How to connect contacts. Correct connection of electrical wires to each other. About junction box

It would seem that it could be easier connection wires? After all, there are several ways to connect wires. These are twisting wires, soldering wires, welding wires, crimping and connecting wires using a terminal block. Even a schoolboy knows the simplest way to twist conductors. It is necessary to attach together the ends of metal wires, called strands, and twist into one "pigtail", then wrap it with electrical tape. No need for a soldering iron, terminal block, connecting caps and other "unnecessities".
Any “electrician for himself” has mastered such an operation. And, if necessary, he uses this method in his daily practice. For example, it splices the wires of the power cord of a household appliance, tablet adapter or computer after a break.
Russian "techies" use this technology for fastening wires everywhere. That's just in the rules for the installation of electrical installations of PES "twisting", all kinds of "bends" and "riveting" are not provided. There are no such methods of wiring in other regulatory documents. Why?

We often do not think about the consequences of such a “simplification”. Meanwhile, an unreliable contact will let you down at the most inopportune moment, the power supply to consumers / power consumers can always be interrupted. From the "surges" of voltage, a breakdown of the elements of the power cascades of a complex household appliances SBT. Even special protection devices used in the most "fancy" models of foreign manufacturers do not save from breakage.

The aiming of short electromagnetic pulses with a voltage of several thousand volts on electronic stuffing causes "harmless" sparking at the joints. At the same time, the standard protection equipment that apartments are now equipped with (RCDs, circuit breakers, fuses) “does not see” such short low-current pulses, so they simply do not work from them, and we do not accept to install special devices for this. Uninterruptible power supplies for computers also did not become a panacea for transient impulses. The occurrence of "pokes" causes malfunctions in the operation of electronic equipment and computer equipment, leads to the failure of electrical components and expensive functional modules.
Overheating at the site of a bad connection leads to even more catastrophic consequences, with the passage of current, a weakened connecting node glows red hot. Often, fires and fires occur from this, causing enormous damage to the owners of the premises. Statistics show that 90% of all electrical wiring malfunctions 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 occurring in Russia.

However, it so happened historically that several decades ago, in the context 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 electrics during repair and restoration work.

How to properly connect wires

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

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

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

All these methods require preliminary preparation of a wire or cable - removal of insulation to expose the wires to be connected. Traditionally, the material of the insulating shell is rubber, polystyrene, fluoroplast. 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.
Single-core means a wire, the cross section of which 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 interlaced and represent a strand surrounded on the outside by an insulator. Often, individual veins are coated with polyurethane varnish, and nylon threads are added to the structure between them to increase the strength of the wire. These materials, as well as the fabric braid on the outside, complicate the stripping process.

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

Insulation/core damage

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

In low-voltage 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 fluffs up and is removed, exposing the trunk. After that, the polyethylene insulation is cut with a knife or a special device, the cut 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, opening access to each core.

Important! A soldering iron should be used to remove the insulating material of enameled wire with a cross section of less than 0.2 mm². Enamel is carefully removed with an emery “zero” by moving the paper along the wires.

How to twist the wires correctly

Most often, twisting is used in the repair of electrical wiring, cords and adapters (including low-current ones) of household appliances and equipment. If we are talking about a home electrical network, then the norms provide for the use of wires in houses with a cross section of a current-carrying core of 1.5–2.0 mm from copper and 2.5–4.0 mm from aluminum. Usually, wires of the VVG and PV brands in a PVC sheath are used for wiring. Power cords of ShVL and ShTB brands with rubber or PVC insulation have a cross section of 0.5 - 0.75 mm.
Step-by-step splicing of wires between each other can be done as follows:

Degrease the bare ends of the wires by wiping with acetone / alcohol.
We remove the varnish layer or oxide film by cleaning the conductors with sandpaper.
We put the ends so that they cross. We wind clockwise at least 5 turns of one core onto another. To make the twist tight, use pliers.
We isolate the open current-carrying parts of the wires with electrical tape, or we wind the insulating cap. They should go beyond the insulation for 1.5–2.0 s to cover the exposed sections of the conductors.

