Electricity is not an area where you need to save money. It is advisable to do everything carefully, to select high-quality materials, to approach the choice of sizes / diameters / ratings carefully. To begin with, even connecting the conductors must be correct. And choosing the ways of connecting wires is not nearly as easy as it seems.
There are about a dozen ways to connect wires. In general, they can be divided into two groups: those that require special equipment or specific skills and those that any home craftsman can successfully use - they do not require any special skills.
The first group includes:
- Soldering. When connecting wires of small diameter in the amount of 2-3 pieces, it is a very reliable method. True, it requires a soldering iron and some skills in using it.
- Welding. We need a welding machine and special electrodes. But the contact turns out to be reliable - the conductors are fused into a monolith.
- Crimping with sleeves. We need sleeves and special pliers. Liners are selected according to certain rules that you need to know. The connection is reliable, but you will have to cut it to reseal it.
All these methods of connecting wires are performed mainly by specialists. If you have the skills to handle a soldering iron or a welding machine, after practicing on unnecessary trimmings, you can do them yourself.
Some ways of connecting wires are more popular, others less
Wiring methods that do not require any specific skills are becoming more and more popular. Their advantage is quick installation, reliable connection. Disadvantage - "connectors" are needed - terminal blocks, clamps, bolts. Some of them cost quite decent money (Wago terminal blocks, for example), although there are inexpensive options - screw terminal blocks.
So here are the ways to connect wires, which are simple to perform:
There are two opposing opinions among professionals. Some believe that new ways of connecting wires - clamps - are the best way out, since they speed up installation without compromising the quality of the connection. Others say that someday the springs will weaken and the contact will deteriorate. In this matter, the choice is yours.
Technical nuances of different types of wire connections
All the types of wire connections described above are used when laying electrical wiring, but a specific type is selected based on several characteristics:
Consider each connection method, the technology for its implementation and the feasibility of using it in various situations.
Soldering electrical wires
One of the oldest and most widespread types of compounds. To work, you will need rosin, solder and a soldering iron. The soldering process is as follows:
Actually, this is where the soldering of the electrical wires is completed. Not the most difficult process, but it requires certain skills. The main thing is to warm up the junction enough so that the solder flows between all the wires. In this case, it is impossible to overheat, otherwise the insulation will melt. This is the art - not to burn the insulation, but to provide a reliable contact.
When can soldering be used? This method of connecting wires works well in low-current electrics. When connecting wires in a junction box, it is no longer very convenient. Especially if there are a lot of wires and / or they are of large diameter. Soldering such a twist is not a task for beginners. In addition, when trying to lay the joint in the junction box, the soldering begins to deteriorate. Up to the point that some wires fall off. In general, the method is good for connecting small diameter conductors.
Welding conductors in electrical connections
One of the most reliable ways to connect wires is welding. During this process, the metal of the individual conductors is brought to the melting point, mixed, and after cooling it is a monolith. This method works very well on large diameters or with a large number of conductors to be connected. It is distinguished not only by excellent contact, which does not weaken over time and does not change its characteristics. It is also mechanically very strong - the fused part does not allow the joint to fall apart even under heavy loads.
Drop at the end of the twist - molten aluminum
There are also disadvantages. The first is precisely that the conductors are fused, that is, the connection is completely one-piece. If you need to repack it, you have to remove the fused part and start everything anew. To be able to do this, you always need to leave a small reserve along the length of the wires. The second drawback is that you need a welding machine, handling skills, special electrodes for welding aluminum or copper. The main task in this case is not to burn off the insulation, but to melt the conductors. So that this can be done, they are stripped of insulation by about 10 cm, tightly twisted into a bundle, and then welded at the very end.
Another disadvantage of welding wires is a laborious process, which also requires jewelry precision in handling the welding machine. Due to the combination of these qualities, many professional electricians do not like this method. If you pull the wiring "for yourself" and know how to handle the equipment, you can spend a certain amount of time. Just pre-practice on scraps, select the amperage and welding time. Only after a few times you get everything perfect, you can start welding wires "in real life".
Crimping
Another method that requires special equipment is crimping the wires with sleeves. There are copper and aluminum sleeves of different diameters. The material is selected depending on the material of the conductor, and the size is selected according to the diameter and number of wires in a particular connection. They should fill almost all the space inside the sleeve, but at the same time there should be free space. The quality of the contact depends on the correct choice of the sleeve size. This is the main difficulty of this method of connecting wires: the sleeve should not be too large or too small.
The technology of work is as follows:
- The conductors are stripped from insulation (the length of the stripped section is slightly more than the length of the sleeve).
- Each conductor is cleaned to a pure metal (remove oxides with fine-grain emery paper).
- The wires are twisted, inserted into the sleeve.
- Crimped with special pliers.
It seems that it is not difficult, but it is in the selection of the liner and the presence of ticks that the whole difficulty is. You can, of course, try to squeeze with pliers or pliers. But it is impossible to guarantee normal contact in this case.
Twisting
In the first section of the article, we deliberately omitted the twisting of wires. According to the current standard, it cannot be used because it does not provide proper contact and reliability of the connection. This method can replace any other way of connecting wires.
Yes, they did the wiring on twists 20-30 years ago and everything worked fine. But what were the loads on the networks then, and what are now ... Today, the amount of equipment in an ordinary apartment or private house has increased significantly and most of the equipment is demanding on power supply. Some types will simply not work at reduced voltage.
Why is twisting so bad? Wires twisted into a bundle do not make good contact. At first, everything is fine, but over time, the metal becomes covered with an oxide film, which significantly worsens the contact. With insufficient contact, the junction begins to heat up, an increase in temperature causes a more active formation of an oxide film, which further worsens the contact. At some point, the twist heats up very much, which can lead to a fire. It is for this reason that it is better to choose any other method. There are some that are even faster and easier to do, but which are more reliable.
Isolation of connections
All the above-described methods of connecting wires - welding, soldering, crimping with a sleeve - provide for their insulation, since bare conductive conductors must be protected. For these purposes, electrical tape or heat shrink tubes are used.
Everyone probably knows how to use electrical tape, but we will tell you a little about heat shrink tubes. This is a hollow polymer tube, which, when the temperature rises, significantly reduces its diameter (by 2-6 times, depending on the type). The size is selected so that the pre-shrinkage volume is larger than the diameter of the insulated wires, and the post-shrinkage volume is smaller. In this case, a tight adhesion of the polymer is ensured, which guarantees a good degree of insulation.
Heat shrink tubing for insulating conductors can be of different diameters and colors
In addition to the size, heat shrink tubes are selected for special characteristics. They are:
- heat resistant;
- light stabilized (for outdoor use);
- oil and petrol resistant;
- resistant to chemicals.
The cost of heat shrinkable tubes is not very high - from $ 0.5 to $ 0.75 per 1 meter. Their length should be slightly longer than the length of the bare conductors - so that one edge of the tube is pulled on the insulation of the conductors by about 0.5 cm, and the other sticks out by 0.5-1 cm. After the tube is stretched, take a heat source (you can use a lighter) and heat the tube. Heating temperature can be different - from 60 ° C to + 120 ° C. After the connection is covered, heating is stopped, after which the polymer cools quickly.
