Methods of connecting wires: from twisting to soldering. Ways to reliably connect wires Correctly connecting wires

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

Wall Mounted Junction Box

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

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

The good old way of joining - twisting

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

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

twisting with soldering and twisting by welding

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

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

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

Terminal blocks

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

Branch cable clamps

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

Walnut clamp without cover

"Nut" fully assembled

Connection bars

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

Grounding bus

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

Spring terminals

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

WAGO 222 series

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

Wire installation in WAGO 222 series

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

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

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

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

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

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

Connecting different materials with a bolt

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

The final view of connecting wires made of different metals

Sleeve connections

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

Crimping the sleeve with a special press

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

In this article I will tell you about a real case of connecting wires in an apartment. I already have a lot of such articles, I will provide some links along the way. As usual, there will be a lot of photos, tips and instructions)

So, the story began with the fact that a client called me to his place, who was flooded by his upstairs neighbors. The house is an old two-story barracks, pre-war, the wiring is terrible. Namely - aluminum and copper in different combinations. The house and apartment were completed and rebuilt many times, and the wiring was redone accordingly.

Therefore, when water got on the electrical wiring, it led to the apartment being completely de-energized. The situation was aggravated by the fact that the apartment had just been renovated with good finishing, the walls were covered with expensive wallpaper and decorative stone. And, as always, before making repairs, the owners did not think about the fact that the wiring left much to be desired. That is, it is in unsatisfactory condition.

For a Russian person, as usual, until the thunder strikes... But for now it works - and okay!

So, I came that evening and restored the apartment from an electrical point of view, connecting the wires in the junction box with what I had in my arsenal - Wago of different models, PPE connectors.

But I immediately said that I don’t give any guarantee - perhaps in a day everything will burn again! And all the wire connections will need to be done in a normal way.

And now, half a year later - a call! It's time! It literally burned, the photo is at the beginning of the article, and here:

Consequences of connecting wires in a box through Wago terminals. At the top there is a hole in the suspended ceiling.

The fact is that the machines in the entire apartment were set at 25A. More precisely, there was actually 1 machine, since one was on phase, the second was on zero. This is the shield that was installed throughout the entire apartment:

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Let me remind you that you cannot do this, this bad tradition dates back to the times when round fuse plugs were installed after the meter. Why is this dangerous - if you hit zero (and here the chances are 50/50), and it seems like there is no “light” in the house, but all the electrical wiring is at phase voltage potential. Even the zero part, which was not dangerous before. Therefore, in this case there should be a two-pole machine, but not two single-pole ones.

It is clear that the connection of wires in the box with such protection burned out. Moreover, the wires that were connected through the terminals were old, oxidized, and of different sections.

Not only the input wire box (above the meter) burned out, but also the distribution box in the hallway, through which power was supplied to the kitchen and bathroom. Here's what happened to her:

As you can see, a whole collection of different terminal blocks was used to connect the wires.

This photo can be characterized by the words from the song - “I made him from what was...”

At the same time, Vago terminal blocks took on bizarre forms of techno-art:

Replacing connections

So, we have two junction boxes, the wire connections in which are completely useless. What should be done in such cases? Here are the main points:

Cut out the old terminal blocks with pliers,
Strip the wires to a good metal that has not darkened due to temperature. If necessary, cut the wire even shorter,
If necessary, extend the wires so that they can be connected,
During all these manipulations, understand the train of thought of the electrician who acted here 20-40-60 years ago. In other words, understand the wiring diagram,
Install a new junction box,
Connect the wires to each other using terminal blocks.

Here's how I did the electrical wiring repair in this case.

What's new in the VK group? SamElectric.ru ?

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After the meter, there were initially two 25-amp circuit breakers; from their output terminals I powered the following electrical panel:

I don’t remember the exact connection diagram now, but that’s not important right now.

I installed the following boxes:

Why two boxes instead of one? You will need to fit everything - all the wires and terminals. In addition, cutting off the burnt ends of the wires makes them shorter.

From this place, wires spread throughout the entire apartment (both copper and aluminum), and two VVG 3x2.5 cables arrive:

In this case, I use the TB2504 terminal block to connect the outlet circuits.

I’ll talk about such terminals later in this article.

For connecting lighting circuits - Vago terminals. Here's a closer look:

I am quite calm about such connections, and I can give a multi-year guarantee for such electrical wiring repairs.

Connecting wires with terminal blocks

Why do I like making connections with terminal blocks? The fact is that I can be quite confident in such connections, unlike Vago terminals (see photo of what happens in this article)

Such terminals have very low contact resistance and very high reliability if used correctly. The situation is almost the same with crimp connection sleeves. But for the sleeves you need a special tool - press pliers, and for the terminal block a screwdriver is often enough.

For better installation, you need to try to ensure that the area of contact of the wire with the terminal pad is maximum, and the wire itself is as clean as possible. Ideally, a flexible stranded wire should be terminated with lugs.

I already wrote about lugs for stranded wires in an article about the practical use of Vago terminals, the link was above. In addition, multi-core wires are discussed in the article.

