Correct twisting and types of connection of electrical wires. Types of connecting electrical wires in a junction box Connecting wires by twisting rules

Among the many connection methods, twisting electrical wires is the simplest and easiest to implement. This type The connection is not highly reliable; its main advantages are the speed of execution and a minimal set of tools during operation. Despite the disadvantages, twisting conductors remains popular for work at home and in the field.

What the rules say

The Electrical Installation Rules (PUE) when installing electrical wiring require connecting wires by crimping, welding, soldering, connecting clamps (screw, bolt, etc.). Single-wire wires can be connected by twisting followed by soldering.

In fact, this means that from the point of view of the PUE, twisting of wires is not allowed. If we are talking about a supervised object, the selection committee will not allow the operation of an object, electrical installation or electrical wiring made using such connections.

The reason for inadmissibility lies in low reliability. The elasticity of twisted wires weakens over time, and the metal of the conductive wires oxidizes. In this case, the quality of contact at the junction deteriorates. The increased resistance of such a section of the circuit works as a heating element, especially when high load currents flow. The conductors begin to heat up; in the worst case, melting and even fire of the insulation is possible.

The situation is worst when joining dissimilar metals such as copper and aluminum. Due to differences in physicochemical properties at the contact points, a rapid increase in contact resistance occurs. The situation gets worse in the presence of moisture. As a result, the connection of copper and aluminum wires Twisting is directly prohibited by the rules.

However, in practice, in everyday life, this method of connecting cores remains in demand as the fastest and simplest.

How to twist electrical wires correctly

If for some reason it is necessary to connect the wires by twisting, it is important to take measures to seal the connection as much as possible. First, the wires are stripped of their insulation. The specific length depends on the section than thinner wire, the shorter the length of the bare area required. On average, at 1.5 mm2, the conductor should be stripped to a length of about 5 cm. In the case of stranded wires, you should be especially careful when stripping the insulation, since individual thin strands can easily be damaged, thereby reducing the cross-section of the conductor. You can remove the insulation with a knife or use special tool for stripping wires.

The connected conductors can be of the same or different sections, single-core or multi-core. When wires are arranged in parallel, in series, or when branches are installed, twisting methods can be different; the options are shown in the figure.

The use of connecting insulating clamps (PIC) allows you to further improve the quality of the connection when the conductors are arranged in parallel.

The clamp is a cap made of fire-resistant plastic. There is a steel spring inside the cap. When the PPE is twisted, the spring compresses the wires, thereby improving the quality of contact. The outer plastic shell serves as insulation at the junction.

Anyway, correct twist electrical wires is the one that will ensure the tightest fit of the conductors to each other. For example, when connecting a thicker solid wire with multi-core, you can strengthen the junction by crimping the core itself, as shown in the photo.

Insulation

Insulation plays an important role in connection reliability. It not only protects against short circuits and accidental touches to live parts, but also serves to prevent moisture from entering them. The presence of humidity leads to accelerated oxidation of the metal, deterioration of contact with all the ensuing negative consequences.

The most common method of insulation is wrapping with insulating tape. The tape allows you to isolate connections of any configuration and complexity. Insulation tapes are manufactured for a variety of conditions, including those designed for use in high temperature environments

Recently, the use of heat shrink tubing has become increasingly popular. This is a tube made of a material that, when exposed to high temperature compresses, tightly enveloping the insulated parts.

The insulation method using heat shrink tubing requires the tube to be placed on the wire first, so it is best suited for serial arrangement of conductors. The shrinkage temperature is around 120°C. For this purpose, use a construction hair dryer, gas burner, as a last resort, a lighter or matches. It is important to monitor the temperature so as not to melt the insulation with flame or excessively hot air.

Despite all the shortcomings, the twisted connection is popular. In a situation where you need to power an electrical consumer, and the only tool you have is a knife or pliers, twisting is the only available solution. It must be said that in a dry place, a well-made and insulated twist can work for years without noticeable deterioration in properties. But still, if possible, it would be correct to use another connection method.

