The sleeve of the GML. Connecting sleeves for wires for crimping

Uninterrupted power supply is possible only with a reliable connection of electrical wires. Often, for this purpose, the technology of twisting is used. But the wires connected in this way are prone to overheating and oxidation. Due to the incompatible electrochemical properties of metals, the twisting of aluminum and copper wires is undesirable. In such cases it is recommended to press the sleeves with sleeves.

HML - what is it?

To connect electrical wires from copper by the method of twisting, copper sleeves are used. The abbreviation of GM designates the usual, without any coating, a copper sleeve. HML is a copper sleeve, which has undergone a tinning procedure. A special tin-bismuth layer is applied to it. This is especially necessary for products made of copper, as this material is prone to oxidation.

Due to this coating, the copper tinned copper liners are not susceptible to corrosive processes and do not react with the cores. These products are not recommended for use in electrical work together with aluminum wires. This is explained by the fact that during compression, the protective coating can collapse, and the sleeve of the HML will react chemically with aluminum.

Types of sleeves

Connecting sleeves can be of the following types:

• GA. Under this abbreviation is a sleeve made of aluminum. This type is used to connect exclusively aluminum wires.
• GAM. This is a combined type. Often, such gidzy also called aluminum-copper. Used for butt joints of aluminum and copper wires (build-up in old electrical wiring). Since aluminum has more resistance than copper, in products like GAM, the aluminum part is produced with an increased diameter.
• GSI. Insulated connecting sleeves are tin-coated products that are coated with polyvinyl chloride insulation. They are used for connecting stranded copper wires. During the crimping, the insulation is not removed. The press by means of special mites can be done directly through the coating.

Tubes for connecting power cables

For the installation of cables in instrumentation, electric boards and machine building, cable sleeves are used. They provide good contact during installation and prevent the separation of the cable strands during use.

Cable sleeves have high resistance to deformation and protect the wire from mechanical damage. This significantly extends the service life of the product.

Types of cable sleeves

Depending on the method of installation, the sleeves are intended:

• For crimping. Installation is carried out with the help of cable presses.
• For soldering. Compared with crimping, this method of connection is more laborious.
• For bolting. The work is carried out without using a special tool.

Cross section of the GML sleeve

The dimensions and range of sections are shown in the table. The standard minimum cross section is 1.5 square meters. Mm. Then goes on increasing: 2.5 square meters. Mm, 4-6-10 square meters. Mm. Tubes of copper tin-plated with their parameters correspond to the cross-section of the wire. Professionals-electricians use simplified names: "quartet", "tens", etc. "Six" is called having a 6-millimeter minimum cross-section tinned copper sleeve. GML-6 - this designation can be seen in the technical documentation.

In which cases do you use the "six"?

According to its characteristics, the sleeve of the GML-6 can freely pass through itself four electric wires having a minimum section of 1.5 square meters. Mm. With a cross section of 2.5 square meters. Mm in this case will enter no more than three such wires. The fourth can be used as a sealant. The minimum cross-section of this wire should be 1.5 square meters. Mm. In addition, the "six" can be used for crimping two wires with a cross section of 2.5 square meters. Mm.

The device of sleeves

Depending on the design, the sleeve of the HML can be:

• Through. Such a sleeve is a hollow tube.
• Container in the middle of the tube. This type is used for butt joints. Adjust the depth of approach of the cables to be connected using the data of the GML sleeve. Extended (accreted) wires are recommended to be connected using tubes equipped with partitions.

Product specifications (GOST 23469.3-79)

• Product type - tinned copper sleeve. It is intended for connection by a method of crimping wires and cables made of copper. The product is processed by tin-bismuth tinning. As a result, the sleeve acquires a white shade. It is intended for a voltage not exceeding 10 kV
• The design of the sleeve is through. On the inner and outer diameter, the product corresponds to the tips of GOST 7386.
• HML are designed to connect cables and wires (classes of flexibility 5 and 6). In order to carry out wiring of cores made of copper of grade 2 or 3, you will need a tinned copper sleeve, the size of which can be selected using a special table.