There are many names for such terminals, and sometimes confusion arises.

Possible names are: a line of screw terminals, a terminal block, a terminal block, a terminal block, and, ultimately, a black carbolite terminal block.

In English, this name sounds like Screw Barrier Terminal Block. Abbreviated as Terminal Block, the first letters of these words (TB) are included in the trade name. Next come two numbers indicating the rated current, and two more numbers indicating the number of terminals in the block.

For example:

TB1512 (15Amp 12 terminals),
TB3504 (35A, 4 terminals),
TB45, TB60 – terminal blocks for 45 and 60 Amperes.

Here's an example of how I used these terminal blocks to power an entire office:

Read more about such important connections in the article.

These are the terminals I use where there are high currents and a high cost of error. For example, in hard-to-reach places, at the entrance to homes, etc.

I see only one disadvantage of such terminals - size. Such terminal blocks do not fit into standard distribution boxes and must be placed differently. For example, as shown in this article.

There is another connection option - through the terminals of circuit breakers, where the reliability is no less, and this method is used everywhere.

Walnut type compression

And for large currents and cross sections (more than 63A and more than 10 mm2 for copper) - a completely different story and philosophy.

It often happens here that you need to connect wires of different sections and materials (copper + aluminum). And the best thing that was invented for this is Nuts. Like in this photo:

Nuts for connecting wires

Here is another example of connecting wires with nuts:

Walnut connection in the floor panel

Most often they are installed in panels for entry into private houses and apartment buildings.

Video on connecting wires

Summary of the article - connect the wires so as to be 100% sure! I wish everyone a good contact!

When connecting wires of different diameters in series, the maximum load current will be determined by the cross-section of the wire with a smaller diameter. For example, a connection was made between copper wires with a diameter of 1.6 mm and 2 mm. In this case, the maximum load current on the electrical wiring, which is determined from the table, will be 10 A, and not 16 A, as for a wire with a diameter of 2 mm.

Connecting electrical wires by twisting

Until recently, twisting was the most common method of connecting wires when doing electrical wiring; due to its accessibility, all it took was a knife and pliers. But, according to statistics, twisting is an unreliable way to connect conductors.

According to the electrical installation rules (PUE), twisted connections when installing electrical wiring are prohibited. But, despite the noted disadvantages, the twisting method is currently widely used. Connecting conductors of low-current circuits by twisting, subject to certain rules, is quite justified.

The photo on the left shows how twisting is unacceptable. If one conductor is twisted around another, the mechanical strength of such a connection will be insufficient. When twisting wires, you must make at least three turns of wires around each other. In the middle photo, the twisting is done correctly, but a copper conductor is twisted with an aluminum one, which is not permissible, since when copper comes into contact with aluminum, an emf of more than 0.6 mV occurs.

In the photo on the right, the twisting of copper and aluminum wires is done correctly, since the copper wire is tinned with solder before twisting. You can twist several wires together at once; in a junction box, sometimes up to 6 conductors are twisted, wires of different diameters and from different metals, a stranded wire with a single-core wire. Only the stranded wire needs to be made single-core by first soldering it with solder.

Connecting electrical wires by soldering

The connection of copper wires with high-quality soldering is the most reliable and is practically not inferior to a solid wire. All of the above examples of twisted wires, except for aluminum and tinsel, when tinning the conductors before twisting and then soldering them with solder, will be reliable on a par with solid wires. The only drawback is the extra labor involved, but it's worth it.

If you need to connect a pair of wires and the twisted conductors must be directed in different directions, then a slightly different type of twist is used.

By splicing two pairs of double wires in the manner described below, it is possible to obtain a compact and beautiful connection by twisting both single-core and multi-core pairs of conductors. This twisting method can be successfully used, for example, when splicing broken wires in a wall, extending a wire when moving a socket or switch from one place on the wall to another, when repairing or extending the length of a carrying cable.

To obtain a reliable and beautiful connection, it is necessary to adjust the lengths of the ends of the conductors with a shift of 2-3 cm.

Twist the conductors in pairs. With this type of twisting, two turns are enough for a single-core wire, and five for a multi-core wire.

If you plan to hide the twists under plaster or in another inaccessible place, then the twists must be soldered. After soldering, you need to go over the solder with sandpaper to remove any sharp solder icicles that could pierce the insulation and stick out from it. You can do without soldering if the connection is accessible and the currents flowing through the conductors are not large, but the durability of the connection without soldering will be much lower.

Due to the shift of the twisting points, there is no need to insulate each of the connections separately. We attach a strip of insulating tape on both sides along the conductors. Finally, you need to wind three more layers of insulating tape. According to the requirements of the Electrical Safety Rules, there must be at least three layers.

Wires spliced and soldered in the manner described above can be safely laid in the wall and plastered on top. Before installation, it is advisable to protect the connection with a vinyl chloride tube placed in advance on one of the pairs of wires. I have done this many times, and the reliability has been confirmed by time.

