, galleries) of outdoor electrical installations
ng(A)		P1b.8.2.5.4
ng(V)		P2.8.2.5.4
ng(C)		P3.8.2.5.4
ng(D)		A4.8.2.5.4
ng(A F/R)-LS	Cable products that do not spread combustion during group laying, with reduced smoke and gas emission	P1a.8.2.2.2	For laying, taking into account the amount of combustible load of cables, in internal electrical installations, as well as in buildings, structures and closed cable structures
ng(A)-LS		P1b.8.2.2.2
ng(B)-LS		P2.8.2.2.2
ng(C)-LS		P3.8.2.2.2
ng(D)-LS		A4.8.2.2.2
ng(A F/R)-HF	Cable products that do not spread combustion during group laying and do not emit corrosive gaseous products during combustion and smoldering	P1a.8.1.2.1	For laying, taking into account the volume of combustible load of cables, in internal electrical installations, as well as in buildings and structures with mass stay people, including in multifunctional high-rise buildings and building complexes
ng(A)-HF		P1b.8.1.2.1
ng(B)-HF		P2.8.1.2.1
ng(C)-HF		P3.8.1.2.1
ng(D)-HF		P4.8.1.2.1
ng(A F/R)-FRLS	Fire-resistant cable products, flame retardant during group laying, with reduced smoke and gas emission	P1a.7.2.2.2	For laying, taking into account the amount of combustible load of cables, in systems fire protection, as well as other systems that must remain operational in a fire
ng(A)-FRLS		P1b.7.2.2.2
ng(B)-FRLS		P2.7.2.2.2
ng(C)-FRLS		P3.7.2.2.2
ng(D)-FRLS		P4.7.2.2.2
ng(A F/R)-FRHF	Fire-resistant cable products that do not spread combustion during group laying and do not emit corrosive gaseous products during combustion and smoldering	P1a.7.1.2.1
ng(A)-FRHF		P1b.7.1.2.1
ng(B)-FRHF		P2.7.1.2.1
ng(C)-FRHF		P3.7.1.2.1
ng(D)-FRHF		P4.7.1.2.1
ng(A F/R)-LSLTx	Flame-retardant cable products in group laying, with reduced smoke and gas emission and low toxicity of combustion products	P1a.8.2.1.2	For laying, taking into account the volume of combustible load of cables, in buildings of preschool and educational institutions, specialized nursing homes and disabled people, hospitals, in dormitory buildings of boarding schools and children's institutions
ng(A)-LSLTx		P1b.8.2.1.2
ng(B)-LSLTx		P2.8.2.1.2
ng(C)-LSLTx		P3.8.2.1.2
ng(D)-LSLTx		P4.8.2.1.2
ng(A F/R)-HFLTx	Cable products that do not spread combustion during group laying, do not emit corrosive gaseous products during combustion and smoldering, and with low toxicity of combustion products	P1a.8.1.1.1
ng(A)-HFLTx		P1b.8.1.1.1
ng(B)-HFLTx		P2.8.1.1.1
ng(C)-HFLTx		P3.8.1.1.1
ng(D)-HFLTx		A4.8.1.1.1
ng(A F/R)-FRLSLTx	Cable products are fire-resistant, flame retardant during group laying, with reduced smoke and gas emission and low toxicity of combustion products	P1a.7.2.1.2	For laying, taking into account the volume of combustible load of cables, in fire protection systems, as well as in other systems that must remain operational in a fire, in buildings of preschool educational institutions, specialized nursing homes and disabled people, hospitals, dormitory buildings of boarding schools and children's institutions
ng(A)-FRLSLTx		P1b.7.2.1.2
ng(B)-FRLSLTx		P2.7.2.1.2
ng(C)-FRLSLTx		P3.7.2.1.2
ng(D)-FRLSLTx		P4.7.2.1.2
ng(A F/R)-FRHFLTx	Cable products are fire-resistant, flame retardant during group laying, do not emit corrosive gaseous products during combustion and smoldering, and with low toxicity of combustion products	P1a.7.1.1.1
ng(A)-FRHFLTx		P1b.7.1.1.1
ng(B)-FRHFLTx		P2.7.1.1.1
ng(C)-FRHFLTx		P3.7.1.1.1
ng(D)-FRHFLTx		P4.7.1.1.1