Principle of crimping

A crimping is called a process in which the connection of electrical wires is carried out using special sleeves. The functions of the connecting mechanisms are made by metal tubes (sleeves) into which wires are pierced from both sides.

The principle of crimping is to compress the sleeve with the wires in it using a press clamp. In the home, this special tool can be replaced with pliers or a hammer. Compression is performed in several places. After that, the sleeves are insulated using a shrink tube or an insulating polyvinylchloride tape. This step can be omitted if a ready-made insulated connecting sleeve is used.

Stages

It is not difficult to carry out pressing with sleeves if you follow the step-by-step instructions:

• You need to decide which type of cartridge will be used. The wire material must match the material of the sleeve. Copper connecting means used for cables made of aluminum are undesirable, since their chemical interaction may occur, which will lead to oxidation and reduction of electrical conductivity.
• Treat the inner part of the sleeve using quartz-vaseline pastes.
• Prepare the cores of the cables to be connected. To do this, the insulation is removed from the wires. The length of such a section must correspond to the length of the sleeve. If the crimping procedure is used for shaped wires (their cross-section has an oval or rectangular shape), then these cores should be rounded under the geometry of the connecting sleeve.
• After removing the insulation, the cores must be cleaned. At the end of this stage, the surface of the wire should acquire a metallic luster.
• Treat the cleaned surface of the wire with quartz-vaseline paste.
• Wear the connecting sleeve on the prepared wires. During this work, it is important to ensure that the ends of the connected wires are docked to each other at the center of the sleeve.
• Carry out pressing. The work is carried out by the reciprocating movement of the upper handle of a special press. The action should be performed until the matrices are in full contact. It is important that the working area of the mites corresponds to the size of the sleeve.
• Insulate the connection point. To do this, you can use electrical tape. Also, the shrink tube will handle this task . In this case, the connected wires are passed through it at the very beginning of work. It is easy to use a construction hair dryer.

In which cases is the crimping method used?

This technology using HML can be used:

• For connecting wires in a line with a high load.
• When connecting wires with a large cross section.
• In cases, if it is impossible to apply some other type of connection.

The most common mistakes during pressing

Often some masters, not having at hand special mites for crimping, use standard pliers, chisel and a hammer for crimping. This is not recommended, since the tongs are equipped with special matrices, punches and sponges, which ensure high-quality crimping. Often, the wires connected in a tinned copper sleeve with the help of pliers, after a while from it drop out. Today in the market of tools a wide range of manual or electric crimping presses-ticks is offered .

If there is no copper tin-plated connecting sleeve of the required size, a copper tube may be used. The remaining free space between the living space and the wall of the copper tube of the master is filled with pieces of other veins. It is important that these pieces are of the same metal as the tube. This requirement is applied to both copper tubes and aluminum ones. However, there is a big difference between the electrical material in this sleeve and the material in a homemade tube made from a tube. Therefore, for the crimping, it is best to purchase a connecting means made of a special grade of metal. In the case of HML, this will be electrical copper.

Often, having bought a GML with an inappropriate cross-section, some consumers cut off part of the conductor. This is mainly the case when the cross-section of a copper tinned thermowell is smaller than that of a vein. Cut is not recommended, because a reduced cross-section in the wire will create a mechanically vulnerable place on it, in which a breakdown can occur.

After an unsuccessfully selected too large a GML during the connection of multiwire wires, they can not be doubled and shoved into the sleeve. The joint will not give this mechanical strength. Contact will remain unreliable. To connect the wires by pressing it is not necessary to use a soldering iron or welding machine. For work, only special tongs will be needed. They are easy to work in the most inaccessible places. Copper tin-plated cartridges, as well as similar products of other types, have become increasingly popular lately.