It takes little time to insulate the wires with a heat-shrinkable tube - it counts in seconds - and the quality of the insulation is high. Sometimes, for greater reliability, they can use two tubes - a slightly smaller and slightly larger diameter. In this case, first put on and warm up one tube, then the second. Such connections can be operated even in water.
Terminal blocks
This method is also preferred by electricians, but it can be easily used by a person who can hold a regular screwdriver in his hands. This is one of the first ways to connect electrical wires without soldering. Today, on almost every electrical appliance, you can see a variant of this connection - this is the output block to which the power cord is connected.
Terminal blocks are a contact plate that is sealed in a plastic (polymer) or carbolite housing. They cost very little, they can be found in almost any store that sells electrical goods.
Terminal blocks - convenient, inexpensive, allow you to connect copper and aluminum wires, conductors of different diameters, single- and stranded
The connection takes place literally in seconds. The insulation is removed from the conductor (by about 0.5-0.7 cm), the oxide film is removed. Two conductors are inserted into the socket - one opposite the other - and fixed with bolts. These bolts press the metal against the contact plate, providing the connection.
The advantage of this connection method: you can connect wires of different cross-sections, single-core with multi-core. The disadvantage is that only a pair of wires are connected. To connect three or more, it is necessary to install jumpers.
PPE caps
Another way to connect wires that does not require special skills is to install PPE caps. They represent a plastic cone-shaped body, inside which a spring is sealed. They come in different sizes - from 0 to 5. You can connect wires of different diameters - on each package the minimum and maximum and minimum total cross-section of the wires to be connected is written. In addition, there are casings simply in the form of a cone, there are lugs with stops that facilitate their installation. When choosing, pay attention to the quality of the plastic - it should not bend.
It is very simple to connect wires with PPE: you strip the insulation, collect the wires in a bundle, insert them inside the cap and start twisting. A spring inside the cap grips the conductors, helping to twist them. The result is a twist that is wrapped around the outside with a spring wire. That is, the contact is very high quality and good. This method of connecting wires with PPE caps has been used for a long time in Europe and America, it came to us about 10 years ago.
If you need ways to connect wires without welding - consider PPE
There is another way: first, the wires are twisted, then caps are put on them. This method was invented by a Russian company that produces these connectors for wires - KZT. But this technique takes more time, and the quality of the connection is no different.
There is one more point: how long to strip the wire from the insulation. Manufacturers in this regard give clear instructions - for each size its own length of bare conductors. It is designed so that all bare conductors are inside the enclosure. If you do this, the connection does not require additional isolation, which greatly speeds up the process. In addition, the expanded lower part does not interfere with heat dissipation and such a connection heats up less.
Practicing electricians advise stripping the wires by 5-10 cm, and insulating the remaining twist without insulation. This is argued by the fact that the contact area with this option is larger. It is so, but this option heats up more. And the standard solution has reliability. There are no contact problems (with normal quality of PPE).
Clamps Wago
The most heated debate flared up specifically about Vago. Some people like this product unconditionally, others don't like it. Moreover, no less categorically. Opponents of Wago don't like the fact that the contact is spring-based. They say that she may weaken. This will lead to poor contact and overheating. And they bring a photo with melted clamps. Proponents of this method conduct tests and comparisons, they say that a properly selected branded clamp serves for many years without signs of deterioration in contact. And the manufacturers say that, subject to the technology, Wago terminal blocks can be operated for 25-35 years. It is important to choose the right type and parameters and not buy a fake (there are a lot of them).
There are two types of Vago clamps. The first series is slightly less expensive, called Wago. These clamps are suitable for connecting solid and stranded wires with a cross section of 0.5-4 mm2. For conductors with smaller or larger cross-sections, there is another series - Cage Clamp. It has a very wide range of use - 0.08-35 mm2, but also a great cost. In any case, contact is provided by a good copper contact plate. The special shape of the plate allows for reliable contact.
Detachable
In addition, Vago spring-loaded clamps are split (222 series) and one-piece (773 and 273 series). Detachable ones are convenient to install in those places where network configuration changes are possible. For example, in junction boxes. They have levers with which the wires are clamped or released. Wago plug-in terminal blocks can connect from 2 to 5 conductors. Moreover, they can be of different sections, type (single-core and multi-core). The order of connecting the wires is as follows:
We repeat the same operation with other (other) wires. All this takes a matter of seconds. Very fast and convenient. Not surprisingly, many professional electricians have forgotten other ways to connect wires.
One-piece
One-piece series differ in structure: there is a clamp body and a cap. The cap can be made of transparent polymer (773 series) or opaque plastic (223). There are holes in the case, into which wires stripped from insulation are inserted.
To ensure normal contact, you just need to properly remove the insulation - exactly by 12-13 mm. These are the requirements of the manufacturer. After the conductor is inserted, its bare part should be in the terminal block, and the insulation should rest against the case. Under these conditions, the contact will be reliable.
Bolted connection
Another type of connection of electrical wires with a solid experience is bolted. It is called so because a bolt, nut and several washers are used to connect the wires. The contact due to the use of washers is quite good, but the whole structure takes up a lot of space and is inconvenient to lay. It is used mainly if it is necessary to connect conductors made of different metals - aluminum and copper.
The order of assembly of the connection is as follows:
- We clean the wires from insulation.
- From the stripped part, we form a loop, the diameter of which is equal to the diameter of the bolt.
- We put on the bolt in the following sequence
- washer (it rests against the head of the bolt);
- one of the conductors;
- another washer;
- second conductor;
- the third washer;
- We tighten everything with a nut.
So you can connect not only two, but also three or more wires. Please note that tightening the nut should not only be done by hand. It is necessary to use wrenches, make a solid effort.
The best ways to connect wires for different occasions
Since different wires can be connected, they can be operated in different conditions, the optimal method must be chosen taking into account all these nuances. Here are the most common situations:
These are the most common custom connections.
Ways to connect wires
Contact connections of conductors are a very important element of the electrical circuit, therefore, when performing electrical work, you must always remember that the reliability of any electrical system is largely determined by the quality of electrical connections.
Certain technical requirements are imposed on all contact connections. But first of all, these connections must be resistant to mechanical factors, be reliable and safe.
With a small area of contact in the contact zone, a rather significant resistance can arise for the passage of current. The resistance at the point where the current passes from one contact surface to another is called the contact resistance, which is always greater than the resistance of a solid conductor of the same size and shape. During operation, the properties of a contact connection under the influence of various factors of an external and internal nature can deteriorate so much that an increase in its transition resistance can cause overheating of the wires and create an emergency. The transient contact resistance largely depends on the temperature, with an increase in which (as a result of the passage of current) an increase in the transient resistance of the contact occurs. Contact heating is of particular importance in connection with its effect on the oxidation process of contact surfaces. In this case, the oxidation of the contact surface is the more intense, the higher the contact temperature. The appearance of an oxide film, in turn, causes a very strong increase in the transfer resistance.
It is an element of an electrical circuit where two or more separate conductors are connected electrically and mechanically. At the point of contact of the conductors, an electrical contact is formed - a conductive connection through which current flows from one part to another.
Simple superposition or slight twisting of the contact surfaces of the conductors to be connected does not provide good contact, since due to microroughnesses, actual contact does not occur over the entire surface of the conductors, but only at a few points, which leads to a significant increase in the contact resistance.
