Being engaged in do-it-yourself repair of household appliances or maintenance of electrical wiring, any master is faced with the issue of safe creation electrical circuits by connecting the wires to each other or connecting them to the output terminal blocks.
However, even experienced electricians can make mistakes in ensuring the reliable formation of electrical contacts, which will not appear at the initial moment of operation, but will create a malfunction over time.
The metal of the wire is made to flow perfectly through it. electric current. For this purpose, it is cast from a homogeneous composition of a copper or aluminum alloy with a standard cross section along the entire length.
To create a contact, a simple contact of the surfaces without any effort is enough. The photo below shows that if an open strand of the second wire is placed on one bare area, then an electrical connection is formed between them. Through it, a 4-volt battery can make a light bulb from a flashlight glow.
In home wiring much more - 220 volts. An erroneous conclusion is drawn from this fact: it is easy to create a contact of electrical wires.
Beginning electricians simply forget the issue of providing reliable transient resistance for long-term operation of such a connection.
When mounting the wires, the home master is faced with the need to process:
- conductive core;
- layer of insulation.
These are two interrelated processes that provide the final result - the optimal flow of electric current through the created circuit.
How to work with wire insulation layer
The dielectric coating protects the metal core from the occurrence of unforeseen chains. When it is violated, leakage currents immediately appear, leading to malfunctions.
The insulation layer of the wire may be broken:
- under mechanical influence;
- overheating;
- from solar radiation.
Protection from all these destructive factors is required. Moreover, removing, if necessary, a layer of insulation to connect the wire, it is impossible to damage the surface of the metal core.
To safely perform this job, many tools with cutting edges have been created. Consider their use for home conditions.
electrician's knife
Trade provides a wide range of their designs. Some workers prefer to use knives made with their own hands from materials selected according to their individual characteristics.
When choosing the right model for your needs, pay attention to them, eliminating the possibility of accidental cuts.
The main condition correct operation is the orientation of the blade relative to the axis of the wire. The formed angle must be sharp. Then the knife will cut off the dielectric layer and at the same time slide over the metal without touching it.
Setting the knife perpendicular to the wire will cut through not only the insulation, but also the surface of the metal core. This means that it will reduce its cross section, break the connection, increase the electrical resistance to the passing current, which will cause excessive heating and aging of the dielectric layer.
Deep penetration of a sharp blade into the metal leads to rapid breakage when the wire is bent. Such scratches can be identified by careful visual inspection. But who does it?
A fitter's knife is a common tool for every electrician, but not all home craftsmen have good practical skills in stripping insulation. Yes, and experienced professionals can inadvertently cut the metal and not notice the error.
Therefore, the industry has long been producing tools adapted for these purposes.
Stripping pliers
Their industrial designs have been produced for quite a long time, and the design is constantly being improved. Let's look at them with examples.
rare sample
For the set of tools of the Soviet electrician, combined pliers were produced, allowing:
- safely cut and remove insulation from wires of standard sections 1.5 and 2.5 mm square;
- bite copper veins;
- bend neat rings;
- perform other operations.
They cope with their tasks normally even now, despite their unsightly appearance, slight wear, and heavy weight. To remove the insulation from the ends of the wire, it is enough:
- insert it into the appropriate slot;
- squeeze the handles to cut the insulation;
- ensure axial movement of the jaws towards the end of the wire.
The surface of the metal core is not damaged, it remains in its original state.
The increased gripping force of the handles is compensated by the design of the tongs, it does not create malfunctions.
Modern models
They have much greater technical capabilities, allowing you to work with wires of small and enlarged cross-sections, both with monolithic and stranded conductors.
Made of high-strength plastic, the housing has dielectric properties and is lighter in weight. It is equipped with various controls and accessories.
Such a tool must not only be studied before work, but correctly adjusted for each cross section. Otherwise it will create problems.
Pliers and side cutters
Among electricians there is a category of workers who remove insulation in a similar way. The error of this method is the uncontrolled compressive force of the handles, which leads to squeezing of the metal of the wire, deformation and destruction of its surface.
This error may occur intermittently with a random sequence. It depends on the experience of the employee, his condition, attentiveness and other factors.
