Connection of flexible wires. Methods for connecting electrical wires

How to connect the wires correctly? Every man has asked this question at least once in his life, even if he is not an electrician. IN Everyday life We often have to deal with similar questions. The electrical plug fell off, the chandelier wire broke, the socket stopped working, the connection to the home phone, there is no voltage in the vehicle’s on-board network, etc. All these problems are easy to solve if you have basic knowledge of electrical engineering and observe safety when carrying out installation or repair work.

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

Why you can’t directly connect wires of different metals

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

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

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

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

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

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

Twisting (twisting).
Bandaging.
Welding.
Soldering.
Crimping.
Riveting.
Terminal connection.
Connection using terminal strips and clamps (terminal blocks).
Threaded connection.
Connection by piercing conductors.
Cable compression.
Connection using a “nut”.

Twisting

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

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

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

Bandaging

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

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

Welding

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

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

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

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

Soldering

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

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

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

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

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

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

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

Crimping

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

To do this, it is enough to have:

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

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

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

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

Riveting

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

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

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

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

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

Terminal connection

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

Terminal strips and clamps

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

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

with bolt clamp;
self-clamping with spring clamp.

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

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

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

Threaded connection

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

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

Piercing

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

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

Cable compression

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

Connection "nutty"

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

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

In private construction, sooner or later the need to install electrical networks arises. Some people turn to specialists for help, others want to do it themselves. The process itself is not very difficult if you have certain skills and knowledge of safety standards, but this mainly concerns the connection of wires of the same cross-section.

But quite often situations arise when it is necessary to reliably connect three or more wires to each other, and they all have different cross-sections. In this regard, the question of how to correctly and safely connect wires of different sections is currently one of the most pressing when installing electrical networks.

Methods for connecting wires of different sections

Connecting copper wires of different thicknesses is not the most difficult process. However, for maximum reliability and safety, certain requirements must be observed here. There are several ways to connect three wires of different cross-sections:

welding or soldering;
using screw clamps;
using self-clamping terminals;
bolted connection;
branch compression;
using copper tips.

Three wires of different cross-sections can be reliably connected using any of the listed methods, but it is important to remember that when installing sockets and switches, cables of different thicknesses cannot be connected to one contact. In this case, the thinnest one will not be pressed tightly enough. And this, in turn, can negatively affect operational safety.

Connecting wires of different sections by welding or soldering

The simplest, but fairly reliable way to connect cables that have different thicknesses. In this case, three wires can be connected to each other by rigid twisting and subsequent fixation. But here it should be remembered that a reliable connection is only possible between wires of approximately the same cross-section. Twisting of wires whose diameters differ significantly cannot be reliable.

You need to carefully twist three wires of different sections together. Each copper wire should tightly wrap around the adjacent one. The gaps between them should be minimal. Otherwise, this will affect the safety of subsequent operation.

Before you begin directly twisting the three wires, lay them out in front of you and sort them by thickness. You cannot wind a thin wire onto a thick one - this will affect the quality of the contact. Such a connection will not last long.

Connecting three wires of different sections using screw terminals

Three wires of different thicknesses can be reliably connected to each other using special ZVI screw clamps. The clamps have a very convenient design and allow you to create contact between cables that have different cross-sections. The strength of the connection is achieved by using separate screws for each clamp.

You need to select ZVI clamps taking into account the cross-section of the wires that will be connected, as well as their current load. For reliable contact, it is recommended to connect three wires of adjacent sections. Let us conventionally designate the cross-section of the connected conductors as SPP, and the permissible long-term current as DDT. Below are the parameters of clamps and wires:

ZVI-3 - SPP 1 - 2.5; DDT - 3;
ZVI-5 - SPP 1.5 - 4; DDT - 5;
ZVI-10 - SPP 2.5 - 6; DDT - 10;
ZVI-15 - SPP 4 - 10; DDT - 15;
ZVI-20 - SPP 4 - 10; DDT - 20;
ZVI-30 - SPP 6 - 16; DDT - 30;
ZVI-60 - SPP 6 - 16; DDT - 60;
ZVI-80 - SPP 10 - 25; DDT - 80;
ZVI-100 - SPP 10 - 25; DDT - 100;
ZVI-150 - SPP 16 - 35; DDT - 150.

