KG cable – a very flexible conductor, with special properties of the insulating coating. It is the insulating material that determines the peculiarities of the operating conditions of this type of wire. This type of power conductor is very popular among electricians and is most often used to connect powerful electrical appliances, in particular – a welding machine. Very often KG cable is used not only to connect the welding machine, but also gantry cranes, excavators.
Due to its flexibility and good technical characteristics, the CG cable is actively used to connect powerful large-scale installations to the network, both stationary stationary and in-shop equipment, and portable devices, power units. Technical parameters allow to use on the street at various temperatures, and indoors.
When choosing a cable, its parameters such as the number of cores, cross section and outer diameter of the product are important. Since the industry produces dozens of their varieties, one of the most popular cross-section cable KG 1×2,5, 1×4, 1×6, 1×10, 1×16, 1×25, 1×35, 1×50, 1×70, 1×95, 1×120, 2×2.5, 2×4, 2×6, 2×10, 2×16 , 2×25, 2×35, 2×50, 2×70, 2×95, 2×120, 3×4, 3×6, 3×10, 3×16, 3×25, 3×35, 3×50, 3×70, 3×95, 3×120, the price depends on several factors, the number of cores and their cross section.
Rubber is a very good dielectric. This makes the operation of this brand of cable reliable and safe, provided that the manufacturer’s recommendations for its use (products are intended). Power cable in a flexible sheath is very popular. It is used as a welding cable, as well as in electrical wiring.
Deciphering of KG marking
In this case, deciphering the abbreviation KG about the product itself is quite simple. “K” – means the cable, and “G” – the product belongs to the class of flexible.
This brand of cable is distinguished by the fact that it has rubber insulation. Unlike polyvinyl chloride, rubber is extremely flexible and soft. There are no restrictions on the number of compressions and stretches. It works almost until the moment of self-destruction, which occurs as a result of the natural aging process. And this process can take more than a decade, depending on operating conditions.
The conductive core is twisted from thin (sometimes tinned) copper wires. Multi-wire cores are covered with rubber insulation.
KG cable structure:
– outer shell;
– multi-wire core;
– core insulation.
In a design of products there can be options: depending on features of a design, isolation of cores can be from silicone rubber or it can be not at all in single-core cables of big section. The only copper core, or their entire package can be contained in a thin synthetic film PET-E, which is used as additional protection of the cores. This whole structure is covered with a rubber shell.
The conductive core consists of thin copper tinned wires, which belong to the 5th class of flexibility. This is a high class, which guarantees a significant number of possible cable bends. This number can reach 30 thousand times.
Digital marking is performed by numbers starting from the number 1 and onwards. The ground wire is marked with the number “0”. When marking with color, three colors are used:
The grounding has a yellow-green color.
The KG cable can be divided by the number of conductive cores, and by the cross sections of the cores, which determine the power that can withstand the cable:
1-core cable is characterized by a cross section of 2.5-50 mm
2- and 3-core cables have a core cross section of 1-150 mm
The 4-core cable is made with cores of 1-95 mm
5-core cable can have a core cross section of 1-25 mm
The manufacturer may also have other nomenclatures of the design of the cores and their cross section. The conductor of the earthing circuit is always made by the intersection of fewer phase cores.
The number of conductive cores varies in the range from 1 to 5 pcs., With a cross section from 1 mm 2 to 240 mm 2. For their insulation uses rubber RTI-1 or RTI-2-HL. The outer sheath is made of rubber type RSHT-2, RSHTM-2 or RTISH (used in single-core cables).
The main advantage of the KG brand is flexibility. However, the bending radius is limited to eight wire diameters. Moreover, this radius is determined only by the flexibility class of copper cores (class 5). The number of bends does not affect other characteristics of the cable:
– the upper permissible limit of the working temperature of the cores is 75 ºC;
– ability to function in different conditions: indoors and outdoors, regardless of humidity and other weather conditions;
– operation is allowed in the ambient temperature range from -40 ºC to +50 ºC;
– this brand of cable is suitable for both DC and AC operation. The product is most often used to supply power to portable equipment running on the mains. The KG cable is designed to operate at a nominal AC voltage of 660 volts.
