Sleeves for crimping wires, which ones to choose and how to crimp

Crimping a wire cable is a very responsible task, especially if this connection is a power connection. In this article we will look at how to correctly terminate connections of low-current wires (up to 15–20 amperes).

Remember! The use of power cables and lugs made of the wrong material and cross-section can lead to serious consequences, such as fire of the wiring, for example.

Crimping technology

There are two methods by which crimping is carried out:

• local indentation;
• complete compression.

The wire for crimping is copper or aluminum. Therefore, the sleeve can be either copper or aluminum. There is also copper-aluminium. Since an aluminum cable is prone to the formation of an oxidizing film, the aluminum sleeve must be cleanable and treated with a special lubricant. To protect aluminum from oxides, quartz vaseline paste is used. Copper wire is also subject to lubricant treatment. With its help, the likelihood of damage to the core during crimping is reduced and friction is reduced.

If the cores are multi-wire, they are aligned and folded so that they easily fit into the sleeve; you can twist the wires a little. Then the cable is inserted into the cartridge until it stops. The connection can be made not end-to-end, but, for example, with a factory. Then the total cross-section of all wires should not exceed the cross-section of the bushing.

In any case, sleeves are used that are designed for the total cross-section of the cores being crimped. If a press with point (local) indentation is used, make 2-3 pressings evenly distributed along the length of the sleeve to ensure mechanical strength of the connection and good electrical contact. For continuous crimping using hexagonal or square dies, the recommendations are essentially the same

In both cases, it is important that the sleeve does not crack during crimping (if it is too small) and that there are no uncompressed areas or cavities (if it is too large)

After the crimping has been carried out, it is necessary to create an outer insulating layer at the junction using electrical tape or elbow cloth. After insulation, you should carefully fold the wires and the cable itself in the junction box.

The video below clearly shows how to crimp wires with press pliers:

Marking and decoding

The industry produces a large number of all kinds of tips, which differ in design and materials.

Color coding option

There is a special marking system that allows you to distinguish the material and use it for its intended purpose. Here is a breakdown of some of the symbols:

• A – the sleeve is made of aluminum;
• L – brass is used;
• M – the base of the product is copper;
• T – the element is made of tubular metal;
• U – the connector is made in the shape of an angle.

There is also a designation in the form of the letter O, which indicates the presence of an inspection window through which you can make sure that the cables are correctly located in the sleeve inside.

If the marking is TML (O), then it means tinned tubular copper with an inspection window. NSHVI - means a pin sleeve tip, and NKI - a ring one. In this case, the numbers indicate the cross-sectional area or diameters of the rod. To make it easier to find suitable connectors, for example, NShVI or KVT, you can use a special catalog or tables.

After the letter designations in the markings there are usually numbers that contain information about:

1. nominal section;
2. diameter of the contact rod;
3. internal diameter of the shank.

For example, the product is marked TML (O). This means that this wire termination is made of copper tubing and is tinned. Its distinctive feature is the presence of a small hole - an inspection window, with which you can verify whether the wire is inserted correctly for crimping.

Such contacts are used mainly in production, so not all electricians are aware of their existence.

How to connect electrical wires with lugs

Another way is to use tips. The tip looks like a piece of tube, cut and turned flat on one side. A hole for a bolt is drilled in the flat part. The lugs allow you to connect cables of any diameter in any combination. If it is necessary to connect a copper cable to an aluminum cable, special lugs are used, in which one part is copper and the other is aluminum. It is also possible to place a washer, brass or tinned copper, between the tips.

The ferrule is pressed onto the cable using a crimper, similar to how wires are connected using crimping.

Features of the tool for crimping electrical wires

Crimping of wire lugs is carried out with a special tool. It is selected for the specific type of product being clamped. After all, it can not only be flat, but also have the shape:

• cylinder;
• forks;
• loops;
• knife,
• plug.

Tips are available in different shapes Source elektroznatok.ru
When choosing a tool, the crimping range is also taken into account. This is a parameter that shows the largest and smallest cross-section of the electrical cable. If a wire with a diameter of 0.25-16 mm is crimped, then crimping is done using hand pliers. Such a tool is used, for example, during the installation of low-current, telephone, and computer lines.

Hydraulic pliers are used when connecting substations when large-diameter cables are laid. Their cross-sectional area usually exceeds 16 mm². If a large amount of work is being done, professional electricians use electric pliers. They can operate in semi-automatic or fully automatic mode.

Hydraulic powerful press jaws Source avtomag96.ru

How to brew twist

For good contact, the twist can be welded with a graphite electrode or a gas torch. Torch welding has not become widespread due to the complexity and the need to use gas and oxygen cylinders, so this article only talks about electric welding.

Electric welding is performed using a graphite or carbon electrode. Graphite electrode is preferable. It is cheaper and provides better welding quality. Instead of a purchased electrode, you can use a rod from a battery or a brush from an electric motor. It is better not to use copper electrodes. They often get stuck.

For welding, you first need to make a twist 100 mm long, so that the finished one turns out to be about 50. The protruding wires need to be trimmed. For welding, it is best to use an inverter welding machine with adjustable current. If this is not the case, then you can take a regular transformer with a power of at least 600 W and a voltage of 12–24 V.

Near the insulation, “ground” or “minus” is connected using a thick copper clamp. If you simply wrap a wire around a twist, the twist will overheat and melt the insulation.

Before starting welding, it is necessary to select the current. The required current varies depending on the number and thickness of the wire that makes up the twist. The welding duration should be no more than 2 seconds. If necessary, welding can be repeated. If everything was done correctly, then a neat ball will appear at the end of the twist, soldered to all the wires.