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

A stranded wire is wrapped around a single wire, leaving a free end without winding.
The end of the single-core wire is bent 180 ° so that it presses the twist, then it is pressed with pliers.
The connection point must be firmly fixed with electrical tape. For better efficiency an insulating thermotube should be used. For this, a piece of cambric desired length pulled over the connection. To make it tightly grip the wiring, the tube should be warmed up, for example, with a hairdryer or a lighter.

With a bandage connection, the free ends are placed 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 intertwined with each other, then the edges are wrapped.
There are more complex variations of parallel/series connections. The connection of wires by twisting is used by professional electricians when carrying out restoration work.

Important! Copper and aluminum have different ohmic resistance, they are actively oxidized during interaction, the connection is unstable due to different rigidity, therefore the connection of these metals is undesirable. In case of emergency, the tips to be joined should be prepared - irradiated with tin-lead solder (POS) using a soldering iron.

Why is it better to crimp (crimp) the wires

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

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

During compression, the sleeve usually takes the form 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 the crimping of conductors 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. The crimp connection is 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 forbidden for electrical installations, is the connection of wires by soldering. It requires special fixtures and consumables, but provides absolute electrical contact.

Advice! Splicing of wires with an overlap 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 connected parts, or twist the conductors together.

You will need an electric soldering iron with a power of 60-100 W, a stand and tweezers (thin-nose pliers). The tip of the soldering iron should be cleaned of scale and sharpened, having previously selected the most suitable tip shape in the form of a spatula, and connect the body of the device to the ground wire. From the "consumables" you will need solder POS-40, POS-60 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! Connections must not be overheated. Be sure to use a heat sink to prevent the insulation from melting when soldering. To do this, hold the bare wire between the heating point and the insulation with tweezers or thin-nosed pliers.

The cores stripped of insulation should be irradiated, 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 in the solder, grab a drop of the molten one and evenly process the wires one by one, turning and moving along the tip blade.
Attach or twist wires together, fixing motionless. Warm up with a sting for 2–5 s. Treat the areas to be soldered with a layer of solder, allowing the drop to spread over the surfaces. Turn the connected wires over and repeat the operation on the reverse side.
After cooling, the soldering points are isolated by analogy with twisting. In some compounds, they are pre-treated with a brush dipped in alcohol and varnished on top.

Advice! During and after soldering for 5–8 s. the wires must not be pulled and moved, they must be in a fixed position. A signal that the structure has hardened is the acquisition of a matte shade by the surface of the solder (in the molten state it shines).

Still, welding is preferable.

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

The main drawback of welding technology - overheating of the parts to be welded and melting of the insulation is eliminated by:

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

When connecting wires by welding, the twisted cores should be bent and be sure to turn up with a cut. An electrode is brought to the end of the wires connected to the ground and an electric arc is ignited. The molten copper flows down in a ball and covers the wire strand with a sheath. In the process of cooling, an insulating belt made of a piece of cambric or other insulating material is put on the warm structure. Lakotkan is also suitable as an insulating material.

Terminal blocks - the most ergonomic electrical installation products

The rules of the PUE, clause 2.1.21, provide for the type of connections using clamps (screws, bolts). There is a connection directly with the help of fasteners “on the fly”, when a screw, a washer is threaded through the loops of each of the wires and fixed with a nut on the reverse side.

Such an installation is wrapped with several turns of electrical tape and is considered quite practical and reliable.
More ergonomic wiring products, called screw terminals. They represent a contact group placed in a housing made of insulating material (plastic, porcelain). Most often, the connection of wires using the terminal blocks is found in junction boxes and switchboards. To connect the wire, you need to put it into the socket and tighten the screw, clamping bar securely fasten the core to seat. Another connected wire is connected to the reciprocal socket, shorted with the first one.

