Electrical equipment today is presented on the market in a wide range. Among such products, VVGng wire is especially popular.
For those who decide to carry out the wiring of low-voltage internal and external electrical networks, experienced craftsmen recommend using this particular conductive equipment. Information about the VVGng wire and its technical characteristics is presented in this article.
What is the product?
VVGng wire is a type of VVG power cable, which is used to supply power to indoor equipment, as well as to external cable structures and electrical appliances. Structurally, the VVG cable (GOST 16442-80) is represented by one or more conductive cores, each of which is equipped with its own insulating coating. In a power cable, the cores are twisted together and contain a common insulating sheath.
Abbreviation
The first letter in the electrical conductive system indicates the material from which the core is made. If it were aluminum, then the abbreviation on this wire would begin with the letter "A". Since it is absent in the VVG grades, it means that the cores of all products are copper.
The letter "B" indicates the material from which the insulating coating is made: vinyl (polyvinyl chloride). Since "B" is in the abbreviation twice, this means that the VVGng wire (GOST 53762-2010) is equipped with double vinyl insulation. Polyvinyl chloride is used to make the wire winding and the outer insulating layer.
The presence of the symbol "G" in the designation indicates that the cable does not contain armor. Due to this, the wire has sufficient flexibility, but at the same time it is not protected from external mechanical influences.
What is the difference between VVGng and VVG wire?
When electrical conductive products are laid alone, they do not ignite. When laying VVGng together with other wires, in order to prevent cable burning, it is treated with a special anti-flammable solution. This is indicated by the designation "NG". For the basic VVG cable, ordinary PVC insulation is provided, therefore it is not characterized by the presence of self-extinguishing and fire-retardant properties.
Types of wires
- VVG. Basic model with conventional PVC insulation. Wire laying together may ignite.
- VVGng. The insulating layer is equippedspecial halogen chemical elements that prevent the ignition of the cable.
- VVGng Is. The wire is equipped with an insulating sheath made of halogen-free PVC. With the help of this type of VVG cable, electrical energy is distributed and transmitted to equipment belonging to a similar voltage class. Due to its inherent technical characteristics, the VVGng ls wire is primarily used in places with a particularly high probability of fire. The wire in the marking is also supplemented with the designation (Low Smoke).
- VVGng-frls. The insulation layer of this wire is also made of halogen-free materials. The cable is fire retardant. When the plastic insulation of this wire smolders, a small amount of smoke is released.
Strands
This element is the basis of any conductive electrical product. The VVGng wire may contain one or more copper conductors. Their number varies from 1 to 5. How many lived in the cable can be judged by its marking. Their number is indicated by the very first digit. For example, the wire VVGng 3x 2, 5 is equipped with three copper conductors. Structurally, each of them can be a separate copper wire, or several, twisted together.
You can also determine this by marking. The designation "M" stands on those cables that contain stranded copper conductors. Conversely, "0" is available on solid core products.
Shape
Depending on how the cores are laid in the wire, VVGng products can be:
- Round. Cables that contain cores with small sections have this shape. Rounded wires are marked with the letter "K".
- Segmental, or sectoral. Each of the veins is given the shape of a certain part of the sector of the circle. Such wires are designated with the symbol "C".
- Flat. In such wires, the cores are laid along the same plane. This shape is typical for wires with a small cross section.
Section
In VVGng electrical products, this parameter varies from 1.5 mm square. up to 50 mm sq. The number of sections is indicated by the second digit. For example, in a VVGng 3 x2 5 wire, the cores have a cross section of 2.5 mm2. Nevertheless, there are also wires, the cross section of which can be 400 mm. sq. However, these cables are made to order. If the parameter is 4 mm square, this does not mean that all five cores of the VVGng wire have exactly this section. 2.5 sq. mm is considered their optimal indicator, since the cross section of the neutral conductor and the ground conductor is usually smaller.
The equipment with the larger cross-section index has the best conductivity. Conductivity is measured as the resistance of a conductor per thousand meters of length. For example, a cable with a cross section of 1.5 mm2. has a resistance of up to 12 ohms, and a product with a cross section of 50 mm square. – 0.39 Ohm.
The wire can be operated if the length of a thousandmeters, its resistance will be in the range of 7-12 ohms. The resistance indicator is measured at a temperature not higher than 20 degrees.
Insulating cover
The thickness of the insulation depends on such parameters of the wire as its nominal section and the voltage for which it is designed. With a cable cross section of 16 mm. sq. and voltage not more than 660V, the thickness of the insulating coating is 0.9 mm. If this wire will be operated at a voltage of 2.5 kV, then the insulation thickness should be 1 mm. For wire VVGng 3x2 5 mm square. at a voltage of 0.66 kV, it will not exceed 0.60 mm. For operation at 1 kV, the nominal insulation thickness will be 0.70 mm.
Voltage
Before use, the wire must be electrically tested. The product, which is designed to operate at a voltage of 66 kV, is first tested for 10 minutes at a voltage of 3 kV. A wire rated for 1 kV must withstand 3.5 kV.
Bendable
According to GOST, each wire, depending on the type, has certain mechanical characteristics. Those products that use stranded conductors can be bent to a radius of 7.5 cable diameters. Single-wire products are easily bent to a radius of 10 diameters.
Temperature
Indicators of the nominal temperature of the cable vary from -50 to +50 degrees. The optimum temperature for wire installation is: - 15 degrees. It is not recommended to work with the cable at lower temperatures. Otherwise, according to electricians, the product will crumble and may evenbreak down.
Description of wire VVGng 3x2, 5
The product consists of three conductive copper wires. Polyvinyl chloride plastic (PVC) is used as an insulator. This material is also used as a winding. The wire at group laying does not ignite. The product is not provided with a protective cover.
Technical data at 0.66 kV
This conductive product at the specified voltage value has the following parameters:
- The nominal cross section of the core is 2.5mm sq.
- A wire one thousand meters long weighs 135 kg.
- The cross-sectional diameter is 9.3 cm.
- The insulating coating of the cores has a thickness of 0.60 mm.
- The stranded product has a minimum bend radius of 7 cm. If the core contains one wire, then the bend radius is 93 mm.
- The wire is rated for 37 A (ground) and 28 A (air).
- In case of a short circuit, 0.27 kA is considered acceptable for the wire.
- The electrical resistance of the insulating layer does not exceed 10 MΩ.
Characteristics of the wire at a voltage of 1 kV
With the specified voltage value, VVGng 3x2, 5 has the following parameters:
- Cross section: 2.5mm sq.
- A thousand meters long wire weighs 144 kg.
- The stranded product has a minimum bending radius of 0.73 cm, and the single wire strand is designed for bending with a radius of 0.97 cm.
- Insulation layer thickness is 0.70mm.
- The electrical resistance of the insulation per 1,000 meters is 10 MΩ.
Wires are sold in twisted form, in drums. Their length varies from 500 to 7200 meters.
Application
The place for laying VVGng wires can be:
- Dry and damp areas: tunnels, canals, galleries, mines, sewers, industrial areas.
- Partially flooded structures with mild, moderate or severe corrosivity.
- Special cable racks of blocks and bridges.
- Premises in residential and public buildings.
- Fire hazardous premises.
- Explosive areas.
Conclusion
The operational warranty period of the wire is at least five years. According to consumers, VVGng can be used for much longer. The demand for this conductive product is explained by the ratio of its high technical characteristics and relatively low cost.