At the point of contact of two conductors, there is always a transient resistance of the electrical contact, the value of which depends on the physical properties of the contacting materials, their state, the compressive force at the point of contact, temperature and the actual area of contact.
In terms of electrical contact reliability aluminum wire does not compete with copper... After a few seconds of exposure to air, the pre-cleaned aluminum surface is covered with a thin hard and refractory oxide film with high electrical resistance, which leads to an increased contact resistance and strong heating of the contact zone, as a result of which the electrical resistance increases even more. Another feature of aluminum is its low yield strength. A tightly tightened connection of aluminum wires weakens over time, which leads to a decrease in contact reliability. In addition, aluminum has the worst conductivity. That is why the use of aluminum wires in household electrical systems is not only inconvenient, but also dangerous.
Copper oxidizes in air at normal residential temperatures (about 20 ° C). The resulting oxide film does not have great strength and is easily destroyed by compression. Copper oxidation is particularly intense at temperatures above 70 ° C. An oxide film on a copper surface itself has little resistance and has little effect on the value of the contact resistance.
The state of the contact surfaces has a decisive influence on the growth of the contact resistance. To obtain a stable and durable contact connection, a high-quality stripping and surface treatment of the connected conductors must be performed. The insulation from the cores is removed to the required length with a specialized tool or knife. Then the bare parts of the veins are cleaned with emery cloth and treated with acetone or white spirit. The length of the groove depends on the characteristics of the particular method of connection, branching or termination.
The transient contact resistance decreases to a large extent with an increase in the compressive force of the two conductors, since the actual contact area depends on it. Thus, in order to reduce the transient resistance in the connection of two conductors, it is necessary to ensure their sufficient compression, but without destructive plastic deformations.
There are several ways to install the electrical connection. The highest quality of them will always be the one that provides, under specific conditions, the lowest value of the transient contact resistance for as long as possible.
According to the "Rules for Electrical Installations" (clause 2.1.21), connection, branching and termination of conductors of wires and cables must be carried out by welding, soldering, crimping or compressing (screw, bolt, etc.) in accordance with the current instructions. In such connections, it is always possible to achieve a consistently low contact resistance. In this case, it is necessary to connect the wires in compliance with the technology and using the appropriate materials and tools.
This is an important and responsible operation. It can be performed in various ways: using terminal blocks, by soldering and welding, crimping, and often by ordinary twisting. All of these methods have certain advantages and disadvantages. It is necessary to choose a connection method before starting installation, as this also involves the selection of appropriate materials, tools and equipment.
At connecting wires the same color of neutral, phase and grounding wires should be observed. Usually, the phase wire is brown or red, the neutral working wire is blue, the protective ground wire is yellow-green.
Very often, electricians have to connect a wire to an existing line. In other words, you need to create a branch of the wires. Such connections are made using special branch clamps, terminal blocks and piercing clamps.
When directly copper and aluminum form a galvanic pair, and an electrochemical process occurs at the point of contact, as a result of which aluminum is destroyed. Therefore, to connect copper and aluminum wires, you need to use special terminal or bolted connections.
Wires connected to various devices often require special ferrules to ensure reliable contact and reduce contact resistance. These lugs can be soldered or crimped to the wire.
There are many different types. For example, for copper stranded conductors, lugs are produced from a solid-drawn copper pipe, flattened and drilled for a bolt on one side.
Welding. Welding wire connection.
Gives a monolithic and reliable contact, so it is widely used in electrical work.
Welding is performed at the ends of pre-stripped and twisted conductors with a carbon electrode using welding machines with a power of about 500 W (for a cross-section of twists up to 25 mm2). The current on the welding machine is set from 60 to 120 A, depending on the section and the number of wires to be welded.
Due to the relatively low currents and low (compared to steel) melting temperature, the process occurs without a large blinding arc, without deep heating and metal splashing, which makes it possible to use protective goggles instead of a mask. At the same time, other security measures can be simplified. At the end of welding and cooling of the wire, the bare end is insulated with electrical tape or heat shrink tubing. After a short training, using welding, you can quickly and efficiently make the connections of electrical wires and cables in the power supply system.
When welding, the electrode is brought to the wire to be welded until it touches, then it is retracted a short distance (OD-1 mm). The resulting welding arc melts the twist of the wires to form a characteristic ball. The contact with the electrode should be brief to create the desired reflow zone without damaging the wire insulation. It is impossible to make a long arc length, since the welding place turns out to be porous due to oxidation in the air.
Currently, welding work on connecting electrical wires is convenient to perform with an inverter welding machine, since it has a small volume and weight, which allows an electrician to work on a stepladder, for example, under the ceiling, hanging the inverter welding machine on his shoulder. A copper-plated graphite electrode is used for welding electrical wires.
In a joint obtained by welding, an electric current flows through a monolithic metal of the same type. Of course, the resistance of such connections turns out to be record low. In addition, such a connection has excellent mechanical strength.
Of all the known methods of connecting wires, none of them can compare with welding in terms of durability and conductivity of the contact. Even soldering collapses over time, since a third, more fusible and loose metal (solder) is present in the joint, and at the interface of different materials there is always additional transition resistance and destructive chemical reactions are possible.
Soldering. Solder wire connection.
Soldering is a method of joining metals with the help of another, more low-melting metal. Compared to welding, brazing is simpler and more affordable. It does not require expensive equipment, is less fire hazardous, and skills to perform good quality soldering will require more modest ones than when making a welded joint. It should be noted that the metal surface in air usually quickly becomes covered with an oxide film, so it must be cleaned before soldering. But the cleaned surface can quickly oxidize again. To avoid this, chemicals are applied to the treated areas - fluxes that increase the fluidity of the molten solder. Thanks to this, the soldering is stronger.
Soldering is also the best way termination of copper stranded conductors into a ring - the soldered ring is evenly covered with solder. In this case, all wires must fully enter the monolithic part of the ring, and its diameter must correspond to the diameter of the screw clamp.
The process of soldering wires and cable cores consists in covering the heated ends of the connected cores with molten tin-lead solder, which provides mechanical strength and high electrical conductivity of the permanent connection after hardening. Soldering should be smooth, without pores, dirt, sagging, sharp bulges of solder, foreign inclusions.
For soldering copper conductors of small sections, use solder tubes filled with rosin, or a solution of rosin in alcohol, which is applied to the junction before soldering.
To create a high-quality soldered contact connection, the conductors of the wires (cables) must be carefully irradiated, and then twisted and crimped. The quality of the soldered contact largely depends on the correct twisting.
After soldering, the contact joint is protected with several layers of insulating tape or heat shrink tubing. Instead of insulating tape, the soldered contact joint can be protected with an insulating cap (PPE). Before that, it is desirable to cover the finished compound with a moisture-resistant varnish.
Parts and solder are heated with a special tool called a soldering iron. A prerequisite for creating a reliable connection by soldering is the same temperature of the surfaces to be soldered. Of great importance for the quality of soldering is the ratio of the temperature of the soldering iron tip and the melting temperature. Naturally, this can only be achieved with the right tool.
Soldering irons vary in design and power. To perform household electrical work, an ordinary 20-40 W electric rod soldering iron is quite enough. It is desirable that it be equipped with a temperature regulator (with a temperature sensor) or at least a power regulator.
