Detachable connections of wire cores are made using. Examples of connecting wires in home wiring

Any man strives to ensure that the electricity supply in his own home or apartment is of high quality, uninterrupted and reliable. Therefore, when carrying out electrical installation work during construction or repairs, it is necessary to correctly connect electrical wires. But in everyday life you still have to face problems when the lamp wire broke, the socket stopped working. Of course, if you have basic knowledge of electrical engineering and the ability to carry out electrical installation work, it is easy to fix all these faults yourself.

The connection of conductors made of different metals must be made taking into account all the properties of the material from which they are made. Currently, copper, aluminum and steel are used to transmit electrical energy. Each of these metals has different densities, conductivities, and resistances that are taken into account when making good electrical contact. It is also necessary to take into account the magnitude of the electrochemical potential that arises when current is applied to the metal.

Therefore, if aluminum and copper conductors are connected incorrectly, problems may occur. serious problems problems that many specialists who repair wiring in apartments encounter. Previously used in homes copper wires, which were much superior to aluminum ones in terms of electrical performance. And currently use of copper conductors faded into the background.

Aluminum, having a high level of oxidation, forms a specific film when combined, which has a fairly high electrical resistance. This property manifests itself especially in humid environments. The same film is formed on copper, only its resistance is much lower. Therefore, due to this difference in resistance, direct connection of these metals results in difficult electrical conductivity. A oxidation processes lead to sparking, heating and fire of wires.

Methods for safe contact

To create reliable contact between electrical wires, there are several methods, both using special equipment and using improvised means.

Types of wire connections:

1. Twisting (twisting) is the most common method, the use of which is desirable for temporary connections.
2. Welding is the most reliable method that ensures excellent contact of conductors. Requires welding equipment and certain skills to carry out the work.
3. Soldering - has excellent connection performance, but requires compliance with the temperature regime (not higher than 65℃).
4. Terminal blocks are a fairly simple and reliable connection.
5. Connecting wires using clamps - subject to operating conditions - allows you to get excellent contact. Installs very quickly.
6. Crimping with sleeves requires special pliers and knowledge of installation technology, but the method is very reliable.
7. Bolted connection - used in difficult situations, easy to perform and does not require special devices.

When choosing the type of connection, it is necessary to take into account: the material of the conductive part; wire section; number of conductors; type of insulation; terms of Use. Most often, the selection of the type of connection is carried out at the work site.

This technological operation is common to all methods of connecting conductors. Before combining the wires into a common electrical unit, it is necessary to strip them of the insulation layer.

The easiest way to do this work is with a mechanic's knife, but in this case there is a possibility of damage to the conductive core. To avoid this, you need to:

1. Place the wire on the table surface.
2. Press it with the index finger of your left hand.
3. Holding the knife in your right hand, cut the insulation. In this case, it is necessary to direct the blade at an angle to the cut so as not to damage the core. Otherwise, the conductor may break.
4. Using the finger of your left hand, twist the conductor one turn to cut the insulation.
5. Remove the cut piece of the insulating sheath.

Experienced electricians have in their arsenal a multifunctional tool - a stripper, which is designed for cutting cables and removing insulation. This device does not damage the core when removing insulation from a conductor of any cross-section, since it has a special calibrated recess for the required wire diameter.

The length of insulation stripping is selected in accordance with the method of connecting the conductors.

The simplest and most well-known method of connecting electrical wires is twisting them (twisting). Experienced electricians often call it the old-fashioned method.

Previously, this type of connection was used everywhere, but with increasing load in the electrical network in a modern apartment, twisting has become prohibited. However, this connection method must be studied first, since it is the main step in soldering and welding wires.

The main advantage of twisting is the absence of any material costs, since you only need pliers and a knife to remove the insulation. And of course, the advantage of twisting is the ease of its execution. Anyone who has held pliers in their hands can do this job without any problems.

Over time, the twist weakens, which is its main disadvantage. This process is connected with the fact that in any veins there is residual elastic deformation. Therefore, at the point of twisting, the contact resistance increases, which leads to weakening of the contact and heating of the conductor. It would be good if this defect is discovered in time and the junction can be redone, but a fire may occur.

But if for some reason you do not have the opportunity to use more reliable methods, then you definitely need to familiarize yourself with how to properly connect the wires to each other using the twisting method. To do this, you first need to strip the cores of 70-80 mm of insulation. Then, holding both conductors where the insulation ends, use pliers to grab the ends of the wires and rotate them clockwise. Main the condition for reliable twisting is the simultaneous rotation of the conductors, and not alternately winding them on each other.

If the diameter of the wires is small, then twisting can be done entirely by hand. With your left hand you need to hold the conductors along the cut of the insulation, and with your right hand you need to rotate the conductors by the bend (10-15 mm) clockwise. For tighter contact at the end of the rotation, you can use pliers.

The next step is to insulate the junction of the wires. For this, insulating tape is used. To ensure reliability and protect the contact from moisture, you need to wind the tape in several layers, while stepping 2-3 cm onto the wire insulation. A very good option for insulation is the use of thermal tubes; the main thing is not to forget to put it on one of the cores.

Professional electricians advise not to stop at the stage of twisting the wires, but to strengthen the joint by soldering or welding.

How to connect wires by soldering

The type of connection in which electrical wires are joined using molten solder is called soldering. This method is best applicable to wires with copper conductors, but the use of special fluxes allows you to obtain high-quality joints of other metals.

Advantages of using soldering:

• In terms of reliability, this type of connecting wires is second only to welding;
• allows you to connect both single-core and stranded wires, as well as wires with different sections;
• no maintenance of the contact point is required for the entire period of operation;
• low cost of work (flux and solder are inexpensive).