Subtleties of the process

Regardless of how and what you use to weld stainless steel, you must follow the following rules that will help you obtain a high-quality connection:

1. Prepare in advance the liquid that you will use to cool the surface upon completion of the work.
2. Ampere characteristics should be 20% lower compared to welding other types of steel.
3. During the joining process, control the gap size due to the high linear expansion of the alloy.
4. The length of the electrodes used should not exceed 350 mm, due to the high resistance of stainless steel.

If you neglect even one point, the risk of a weld defect will be very high.

Tip sizes, design features

The minimum available sections for GML are 1.5 mm 2. Further sizes increase - 2, 4, 6, 10 mm 2 and higher. Based on these values, we can say that the cross-sections of the sleeves are equal to those of wires and cables. It is quite easy to decipher the tip designations. For example, GML-6 is a copper tip, tinned. The cross-section is 6 mm 2. In the case of combined sleeves, the marking indicates two sizes - for aluminum wire and for copper. For example, GAM 16/10 - 16 for aluminum, and 10 for copper.

By design, the sleeves can be end-to-end in the form of a hollow tube or with a partition. The latter are used when crimping wires with end-to-end lugs is performed. These partitions are located in the middle of the sleeve. With their help you can adjust the depth of the cable entry. If it is necessary to extend it, then both ends will go into the tip to the same length.

Ferrule crimping

To find out which tool is best to use for crimping various types of tips, watch this video:

As you can see, you don’t need any special intelligence or experience to use the tips; everything is done easily and quickly. The only thing you will need are special devices - a stripper and press pliers, but they are affordable and can be purchased. When connecting multi-core conductors, be sure to use lugs and make the power supply as reliable and safe as possible.

How to crimp a wire: instructions for single and double NShVI

The wire with the tip must be installed in press jaws in a matrix of a suitable size. During the crimping process, you need to ensure that the wire does not move inside the sleeve. The first crimp is done with an indentation of 1–2 mm from the edge, if necessary, the second at the same distance from the first.

The handle of the press pliers is compressed until it is in full contact with the surface of the part and the matrix is ​​connected, then the sleeve is moved and a second crimping is done. If the shank is long, work continues until the colored skirt.

The crimping scheme for a double tip is practically the same. You only need to insert two wires into one hole in the shank at the same time.

Stages of wire crimping

Visual instructions for crimping a wire with an NShVI lug are presented in the video:

Crimping power cable lugs

When crimping power cables, tinned copper lugs are used, which are well protected from corrosion. If, when cutting the cable, its cores “fluff” significantly and become larger in diameter than the rest, then perform the work on a sharpener. When unrolling the cable, make sure that the circle removes excess knots along the cores and does not bend them.

Soldering is absolutely not suitable for crimping a power cable, since single tin contacts cannot be used on such wires.

Principle of wire crimping

You can perform crimping of wires using sleeves in several ways. It will not be possible to single out the best of them, since comparison is inappropriate here. The choice of crimping method directly depends on the conditions for electrical installation work, cross-sectional parameters and other important points. Let's consider the features of the main method of crimping using sleeves.

Work begins by introducing the previously stripped ends of the wires into the cavity of the sleeve. The next step is crimping - squeezing using a special tool. The metal surface of the cores and sleeve is compressed, resulting in a reliable adhesion of the parts. It is necessary to connect at several points, followed by insulation of the connection points. An exception is working with insulated sleeves for crimping, which do not require additional insulation.

When choosing this method of connecting wires, you need to remember that the contact will not be disconnected in the future. Taking this into account, work will need to be carried out carefully and prudently.

What it is

Crimping is a method of connecting conductors that involves the use of special conductor sleeves. The sleeves themselves are similar in appearance to ordinary metal tubes that act as a passive connecting mechanism.

Example of pressed wires

The cable cores that are to be connected are inserted into the tube from different ends, and then compressed with special press pliers. The end result is a reliable and even contact, forming a so-called electrical unit. The sleeve is compressed in two or more places depending on the type of wires, the cross-sectional area of ​​their cores and the length of the tube itself. During compression, both the sleeve and the cores are deformed, and this, in turn, compresses the conductive surfaces. The result is strong and reliable electrical contact between two conductors.

Important! The connection point is usually insulated with a thermally insulating tube or polyvinyl chloride electrical tape. Crimper with insulating handles

Crimper with insulating handles

The main points of the process of crimping wires and twists

To do this, you will need to strip the wire from the outer insulation, and then use a mounting knife to remove the inner protective sheath. To make it convenient to twist the wires, I personally collect the bare wires into a bundle and bend the ends.

Then, first twisting the wires by hand, I achieve greater contact through the work of the pliers with which I tighten the twist.

Having bitten off the excess wires with the same tool, I get a good connection 3-5 cm long.

Next, the only thing left to do is put copper sleeves of suitable sizes on the twists and crimp them. Moreover, crimps come in different diameters (6 mm, 8 mm, 10 mm and more). Usually, I use 6 mm products to connect strands of light groups, where the cross-section of the wires is not so large (1.5 sq. mm). For socket groups, sleeves with a diameter of 8 mm or more are taken, since here the wires have a cross-section from 2.5 to 4 sq. mm.

After that, I insulate the connections, put them in the junction box and close the lid so that everything is “feng shui”.

Video description

The use of crimping pliers and strippers is described and shown in this video:

On a note! A wide range of tools allows you to purchase a suitable crimp for wires in accordance with their diameter, the lugs used, and the planned amount of work.

Although the most common are press pliers, the operating principle of which is similar to the functioning of pliers, electricians also use a diaphragm tool in their work. Its special feature is the ability to perform crimping on 4 or even 6 sides. The exact number of such surfaces is influenced by the type of diaphragm that is installed in the jaws.

The full-circle tool sleeve increases the reliability of the connection. Crimping of cable lugs is performed with maximum density. In addition, there is no need for the tool to change the bushing because the tool is able to automatically adjust to its thickness.