It is dangerous to remove insulation in this way, and the places of its removal must be carefully checked. Particular attention should be paid to stranded stranded conductors.
How to work with metal core wire
Methods for creating electrical contacts through wire are based on the use of:
- screw terminals;
- twists;
- soldering or welding;
- spring compression.
Screw connections
The connection can be made:
- pressing the ring;
- pressing the core with a screw directly or through washers.
Making rings
When screwing in the screw, the wire ring should work in compression, and not in spinning. They must be separated by wide washers on each side of the surface. Incorrectly clamped in the form of a ring, the wire may come out of the mount during operation.
This method is considered the most reliable and is widely used in energy enterprises.
Use of terminal blocks
The metal core is inserted into a special socket, held in it by the tightening force of the screw through the surface of the spring steel washer or its threaded end. 
With this method, it is important to observe the nominal value of the screwing force. Weak twisting leads to pulling the wire out of the terminal (you need to check it by hand), and excessive twisting crushes the core.
Wire twisting
The contact surface created between the cores should cover the area with a margin cross section.
For this, the twisted ends with the insulation removed are made of a large length of the order of 10 cm, and their twisting is performed with pliers quite tightly with a uniform distribution of turns.
When twisting, the wires should be well crimped and stretched for reliable contact of the surfaces.
Ways to create an improved twist
The contact resistance of the surface layer contact can be reduced by:
- welding of the terminal section of the connection;
- soldering twisted surface.
Not every home master can apply this technology. For her it is necessary special equipment - welding transformer for copper or aluminum, or . Therefore, in home wiring, twists are immediately covered with electrical tape or insulated with heat shrink tubes.
Typical twist errors
Often, electricians make short ends of the wire, which, under heavy loads, cause increased heating of the contact connection being created.
Insulating caps for connecting wires
Contact is created by compressing the surfaces of each wire by the force of a spiral spring built into the housing.
The metal conductors of the appropriate diameter, cleaned of insulation, are screwed into a spiral, creating a twist. The steel spring expands slightly when the wire ends are inserted and compresses them in the socket.
Errors in wiring with PPE caps
The poor quality of the connection contact arises from:
- inept work of electricians;
- the use of low-quality fakes of branded products;
- erroneous calculation or installation of electrical wiring;
- incorrect and protective shutdown devices.
To prevent possible malfunctions, individual masters increase the surface of the twist, having previously removed a larger layer of insulation than required and make a twist on it. After the PPE cap is screwed in, the exposed area is wrapped with electrical tape or covered with heat shrink tubing, which creates additional compression.
However, this technology is not provided by manufacturers and requires additional actions and time.
Wago terminal blocks
When using them, the electrical contact of the circuit is created by a spring clip controlled by a special lever.
The wire is inserted with a metal core into the socket of the terminal block until it stops with the lever retracted, and then fixed in it simple action. The created contact connection has an acceptable transient resistance, works well at rated loads. It is not worth counting on its reliable operation during prolonged overloads of more than 16 amperes.
The advantage of Vago terminal blocks is the ability to quickly rewire the circuit for its reconstruction. The wires from them in most designs are quickly and easily removed. However, there are disposable models on sale that do not provide the function of re-breaking the created chain.
This connection method is common among our western neighbors. It is well suited for a home craftsman who does everything with his own hands, but does not have sufficient practice to securely connect the wires in other ways.
Features of connecting a flexible wire
Stranded stranded conductors are designed for use in mobile electrical appliances. They withstand bending, twisting well, but do not work well when installed in terminal blocks to create screw or spring contact.
Under the generated compressive force, the individual wires are deformed, and their total twist spreads so that the total cross-sectional area of the wire can decrease.
To prevent this process, metal tips with a dielectric insert of the appropriate diameters are used. After installing a bare core in them, a small crimp is made, creating an electrical contact.
When a stranded wire with such a ferrule is inserted into the terminal block, it is additionally compressed by screw fastening or spring force. As a result, a normal electrical contact is created from all the wires.
Only properly configured protections can prevent the consequences of unnoticed installation errors when switching on under load:
- circuit breakers,
To supplement the material on a reliable connection of wires, in relation to the conditions of home wiring, provides the owner's video "Electrician's Tips" "Pros and Cons". Recommended for viewing.