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

Branch clamps are a major version of the screw terminal with several shorted taps, they are used mainly in the street and places with adverse environmental conditions.

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

First of all, you must understand that different types of connections can be used in different conditions. And their choice depends on the specific task.

For example, it is much more convenient to connect wires of small cross sections up to 2.5 mm2 in a compact junction box with terminal blocks or clamps. But if we are talking about a strobe or a cable channel, then sleeves come out on top here.

Consider the three most simple and at the same time reliable types of connections.

Let's start with a PPE type connection. It is decoded as:

WITH connecting

AND insulating

W excitement

It looks like a simple cap. There are different colors.

Moreover, each color means belonging to specific sections of the veins.

Cores are inserted into this cap and twisted together.

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

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

On top of that, with a spring-loaded contact that does not allow it to loosen.

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

The next view is the Wago terminal blocks. They are also different sizes, and for a different number of connected wires - two, three, five, eight.

They can join together both monocores and stranded wires.

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

For multi-wire, the clamp should have a latch-flag, which, when open, allows you to easily insert the wire and clamp it inside after snapping.

These terminal blocks in home wiring, according to the manufacturer, can easily withstand loads up to 24A (light, sockets).

There are separate compact specimens on 32A-41A.

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

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

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

When you measure the load on such clamps, 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 your Vago clamps are original, and not a Chinese fake, and at the same time the line is protected by a circuit breaker with a correctly selected setting, then this type of connection can rightly be called the simplest, most modern and easy to install.

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

Therefore, you do not need to set wago to 24A and at the same time protect such wiring with an automatic 25A. The contact in this case will burn out during overload.

Always choose the right vago terminal blocks.

Automatic machines, as a rule, you already have, and they protect primarily the electrical wiring, and not the load and the end user.

There are also enough old view 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 happens under different sections and various shapes.

Here are their technical characteristics (current, cross section, dimensions, screw torque):

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

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

Such a screw connection is well suited for solid conductors, 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 on the network where, as an experiment, the transient resistances on different types of connections are measured with a microohmmeter.

Surprisingly, the smallest value is obtained for screw terminals.

But we should not forget that this experiment refers to "fresh contacts". And try to make the same measurements after a year or two of intensive use. The results will be completely different.

Combination of copper and aluminum

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

An oxide film is formed, resistance increases, and heating occurs. Here it is recommended to use 3 options to avoid this:

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

The contacts are separated from each other in separate cells, plus the paste prevents air from entering 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 ilza

M single

L narrowed

To connect pure aluminum - GA (aluminum sleeve):

For the transition from copper to aluminum, special GAM transitions:

What is the pressing method? Everything is quite simple. Take two conductors, strip to the required distance.

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

With 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 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 right size of the sleeve.

For example, when connecting monofilament, the sleeve is usually taken to the size of a smaller section.

And in this way, you can connect several conductors at the same time at the same point. 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 in” this free space with additional pieces of the same wire, or conductors of a smaller cross section.

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

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

Of course, you will not use either PPE or Wago for these purposes, but the GML sleeves are the very thing! At the same time, everything comes out compactly and easily decreases even in a strobe, even 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 not always, even with its help, it is possible to connect an aluminum solid wire with a flexible copper stranded wire. In addition, you are forever tied to an outlet or extension cord.

And if there is no voltage or generator nearby at all?

At the same time, elementary press tongs, on the contrary, are present in 90% of electrical installers. It is not necessary to purchase the most expensive and fancy ones for this.

For example, batteries. Convenient of course, go and just press the button.

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

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, copper wires with a diameter of 1.6 mm and 2 mm are connected. In this case, the maximum load current on the 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.

Twisting electrical wires

Until recently, twisting was the most common way to connect wires when making electrical wiring, due to availability, it was enough to have a knife and pliers from the tool. But, according to statistics, twisting is an unreliable way to connect conductors.