Diaphragm tool Source ls-market.ru

However, there is a drawback to diaphragm clamps. Using such a tool, crimping is performed exclusively on the end of one cable. The reason for this is the presence of a closed head located on the other side of the hole into which the tip is inserted. Therefore, such a tool is not used to crimp 2 electrical cables. In other words, it is not used instead of twisting.

Common mistakes when crimping

Cutting shells

At first glance, they are long. People who do not have the necessary knowledge and experience believe that using the entire cartridge case is wasteful, and cut it into pieces. This leads to a reduction in the length of the section where the conductors are bonded. The result is that the mechanical strength of the contact suffers, since working with pliers becomes inconvenient, and the number of pressure points decreases.

Wrong choice of sleeve diameter

If it is larger than required, then it is unlikely that it will be possible to produce high-quality crimping. The only way out is to bend the tip of the wire and then insert it into the sleeve. But such crimping is only suitable for “copper”, but the strength of the connection becomes lower. Aluminum wire breaks easily, so it is not an option.

With a smaller sleeve diameter, people without experience try to “plant” the ends of the wires into it by sharpening them a little. This is absolutely forbidden to do! Reducing the cross-section in a particular area leads to overheating and destruction of the metal. By the way, this often causes inflammation. It remains to add that the contact strength also decreases.

Crimping with pliers

Press jaws are specially designed for this specific job. Crimping with pliers is fraught with the fact that the conductor is deformed, and quite significant. After all, with this connection method it is impossible to control the clamping force. The consequences of reducing the cross-section of the core are indicated above.

Some craftsmen do crimping exactly this way, while assuring that everything is “acceptable.” But this does not mean that this technique is correct. The author came across such a situation and asked the unfortunate master a question: if he needs to do crimping at home, will he also work with pliers? As expected, there was no clear answer.

Useful tips

• It is not always possible to select a sleeve so that after placing the ends of the conductors in it, there are no voids left. The more free space, the higher the risk of poor contact after crimping it. How to proceed? The easiest way out of the situation is to cut pieces of wire (bare) with a length slightly shorter than that of the sleeve, and “hammer” them into it. Such artificial compaction will significantly improve the quality of crimping.
• If the connection of wires is made to extend the line, then their joint should be located in the center of the sleeve.

• When insulating the joint, the tape (tube) must extend beyond the sleeve cuts by at least 10 mm.
• In the case when at least one of the wires is multi-core, or different numbers of them are spliced ​​on both sides, not metal sleeves are used for crimping, but insulated lugs (NSHVI).

It turns out that there is nothing complicated about crimping with sleeves. The main thing is to choose the right size. If the reader takes into account the recommendations given, then it is quite possible to cope with such work on your own. Good luck!

Recommendations for crimp testing

If difficulties arise in selecting a sleeve that is ideally suited for the wires in size, it is better to opt for a tube slightly larger than required. In this case, the void can be filled by cutting bare wire with a slightly shorter length than the sleeve. Compaction in this way will improve the quality of the crimp.

Extending the wire using crimping should imply that the connection joint is located exactly in the center of the tube.

When isolating the joint, the connecting tape must extend beyond the edges of the sleeve by at least 10 mm. If multi-core wires are connected to each other or it is necessary to splice different numbers of them on both sides, then the correct solution would be insulated type connecting sleeves.

In conclusion, we note that crimping as a process is not difficult if you act consistently, use a special tool and suitable sleeves. One way or another, you need to remember that we are talking about a permanent connection, so you will need a wiring diagram. Having a plan at hand will help you avoid mistakes during the work.

Connection Features

The technology involves two options for crimping. This is a method of local indentation and continuous compression. Copper or aluminum wires are used for work. The sleeve must also be made of these materials. There are also elements made of copper-aluminum alloy.

Since aluminum cables are prone to the appearance of oxidative films on them, the sleeve must first be cleaned and treated with special lubricants. Copper wires are also pre-treated. The use of lubricants in the process reduces the risk of possible damage to the cores. The friction force is also noticeably reduced. Pressure testing is carried out using manual or hydraulic tools. In the latter case - with a figure press. It is usually used in large industries.

How it works? The two ends of the cable are crimped until they take a round shape. Next, the core is inserted into the sleeve until it stops. It is possible to connect not exactly end-to-end. But in this case, the cross-section of all cores does not exceed the bushing. In the case of local compression, contact directly depends on the depth of the pits. The latter can be measured with a caliper. If continuous compression is used, then check the cross-sectional area. Then, when the crimping of the wires is completed successfully, it is necessary to treat the outer layer with electrical tape or elbow cloth. Next, the wire and cable are carefully laid in the junction box.

Main types and varieties of ticks

Structurally, crimping pliers can be divided into two main types - diaphragm pliers and those that work on the principle of pliers.

The second option is considered more common: when you press the handles, the tool compresses the bushing with two working planes, but, unlike pliers, there are cutouts of the desired shape on the edges, which serve as guides. This device is suitable for crimping U-shaped lugs.

The main advantage of the tool is its versatility, since the tips can be crimped from any side. The versatility ends when it comes to liner sizes: specific press jaws are designed for a small dimensional range of sleeves.

If you crimp frequently or are currently working on a large wiring project, you are more likely to crimp wires with both large and small sizes of cable lugs. Thus, you need to keep several crimpers on hand for different bushings.

There is an excellent alternative: crimpers with a set of removable dies installed on a cassette. To change, the working part of the tool is inserted into the hole in the cassette, then pulled towards you, and the matrix is ​​inside. All that remains is to insert the base into the hole with the matrix of the desired shape. Remember high-quality razors with removable blades - a similar principle works.

As for diaphragm press pliers, they allow crimping from four or six sides. The exact amount depends on the diaphragm mechanism. The full circumference of the sleeve improves the quality of the connection and ensures maximum crimp density. In addition, this device automatically adjusts to the thickness of the sleeve used, so there is no need to change dies.

