This article has a somewhat provocative title. I am sure that there will immediately be people who will write instructively, saying that twisting is illegal and wire twisting is prohibited according to the PUE.

Nobody argues with this. If it were not for the fact that, despite everything that is written in the PUE, the vast majority of wire connections on the territory of the former large Soviet country are still made on twists.

I won't claim that it's very good wire twist- this is the most reliable and high-quality way to connect wires, although they constantly try to prove it to me. It seems that someone even measured and compared the voltage drop on the twist and on the whole piece of wire, so it turned out to be less on the twist. Perhaps this is something from the field of mythology among electricians. We will simply proceed from the fact that good twisting can be called one of the stages and a very important element of such methods of connecting wires, such as soldering or welding.

Before discussing further about the correct twist, let's dwell on what will happen if the wires are connected just like that, without technology, "how it happened." In this case, at the point of contact of the two wires occurs. There are two reasons for this - a decrease in the cross-sectional area of ​​\u200b\u200bthe wire at the point of contact (mainly due to microprotrusions during connection) and the presence of an oxide film on the wire cores.

oxide film- the result of the interaction of the atoms of the metal of which the core consists with oxygen in the air. Such an oxide film has a very decent resistivity. The oxide film is absent only in noble metals - gold, platinum, etc. (that's why they are "noble", that they do not react with anyone). In silver, the resistivity of the oxide film is the same as that of the metal itself, so silver is actively used in the contacts of various electrical devices.

When the wire is heated by the current passing through it, the transient contact resistance increases even more, because. the generated heat is not completely dissipated in environment, and also heats up the wire itself, including the twist.

As a result, all this can lead to an avalanche-like process, when the place of twisting heats up more and more. Here you have one of the causes of fires due to the so-called "malfunctions in the wiring."

I met one case when an aluminum twist in a neighbor's dacha stood for only one day. The reason for this is not only the presence of poor-quality twisting, but also the material of the conductive core of the wire. already posted on the site.

The most interesting thing is that no circuit breakers and fuses in the electrical panel will help in this case, because. they respond to an increase in current in the circuit. In our case, the current does not change, it just heats up the place of contact of the two wires more and more.

Based on this, we can conclude that a good twist of wires is necessary, first of all, so that the contact contact resistance always remains stable and does not change over time.

So, what does it take to make a good twist of wires?

First you need to remove the insulation without damaging the wire strands. We clean the bare area of ​​\u200b\u200bthe core from dirt with a clean rag soaked in acetone or white spirit. Then we clean the wires with a metal brush or sandpaper to a metallic sheen.

Next, we twist the stripped veins with two pliers. To do this, we bend the ends of the cores at an angle of 90 ° at a distance equal to 7-10 diameters of the core from the insulation cut, and wind them up for each other. We wind 5-7 turns of one core onto another with pliers.

We wind 5-7 turns of another core and seal the connection with pliers, i.e. we tighten the coils of cores with two pliers in opposite directions. Then tightly bend the ends of the wires.

In order to make a branch, it is necessary to wind 10-15 turns of the branch core around the main core. Seal the branch with two pliers, tightening the turns of the core by moving them in opposite directions. Then tightly bend the end of the branch core. After all these operations, the twisting will be mechanically strong and reliable.

There are many other ways to connect wires with a twist. All these methods are given even characteristic names.

For example, here are the methods shown in one well-known book for young electricians:

The option that I described in this article, using two pliers, has been tested by practice and has never failed itself.

After creating a high-quality twist, the wires can be soldered (little used due to labor intensity), welded (in one of the articles on the site it was somehow proved that).

A good twist is also needed, for example, for a more modern and less time-consuming method of connecting wires - when using heat shrink tubing, which is a good alternative to duct tape.

By appearance it looks like a regular cambric, which is put on with a margin in both directions. Then the heat shrink tube heats up (you can use a regular lighter for this, but it is better to use an electric hair dryer), tightly wraps around the cable and insulates it securely.

Do your twists right!

