Connecting the cables together. Methods for reliable connection of wires. Welding – high reliability in any conditions

How to connect the wires correctly? Every man has asked this question at least once in his life, even if he is not an electrician. In everyday life, we often have to face similar questions. The electrical cable plug has fallen off, the chandelier wire has broken, the socket has stopped working, the connection to the home telephone has been lost, there is no voltage in the car’s on-board network, etc. All these problems can be easily solved if you have basic knowledge of electrical engineering and observe safety when carrying out installation or repair work.

In this article we will look at how to properly connect wires when installing electrical wiring, breaking an electrical circuit, or simply for the purpose of repairing electrical equipment.

Why you can’t directly connect wires of different metals

Let's start with the fact that you can't just take and connect conductors without taking into account the properties of the material from which they are made. Each of the metals used to transmit electricity, most often aluminum, copper and steel, has a different density, resistance and conductivity. In addition, it is necessary to take into account such a factor as the electrochemical potential that arises when current is applied to the metal.

Serious problems, for example, can be caused by improper connection of copper and aluminum wires. This question is often faced by specialists who repair wiring in our homes. The fact is that most old houses and apartments have copper wiring. After all, about 30 years ago copper was cheap, and in terms of electrical performance it is significantly superior to aluminum.

Today, copper wires are used quite rarely. Aluminum ones took their place.

But what happens if you combine copper with aluminum? The latter, being a metal with high oxidation rates, forms a specific film on its surface that has a fairly high electrical resistance. This is especially true when exposed to moisture.

Copper also has a similar film, but its resistance is much lower. Because of this difference, the direct connection of copper and aluminum wires causes difficult current conduction, and mutual oxidation processes lead to the formation of shells on the conductors, heating, sparking and even fire.

But what to do when you need to connect wires from different metals? There are special devices for this. We will now talk about them in the context of a review of existing types of connections.

1. Twisting (twisting).
2. Bandaging.
3. Welding.
4. Soldering.
5. Crimping.
6. Riveting.
7. Terminal connection.
8. Connection using terminal strips and clamps (terminal blocks).
9. Threaded connection.
10. Connection by piercing conductors.
11. Cable compression.
12. Connection using a “nut”.

Twisting

Twisting is the simplest connection of wires. It is enough to strip them of insulation, twist them tightly together using pliers - and you can test them. Yes, such an installation has a right to exist, but not for a long time, especially if we are dealing with different conductor materials. It can only be used as a temporary connection and, at the slightest opportunity, should be replaced with a more reliable one. By the way, this installation is not mentioned at all in the Electrical Installation Rules (EPI), as it is considered unreliable and quite dangerous.

Such a connection of wires is categorically not recommended for installation or repair of electrical networks, electrical wiring in rooms and cars.

But there is also a reliable twist, or rather, an improved one. ZIS caps are available for sale, specially designed to increase the reliability of twisting. They are made of fireproof plastic and have a cone-shaped spring inside. Having placed a regular twist inside such a cap, you need to turn it until it stops. The coils of the spring will open under the influence of your force, and then securely fix the ends of the conductors together. In this case, the cap will play the role of a kind of electrical insulator. This method is often used to provide wire connections in a residential or industrial distribution box.

Bandaging

Banding is also a type of twisting. It is not reliable and cannot be recommended for installation or repair of electrical wiring.

The essence of banding is that the bare ends of two, three or more conductors are folded together and wrapped with softer wire with good conductivity, for example copper with zinc coating, after which the contact point is carefully insulated.

Welding

Next, we will look at more reliable types of wire connections. One of such installations is welding of electrical conductors. It can be called an improved and legalized twisting, because the ends of the wires must be welded after they have been twisted. This process can be carried out in two ways: using electric arc welding and thermite welding. In the first case, metal electrodes are used, and in the second, a special flammable mixture is used.

If everything is clear with arc welding, then we will consider in more detail how installation occurs using thermite powder.