But even such a tool has a drawback - you can crimp the end of one wire, since there is a closed “working head” on the other side. Using diaphragm pliers, you cannot crimp two wires instead of twisting them.

Types of connecting tubes

Crimping of wires can be carried out using connecting sleeves in several designs. The choice of connecting tube will depend on the electrochemical properties of the metal from which it is made and its interaction with the material of the wire.

There are several options for materials for the manufacture of sleeves:

• copper;
• tinned;
• combined universal;
• isolated.

Copper tubes (CM) are used for copper wires, the crimping of which cannot damage the protective layer due to its absence. The tubes cannot be used in aggressive environments.

Tinned sleeves (GML) are suitable for copper type cables used in aggressive conditions. The white protective layer covering the surface of the product fully copes with the main functions. The tubes are not suitable for working with aluminum wires due to possible contact of the protective layer, which is partially destroyed during compression, with aluminum.

Combined wire sleeves have a distinctive feature - their shape. The aluminum part is larger than the copper part. This is due to the resistance of aluminum, which exceeds the resistance of copper. During the crimping process using such tubes, wires are inserted on each side, taking into account the type of metal.

The last option for sleeves is insulated (GSI). They replace additional insulation with PVC tapes due to the presence of heat-shrinkable tubing. Their structure is similar to the structure of GML tubes, with the exception of a PVC layer that does not transmit electricity. The protective layer is quite plastic and reliable, indestructible even during the crimping process, taking the shape of a metal.

What does the tip marking mean: full explanation

Each type and type of product has its own alphanumeric marking, without knowing which it is impossible for a home craftsman to explain in the store what he needs. Let's look at popular markings:

• TML is a tin-plated tip, to work with which you need a special tool - a crimper. Looks like NSP. The only difference is that NShP is copper;
• TA – the same tip, but made of aluminum;
• SIP is a self-supporting tip that has its own insulation along the tube and an annular mounting plate;
• NSHVI - common in household use, sleeve pin;
• NKB - used in industry as geophysical cable;
• RFI-M is already a flag tip;
• IEK – copper fork;
• TMD – double blind connectors;
• NKI - isolated ring.

Aluminum products are regulated by GOST-9581-80, copper - GOST-7368-80.

Products for crimping are made of copper, aluminum or bimetal

What is the essence of the method?

Crimping is a method of connecting wires using special sleeves. Outwardly, they look like ordinary tubes and serve as a connecting mechanism.

The wire strands that are to be connected are inserted into the tube from two opposite ends, crimped with press pliers, and as a result, a strong and reliable electrical unit is obtained. The tube is compressed in two or three places, depending on its length and the cross-section of the switched conductors. The connected cores and the sleeve are jointly subjected to deformation. At this moment, the tube compresses and squeezes the conductive surfaces of the conductors. Due to this, the wires interlock with each other, which provides reliable electrical contact.

The junction is then isolated.

Most often, this method is used in situations where it is not possible to use another type of connection. For example, welding requires the presence of electricity so that the welding machine can be connected. When working in a small junction box, it is inconvenient to position the bolt connection, nut clamp or terminal block. And reaching up to the distribution box from the ceiling with a soldering iron is also not very convenient. It is in such cases that crimping wires using sleeves helps out.

The crimping method is most in demand:

• if it is necessary to connect wires in power lines with a high current load;
• for switching multi-core conductors;
• if it is necessary to connect large cross-section wires.

This is interesting: How to choose a cable channel for electrical wiring: let's look carefully

Advantages and disadvantages

There are many positive aspects to crimping:

1. The tool used to make this connection is hand-held and does not require electricity to operate. In cases where you have to work in a room where there is no voltage, crimping is the only high-quality connection method.
2. Using crimping tubes, you can connect conductors from different metals, which is a solution to the eternal problem of switching copper and aluminum conductors in one electrical unit.
3. If welding requires a specialist capable of performing welding work, and when soldering it is necessary to be able to use a soldering iron, then anyone can do crimping; you just need to try the press pliers in action once.
4. Using a special crimping tool, it is possible to make connections in any, even limited spaces. It is especially convenient when connecting wires in a socket box or box.
5. Crimping with press pliers and sleeves allows you to shorten the connected sections of wires to a minimum.
6. Due to mechanical force, the most durable contact connection is created.
7. As a result of crimping, a permanent connection is obtained that can withstand heavy physical stress when breaking.
8. Installation speed is minimal, connection quality is maximum.
9. This contact does not require any maintenance.

The one-piece type of crimping is in some way a disadvantage, that is, if necessary, it is impossible to unscrew the connection and replace one of the conductors. The sleeve can only be cut out.

Twist connection

The easiest way to connect wires is twisting. Previously, this was the most common method, especially when wiring in a residential building. Now, according to the PUE, connecting wires in this way is prohibited. The twist must be soldered, welded or crimped. However, these methods of connecting wires begin with twisting.

In order to perform high-quality twisting, the connected wires must be cleared of insulation to the required length. It ranges from 5 mm when connecting wires for headphones to 50 mm if it is necessary to connect wires with a cross-section of 2.5 mm². Thicker wires are usually not twisted together due to their high rigidity.

The wires are stripped with a sharp knife, insulation stripping pliers (ISR) or, after heating with a soldering iron or lighter, the insulation is easily removed with pliers or side cutters. For better contact, bare areas are cleaned with sandpaper. If the twist is supposed to be soldered, then it is better to tin the wires. Wires are tinned only with rosin and similar fluxes. This cannot be done with acid - it corrodes the wire and it begins to break at the soldering site. Even washing the soldering area in a soda solution doesn’t help. Acid vapors penetrate under the insulation and destroy the metal.