If you have your favorite wire connection options - share and tell us about it in the comments to the article!

No matter how common various clamps and terminals have been lately, the most popular way to connect wires is elementary twisting. However, you should be aware that electrical installation regulations prohibit the use of twisting in pure(that is, without further soldering or contact welding). You can increase the "legality" of twisting with the help of PPE. You make a twist, and on top of it you wind PPE (connecting insulating clamp).

It creates a sufficient contact density and, under different loads and temperature differences, does not allow the contact to weaken. You can choose PPE of the right size, quantity and quality with free delivery.

Types of twists. Twisting errors

First, remember that the wires are aluminum and copper. Copper wires are divided into solid (one solid core) and stranded (flexible).

Monocore is used for stationary connection of equipment. Once laid under the plaster, behind the drywall and forgot about them. Wiggling and bending such wiring is no longer required.

Stranded ones are used for mobile devices or temporary connection of electrical equipment. Where the wiring constantly needs to be moved from place to place, change its location. These are home carriers. Appliances plugged into sockets. They are also used in the assembly of switchboards, where there is a shortage in free space, and the cores have to be significantly bent in order to lead the devices into the terminals.

Consider first how to properly twist the wires from the monocore. The process here is not intricate and is known to everyone. Two wires are taken, stripped at the ends and begin to twist together.

The main features and rules in this process:

• ⚡ wires must be of the same material (copper or aluminum)
• ⚡ clean the core by at least 3-4 cm, thereby increasing the usable contact area
• ⚡ wires run parallel to each other
• ⚡ both wires must be twisted evenly among themselves
• ⚡ when twisting with some pliers, hold the place where you start stripping the insulation, and twist at the end with others. The insulated parts of the conductors must not be twisted together.
• ⚡ the number of turns that should be obtained in the end - from five or more

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

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

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

There are situations when it is necessary that the twist takes up as little space as possible. 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.

• ⚡ put the stripped strands of wires cross on the cross, in the middle of the stripping place
• ⚡ 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.

Stranding copper wire with aluminum

It is impossible to twist copper wire and aluminum directly. 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 gasket between copper and aluminum.

A simple bolt with a nut and washer is taken. The stripped wires are shaped like a ring at the end. And these rings are put on a bolt. Moreover, the wire of the ring must bend in the direction of the thread of the bolt. The aluminum core is clamped with a steel washer, and a copper one is superimposed on top of this washer. After that, the contact is pulled together with another washer with a nut. That is, to create a normal contact between a copper conductor and an aluminum one, you will need at least a bolt with a nut and 3 steel washers.

Stranded wire twisting

It is possible to apply the previous job descriptions for such strands, but this will not give reliable mechanical contact. Therefore, proceed as follows:

• ⚡ stranded wires are fluffed (the cores are bred on the sides) and are divided into two "pigtails". You can make several braids, depending on the cross section of the wire.
• ⚡ the wires are superimposed one on top of the other and twisted one pigtail from each wire to each other
• ⚡ at the end, two "braids" obtained from four are woven into one solid twist
• ⚡ the result is a reliable twist with good mechanical contact

Recall that the twisting of wires when connecting two sections of the electrical network is an operation prohibited by the PUE. But, as practice shows, twists, as they did, they do, and nothing can be done about it. They are used by both ordinary people and experienced electricians. Of course, it cannot be argued that even the best twist is the most reliable contact, but we will assume that this type of connection will be, as it were, the first stage in the process of soldering or welding. So, our task is to consider the question of how the twisting of wires is done correctly.

There are several types of wire twists that guarantee high quality contact. And if this type of connection is carried out “but only as”, then there is a high probability that the so-called transitional contact voltage. There are two reasons for this:

• at the points of contact between two wires, the contact area decreases due to the formation of bulges of the wires themselves during their twisting;
• an oxide film will begin to form on bare wires, which will be an insurmountable barrier to the passage electric current.

It must be added that all metals, except noble ones, have an oxide film. That is why very often contacts in electrics and radio electronics are most often made of silver.