There are special thermite cartridges of various diameters, inside of which there is a compressed combustible mixture. It consists of crushed aluminum, magnesium, calcium, silicon, titanium and other metals. This powder burns, releasing enormous amounts of heat. Under its influence, the conductors, being placed in such a cartridge, are firmly welded to each other. To get a similar connection of wires, you just need to strip them of insulation, twist them, place the twist inside the cartridge and set it on fire with a special match included in the kit. After welding, it is necessary to remove the slag deposits formed as a result of combustion.

Naturally, only large diameter wires and cables can be connected by welding. This method is not intended for domestic needs.

Soldering

Another fairly common, but not particularly reliable installation method is soldering. It is best suited for domestic use, unless we are talking about electrical wiring. According to GOST R 50571.5.52-2011 and PUE, this connection method is not recommended for high voltage electrical circuits, since the solder has a fairly low melting point. But it is quite suitable for repairing household electrical appliances.

It should be noted right away that this method can only be used to connect copper wires, since it is unlikely that aluminum can be soldered at home.

In order to carry out high-quality soldering, you will need:

• soldering iron with a power of 60-100 W;
• solder (tin-lead);
• flux (rosin);
• small brush (for applying flux);
• sandpaper.

We strip the wires by 3-4 cm, sand them and twist them together. Now, using a brush, apply flux to the connection and solder the wires to each other, applying molten solder.

If our wires are multi-core, we first twist each of them and cover them with solder.

Sometimes it becomes necessary to connect not two, but three, four or more conductors. Of course, you can’t do this without special devices, but for circuits using low voltage, you can use an installation called a “star.” This is a kind of soldered twist of several conductors. Connecting wires with a star involves winding the taps in a spiral around the main core, followed by covering the contact areas with solder and insulation.

Crimping

Crimping is one of the most reliable types of connections and meets all the requirements of electrical installation rules. Its essence lies in the fact that the wires are placed in a special metal sleeve and crimped with a special tool.

To do this, it is enough to have:

• a sleeve of the appropriate size made of copper or aluminum (the material must match the material of the conductors);
• knife for removing insulation;
• special press pliers (pliers will not work);
• insulating tape.

We strip the wires to the length of the sleeve, twist them and place them in the sleeve. Next, using pliers, we press our connection and isolate it for safety reasons.

There are also special tube sleeves for longitudinal connection, i.e., extending the conductor. In this case, the wires are inserted on both sides of the tube, after which each of them is crimped separately.

This connection of electrical wires is widely used when installing electrical wiring in residential and industrial premises.

Riveting

This method cannot boast of its popularity, but its reliability is beyond doubt. Here, a special rivet is used as a connecting element, which, in fact, is needed in order to reliably connect the conductors by riveting. The rivet material - copper or aluminum - is selected to match the material of the wires.

This wiring diagram is often used in the installation and repair of 380/220 V consumer electrical networks.

To connect conductors using the riveting method, you will need:

• rivet (copper or aluminum);
• two steel washers (flat and spring);
• special tool - riveter.

First, the end of one wire, stripped and twisted into a ring, is first put on the rivet, then a spring washer, then a similarly processed and formed end of the other wire and a flat washer.

Terminal connection

Terminal connections are most common in automotive on-board electrical circuits, where it is often necessary not only to connect wires, but to connect them to some device, be it a relay, sensor, backlight, etc., which have special standardized contacts for this. Its essence lies in the fact that a terminal of the required size is put on the end of the wire, stripped of insulation, after which its lower part is crimped with ordinary pliers. For more reliable contact, the connection point can be soldered.

Terminal strips and clamps

Installation using “terminal blocks” is probably the most common method for connecting wires of household electrical wiring. There is no need for welding, soldering or special tools. It is enough to have special “terminal blocks” for connecting wires, sold in any hardware store for pennies, and an ordinary screwdriver. This type of installation is very reliable and durable.

“Terminal blocks” for connecting wires are of two types:

• with bolt clamp;
• self-clamping with spring clamp.

The first option involves the use of a plastic terminal strip with contacts clamped using bolts. To carry out such an installation, you need to unscrew the screw with a screwdriver, insert the wire into the hole specially provided for it and clamp it in the same way.