The stripped ends are folded parallel into one bundle. The ends are aligned together, the isolated part is held firmly with your hand, and the entire bundle is twisted with pliers. After this, the twist is soldered or welded.

If there is a need to connect the wires to increase the total length, then they are folded opposite each other. The cleaned areas are placed crosswise on top of each other, twisted together by hand and tightened tightly with two pliers.

You can only twist wire made of the same metal (copper with copper, and aluminum with aluminum) and of the same cross-section. Twisting wires of different sections will turn out uneven and will not provide good contact and mechanical strength. Even if it is soldered or crimped, these types of wire connections will not ensure good contact.

How to choose the right crimp sleeve by diameter

Crimping sleeves can be used equally successfully to make a high-quality connection of both single-core and multi-core electrical or network cables. When choosing such a sleeve for a mono- or multi-core, you should take into account not only the material of manufacture, but also the diameter of the connected conductors. To correctly select crimp sleeves according to the diameter of the wires being connected, it is best to use special reference tables.

Technical dimensions of the sleeve for crimping wires, taken into account during selection

Table 1. Parameters of GM sleeves and recommended tools for crimping

The quality of the electrical contact created directly depends on how correctly the crimp tubes are selected according to the diameter of the wires being connected. So, if the diameter of the wires that need to be connected is greater than the inner diameter of the sleeve itself, then the conductor cannot be placed in the inner part of the tube. Situations where the inner diameter of the sleeve is much larger than the outer diameter of the wires being connected are also undesirable. In such cases, the crimped wires, located in the inner part of the tube with a significant gap, will create a poor-quality contact.

Table 2. How many wires fit in one connector

It is also possible to qualitatively connect wires using a sleeve, the internal diameter of which significantly exceeds the cross-sectional size of the conductor itself. To do this, they use a simple technique: the wire is inserted into the sleeve, after which the gap that has formed between the walls of the connecting tube and the surface of the conductor is tightly clogged with pieces of strands from a wire made of the same metal. After performing this procedure, the sleeve is crimped using standard technology.

What you need to know about the sizes and design features of tubes

Sleeves for connecting wires are divided not only by the type of material from which they are made, but also by size and range of sections. The minimum cross-section is 1.5 m. This applies to GML type tubes. Further indicators are growing. It is worth remembering that the tubes are produced with a cross-section similar to the cross-section of the wires.

A separate point is the design of the products. The tubes can be through and with a partition located in the center. Partitions are needed to control the depth of the wire entry when extending from two sides, joint to joint.

Section of sleeves of smaller diameter

A very stupid mistake, which is often made out of ignorance or out of a desire to save money (buy a cheaper connecting cable sleeve). If the cross-section of the sleeve is smaller than the cross-section of the wire, then in this case they can grind the wire, reducing its diameter so that it fits. But this leads to an increase in resistance in this area, reduces throughput and degrades strength. Ultimately, this will lead to destruction of the wire in the place where its cross-section was reduced.

Larger diameter sleeves

And this happens when people buy by eye. In this case, it will not be possible to make the connection reliable; the greater the difference, the less reliable it will be. Of course, there is a method in which the ends of the wires or cables are bent in half and driven into the sleeve, but this is not always possible (the difference in diameter must be very large), and this also will not ensure reliable contact.

To summarize the previous two points, the connecting sleeves must be selected strictly for the cross-section of wires and cables. There will be no difficulty with this, today everything is standardized, all meanings can be found on sale. It is simply impossible to imagine a situation where it is not possible to buy a connecting sleeve of a suitable diameter.

Standard crimping errors

There are several typical mistakes that novice electricians or those who carry out the core crimping process themselves make. For example:

1. The used sleeve has a cross-section smaller than the wire. There is never any need to reduce the cross-section of the cores and adjust it to the diameter of the sleeve. This leads to an increase in resistance and a decrease in throughput. Where there was a combination, the vein will heat up and collapse.
2. Large size sleeve. If the socket is used with a large diameter, it will not bring a strong and reliable connection. Even if you bend the wire several times, this will not lead to good performance, since the mechanical strength will drop by almost half.
3. Cutting the sleeve into several parts. When crimping a cable with a short length of exposed ends, it is inconvenient to work with pliers, and the contact area is reduced.
4. Crimping should be carried out exclusively using press jaws. Special tools were invented for this joining method. Therefore, you should not use pliers or a hammer, as this can damage both the sleeve and the cable. To prevent this from happening, it is necessary to use a tool such as press pliers, as they greatly simplify the work of crimping cable connections.

That's all I wanted to tell you about how wires are crimped with sleeves. We hope the information provided was useful and interesting for you!

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Basic Rules

Connecting wires by crimping is not particularly difficult. You just need to know and take into account a few important rules:

1. The metals from which the sleeve and the connected conductors are made must correspond to each other.
2. Many electricians shorten the factory sleeves and simply saw off the excess part using a hacksaw. This is undesirable, as the reliability of the contact connection decreases.
3. Crimping of wires with sleeves should only be done using a special tool - press pliers. There is no need to use a hammer or pliers, as there is a possibility of damaging both the sleeve and the conductor being crimped.
4. The sleeve should be selected with an internal diameter such that it is as close as possible to the diameter of the wire being crimped.

A very common mistake is when they try to reduce the cross-section of the conductor in order to adjust it to the size of the tube. For example, if there is a sleeve with a smaller diameter, some people want to cheat and remove several strands from a stranded wire. Never do this, because the resistance will increase, the throughput will decrease, which will lead to heating and destruction of the contact connection.

Wire crimping: common mistakes

Many novice electricians or people who do not have information in the field of electrical installation often make a number of mistakes that affect the subsequent operation of the entire electrical circuit.

Pressure testing can be carried out using sleeves or tips

Installation errors:

• The sleeve cross-section is smaller than the cable cross-section;
• Sleeve of larger cross-section;
• Saving;
• Crimping without using pliers.