In the process of installing electrical wiring, especially in residential premises, it is necessary to use technologies for connecting wires and cables. This process requires some skills and knowledge. After all, an incorrect connection can lead to irreversible processes. Disruption of the general power supply and fires may occur. The fact is that a carelessly executed connection of multi-core wires can lead to a fire, which in turn leads to a threat to the life and health of people. Requirements for installation of wiring in residential buildings are prescribed in the Rules for Electrical Installations, abbreviated as PUE. The PUE allows the use of electrical wiring made only with copper wires in residential premises. The connection of stranded and single-core wires is permitted only by crimping, welding, soldering or using crimps. In compression, the connection is made mechanically, using screws or bolts and clamps.

Various twist options

Unprofessional connection. This is a twisting of a stranded wire with a solid one. This type of connection is not provided for by the rules, and if such a connection of wires is detected admissions committee, then the object will simply not be accepted for operation.

Twisting a stranded copper wire in a steamed box is used as an intermediate operation before soldering or welding the joint and it is necessary to solder or make crimp connections.

However, twisting is still used and here you need to know how to properly twist stranded wires. It is often used in emergency cases when it is not possible to make a professional connection and the service life of such a connection will be short. And yet, twisting can be temporarily used only for open wiring, so that you can always inspect the connection point.

Bad wire connection

There are several types of twists. When twisting, it is necessary to achieve good electrical contact, as well as create mechanical tensile strength. Before you start connecting the wires, they should be prepared. Wire preparation is carried out in the following sequence:

The insulation is removed from the wire at the junction. The insulation is removed in such a way as not to damage the wire core. If a cut appears on the wire core, it may break at this point;
the exposed area of the wire is degreased. To do this, wipe it with a rag soaked in acetone;
to create good contact, the degreased section of the wire is stripped sandpaper to a metallic shine;
After connection, the wire insulation must be restored. Insulating tape or heat-shrinkable tubing can be used for this.

In practice, several types of twists are used:

Connecting the wire to the main

Connection of stranded and solid copper wire

other various options connections.

In detail, about methods of connecting single-core wires

Professional connection

Let's consider various options for reliable connection technology: soldering, crimping, welding and terminal connection of wires. You will avoid unreliable twisting when installing soldered boxes and other connections.

Soldering wires

Connecting stranded and single-core copper wires by soldering is one of the reliable methods. With this connection, good electrical contact is created, and the joint is mechanically resistant to tensile loads. This method can be used when: splicing two damaged wires, extending wires, moving sockets or switches. Wires connected in this way can be used in hidden wiring. If the connection point is well insulated, then such a wire is not inferior to a solid section.

The technology for such a connection is as follows:

the preparation of the wires is carried out in the same sequence as before the start of twisting;
cleaning sections of wires to a metallic shine;
coating joints with solder (servicing);
the wires are connected using one of the types of twisting;
wires connected by twisting are soldered with solder;
The soldering area is treated with emery cloth. There should be no burrs at the soldering site that could damage the insulation;
the connection point is carefully insulated.

The wires connected in this way can be placed under the plaster. For reliability, the connection point should be placed in a polyvinyl chloride tube.

Welding method

Welding belongs to the category of permanent connections. This type is the most reliable. It is with this method that the connection section acquires solidity. The contact resistance and mechanical strength of the connection section are no different from a solid wire. Welding is carried out using both direct and alternating current.

Used for professional wire welding Various types welding machines, but the most widely used devices are inverter current devices. These devices are mobile, they can be easily carried on the electrician’s shoulder, and are small in size.

Inverter devices have a wide range of operating current regulation. Welding arc easily ignites even at low operating currents, and is stable during the entire welding period.

Except welding machine for welding copper wires It is also necessary to have carbon, copper-coated electrodes.