Self-clamping terminal blocks are even easier to use. Their design is equipped with a flat-spring mechanism, driven by special levers on the body. It is enough to cock this lever, insert the end of the stripped wire under it and release. The spring itself will clamp the wires and securely fix them.

These methods of connecting wires have practically no disadvantages, with the exception of one thing - the quality of the materials from which they are made. You probably remember the old Soviet terminal strips, made of hard, non-flammable black plastic. They are still often found in old electrical wiring today and are ready to serve for decades. Modern “terminal blocks” cannot boast of this, so when purchasing, pay special attention to the housing material and do not purchase cheap models.

Threaded connection

Threaded wire connections are most often used in various input and distribution devices of electrical installations. This installation is quite reliable and also does not require any special skills. An ordinary steel bolt is used as a connecting element. The ends of the wires, after stripping, are formed into loops and put on the bolt leg mixed with steel washers so that there is a washer between them, as well as on both sides of the conductors. After this, the structure is clamped with a nut.

This installation is advantageous in that it allows the connection of aluminum wires used in consumer power lines and copper wires, as well as their combinations.

Piercing

There is another type of installation, used exclusively for power lines, various electrical installations and their distribution devices. This is piercing. It is carried out using a special piercing clamp, which is placed on the conductors and, squeezing them, cuts off the insulation, forming contact between the cores.

Its advantage over other methods is the possibility of installation without turning off the line power, because the master does not have direct contact with the conductor itself.

Cable compression

Cable compression allows you not only to connect two conductors from different metals, but also to create a lateral branch from them. It consists of two steel plates, flat or with special bulges for the diameter of the cable, connected with several bolts. Having loosened these bolts, the bare conductor strands are inserted between the plates in a certain order. Once installation is complete, the bolts are tightened, holding the wires securely. With the help of such plates it is possible to compress ordinary twisting, significantly increasing its reliability.

Connection "nutty"

"Oreshek" is an improved version of the cable clamp. Its design also involves the use of two shaped plates pressed against each other with bolts. However, the “nut”, among other things, has a collapsible body in the form of a plastic ball, which is put on the connection after installation is completed. This feature allows this connection to be used outdoors.

1. When connecting wires intended for transmitting high voltage yourself, follow at least the first two of the three rules of an electrician: “Disconnect, check, ground.”
2. When choosing a connection type, choose the most reliable and secure one.
3. Never use installations such as twisting or banding to connect wires outdoors.
4. Each connection must be reliably insulated.
5. Having no idea about electrical engineering, do not try to repair an electrical network or electrical appliance yourself; it is better to trust the specialists.

It often happens that wires of different sections come into the junction box and they need to be connected. It seems like everything should be simple here, as with connecting wires of the same section, but there are some peculiarities here. There are several ways to connect cables of different thicknesses.

Remember that you cannot connect two wires of different sections to one contact in a socket, since the thin one will not be pressed tightly by the bolt. This will lead to poor contact, high contact resistance, overheating and melting of the cable insulation.

How to connect wires of different sections?

1. By twisting with soldering or welding

This is the most common way. You can twist wires of adjacent sections, for example 4 mm 2 and 2.5 mm 2. Now, if the diameters of the wires are very different, then good twisting will no longer work. When twisting, you need to make sure that both wires wrap around each other. Do not allow a thin wire to wrap around a thick one. This may result in poor electrical contact. Do not forget about further soldering or welding. Only after this will your connection work for many years without complaints.

2. Using screw clamps ZVI

I already wrote about them in detail in the article: Methods of connecting wires. Such terminal blocks allow you to insert a wire of one cross-section on one side, and a different cross-section on the other side. Here each core is clamped with a separate screw. Below is a table that will help you choose the right screw clamp for your wires.