It is clear that the contact resistance leads to the fact that the connection of the two wires will begin to heat up. And this again leads to an increase in resistance. At the same time, heat inside the insulation is practically not removed, which leads to an increase in the temperature of both wires and twisting. This process, like a geometric progression, increases like an avalanche. So not far from the fire, which is usually stated as a "malfunction in the wiring."

But the most interesting thing is that no protective devices react to this. It means circuit breakers and various fuses. And the thing is that these devices respond to an increase in load, which in this situation is not in the network. The current strength is still the same without changes, the bad contact just heats up.

From the foregoing, we can conclude that a well-made twist is necessary for only one single purpose - not to change the value of the transient contact resistance. This figure should remain stable.

Before proceeding to the analysis of the position, how to twist the wires correctly, it is necessary to prepare the wires themselves.

1. First, the insulation is removed from the cores.
2. If a metal conductor dirty, it must be cleaned with a clean cloth soaked in solvent or white spirit.
3. After that, the bare wire itself must be cleaned to a metallic sheen. This can be done with sandpaper or a wire brush.

Then you can start twisting, for which you need to use pliers.

The simplest twist is winding one wire onto another. To do this, one end must be bent at an angle of 90º, approximately at a distance from the edge of the insulation, equal to 7-10 core diameters. Then, using pliers, make 5-8 turns around the connected core. In this case, the turns are compacted by pressing the tool (it is not necessary to press very hard). The end of the second wire must be bent in the opposite direction and wound in the same way, followed by clamping the pliers.

In order not to deal with each species separately, we offer a figure where these species are already shown.

As mentioned above, this is the first stage of connecting two electrical sections. After that, the connection can be soldered or boiled. Many do not do this, but it is soldering or welding that is the key to a high quality joint. Although it should be noted that both of these processes are serious things. Not everyone can do it on their own. Therefore, most often, insulating PPE caps are put on the twist.

PPE caps are a kind of insulation, which is selected according to the cross section of the twist. They also create a slight pressure that presses two elements inside the twist of wires to each other. In addition, PPE caps are selected by color, designating phase, zero and ground loops according to the PUE, which makes it easy to recognize loops in a bundle of cables laid according to the building scheme. They also isolate each area.

We will not prove to you that the twisting of wires is good way connections. Yes, it can be done with high quality and insulated. It is also great as a temporary option. But according to the rules for electrical installations (PUE), in order to connect a wire or cable, ordinary twists are not recommended. Nevertheless, we will talk about it, and very detailed. Firstly, because, contrary to the PUE, most of the connections are still made by this old "grandfather" method. Secondly, because correct twisting is the main step in the most reliable ways wire connections - welding and soldering.

Why do you need a good twist?

Imagine that two wires to be connected are twisted together just as if. Those who are familiar with electrical engineering know that a contact resistance arises at the point of contact between two conductors. Its value depends on two factors:

• surface area at the point of contact;
• the presence of an oxide film on the conductors.

To perform twisting, the core is exposed, the metal interacts with atmospheric oxygen, as a result of which the surface of the conductor is covered with an oxide film, which has a decent value of resistivity.

example of poor-quality twisting: the twisting point heats up, the insulation melts

Accordingly, if the twisting is performed poorly, the contact resistance increases, which in turn, when an electric current passes through the junction, will cause heating. As a result, the place of twisting may heat up so that the electrical wiring will ignite. Surely everyone had to hear the phrase in their life that the fire occurred due to a malfunction in the electrical network.

To prevent this from happening, the contact connection of the wires must be as strong, reliable and safe as possible. That is, the twisting must be performed with such high quality that the contact resistance is stable and does not change over time.

Preparing wires for twisting

Remember! Never do twisting under tension, even if you have a tool with insulated handles and dielectric gloves. To start, de-energize workplace by turning off the introductory machine for an apartment or house.