When purchasing crimps (sleeves), many do not take into account such an important factor as the cable cross-section. Therefore, after purchasing a crimp sleeve or sleeves, it turns out that its cross-section is smaller than the cross-section of the wire.

The main mistake that is made in this case is reducing the cross-sectional area of ​​the cable, which is completely unacceptable. This is due to the fact that at the junction of the wires, resistance increases, which leads to heating of the wires during operation. And if a device with higher power is connected to this network, the wire may simply burn out and lead to a short circuit.

The use of sleeves with a large cross-section will not allow achieving high-quality and reliable contact

It is important to understand that with this connection, the mechanical strength also decreases

In order to save on connecting elements, many divide one sleeve into several parts, thereby increasing the resistance accordingly.

The rules stipulate that crimping of sleeves must be done only with a special tool in the form of press pliers. Therefore, a hammer or pliers are completely unsuitable for this job.

This is due to the fact that using a hammer can damage the sleeve, and compressing the sleeve with pliers is not enough for good contact.

Additional recommendations

For proper crimping, you must use the following tips:

1. Make the junction of the conductors in the center of the connecting tube.
2. Select the correct sleeve section. There will be fewer voids inside the clutch, and contact will become more reliable.
3. Apply the insulation so that it extends 1 cm beyond the connecting tube on both sides.
4. Use ferrules if cables with different numbers of cores are spliced.

Crimping is a procedure that allows you to obtain maximum adhesion of conductors when installing electrical networks. However, to carry it out correctly, the appropriate tools and materials are required.

Classification by material of manufacture

One of the main parameters, depending on which wire sleeves are divided into different types, is the material of their manufacture. The need to use dissimilar sleeves is determined by differences in the electrochemical properties of the connected wires made of different metals. So, if an inappropriate sleeve is chosen to connect wires made of a certain metal, the place of the formed contact will oxidize, which over time will lead to a decrease in its reliability in terms of electrical conductivity.

The main types of sleeves for crimping electrical wires, depending on the material from which such tubes are made, are:

• copper sleeves;
• tinned connecting sleeves;
• combined;
• isolated.

Copper

A copper sleeve, which is marked GM, is needed for crimping wires also made of copper. Taking into account the fact that the copper sleeve does not have a protective coating, it can only be used to connect wires operated in a non-aggressive environment. If you neglect this requirement, the copper sleeve will quickly oxidize and cease to perform its functions.

Copper cable sleeves must be made from copper tubes of grades M1 or M2

Tinned

To connect electrical wires operated in an aggressive environment, tinned copper sleeves for crimping are used, which are marked GML. In order to protect the main material of their manufacture - copper - from electrochemical corrosion, GML sleeves are coated with a special compound.

This is explained by the fact that part of the protective coating of such a tube is destroyed when it is compressed, which will lead to contact between aluminum and copper and, accordingly, to the development of electrochemical corrosion.

Connecting sleeves type GML, made of electrical copper with a tin-bismuth protective coating

Combined

Quite often, when installing electrical networks, it becomes necessary to connect wires whose cores are made of different metals. To solve such problems, combined type sleeves have been specially developed and are successfully used. The design feature of such crimp tubes, which are marked GAM, is that one half of them is an aluminum connecting sleeve, and the second is made of copper. At the junction of two such tubes, which are connected to each other by welding, there is a special limiter. It is necessary in order to prevent contact of two dissimilar wires inside the sleeve itself.

Adapter cable sleeve aluminum-copper 16/10 sq. mm

Another design feature of combined crimp tubes is that the part of them, which is the aluminum connecting sleeve, has a larger diameter than the tube intended for copper cables. This design feature is explained by the fact that aluminum, when compared with copper, has greater electrical resistance, therefore the wire made from it, which will be connected to the same electrical network with a copper conductor, must have a larger diameter.

The crimping itself using combined sleeve clamps is performed according to the same algorithm as the procedure with sleeves of any other type. However, it is necessary to carefully ensure that dissimilar wires are inserted into a tube of the appropriate metal.

Isolated

Among the crimping tubes used for crimping electrical wires, the category of insulated connecting sleeves is distinguished. The use of the latter eliminates the need to perform additional insulation of the contact area formed with their help. In terms of their design, insulated sleeves are the same tinned copper tubes, the outer surface of which is covered with an insulating layer of fairly durable and at the same time plastic PVC. Due to the mechanical properties of such a protective layer, sleeves of this type can be successfully crimped without compromising their original characteristics.

Fully insulated connection sleeves

Insulated sleeves for hermetically sealed connection of SIP wire cores

Types of sleeves

It is very important to choose the right sleeves for crimping wires.

According to the material of execution

A copper cable or wire should be crimped with copper sleeves accordingly. They come in two types and have the following abbreviation:

• GM - copper sleeves. They are made purely of copper, do not have any coating or processing, and in appearance they look like ordinary pieces of copper pipes.
• GML – tinned copper sleeves. They undergo a tinning procedure, that is, their surface is treated with a special tin-bismuth layer. This is done in order to prevent oxidation and corrosion processes. It is also known from school physics lessons that copper, like any other metal, oxidizes. Tinning prevents this process; the crimped wires will not enter into a chemical reaction with the tinned sleeve.

I would like to give one useful piece of advice. Do not listen if suddenly one of the experienced electricians tries to prove to you that using GML sleeves it is possible to crimp aluminum wires, since the tin layer will not allow direct contact of aluminum with copper. This is incorrect, because during crimping the surface layer of the tube is deformed and the corrosion process is still inevitable.

To connect aluminum wires, they use products made of the same metal; they are designated GA (aluminum sleeve).

