The popular VVGng-LS cable is designed for wiring equipment indoors, outdoors, electrical installation products (channels, tunnels, pipes, trays, etc.) provided there are no tensile loads on the product. The equipment of this series is also used when it is necessary to ensure increased fire safety.
VVGng LS differs from the VVGng cable in that its design uses insulation that is not capable of emitting a large amount of smoke during smoldering.
In the name of the wire, the index LS means Low Smoke, which means “low smoke” (insulation and sheath are made of fireproof plastic compound that does not spread combustion).
Application
VVGng-LS cable is designed for use in cold, temperate or tropical climates. This type of wire can be used both on land and in lakes, rivers at an altitude of up to 4300 m.
Power cable used:
- in the air provided there is no threat of mechanical damage during operation;
- indry or damp rooms (sewers, tunnels, channels, industrial premises, structures subject to partial flooding, etc.);
- in blocks, on bridges, special cable racks;
- in hazardous areas;
- in fire hazardous facilities;
- for laying lighting group networks in hazardous areas.
The weight of the VVGng-LS cable allows it to be used for vertical, horizontal or inclined routes. This type of unarmored wire can be used in places with vibration.
It is not recommended to use for underground laying (in earthen trenches and in the ground) without the use of special protective cable systems (for example, metal hose or HDPE pipes), which exclude damage to the conductor sheath and retain its performance characteristics throughout the entire service life.
Design features
- Conductive conductors are made of copper and can be single or multi-wire, have a sector or round shape. GOST provides I or II class of flexibility.
- Core insulation is made of polyvinyl chloride plastic compound, which has increased fire protection and reduced smoke emission. Each insulated core in multi-core cables is made of PVC in different colors. Traditionally, zero conductors are blue, grounding is yellow-green or marked with the number "0".
- The inner sheath of the cable is superimposed over the insulated cores, filling the voids between them and creating between the outer insulation andcore additional refractory protective layer.
- The outer shell is made of polyvinyl chloride composition and has an increased fire resistance. If the diameter of the cable cores does not exceed 16 mm, it is permissible to fill the space between the core and the outer sheath with a special refractory composition. In this case, the inner shell is optional.
Cable diameter VVGNG-LS
The cores of a twin-core wire have the same cross-sectional diameter. If the number of cores is 3-5, one of them may be of a smaller diameter. This is a ground or neutral wire.
The diameter and weight of the VVGng-LS cable are calculated depending on the number of conductive cores in the structure, its design features, etc.
Main Specifications
VVGng-LS cable is used when laying and installing electrical networks from power distribution boards or transformer substations to energy-consuming objects: production shops, residential and office buildings, construction sites, household and municipal enterprises, etc. Laying is allowed power wires in concrete trays, tunnels, on supporting overpasses.
The wire is designed to transmit electricity, the power of which is 0.66 kV for alternating current or 1 kV for direct current.
The outer shell is made of materials that are not affected by ultraviolet radiation, therefore laying the product in the open sun is allowed. VVGng-LS cable is not recommended for use forlaying in unprotected earthen trenches.
- Admissible air temperature at which the cable can be used for a long time is -50…+50 °С
- Humidity allowed up to 98% (at +35°C)
- Cable laying is allowed at temperatures not lower than -15 °С
- Working t of core heating - +70 °С
- Maximum t in emergency mode - +90 °С (operation no more than 8 hours a day and no more than 1000 hours throughout the entire period of service)
- Insulation non-ignition at t +400 °С
- The length of the cable, the diameter of the cores of which is 1.5-16 mm, is 450 m; for a cable with cores with a diameter of 25-70 mm - 300 m; if the core diameter is 95 mm or more - 200 m.
- Guaranteed operational period from the date of commissioning - 5 years, from the date of manufacture - no more than 6 months.
- Use up to 30 years
Quality control
The control methods given below make it possible to draw a preliminary conclusion about the quality of the cable, if the obtained values differ significantly from the regulated ones. However, the final conclusion on the compliance of this material with GOST can only be made after it has been tested in a specialized laboratory according to strict methods and in the volumes specified in the standard.
Visual inspection and measurement of dimensions
Visually you can check the number and color of the cores, the number of wires in the core, the integrity of the sheath and insulation, the ease of their separation.
With helpmeasuring tools can check the thickness of the sheath and insulation. Measuring the diameter of the wire and calculating the cross section of the wires using a special formula does not apply to a strict control method, since the compliance of the cross section confirms the electrical resistance. But nevertheless, a significant deviation (by more than 10%) of the calculated cross section from the nominal one can become a reason for doubting the quality.
Coil test after low temperature exposure
In this way, when having a large freezer with a temperature of up to -15 ° C, the quality of the cable sheath is checked, the outer diameter of which is up to 20 mm. To do this, a piece of cable (approximately 1.2 m long) rolled into a ring for compactness is placed in the freezer for 45 minutes, then taken out and winded onto the drum with a full turn for 5 minutes. The drum diameter should be 15 ∙ (Dn + d) ± 5%, where Dn is the outer diameter of the VVGng-LS cable in mm, d is the core diameter in mm. At the same time, a high-quality shell should not have cracks and breaks.