To get a good twist, you must follow these steps exactly:

1. Strip the wires to be connected from insulation, while preventing damage metal surfaces conductors.
2. Moisten a clean cloth with white spirit or acetone and wipe the exposed areas of the wires from dirt.
3. Now, using sandpaper, clean the veins to a metallic sheen.

stranded wires

Stranding stranded electrical wires can be done in different ways.

Parallel twist

The simplest method is parallel stranding, when both stripped wires are crisscrossed over each other at the stripping point and twisted at the same time. Such a connection gives reliable contact, but it will not tolerate the applied force to break and vibration.

This method is best used for copper wires, when one of them is solid and the other is stranded. A monolithic wire must be stripped of insulation a little more than a stranded one. After twisting, an additional bend is made from the remaining copper monolithic tail in the direction of twisting, due to this, the connection is more reliable. This method is also suitable for twisting aluminum conductors with different cross sections.

The advantage of parallel stranding is that it can be used to connect more than two wires at the same time.

Sequential stranding

In the serial method, each wire connected is wound onto another. The reliability and contact of such a connection will be optimal, but this twist can be used only for two wires, no more.

Fold the stripped strands crosswise on top of each other approximately in the middle of the bare area and start twisting. One wire goes around the other wire, just wrap the second wire around the first.

Bandage twist

Stranded wires can be connected to each other by the method of bandage twisting. In this case, the wires to be connected are stripped to the same length and applied parallel to each other. In this position, they are fixed with a third wire, which is tightly wound onto the bare surface of the connected cores.

Please note that using such a twist, you can connect hard stranded wires, but you must use a soft (flexible) wire as a fixing wire. The tighter you make the winding of the fixing wire, the more reliable the contact connection will be.

More than two conductors can be connected using a bandage twist.

Solid wires

All of the above methods of twisting stranded wires can also be used for single-core wires. But it is best to use a parallel connection in this case.

Remember the most important thing, before connecting single-core wires, the insulating layer on them should only be stripped along the conductor at an angle. This is especially true for aluminum conductors. If you run the knife at a 90 degree angle around the conductor, the insulation will of course come off. But in further work, with the slightest movement at the place of the incision, the conductor will break over time and, ultimately, the core will break.

Strip the insulating layer on the connected wires by 3-4 cm. Lay the wires on top of each other at an angle of 45 degrees, but not in the place of the bare wires, but 1.5-2 cm higher from the place where the insulation was cut. Hold this place firmly with your left hand, start twisting both wires with your right hand. First, they will twist together with the insulating layer, then the connection of purely bare cores will already go.

No matter how strong your hands are, at the end be sure to finish twisting with pliers, especially for aluminum wires again.

Another important tip! After you make a twist, do not rush to isolate it. Give electrical circuit work for several hours, then turn off the introductory machine to the apartment and check the temperature at the place of twisting. If the node is hot, then the contact connection turned out to be unreliable and it is better to redo it. If no heating is detected, then the twisting is done with high quality, it can be insulated.

If you need to perform a large number of twists, you can use a screwdriver with a homemade fixture, as shown in the video below:

Ways to isolate twists

Twisting the wires is half the battle, it is very important to insulate this place with high quality. There are three ways to insulate the made electrical assembly: using insulating tape, heat-shrinkable tubing and PPE caps. Let's consider each of them in more detail.

Insulating tape

Insulating tape is a special material, the main purpose of which is to isolate the junction of electrical cables and wires. No matter what modern technologies appear, you can hardly meet an electrician who does not have a roll of electrical tape in his pocket. This is the most common and inexpensive insulating material.

There are many varieties of it. Tapes are made on the basis of mica and fiberglass, polyester and epoxy films, acetate fabric and paper. To isolate the strand in the household electrical network, we recommend using PVC tape (it is based on polyvinyl chloride). For its manufacture, a polyvinyl chloride film is taken and glue is applied on top. The quality of the insulating tape itself depends on the quality of these two components, and, accordingly, the reliability of the insulated junction.

Electrical tape is considered the best, for the manufacture of which rubber-based glue is used and pvc film class A. This material has such positive qualities as:

1. High adhesion (adhesion of dissimilar surfaces).
2. Increased elasticity (excellent stretches and glues).

So be sure to consider this when buying electrical tape.