When connecting wires in series different diameter, the maximum load current will be determined by the wire section 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 performing electrical wiring, due to the 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 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 applied, 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 and with the help of the 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. It changes especially linear dimensions aluminum, further downstream, 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 ideal threaded connection of 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 aluminum wire with copper, 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 copper and aluminum wires in electrical wiring, 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. There are two Wago terminal blocks 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 wires of electrical wiring, 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 a modern means of connecting wires without tools quickly and reliably, but is more expensive than traditional ways connections.
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 expedient 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 isolation of the connection.
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. Per long handles press tongs are compressed. The tip is deformed, compressing the wire.
In order to choose the right die and punch for the wire, they are usually marked and branded press tongs on the die have an engraving for crimping which section of the wire the die 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 segment is taken copper wire, with a cross section not less than the cross section of a 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
Widely used in household appliances and automobiles, detachable connection of conductors using captive terminals, which are put on contacts with a thickness of 0.8 and a width of 6.5 mm. 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. You can still improve the 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 adjacent 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 technology described above, any copper wires of any electrical circuits can be connected. 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.
The conductors of tinsel 10-15 mm and the conductors with which it is required to connect the 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.
First of all, you must understand that in different conditions different types of connections can be used. 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:
- FROM connecting
- And insulating
- Z 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 stranded, the clamp must have a latch-flag, which in open state allows you to easily insert the wire and clamp it inside after it snaps into place. 
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 is also a fairly old type of connection, such as terminal blocks. ZVI - insulated screw clamp.
In appearance, this is a very simple screw connection of wires to each other. Again, it happens under different sections and various shapes.
Here they are specifications(current, 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 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 crimp 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.
Content:
The problem of connecting wires at least once in a lifetime occurred to every person. At the same time, these products are presented in a fairly wide range: aluminum and copper, single-core and multi-core, computer and telephone, power and heating. They are designed for different loads and require special approaches when working. The question arises: how to connect the wires correctly?
The main requirement is to ensure reliable isolation and long service life.
Features of connecting aluminum and copper wires
Traditional twists are not always able to provide the desired result. Especially in the case of connecting copper and aluminum wire.
Before you connect the wires, you should know that aluminum oxidizes over time. As a result, the surface layer has more resistance and starts to heat up. The thermal expansion coefficient of aluminum is higher than that of copper. At the same heating temperature, it needs more space.
As a result, after a certain number of heating and cooling cycles, the contact will weaken so much that overheating and breakage of the connection may occur. This situation is unacceptable from a security point of view.
There are several main types of devices for connecting wires:
- Connecting insulating clamps;
- Screw terminals and junction boxes or blocks;
- Self-clamping terminal blocks and splitters;
- Clamp splitters;
- Electrical connectors with mortise contact;
- Connecting sleeves and tips.
Them practical use requires different approaches and tools.
Connecting insulating clips
Connecting insulating clamps for connecting wires - Photo
Connecting insulating clips or just caps PPE provide simultaneous isolation and fixation of the contact. Applies exclusively to single-core wires.
Before connecting the wires, their ends are twisted clockwise. Inside the cap there is a helical spring that compresses the wires as they are put on. The clamp is screwed onto the contact point also clockwise.
Connecting wires with PPE - Photo
Screw terminals and junction boxes
How to properly connect the wires through the terminal block - Photo
Screw terminals used to connect copper wires. Aluminum is quite soft and ductile material. Under constant pressure, it deforms. As a result, over time, the contact will weaken and begin to warm up.
In addition, screw terminals are not used for stranded wires. Thin veins are torn from uneven load and friction. You need to know this in order to understand how to properly connect the wires.
In practice, the wire is inserted into the brass sleeve of the terminal block and clamped with a screw. For a high-quality connection for each wire section, it is necessary to select the size of the fixture holes.
It should be borne in mind that with too much force, the brass sleeve may burst.
Screw terminal boxes for connecting stranded wires - Photo
AT screw junction box the contact point is also clamped with screws. It is suitable for connecting aluminum and stranded wires. This is possible due to some design differences between the blocks and the terminal blocks. The end of the wire is clamped between two plates. At the same time, the upper one has a surface that allows increasing the contact surface.