The disadvantage of soldering is considered to be rather high labor intensity. The surfaces to be soldered must be previously cleaned of oxides and tinned before twisting the wires.

An electrician must have certain qualifications and be able to use a soldering iron, because during the work it is necessary to strictly observe the temperature regime. A weakly heated or overheated contact point loses its reliability and strength.

The technological process for performing soldering looks like this:

1. The insulation is removed from the conductors by 40-50 mm.
2. Areas of exposed veins are well cleaned with sandpaper.
3. Tinning of wires is carried out. To do this, a heated soldering iron is dipped in rosin and the tip is passed several times over the cleaned surfaces.
4. The wires are twisted.
5. Place solder on the soldering iron tip and heat the twist. In this case, molten tin should fill all the gaps between the turns.
6. After cooling, the soldering is wiped with alcohol and insulated.

To create the most reliable connection of the conductors after twisting, they are additionally secured by welding. The technology for making such a contact is very similar to soldering, only here a welding machine is used instead of a soldering iron.

In terms of quality and reliability, the welding method fully meets all regulatory requirements for creating electrical contact.

When creating a connection by welding, the conductors are twisted and their tip is welded. The resulting metal ball provides a very reliable connection of the wires. At the same time, reliability is due not only to the creation of high electrical characteristics, but also mechanical ones.

The main disadvantage of this type of wire connection is the presence of a welding machine and devices for such work. In addition, it is necessary to strictly adhere to the rules of working at height and fire safety.

Sequence of wire welding:

1. We strip the conductors from insulation by 60-70 mm.
2. We clean the cores mechanically (sandpaper).
3. We twist the wires, and its length must be at least 50 mm.
4. We fix the welding grounding contact on top of the twist.
5. Lightly touch the bottom of the twist with the electrode. Wire welding occurs very quickly.
6. After the contact ball has cooled, we insulate it.

As a result of such actions, an almost solid conductor is obtained, and the contact node will have the lowest transition resistance.

For such a connection of conductors, special copper or aluminum sleeves are required, which are selected in accordance with the size of the bundle diameter. It is advisable to use the same material for the sleeves as that of the conductor.

The wires are stripped to the length of the sleeve, rolled up and placed in a tube. Then, using special pliers, the connection is pressed and insulated.

There are tube sleeves for extending conductors, that is, for attaching them longitudinally. The wires are inserted into such sleeves from different sides of the tube, then crimped individually.

Bolt method

This connection is used in electrical circuits with high voltage. Its use is suitable for switching almost any conductors.

• put the washer on the bolt;
• first conductor;
• next washer;
• second conductor;
• puck again;
• screw.

Then the assembled assembly is tightened by hand, and then pressed with a wrench or pliers.

Modern industry has mastered the production of special wire connectors, which have made work much easier and have sped up switching work:

1. Caps with built-in crimp spring. The stripped wires are inserted into such a cap and turned clockwise. With this action, the wires are securely compressed inside.
2. Terminal blocks, which have tubular brass sleeves inside. Bare wires are inserted into these sleeves and clamped with screws.
3. Self-clamping terminals The stripped wire is automatically fixed with a special plate.
4. Lever terminal blocks are considered reusable devices. Fixation of the conductor is ensured by raising and lowering the lever.

Remember that the connection of wires must always be made on de-energized electrical networks. Without knowledge of electrical engineering, it is better to entrust work involving dangerous voltage to specialists.

When performing electrical wiring, you inevitably face the need to connect sections of wires to each other. Connections are made in junction boxes that are mounted in the wall or on the wall. Usually in such a box the wires leading to the machine in the distribution panel and the wires going to the socket, lamp, switch are connected. Another wire can go in transit from our box to the next one. All connections, of course, are made in accordance with the diagram.

Wall Mounted Junction Box

So, before we run and connect the wires, let’s remember what main types of connections exist:

• twisting of wires and their further soldering or welding;
• connection using terminal blocks;
• connection using “nuts”;
• connection of neutral wires using connecting busbars;
• spring terminals type WAGO;
• use of bolted connections.
• connection using sleeves.

The good old way of joining - twisting

To twist the wires and insulate the twisted area, you don’t need anything other than pliers and electrical tape. High-quality and carefully made strands of copper wires last for several decades. Don’t forget to clean the exposed areas of the conductor core (TCC) before twisting them.

For greater reliability, the twist can be soldered using standard tin-lead solder and rosin or other flux. It is even better to pass a short-term welding current through the joint. At the end of the twist, a bead (drop) of copper is formed; such a connection will last until the insulation is destroyed. Only copper conductors can be welded and soldered. But if we look at the PUE, we will see that twisting is prohibited, especially in wooden houses and bathhouses, so twisting is done with soldering or welding.

twisting with soldering and twisting by welding

In general, it is much more difficult to achieve reliable connections for aluminum conductors than for copper. When twisting aluminum wires, due to the mechanical properties of the material, it is very easy to tear or break the exposed part of the TPG. Using screw and generally threaded connections for aluminum wires, it is necessary to periodically stretch the contacts, since the material “floats” over time, the contact resistance gradually deteriorates, and as a result, the contact may burn out and, in the worst case, a fire.

The main problem that can arise when performing conventional twisting is electrochemical corrosion when trying to connect wires made of different materials; it is especially dangerous to try to twist wires made of copper and aluminum. In practice, there are more than one cases where such connections had to be redone.

To perform twists that are homogeneous in material, PPE (connecting insulating clamp) is widely used. The PPE cap is screwed onto the wires connected together, ensuring their twisting and squeezing the exposed areas of the TPG. The insulation of such a connection is quite reliable, and certainly no worse than using electrical tape. When using PPE, it is necessary to very carefully ensure that the sizes of the cap and the connected wires match.