Insulating tape should be wound around the twisted section in at least two layers. Start winding 2-3 cm above the bare twist, the tape should be applied over the wire insulation. This will achieve maximum tightness and insulating reliability, protect the contact connection from moisture. Then wind a little at an angle, moving towards the end of the twist. Having reached the end, bend the tape around the tip of the twist and continue winding now in the opposite direction. Having reached the place where the winding began, cut the insulating tape with a knife. For efficiency, you can repeat the same thing again and make four layers of insulation.

thermotube

A heat-shrinkable tube (abbreviated as HERE) is made of thermopolymer materials that tend to change their geometric shape and dimensions (shrink or expand) under the influence of hot air, water or elevated temperature.

The main advantage of thermotubes is that they can be put on objects with a complex profile, which is exactly what the twisted wires have. Heat shrink tubing provides excellent electrical insulation and protects against mechanical damage. Tubes are available in different diameters. The material from which they are made does not support combustion and is not toxic.

For thermal effects on the tubes, industrial hair dryers are used. This tool is not cheap and buying it just to insulate the splicing of wires is not economically viable. Therefore, in domestic conditions, they often use an ordinary hair dryer or a lighter.

It is important to remember that with this method of insulation, the heat-shrinkable tube must be put on one wire to be connected in advance (before twisting).

Cut off the tube with a margin, when it is put on a bare area, it should protrude at least 1 cm onto the insulating layer of the conductor.

When the connection of the electrical wires with a twist is completed, pull the tube over this place. Direct the heat jet of a hair dryer or the flame of a lighter at it, under the influence of hot air, the tube will instantly decrease in size and tightly compress the insulated area. Reliable, fast and inexpensive way.

Keep in mind that the connected wires, which are insulated with a heat pipe, can be used for laying in the ground or when immersed in water. This insulating material is recommended for use outdoors, in baths and bathrooms, as it will reliably protect the place of twisting from moisture.

How to choose to use heat shrink tube shown in this video:

PPE caps

When installing wiring in an apartment or house, PPE caps (connecting insulating clamp) can be used as insulation for connection points.

In this case, it is enough to make only high-quality twisting, without soldering. The tip must be cut off and put on PPE with force, the compression springs inside the cap will move apart and tightly wrap around the unit to be connected. For a better fit on the connection surface, turn the cap clockwise.

Now you know how to twist the wires correctly, what material is better to choose for insulating the junction. It is clear from the article that it is not at all necessary to be a professional electrician to perform twisting, such work can be done by anyone who knows how to hold pliers in their hands. Just do not forget that twisting is only an important stage that must be completed by welding or soldering.

The safe operation of the electrical network depends on whether the wires are twisted correctly, whether the features of the connections between copper and aluminum cables are taken into account. It is necessary to take into account the cross section and the number of cores in the wires. Basic knowledge of the basic principles of cable splicing is the key to quality work on the installation of an electrical network.

It is important to know and apply, but why?

Electric current - source heightened danger. Neglect of the rules for installing the electrical network can lead to such consequences as:

• electric shock;
• poisoning with toxic smoke from burning insulation;
• fire.

Poor quality twisting is one of the reasons for such consequences. In places of poor connection, the passing current experiences increased resistance. The resulting thermal energy does not have time to dissipate, excessive heating occurs. With an increase in load in this section of the circuit, the resistance grows even more, and a short circuit occurs.

Twisted wire connections made in compliance with the rules guarantee the safe operation of the network. At the point of contact, the resistance will not increase, the current will pass through the conductor. United electric wires can be hidden in a box or under plaster. There will be no consequences if you follow the instructions for twisting.

Basic ways

Cores made of one metal, for example, copper wires, it is allowed to twist among themselves directly. The most common are the following:

• simple twist;
• bandage;
• chute twist.