At making the right choice using a screw clamp, you can create a truly reliable connection that will ensure uninterrupted operation of the electrical network.

Connect wires of different sections using bolts

Another way to connect wires of different sections to each other is to create contact using bolts, washers and nuts. According to professional electricians, this connection is the most durable and strong. The process itself is not too complicated and takes minimal time. The procedure goes as follows:

the copper conductors of the wire are carefully stripped (the length of the stripped section of the conductor depends on the diameter of the bolt);
the stripped core is bent in the shape of a loop;
the loop is put on the bolt;
an intermediate washer is installed on top;
then a loop of wire of a different cross-section is put on and secured with an intermediate washer.

This continues until all the wires are connected to each other. After putting on the last loop and the last washer, the structure is firmly tightened with a nut.

Using copper lugs for contact connections

Also very in a simple way Creating a reliable connection is the use of copper tips. They are recommended to be used for contacting large diameter wires. Before starting the procedure, it is necessary to prepare not only the tips themselves, but also special equipment - crimping pliers or a hydraulic press.

Despite all the obvious advantages, this type of connection has one (but significant) drawback - it is quite large in size, due to which the resulting structure may not fit into every junction box. Nevertheless, experts actively use this method.

The process of creating a contact is as follows:

wires of different sections are carefully straightened;
the veins of each of them are stripped to about two to three centimeters;
a tip is put on each stripped core and clamped using a hydraulic press or crimping pliers;
Then the bolts are put on, and the wires are connected with a nut.

After all the work is done, you need to carefully isolate the connection point so that no dangerous situations arise during operation.

Do-it-yourself electrical wiring and creating contacts using terminals

Universal clamp terminals appeared on the market relatively recently, but almost immediately began to be in serious demand not only among specialists, but also among potential clients who prefer to carry out all electrical work at home themselves.

Using self-clamping terminals, you can create strong and reliable contacts between several wires ( three or more). The main advantage of such terminal blocks is their almost unlimited functionality - they can be used to connect wires whose sizes vary significantly.

The design of the terminals provides for the presence of holes into which pre-stripped conductors are inserted. For example, you can insert a wire with a cross-section of 1.5 mm into one hole, a wire with a diameter of 4 mm into another, a wire with a diameter of 4 mm into the third, and so on. And after connecting them, the contact will be quite strong and reliable.

There are several more ways how to connect three or more wires different diameters, but they are used quite rarely due to the complexity and duration of the process itself. If you want to use one of them, first consult with a specialist who is competent in this area.

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 look at 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 connect both monocores and stranded wires together.

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 enough old look connections, 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, they measure transition resistances on different types of connections.

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 are 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.

Crimping with sleeves 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.

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

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

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

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

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

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

Connecting wires in junction boxes

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

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

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

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

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

Wire crimping

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

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

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

Conductor crimping

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

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

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

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

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

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

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

Soldering wires

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

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

The soldering of conductors looks like this:

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

Welding

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

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

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

The wire welding process includes the following operations:

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

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

Connecting wires to electrical equipment terminals

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

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

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

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

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

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

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

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

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

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

Here are the factors that determine the choice of connector:

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

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

Existing methods

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

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

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

Installation of PPE caps

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

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

Advantages of using these products:

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

Flaws:

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

Crimping with special sleeves

Stranding and insulation

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

Advantages:

simplicity of electrical installation work;
no material costs.

Flaws:

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

WITH using existing methods We have figured out the connections of the wires in the box, now we will consider the remaining, important issues of this topic.

What to do if there are several wires?

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

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

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

What to do if the wires are of different sections?

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

Please note that if the wires are made of different material, then it is necessary to use special pads with paste inside, which will prevent oxidation of the wires. Such pads include products from Wago.

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

Combining stranded and single-core wires

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

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

How to carry out work in water and land

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

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

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

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