Terminal blocks

Connections using terminal blocks are widely used. The plastic body of the pad contains contact sleeves (usually brass) with internal threads. Reliable contact is ensured by screws that clamp the wire inserted into the sleeve.

Branch cable clamps

To reliably connect wires made of different materials and to branch wires from the main (main) line without breaking it, cable clamps (“nuts”) are used. The “nut” core consists of two pressure dies and a separating central plate. This entire structure is bolted together. The main feature of cable compression is that the connected cores contact each other only through a steel separating plate. Often, “nuts” are used when installing an input into a house or apartment to transition from the main aluminum wire to copper internal wiring.

Walnut clamp without cover "Nut" fully assembled

Connection bars

To connect a large number of working neutral or protective grounding conductors in distribution panels, busbars are widely used. The zero bus is attached to the panel structure or installed on a DIN rail through an insulating stand, the “earth” bus is attached directly to the housing. Both buses have several holes with clamping screws for connecting cores.

Grounding bus

When using screw terminals, the force with which the core is pressed against the contact weakens over time, especially in the case of contact with aluminum. The contact deteriorates and the junction begins to heat up. This leads to the need for periodic inspection and tightening of threaded contacts.

Spring terminals

Screwless spring terminals significantly speed up the installation process. Their design was developed by the German company WAGO in the fifties of the twentieth century. Terminals for construction installation based on flat spring clamps allow you to reliably connect any copper and single-core aluminum wires in any combination without the use of special tools.

WAGO 222 series

The main advantage of spring terminals is that the spring itself is always movable; spring steel clamps create a specified clamping force throughout the entire service life of the terminal. It automatically matches the cross-section of the conductor; the force is applied to the surface of the conductor without deforming it. This ensures constant contact.

Wire installation in WAGO 222 series

The use of spring terminals allows you to reduce electrical installation time (this is especially important for large volumes of work), there is a separate terminal space for each conductor, the conductors are not damaged, reliable protection is provided against accidental touching of non-insulated contacts, all connections look aesthetically pleasing and compact.

There are spring terminals with plug-in contacts (for example, WAGO terminals 773, 2273 series). These terminals can only be used for single-core wires. The bare end of the core is simply inserted into such a terminal block with little effort. To disconnect the contact, the wire is also unscrewed from the terminal block with a little force.

Even more convenient are universal terminals - “latches” (for example, WAGO terminals of the 222, 221 series). They can be used when assembling temporary circuits, since establishing and disconnecting contact takes a few seconds. These terminals allow you to connect wires of different materials and different cross-sections.

The tinned busbar ensures a permanently reliable and gas-tight connection. For example, the performance characteristics of the 221 series are 32 A/450 V and a maximum temperature of 105 °C. 221 series terminals can be used at ambient temperatures up to 85 °C.

It is recommended that before connecting the aluminum wire, fill the terminal with a special contact paste that removes the oxide film and prevents further oxidation of the wire. The WAGO product range includes terminals filled with such paste during manufacture.

There are special spring terminals for connecting lamps. Typical parameters of such terminals are that on the mounting side it is possible to connect one or two copper or aluminum single-core wires with a cross-section of up to 2.5 square meters. mm; on the luminaire side - any copper wire of the same cross-section. The rated current for copper wires is 24 A, for aluminum - 16 A.

Connecting different materials with a bolt

When connecting copper and aluminum wires, it is necessary to prevent direct contact of these metals. To do this, you can use branch cable clamps (“nuts”). Spring terminal connectors can be used. You can use a regular steel bolt onto which insulated wire ends made of different materials are wound. Between the wires, a steel washer must be placed on the bolt; it is advisable to spring it with a Grover washer for the durability of the connection.

The final view of connecting wires made of different metals

Sleeve connections

The most reliable connection method is a sleeve connection. It is necessary to select the sleeve itself for the cross-section of the wires. Place the wires on one side and the other and use special pliers to crimp the sleeve with the wires.

Crimping the sleeve with a special press

After this, the sleeve is insulated with electrical tape or heat-shrink tubing. Of course, the connection quality is good, but the work increases significantly. Moreover, it is difficult to select and buy cartridges in a store.

In the article we will talk about methods for connecting wires in junction boxes, and talk about preparing conductors for connecting household appliances and installation products.

Electrical wiring of residential premises consists of many elements, these are various current-carrying conductors (cables), protective devices, electrical installation products, and individual current consumers. In order to assemble all the components of the system into a single circuit and at the same time make the power supply functional and safe, it is necessary to qualitatively connect them together, or, as they say, switch them (switching refers to the processes that occur when electrical circuits are closed or opened).

At first glance, it may seem to an unprepared person that there shouldn’t be anything complicated here. But when working with electricians “on a whim,” it doesn’t matter whether we’re moving a single outlet, connecting a lamp, or assembling a complex control system, we take a serious risk. Experienced electricians know that electrical installation is primarily a “struggle for contact,” since it is an open circuit, and not a short circuit, that is the most common problem encountered. Obviously, the connection points in the circuit (terminals, twists) are the most vulnerable, since at these points the mechanical density of the contact can weaken (the contact area decreases), and an oxide film with a very high resistance forms on the conductors over time. Poor contact causes heating of current-carrying conductors and sparking at switching points - these are the consequences of the occurrence of transient contact resistance. Complete burnout of the wire and loss of power to the area when household appliances do not work or the light goes out is unpleasant, but the problem is solved. It’s worse if the insulation of the wires heats up and breaks down, which can lead to electric shock or fire.

Recently, the load on wiring has increased significantly, so switching is now subject to even more stringent fire and electrical safety requirements. However, if previously there were not many connection options, now reliable modern devices have appeared that make wiring easier. In addition to welding and soldering with subsequent tape insulation of the twist, PPE caps, various terminal screw and spring blocks, all kinds of insulated and open lugs, and branch clamps can be used in a household network. These products will help you efficiently connect wires in junction boxes, assemble a distribution board, connect household appliances and lighting fixtures, sockets and switches.