– the maximum allowable operating voltage with which the current-carrying cores cope should not exceed 720 volts. When using direct current, the cable can withstand operating voltages up to 1 kV.
– tensile force, the total cross section of all cores, should not exceed 19.6 N / mm 2. With active operation, the minimum service life is 4 years. However, the product does not withstand significant mechanical loads.
– KG insulation resistance – not less than 50 kО per meter.
The main purpose of the KG cable brand is to connect portable electrical appliances to the mains. It can be used:
– on platforms under a canopy;
– on the decks of ships;
– in different climatic zones, in any weather conditions.
Usually the cable is laid on the ground or on the surface of an asphalt or concrete platform. The wires are removed after completion of work. The main condition is to prevent significant mechanical effects on the outer shell.
The softness of the rubber, which makes the cable insulation invulnerable to bending, can cause it to break due to mechanical action. For example, a collision with a vehicle or a fall on the wire of a heavy object can cause it to malfunction. Multicore products are very sensitive to such actions, especially those which do not have an external lining. The presence of an external gasket enhances the protective properties of the cable.
Rainwater, puddles and dirt do not affect the performance of products with flexible rubber insulation. The outer sheath of this cable is made of special rubber, resistant to mold, which destroys the insulation.
You can connect to the CG cable:
– mobile grain cleaning mechanisms;
– power tools;
– construction electrical equipment: concrete mixers, electric lifting devices, etc .;
– devices for connection to the “ground” and electrode holders of welding machines;
– portable electric generators;
– other industrial and household mobile electrical appliances.
There are limitations in the use of the KG electric cable – it cannot be used as a stationary wiring. This is due to the fact that its insulation is very sensitive to mechanical loads. For the same reason, the laying of CG wires in the ground is not allowed. The outer shell can be damaged even as a result of soil pressure.
The exception is air wiring on overhead cables. The open cable line can also be mounted on overpasses, observing all safety measures.
In order for the CG cable used as a welding cable to heat up less, it must be kept more straight, as this reduces its inductance.
Different types of laying can be used for laying these types of cables. Consider the main ways.
To protect the CG cable from various damage to the insulation in open areas of the installation, the method of laying in PVC pipes, metal pipes, ceramic or asbestos-cement is used.
Pipe joints are tight, airtight. Sealed couplings are mounted on the joints. At the exit of the cable pipe it is sealed with resin tape, heat shrinkage, and a special yarn. The diameter of the cable pipes must be 2 times the diameter of the cable.
In trays the KG cable is laid up to 16 mm. This method is used in industrial plants with aggressive environments. Installation of a tray is carried out on surfaces and overlappings of the room. The cables are laid in one layer across the width of the tray.
It is allowed to mount the cable line outdoors on cables and overpasses, if all safety measures are taken. In addition, the cable, as we have said, is frost-resistant, so it can be used even at subzero temperatures.
From other technical characteristics it is also possible to allocate design weight, and external diameter of a cable KG given in the table below:
|Number and nominal cross section of veins, mm2||Nominal outer diameter of the cable, mm||Estimated weight of 1 km / 1 kg of cable|
To ensure reliable operation and protection against electric shock, the grounding is selected depending on the phase cross section. This allows you to protect the wire from high temperatures in the event of an accident.
The ground section must be:
– if the phase with a cross section is less than 16 sq.mm – grounding should be of similar size;
– with a cross-sectional area of the phase from 16 to 35 sq.mm, the cross-section should be 16 sq.mm.
– when crossing more than 35 sq.mm, the minimum cross-section of the ground wire must be at least half of the cross-section of the phase wire.
Thus, to connect an electric stove with a core cross section of 4 sq.mm, the protective wire must have the same diameter. To connect to an electrical cabinet with cores of 50 sq.mm grounding should be from 25 sq.mm.
At the request of the consumer, other cross-sections of the ground wire are allowed. The cross section of the neutral cores, grounding cores, and auxiliary depending on the cross section of the main cores up to 50mm2, are shown below in the table:
|Main core||Zero vein||Grounding ground||Auxiliary vein|
Conductive cores must be twisted from separate copper wires, with a diameter of a single wire, not more than specified in the table:
|Nominal cross section of the vein||The maximum diameter of a single wire|