Correct twisting and types of connection of electrical wires. Correct twisting of electrical wires Methods of twisting wires

How to connect a single-core and stranded wire so that this does not lead to problems in the future, and the contact connection serves us for many years? And in general, how to make connections correctly various types wires?

We will try to answer all these questions in our article, and we will also analyze what such rules are associated with and what dangers are hidden behind an incorrect connection.

First of all, let's look at what the requirements for high-quality contact connections are related to. It is not without reason that clause 2.1.21 of the PUE separately stipulates methods for connecting wires, and allows only screw or bolt clamps, crimping, welding or soldering.

• This is primarily due to the fact that these types of connections can provide the required level of durability and reliability of the connection.
• After all, any electrician will tell you that more than 90% of all damage occurs at contact connections, and that is why so much attention is paid to them.

• After all, what is a poor-quality contact connection is a connection that has a high contact resistance.
• And since we have resistance, this means heating.
• As we remember from the physics course, any conductor in a heated state has greater resistance than a conductor with a lower temperature. Therefore, an avalanche-like process results. A poor-quality contact connection causes the conductor to heat up and its resistance increases even more. As a result, it heats up even more - until the point comes at which it simply melts. As a result, our main concern is to ensure minimum resistance between the two conductors being connected.

• This is achieved by ensuring the proper area of ​​contact between the two conductors, as well as by ensuring the maximum possible contact between them. That is, it will heat up and cool down. And as we know, heating leads to expansion of materials, and cooling, accordingly, to contraction. As a result, our contact connection, which is not fixed by any third element, can quickly become of insufficient quality.

Note! Surely each of you can give dozens and hundreds of examples where twisting has lasted for decades, and even now looks better than screw or bolt connections. But, as they say, exceptions to the rule only confirm the rule itself. According to statistics, twisted joints are damaged much more often than other types of joints.

Correct connection of conductors

Now we can talk about how to correctly connect a single-core and stranded wire, two single-core or two stranded wires. And also, which type of connection for each of these types will be optimal, and which should be used only with certain restrictions.

Connection using the compression method

By compression method, PUE means screw or bolt connection of conductors. The same type of connection includes the now popular Wago terminals, which use the compression method through the use of springs or special mechanisms.

• On this moment The compression method is one of the most popular joining methods. After all, the price of terminals based on this method is one of the lowest. The installation process is simple and does not require additional equipment, and the method itself is quite reliable.

• For wires of small cross-section, the screw connection method is predominantly used - or the compression method using a special mechanism. The essence of the screw method is that two conductors are installed in a brass tube, which are then each clamped with its own screw.
• This method is well suited for connecting two single-core copper conductors. If aluminum is used, then this material is softer, and when clamping it with a screw, you can either critically reduce its cross-section or completely crush it. Therefore, for aluminum wires, the use of this method is undesirable, or it should be used with extreme caution.

In the photo - a tip for a stranded wire

• Using a screw clamp to connect multi-core wires is also associated with the possibility of breaking individual wires that make up the conductor in whole or in part during the process of tightening the screw. To protect the wires from mechanical influences, special tips should be used.
• Using special lugs, stranded wires can be connected both to each other and between single-core wires using screw terminals.

• There are screw terminals with a special clamping pad, which provides clamping over the entire cross-section of the brass tube. In this case, the use of special lugs for stranded wires is not necessary.

• As for Wago terminals and the like. There is still debate among electricians about their reliability and durability. Some argue that the use of springs in terminals is not the best option, others that it is very convenient and the springs are quite reliable.

The electrical circuit is located over the area of ​​virtually the entire frame, providing the room with electricity for household and industrial devices, depending on the purpose of the building. Essentially, a cable is supplied from the central network, which is subsequently placed in the switchboard, from which several more come out, are routed to different ends of the room and connected to the distribution box, from where the final wires come out, ultimately connected to sockets, switches, etc. . Precisely in the distribution. boxes are created greatest number connections, and sometimes a soldering iron, welding, connectors are not used, but instead twisting wires, which does not require special devices or tools, but only those things that virtually everyone has (knife, pliers).
Content:

How to properly twist wires

In order to virtually reduce the possibility of occurrence and ignition, the twists in the distribution boxes must be made with high quality. If a person performs such an action for the first time, it is better to first carefully read the rules of such a connection, and only after that begin to perform the work. Let's figure out how to make twists correctly, what types there are, and what problems you may encounter when performing this work.