There are several key objective factors that influence the choice of switching method, or the use of specific devices. Let's just list the main ones:

• power and number of consumers (read: total cross-section of conductors);
• material of current-carrying conductors (copper or aluminum);
• cable type (flat or round, hard or soft stranded, single or double insulated);
• purpose of the node (group or single branch, end connection);
• the presence of movement of wires or vibrations near them;
• elevated temperature, humidity;
• indoor or outdoor use.

Connecting wires in junction boxes

According to the provisions of the PUE, branching of household network wires can only be carried out in a distribution (junction) box. During operation of the wiring, junction boxes allow you to quickly get to the ends of any individual branch and, if necessary, detect which of them is broken or has a short circuit. You can also always inspect the condition of the contacts inside the box and carry out their maintenance. Modern PVC boxes are used for open and hidden wiring; they have sufficient reliability and expanded functionality: they can be easily installed on various surfaces and are convenient for electrical installation manipulations.

In order to always have access to the connected wires, all distribution boxes are located on free sections of the walls; it is most rational to install them on the side of the corridors, for example, above the door of the powered room. Naturally, boxes cannot be tightly plastered or sewn inside building frames; the permissible decorative maximum is a thin-layer finish on top of the lid (paint, wallpaper, decorative plaster).

For the arrangement of lighting and power circuits (outputs and sockets), it is recommended to use separate distribution boxes for each room. Such divided power allows you to make the electrical wiring of your home more balanced and safe, since the “lights” and “sockets” differ in workloads and operating conditions, and they are subject to different requirements. Moreover, it is much easier to upgrade or repair the wiring later, and not always all the wires in a room can be properly laid out in one housing.

Switching wires in any distribution box can be carried out according to the same principle. In most cases, “twisting” is initially used, but simply wrapping the conductors with electrical tape is not enough - it must be reinforced with additional operations that are designed to increase the contact area of ​​the connected current-carrying conductors and reduce the oxidation of materials. Clause 2.1.21 of the PUE offers the following options:

• soldering
• welding
• crimping
• crimping (bolts, screws, etc.)

Wire crimping

The essence of this method is that twisted wires are inserted into a special metal sleeve-tip, which is compressed with hand pliers, a mechanical or hydraulic press. Crimping can be done either by local pressing or by continuous compression. This connection of wires is considered one of the most reliable. Crimping allows you to compress the cores very tightly, increasing the contact area; the mechanical strength of such switching is the highest. This method is used for both copper and aluminum wires.

The crimping process consists of several operations, each of which has its own nuances:

1. The wires are freed from insulation 20-40 mm from the edge, depending on the working length of the sleeve.
2. The veins are cleaned with a brush or emery until shiny.
3. Using pliers, a tight twist is made.
4. Based on the total twist section, a GAO sleeve with the required internal diameter is selected, as well as a suitable punch and matrix.
5. The inside of the sleeve is treated with quartz vaseline paste (if it comes “dry” from the factory).
6. The twist is inserted into the sleeve.
7. The twist is compressed using press pliers. It is necessary that the tool rig is completely closed.
8. The quality of the connection is checked - the wires should not move in the tip.
9. The sleeve of the connected conductors is wrapped in three layers of insulating tape; for a tip thickness of up to 9 mm, a polyethylene insulating cap can be used.

Conductor crimping

Crimping of conductors can be done using terminal blocks, PPE caps or WAGO clamps.

The terminal block housing is made of plastic; inside it there are sockets with threads and clamping screws. The wires can be inserted under single screws of the terminal towards each other, or one conductor passes through the entire block and is fixed with two screws. Some distribution boxes are equipped with standard terminal blocks.

A clear advantage of switching on a terminal block is the ability to connect copper and aluminum wires, which in this case do not have direct contact. The disadvantage is the need to tighten the bolt clamp if aluminum conductors are used.

PPE caps (connecting insulating clips) are also made of durable non-flammable polymer, which, being an insulator, provides mechanical and fire protection. They are forcefully wound onto the twisted conductors, then the conical metal spring located inside the cap moves apart and compresses the current-carrying conductors. As a rule, the internal cavity of the PPE is treated with a paste that prevents oxidation.

WAGO terminals for junction boxes are screwless, here the compression is performed by a spring, you only need to insert the stripped wire into the terminal. These terminal blocks are designed to connect up to eight wires with a cross-section of 1-2.5 mm 2 or three wires with a cross-section from 2.5 to 6 mm 2, while the spring acts on the conductor with a force suitable for each wire. The clamps function normally at operating currents up to 41 A for 6 squares, 32 A for 4 squares and 25 A for 2.5 squares. Interestingly, WAGO universal clamps allow you to connect wires of different sections (from 0.75 to 4 mm2) in one housing.

These devices can be designed for a hard conductor, or for a soft stranded one. Due to the fact that there is no direct contact of the connected conductors, it is possible to connect copper and aluminum wires, and there is no need to regularly check the compression of aluminum. Inside, WAGO terminal blocks also have a paste that destroys the oxide film and improves contact, however, the clamps for copper conductors are not filled with contact paste. It is very easy to work with such connecting products, they are quickly installed, without the use of additional tools, they are compact and reliable. It must be said that WAGO is not the only company producing screwless spring-loaded terminal blocks.

Whatever type of crimping device is used, it is necessary to accurately select it according to the cross-section of the individual conductor or strand, since a terminal that is too large may not provide normal contact. In this case, you cannot always trust the markings - it is better to check the compliance of fasteners and conductors on site. During installation, we recommend having an assortment of crimp terminal blocks available according to standard sizes. Please note that to work with aluminum it is necessary to use contact gel; copper and aluminum conductors cannot be connected in one twist. After crimping, it is always necessary to check the strength of fixation of the cores in the terminal.

