Cable sleeves: characteristics, purpose
When installing a large number of wires used cable sleeves. Such a term is heard by many, but not everyone knows what it is and why it is needed. Meanwhile, this is an important element, the quality of which determines the strength and reliability of cable lines. Of course, in addition to the couplings are used and other devices, but they play a crucial role. This is the topic of this article and will be discussed.
What is a cable box?
According to the definition, the coupling is an electrical product that acts as an intermediate link between the branches of cable ways and electrical appliances or overhead power lines. This is the main task of couplings.
In a different way, cable sleeves are also called electrical fittings, which are perfect for broken wires or for connecting individual parts of a conductor. Thus, the integrity of the cable is restored.
Devices are divided into several types:
- heat shrinkable.
Each of these species performs its own special tasks. It is worth noting that couplings have been produced for the past 40 years. This may indicate that modern devices are comfortable, reliable, durable and meet all standards. In addition, they have the necessary strength resistance to external influences, including ultraviolet radiation, exposure to chemical reagents and so on. Consider these cable couplings in more detail.
Connecting elements are characterized by a wide scope of application. They are almost irreplaceable during the laying of electrical networks, successfully used to connect various kinds of equipment. If necessary, using the coupling, you can connect several conductors into a single circuit.
Often there may be technical difficulties when using a single conductor. In this case, the best option is a coupling. And they are the only correct and possible solution when laying air or underground cable lines, and in the absence of any restrictions.
These elements are not in vain very popular, because the cable coupling provides not only reliable sealing at the joints, but also protects the conductor from mechanical damage. As a rule, such couplings are widely used for laying cable-conductor products having paper or plastic insulating coating.
It is no coincidence that these devices have such a name because they belong to a special class. Their main use consists mainly in connecting a separate cable to a common trunk power line.
This fitting, for example, cable clutch 70-120, in contrast to the connecting elements, is used to connect cables with electrical equipment mainly in the open air.
In turn, the end sleeves are divided into two types, depending on the method of installation: internal and external. The cost of these products will depend on many factors, among which are:
- What material is the coupling made of?
- How complex is the design.
- Type of cable line.
- Insulation sheath cable.
- Operating voltage
In fact, the end sleeve is akin to a conventional cap in the form of a cap. But besides the connection to the power grid, such products are ideal for separating multicore cable when it is needed. Thus, a three-core conductor is often reliably insulated.
Based on the design, cable end clutch can be either single phase or three phase. And the first are used when laying a cable with an operating voltage up to 20-25 kV. As a rule, such conductors are paper insulated, and each core is covered with a metal sheath. Multiphase couplings are relevant for stranded cables.
Heat shrinkable sleeve
Today are the preferred option of all other types of cable fasteners. And all because of the environmental cleanliness of products, reliability and easy installation.
In addition, these products have a distinctive feature - under the influence of a certain temperature, they can shrink.
The strengths of this cable fitting are:
- high reliability;
- elastic construction;
- long service life;
- high level security.
In addition, heat-shrinkable cable sleeves 10 are made of high-tech polymer.It is likely that in some future, due to the merits of heat-shrinkable products, all other electrical fittings made from other materials will completely lose their relevance.
With the start of production of cable clutches, consumers expected some restrictions. Only lead and epoxy couplings could be found on the market, which had significant disadvantages. Take, for example, lead products (SS). Containers are required for their transportation, since the base of the coupling is a pipe made of lead. It is quite plastic, and therefore easily subject to deformation.
As for the service life, the lead clutch with all the components differs in a rather long service life. The only exceptions are videos that are stored for no more than a year. As for epoxy couplings (SEF; KNE; KVEl), here everything depends on the safety of the hardener. If there is no leakage or evaporation, the coupling can last up to 10 years.
On the one hand, it instills great hope, but on the other, these “ifs” only spoil the whole picture. Therefore, heat shrinkable cable sleeves were born. And among all the products is the best option of all existing.However, despite the fact that lead and epoxy couplings are already considered obsolete, they still find applications in cable joints.
The coupling to be installed, regardless of its type, must meet certain requirements. And the main one is high reliability. Thus, each product must have such high rates of:
- moisture resistance;
- mechanical and electrical strength;
- resistance to environmental influences.
Immediately before installing the coupling, the end of the cables are cut.
That is, it is necessary in a sequential order to remove all layers of the outer containment until phase insulating of the core. The size of the cutting depends on the operating voltage, brand and section of the core. These data are usually found in the instructions and references.
When installing cable sleeves, it is necessary to take care of the obligatory grounding with a flexible copper conductor. It is important to choose the right cross-section. If the cross-sectional area of the cores is up to 120 mm, then the cross-section of the grounding conductor should be equal to 16 mm.If the cross section lived a little more - 240 mm, then the copper conductor is taken with a cross section of 25 mm.
The installation of heat-shrinkable sleeves is distinguished by the absence of soldering or bituminous filling, but heating is necessary.