Screw clamp type		Permissible continuous current, A
ZVI-3	1 - 2,5	3
ZVI-5	1,5 - 4	5
ZVI-10	2,5 - 6	10
ZVI-15	4 - 10	15
ZVI-20	4 - 10	20
ZVI-30	6 - 16	30
ZVI-60	6 - 16	60
ZVI-80	10 - 25	80
ZVI-100	10 - 25	100
ZVI-150	16 - 35	150

As you can see, using ZVI you can connect wires of adjacent sections. Also remember to look at their amperage rating. The last digit in the screw terminal type indicates the amount of permissible continuous current that can flow through this terminal.

We strip the conductors to the middle of the terminal...

We insert them and tighten the screws...

3. Using Wago universal self-clamping terminals.

Wago terminal blocks have the ability to connect wires of different sections. They have special sockets where each wire “sticks” into. For example, you can connect a 1.5 mm 2 wire into one hole of the clamp, and 4 mm 2 into the other, and everything will work properly.

According to the manufacturer's markings, terminals of different series can be used to connect wires of different sections. See table below:

Wago terminal series	Cross-section of connected conductors, mm 2	Permissible continuous current, A
243	0.6 to 0.8	6
222	0,8 - 4,0	32
773-3	0.75 to 2.5 mm 2	24
273	1.5 to 4.0	24
773-173	2.5 to 6.0 mm 2	32

Below is an example with series 222...

4. Using a bolted connection.

A bolted connection of wires is a composite connection consisting of 2 or more wires, a bolt, a nut and several washers. It is considered reliable and durable.

Here it goes like this:

1. we strip the core by 2-3 centimeters, so that it is enough for one full revolution around the bolt;
2. we make a ring from the core according to the diameter of the bolt;
3. take the bolt and put it on the washer;
4. We put a ring of conductor of the same section on the bolt;
5. then put on the intermediate washer;
6. put on a ring made of a conductor of a different cross-section;
7. We put the last washer and tighten the whole thing with a nut.

In this way, you can simultaneously connect several wires of different sections. Their number is limited by the length of the bolt.

5. By squeezing the branch “nut”.

I wrote about this connection in detail with photographs and corresponding comments in the article: Connecting wires using nut-type clamps. Let me not repeat myself here.

6. Using tinned copper tips through a bolt with a nut.

This method is well suited for connecting large cross-section cables. For this connection, it is necessary to have not only TML tips, but also crimping pliers or a hydraulic press. This connection will be a little bulky (long), and may not fit into some small junction box, but it still has the right to life.

It's easy to connect here. A ferrule is placed on each core, they are crimped and connected using a bolt with a nut and washers. This area is then insulated using insulating tape or heat-shrinkable tubing (it must be placed over the wire before connection).

Unfortunately, I didn’t have a thick wire and the necessary tips on hand, so I made a photo from what I had. I think you can still understand the essence of the connection from it.

I think I've listed everything. If you know other ways to connect wires of different sections, then write in the comments.

Let's smile:

There are two people sitting in the cell:
- Why are you imprisoned?
- For murder.
- How much did they give?
- 7 years. What are you for?
- For poaching.
- How many?
- Fifteen.
- Who were you hunting for?!
- I’m walking, so I’m hunting, I see a telegraph pole, an eagle is sitting on the pole. Well, I'm a doublet...
- So what?! 15 years for an eagle? Did you even kill him?
- Yeah... shot, claws in one direction, pliers in the other.

Today, there are many ways to connect wires in a junction box.

Here are the factors that determine the choice of connector:

1. Core material (copper or aluminum).
2. Working conditions (outdoors, in an apartment, in water, in the ground, in the floor, normal conditions).
3. Number of conductors (two, three, four, etc.).
4. Core cross-section (same, different).
5. Core structure (single-wire or multi-wire).

Based on these factors, the most suitable and correct method is selected. First, let's look at the materials that can be used to connect electrical wires in a junction box.

Existing methods

The following connection options are considered the most popular and effective:

• use of terminal blocks;
• installation of spring terminals (wago);
• fixation with PPE (plastic caps);
• crimping with sleeves;
• soldering;
• twist;
• installation of “nuts”;
• use of bolts.

Let's consider the essence, advantages and disadvantages of each method!