Soldering wires

Due to the technological complexity, this connection method is used quite rarely, mainly when for some reason it is impossible to use crimping, crimping or welding. You can solder wires made of aluminum and copper, you just need to choose the right solder. A regular soldering iron is suitable for branching wires with a cross-section of up to 6-10 mm2, but larger wires will have to be heated with a portable gas burner (propane + oxygen). For soldering, it is necessary to use flux in the form of rosin or its alcohol solution.

The advantages of soldering are the high reliability of the connection compared to crimping (in particular, we have an increased contact area). This method is also quite inexpensive. The disadvantages of switching construction wires by soldering include the duration of the work and the technical complexity of the process.

The soldering of conductors looks like this:

• the wires are stripped of insulation;
• the wires are sanded with emery to a metallic shine;
• a twist is made 50-70 mm long;
• The core is heated with a torch flame or a soldering iron;
• the metal is coated with flux;
• solder is introduced into the working area or the hot twist is immersed in a bath of molten solder for 1-2 seconds;
• After cooling, the soldered twist is insulated with electrical tape or polymer caps.

Welding

Most often, electricians use contact heating welding to reliably connect wires in a distribution box. You can weld twists with a total cross-section of up to 25 mm 2 . Under the influence of an electric arc at the end of the twist, the metal of several cores fuses into a single drop, and then the current during operation of the electrical circuit does not even flow through the body of the twist, but through the formed monolith. If everything is done correctly, the connection is no less reliable than a solid wire. This method has no technological or operational disadvantages, the only thing is that you need to purchase a suitable welding machine.

Welding of copper conductors is carried out using direct or alternating current with a voltage from 12 to 36 V. If we talk about factory welding units, it is better to use inverter devices with sensitive adjustment of the welding current, which are lightweight and small in size (during operation they are sometimes worn on the shoulder) , can be powered from a household network. In addition, inverters provide good arc stability at low welding currents. Due to the high cost of inverters, very often electricians use homemade welding machines made from a transformer with a power of more than 500 W, with a secondary winding voltage of 12-36 volts. The ground and electrode holder are connected to the secondary winding. The electrode itself for welding copper conductors must be infusible - carbon, this is a factory-coated "pencil" or a home-made element from a similar material.

If a factory inverter is used for welding wires, then for wires of different sections it is recommended to set the following operating current indicators: 70-90 amperes is suitable for connecting two or three wires with a cross-section of 1.5 square meters, wires with a cross-section of 2.5 mm 2 are welded at 80-120 amperes These indicators are approximate, since the exact composition of the core may vary from one manufacturer to another - it is recommended to test the device and a certain current strength on scraps of conductors. Correctly selected indicators are when the arc is stable and the electrode on the twist does not stick.

The wire welding process includes the following operations:

• the conductors are cleared of insulation (about 40-50 mm);
• a tight twist is made with pliers, its end is trimmed so that the ends of the wires have the same length;
• a ground clamp is connected to the twist;
• the carbon electrode is brought to the end of the twist for 1-2 seconds (so that the insulation does not melt, but a solid copper ball is formed;
• after cooling, the welded twist is insulated with electrical tape, heat-shrink tubing or a plastic tip.

When connecting wires, you should follow safety precautions and take fire precautions, as for any welding work. It is recommended to use a welding mask or special glasses with a light filter; welding gloves or gloves will not be superfluous.

Connecting wires to electrical equipment terminals

Connecting household appliances and various electrical installation products is also an important stage in wiring switching. The performance of consumers, as well as user protection and fire safety, depend on the reliability of electrical connections in these nodes.

The technology for connecting current-carrying conductors to equipment is regulated by PUE, current SNiPs, as well as the “Instructions for terminating, connecting and branching aluminum and copper conductors of insulated wires and cables and connecting them to the contact terminals of electrical devices.” Just like branching conductors in distribution boxes, soldering, welding, crimping, screw or spring crimping are used for termination and connection. One method or another is selected primarily depending on the design of the equipment, as well as on the properties of the current-carrying conductor.

Screw crimping is used in most types of modern equipment. Screw terminals are found in sockets and switches, chandeliers and lamps, in various household appliances (built-in fan, air conditioner, hob). Crimp sockets are used to supply elements of the distribution board: circuit breakers, RCDs, electric meters, and switching busbars with screw terminals are also used here.

It should be noted that convenient spring-loaded terminal blocks can also be used to connect equipment. For example, very often switches are equipped with screwless terminals; WAGO produces a special series of clamps for connecting chandeliers and lamps, as well as for switching in ASUs (terminals mounted on a DIN rail).

Please note that to connect using the crimp method, soft stranded conductors must be terminated with insulated lugs (connectors). For rigid monolithic cores, connectors are not needed. If you do not use lugs, then the soft core should be tightly twisted and tinned with solder before connecting. The size of the tip is selected depending on the cross-section of the conductor, and the geometry of the contact part is selected depending on the type of terminal on the connected device and the operating features. For example, for a clamping tunnel socket, a connector in the form of a pin is used; for fixing with a nut on a bolt, a ring or fork connector is used. In turn, the fork tip is not recommended for use if the device is moving or vibration is possible in the switching area.

If it is necessary to clamp a rigid single-wire conductor (copper or aluminum) with a cross-section of up to 10 mm 2 under the bolt, then it can be bent into a ring of a suitable radius using pliers. The ring is cleaned from the oxide film with glass sandpaper or sandpaper, lubricated with quartz vaseline gel and put on the bolt (the ring should wrap around the bolt clockwise), after which it is covered with an asterisk washer (prevents the conductor from being squeezed out), a groover (springs the connection, prevents it from unwinding when vibrations), and the assembly clamp is tightened tightly with a nut. If a large cross-section core (from 10 mm2) must be clamped under the bolt, then a metal sleeve with a ring is placed on the conductor using the crimping method.