Experienced electricians often use the original soldering method. A hole with a diameter of 6-7 mm and a depth of 25-30 mm is drilled in the working rod of a powerful soldering iron (at least 100 W) and filled with solder. In a heated state, such a soldering iron is a small tinning bath, which allows you to quickly and efficiently solder several multi-core connections. Before soldering, a small amount of rosin is thrown into the bath, which prevents the appearance of an oxide film on the surface of the conductor. The further soldering process consists in lowering the twisted joint into such an impromptu bath.
One of the common ways to create a contact is to use screw terminal blocks... In them, reliable contact is ensured by tightening the screw or bolt. In this case, it is recommended to connect no more than two conductors to each screw or bolt. When using stranded conductors in such connections, the ends of the wires require preliminary tinning or the use of special ferrules. The advantage of such connections is their reliability and collapsibility.
By designation, terminal blocks can be bushing and connecting.
Designed to connect wires to each other. They are usually used for switching wires in junction boxes and distribution boards.
Feed-through terminal blocks are used, as a rule, for connecting various devices to the network (chandeliers, lamps, etc.), as well as for splicing wires.
When connecting wires with stranded conductors using screw terminal blocks, their ends need to be pre-soldered or crimped with special ferrules.
When working with aluminum wires, the use of screw terminal blocks is not recommended, since aluminum conductors, when tightened with screws, are prone to plastic deformation, which leads to a decrease in the reliability of the connection.
Recently, a very popular device for connecting wires and cores of cables has become self-clamping terminal blocks type WAGO... They are designed to connect wires with a cross-section of up to 2.5 mm2 and are designed for an operating current of up to 24 A, which allows you to connect a load of up to 5 kW to the wires connected by them. In such terminal blocks, you can connect up to eight wires, which greatly speeds up the wiring in general. True, in comparison with twisting, they take up more space in unsoldered boxes, which is not always convenient.
The screwless terminal block is fundamentally different in that its installation does not require any tools and skills. A wire stripped to a certain length is inserted into its place with little effort and reliably pressed by a spring. The design of the screwless terminal connection was developed in the German company WAGO back in 1951. There are other manufacturers of this type of electrical products.
In spring-loaded self-clamping terminal blocks, as a rule, the effective contact surface area is too small. At high currents, this leads to heating and release of the springs, as a result of which there is a loss of their elasticity. Therefore, such devices should only be used on connections that are not subject to heavy loads.
WAGO produces terminal blocks both for installation on a DIN rail and for fastening with screws to a flat surface, but construction terminal blocks are used for installation as part of household wiring. These terminal blocks are available in three types: for junction boxes, for luminaire fittings and universal.
WAGO terminal blocks for junction boxes, it is possible to connect from one to eight conductors with a cross section of 1.0-2.5 mm2 or three conductors with a cross section of 2.5-4.0 mm2. And terminal blocks for luminaires connect 2-3 conductors with a cross section of 0.5-2.5 mm2.
The technology of connecting wires using self-clamping terminal blocks is very simple and does not require special tools and special skills.
There are also terminal blocks in which the conductor is fixed using a lever. Such devices allow you to achieve good clamping, reliable contact and, at the same time, are easily disassembled.
One of the most popular connecting products among electricians is. This clamp is a plastic housing with an anodized conical spring inside. To connect the wires, they are stripped to a length of about 10-15 mm and folded into a common bundle. After that, PPE is wound on it, rotating clockwise until it stops. In this case, the spring compresses the wires, creating the necessary contact. Of course, all this happens only when the PPE cap is selected correctly for its face value. With the help of such a clamp, it is possible to connect several single wires with a total area of 2.5-20 mm2. Naturally, the caps in these cases are of different standard sizes.
Depending on the size, PPEs have certain numbers and are selected according to the total cross-sectional area of the twisted conductors, which is always indicated on the package. When choosing PPE caps, one should be guided not only by their number, but also by the total cross-section of the wires for which they are designed. The color of the product has no practical meaning, but it can be used to mark phase and neutral conductors and grounding conductors.
PPE clamps significantly speed up the installation, and due to the insulated case, they do not require additional insulation. True, the quality of the connection is slightly lower than that of the screw terminal blocks. Therefore, other things being equal, preference should still be given to the latter.
Twisting. Twisted wire connection.
Twisting bare wires as a connection method is not included in the "Rules for Electrical Installations" (PUE). But despite this, many experienced electricians consider a correctly performed twisting as a completely reliable and high-quality connection, arguing that the transition resistance in it practically does not differ from the resistance in the whole conductor. Be that as it may, good twisting can be considered one of the stages of connecting wires by soldering, welding or PPE caps. Therefore, high-quality twisting is the key to the reliability of all electrical wiring.
If the wires are connected according to the principle of "how it happened", a large transition resistance can arise at the point of contact with all the negative consequences.
Depending on the type of connection, twisting can be performed in several ways, which, with a small transfer resistance, can provide a completely reliable connection.
First, the insulation is carefully removed without damaging the wire core. Sections of veins exposed to a length of at least 3-4 cm are treated with acetone or white spirit, cleaned with sandpaper to a metallic sheen and tightly twisted with pliers.
Crimping method widely used for making reliable connections in junction boxes. In this case, the ends of the wires are stripped, combined into appropriate bundles and pressed in. After crimping, the connection is protected with electrical tape or heat shrink tubing. It is one-piece and does not need maintenance.
Crimping is considered one of the most reliable ways to connect wires. Such connections are made using sleeves by continuous compression or local indentation with special tools (press tongs), into which replaceable dies and punches are inserted. In this case, the wall of the sleeve is pressed (or squeezed) into the cores of the cable with the formation of a reliable electrical contact. Crimping can be done by local indentation or solid crimping. Solid crimps are usually in the form of a hexagon.
It is recommended to treat copper wires with a thick grease containing technical petroleum jelly before crimping. This lubrication reduces friction and reduces the risk of core damage. A non-conductive lubricant does not increase the transition resistance of the connection, since if the technology is observed, the lubricant is completely displaced from the contact point, remaining only in the voids.
For crimping, manual pressing tongs are most often used. In the most common case, the working bodies of these tools are matrices and punches. In the general case, the punch is a movable element that produces local indentation on the sleeve, and the matrix is a curly fixed bracket that perceives the pressure of the sleeve. Dies and punches can be replaceable or adjustable (designed for different sections).
When installing ordinary household wiring, as a rule, small crimping pliers with curly jaws are used.
As a sleeve for crimping, you can, of course, use any copper tube, but it is better to use special sleeves made of electrical copper, the length of which corresponds to the conditions for the reliability of the connection.
When crimping, the wires can be inserted into the sleeve both from opposite sides until they touch each other strictly in the middle, and from one side. But in any case, the total cross-section of the wires must correspond to the inner diameter of the sleeve.
In the article we will tell you how to connect the power cable to the shield / battery / amplifier / outlet, etc., consider the diagrams and instructions. Industrial enterprises produce a large number of varieties of power cables and circuit elements through which they are connected:
- Distribution boards;
- Sockets, single-phase, three-phase;
- Connectors of various designs for household and industrial equipment;
- Batteries in DC networks and others.