Welding technology consists of several simple operations. First, the insulation is removed from the wire. Then, using the technology described above, the wires are twisted. Twisted wires are straightened by cutting their ends. To avoid overheating the wires and their insulation, it is necessary to remove heat during the soldering process. For this, a special clamp is used, which is connected to one of the poles of the welding machine. Welding is carried out by touching the ends of the wires with a working electrode, which is held in a welding holder connected to the other pole of the welding machine.

Crimping

When crimping, the wires are placed in special mounting sleeves, which are made of the same material as the wires. In this case, made of copper. The sleeves are then compressed with a special tool. When the sleeve is compressed, the wires deform. When deformed, the wires are tightly compressed with each other. When pressed locally, the wires are deformed in such a way that their individual points penetrate into each other's body. In this way, reliable electrical contact is created and the joint becomes mechanically strong. Crimping is used to connect wires that are placed in junction boxes and electrical cabinets.

To perform crimping, special mounting pliers are used. For connecting wires when installing wiring in residential premises, crimping pliers model PK-16 have become widely popular. To connect copper wires, connecting copper sleeves of the GM type are used. They are made of copper and are red in color.

To ensure that the junction does not come into contact with oxygen, it is preserved with special technical petroleum jelly. Thus, the connection point is isolated from harmful effects environment. The wires will not oxidize and the connection will last a long time. The connection point can also be sealed with heat-shrinkable tubing.

Threaded connection

Twisting of stranded wires using the braiding and bolt clamping method

This type of connection, the connection of single-core and stranded wires, belongs to the category of detachable connections. For this purpose, special terminal blocks are used, consisting of both a housing and built-in devices designed for screw clamping of the wire. For a reliable connection, it is necessary to communicate or tin the wire. They are most widely used when connecting end consumers. (lamps and chandeliers)

Self-clamping terminal block Vago

Used to connect wires with a cross-section of no more than 2.5 mm 2. Using this type of terminal block, you can simultaneously connect up to 8 wires. They are used to connect wires in electrical cabinets. Mainly used for light distribution. In the socket group under heavy loads, use more reliable connection options.

In a field such as electricity, all work must be carried out strictly, accurately and without a single mistake. Some people want to figure out such work on their own, not trusting third parties to carry out a responsible mission. Today we will talk about how to properly connect wires in distribution box. The work must be done efficiently, because not only the performance of electrical appliances in the house, but also the fire safety of the premises depends on it.

About the distribution box

In an apartment or house, the wires are routed from the electrical panel according to different rooms. There are usually several connection points: switch, sockets, and so on. In order for all the wires to be collected in one place, distribution boxes were created. They carry wiring from sockets, switches and are connected in a hollow housing.

So that during repairs you do not have to look for where the wires are hidden in the walls, electrical wiring is laid on the basis of special rules prescribed in the PUE (Electrical Installation Rules).

Distribution boxes are classified according to the type of fastening. So, there are boxes for external mounting and indoor installation. For the second option, you need to prepare a hole in the wall into which the box will be inserted. As a result, the box lid is located flush with the wall. Often the cover is hidden with wallpaper or plastic during repairs. As a last resort, an outer box is used, which is attached directly to the wall.

There are round or rectangular junction boxes. In any case, there will be at least 4 exits. Each outlet has a fitting or thread to which a corrugated tube is attached. This is done to quickly replace the wire. The old wire is pulled out and new wiring is laid. It is not recommended to lay the cable in a groove on the wall. If the electrical wiring burns out, you will have to dig into the wall and disturb the finish in order to carry out repair work.

What are distribution boxes for?

There are many factors that speak in favor of the existence of junction boxes:

The power system can be repaired in a matter of hours. All connections are accessible, you can easily find the area where the wires have burned out. If the cable was laid in special channels (corrugated tube, for example), then the failed cable can be replaced in an hour;
Connections can be inspected at any time. As a rule, wiring problems occur at the connection points. If the socket or switch does not work, but there is voltage in the network, first check the quality of the connection in the junction box;
is created highest level fire safety. It is believed that dangerous places- these are connections. Using a box will keep them in one place.
minimal time and financial costs when repairing wiring. There is no need to look for broken wires in the walls.