How to connect wires - Video
Wago self-clamping terminal blocks for connecting wires - Photo
Self-clamping terminal blocks and splitters designed to connect only single-core copper or aluminum wires. They can reliably connect these two materials to each other. These are disposable products. They are designed with a pressure plate that keeps the end of the wire firmly in contact with the tinned copper busbar and prevents the connection from loosening over time.
Wago terminal blocks for connecting aluminum wires - Photo
The question arises: how to connect aluminum wires using this device? A mixture of quartz sand and technical petroleum jelly is applied to the surface of the pressure plate.
The first serves as an abrasive to remove the oxide film from the aluminum wire, and the second serves to prevent its re-formation. For reliable and long service life of products, it is necessary to comply with the requirement for the maximum calculated value of the current passed through it.
Clip-on splitters for the correct connection of wires
Reusable wire clamp with lever - Photo
Clamp splitters suitable for any kind of wires in any combination. The design of the product includes a plate that presses the end of the wire against the tinned copper busbar.
Unlike self-clamping terminal blocks this compound reusable. Reliable contact is ensured by a special movable lever. It allows you to change the wires and their combinations an unlimited number of times. The product is designed for a maximum current of 35A.
Electrical connectors with mortise contact for connecting wires — Photo
Electrical connectors with mortise contact or scotch locks can only be used in networks with a low load. For example, for phones or LED lamps. This is a disposable product.
The design provides for one or two plates, one of the surfaces of which is cutting-clamping. The interior of the connector is filled with a hydrophobic gel. Its purpose is to protect the contact point from oxidation, moisture and corrosion.
Connecting thin wires with a special clamp - Photo
When used, the wires are inserted into the holes and the adhesive lock snaps into place with a compressive force. The plate cuts through the wire insulation and provides a tight connection.
Connection sleeves for high current conductors
Connecting sleeves for high current wires - Photo
Connection sleeves used for high currents. Suitable for aluminum and copper wires or a combination. The usage is quite simple.
High current crimped wires — Photo
One or more wires are placed inside the sleeve and it is clamped with special pliers. The use of the tool provides a high-quality connection that does not require additional maintenance. There are several types of products:
- To connect the wire to the case when performing grounding, use sleeves with a flat end and a hole in it;
- For single wires, use sleeves with screw clamp;
- For any combination of wires use tinned copper universal sleeves.
Tip for crimping stranded wires - Photo
Tip designed for a secure connection stranded copper wires. On the one hand, it has an extension. Before connecting the copper wires, their ends must be twisted and inserted into the extension. Then the tip is pressed with clamping tongs. In the future, the end of the wire treated in this way can be used in any type of connection.
The main goal pursued when using various means for connecting wires is to ensure their reliable and long-term contact. Knowledge of the purpose and design features of products will help to use them in practice as efficiently as possible.
In private construction, sooner or later there is a need for the installation of electrical networks. Some people turn to specialists for help, others want to do it on their own. The process itself is not very difficult if there are certain skills and knowledge of safety standards, but this mainly concerns the connection of wires of the same section.
But quite often situations arise when it is necessary to reliably connect three or more wires to each other, and all of them have a different cross section. In this regard, the question of how to correctly and safely connect wires of various sections is currently one of the most relevant in the installation of electrical networks.
Methods for connecting wires of various sections
Connecting copper wires of different thicknesses is not the most difficult process. However, for maximum reliability and safety, it is necessary to observe here certain requirements. There are several ways to connect three wires of different cross sections:
- welding or soldering;
- using screw terminals;
- using self-clamping terminals;
- bolted connection;
- branch clamp;
- using copper tips.
Three wires of different cross-sections can be securely connected by any of the above methods, but it is important to remember that when installing sockets and switches, you cannot connect cables of different thicknesses to one contact. In this case, the thinnest of them will not be pressed tightly enough. And this, in turn, can adversely affect the safety of operation.
Connecting wires of different sections by welding or soldering
Easiest but enough reliable way connecting cables that have different thicknesses. In this case, three wires can be connected to each other by hard twisting with subsequent fixation. But here it should be remembered that a reliable connection is possible only between wires of approximately the same cross section. The twisting of wires whose diameters differ significantly cannot be reliable.