To begin with, it is worth saying that connecting two wires of different metals by twisting is not recommended. Many analytical articles and arguments have been written about this as to why this should not be done:

• different coefficients of thermal expansion (metals react differently to heating and cooling, as a result of which the contact gradually deteriorates);
• the appearance of an oxide film on the aluminum wire (it does not allow current to fully flow, the wire heats up and breaks down over time);
• structural destruction of aluminum during electrolysis (these two metals form a galvanic couple, and after exposure to a humid environment, the metal ends are subject to heating and subsequent destruction).

Twisting of copper and aluminum wires

Copper and aluminum cannot be connected directly to each other. However, in many houses there are aluminum wires that need to be connected to copper wires, and twisting is sometimes the only way to connect. In this case, it is important to adhere to certain rules that will allow such fastening to last as long as possible.

• To begin with, it is worth noting that the conductors must be tightly wrapped around each other. If their diameter is significant, there must be at least 3 turns, and if the diameter is up to 1 mm, in this case it will be necessary to wrap the wire around each other more than five times to ensure high-quality transmission of electrical flow. Also, after this it is very important to treat the bare surface with a special varnish that is resistant to water and moisture.
• When connecting copper and aluminum wires, it is better to use a special steel plate placed between them. This will avoid their direct contact. Thus, the service life of such a connection will be much longer. If you don’t have such a component at hand, then you can resort to treating the bare copper wiring with solder, which will also avoid mechanical contacts of these two metals.
• The ideal solution for connecting copper and aluminum conductors is to first apply solder to the copper core. Especially such pre-treatment is often used when connecting single- and multi-core wires, when in this way a wire consisting of several conductors is converted into a single-core one.

Twisting wires of different sections

This type of work implies the unambiguous use of additional means for connection. Such devices can be screw clamps, self-clamping terminals, bolts, tinned copper lugs, and walnut-type holes. Also, in order not to purchase additional components, you can use soldering or welding, etc.

If the difference in the diameter of the wires is insignificant, for example, 4 and 2.5 mm, then connecting them by twisting is not so difficult. To do this, you need to carefully wrap them around each other, after which you need to use welding or soldering. This fastening of two conductors will last for many years without complaints.

In other cases, twisting wires will not be reliable and durable. In such situations, you simply cannot do without additional components. IN different situations use certain devices:

• if significant, it is best to use a self-clamping terminal;
• for branching from the main line to the distribution. The shield uses a branch compressor, which among experts is also called “Nut”;
• To connect wires with a large diameter, a copper-tind tip is used.

Errors when twisting wires

The most common problem with connecting conductors in this way is that one wire wraps around another. This is completely wrong. The wires should evenly wrap around each other, thereby ensuring reliable passage electric current and create mechanical strength so that such fastening will last for many years.

The length of the twist depends directly on the diameter of the conductors themselves. It is worth considering that the minimum threshold for this characteristic should be no less than 3 cm. Otherwise, everything depends on the diameter of the wires: the larger the diameter, the greater the length of the created twist should be, but there are no specifically prescribed standards in this regard, Each specialist decides for himself what this value should be in order for the connection to be reliable and of high quality.

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 when rough editing. This is explained by the need to establish the correct operation of 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 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 using the correct execution methods. Such measures prolong the trouble-free operation of the soldering point and the entire circuit.

Resistance at the junction of the wires

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 impact. One or two attempts at gossip - and he breaks off.

Cable cores can be single-wire 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.

In the absence of special devices for splicing 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.

The easiest 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.

Accession additional wire and branches for each option occur 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. This is clearly noticeable in production areas, where installation is carried out using progressive methods, and outdated joints are replaced.

First of all, you must understand that different conditions may be applied Various types connections. And their choice depends on the specific task at hand.

For example, it is much more convenient to connect small-section wires up to 2.5 mm2 in a compact junction box with terminal blocks or clamps. But if we are talking about a groove or a cable channel, then the sleeves come first.