In all cases, there are features of installation work that are recommended to be observed to ensure high-quality contacts. Reliable connection of the cable with other elements of the network ensures long-term and trouble-free operation of the power line itself, all its elements and equipment connected to it.
Connecting the power cable to the switchboard
There are many factors to consider before laying the cable to the switchboard:
- Location of the distribution board;
- Outdoors, dry or humid;
- The design of the board, the location of the busbars and cable fastening elements;
- Locations of inlet openings on the switchgear housing for cables and other points.
First of all, it is planned from which side the cables will come to the switchboard. In the production of plastic and metal cases of the distribution board, the contours of technological holes are stamped for entering cables from several sides. This punching allows you to quickly open the hole from the desired side. Please note that according to the requirements of the PUE clauses 1.1.7 and 1.1.8, outdoors in the open air or in rooms with high humidity, cables are wound only from the bottom side of the distribution board. This reduces the likelihood of moisture getting into the outer insulation shell and into the cabinet.
Cable stripping and connection
Almost all lead-in cables for high current loads have at least double insulation, on each core and outer sheath. Therefore, regardless of what brand of cable for installation, the following operations are performed:
-
The outer insulating layer is removed by a mounting knife 150 - 250 mm from the end of the cable;
- Separate the cores, it is recommended to immediately mark the cable and each wire. There are many ways of marking, one of the simplest is to put cambric on the wires with the corresponding inscriptions. A sticker is glued onto the general shell with transparent tape, it indicates where the cable comes from and where, the brand of the cable, the number and cross-section of the cores, and the length. Wires of the same color can be marked with colored cambric or electrical tape, for professional electricians this marking is understandable. Blue, black means neutral wire, red, brown or white phase, yellow-green ground.
- The cable is brought into the distribution board with a margin of up to 0.5m for cutting and in case of possible changes in the connection diagram. To do this, near the cabinet, it is folded into a loop, if space permits, the loop can be placed inside the cabinet.
- In modern distribution boards, holders or crossbars are made for laying cables in vertical or horizontal positions. The cable is fixed to the fastening elements with plastic clamps with a lock.
- Inside the cabinet, the cable is mounted in the direction of the busbars or to the contacts of the input circuit breaker.
- The ends of the wires are stripped from insulation by 1-1.5 cm, tubular tips of the corresponding diameter are put on them and crimped with a special press.
- The contact tips are flattened on one side and have holes for bolts with which the contact plane is pressed against the bus or terminal of the circuit breaker.
- In some models of automatic circuit breakers, the tips are not required, the bare ends of the wires are inserted into the contact group and clamped with bolts.
For reliable contact, it is very important that the planes of the lugs are adjacent to the busbars as much as possible. Under these conditions, good current flow will be ensured. Wires with a cross section of up to 10 mm 2 in the distribution board and the ASU can be connected to special blocks with clamping bolts, where terminals are not required.
When connecting the cable to the three-phase line shields, the requirements for laying the cable to the cabinet and inside remain the same, except for the marking, the neutral wire and grounding are indicated by the letter "N" in blue, blue and "PEN" - yellow-green. The phases are designated by the letters "A" "B" and "C". All cables are labeled on both sides and the wire designation on both ends must match. Read also the article: → "".
Connecting Power Cables to Outlets
It is recommended to use a VVG cable for laying wiring in the outlet group of the premises. In wooden structures, VVGng is laid, which is insulated from a non-combustible material, there is an imported analogue of this NYM wire, but it is significantly more expensive.
Council number 1. It is not recommended to install wires of the PUNP brand, they are convenient for laying, but very rarely correspond to the declared characteristics. This is due to unscrupulous manufacturers, 80% of the products on the market are defective, the percentage of copper in the alloy is underestimated, the insulation layer and the cross-section of the wires are thinner, and many other inconsistencies. These shortcomings lead to emergency situations, the cable does not withstand the calculated current loads, the wires burn out.
When planning, the maximum power of electrical appliances connected to the outlet group is taken into account, the choice of wire cross-section depends on this. Statistics and practical experience show that for an apartment or a private house, wires with a cross section of 4 mm 2 are laid between junction boxes in socket groups. From a junction box to a 2.5 mm 2 socket, provided that ordinary household appliances of low power, a TV, an iron, a refrigerator, handheld power tools and other equipment are turned on.
In junction boxes and socket boxes, the cable is wound up to 15 - 20 cm, the outer sheath is removed up to 10 cm, the insulation from the wires is 5 cm in the junction box, in the socket boxes up to 1 cm.Bare ends in the junction box for connection to the outlet are twisted together with two pliers ... Both wires are clamped together near the end of the insulation, and near the bare ends. The former remain stationary; the latter, rotational movements are made to twist a pair or more wires.
At the same time, one must have a sense of proportion, twist tightly, but not overtighten until the twist breaks. In the classic version, the ends of the twists in the junction boxes are welded with a welding machine, a DC step-down transformer, with a graphite electrode. But most often installers do not adhere to these technologies, the twists are simply insulated with electrical tape or plastic caps. Read also the article: → "".
From the switchboard to the outlet, the cable wires are connected in accordance with the requirements of the PUE, by color. A red or brown wire goes from the phase contact, they also connect in the junction box and go down to the outlet. Neutral wires with blue insulation and yellow - green are connected throughout the network, starting from the ground bus in the distribution board.
The socket is connected to the wires coming out of the socket, the phase and neutral conductors are attached to the contacts into which the plug from electrical appliances is inserted. The grounding wire to the contact with the grounding designation, the methods of fixing the wires to the contacts may be different, it depends on the type of sockets.
There are contact groups with screw or spring terminals. After connecting the wires and the socket housing are packed into a socket box, spacer screws are screwed in, everything is closed with a front decorative cover.
Features of connecting power cables to a battery or other DC sources
In industrial facilities and in household activities, equipment that operates from direct current sources is often used. The most common are rechargeable batteries:
- They are used for the starter, engine start and power supply of other automotive equipment;
- Connect to chargers;
- To inverters (converters) of direct current voltage into alternating current 12 / 220V; 24 / 220V and others;
- Batteries are actively used as backup power supplies in the absence of voltage in the industrial network and other options.
In all these cases, in order to ensure long-term and trouble-free operation of the equipment, it is very important to correctly connect the cable:
- The most important requirement for connecting the cable or individual wires to the battery is to observe the polarity. Otherwise, the electronic components of the equipment may burn out and the battery will be discharged. The wire connected to the positive terminal is usually installed with red insulation, blue or black wires are connected to the negative.
On the battery case, next to the contacts are marked "+" and "-". The same designations are placed on the connected equipment and on the ends of the wires on both sides;
- It is imperative to take into account the cross-section of the wires, it must correspond to the currents of the connected load, this can be correctly determined using pre-calculated tables.
- The reliability of the connected contacts is of great importance; for this, special terminals, lead or brass, are made for acid batteries. The design of the terminals provides for the installation locations of the wires and contacts of the battery; the clamp is carried out with bolts. For lithium ion batteries, the contact connections may be of a different design.
Before connecting all the cells to the battery contacts, it is very important to ensure that they are clean, especially on acid batteries that have been in operation. Oxide builds up on lead and brass elements, which prevents the flow of current. To remove it, metal brushes are used, you can take a hard toothbrush to treat the contacts with an alkaline solution that neutralizes the acidic components. After cleaning, you can put the terminals with wires on the battery contacts and clamp them with bolts.