According to the rules for the installation of electrical installations (PUE), the connection of the type of twist during the installation of electrical wiring is prohibited. But, despite the noted shortcomings, the twisting method is currently widely used. The twisted connection of conductors of low-current circuits, subject to certain rules, is fully justified.

The photo on the left shows how it is unacceptable to twist. If one conductor is wrapped around another, then the mechanical strength of such a connection will be insufficient. When twisting wires, it is necessary to make at least three turns of wires around each other. In the middle photo, the twisting is done correctly, but the copper conductor is twisted with aluminum, which is not acceptable, since when copper contacts 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, it happens that 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 must be made single-core, after being soldered 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 wire twists, except for aluminum and tinsel, when the conductors are tinned before twisting and then soldered with solder, will be reliable on a par with solid wires. The only downside is the extra work involved, but it's worth it.

If you need to connect a pair of wires and the conductors from the twist should 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 more beautiful connection by twisting both single-core and stranded 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 the 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.

Perform pairwise twisting of the conductors. With this type of twisting, two turns are enough for a single-core wire, and five for a stranded wire.

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

Due to the shift of the twist points, it is not necessary to isolate each of the connections separately. We attach on both sides along the conductors along a strip of insulating tape. In conclusion, 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 into the wall and plastered on top. Before laying, it is desirable to protect the connection with a vinyl chloride tube, dressed in advance on one of the pairs of wires. I have done this several 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 to make repairs, I immediately encountered the flashing of lighting bulbs in time with hammer blows on the walls. There was a primary task of repair, revision of junction boxes. Opening them showed the presence of poor contact in the twists of copper wires. To restore contact, it was necessary to disconnect the twists, clean the ends of the wires with sandpaper and twist again.

When trying to disconnect, I ran into 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 obviously cut with a knife blade in a circle and notches were made. In these places, the wire broke off. Copper hardened from temperature fluctuations.

To return copper elasticity, unlike ferrous metals, you can heat it to red and quickly cool it. But for this case, such an approach is unacceptable. The ends of the wires were no more than 4 cm long. There was no choice for the connection. Only solder.

I stripped 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 wiring is de-energized? The answer is simple, using a battery powered soldering iron.

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

When leveling the walls with Rotband in the hallway and installing a stretch ceiling, the junction boxes became a hindrance. I had to open them all, and the reliability of the solder joint was confirmed, they were in perfect condition. So I boldly hid all the boxes in the wall.

The connections currently practiced with the help of a Wago flat spring clamp terminal block greatly reduce the time spent on installation work, but are much inferior in reliability to solder connections. And in the absence of spring-loaded contacts in the block, they completely make connections in high-current circuits unreliable.

Mechanical connection of wires

Soldering is the most reliable type of connection of wires and contacts. But it has disadvantages - the inseparability of the obtained connections and the high labor intensity of the work. Therefore, the most common type of connection of wires with electrical contacts of devices is threaded, screws or nuts. For the reliability of this type of connection, it is necessary to perform them correctly.

The linear expansion from temperature changes is different for metals. Aluminum changes the linear dimensions especially strongly, then in descending order, brass, copper, iron. Therefore, over time, a gap is formed between the contact of the connected metals, which increases the resistance of the contact. As a result, to ensure the reliability of the connections, it is necessary to tighten the screws periodically.

In order to forget about maintenance, additional washers with a cut are installed under the screws, which are called split washers or Grover. The grower selects the resulting gaps and thus ensures a high contact reliability.

Often, electricians are lazy, and the end of the wire is not twisted into a ring. In this embodiment, the area of contact of the wire with the contact pad of the electrical appliance will be many times smaller, which reduces the reliability of the contact.

If the formed wire ring is slightly flattened with a hammer on the anvil, then 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, flatness can be given with a needle file by grinding off a little ring at the points of contact with the contacts.