Switching wires is a very responsible job, and the process of assembling the circuit has a lot of nuances, which for convenience should be combined into one list:

1. Strip the wires using special pliers, since stripping the insulation with a knife often reduces the cross-section of the wire.
2. Always remove the oxide film from the conductor. Use glass sandpaper or sandpaper, use special liquids and contact paste.
3. Make the twist a couple of centimeters longer, and then cut off the excess.
4. Select the diameter of the sleeve or tip as accurately as possible.
5. Place the conductor under the terminal or sleeve/tip all the way to the insulation.
6. Make sure that the wire insulation does not get under the clamp.
7. If possible, insert and clamp into the tunnel screw terminal not a single soft core, but a double core.
8. When using electrical tape, wind it with overlapping turns in three layers, be sure to go to the insulating sheath of the conductor. Electrical tape can be replaced with heat shrink or plastic caps.
9. Be sure to wrap screw terminal blocks with electrical tape.
10. Always mechanically check the strength of the connection - tug on the conductors.
11. Never connect copper and aluminum directly.
12. Securely secure the cable near the patching area so that the wire is not pulled down and there is no mechanical stress on the connection.
13. Use color coding of conductors, for example, in the entire intra-house network, the brown conductor will be the phase, the blue conductor will be the neutral, and the yellow conductor will be the ground.
14. Adopt a single connection diagram for the installation of all devices (for example, the phase on the sockets is clamped on the right terminal, and the neutral - not on the left).
15. Label both ends of all wires yourself - with a ballpoint pen on the outer sheath, at a distance of 100-150 mm from the edge of the conductor, write its purpose (for example, “pink kitchen desktop” or “bedroom light”). You can also use tags or pieces of masking tape.
16. Leave a supply of wires convenient for installation. For distribution boxes, sockets and switches, the normal end length will be 100-200 mm. To switch the switchboard, you may need wires up to one meter long so that you can run some of them from the bottom of the box, and some from the top.
17. Bring external cable channels close to the distribution boxes; it is better to insert round corrugation or pipes a few millimeters into the housing.
18. We connect sockets in parallel, and switches in series. The switch must break a phase, not a zero.
19. Compress all the wires of one connected twist into a bundle and secure it with electrical tape. Inside the box, spread the insulated connections as far apart as possible.
20. Use only certified materials and specialized tools.

In conclusion, I would like to once again note the importance of high-quality performance of switching work. In fact, the technologies used are quite simple, you just need to make them a habit, and then the “installation culture” will appear by itself, and the wiring will be reliable and durable.

Requirements are requirements, and the most popular type of connection is twisting. Where quick installation is required, terminal blocks of various shapes are used. One of the types of terminal connections is spring terminals. Wago products are especially popular.

To perform a tap without breaking the line, squeezes are used, which are called nuts among electricians. It is some type of terminal connection.

Using Terminal Blocks

The terminal block consists of contacts mounted on a plate of insulating material. The contact plate has a screw on both sides with which the wire is tightened. This allows you to press a copper wire on one side of the plate, and an aluminum wire on the other side, without fear of chemical interaction between these metals.

You can connect different types of wires. On one side, a single-core wire can be attached to the plate, and on the other, a multi-core wire. Another problem that can be easily solved using a terminal block is connecting wires with different core diameters.

The terminal block can consist of one or more contact plates, which is very convenient in installation conditions. To do this, just collect the required number of plates and secure them in the right place.

Spring terminals

Terminals of this type are very similar in design to terminal blocks. The difference is that a spring-loaded plate is used as a clamp. Using spring terminals is very simple - you just need to strip the wire to the depth of the terminal.

The pressure plate is removed and the stripped wire is inserted into the terminal. The wire is inserted so that there are no exposed sections of the wire. Then the pressure plate snaps into place and the process is complete.

Spring terminals can be used to mount single-core, stranded wires and wires of different diameters. Installation of wires from different metals is allowed. The most widely used contacts are Wago contacts, which contain bimetal plates with a special contact paste against metal oxidation.

Installation of PPE caps

PPE caps are often used when installing wiring. In appearance, they are very similar to the back plastic cap of a ballpoint pen. A cone-shaped spring is placed inside it. The spring is coated with oxidation-resistant metal by anodizing.

To connect wires need to be stripped to a length of 10 - 15 mm and fold the stripped areas into one bundle. The ends of the bundle are inserted into the cap, which is then screwed onto them until it stops. The PPE cap can connect several wires, the total cross-section of which will not exceed 20 mm².

They are produced in different sizes, so choosing the ones you need is easy. The caps are color-coded, which is convenient for identifying phase or neutral wires.

PPE brand	Number and cross-section of cores in mm²	Cap color
PPE – 1	2 x 1.5	Grey
PPE – 2	3 x 1.5	Blue
PPE – 3	2 x 2.5	Orange
PPE – 4	4 x 2.5	Yellow
PPE - 5	8 x 2.5	Red

PPE caps can significantly increase installation time because this connection does not require additional insulation. The cap material is made of non-flammable material and will not cause spontaneous combustion if overheated at the junction.

The quality of connection of PPE with caps is worse than with terminals and does not allow connecting wires of different metals.

Crimping with special sleeves

Where it is necessary to create a high-quality and reliable connection, special sleeves can be used. The sleeve is a piece of copper tube of the required diameter. The diameter of the sleeve is selected depending on the total diameter of the connected wires.