Installation of PPE caps

PPE stands for connecting insulating clips. The products are ordinary plastic caps that have a special spring inside that holds the wires.

Most often, such caps are used to connect cores in junction boxes.

Advantages of using these products:

• low cost of PPE;
• the caps are made of non-flammable material, so there will be no twisting at the site;
• quick installation;
• The caps have a wide range of color shades. For example, if the wires do not have a wire, you can use PPE to mark it (using a white, blue and green cap).

Flaws:

• relatively poor quality of insulation and fixation;
• It is impossible to combine aluminum with copper.

Crimping with special sleeves

Stranding and insulation

The old “grandfather’s” method consists of twisting the cores together. The essence of the work is that the conductors are stripped and carefully twisted with pliers, after which the twisted area is insulated.

Advantages:

• simplicity of electrical installation work;
• no material costs.

Flaws:

• poor quality of core fastening;
• The connection of aluminum and copper products is unacceptable.

We’ve sorted out the existing methods of connecting wires in a box, now let’s look at the other important issues on this topic.

What to do if there are several wires?

There are usually no problems when connecting two contacts. But what to do if you need to combine three, four or more at the same time?

• using wago terminal blocks;
• crimping with sleeves;
• soldering;
• twisting using sizes;
• twisting and wrapping with electrical tape.

We discussed in detail the order of connecting the wires for each method above. We strongly recommend that you use the first option, because... it is one of the most modern and effective. At the same time, the cost of the vag is not too high, and the wiring lasts more than 30 years.

What to do if the wires are of different sections?

To connect cores of different cross-sections in the junction box, it is recommended to use the same Vago terminal blocks, or a cheaper option - ordinary terminal blocks. In this case, you need to carefully tighten the wires with a screw or secure them with a flag, and that’s it, the work is finished.

We draw your attention to the fact that if the wires are made of different materials, then it is necessary to use special blocks with paste inside, which will prevent oxidation of the wires. Such pads include products from Wago.

Also, cores of different sections can be secured by soldering.

Combining stranded and single-core wires

Connecting single-core and stranded wires separately has no special features, so you can use any of the methods listed above.

In order to carry out fastening, you must choose one of two options: vago terminals or soldering. It all depends on your preference; we have provided the advantages and disadvantages of each method.

How to carry out work in water and land

During electrical installation work, a situation often occurs when it is necessary to fasten electrical wiring under water or in the ground. Now we will briefly look at the features of each case!

In water (for example, when installing a submersible pump), it is recommended to use the following technology. To begin with, the ends are soldered, after which the soldering area is carefully insulated with hot-melt adhesive, over which it is placed. If everything is done efficiently and conscientiously, the joint will be airtight and safe. Otherwise, the electrical network may fail.

To connect an electrical wire in the ground (for example, after it has been mechanically damaged), it is recommended to use the method provided above (hot glue and heat shrink), but it is better to protect yourself and use the following technique. Clamp the ends of the cable using a terminal block, install a sealed junction box, and then carefully fill the box with a special silicone sealant. Please note that the underground route must additionally be placed in a pipe or box to ensure reliable operation!

In stranded wires, the cross-section is formed by several, sometimes intertwined, cores. Knowing how to connect stranded wires to each other, you can easily do this work yourself and get a strong contact that is absolutely safe during operation.

Where are stranded wires used?

Any stranded conductor contains at its base a large number of thin wires. The use of a multi-core cable is important in areas that require a large number of bends or, if necessary, to pull the conductor through holes that are too narrow and long enough.

The scope of application of stranded conductors is presented:

• extended tees;
• mobile lighting devices;
• automotive wiring;
• connecting lighting fixtures to the electrical network;
• connecting switches or other types of levers to influence the electrical network.

Flexible stranded conductors can be twisted repeatedly and easily, which does not negatively affect the functionality of the system. Among other things, this particular type of electrical wiring is distinguished by plasticity, and greater flexibility and elasticity is imparted to the wire by weaving a special thread, which in strength and composition is a bit like nylon.