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

Sometimes it is required to connect copper and aluminum conductors to 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 for 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 of the same metal or when connecting an aluminum wire to a copper wire, the end of which is tinned, then it is not necessary to lay a washer between the rings of the conductors. If the copper wire is stranded, then it must first be soldered.

Connecting wires with a terminal block

The connection of wires with a low current load can be performed using terminal blocks. Structurally, all terminal blocks are arranged in the same way. Thick-walled brass tubes with two threaded holes on the sides of each are inserted into the combs of the body made of plastic or carbolite. Connected wires are inserted into opposite ends of the tube and fixed.

The tubes come in different diameters and they are selected depending on the diameters of the connected conductors. As many wires can be inserted 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 wiring. The indisputable advantage of terminal blocks is the ability to connect in electrical wiring copper and aluminum wires, as brass tubes are plated with chromium or nickel.

When choosing a terminal block, it is necessary to take into account the current that will pass through the switched wires of the electrical wiring and required amount terminals in the comb. Long combs can be cut into several short ones.

Connecting wires using a terminal block
with flat spring clip Wago

Terminal blocks with a flat spring clip Wago (Vago) of 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 allows you to easily insert and remove the wires.

The photo shows a Wago disposable terminal block. It is designed to connect any type of single-core wires, including copper and aluminum wires with a cross section of 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 that it is not worth loading the Wago terminals with a current of more than 10 A.

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

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

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

The Wago terminal block is modern means Tool-free wire connections are quick and reliable, but more expensive than traditional connection methods.

Permanent connection of wires

In some cases, when it is not supposed to switch the wires in the future, they can be connected in an integral 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.

Connection of 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, depending on the metal of the wires being connected, and the tube is pressed in the middle with a tool called press tongs.

Crimping can 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 reliability of the connection will be high. If in a stranded wire the conductors are interconnected, then it is necessary to develop and straighten them. It is not necessary to twist the wire strands together. The prepared conductors are inserted into the tube and crimped with press tongs. The connection is ready. It remains only to insulate the connection.

Crimping lugs are commercially available 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, it deforms during crimping and is securely held, providing reliable insulation connections.

The disadvantage of the connection by crimping should include the need for special press - tongs. Ticks can also be made independently from pliers with side cutters. It is necessary to round the side cutter blades and make a groove in the middle. After such refinement of the pliers, the edges of the side cutters will become blunt and will no longer be able to bite, but only squeeze.

Connection of wires of a larger cross-section by crimping

To connect electrical wires of a larger cross section, for example, in power shields of houses, special lugs are used, which are crimped using universal press tongs, such as PK, PKG, PMK and PKG.

For crimping each size of the tip or sleeve, its own die and punch are required, a set of which is usually included in the set of pliers.

To crimp the tip onto the wire, the insulation is first removed from the wire, the wire is threaded into the hole of the tip and wound between the matrix and the punch. For the long handles of the press tongs are compressed. The tip is deformed, compressing the wire.

In order to choose the right matrix and punch for the wire, they are usually marked and the branded press tongs on the matrix have an engraving for crimping which section of the wire the matrix is intended for. The number 95 embossed on the tip means that this matrix is designed for crimping in the tip of the wire with a cross section of 95 mm 2.

Connecting wires with a rivet

It is carried out using screw connection technology, only a rivet is used instead of a screw. The disadvantages include the impossibility of disassembly and the need for a special tool.

The photo shows an example for connecting copper and aluminum conductors. For more information about connecting copper and aluminum conductors, see the site article "Connecting aluminum wires". In order to connect the conductors with a rivet, you first need to put an aluminum conductor on the rivet, then a spring washer, then a copper and a flat washer. Insert the steel rod into the riveter and squeeze its handles until it clicks (this is cutting off the excess steel rod).

When connecting conductors made of the same metal, it is not necessary to lay a split washer (Grover) between them, but put the Grover on the rivet first or penultimate, the last must be an ordinary washer.