Connecting the wires in the box

There are several ways in which conductor connections can be made in junction boxes. Note that there are simple and complex ways, however, when correct execution all options will ensure reliability of electrical wiring.

Method number 1. Twisting method

It is believed that the twisting method is used by amateurs. At the same time, this is one of the most reliable and proven options. PUE do not recommend using twisting, since the contact between the wires is unreliable. As a result, the conductors may overheat, putting the room at risk of fire. However, twisting can be used as a temporary measure, for example, when testing an assembled circuit.

Method number 2. Mounting caps - PPE

Very often, special caps are used for twisting conductors. As a result, it is possible to obtain reliable connection, with good contact. The outer shell of the cap is plastic (the material is not flammable), and the inside has metal part with a cone-shaped thread. The insert increases the contact surface, improving the electrical parameters of twisting. Most often, thick conductors are connected using caps (no soldering required).

It is necessary to remove the insulation from the wire by 2 centimeters, slightly twist the wires. When the cap is put on, it must be turned with force. At this point the connection can be considered ready.

Before making the connection, you need to count the number of wires. Based on the data obtained (cross-section), a specific type of cap is selected. The advantages of twisting using plastic caps are that you do not need to spend a lot of time, as with conventional twisting. In addition, the connection is compact.

Method No. 3. Connecting conductors by soldering

If you have a soldering iron on your household and you know how to work with it, then the wires can be connected by soldering. Before connecting the wires, they need to be tinned. Soldering flux or rosin is applied to the conductor. Next, the heated tip of the soldering iron is immersed in rosin and passed along the wire several times. A reddish coating should appear.

After the rosin dries, the wires are twisted. Using a soldering iron, tin is taken and the twist is heated until tin flows between the turns. The end result is a high-quality connection with excellent contact. However, electricians are not very fond of using this connection method. The fact is that it takes a lot of time to prepare. However, if you are doing the work for yourself, you should not spare any effort or time.

Method number 4. Welding cores

Using an inverter welding machine, you can connect wires. Welding is used over twisting. You need to set the welding current parameters on the inverter. There are certain standards for different connections:

- conductor with a cross section of 1.5 sq. mm - 30 A;

- conductor with a cross section of 2.5 sq. mm - 50A.

If the conductor is copper, then a graphite electrode is used for welding. On top part The resulting twist is connected to the grounding from the welding machine. An electrode is brought from below the twist and an arc is ignited. The electrode is applied to the twist for a couple of seconds. After some time, the connection will cool down, then it can be insulated.

Read also: Hidden electrical wiring in a wooden house

Method No. 5. Terminal blocks

Another option for connecting conductors in a box is using terminal blocks. There are several types of pads: screw, with clamps, but the principle of the device is identical. The most common is a block with a copper plate for attaching wires. By inserting several wires into a special connector, they can be reliably connected. Installation using a clamp terminal makes the connection very simple.

In screw terminals, the terminal blocks are placed in a plastic housing. There are open and closed type. Closed pads are a new generation invention. To make a connection, wires are inserted into the socket and clamped with a screw (using a screwdriver).

However, terminal connections have a disadvantage. It lies in the fact that it is inconvenient to connect several conductors together. The contacts are arranged in pairs. And if you need to connect more than three wires, then several branches are squeezed into one socket, which is very difficult. At the same time, such connections make it possible to operate branches with high current consumption.

Another type of terminals is Wago terminals. Today two types of terminals are in demand:

— terminals with a flat-spring mechanism. Sometimes they are called disposable, since it is impossible to reuse the terminals - the quality of the connection deteriorates. Inside the terminal there is a plate with spring petals. As soon as the conductor is inserted (it should only be single-core), the petal is pressed out and the wire is clamped. The conductor cuts into the metal. If you pull out the conductor by force, then the petal will not take its previous shape.