The stripped ends of the wires are inserted into the sleeve and clamped. Then a heat-shrinkable tube is put on the sleeve, which insulates this sleeve. If there is no heat shrink tube, you can use cambric or electrical tape. Wires can be inserted into the sleeve from one or both sides. For crimping, they try to use special hand press pliers.

With this connection, the sleeve cannot be used twice. During repairs, it is simply thrown away. If you use hand strippers and press pliers, you can perform installation with good productivity.

Soldering or welding

Installation using soldering is not used very often. Soldering always guarantees a reliable connection. The contact has low resistance and good mechanical strength. Soldered wires are less susceptible to damage due to ingress of moisture.

To connect by soldering, it is necessary to strip the wires by 40 - 50 mm, tin with rosin and twist. Then solder is applied to the twisted ends and heated until it spreads evenly over the entire twist and flows inside. The appearance of the soldered wires should be shiny.

After soldering, the sharp ends are treated to prevent damage to the insulating material. Any available type can be used as insulation.

This connection can be considered the most labor-intensive. The soldering process requires certain skills. Installation in this way at a height using improvised means is not very convenient. When connecting by soldering, it is necessary to leave some reserve in case of repair.

In some cases, a connection using the contact welding method is used. The process itself is similar to the soldering method, but the stripped twisted wires are not coated with solder. A welding transformer is used for connection. The ends of the wires are heated until they fuse into one metal ball.

For insulation, put a heat-shrinkable tube or wrap it with electrical tape on the welded ends.

Stranding and insulation

The rules of the PUE completely reject twisting, but in practice, connecting wires by twisting is used almost everywhere. But you need to know how to twist, and then it will last for decades. To do this, strip the wires according to this calculation. That the twist should be at least 4 - 5 cm long.

The cleaned areas are cleaned of the oxide film with a knife blade or fine sandpaper. The ends of the wires are crossed at a certain angle at the end of the insulation and twisted tightly with pliers. The twist should be even and tight. From above it is insulated with existing insulation.

Twisted connections cannot be made for wires of different sections. Do not twist wires made of different metals. Twisting a single-core wire with a stranded wire is not allowed. This connection is used only where there is no fire-technical acceptance of repairs.

Walnut clamp

The nut-type branch clamp is designed for making branches from main wires without breaking. At the point where the outlet is connected, a section of insulation is removed and a “nut” is attached to this place. The clamp consists of a carbolite body and a steel clamp. The clamp consists of two plates and screws. Each plate has a recess for a certain cross-section of wire.

One plate is placed under the wire and covered with another plate on top. Both plates are clamped with screws, and between them there is a wire and a tap. To choose the right “nut” depending on the diameter of the wire, you need to use the table.

Clamp type	Line cross-section mm²	Branch section mm²	Clamp dimensions
U731M	4 – 10	1.5 – 10	42 x 41 x 31
U733M	16 – 35	1.5 – 10	42 x 41 x 31
U734M	16 – 35	16 – 25	42 x 41 x 31
U739M	4 – 10	1.5 – 2.5	42 x 36 x 23
U859M	50 – 70	4 – 35	62 x 61 x 43.5
U870M	95 – 150	16 – 50	84 x 85 x 60
U871M	95 – 150	50 – 95	84 x 85 x 60
U872M	95 — 150	95 — 120	84 x 85 x 60

To make the connection, you need to disassemble the carbolite body. It consists of two halves compressed by two retaining rings. If the rings are pryed and removed, the body will fall apart. If the wires are made of different metals, then it is necessary to use an additional plate. It will prevent contact of different metals and further oxidation process, which will worsen the contact. The screws are tightened with reasonable torque and inserted into the housing.

Using a bolt

The bolt connection is most often used when it is necessary to connect copper and aluminum wires. Stripped wires are put on a regular steel bolt, and steel washers and a Grover washer are put between them. The entire “sandwich” is pulled together and wrapped with insulating tape.

What to do if there are several wires?

To connect multiple wires, you can use a terminal block. To do this, you need to connect one half of the contact plates with one wire. The number of such plates must be equal to the number of wires. The remaining wires are attached to the opposite contacts of the plates.

You can take a terminal block with a number of plates equal to the number of wires divided in half. Then one half of the wires is clamped onto one half, and the other half onto the other half of the contacts.

Multiple wires can be connected using a bolt. Place a steel washer between the wires, and put a Grover washer under the nut.

Identical wires can be connected using a PPE cap using known technology or by welding.

What to do if the wires are of different sections?

If you need to connect wires with cores of different sections, you can use:

• Soldering or welding;
• Bolted connection;
• Connection with self-clamping terminals;
• Screw terminals;
• Branch clamp;
• Copper lugs and bolted connection.

Combining stranded and single-core products

The connection of stranded and single-core wires can be made using:

• Solder connection;
• Connection with special sleeves;
• Terminal connections;
• Connection with lugs.

How to carry out work in water and on land?

All outdoor electrical wiring must be carefully protected from moisture. For installation, it is necessary to choose cable products that are designed for such work. The cable must have at least two insulating layers. In addition to the existing insulation, the wire must be placed in a corrugation. For installation in the ground - in a pipe with sealed couplings.

All sockets, switches, lamps and other elements must be manufactured in the appropriate design. On water, only low voltage is used for power supply. All connecting elements are placed above the water level.

The connection of electrical wiring wires is important for trouble-free operation of the electrical network of the apartment and house. To connect wires correctly, you need to know about the planned network load and know how to connect wires made of different materials. Incorrect connection leads to heating of the wires and their connections.

The property of heating wires during the passage of electric current is actively used not only in everyday life, but in many areas of industry and production. For example, industrial heaters used in extruders, injection molds and molds are heated by spirals with high electrical resistance placed in a ceramic shell.

What is the problem with wire connections?