Methods for connecting stranded wires to each other

The methods used today for electrical connections of stranded conductors are distinguished by the ability to obtain not only strong, reliable and durable, but also completely safe contact of the conductors.

Stranding of stranded conductors

This option is the easiest to implement and intuitive, not requiring the use of special equipment or professional tools.

Twisting is the easiest way to connect stranded wires

The second method consists of the following steps:

Twisting wires using the third method:

There is also a fourth method, which is as follows:

Soldering method

Soldering the conductors using a household soldering iron ensures high-strength contact and good electrical conductivity. Tinning of stranded conductors is carried out using rosin (flux) and standard solder using standard technology.

Terminal type connections

The use of terminals of different types is the most affordable way to connect multi-core wires in everyday life. In most cases, the terminal blocks used are divided into a couple of main types.

The principle of operation of clamping terminals involves fixing the wire using a built-in spring mechanism.

Terminals are often used to connect wires

The screw-type terminal block involves reliable fixation of all connected stranded wires using a screw. To increase the area of ​​wire contact with a conductive surface, an additional bend of the core is required.

The wires in the terminal block are secured by tightening the screws

Stage-by-stage execution of work:

Crimping method

The crimping method involves connecting wires or cables using a copper or aluminum sleeve using special crimping pliers of a hydraulic or manual type.

In this case, the connection is made using a special sleeve

The pressing technology involves stripping the insulation according to the length of the sleeve, and conductors that are too thin should be connected by twisting. Then all the cables are folded together and placed inside the sleeve, after which double crimping is performed along the entire length. The method allows you to perform a reliable and safe connection of multi-core wires made of different types of materials.

Bolted connection

The simplest, but not reliable enough way to connect stranded wires is twisting followed by bolting. This detachable connection option is most often used in open wiring conditions.

Bolted connection is the simplest, but not very reliable

To increase the level of reliability of the connection of stranded wires, it is recommended to strip the ends of insulation, then tin the cleaned areas and fasten them with a bolt.

Application of connecting insulating clamps

PPE elements are used when it is necessary to connect stranded wires with a small cross-section (within 25 mm2). The design feature of this clamp is a plastic body with a built-in cone-shaped spring.

This method is suitable for connecting wires with a small cross-section

Stranded wires are first connected into one bundle using twisting, onto which the clamping part is then screwed. Among other things, the wire connection does not require additional insulation.

Welding method

A permanent connection is the most reliable method when working with multi-core wires. When welding is performed correctly, the general indicators of mechanical strength and contact resistance in terms of reliability do not differ from similar parameters of a solid conductor.

Welding connection of wires is considered the most reliable

Welding can be performed on alternating and direct current. At the preparatory stage, the wires are stripped of insulation, after which they are twisted and straightened by trimming the ends. To ensure that the conductors do not overheat during the welding process, it is necessary to ensure high-quality heat removal.

Security measures

In order to ensure safe operation of connected stranded wires, it is important to insulate all parts of the electrical wiring. Proper insulation helps prevent dangerous contact of conductive parts with each other or with the human body. When choosing an insulating material, it is necessary to take into account the operating conditions of the electrical circuit, but in most cases, insulating tape, as well as a special vinyl or heat-shrinkable tube, are used for this purpose.

If the connection area is exposed to the negative effects of high temperatures, it is recommended to use varnished cloth or fabric insulating tape as an insulating material. Correct execution of all stages of electrical installation is of no small importance. Only with reliable connection and proper connection of all elements of the electrical network is it possible to minimize the risk of areas with poor contact, and also prevent local overheating and electrical wiring breaks.

Multicore cables are a popular and widespread option, widely used for arranging electrical wiring for various purposes. The general rules for the separate connection of stranded and single-core conductors do not have any differences or features, therefore it is allowed to use twisting, screw clamps, PPE elements, welding and soldering for this purpose.

When doing DIY repairs of household appliances or electrical wiring maintenance, any craftsman is faced with the issue of safely creating electrical circuits by connecting wires to each other or connecting them to output terminal blocks.