Some terminal connections contain wiring paste inside. This connection is used if you need to connect copper and aluminum wire. The paste protects metals from oxidation, protecting conductors;

- universal terminals with a lever mechanism - this is the most best view connector. The wire, stripped of insulation, is inserted into the terminal and a small lever is clamped. At this point the connection is considered complete. And if you need to reconnect, add contacts, lift the lever and pull out the wire. The pads can be operated at low current (up to 24 A - with a cross-section of 1.5 sq. mm) and at high current (32 A - with a conductor cross-section of 2.5 sq. mm). If wires are connected through which a current higher than that specified will flow, then a different type of connection must be used.

Method number 6. Crimping

The wires in the box can only be connected by crimping using special pliers and a metal sleeve. A sleeve is put on the twist, after which it is clamped with pliers. Just this method Suitable for connecting conductors with heavy loads.

Method No. 7. Bolted connection

Connecting multiple wires using bolts is easy and effective method connections. To complete the work, you need to take a bolt and several washers with a nut.

It is not enough to know how to connect the wires in a junction box. You need to know which conductors are connected to each other. So, a washer is put on the bolt thread. The core is screwed on, the second washer is put on, and then - next vein. At the end, put on the third washer and press the connection with a nut. The node is closed with insulation.

There are several advantages bolted connection conductors:

- ease of work;

— low cost;

- the ability to connect conductors made of different metals (for example, aluminum and copper).

However, there are also disadvantages:

— fixation of wires is not of high quality;

- to hide the bolt you need to use a lot of insulation;

Twisting of wires is used to provide connections and branches during electrical installation operations. Contacts with this method of switching must be reliable. Carrying out work on wiring of all types - in everyday life or in industry - is subject to a collection of requirements and rules on how to properly twist wires. They say that it is impossible for additional resistance to appear at the points of contact between the cores. Neglecting this rule will lead to heating of the contact point.

The connection is made in accordance with electrical safety standards using similar methods:

Twists.
Welding.
Soldering.
Screw clamp.
Terminal blocks and blocks.
Self-clamping express terminals.
PPE caps.

Connecting wires by twisting implies the advantages and disadvantages of the method. There is a PUE regulation prohibiting such an operation. But despite this, twisting is often used.

Twisting of contacts occurs during rough installation. This is explained by the need to establish the fact correct operation already installed connections. Check the integrity of electrical lines, make the necessary corrections, install additional devices:

switching structures;
simple and special sockets;
equipment for voltage conversion and stabilization;
rectifiers;
metering devices.

At the end preliminary work fully assembled circuit passes the functionality test. In case of incorrect operation of equipment, lack of electricity determine the cause and area of damage. We have to replace faulty components and twist the wires correctly.

Correct twisting of the wires makes it possible to quickly restore the power supply. Depending on the situation, they decide what to do with the elements of annexation:

The finished combination remains.
Improves.
It is replaced with a new one, with a different way of tying the cores.
A basic set of tools for wire manipulation. It is easy to carry out the work in the field in the absence of powerful consumers.

Therefore, it is worthwhile to provide for the maximum number of connected devices, decide how to properly twist the wires, calculate the appropriate cable cross-section, and further develop the power system in the event of an increase in the number of consumers. Then the mounted solder will serve reliably for more than one year.

Twisting cable strands to connect pieces of wiring to each other appeared immediately after the discovery of electricity. At first, this method suited everyone. But time does not stand still, new electrical equipment has appeared, the need for development has increased energy networks with increased power and current. The question arose of how to properly twist the wires in the increasingly complex realities. The twists no longer guarantee uninterrupted operation under such conditions. But at the household level it is widely used and meets the requirements of networks with low load.