There are also combined sleeves, they are designated GAM (aluminum-copper sleeve), in everyday life many call them aluminum-copper. This option is used when you need to connect wires made of different metals end to end. The sleeve is a tube of two parts; at the junction of dissimilar metals, the connection is made by friction welding. Here everything is extremely simple and clear - you need to insert copper wires into the part of the tube made of copper, and an aluminum conductor into the aluminum part.

And the most modern version with the designation GSI (insulated connecting sleeves). They are based on ordinary tinned tubes, only they are covered with polyvinyl chloride insulation on top. They crimp copper wires. During crimping, the insulating layer is not removed, pliers are put on top of it, and compression is performed. Such sleeves greatly simplify the work of an electrician, since the crimped electrical assembly no longer requires any additional measures to insulate it.

By size

After the letter designations, a number is written on the sleeve. What does it mean? This is the cross-section of the conductor for which this product is designed. For example, tinned copper sleeves are produced for wires with a cross-section from 2.5 to 300 mm2. Accordingly, with an increase in the cross-section of the conductor, the sleeve itself has larger dimensions (diameter and length). For combined products, two numbers are written through the fraction, one indicates the cross-section of the copper conductor, the second - the aluminum.

By design

The sleeves also differ in design. They can be hollow, that is, inside they are bare through tubes. And they come with a partition in the middle, which allows you to adjust the depth of the conductors, that is, the tips of both connected wires will enter the sleeve to the same length. Combined sleeves are produced with partitions, which are used when connecting conductors at the joint.

How to connect electrical wires by soldering

Connecting electrical wires by soldering is very reliable. You can solder untwisted wires, but such soldering will be fragile due to the fact that the solder is a very soft metal. In addition, it is very difficult to lay two conductors parallel to each other, especially when suspended. And if you solder on some kind of base, the rosin will stick the soldering area to it.

A layer of rosin is applied to the pre-tinned and twisted conductors with a soldering iron. If another flux is used, it is applied in the appropriate manner. The power of the soldering iron is selected based on the cross-section of the wire - from 15 W when soldering headphones to 100 W when soldering twisted wires with a cross-section of 2.5 mm². After applying the flux, tin is applied to the twist with a soldering iron and heated until the solder completely melts and flows into the twist.

After the soldering has cooled, it is insulated with electrical tape or a piece of heat-shrinkable tubing is put on it and heated with a hairdryer, lighter or soldering iron.

When using a lighter or soldering iron, be careful not to overheat the heat shrink.

This method reliably connects wires, but is only suitable for thin wires, no more than 0.5 mm², or flexible ones up to 2.5 mm².

Scope of use of crimpers for terminating electrical wires

The area of ​​application of the tool is influenced by its design and shape. The variety of models produced by manufacturers allows specialized companies to perform any task.

Pliers for terminating stranded wires and thin-walled lugs

This tool is used for crimping electrical cables of small thickness. Their cross-sectional area can even be 0.25 mm². Such wires are connected to pin-type ferrules.

On a note! IEK makes one of the highest quality multi-strand wire termination tools available.

Thanks to the crimping of electrical wires using high-quality bushings, numerous wires do not spread out at the end of the cable. This allows you to conveniently and quickly connect it to the terminals of various devices.

Pliers for fine tips and stranded electrical wires Source bts-instrument.com

Press pliers for wires with multiple cores and thick-walled ferrules

This tool is larger in size compared to the pliers described above. Each model is made with a matrix for tips of specific sizes. For example, the KVT company produces the PK-16 crimper, which has 5 working zones. After using the pliers, a special mark is imprinted on the sleeve.

The name of the press jaws may contain the letter “U”. It means that the crimper design has a ratcheting mechanism, which is located in the handle of the tool.

Terminal block connection

A development of the bolted connection is the terminal connection. Terminal blocks come in two types - with a rectangular pressure washer and with a round one. When using a terminal block with a pressure washer, the insulation is removed to a length equal to half the width of the terminal block. The bolt is released, the wire is slipped under the washer and the bolt is clamped again. On one side, you can connect only two wires, preferably of the same cross-section and only flexible or only single-core.

Connecting to a terminal block with a round washer is no different from using a bolted connection.

The connection of the wires is reliable, but cumbersome. When connecting wires with a cross-section of more than 16 mm², the connection is unreliable or the use of lugs is necessary.

Internet cable crimping methods

The cord is crimped in order to fit into the connector of the network card or socket and be fixed there with all contacts. All 8 contacts of a 4-core twisted pair cable and the outer covering are made in the form of a dense cord, which initially does not contain any connectors. This is done so that the wire does not cling to other things during storage and transportation. This also allows it to fit into small holes in the walls when installed in an apartment. If crimping was carried out at the cable manufacturer's plant, pulling would take longer and require more resources.

Direct crimping methods

Direct connection

The direct connection wire is often called a patch cable and is required to replace the wireless connection. Its main feature is that the wire contacts on one side are completely consistent with the contacts on the other. In this case, one standard is used: either T568A or T568B.

It is used to connect:

• Switch and router;
• Computer and switch;
• Computer and hub.

Schematic example of a cross connection

Cross connection

The crossover type is used to connect two computers directly. Its main difference from a straight cable is that it uses different standards for the arrangement of contact groups. The T568A standard may be used at one end, and T568B at the other. It is most often used to combine devices of the same type, namely:

• Switch and Switch;
• Switch and hub;
• Two routers;
• Two computers;
• Computer and router.

You may be interested in this IKK Features

Crimping the wire with long-nose pliers

How to connect wires by crimping

Another way to connect wires is crimping. This is a method in which a copper or aluminum sleeve is placed on the wires or cables to be connected, and then crimped with a special crimper. For thin sleeves, a manual crimper is used, and for thick ones, a hydraulic one is used. This method can even connect copper and aluminum wires, which is unacceptable with a bolted connection.