The simple correct twisting of electrical wires is known to every electrician who once connected them together with his own hands. For two cores with a cross section of more than 4 square meters. mm. you need a bandage method, in which they tie it with a third wire. Twisting gutter - connection method aluminum wires when the ends are crocheted, hooked and wrapped.

When connecting copper and aluminum, which have different resistances, an additional conductor is required. It could be a brass tube connecting block or slip-on terminal. Threaded connections are also used with the obligatory use of additional washers with a cut. In such connections, it is necessary to increase the contact area, which is achieved by flattening the cores and reducing the resistance to the passing current.

Modern materials

Manufacturers of electrical installations offer their own solutions to the issue of connecting wires. Prefabricated compact connectors are a modern alternative to cable twists. For example, PPE clamps for twisting are a cone-shaped spring installed in a dielectric housing. Caps inserted into such PPE, bundles of wires are scrolled several turns and securely fixed.

For quick connection, Wago terminals of the same manufacturer are suitable. The joint in them occurs automatically: when the core is inserted into the corresponding hole, a flat-spring clamp is triggered. Such terminals are either disposable or reusable. Due to the ease of use, wiring is easy and the contact is reliable.

Do not forget the standard terminal blocks, which are universal for any type of connection. Made using a last, the connection is not inferior to either Wago or PPE caps.

One-piece crimping

For twisting stranded wires, special one-piece crimped connections are used. This connection method should be used for identical metals, because due to the difference in resistance in each crimping, contact, for example, copper with aluminum, will lead to heating. If the twist is made of copper wires, this should also be the connecting tube, the diameter of which approximately corresponds to the thickness of the wires being connected. Pre-twisting the wires is optional.

The cables inserted into the tube are crimped with press tongs on both sides. At least three layers of insulating material are applied to the resulting joint. As an alternative to electrical tape, ready-made crimps with an insulating cap can be used. Such a tube is crimped immediately with a polyethylene cap, which gently deforms and reliably insulates the joint.

Tip: before twisting the cores, it is necessary to calculate the load on electrical network. To do this, the power of all electrical installations that can work simultaneously is summed up. The minimum section of one of the cables to be connected must correspond to the calculated load.

What about a larger section?

Use of standard connection options for conductors with a cross section of 10 mm. sq. and is no longer allowed. In such cases, the ends of the cable are pressed with a special tip, on the sides of which there is a sleeve and a ring. One or more twisted wires are inserted into the sleeve and crimped with press tongs such as PK, PMK, PKG or PK. The ferrule ring is designed to be connected to a terminal or contact pad of another wire.

As a rule, connections through a lug with a ring are used to connect a contact wire in power shields. In such installations, it is not allowed to simply twist the cores together, because. high voltage instantly burn the wires at the joints.

Soldering iron to help

In addition to twisting, soldering is used at the joints. This method is used in places of high humidity, where the requirements for the resistance of wires to oxidation are most important. The pre-made twist is melted with rosin, after which solder is applied to it. At the same time, the power of an ordinary household soldering iron is enough, it is important to exclude the formation of sharp burrs on the solder. After drying, they are removed with a needle file, because. there is a risk of damage to the insulation.

The use of solder helps to connect twisted thin stranded wires. The contact surface after processing with a soldering iron increases, therefore, the contact area of ​​the joints becomes larger. It should be borne in mind that the load on the connected wires, regardless of the use of soldering, is calculated according to the cross section of the smallest of them.

original solutions

About how to do correct twist using non-standard solutions, it is not necessary for everyone to know, but in some cases it is precisely such knowledge that helps to cope with the work. For example, how to make a twist in which it is necessary to connect not two or three cores, but several dozen pairs? For this, a special mechanical device is used - manual press equipment. Both stranded and single-core wires of the same metal are twisted with such a press.

Sometimes, on the contrary, it is necessary to decide how to properly twist for low-current installations: power cords, LEDs, telephones, etc. For this, special connectors are used, which are plastic caps for twisting wires, inside of which there is a metal alloy plate in a special solution. It is a hydrophobic gel that prevents rust and protects the contact from oxidation and moisture ingress.

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