KG (flexible cable) is a power conductor with a wide range of applications. It is mainly used as electrical wiring or welding cable. The conductor is designed for voltages of 380 V and 660 V. The wire can have several cores - from one to four. The four-core cable includes 1 ground loop and 3 phases.
Application area
KG cables are used to connect mobile mechanisms to electrical networks. They are suitable for indoor and outdoor use. It is not allowed to lay underground, as well as use it as a fixed connection of installations. The wire insulation is not designed for mechanical loads. It can be damaged even from the pressure of hard ground. However, cable laying in pipes is allowed.
If safety measures are observed, laying the conductor in the open air is allowed. It can withstand sub-zero temperatures.
KG wire is often used to connect cranes, submersible pumps and welding machines.
Wire decoding
Cable decoding KG:
- The letters "KG" indicate that the cable is flexible.
- The prefix "H" - non-flammable, with an additional layer of protection.
- "T" - suitable for use in tropical conditions. The minimum ambient temperature must not fall below -10 ºС. In our region, such a cable is practically not found.
- The prefix "HL" means that the conductor can be used even at -60 ºС.
Specifications
The flexible cable KG has some features that make it universal for indoor and outdoor use:
- possibility of use at 100% humidity;
- power cable - flexible, permissible bending radius - at least 8 cable diameters KG;
- recommended for use on devices with high vibration levels.
However, there are also limitations. For example, to connect portable devices, consider the following points:
- maximum voltage in the mains - 660 V;
- when connected to an alternating current network, the maximum oscillation frequency is 400 Hz;
- power consumption should not exceed 630 A;
- when connecting a power KG conductor to an electrical network with direct current, the maximum voltage is 1000 V;
- cable operation should be carried out at an ambient temperature of -50 ... + 70 ºС;
- laying without heating is carried out at a temperature not lower than -15 ºС;
- during long-term performance of work, the core temperature should not exceed +75 ºС.
Subject to the above parameters, the service life of the cable will be 4 years.
It was already noted earlier that the power copper wire KG can consist of four cores.However, there is another parameter that is responsible for the characteristics of the KG cable with respect to the load power - the cross section of the core. Section sizes:
- in a single-core conductor, the cross section can be from 2.5 to 50 mm²;
- two- and three-core cable - cross-section from 1.0 to 150 mm²;
- four-core - from 1.0 to 95 mm²;
- five-core - from 1.0 to 25 mm².
In this case, the core of the ground loop always has a value below the core of the phase. For example, cable KG 3×6+1×4. It is indicated here that the 3 phase wires have a cross-sectional diameter of 6 mm², and the ground is 4 mm². The exceptions are sections 1.0 and 1.5. In such cables, the grounding has a diameter similar to that of the phase.
No less important are temperature indicators that directly affect the life of the conductor. Most KG series cables are used at an ambient temperature of -40…+50 ºС. Some wires may be used under different temperature conditions. They are additionally marked "HL" or "T".
When checking the resistance of the wire, they take as a basis 1 km of the KG welding cable, air temperature +20 ºС, oscillation frequency 50 Hz at a power of 2.5 kW. In this case, the resistance should be 50 mΩ. When checking a single-core cable, it is placed in water. The suitability of the cable is indicated by a temperature indicator of +75 ºС. An elevated setting indicates a problem. This may be the wear of the insulating layer or a break in some cores.
Important! The length of the product depends on the section used:
- a wire with a cross section from 1 to 35 mm² can have a length of not more than 150 m;
- 35-120 mm² - 125 m;
- 150 mm² - 100 m.
Modifications
The KG series consists of several modifications, for example, the KGVV wire.Its peculiarity lies in the fact that it uses insulation not from rubber, but from polyvinyl chloride. This approach allows to increase the service life by up to 25 years. A similar conductor is used for large mechanisms and devices that can operate on both direct and alternating voltage. As an example, we can think of cranes, mining excavators and other mobile equipment.
PVC sheath makes it possible to operate the conductor in a wide temperature range: -50…+50 ºС. This means that the wire is not limited by any parameters regarding climatic conditions.
The KGN cable is another popular modification of the KG series. Its main difference lies in higher oil resistance and incombustibility. In accordance with accepted standards, the abbreviation is deciphered as follows:
- "KG" - cable products have flexible properties;
- "H" - the use of non-combustible rubber as an insulating layer.
The design of the cable consists of a number of basic elements:
- copper conductor corresponding to the 5th class of flexibility;
- a separating layer that does not allow adhesion to the insulation;
- rubber isolation with color marking;
- sheath made of oil-resistant non-flammable rubber.
Cable KG HL is equipped with copper conductors in rubber insulation. This conductor is designed to connect mobile large mechanisms to the mains. Rated voltage at direct current is 1000 V, at alternating current - 600 V. Pulse frequency - 400 Hz. It is allowed to bend the wire at least 8 diameters. The maximum heating temperature of the conductors is +75ºС. If there is a zero core, the letter “H” is added to the marking.
Conductor design:
- Stranded copper conductor class 4 and above.
- separating layer.
- Core insulation. It can have a solid color or longitudinal stripes. Grounding is indicated in yellow-green color, zero - blue. If there is no zero, then blue can be used to color any core, except for the ground loop. The manufacturer can coordinate with the customer the types of core colors.
- Sheath made of hose rubber capable of withstanding low temperatures.
Another modification is the RKGM. The abbreviation stands for the following:
- "P" - rubber;
- "K" - the use of organosilicon insulation;
- "G" - bare wire;
- "M" - copper section.
The section diameter can vary from 0.75 to 120 mm². High flexibility: the turning radius should not be less than two diameters. It is connected to an alternating current network with a frequency of 40 Hz and a voltage of 660 V.
These characteristics allow you to use the conductor to connect various devices and tools. Laying in open areas is allowed, since the insulation is resistant to solar ultraviolet radiation and moisture. At the same time, it should be remembered that there is no protection against aggressive substances and oils.
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