Connecting wires in junction boxes

When I moved into an apartment built in 1958 and began doing renovations, I was immediately confronted with the blinking of the lighting bulbs in rhythm with the hammer blows on the walls. The primary task of repair arose, carrying out an audit of distribution boxes. Opening them revealed the presence of poor contact in the twisted copper wires. To restore contact, it was necessary to disconnect the twists, clean the ends of the wires with sandpaper and twist them again.

When trying to disconnect, I encountered a seemingly insurmountable obstacle. The ends of the wires broke off even without any effort. Over time, copper lost its elasticity and became brittle. When stripping the wire, the insulation was apparently cut in a circle with a knife blade and notches were made. It was in these places that the wire broke off. The copper became hardened due to temperature fluctuations.

You can restore the elasticity of copper, unlike ferrous metals, by heating it to red and quickly cooling it. But for this case, such a technique is unacceptable. The ends of the wires no longer than 4 cm remained. There was no choice for connection. Just solder.

I exposed the wires with a soldering iron, melted the insulation, tinned them with solder, tied them in groups with tinned copper wire and filled them with solder using a 60-watt soldering iron. The question immediately arises: how to solder the wires in the junction box if the electrical wiring is de-energized? The answer is simple, using a soldering iron powered by a battery.

So I updated the connections in all junction boxes, spending no more than 1 hour on each. I am completely confident in the reliability of the connections made, and this has been confirmed by the 18 years that have passed since then. Here's a photo of one of my boxes.

When leveling the walls with Rotband in the hallway and installing a stretch ceiling, the distribution boxes became a hindrance. I had to open them all, and the reliability of the solder connection was confirmed; they were in perfect condition. That's why I boldly hid all the boxes in the wall.

Connections currently practiced using a Wago flat-spring terminal block greatly reduce the time spent on installation work, but are much inferior in reliability to soldered connections. And if there are no spring-loaded contacts in the block, they make connections in high-current circuits completely unreliable.

Mechanical connection of wires

Soldering is the most reliable type of connecting wires and contacts. But it has disadvantages - the inseparability of the resulting connections and the high complexity of the work. Therefore, the most common type of connection of wires to electrical contacts of devices is threaded, screws or nuts. To ensure the reliability of this type of connection, it is necessary to perform it correctly.

Linear expansion due to temperature changes is different for metals. Aluminum changes its linear dimensions especially strongly, then, in descending order, brass, copper, and iron. Therefore, over time, a gap forms between the contact of the connected metals, increasing the contact resistance. As a result, the screws must be tightened periodically to ensure reliable connections.

In order to forget about maintenance, additional slotted washers, called split washers or Grover washers, are installed under the screws. The Grover selects the gaps that arise and thereby ensures high contact reliability.

Often electricians are lazy and do not twist the end of the wire into a ring. In this option, the contact area of the wire with the contact pad of the electrical device will be many times smaller, which reduces the reliability of the contact.

If the formed ring of wire is slightly flattened with a hammer on an anvil, the contact area will increase several times. This is especially true when forming a ring of stranded wire soldered with solder. Instead of a hammer, you can add flatness with a file, grinding off the ring a little at the points of contact with the contacts.

This is how it should be done ideal threaded connection of wires to contact pads of electrical appliances.

Sometimes it is necessary to connect copper and aluminum conductors with each other, or with a diameter of more than 3 mm. In this case, the most accessible is a threaded connection.

The insulation is removed from the wires to a length equal to four screw diameters. If the veins are covered with oxide, then it is removed with sandpaper and rings are formed. A spring washer, a simple washer, a ring of one conductor, a simple washer, a ring of another conductor, a washer and, finally, a nut are put on the screw, screwing the screw into which the entire package is tightened until the spring washer is straightened.

For conductors with a core diameter of up to 2 mm, an M4 screw is sufficient. The connection is ready. If the conductors are made of the same metal or when connecting an aluminum wire to a copper wire whose end is tinned, then there is no need to place a washer between the rings of the conductors. If the copper wire is stranded, then it must first be tinned with solder.

Connecting wires with a terminal block

Connecting wires with low current load can be done using terminal blocks. Structurally, all terminal blocks are designed identically. Thick-walled brass tubes with two threaded holes on the sides of each are inserted into the housing combs made of plastic or carbolite. The wires to be connected are inserted into the opposite ends of the tube and secured.

The tubes come in different diameters and are selected depending on the diameters of the conductors being connected. You can insert as many wires into one tube as its internal diameter allows.

Although the reliability of connecting wires in terminal blocks is lower than when connecting by soldering, much less time is spent on electrical installation. An undeniable advantage of terminal blocks is the ability to connect copper and aluminum wires in electrical wiring, since brass tubes are coated with chromium or nickel.

When choosing a terminal block, you need to take into account the current that will flow through the switched electrical wiring wires and the required number of terminals in the comb. Long combs can be cut into several short ones.

Connecting wires using a terminal block
with Wago flat spring clamp

Terminal blocks with flat spring clamps Wago (Wago) from a German manufacturer are widely used. Wago terminal blocks come in two designs. Disposable, when the wire is inserted without the possibility of removal, and with a lever that makes it easy to both insert and remove wires.

