VVG cable: specifications, types (ng, ls, fr)

Today it is almost impossible to live without electricity. More and more we depend on the availability of electricity, because the power grids accompany us everywhere – at enterprises, in public institutions, in houses and apartments, in summer cottages. Literally wherever a person spends at least some more or less long period of time. And most often, VVG cable and its modifications are used for wiring. 

VVG cable: scope

When laying / replacing wiring, other electrical work in private houses and apartments, the VVG cable is most often used. This is due to the wide scope and relatively low price. It can be used in electrical networks with a voltage not exceeding 1000 V and a frequency of 50 Hz (special types up to 100 Hz). That is, suitable for single-phase and three-phase networks. Can be mounted indoors and outdoors. For outdoor installation, additional protection is required. It is laid in HDPE pipes, cable trays, etc.

It is not recommended to use its pads in the ground, as it does not have armor, which is why it quickly fails. If desired, it can be laid in the ground, but in an additional protective sheath (corrugated pipe) and / or in a cable duct.

The scope largely depends on the modification: the type of material from which the sheaths of the cores are made and the cable itself. We will talk about this in more detail a little further.

Decryption and modifications

To understand the difference between different types of this cable, you need to know the decoding of the name. Then you can decide which type suits you best.

Regular VVG

Deciphering the main abbreviation – VVG – is simple:

• the absence of the letter A in front indicates that the conductors are copper;
• the first letter “B” indicates the core insulation material – PVC (polyvinyl chloride);
• the second letter “B” – the material of the cable insulation – also PVC;
• “G” – indicates the absence of additional protection (armor or other protective shells).

That is, the VVG cable consists of several copper conductors and PVC insulation. Each of the wires has its own color (read about color coding here). The conductors are twisted in one plane, protected by a PVC sheath. Conductors can be stranded or solid (coolant is added to the abbreviation).

In frequent homes, single-core cables are more commonly used. They can have 2, 3, 4 or 5 cores. The cable can be of round or flat section, with a zero core (blue) and/or with a ground core (yellow-green).

Non-flammable VVHng

In fire hazardous premises (wooden houses, bathhouses, etc.) and public buildings (children’s and medical institutions, in particular), flame retardant cables are required. In such cases, you can use products with reduced flammability – VVGng. Additional letters “ng” just indicate that the shell does not support combustion.

There are several more types of VVGng cable:

• VVGng-ls. They differ in that this plastic compound of the shells almost does not emit smoke when burned in an open fire. (ls is short for English low smoke). According to the new rules, it cannot be used in social institutions.
• VVGng-frls. Differs in increased reliability due to the fact that the conductors are additionally protected by two tapes containing mica. That is, each conductor is wrapped with thermal protection, on top of which a low-flammability plastic compound sheath is applied with minimal smoke emission. The insulated cores are twisted, on top of them there is an additional protective sheath – from two copper tapes with a thickness of at least 0,1 mm or a copper mesh entwined with one tape. On top of this protection, a PVC cable sheath is applied. This will be the VVGNG-FRLS cable. This type of cable can be used in industrial enterprises, including nuclear power plants, in hazardous areas except for class B-1 zones.
  

• VVGng-LSLTx. In this subspecies, for the sheaths of conductors and cables, a plasticizer with reduced flammability is used, which, when burned, emits a smaller amount of smoke and this smoke is less toxic. This conductor retains its working capacity in case of fire, it is used in networks with alternating voltage up to 1000 V, frequency up to 100 Hz or up to 1500 V at direct voltage. Can be used in social institutions.
• VVGng HF. This brand is different in that the smoke emitted during combustion (when the NG cable is directly on fire, it still burns) emits smoke with a reduced content of harmful substances. The abbreviation HF itself means that the shells are made of plastic with a reduced content of halogens (chlorine in particular), thereby reducing smoke toxicity (HF – from the English halogen free – halogen-free).

So, what is the difference between a conventional VVG cable and VVGng and its varieties? A conventional VVG conductor does not support combustion when laid alone. Products with the prefix “ng” do not burn even with group laying – in a bundle with other conductors. The rest of the “additives” to the name simply improve the performance.

Forms of release

Depending on the number and shape of the cores, the VVG cable can be round, flat, triangular or pentagonal (see photo below).

The shells are made of polyvinyl chloride of various modifications. The gaps between the cores are filled with the same plastic compound. In some embodiments, a tourniquet of the same material is used. With a small cross-section of the cores – up to 25 mm2 – it is allowed to release without filling.

The conductors in the cable are round or sectional. Sectional usually stranded, round – single-core. In any case, their cross section must correspond to the declared parameters (read how to check here).

Technical characteristics of the VVG cable

The features of using different types of VVG cable were discussed above, and now we will talk about the technical parameters of the conductors of this brand.

• Can be installed at temperatures down to -15°C. At lower temperatures, it is necessary to heat the cable, which is not easy to organize (the sheath becomes too rigid, it is very difficult to bend it).
• Operating temperature – from -50°C to +50°C. At the same time, with outdoor laying on the street, additional protection from ultraviolet radiation is required.
• You can bend with restrictions:
  • VVG with single-core conductors, the minimum bending radius is 10 radii;
  • with stranded – 7,5 radii (due to greater flexibility).
    

• Permissible conductor heating temperature:
  • at short circuit at which the conductors remain operational depends on the manufacturer can be from +160°C to +250°C.
  • during normal operation +70°C$
  • in overload mode +90°C.
• Fire resistance of VVG cables is at least 180 min.

It must be said that the technical characteristics of the VVG cable depend not only on the specific type, but also on the manufacturer. Therefore, before buying, see the cable passport (you can ask the seller). Above are the parameters common to all brands of VVG cable.

It is not surprising that these conductors are very popular – with good technical performance, they cost relatively little, they can be used almost everywhere – both in enterprises and offices, as well as in houses and apartments.

Cross section and number of cores

The cross section of the cores of the VVG cable of any brand can be from 1,5 mm² up to 240 mm². On sale are usually conductors with conductors up to 35 mm², other, larger sizes must be ordered.

As already mentioned, there are VVG cables with 2, 3, 4 and 5 cores. The number of cores is written immediately after the abbreviation: VVG 2 x 3,5; VVGng 4 x 4, etc. The first digit is the number of cores, the second is the cross section of the conductor.

There may be VVG cables with “neutral” and “ground” conductors. Moreover, there are options in which the protective wires are of the same cross section, there are ones with a smaller diameter (to save copper and lower cost). Most often, the “earth” conductor is made smaller; in some cases, the “neutral” is also made a little smaller. If the protective conductor has a smaller diameter, it is designated as +1. For example, VVGng 4 x 4,0 + 1 (read as 4 wires with a cross section of 4 mm² and 1 step less than 2,5 mm²). Such VVG cable options are also standardized, their parameters are shown in the table below.

continuous current

When selecting the cable section, a more correct technique is by maximum current. In this regard, such a characteristic as a long-term permissible current is normalized. It depends on the number and cross section of the cores, as well as on the laying method – open or closed.

Two modifications of VVG cables are produced – with a rated voltage of 0,66 kW and 1 kW.