Connecting the amplifier (subwoofer) to the car battery
Some lovers of loud music install power amplifiers to car stereos and players. The problem with this circuit is the high power consumption, the car battery is not always sufficient to provide power for automotive equipment and music equipment. In this case, a separate additional battery is used. In any case, it is important to correctly calculate all the necessary parameters and correctly perform the installation:
- First of all, they are determined with the place of installation of the amplifier, usually this is done in the rear of the car in the trunk;
- The distance for laying the power cables to the battery is calculated;
- The brand of the cable is selected and the cross-section of the wires is calculated based on the power of the amplifier.
For car radio tape recorders, amplifiers with a power of 50 - 80 W are used, the calculations are carried out according to the formula:
I = P / U The flowing current "I" flowing through the wires is equal to the ratio of the power "P" of the amplifier to the voltage of the car battery "U". If your 4-channel amplifier is 60W x 4 = 240W, total power consumption. The current in the power supply circuit of the subwoofer will be 240W / 12V = 20A. For a power reserve, add about 20% and, according to the table, select the required wire cross-section based on a current of 24A. With constant current, the power significantly depends on the length of the wire from the power source to the consumer.
Practice shows that a cross section of 1.5 - 2.5 mm is quite enough to power the amplifier from an on-board battery with a voltage of 12V.
Flexible, stranded wires with a reliable insulating layer are selected. Red is connected to the positive terminal of the battery and the corresponding terminal on the amplifier, through a fuse of the calculated current value.
From the trunk to the engine compartment, where there is a 4-5m battery, the cable is laid in a corrugated hose. In the partition of the front panel, the corrugation is laid through the technological holes with rubber glands to prevent chafing of the insulation and short circuits under vibration conditions. The negative wire is attached between the negative terminal of the amplifier and the nearest bolt on the car body in the luggage compartment.
Council number 2. It is not recommended to run the control and speaker wires in parallel, next to the power wires. This will cause noise and distortion in audio playback.
To connect on-board equipment to the battery, cables with flexible stranded wires are usually used. For the installation of outdoor lighting lines, hidden wiring of socket groups, brands with monolithic rigid wires, not of large cross-section, are laid. To connect the distribution board from substations and overhead lines, cables of large cross-section 10, 16 mm 2 and more with monolithic conductors and stranded wires made of aluminum or copper alloy are used.
Some brands of power cables
Manufacturers make a large number of brands of wires with stranded wires, but only a few types are in great demand for connecting household, industrial equipment and individual structures. Read also the article: → "".
VVG. A power cable with stranded copper wires, hermetically sealed and durable PVC insulation, is laid to connect the distribution board through the air on traces, along walls, underground and cable ducts in various structures. It is very flexible and suitable for trails where there are a lot of turns and bends.
AVVG. This is practically the same cable as VVG, but the letter "A" means that the conductors are made of aluminum wire, without the letter, by default it means that the wires are copper.
Two letters "B" mean that each core and outer sheath is covered with a vinyl insulation layer, "G" - bare cable does not have additional armored protection.
Specifications:
AVK. The cable has a coaxial structure, in the center there is a monolithic aluminum core, then an insulating vinyl layer, which is shielded with thin aluminum wires arranged in a row around the diameter along the entire length. The outer shell is made of durable sealed plastic.
The cable is very practical, it can be laid from overhead lines with voltage up to 380V, underground from substations to switchboards of buildings. One of its main advantages is the exclusion of the possibility of unauthorized connection on uncontrolled sections of the route.
SIP-4. A feature of this cable is its self-supporting structure, which allows the cable to be placed on overhead lines without a cable suspension.
This quality makes it versatile, it can be laid along the walls of structures, underground and cable channels, in rooms with high humidity. It has reliable PVC sealed insulation on each multi-core wire.
The main parameters of SIP-4:
| Number and cross-section of veins, mm 2 | outerØ mm | Weight of self-supporting insulated wire cable, kg / km |
| 1x16 | 7.5 | 70 |
| 1x25 | 8.5 | 100 |
| 2x16 | 15.5 | 140 |
| 2x25 | 17.5 | 200 |
| 3x16 | 16.5 | 205 |
| 3x25 | 18.5 | 290 |
| 4x16 | 18.5 | 280 |
| 4x25 | 21.0 | 395 |
For the supply from the overhead line to the distribution board of a residential building, 3x16 or 4x16 cables are usually used; this number of wires in the cable and the cross-section is quite enough for the power consumed in domestic conditions.
AVBbShv / VBbShv. The design feature of this cable is the presence of an armored layer, two steel strips are wound on the surface of the cable so that the upper one overlaps the gaps between the turns of the lower ribbon. The cable is completely armored, in addition, PVC insulation on each core and a common sheath.
Decoding of marking:
- A - aluminum conductors can be monolithic or twisted from separate wires, the absence of this letter by default implies a copper alloy of wires.
- B - vinyl insulation of wires;
- BB - armored steel belts;
- Shv - PVC hose as outer insulating sheath.
- Shv ng - may mean that the insulation is made of non-combustible materials.
In the structure of the cable, there can be from 1 to 5 cores of the same or different cross-section, usually the ground wire is yellow-green or neutral blue in color, made of a smaller diameter. To connect private houses, do not use cables with a wire cross-section of more than 16 mm 2. In industrial facilities, the cross-section can reach 300 mm 2 and more.
Specifications:
| Number of cores, mm 2 | Outer cable diameter, mm | Weight of 1 km of cable, kg | ||||
| AVBbShv | AVBbShv ng | |||||
| ~ 660 V | ~ 1000 V | ~ 660 V | ~ 1000 V | ~ 660 V | ~ 1000 V | |
| 3x4 | 15.5 | 17 | 380 | 435 | 395 | 450 |
| 3x6 | 16.5 | 18 | 435 | 495 | 450 | 510 |
| 3x10 | 19.0 | 19.5 | 575 | 595 | 595 | 615 |
| 3x16 | 21.5 | 22.0 | 720 | 744 | 745 | 770 |
| 3x25 | 25 | 25.5 | 955 | 980 | 985 | 1010 |
| 3x35 | 27.0 | 27.5 | 1135 | 1160 | 1170 | 1200 |
| 3x50 | 30.5 | 31.0 | 1445 | 1480 | 1490 | 1525 |
| 3x4 + 1x2.5 | 16.5 | — | 420 | — | 435 | — |
| 3x6 + 1x2.5 | 17.5 | — | 490 | — | 505 | — |
| 3x6 + 1x4 | 17.5 | 19.0 | 370 | 555 | 390 | 570 |
| 3x10 + 1x4 | 30 | — | 675 | — | 695 | |
A cable with armored protection is allowed to be laid in an environment with high humidity and underground, but this does not exclude the possibility of using it in other more favorable conditions.
Errors when choosing a cable and connecting
- Most often, gross errors during installation work are made when choosing a cable. Be sure to take into account the conditions in which it will be used and calculate the required section. If you install an armored cable of a large cross-section where VVG 3x6 is enough, there will be extra financial costs and problems in installation work. You will not get advantages during operation and savings.