The photo shows a Wago disposable terminal block. It is designed for connecting any types of single-core wires, including copper and aluminum with a cross-section from 1.5 to 2.5 mm 2. According to the manufacturer, the block is designed to connect electrical wiring in junction and distribution boxes with a current of up to 24 A, but I doubt it. I think it’s not worth loading the Wago terminals with a current of more than 10 A.

Wago spring terminal blocks are very convenient for connecting chandeliers and connecting wires in junction boxes. It is enough just to forcefully insert the wire into the hole of the block, and it will be securely fixed. In order to remove the wire from the block, considerable force will be required. After removing the wires, deformation of the spring contact may occur and a reliable connection of the wires when reconnected is not guaranteed. This is a big disadvantage of a disposable terminal block.

A more convenient Wago terminal block is reusable and has an orange lever. Such terminal blocks allow you to connect and, if necessary, disconnect any electrical wires, single-core, multi-core, aluminum in any combination with a cross-section from 0.08 to 4.0 mm 2. Rated for current up to 34 A.

It is enough to remove 10 mm of insulation from the wire, lift the orange lever up, insert the wire into the terminal and return the lever to its original position. The wire will be securely fixed in the terminal block.

The Wago terminal block is a modern tool-free way to connect wires quickly and reliably, but is more expensive than traditional connection methods.

Permanent connection of wires

In some cases, when it is not intended to connect the wires in the future, they can be connected in a permanent way. This type of connection is highly reliable and is advisable in hard-to-reach places, for example, connecting the ends of a nichrome spiral with copper current-carrying conductors in a soldering iron.

Connecting thin wires by crimping

A simple and reliable way to connect wire cores is crimping. Wire strands are inserted into a piece of copper or aluminum tube, depending on the metal of the wires being connected, and the tube is pressed in the middle with a tool called a press pliers.

Crimping can be used to connect both single-core and stranded wires in any combination. The diameter of the tube must be selected depending on the total cross-section of the conductors. It is desirable that the conductors fit tightly. Then the connection reliability will be high. If in a stranded wire the conductors are twisted together, then it is necessary to develop and straighten them. There is no need to twist the wire strands together. The prepared conductors are inserted into the tube and crimped with press pliers. The connection is ready. All that remains is to insulate the connection.

Crimping tips are available for sale, already equipped with an insulating cap. Crimping is performed by compressing the tube together with the cap. The connection is immediately isolated. Since the cap is made of polyethylene, during crimping it is deformed and held securely, ensuring reliable insulation of the connection.

The disadvantage of joining by crimping is the need for special press jaws. You can make your own pliers using pliers with side cutters. You need to round the side cutter blades and make a groove in the middle. After such modification of the pliers, the edges of the side cutters will become blunt and will no longer be able to bite, but only squeeze.

Connecting wires of larger cross-sections by crimping

To connect electrical wires with a larger cross-section, for example, in power panels of houses, special lugs are used, which are crimped using universal press pliers, for example, the PC, PKG, PMK and PKG types.

To crimp each standard size of tip or sleeve, it requires its own matrix and punch, a set of which is usually included in the set of pliers.

To crimp a tip onto a wire, the insulation is first removed from the wire, the wire is tucked into the hole in the tip and inserted between the matrix and the punch. The long handles of the press pliers are used to squeeze. The tip is deformed, crimping the wire.

In order to correctly select the matrix and punch for the wire, they are usually marked and branded press pliers on the matrix have an engraving for crimping what section of wire the matrix is intended for. The number 95 embossed on the tip means that this matrix is designed for crimping into the tip of a wire with a cross-section of 95 mm 2.

Connecting wires with a rivet

It is made using screw connection technology, only a rivet is used instead of a screw. Disadvantages include the impossibility of disassembly and the need for special tools.

The photo shows an example for connecting copper and aluminum conductors. More details about connecting copper and aluminum conductors are described in the website article “Connection of aluminum wires”. In order to connect the conductors with a rivet, you need to first put an aluminum conductor on the rivet, then a spring washer, then a copper one and a flat washer. Insert a steel rod into the rivet gun and squeeze its handles until it clicks (this cuts off the excess steel rod).

When connecting conductors made of the same metal, there is no need to place a split washer (grower) between them, but put the groover on the rivet first or second to last; the last one must be an ordinary washer.

Connecting broken wires in the wall

Repairs should begin with very careful removal of the plaster in the area of damaged wires. This work is done with a chisel and hammer. As a chisel when laying electrical wiring in the wall, I usually use the rod from a broken screwdriver with a sharpened end of the blade.

Connecting copper wires broken in the wall

Take a piece of copper wire with a cross-section no less than the cross-section of the broken wire. This piece of wire is also covered with a layer of solder. The length of this insert must ensure an overlap of at least 10 mm over the connected ends of the wires.