The main problem of wire connections in electrical wiring is the connection of wires or cable cores made of aluminum and copper. So what's the problem?

When copper and aluminum are twisted, a chemical compound is formed from the contact of copper and aluminum, which is often called “red death”. This connection, having a denser crystal lattice than copper and aluminum, weakens the contact of the connection.

In addition, such a connection destroys the oxide film around aluminum (Al2O3), and this provokes corrosion of the aluminum, which again leads to weakening of the contact.

This is all true, but there are some, but!

• Firstly, these processes proceed quickly only in air, with the access of moisture, hydrogen sulfide and other aggressive catalysts.
• Secondly, these processes proceed very slowly if you have well insulated the twisted copper and aluminum. Breaking contact in such a twist can take 10-20 years and the possible current in the electrical wiring of the apartment will not affect the time of destruction of the twist.

I am not writing all this to encourage you to twist aluminum and copper. No! It’s just that if, somewhere, someone did such a twist on you, there is no need to panic. I'm sure it will work for decades.

But, still, you don’t need to do such twists yourself. There are many options to make the correct connection of copper and aluminum electrical wiring wires.

Correct connection of copper and aluminum wiring wires

The most reliable connection is welding the ends of twisted wires. Welding leads to diffusion (mutual penetration) of materials into each other. In installation conditions, fusion welding using active fluxes VAMI, F-54A is applicable. (do not confuse soldering with melting).

But I repeat once again, all the costs of joining copper and aluminum by twisting, using the correct technology, are not worth it. You can use other types of wire connections, which are discussed below.

Connecting electrical wires - connection technologies

According to the PUE ed. 6 (, clause 2.1.21. Wire cores can only be connected:

• Lived by crimping the ends;
• Welding twisted wires;
• He lived by soldering;
• Using screw and bolt clamps (clamps).

By the way, speaking. There is nothing about the connection of electrical wiring in residential premises. There is paragraph 4.2.46, which prohibits twisting wires in open switchgears. That's all!

Let's continue about the permitted wire connections.

Crimping the ends of the cores to connect them

Crimping the ends of the cores is the most reliable connection of wires. True, crimping requires a special tool.

• Wire cores made of the same material are crimped.
• For crimping you need a sleeve of the required size. The size of the sleeve must exactly correspond to the total cross-section of the connected cores. The wires are stripped to the length of the sleeve plus 10 mm.
• The bare wires are inserted into the sleeve, and the sleeve is pressed with a special tool. The crimping tool is not expensive, but universal. It can be used to properly strip (remove insulation) wires and crimp sleeves of various cross-sections.

In individual houses, the crimping method is used to connect end sleeves to grounding wires and connect them to the main grounding bus through a bolted connection.

For apartments, this method is suitable for multi-core cables. Stranded cores are pressed not with sleeves, but with insulated pin sleeve lugs (NSVI).

The stranded wire is stripped, the exposed wires are twisted with fingers, inserted into the tip and the tip is crimped along its entire length. Again, for a quality connection you need a special tool.

Welding of wire and cable cores

Welding is the most complete connection of wires. When welding, the wire strands penetrate each other, forming the tightest connection.

The welding technology is as follows:

• The wires are stripped to 50-60 mm;
• Exposed wires are twisted;
• The end of the twist is bitten off;
• The earth is hooked onto the core, a coal sting is brought to the end of the twist, welding is performed for 1-2 seconds;
• The cooled connection is isolated.

Soldering wires of the same material

Aluminum wires 2.5 -10 mm are soldered. The ends of the wires are stripped, then stripped to a shine and double twisted. The twist is soldered with a propane torch.

Soldering is practically not used for apartments. It is interesting in private housing construction, when connecting power and disconnecting aluminum power wires with a cross-section of 10 mm 2 or more.

Copper wires with a cross-section of 1.5 mm are also twisted and soldered with a soldering iron. Rosin type solder is used.

Screw terminals, spring terminals and screw terminals

Screw terminals and the emerging spring terminals remain the most recommended method of connecting wires. Let's look at it in detail.

Terminal blocks white, polyethylene

This type of terminal block should be used only for connecting low-power devices, for example, lamps. The reason is this. The connection in these terminals is screw, the wire is pressed only by the surface of the screw. A separate screw presses the stranded wire very poorly, pressing the aluminum, it squeezes it, and over time such a screw connection weakens. A weakened connection leads to an increase in temperature and melting of the terminal block insulation. At low currents, of course, there will be no sparking, the connection will simply be broken and a wiring fault will appear.

Terminal blocks

Reliable connection of electrical wiring will be ensured by ebonite terminal blocks (photo). The wires are clamped with square metal washers under the screw. The connection is reliable and durable. The washers have a rounded shape, so that when tightened, the screw springs back and does not unscrew. Disadvantage: large pad size.

WAGO terminal blocks

Now about the terminals that clamp the wire strands with spring effects. The most popular of these terminals are WAGO terminals. But here, too, not everything is so simple.

WAGO terminal blocks are classified according to the rated currents that can pass through them.

The following series of WAGO terminal blocks are on sale.

• Series 221 (for a current of 32 A and conductors up to 4 mm 2), series 773 (for copper and aluminum, for a current of 25 A/16A).
• The 773 series was replaced by the 2273 series, which is more compact.
• Terminal blocks with lever control (reusable connections) differ. This is series 222, with a current of 32 Amps for 2-3-4 cores.
• Don't forget about the single-core connector, WAGO 224 series.

You can read more about the WAGO connector series in the article “WAGO Connectors”.

Twisting with caps

There are special caps for twisting wires. There are special knives on the cap sleeve that cut grooves on the twist. This enhances the adhesion of the wires and reduces their oxidation at the joints.

That's all about connecting electrical wires.

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