Let's consider the three most simple and at the same time reliable types of connections.

Let's start with the connection type PPE. It stands for:

• WITH unifying

• AND insulating

• Z pressure

It looks like a simple cap. Comes in different colors.

Moreover, each color means that it belongs to specific sections of the cores.

The cores are inserted into this cap and twisted together.

How to do it correctly, first twist the wires and then put on the cap or twist them directly with the PPE itself, is discussed in detail in the article “.”

As a result, thanks to PPE, you get a good old twist, only immediately protected and insulated.

On top of that, it has a spring-loaded contact that prevents it from coming loose.

In addition, this process can be slightly automated by using an attachment for PPE for a screwdriver. This is also discussed in the above article.

The next type is Wago terminal blocks. They also come different sizes, and for different numbers of connected wires - two, three, five, eight.

They can be used to connect both single-core and stranded wires.

Moreover, this can be implemented as in different types Vago, and in one single thing.

For stranded ones, the clamp must have a latch-flag, which, when open, easily allows you to insert the wire and clamp it inside after latching.

According to the manufacturer, these terminal blocks in home wiring can easily withstand loads of up to 24A (lights, sockets).

There are some compact specimens also available for 32A-41A.

Here are the most popular types of Wago clamps, their markings, characteristics and what cross-section they are designed for:

Series 2273 Series 221-222 Series 243 Series 773 Series 224

There is also an industrial series for cable cross-sections up to 95mm2. Their terminals are really large, but the principle of operation is almost the same as that of small ones.

When you measure the load on such terminals, with a current value of more than 200A, and at the same time you see that nothing is burning or heating, many doubts about Wago products disappear.

If you have original Vago clamps, and not a Chinese counterfeit, and the line is protected by a circuit breaker with a correctly selected setting, then this type of connection can rightfully be called the simplest, most modern and convenient to install.

Violate any of the above conditions and the result will be quite natural.

Therefore, there is no need to install wago at 24A and at the same time protect such wiring with a 25A automatic. In this case, the contact will burn out if overloaded.

Always choose the right terminal blocks for your car.

As a rule, you already have automatic machines, and they primarily protect the electrical wiring, and not the load and the end consumer.

There is also a fairly old type of connection, such as terminal blocks. ZVI – insulated screw clamp.

In appearance, this is a very simple screw connection of wires to each other. Again, it comes in different sections and different shapes.

Here they are specifications(current, cross-section, dimensions, screw torque):

However, ZVI has a number of significant disadvantages, due to which it cannot be called the most successful and reliable connection.

Basically, you can only connect two wires to each other in this way. Unless, of course, you specifically choose large pads and shove several wires there. What to do is not recommended.

This screw connection works well for monocores, but not for stranded flexible wires.

For flexible wires, you will have to press them with NShVI lugs and incur additional costs.

You can find videos online where, as an experiment, transition resistances on different types of connections are measured with a microohmmeter.

Surprisingly, the lowest value is obtained for screw terminals.

But we should not forget that this experiment refers to “fresh contacts”. Try making the same measurements after a year or two of intensive use. The results will be completely different.

Copper and aluminum connection

Often a situation arises when it is necessary to connect a copper conductor to an aluminum one. Because Chemical properties Copper and aluminum are different, then direct contact between them, with access to oxygen, leads to oxidation. Often even copper contacts on circuit breakers susceptible to this phenomenon.

An oxide film forms, resistance increases, and heating occurs. Here we recommend using 3 options to avoid this:

They remove direct contact between aluminum and copper. The connection occurs through steel.

The contacts are separated from each other in separate cells, plus the paste prevents the access of air and prevents the oxidation process from developing.

The third simple way to connect conductors is crimping with sleeves.

GML sleeves are most often used for joining copper wires. Deciphered as:

• G Ilsa

• M single

• L narrowed

For connecting pure aluminum - GA (aluminum sleeve):

To switch from copper to aluminum, special adapters GAM:

What is the crimping method? Everything is quite simple. Take two conductors and strip them to the required distance.