The insert is soldered to the connecting ends. Solder should not be skimped. Next, the insulating tube is moved so as to completely cover the joint. If a sealed, moisture-resistant connection is required, then before putting on the tube, the soldered joint must be coated with silicone.

Connecting aluminum wires broken in the wall

A prerequisite for obtaining a reliable mechanical connection of aluminum wires is the use of a Grover-type washer. The connection is assembled as follows. A groover is put on the M4 screw, then an ordinary flat washer, rings of connected wires, then a simple washer and a nut.

Step-by-step instructions for connecting broken wires in a wall are outlined in the article “Connecting broken wires in a wall”

Connecting wires with slip-on terminals

Widely used in household appliances and cars is the detachable connection of conductors using slip-on terminals, which are placed on contacts 0.8 mm thick and 6.5 mm wide. Reliability of fixation of the terminal is ensured by the presence of a hole in the center of the contact and a protrusion in the terminal.

Sometimes the conductors break off, and more often the terminal itself burns due to poor contact and then it becomes necessary to replace it. Typically, the terminals are pressed onto the ends of the conductors using special pliers. Crimping can also be done with pliers, but you don’t always have a new replacement terminal on hand. You can successfully use a used one by installing the terminal using the following technology.

First you need to prepare the old terminal for reinstallation. To do this, holding the terminal with pliers at the press-in point, you need to use an awl or a screwdriver with a thin tip to move the tendrils that compress the insulation apart. Next, the wire is bent many times until it breaks off at the point where it exits the press fit. To speed things up, you can trim this area with a knife.

When the wire is separated from the terminal, a needle file prepares a place for soldering it. You can completely grind it off until the remaining wire is free, but this is not necessary. It turns out to be a flat platform.

The resulting area is broken through with solder. The conductor is also stripped and tinned with solder using a soldering iron.

All that remains is to attach the conductor to the prepared terminal area and heat it with a soldering iron. The antennae that fix the wire are bent after soldering the wire to the terminal, since if they are crimped before soldering, the antennae will melt the insulation.

All that remains is to pull on the insulating cap, put the terminal on the desired contact and check the reliability of the fixation by tugging on the wire. If the terminal has come off, then it is necessary to tighten its contacts. A home-made terminal attached to a wire by soldering is much more reliable than one obtained by crimping. Sometimes the cap is put on so tightly that it cannot be removed. Then it needs to be cut and after installing the terminal, cover it with insulating tape. You can also stretch a piece of vinyl chloride or heat-shrinkable tube.

By the way, if you hold a vinyl chloride tube in acetone for about five minutes, it increases in size by one and a half times and becomes plastic, like rubber. After the acetone evaporates from its pores, the tube returns to its original size. About 30 years ago, I insulated the bases of light bulbs in a Christmas tree garland in this way. The insulation is still in excellent condition. I still hang this garland of 120 6.3 V light bulbs on the Christmas tree every year.

Splicing stranded wires without twisting

Stranded wires can be spliced in the same way as single-core wires. But there is a more advanced method, in which the connection is more accurate. First you need to adjust the lengths of the wires with a shift of a couple of centimeters and strip the ends to a length of 5-8 mm.

Fluff the slightly cleaned areas of the pair to be joined and insert the resulting “panicles” into each other. In order for the conductors to take a neat shape, they need to be tied together with a thin wire before soldering. Then lubricate with soldering varnish and solder with solder.

All conductors are soldered. We clean the soldering areas with sandpaper and insulate them. We attach one strip of electrical tape on both sides along the conductors and wind a couple more layers.

This is what the connection looks like after covering it with insulating tape. You can further improve the appearance if you use a file to sharpen the solder joints on the insulation side of adjacent conductors.

The strength of connected stranded wires without twisting by soldering is very high, as the video clearly demonstrates. As you can see, the connection can withstand the weight of the monitor 15 kg without deformation.

Connecting wires with a diameter of less than 1 mm by twisting

Let's consider twisting thin conductors using the example of splicing twisted pair cables for computer networks. For twisting, thin conductors are stripped of insulation for a length of thirty diameters with a shift relative to adjacent conductors and then twisted in the same way as thick ones. The conductors must wrap each other at least 5 times. Then the twists are bent in half with tweezers. This technique increases mechanical strength and reduces the physical size of the twist.

As you can see, all eight conductors are connected by twisting with a shift, which makes it possible to do without isolating each of them separately.

All that remains is to tuck the conductors into the cable sheath. Before refueling, to make it more convenient, you can tighten the conductors with a roll of insulating tape.

All that remains is to secure the cable sheath with insulating tape and the twist connection is complete.

Connecting copper wires in any combination by soldering

When connecting and repairing electrical appliances, you have to lengthen and connect wires with different cross-sections in almost any combination. Let's consider the case of connecting two stranded conductors with different cross-sections and number of cores. One wire has 6 conductors with a diameter of 0.1 mm, and the second has 12 conductors with a diameter of 0.3 mm. Such thin wires cannot be reliably connected with simple twisting.