Connecting broken wires in the wall

Repairs should begin with a very careful removal of plaster in the area of \u200b\u200bdamaged wires. This work is done with a chisel and a hammer. As a chisel when laying electrical wiring in the wall, I usually use the rod from a broken screwdriver with a sharply sharpened end of the blade.

Connection of copper wires interrupted in the wall

A piece of copper wire is taken, with a cross section not 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 should provide an overlap on the connected ends of the wires by at least 10 mm.

The insert is soldered with the connected ends. Solder should not be saved. Next, the insulating tube is shifted in such a way as to completely close the junction. If a sealed moisture-resistant connection is required, then before putting on the tube, the soldered connection must be coated with silicone.

Connection of aluminum wires interrupted in the wall

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

Step-by-step instructions for connecting broken wires in the wall are described in the article "Connecting broken wires in the wall"

Connecting wires with push-on terminals

Detachable connection of conductors with the help of captive terminals, which are put on contacts with a thickness of 0.8 and a width of 6.5 mm, are widely used in household appliances and cars. The reliability of fixing 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 there is not always a new replacement terminal on hand. You can successfully use a used one by mounting the terminal using the following technology.

First you need to prepare the old terminal for re-assembly. To do this, holding the terminal with pliers at the place of pressing, you need to spread the antennae that compress the insulation with an awl or a screwdriver with a thin sting. Further, the wire is repeatedly bent, until it breaks at the exit point from the pressing. To speed up, you can cut this place with a knife.

When the wire is separated from the terminal, a place is prepared with a needle file for soldering it. It is possible to completely grind off until the remaining wire is released, but this is not necessary. It turns out a flat area.

The resulting site breaks through with solder. The conductor is also cleaned and tinned with solder using a soldering iron.

It remains to attach the conductor to the prepared terminal site 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.

It remains to pull on the insulating cap, put the terminal on the desired contact and check the reliability of fixation by pulling the wire. If the terminal jumped off, then it is necessary to tighten its contacts. A self-made soldered terminal on a wire is much more reliable than one obtained by crimping. Sometimes the cap is worn so tightly that it cannot be removed. Then it must be cut and, after mounting the terminal, cover it with insulating tape. You can also stretch a piece of vinyl chloride or heat-shrinkable tubing.

By the way, if you hold a PVC tube for five minutes in acetone, then it increases in size by one and a half times and becomes plastic, like rubber. After evaporation of acetone from its pores, the tube returns to its original size. In this way, about 30 years ago, I isolated the base of light bulbs in a Christmas tree garland. So far, the insulation is in excellent condition. I still hang this garland of 120 6.3 V bulbs on the Christmas tree every year.

Splicing stranded wires without twisting

You can splice stranded wires in the same way as single-core ones. But there is a more perfect way, in which the connection is more accurate. First you need to adjust the length 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 must be pulled together with a thin wire before soldering. Then lubricate with soldering varnish and solder with solder.

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

This is what the connection looks like after being covered with electrical tape. Can be further improved appearance, if you sharpen the places of soldering with a needle file from the side of the insulation of adjacent conductors.

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

Connecting wires with a diameter of less than 1 mm with a twist

We will consider the twisting of thin conductors using the example of splicing a twisted-pair cable for computer networks. For twisting, thin conductors are released from insulation for a length of thirty diameters with a shift relative to neighboring conductors and then twisted in the same way as thick ones. Conductors must wrap themselves around each other at least 5 times. Then the twists are bent in half with tweezers. This technique increases the mechanical strength and reduces the physical size of the twist.

As you can see, all eight conductors are connected with a sheared twist, which eliminates the need to insulate each of them individually.

It remains to fill the conductors in the cable sheath. Before refueling, to make it more convenient, you can pull the conductors with a coil of insulating tape.

It remains to fix the cable sheath with insulating tape and the twist connection is completed.