At the same time, even experienced electricians can make mistakes in ensuring the reliable formation of electrical contacts, which will not appear at the initial moment of operation, but will create a malfunction over time.

The metal of the wire is made for the ideal flow of electric current through it. For this purpose, it is cast from a homogeneous composition of copper or aluminum alloy with a standard cross-section along its entire length.

To create contact, simply touching the surfaces without any effort is enough. The photo below shows that if you place the exposed core of a second wire on one bare section, an electrical connection is formed between them. Through it, a 4-volt battery can make a light bulb from a flashlight glow.

Home wiring is much larger - 220 volts. An erroneous conclusion is drawn from this fact: it is easy to create contact between electrical wires.

Novice electricians simply forget the issue of providing reliable contact resistance for long-term operation of such a connection.

When installing wires, the home master is faced with the need to process:

1. conductor;
2. insulation layer.

These are two interrelated processes that ensure the final result - the optimal flow of electric current through the created circuit.

How to work with wire insulation layer

The dielectric coating protects the metal core from unexpected circuits. When it is violated, leakage currents immediately appear, leading to malfunctions.

The wire insulation layer may be damaged:

• under mechanical influence;
• overheating;
• from solar radiation.

Protection is required from all these destructive factors. Moreover, if necessary, removing the insulation layer to connect the wire, you must not damage the surface of the metal core.

To do this job safely, many tools with cutting edges have been created. Let's consider their use at home.

Electrician's knife

Trade provides a wide range of their designs. Some workers prefer to use knives made by themselves from materials selected according to individual characteristics.

When choosing the right model for your needs, pay attention to them, eliminating the possibility of accidental cuts.

The main condition for proper operation is the orientation of the blade relative to the axis of the wire. The angle formed should be acute. Then the knife will cut off the dielectric layer and at the same time slide along the metal without touching it.

Installing a knife perpendicular to the wire will cut not only the insulation, but also the surface of the metal core. This means it will reduce its cross-section, break the connection, increase the electrical resistance to the passing current, which will cause excessive heating and aging of the dielectric layer.

Deep penetration of a sharp blade into the metal leads to rapid breakage when the wire bends. Such scratches can be identified by careful visual inspection. But who does this?

A lineman's knife is a common tool for every electrician, but not all home craftsmen have good practical skills in removing insulation with it. And experienced specialists can accidentally cut metal and not notice the mistake.

Therefore, industry has long been producing tools adapted for these purposes.

Stripping pliers

Their industrial designs have been produced for quite some time, and the design is constantly being improved. Let's look at them with examples.

Rare sample

Combined pliers were produced for the Soviet electrician's tool kit, allowing:

• Safely cut through and remove insulation from wires with typical cross-sections of 1.5 and 2.5 mm square;
• bite copper wires;
• bend neat rings;
• perform other operations.

They cope with their tasks normally even now, despite their unsightly appearance, slight wear and heavy weight. To strip the insulation from the ends of the wire, it is enough:

• insert it into the corresponding slot;
• squeeze the handles to cut the insulation;
• ensure axial movement of the pliers to the end of the wire.

The surface of the metal core is not damaged and remains in its original condition.

The increased compression force of the handles is compensated by the design of the pliers and does not create malfunctions.

Modern models

They have significantly greater technical capabilities, allowing them to work with wires of small and large cross-sections, both monolithic and stranded conductors.

The case, made of high-strength plastic, has dielectric properties and is lighter in weight. Various regulators and devices are installed on it.

Before work, such a tool must not only be studied, but also correctly adjusted for each cross-section. Otherwise he will create problems.

Pliers and side cutters

Among electricians, there is a category of workers who remove insulation in a similar way. The error of this method is the uncontrolled squeezing force of the handles, leading to squeezing of the metal wire, deformation and destruction of its surface.

This error may occur periodically in a random pattern. It depends on the employee’s experience, condition, attentiveness and other factors.

Removing insulation in this way is dangerous, and the places where it is removed must be carefully checked. Particular attention should be paid to stranded strands.

How to work with metal core wires

Methods for creating electrical contacts through wire are based on the use of:

• screw terminals;
• twists;
• soldering or welding;
• spring compression.