With the shift, you need to remove the insulation from the conductors. The wires are tinned with solder, and then the smaller gauge wire is wound around the larger gauge wire. It is enough to wind a few turns. The twisting area is soldered with solder. If a direct connection of wires is required, the thinner wire is bent and then the connection is insulated.

Using the same technology, a thin stranded wire is connected to a single-core wire with a larger cross-section.

As is obvious, using the technology described above, you can connect any copper wires of any electrical circuits. At the same time, we must not forget that the permissible current strength will be determined by the cross-section of the thinnest wire.

TV coaxial cable connection

There are three ways to extend or splice a coaxial television cable:
– TV extension cable, commercially available from 2 to 20 meters
– using an adapter TV F socket - F socket;
- soldering with a soldering iron.

Tinsel wire connection
twisted with single-core or stranded conductor

If it is necessary to give the cord very high flexibility and at the same time greater durability, the wires are made using a special technology. Its essence lies in winding very thin copper ribbons onto a cotton thread. This kind of wire is called tinsel.

The name is borrowed from tailors. Gold tinsel is used to embroider the ceremonial uniforms of high-ranking military officers, coats of arms and much more. Copper tinsel wires are currently used in the production of high-quality products - headphones, landline phones, that is, when the cord is subjected to intense bending during use of the product.

In a cord of tinsel conductors, as a rule, there are several and they are twisted together. It is almost impossible to solder such a conductor. To attach tinsel to the contacts of products, the ends of the conductors are crimped into the terminals with a special tool. To make a reliable and mechanically strong twist connection without tools, you can use the following technology.

The insulation is removed from the 10-15 mm tinsel conductors and the conductors with which it is necessary to connect the tinsel to a length of 20-25 mm with a shift using a knife in the manner described in the site article “Preparing wires for installation”. The tinsel thread is not removed.

Then the wires and the cord are applied to each other, the tinsel is bent along the conductor and the wire core is tightly wound onto the tinsel pressed against the insulation. It is enough to make three to five revolutions. Next, the second conductor is twisted. You will get a fairly strong twist with a shift. Several turns of insulating tape are wound and the twisted connection of the tinsel to a single-core wire is ready. Thanks to shear twisting technology, the connections do not need to be separately insulated. If you have a heat-shrinkable or polyvinyl chloride tube of a suitable diameter, you can put on a piece of it instead of insulating tape.

If you want to get a straight connection, you need to rotate the single-core wire 180° before insulating it. The mechanical strength of the twist will be greater. The connection of two cords with tinsel-type conductors to each other is carried out using the technology described above, only for wrapping, a piece of copper wire with a diameter of about 0.3-0.5 mm is taken and at least 8 turns must be made.

It would seem that what could be simpler than connecting wires? After all, there are several ways to connect wires. This includes twisting wires, soldering wires, welding wires, crimping and connecting wires using a terminal block. Even a schoolchild knows the easiest way to twist conductors. You need to put the ends of the metal wires, called strands, together and twist them into one “pigtail”, and then wrap them with electrical tape. There is no need for a soldering iron, terminal block, connecting caps and other “unnecessaries”.
Any “own electrician” has mastered this operation. And, when the need arises, he applies this method in his daily practice. For example, it splices the power cord wires of a household appliance, tablet or computer adapter after a break.
Russian “technicians” use this technology for fastening wires everywhere. It’s just that the rules for constructing electrical installations of PES do not provide for “twisting”, all kinds of “bends” and “rivets”. There are no such electrical installation methods in other regulatory documents. Why?

We often don’t think about the consequences of such a “simplification”. Meanwhile, an unreliable contact will fail at the most inopportune moment; the power supply to consumers/power receivers can always be cut off. Voltage “surges” cause breakdown of the elements of the power cascades of complex SBT household appliances. Even special protection devices used in the most “sophisticated” models of foreign manufacturers cannot save you from breakdown.

The induction of short electromagnetic pulses with a voltage of several thousand volts onto the electronic filling causes “harmless” sparking at the joints. At the same time, the standard protection equipment with which apartments are now equipped (RCDs, circuit breakers, fuses) do not “see” such short low-current pulses, so they simply do not trigger them, and we do not accept installing special devices for this. Uninterruptible power supplies for computers also did not become a panacea for transient impulses. The occurrence of “poke” causes malfunctions in the operation of electronic equipment and computer equipment, leading to failure of electrical components and expensive functional modules.
Overheating at the site of a poor connection leads to even more catastrophic consequences; when current passes, the weakened connecting node becomes red-hot. This often causes fires and fires, causing enormous damage to the owners of the premises. Statistics show that 90% of all electrical wiring faults occur due to twists and poor contact connections of conductors. In turn, the very malfunction of electrical wiring and equipment, according to the Ministry of Emergency Situations, is the cause of one third of the fires that occur in Russia.

However, it so happened historically that several decades ago, in conditions of a shortage of electrical accessories/copper conductors, twisting aluminum wires was considered the main method used in electrical installation work. Twisting as a connection can be used in electrical engineering when carrying out repair and restoration work.