Connection of copper wires in any combination by soldering

When connecting and repairing electrical appliances, it is necessary to lengthen and connect wires with different cross-sections in almost any combination. 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 a simple twist.

With a shift, you need to remove the insulation from the conductors. The wires are tinned with solder, and then the smaller wire is wound around the larger wire. It is enough to wind a few turns. The place of twisting is soldered with solder. If you want to get a direct connection of wires, then the thinner wire is bent and then the junction 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 from the above technology, you can connect any copper wires of any electrical circuits. At the same time, one should not forget that the permissible current strength will be determined by the cross section of the thinnest wire.

TV coaxial cable connection

It is possible to extend or splice a coaxial television cable in three ways:
- TV extension cable, on sale are from 2 to 20 meters
– using an adapter TV F socket - F socket;
- soldering with a soldering iron.

Tinsel wire connection
stranded with solid or stranded conductor

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

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

As a rule, there are several conductors of tinsel in the cord, and they are twisted together. Soldering such a conductor is almost impossible. To connect the tinsel to the contacts of the products, the ends of the conductors are crimped into the terminals with a special tool. To perform a reliable and mechanically strong connection by twisting without a tool, you can use the following technology.

10-15 mm tinsel conductors and conductors with which it is required to connect tinsel to a length of 20-25 mm with a shift with a knife in the manner described in the site article "Preparing wires for installation" are released from insulation. 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 core of the wire is tightly wound onto the tinsel pressed against the insulation. It is enough to make three to five turns. Next, the second conductor is twisted. You will get a fairly strong twist with a shift. Several turns are wound with insulating tape and the connection of tinsel with a single-core wire is ready. Thanks to shear technology, the connections do not need to be insulated individually. If you have a heat-shrinkable or PVC tube of a suitable diameter, you can put on a piece of it instead of an insulating tape.

If you want to get a straight connection, then you need to turn the single-core wire by 180 ° before insulating. In this case, the mechanical strength of the twist will be greater. The connection of two cords with tinsel-type conductors to each other is carried out according to 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.

In order for the power supply in your homes to always be of high quality, uninterrupted and reliable, it is very important to correctly connect the wires during installation work. There are a lot of ways, we will consider each one in detail with its advantages and disadvantages, with step by step instructions performing switching. We will also pay attention to the eternal question of electricians - how to connect wires whose cores are made of different metals (for example, copper and aluminum).

Removing the insulating layer from the wires

Immediately I would like to dwell on a question that will be common to any method. Before connecting the wires into a common electrical unit, they must be stripped from the upper insulating layer.

This can be done with a utility knife. This method is simple, but there is a high probability of damage to the conductive core. To do everything right, you must clearly follow the step-by-step instructions:

Place the wire on some flat surface(table type).
Press it with the index finger of your left hand.
Right hand take a knife and lightly press it into the insulating sheath of the wire. In order not to hook the metal core, position it towards the cut at an angle. If the angle is right, there is a possibility of a circular notch in the core, as a result of which it may subsequently break.
Holding the knife in this position. index finger With your left hand, slowly turn the conductor one full turn, thus cutting the insulation all around.
It remains only to pull off the cut piece of insulation.

Professional electricians now already have in their arsenal such a device as a stripper. This is a multifunctional tool, with it you can strip the insulation from the wire or cut the cable. It can be simple, semi-automatic and automatic. Most importantly, when stripping the insulation with a stripper, the conductive core is not damaged. For each standard core diameter, such a tool has a calibrated hole with a cutting edge.

The length to which it is necessary to strip the wire cores is different for each connection method.

Twisting

Let's start with the simplest and most well-known method - twisting. It can also be called the oldest, not for nothing that electricians among themselves call twisting the “grandfather method”.