Screw connections

The connection can be made:

• pressing the ring;
• by pressing the core with a screw directly or through washers.

Making rings

When screwing in the screw, the ring of wires should work to compress, not unwind. They must be separated with wide washers on each side of the surface. A wire that is incorrectly clamped into a ring may come out of the fastening during operation.

This method is considered the most reliable and is widely used in energy enterprises.

Using terminal blocks

The metal core is inserted into a special socket and held in it by the tightening force of a screw through the surface of a spring steel washer or its threaded end.

With this method, it is important to maintain the nominal value of screw screwing force. Weak twisting leads to the wire being pulled out of the terminal (you need to check it with your hand), and excessive twisting crushes the wire.

Twisting wires

The created contact surface between the cores must cover the cross-sectional area with a margin.

To do this, the twisted ends with the insulation removed are made of a large length, about 10 cm, and they are twisted using pliers quite tightly with an even distribution of turns.

When twisting, the wires should be well crimped and stretched to ensure reliable contact of the surfaces.

Ways to Create an Improved Twist

The contact resistance of the surface layer can be reduced by:

• welding the final section of the connection;
• soldering twisted surface.

Not every home master can use this technology. It requires special equipment - a welding transformer for copper or aluminum, or. Therefore, in home wiring, the twists are immediately covered with electrical tape or insulated with heat-shrinkable tubes.

Typical twist errors

Often, electricians make short ends of the wire, which, under heavy loads, cause increased heating of the contact connection being created.

Insulating caps for connecting wires

The contact is created by compressing the surfaces of each wire with the force of a spiral spring built inside the housing.

Metal wires of the appropriate diameter, stripped of insulation, are screwed into a spiral, creating a twist. The steel spring straightens a little when the ends of the wire are inserted and compresses them into the socket.

Errors in installing wires with PPE caps

Poor connection contact quality occurs from:

• incompetent work of electricians;
• the use of low-quality counterfeits of branded products;
• incorrect calculation or installation of electrical wiring;
• incorrect and protective shutdown devices.

To prevent possible malfunctions, individual craftsmen increase the surface of the twist, having first removed a larger layer of insulation than required and twist it on it. After screwing in the PPE cap, the exposed area is wrapped with electrical tape or covered with heat-shrink tubing, which creates additional compression.

However, such technology is not provided by manufacturers and requires additional actions and time.

Wago terminal blocks

When using them, the electrical contact of the circuit is created by a spring clamp controlled by a special lever.

The wire is inserted with a metal core into the terminal block socket until it stops with the lever retracted, and then fixed in it with a simple action. The created contact connection has an acceptable contact resistance and works well at rated loads. You should not count on its reliable operation under long-term overloads of more than 16 amperes.

The advantage of Vago terminal blocks is the ability to quickly rewire the circuit for its reconstruction. The wires from them in most designs can be quickly and easily removed. However, there are disposable models on sale that do not provide the function of re-breaking the created chain.

This connection method is common among our western neighbors. It is well suited for the DIYer who does everything with his own hands, but does not have sufficient practice in reliably connecting cores in other ways.

Features of connecting a flexible wire

Stranded strands are designed for use in mobile electrical appliances. They withstand bending and twisting well, but do not work well when installed in terminal blocks to create a screw or spring contact.

Under the created compression force, individual wires are deformed, and their overall twist spreads so that the total cross-sectional area of ​​the wire can decrease.

To prevent this process, metal tips with a dielectric insert of appropriate diameters are used. After installing the bare core in them, a small crimp is made, creating electrical contact.

When a stranded wire with such a tip is inserted into the terminal block, it is additionally compressed by fastening a screw or by spring force. As a result, a normal electrical contact is created from all the wires.

Only properly configured protection can prevent the consequences of undetected installation errors when switching on under load:

• circuit breakers,

To supplement the material on reliable connection of wires, in relation to home wiring conditions, the owner’s video “Tips from an Electrician” “Pros and Cons” provides information. We recommend viewing.