How to connect wires correctly

How to connect the wires: we start by removing the insulation. Correct connection of conductors must satisfy three basic requirements:

Ensure reliable contact with a minimum transition resistance between each other, close to the resistance of a single piece of wire.
Maintain tensile strength, fracture resistance and vibration resistance.
Connect only homogeneous metals (copper to copper, aluminum to aluminum).

There are several connection methods that satisfy these requirements. Depending on the requirements for electrical wiring and the possibilities of practical application, the following types of wire connections are used:

All these methods require preliminary preparation of the wire or cable - stripping the insulation to expose the connected cores. Traditionally, rubber, polystyrene, and fluoroplastic are used as insulating shell materials. Additionally, polyethylene, silk and varnish serve as insulation inside. Depending on the structure of the conductive part, the wire can be single-core or multi-core.
By single-core is meant a wire whose cross-section is formed by an insulating sheath with a metal core or wiring inside.

In a stranded wire, the metal core is formed by several thin wires. They are usually intertwined and represent a lay, surrounded on the outside by an insulator. Often, individual wires are coated with polyurethane varnish, and nylon threads are added to the structure between them to increase the strength of the wire. These materials, like the fabric braid on the outside, complicate the process of removing the insulation.

Depending on the type of connection, 0.2–5.0 cm of insulation is removed from each end of the wire. Several types of tools are used for this.
Using a 5-point system, you can evaluate the quality of insulation removal and the degree of protection against cutting - damage to cores by each device:

Damage to insulation/core

Monter (kitchen) knife – 3/3
Side cutters (nippers) - 4/3
Stripper - 5/4
Soldering iron or electric loop burner - 4/4

In low-current television/computer networks, coaxial cables are used. During the cutting process, it is important to carefully cut and remove the insulating jacket without damaging the shielding braid. To access the central vein, it is fluffed up and removed, exposing the trunk. After which the polyethylene insulation is cut with a knife or a special device, the trim is removed from the core.
The bifilar in the screen consists of a pair of wires in the screen, which, in order to access the conductors, is also pre-fluffed into wires, allowing access to each core.

Important! To remove the insulating material of an enameled wire with a cross-section of less than 0.2 mm², a soldering iron should be used. The enamel is carefully removed using sandpaper and moving the paper along the wires.

How to twist wires correctly

Most often, twisting is used in the repair of electrical wiring, cords and adapters (including low-current) household appliances and equipment. If we are talking about the home electrical network, then the standards provide for the use in homes of wires with a current-carrying core cross-section of 1.5–2.0 mm made of copper and 2.5–4.0 mm made of aluminum. Typically, wires of the VVG and PV brands in a polyvinyl chloride sheath are used for wiring. Power cords of the ShVL and ShTB brands with rubber or PVC insulation have a cross-section of 0.5 - 0.75 mm.
You can splice the wires together step by step as follows:

Degrease the bare ends of the wires by wiping with acetone/alcohol.
We remove the varnish layer or oxide film by sanding the conductors with sandpaper.
Apply the ends so that they intersect. We wind clockwise at least 5 turns of one core onto another. To make the twist tight, use pliers.
We insulate the open current-carrying parts of the wires using electrical tape, or screw on an insulating cap. They should extend beyond the insulation for 1.5–2.0 s to cover the exposed areas of the conductors.

To splice a stranded stripped wire with a single-core wire, another winding technique is used:

A single wire is wrapped with a stranded wire, leaving the end free without winding.
The end of the single-core wire is bent 180° so that it presses the twist, then pressed with pliers.
The connection point must be firmly fixed with electrical tape. For best performance, an insulated heat pipe should be used. To do this, a piece of cambric of the required length is pulled over the connection. To make it grip the wiring more tightly, the tube should be heated, for example, with a hair dryer or lighter.

With a bandage connection, the free ends are placed next to each other and wrapped on top with an existing piece of wire (bandage) made of a homogeneous material.
Coupling with a groove provides that before mutual twisting, small hooks are configured from the ends of the wire, they are interconnected, then the edges are wrapped.
There are more complex varieties of parallel/serial connections. Connecting wires using the twisting method is used by professional electrical repairmen when carrying out restoration work.

Important! Copper and aluminum have different ohmic resistances; when they interact, they actively oxidize; due to different hardnesses, the connection turns out to be fragile, so the connection of these metals is undesirable. In case of emergency, the ends to be connected should be prepared - tinned with tin-lead solder (PLS) using a soldering iron.

Why is it better to crimp (crimp) wires?

Wire crimping is one of the most reliable and high-quality methods of mechanical connections currently used. With this technology, loops of wires and cables are crimped into a connecting sleeve using press pliers, ensuring tight contact along the entire length.

The sleeve is a hollow tube and can be made independently. For liner sizes up to 120 mm², mechanical pliers are used. For large sections, products with a hydraulic punch are used.