We will not tell you that such a wire connection is durable and reliable. According to the main document in electrical engineering, PUE (“Rules for Electrical Installations”), twisting is generally prohibited, despite the fact that half a century ago it was used everywhere. The fact is that in those days, the load in the apartments consisted only of lighting, radio or TV. Considering the current load in modern apartments with a huge amount of household appliances used daily, then no old insulation, core cross-sections and wire connection methods are no longer suitable.

Nevertheless, we will talk about twisting, and even in the first place, because it is the main stage in such connection options as welding and soldering.

Positive sides

The most important advantage of twisting is that it requires absolutely no material costs. All you need is a knife to remove the insulating layer from the wire strands and pliers to make the connection.

The second indisputable advantage of twisting is ease of execution. No special knowledge or skills are needed, anyone who has ever held pliers in their hands can do it.

In a twist, several wires can be connected at the same time, but their total number should not exceed six.

Negative sides

The main disadvantage of twisting is its unreliability, it weakens over time. This is due to the fact that there is a residual elastic deformation in the cores of the cable or wire. In the place of twisting, the transition resistance increases, which is fraught with a breakdown in contact and heating. In the best case, you will find it in time and re-seal the junction, in the worst case, a fire may occur.

Using twisting, it is impossible to connect electrical wires made of different metals. As an exception, you can twist copper and aluminum wire, but only if the copper core is pre-tinned with solder.

In electrical engineering, there are concepts of a detachable or one-piece connection. So twisting does not apply to either one or the other. A detachable connection is characterized by the fact that its ends can be separated many times. In twisting, this cannot be fully done, each time after the next promotion and twisting of the cores, they will deteriorate. It is also impossible to call twisting an integral connection, because it does not have the concepts of strength, reliability and stability necessary for this. This is another disadvantage of the twisted connection.

Installation

If for some reason you do not have the opportunity to use other methods of connecting electrical wires, you can use twisting, just do it with high quality. Very often it is used as a temporary option and is subsequently replaced by more reliable switching methods.

How to connect wires with a twist? To begin with, the veins are cleaned by 70-80 mm. The main thing is to twist all switched conductors into one single twist at the same time, and not wind one around the other.

Many mistakenly begin to twist the cores together from the place where the insulating layer ends. But it is better to clamp both wires in this place with one pair of pliers, and with the second, grab the ends of the wires and perform rotational movements in a clockwise direction.

If the wire section is small, you can twist it by hand. Align the conductors with the insulation shear and hold them firmly in this place with your left hand. Bend all switched tips into one single bend at an angle of 90 degrees (a bend length of 10-15 mm will be enough). Hold this fold with your right hand and rotate it clockwise. This must be done firmly and firmly. If it is already difficult to twist with your hands at the end, use the pliers, as described above. As soon as the twist becomes even and beautiful, you can cut the bend.

You can also connect several wires in this way, but then, to make it easier to twist them, make the bend longer, somewhere around 20-30 mm.

How to properly twist the wires is shown in this video:

There is also a way to twist wires with a screwdriver, see about it here:

For twisting wires with a special tool, see here:

Now the resulting twist must be carefully insulated. For this, electrical tape is used. Do not spare it, wind it in several layers, and isolate not only the connection itself, but also step 2-3 cm over the insulation of the cores. Thus, you will ensure the insulating reliability of the twist and protect the contact connection from moisture.

You can also insulate the connection of wires with the help of thermotubes. The main thing is not to forget to put the tube on one of the wires to be connected in advance, and then put it on the place of the twist. Under heat, the thermal pipe shrinks, so slightly heat its edges, and it will firmly wrap around the wire, thereby providing reliable insulation.

If the twisting is done with high quality, it is likely that it will serve you for many years, provided that the load current in the network is normal. But still, it is better not to stop at this stage and strengthen the junction by welding or soldering.

Soldering

Soldering is when electrical wires are connected using molten solder. This type of connection is most suitable for copper wires. Although there are now various fluxes for aluminum, experienced electricians prefer to refrain from such soldering. But if necessary, you can use special fluxes and even solder copper with aluminum.