After this, on each side of the sleeve, the conductors are inserted inside, and the whole thing is crimped with press pliers.

Despite its obvious simplicity, there are several rules and nuances in this procedure, if not followed, you can easily ruin a seemingly reliable contact. Read about these mistakes and rules on how to avoid them in the articles “” and “”.

To work with conductors of large sections 35mm2-240mm2, a hydraulic press is used.

Up to cross-sections of 35mm2, you can also use a mechanical one with a large span of handles.

The sleeve must be crimped two to four times, depending on the cross-section of the wire and the length of the tube.

The most important thing in this work is to choose the correct sleeve size.

For example, when connecting a monocore, the sleeve is usually taken to a smaller cross-sectional size.

And in this way you can connect several conductors at one point at the same time. In this case, only one sleeve will be used.

The main thing is to completely fill its internal space. If you are crimping three conductors at the same time, and you still have voids inside, then you need to “fill” this free space with additional pieces of the same wire, or with conductors of a smaller cross-section.

Sleeve crimping is one of the most versatile and reliable connections, especially when it is necessary to extend the cable, including the input cable.

In this case, the insulation turns out to be almost equivalent to the main one, when also using the outer tube HERE as a casing.

Of course, you won’t use either PPE or Wago for these purposes, but GML cartridges are just the thing! At the same time, everything comes out compact and can be easily reduced, either in a groove or in a cable channel.

Welding and soldering

In addition to all the above connection methods, there are two more types that experienced electricians rightfully consider the most reliable.

And even with its help it is not always possible to connect an aluminum monocore wire with a flexible copper stranded one. In addition, you are forever tied to an outlet or extension cord.

What if there is no voltage or generator nearby?

At the same time, on the contrary, 90% of electrical installers have elementary press pliers. It is not necessary to purchase the most expensive and sophisticated ones for this.

For example, batteries. It’s convenient, of course, just walk and press a button.

The Chinese counterparts also cope well with their task of crimping. Moreover, the entire process takes no more than 1 minute.

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 according to the PUE, twisting of wires is prohibited.

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 are still on the territory of the former large Soviet country made on twists.

I won't say that it's very good twist of wires- this is the most reliable and high-quality way to connect wires, although they are constantly trying to prove this to me. It seems that someone even took a measurement 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 realm of mythology among electricians. We will simply proceed from the point that good twisting can be called one of the stages and very important element methods of connecting wires, such as soldering or welding.

Before discussing further about correct twisting, let's dwell on what will happen if the wires are connected just like that, without technology, “as it happens.” In this case, it occurs at the point of contact of the two wires. There are two reasons for this - reduction in area cross section wires 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 metal atoms that make up the core with oxygen in the air. This 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” because they don’t react with anyone). In silver, the resistivity of the oxide film is the same as that of the metal itself, therefore silver is actively used in contacts of various electrical devices.

When the wire is heated by a current passing through it, the transition contact resistance increases even more, because The heat generated is not completely dissipated into 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 twisting area heats up more and more. Here you have one of the causes of fires due to so-called “faults in electrical wiring.”

I came across one case where an aluminum strand at a neighbor’s dacha lasted 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 itself. It was already written on the site.

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

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

So, what do you need to make a good wire twist?

First, you need to remove the insulation without damaging the wire cores. We clean the exposed area of ​​the core from dirt with a clean rag soaked in acetone or white spirit. Then we clean the wires with a wire brush or sandpaper to a metallic shine.

Next, we twist the stripped wires 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 core diameters from the insulation cut, and bring them behind each other. Using pliers we wind 5-7 turns of one core onto another.

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

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 bend the end of the branch strand tightly. After all these operations, the twisting will be mechanically strong and reliable.

There are many other ways to connect wires by twisting. All these methods are even given characteristic names.

For example, here are the methods shown in one famous book for young electricians:

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

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 once proven that).

Good twisting is also needed, for example, for a more modern and less time-consuming method of connecting wires - when using, which is a good alternative to electrical tape.

By appearance it is similar to a regular cambric, which is put on the twist 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 reliably insulates it.

Do the twists right!

If you have your favorite options for connecting wires, share and tell us about it in the comments to the article!