- When connecting to the PDS busbars, do not install copper lugs on aluminum wires and vice versa. Heterogeneous metals have different resistances, this leads to high current losses and heating of the wires at the connection points.
- Try to keep the busbars in the PDS and the wires of the same metal, copper or aluminum. If they are different, use a combination adapter to connect aluminum to copper.
- After connecting the cable to the busbars or circuit breakers, connect the maximum possible load for a couple of hours. Then de-energize the PDP and stretch all the bolted connections on the contacts. This is especially important at industrial facilities, where there are large current loads in the network for a long time, the contacts are inspected and pulled out once a week. If the clamp is insufficient, the contacts will burn out.
- It is not recommended to loop the end of the bare wire around the clamping bolt with washer for contact with the busbar. Such a connection has a smaller contact area than the tip, the current loss will be greater.
Frequently asked v polls
Question number 1. Can aluminum wires from AVVG be connected to the battery?
No, especially to the acid one, there will be large current losses due to the difference in resistance at the junctions. Lead contacts, terminals can be copper, and aluminum wires.
Question number 2. In a car, an amplifier with a 220V power supply can be connected via a 12 / 220V inverter?
Practically possible, but it is better to use 12V equipment in order to save energy and safety.
Question number 3. What is the best wire to connect welding machines?
It is possible with stranded VVG, but better with rubber insulation KG, the cross section is calculated based on the power of the device.
Question number 4. From power lines to distribution boards at home, which cable is better to use?
Best of all, self-supporting insulated wire brands with a cross section of 10 - 16 mm2, this is quite enough, less installation costs, no additional cable is required at a distance of up to 20 m.
Question number 5. The cable runs over a concrete fence, is constantly connected, electricity is stolen, insulation is spoiled, how to avoid it?
You can, of course, bury the cable, or run it over an overhead line, if it is expensive or impossible, the best option is to install an AVK brand cable. Its design excludes the possibility of unauthorized connection in uncontrolled areas.
First of all, you should 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 2.5mm2 in a compact junction box with terminal blocks or clamps. But if we are talking about a strobe or a cable channel, then the sleeves come out on top here.
Let's consider three of the simplest and at the same time reliable types of connections.
Let's start with a PPE type connection. It stands for:
- WITH unifying
- AND isolating
- Z press
It looks like a simple cap. It comes in different colors. 
Moreover, each color means belonging to specific sections of the veins.
The cores are inserted into this cap and twisted together. 
How to do it right, first twist the veins and then put on a cap or twist them directly with PPE itself, is discussed in detail in the article "." 
As a result, thanks to PPE, you get a good old twist, only immediately protected and isolated.
On top of that, with a spring-loaded contact that prevents it from loosening. 
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 type is Wago terminal blocks. They also come in different sizes, and for a different number of wires to be connected - two, three, five, eight.
They can join together both mono-cores and stranded wires.
Moreover, this can be implemented both in different types of Vago, and in one single one. 
For stranded wires, the terminal must have a latch-flag, which, when open, allows you to easily insert the wire and clamp it inside after clicking it. 
These terminal blocks in home wiring, according to the manufacturer, can easily withstand a load of up to 24A (light, sockets).
There are also some compact specimens on 32A-41A. 
Here are the most popular types of Wago clamps, their markings, characteristics and what section they are designed for:
Series 2273 Series 221-222 Series 243 Series 773 Series 224
There is also an industrial series for cable cross-sections up to 95mm2. Their terminals are really large, but the principle of operation is almost the same as that of small ones. 
When you measure the load on such clamps, with a current value of more than 200A, and at the same time you see that nothing burns and does not heat up, 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 rightfully be called the simplest, most modern and convenient to install.
Violate any of the above conditions and the result will be quite natural. 
Therefore, you do not need to put wago at 24A and at the same time protect such wiring with a 25A machine. In this case, the contact will burn out in case of overload.
Always choose the right wagon terminal blocks.
Automatic machines, as a rule, you already have, and they primarily protect the electrical wiring, and not the load and the end consumer.
There is also a fairly old type of connection, such as terminal blocks. ZVI - screw insulated clamp.
In appearance, this is a very simple screw connection of wires to each other. Again, it happens for different sections and various shapes.
Here are their technical characteristics (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 specifically do not choose large pads and shove several veins there. What to do is not recommended. 
Such a screw connection is well suited for mono-conductors, but not for stranded flexible wires.
For flexible wires, you will have to press them with NSHVI tips and incur additional costs. 
On the network, you can find videos where, as an experiment, the contact resistances are measured with a microohmmeter on different types of connections.
Surprisingly, the screw terminals have the smallest value.
But it should not be forgotten 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.
Compound of copper and aluminum
Often there is a situation when it is necessary to connect a copper conductor with an aluminum one. Since the chemical properties of copper and aluminum are different, direct contact between them, when oxygen is available, leads to oxidation. Often, even copper contacts on circuit breakers are susceptible to this phenomenon. 
An oxide film forms, resistance increases, and heating occurs. It is recommended to use 3 options here to avoid this:
They remove direct contact between aluminum and copper. Communication takes place 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.
For joining copper wires, GML sleeves are most often used. It stands for:
- G ilza
- M single
- L married
For connecting pure aluminum - GA (aluminum sleeve):
For the transition from copper to aluminum, special transitional GAMs:
What is the crimping method? Everything is simple enough. Take two conductors, strip them 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. 
Despite the obvious simplicity, there are several rules and nuances in this procedure, if not observed, you can easily ruin a seemingly reliable contact. Read about these mistakes and how to avoid them in the articles ”” and ””.
A hydraulic press is used to work with conductors of large cross-sections 35mm2-240mm2. 
Up to a cross-section of 35mm2, a mechanical handle with a large swing can be used. 
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 liner size.
For example, when connecting mono-cores, the sleeve is usually taken to the size of the smaller section.
And in this way, several conductors can be connected at one point at the same time. In this case, only one sleeve will be used. 
The main thing is to completely fill its internal space. If you crimp three conductors at the same time, and you still have voids inside, then you need to “fill” this free space with additional pieces of the same wire, or conductors of a smaller cross-section.
Crimping by sleeve is one of the most versatile and reliable connections, especially when it is necessary to extend the cable, including the lead-in.
At the same time, the insulation is obtained practically equivalent to the main one, when the outer tube HER is also used as a casing.
Certainly neither PPE, nor Wago, you will not use for these purposes, but the GML sleeves are the very thing! At the same time, everything comes out compactly and is easily reduced even in a strobe, even in a cable channel.
Welding and brazing
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 mono-conductor wire with a flexible copper stranded one. In addition, you are forever tied to an outlet or extension cord.
And if there is no voltage or generator nearby? 
At the same time, on the contrary, elementary press tongs are present in 90% of electrical installers. It is not necessary to purchase the most expensive and sophisticated ones for this. 
For example, rechargeable. Conveniently, of course, go and just press the button.
The Chinese counterparts also do their job well. Moreover, the whole process takes no more than 1 minute in time.
Requirements are requirements, and the most common type of connection is twisting. Where quick installation is required, terminal blocks of various shapes are used. One of the types of terminal connections are spring terminals. Wago products are especially popular.
To perform a branch without breaking the line, clamps are used, which are called nuts among electricians. It is a kind of terminal connection.