Pros and cons of twists

The advantages of a braided connection are:

twisting speed;
long service life with high-quality installation;
does not require the use of complex tools;
ideally serves signaling networks where there is no powerful electrical equipment;
if necessary, the contact area can be additionally stretched or soldered;
is inexpensive;
the tap contains two to four branches simultaneously;
connection is repeated if there is an error or careless execution.

There are also many disadvantages:

high-quality insulation;
not intended for use in power networks;
inconvenient way to assemble wires;
when heated, a fire occurs;
voltage drop associated with feeder overloads.

Twisting wires with different cores

Such combinations are strictly prohibited for use. It is unacceptable to combine copper and aluminum wire! When touched, these metals enter into chemical reaction oxidation, galvanized . The contact connection is destroyed. As the load on the chain increases, weld erosion accelerates. Connecting in such conditions leads to sad results:

heating, sparking and, as a result, fire;
weakening of contact at the adhesion point;
the size of the contact space is reduced;
power surges in a section of the chain disrupt thermal equilibrium and destroy twisting.

Oxide appearance

The influence of air on the conductors oxidizes the junction. For copper and aluminum conductors, such an aggressive environment shortens their service life. The use of expensive metals such as silver or gold in conventional schemes it is not economically feasible. The problem is solved by insulating the strands with high-quality dielectric material with the right methods execution. Such measures prolong the trouble-free operation of the soldering point and the entire circuit.

Resistance at the place where the wires are combined

The result of weak contact between the cable cores is an increase in resistance in this place. Heating appears in the transition space and destruction of the entire connecting circuit. Tight connection of the wires will reduce such risks.

Types of connections in electrical circuits

Twists are classified according to the material of manufacture of the veins involved in the operation, their types, and the method of twisting. The cross-sectional areas and permissible load must be identical.

Wires with copper conductors allow repeated, up to ten times, torsion without compromising strength and contact. They easily also suitable for triple-quadruple connections. Aluminum cable is not as resistant to mechanical stress. One or two attempts at gossip - and he breaks off.

Cable cores can be single or multi-wire. The twisting method must be found taking this feature into account.

For temporary or mobile wiring, choose a more reusable twisted soft cord. The stationary and final electrical circuit consists of a monolithic core.

Connecting multi-wire cables is allowed. The directories contain data for all types. Following the numbers, materials are selected for installation from wires with different combinations lived It is necessary to take into account the cross section according to the current rating. The methods of weaving such endings do not differ.

The connection of wires will last for many years if the exact manufacturing procedure is followed.

We do this with the following veins.

The TU cambric is moved to the joint and heated until it is monolithically applied to the twisted area. In the absence of a tube, insulating tape is used. It is applied in three to four layers with a full overlap.

With absence special devices To splice cables we use twisting. The main requirement is the maximum contact area of the cores at the point of alignment. After stripping, we twist each wire at the sheath by one centimeter. We fluff out the bare ends into the hairs. Manipulation is performed with each contact.

Serial connection is made by combining counter beams one into another so that the wiring of the cores got mixed up with each other. Twisting is done from both sides in opposite directions.

When installed in parallel, the manipulations are close. The wires are arranged like a house and the fluffy corollas are braided. The connections are sealed with pliers and insulated.

Most easy method soldering of single-wire conductors is called parallel. The wires are brought together at an arbitrary angle, the stripped areas are twisted away from the point of adhesion.

To build up using a simple sequential interweaving method, the bare wires are bent, moved towards each other until they intersect and twisted with a screw in opposite directions.

When one wire, before connection, is bent and curled around the second in 2 places (at the insulation and in the area of its bent edge), the cable is spliced by parallel intersection with the gutter.

Similar consistent Twisting is done with braiding of both cores. Two twisted spots are formed at the base of the insulating layer.

Connection with the assistance of a bandage is required when working with a rigid wire or cable with a large cross-section. This technique also has parallel and sequential versions. A core is pre-prepared from a monolithic wire of a thinner cross-section, soft and made of a material similar to the main cable. The stripped ends are bent at right angles and brought closer to each other. The prepared bandage core wraps around them in uniform turns.