To connect using this method, the cable is stripped to a length greater than the length of the sleeve, so that after putting on the sleeve, the wire sticks out 10–15 mm. If thin conductors are connected by crimping, then twisting can be done first. If the cable has a large cross-section, then, on the contrary, in the stripped areas it is necessary to align the wire, fold all the cables together and give them a round shape. Depending on local conditions, the cables can be folded with the ends in one direction or in the opposite direction. This does not affect the reliability of the connection.

A sleeve is tightly placed on the prepared cables or, when laid in opposite directions, the wires are inserted into the sleeve from both sides. If there is still free space in the sleeve, it is filled with pieces of copper or aluminum wire. And if the cables do not fit in the sleeve, then a few wires (5–7%) can be cut off with side cutters. If you do not have a sleeve of the required size, you can take a cable lug by sawing off a flat part from it.

The sleeve is pressed 2–3 times along its length. The crimping points should not be located at the edges of the sleeve. It is necessary to retreat 7–10 mm from them so as not to crush the wire during crimping.

The advantage of this method is that it allows you to connect wires of different sections and from different materials, which is difficult with other connection methods.

Tools and materials

To work, you will need manual (or mechanical) press pliers. They crimp a sleeve with conductors with a cross section of up to 120 mm2. For conductors with a larger cross-section, a press is required, which is driven by a hydraulic drive.

There are pliers with dies for different sections and with adjustment of the punches. A very convenient tool in the sense that you don’t have to constantly reset it to other sizes, just turn the punch screw or matrix to the desired section.

When working with aluminum wires, you will need a special quartz-vaseline paste, which removes the oxide film on the wires and prevents its reappearance.

Copper conductors do not need such treatment, but it is still advisable to lubricate them with ordinary technical petroleum jelly to reduce friction. During deformation, the cores can be damaged, and lubricant minimizes this risk.

Application area

Press pliers have a wide range of applications in the field of radio, - and electrical engineering. Use a crimper for crimping:

• thin-walled tips of stranded wires;
• thick-walled stranded wire connectors;
• large cross-section cable sleeves;
• sleeves for serial connection of wires;
• RJ-45 connectors for computer cables.

Crimping of thin-walled stranded wire lugs

Press tongs KVT

Thin-walled connectors are divided into three types:

1. NSHVI;
2. Sheath;
3. Ring.

NSHVI

Pin lugs are necessary for reliable fixation of wires in sockets of radio equipment. The lugs are made of thin metal to tightly grip small cross-section multi-core cables ranging from 0.5 to 3.5 mm2. The fittings are designated by the marking NSHVI.

Important! Crimpers with markings for opening sizes of 0.5-3.5 mm2 reliably and firmly crimp NShVI tips, which are often used in assembling various radio devices. NSHVI

NSHVI

Sheath

Thin-walled terminals for stranded wires include sheath connectors. They are used for serial connection of wires in devices with high temperature conditions where soldering may lose its properties. These are irons, electric kettles, microwave ovens and various heating devices.

To crimp sheath-type terminals, crimpers with special dies are used. The terminal has two pairs of brackets. One of them clamps the bare bundle of wires, the second brackets cover a section of the insulated conductor. The terminals are distinguished into “father” and “mother”. The connection occurs by inserting the plate of one tip into the tubular clamps of the second terminal.

Scabbard terminals

Ring

The terminal has a ring configuration for screw fastening. For crimping them, crimpers with dies for wire cross-sections from 0.25 to 16.8 mm2 are used. Ring shanks are used for fastening wires in various power distribution boxes and panels.

Ring thin-walled tips

Crimping thick-walled stranded wire connectors

Massive lugs are used for crimping multi-core wires and cables with a maximum cross-section of 16 mm2. Crimping pliers type PK-16U are designed for such work. The crimper develops a powerful force on the die jaws. Therefore, press pliers are used only for multi-core wires. The tool can easily bite through a single core.

Pliers PK-16U

Note! The letter “U” in the marking of a crimping tool means that the tool is equipped with a reinforced ratchet mechanism

Crimping of large cross-section cable sleeves

For crimping large-section cable sleeves, a manual hydraulic press is used. These are press pliers that develop powerful force thanks to the built-in hydraulic mechanism.

Hydraulic Press

A reinforced crimper is especially needed when laying and switching power cables in power switchboards, both at industrial facilities and in buildings for various purposes.

Consistent crimping of wire sleeves

The serial connection of wires is made by increasing the length of the electrical circuit. This is especially in demand when connecting cores of different metals. When connecting an aluminum core and a copper wire, a through crimp sleeve is used. The sleeve ensures non-close contact of unlike metals, which eliminates the destructive interaction of atomic lattices of different conductors.

Crimping is carried out in the following order:

• the wires are freed from insulation at a distance equal to half the length of the sleeve;
• the cores are inserted into the sleeve on both sides;
• Crimping is done with a crimper on both sides of the sleeve.

Crimping RJ-45 connectors of computer cables

Polymer RJ-45 connectors provide quick connection of cables to computers or connection of additional equipment to them. The cable in this case is a twisted pair, where the insulated cores are intertwined with each other.

Network cable crimping pliers

For twisted pair cables, crimpers with special matrices are used. Crimping is carried out in several stages:

• the wire is cleared from the outer sheath to a length equal to the depth of the plastic connector;
• twisted pair is divided into individual wires and grouped by color in a certain position (see below for additional information);
• the wiring is inserted into a special opening of the pliers and the ends of the wires are stripped of insulation;
• the plastic connector is covered with a crimper;
• a group of cores is inserted into the RJ-45 housing until it stops;
• squeezing the plastic with pliers and pressing the wires into the connector.

Polymer RJ-45 lug

The wires of the network cable are grouped from left to right before entering the connector:

• white-orange;
• orange;
• green-white;
• blue;
• blue-white;
• green;
• white-brown;
• brown.