When compressed, the sleeve usually takes the shape of a hexagon; sometimes local indentation is made in certain parts of the tube. In crimping, sleeves made of electrical copper GM and aluminum tubes GA are used. This method allows for crimping conductors made of different metals. This is largely facilitated by the treatment of the constituent components with quartz-vaseline lubricant, which prevents subsequent oxidation. For joint use, there are combined aluminum-copper sleeves or tinned copper sleeves GAM and GML. Wire connections using the crimp method are used for conductor bundles with a total cross-sectional diameter between 10 mm² and 3 cm².

Soldering as a reliable alternative to twisting

The closest alternative to twisting, which is prohibited for electrical installation, is to connect wires using the soldering method. It requires special tools and consumables, but provides absolute electrical contact.

Advice! Overlapping wire soldering is considered the most unreliable in technology. During operation, the solder crumbles and the connection opens. Therefore, before soldering, apply a bandage, wrap a piece of wire of a smaller diameter around the parts being connected, or twist the conductors together.

You will need an electric soldering iron with a power of 60–100 W, a stand and tweezers (pliers). The soldering iron tip should be cleaned of scale, sharpened, having first selected the most suitable shape of the tip in the form of a spatula, and the body of the device should be connected to the ground wire. Among the “consumables” you will need POS-40, POS-60 solder from tin and lead, rosin as a flux. You can use solder wire with rosin placed inside the structure.

If you need to solder steel, brass or aluminum, you will need a special soldering acid.

Important! Do not overheat the junction points. To prevent the insulation from melting when soldering, be sure to use a heat sink. To do this, hold the bare wire between the heating point and the insulation with tweezers or needle-nose pliers.

The wires stripped of insulation should be tinned, for which the tips heated with a soldering iron are placed in a piece of rosin; they should be covered with a brown-transparent layer of flux.
We place the tip of the soldering iron tip into the solder, grab a drop of molten solder and evenly process the wires one by one, turning and moving along the tip blade.
Attach or twist the wires together, securing them motionless. Warm up with the tip for 2–5 s. Treat the areas to be soldered with a layer of solder, allowing the drop to spread over the surfaces. Turn over the wires to be connected and repeat the operation on the reverse side.
After cooling, the soldering joints are insulated in the same way as twisting. In some compounds, they are pre-treated with a brush dipped in alcohol and coated with varnish.

Advice! During and after soldering for 5–8 s. The wires cannot be pulled or moved, they must be in a stationary position. A signal that the structure has hardened is when the solder surface acquires a matte tint (it shines in the molten state).

But welding is still preferable

In terms of connection strength and contact quality, welding surpasses all other technologies. Recently, portable welding inverters have appeared that can be transported to the most inaccessible places. Such devices are easily held on the welder's shoulder using a belt. This allows you to work in hard-to-reach places, for example, welding from a stepladder in a distribution box. To weld metal cores, carbon pencils or copper-plated electrodes are inserted into the holder of the welding machine.

The main disadvantage of welding technology - overheating of the parts being welded and melting of the insulation - is eliminated using:

Correct adjustment of the welding current 70–120 A without overheating (depending on the number of welded wires with a cross-section from 1.5 to 2.0 mm).
The duration of the welding process is no more than 1–2 seconds.
Tightly pre-twist the wires and install a copper heat sink clamp.

When connecting wires by welding, the twisted wires should be bent and the cut side must be turned upward. An electrode is brought to the end of the wires connected to ground and the electric arc is ignited. The molten copper flows down in a ball and covers the twisted wire with a sheath. During the cooling process, an insulating belt made from a piece of cambric or other insulating material is put on the warm structure. Lacquered fabric is also suitable as an insulating material.

Terminal blocks are the most ergonomic electrical installation products

The PUE rules, clause 2.1.21 provide for the type of connections using clamps (screws, bolts). There is a connection directly using hanging fasteners, when a screw and washer are threaded through the loops of each wire and secured with a nut on the reverse side.

This installation is wrapped with several turns of electrical tape and is considered quite practical and reliable.
Electrical installation products called screw terminal blocks are more ergonomic. They represent a contact group housed in a housing made of insulating material (plastic, porcelain). The most common way to connect wires using terminal blocks is in junction boxes and electrical panels. To connect the wire, you need to insert it into the socket and tighten the screw; the clamping bar will securely fasten the wire to the seat. Another connecting wire is connected to the mating socket, short-circuited with the first one.

In self-clamping terminal blocks of the WAGO type, the wire is snapped into the socket; for better contact, a special paste or gel is used.

Branch clamps are a permanent version of a screw terminal block with several short-circuited taps; they are used mainly outdoors and in places with unfavorable environmental conditions.

The connecting clamps are an insulating cap with a thread inside; it is screwed onto the twist, simultaneously compressing and protecting from mechanical stress.

Connecting electrical wires by twisting

Connecting electrical wires by soldering

If you need to connect a pair of wires and the twisted conductors must be directed in different directions, then a slightly different type of twist is used.

To obtain a reliable and beautiful connection, it is necessary to adjust the lengths of the ends of the conductors with a shift of 2-3 cm.

Twist the conductors in pairs. With this type of twisting, two turns are enough for a single-core wire, and five for a multi-core wire.