The connection of an additional wire and a branch for each option occurs in a parallel way. The branching of the bandage differs in that, that only the attached process is wrapped.

With the intensive development of electronic technology, the load on Electricity of the net increases. Requirements for the reliability of soldering of current supply branches are also growing. The twisting method is gradually becoming a thing of the past. Well this is noticeable on production areas, where installation is carried out using progressive methods, and outdated joints are replaced.

No matter how common various clamps and terminals have become recently, the most popular method of connecting wires is simple twisting. However, you should know that electrical installation rules prohibit the use of twisting in pure form(i.e. no further soldering or welding of the contact). You can increase the “legality” of twisting with the help of PPE. You make a twist, and on top of it you screw the PPE (connecting insulating clip).

It creates sufficient contact density and different loads and temperature changes, does not allow the contact to weaken. Choose PPE the right size, quantity and quality with free delivery is possible.

Types of twists. Errors when twisting

Firstly, remember that wires come in aluminum and copper. Copper wires are divided into monocore (one solid core) and multicore (flexible).

Monocores are used for stationary connection of equipment. Once I laid it under the plaster, behind the drywall and forgot about them. There is no longer any need to move or bend such wiring.

Multi-core cables are used for mobile devices or temporary connection of electrical equipment. Where wiring constantly needs to be moved from place to place, its location must be changed. These are home carriers, Appliances plugged into sockets.

They are also used in the assembly of switchboards, where there is a shortage of free space, and the conductors have to be significantly bent in order to be inserted into the terminals of the devices.

Let's first consider how to properly twist wires from a single core. The process here is not complicated and is known to everyone. Take two wires, strip them at the ends and begin to twist each other.

The Chinese even came up with an assistant attachment in this matter to automate the work.

Main features and rules:

⚡ wires must be made of the same material (copper or aluminum)
⚡ strip the core at least 3-4 cm, thereby increasing usable area contact
⚡ wires are laid parallel to each other
⚡ both wires must be twisted evenly together
⚡ When twisting, use some pliers to hold the place where you start stripping the insulation, and use the other to twist at the end. The insulated parts of the conductors must not be twisted together.
⚡ the number of turns that should end up being five or more

Twists of aluminum and copper wires are performed in the same way. The difference is that you can unscrew and tighten the copper ones several times, and the aluminum ones 1-2 times. After which they will break off.

What if you need to twist more than two wires, say 4-5? The process is no different:

⚡ slowly twist the wires with your hands, only giving them the shape of the future twist
⚡ take two pliers and, holding the twist at first, tighten the wires at the end
⚡ the length of the stripped areas should also be 3-4cm

There are situations when it is necessary for twisting to take as long as possible less space. Either there is not enough space in the junction box, or it must then be pulled through a narrow hole. In this case, the technology is slightly different.

⚡ place the stripped wire strands crosswise in the middle of the stripping area
⚡ and begin to twist them so that the ends after folding are equidistant from each other

In terms of quality and reliability, such twists are inferior to conventional ones.

Twisting copper wire with aluminum

Directly twist copper wire and aluminum is not allowed. Such a connection will oxidize and subsequently can lead, at best, to burnout of the contact or, at worst, to a fire. In such cases, you need to use either connectors, or use a third metal - steel, as a spacer between copper and aluminum.

Take a simple bolt with a nut and washer. The stripped wires are shaped into a ring at the end. And these rings fit on the bolt. Moreover, the wire of the ring should bend in the direction of the bolt thread.

The aluminum core is clamped with a steel washer, and a copper washer is placed on top of this washer. After which the contact is tightened with another washer and nut. That is, to create normal contact copper conductor and aluminum, you will need at least a bolt with a nut and 3 steel washers.

Twisting stranded wires

You can apply the previous descriptions of work for such conductors, but this will not provide reliable mechanical contact. Therefore, proceed as follows.