Twist three wires of different cross-sections with each other carefully. Each copper core should tightly wrap around the adjacent one. The gaps between them should be minimal. Otherwise, it will affect the safety of subsequent operation.
Before proceeding directly to the twisting of the three wires, lay them out in front of you and sort by thickness. You can not wind a thin wire on a thick one - this will affect the quality of the contact. Such a connection will not last long.
Connection of three wires of different cross-sections using screw terminals
Three wires of different thicknesses can be securely connected to each other using special ZVI screw clamps. Clamps have a very convenient design and allow you to create contact between cables that have different sections. The strength of the connection is achieved by using separate screws for each clamp.
It is necessary to choose ZVI clamps taking into account the cross section of the wires that will be connected, as well as their current load. For reliable contact, it is recommended to connect three wires of adjacent sections. We conditionally designate the cross section of the connected conductors as SPP, and the permissible continuous current as DDT. Below are the parameters of clamps and wires:
- ZVI-3 - SPP 1 - 2.5; DDT - 3;
- ZVI-5 - SPP 1.5 - 4; DDT - 5;
- ZVI-10 - SPP 2.5 - 6; DDT - 10;
- ZVI-15 - SPP 4 - 10; DDT - 15;
- ZVI-20 - SPP 4 - 10; DDT - 20;
- ZVI-30 - SPP 6 - 16; DDT - 30;
- ZVI-60 - SPP 6 - 16; DDT - 60;
- ZVI-80 - SPP 10 - 25; DDT - 80;
- ZVI-100 - SPP 10 - 25; DDT - 100;
- ZVI-150 - SPP 16 - 35; DDT - 150.
At right choice screw terminal you can create a really reliable connection that will ensure uninterrupted operation of the power grid.
Connect wires of different sections with bolts
Another way to connect wires of different sections to each other is to create a contact using bolts, washers and nuts. According to professional electricians, such a connection is the most durable and strong. The process itself is not too complicated, it takes a minimum of time. The procedure goes as follows:
- the copper conductors of the wire are carefully stripped (the length of the stripped section of the conductor depends on the diameter of the bolt);
- the stripped core is bent in the form of a loop;
- the loop is put on the bolt;
- an intermediate washer is installed on top;
- then a loop of wire of a different section is put on and fixed with an intermediate washer.
This continues until all the wires are connected to each other. After putting on the last loop and the last washer, the structure is firmly tightened with a nut.
Use of copper lugs to contact connections
Also, a very simple way to create a reliable connection is to use copper tips. They are recommended to be used for contacting wires of large diameter. Before proceeding with the procedure, it is necessary to prepare not only the tips themselves, but also special equipment - crimping pliers or a hydraulic press.
With all the obvious advantages, this type of connection has one (but significant) drawback - rather solid dimensions, due to which the resulting structure may not fit in every junction box. Nevertheless, experts actively use this method.
The process of creating a contact is as follows:
- wires of different sections are carefully straightened;
- the veins of each of them are cleaned by about two to three centimeters;
- a tip is put on each stripped core and clamped with hydraulic press or crimping pliers;
- bolts are then put on, and the wires are connected with a nut.
After all the work has been done, it is necessary to carefully isolate the junction so that no dangerous situations arise during operation.
Self-wiring and creating contacts using terminals
Universal clamp terminals appeared on the market relatively recently, but almost immediately they began to be in serious demand not only among specialists, but also among potential customers who prefer all electric installation work do it yourself at home.
With self-clamping terminals, you can create strong and reliable contacts between several wires ( three or more). The main advantage of such terminal blocks is their almost limitless functionality - they can be used to connect wires whose sizes vary significantly.
The design of the terminals provides for the presence of holes into which pre-stripped conductors are inserted. For example, a wire with a cross section of 1.5 mm can be inserted into one hole, a wire with a diameter of 4 mm into another, a wire with a diameter of 4 mm into the third, and so on. And after their connection, the contact will be quite strong and reliable.
There are several more ways how to connect three or more wires of different diameters, but they are used quite rarely due to the complexity and length of the process itself. If you want to use one of them - consult first with a specialist who is competent in this particular area.