Using Terminal Blocks
The terminal block consists of contacts fixed on a plate made of insulating material. The contact plate has a screw on both sides, which tightens the wire. This allows on one side of the plate to press the copper wire, and on the other side the aluminum wire without fear of chemical interaction of these metals.
Different types of wires can be connected. On the one hand, a single-core wire can be fixed to the plate, and on the other, a stranded one. Another problem that can be easily solved with a terminal block is the connection of wires with different core diameters.
The terminal block can consist of one or more contact plates, which is very convenient in terms of installation. To do this, it is enough to collect the required number of plates and fix it in the right place.
Spring terminals
Terminals of this type are very similar in design to terminal blocks. The difference is that a spring-loaded plate is used as a clamp. Using spring terminals is very simple - you need to strip the wire to the depth of the terminal.
The pressure plate is removed and the stripped wire is inserted into the terminal. The wire is inserted so that there are no exposed sections of the wire. Then the pressure plate snaps into place and the process is complete.
Spring terminals can be used to mount single-core, multi-core wires and wires of different diameters. Installation of wires from different metals is allowed. The most widespread are the contacts of the Wago company, in which bimetal plates with a special contact paste against metal oxidation are embedded.
Installing PPE caps
PPE caps are often used when wiring. In appearance, they are very similar to the back plastic cap of a ballpoint pen. A spring in the form of a cone is laid inside it. The spring is anodized with an oxidation-resistant metal.
To connect the wires must be stripped to a length of 10 - 15 mm and fold the trimmed areas into one bundle. The ends of the bundle are inserted into a cap, which is then screwed onto them until it stops. The PPE cap can connect several wires, the total cross-section of which will not exceed 20 mm².
They are available in different standard sizes, so it's easy to choose the ones you need. The caps are color-coded, which is convenient for highlighting the phase or neutral wire.
| PPE brand | Number and cross-section of cores in mm² | Cap color |
| PPE - 1 | 2 x 1.5 | Gray |
| PPE - 2 | 3 x 1.5 | Blue |
| PPE - 3 | 2 x 2.5 | Orange |
| PPE - 4 | 4 x 2.5 | Yellow |
| PPE - 5 | 8 x 2.5 | Red |
PPE caps can significantly increase the installation time, because this connection does not require additional insulation. The material of the cap is made of non-combustible material and will not provoke spontaneous combustion if overheated at the junction.
The connection quality of PPE caps is worse than terminal ones and does not allow connecting wires made of different metals.
Crimping with special sleeves
Where it is necessary to create a high-quality and reliable connection, special sleeves can be used. The sleeve is a piece of copper tube of the required diameter. The diameter of the sleeve is selected depending on the total diameter of the wires to be connected.
The stripped wire ends are inserted into the sleeve and clamped. Then a heat-shrinkable tube is put on the sleeve, with which this sleeve is insulated. If no heat shrink tubing is available, you can use a cambric or electrical tape. The wires can be inserted into the sleeve from one or both sides. For crimping, they try to use special hand-held pressing tongs.
With this connection, the sleeve cannot be used twice. During repairs, it is simply thrown away. By using the hand-held stripping pliers and pressing tongs, the installation can be performed with good performance.
Soldering or welding
Installation using soldering is not very often used. Soldering always guarantees a secure connection. The contact has low resistance and good mechanical strength. Brazed wires are less susceptible to damage due to ingress of moisture.
To connect by soldering, it is necessary to strip the wires by 40 - 50 mm, irradiate with rosin and twist. Then, solder is applied to the twisted ends, heated up until it spreads evenly over the entire twist and flows inside. The appearance of the soldered wires should be shiny.
After soldering, the sharp ends are processed to prevent damage to the insulating material. Any available type can be used as insulation.
Such a connection can be attributed to the most laborious. The soldering process requires certain skills. Installation in this way at a height with improvised means is not very convenient. When soldering, it is necessary to leave some margin in case of repair.
In some cases, contact welding is used. The process itself is similar to the soldering method, but the stripped twisted wires are not covered with solder. A welding transformer is used for the connection. The ends of the wires are heated until they fuse into a single metal ball.
A heat-shrinkable tube is put on the welded ends for insulation or wrapped with electrical tape.
Twisting and insulation
Twisting is completely rejected by the rules of the PUE, but in practice, twisting of wires is used almost everywhere. But twisting must be able to do and then it will last more than one decade. For this, the wires are stripped with such a calculation. That the twist should be at least 4 - 5 cm long.
The cleaned areas are cleaned from the oxide film with a knife blade or fine sandpaper. The ends of the wires are crossed at a certain angle at the end of the insulation and tightly twisted with pliers. The twist should be flat and tight. From above it is insulated with the existing insulation.
A twist connection cannot be made for wires of different cross-sections. Do not twist wires made of different metals. It is not allowed to twist a single-core wire with a stranded one. Such a connection is used only where there is no fire-technical acceptance of repair.
Clamp "nut"
A branch clamp of the "nut" type is intended for making branches from the main wires without breaking. At the point where the tap is connected, a section of insulation is removed and a "nut" is attached to this place. The clamp consists of a carbolite body and a steel clamp. The clamp consists of two plates and screws. Each plate has a recess for a certain wire cross-section.
One plate is placed under the wire, and on top is covered with another plate. Both plates are clamped with screws, and between them a wire and a branch. To choose the right "nut" depending on the diameter of the wire, you must use the table.
| Clamp type | Line section mm² | Bend section mm² | Clamp dimensions |
| U731M | 4 – 10 | 1.5 – 10 | 42 x 41 x 31 |
| U733M | 16 – 35 | 1.5 – 10 | 42 x 41 x 31 |
| U734M | 16 – 35 | 16 – 25 | 42 x 41 x 31 |
| U739M | 4 – 10 | 1.5 – 2.5 | 42 x 36 x 23 |
| U859M | 50 – 70 | 4 – 35 | 62 x 61 x 43.5 |
| U870M | 95 – 150 | 16 – 50 | 84 x 85 x 60 |
| U871M | 95 – 150 | 50 – 95 | 84 x 85 x 60 |
| U872M | 95 — 150 | 95 — 120 | 84 x 85 x 60 |
To make the connection, the carbolite body must be disassembled. It consists of two halves compressed by two retaining rings. If the rings are pry on and removed, the body will disintegrate. If the wires are of different metals, then an additional plate must be used. It will prevent the contact of different metals and further oxidation, which will worsen the contact. The screws are tightened with reasonable torque and inserted into the case.
Bolt use
The bolt connection is used most often when it is necessary to connect copper and aluminum wires. Stripped wires are put on a regular steel bolt, and steel washers and a Grover washer are put on between them. The entire "sandwich" is pulled together and wrapped with electrical tape.
What if there are several wires?
A terminal block can be used to connect multiple wires. To do this, connect one half of the contact plates with one wire. The number of such plates should be equal to the number of wires. The rest of the wires are attached to the opposite contacts of the plates.
You can take a terminal block with the number of plates equal to the number of wires divided in half. Then one half of the wires is clamped on one half, and the other half on the other half of the contacts.
Multiple wires can be connected with a bolt. Lay a steel washer between the wires, and put a Grover washer under the nut.
Identical wires can be connected using a PPE cap using a known technology or by welding.
What if the veins are of different cross-sections?
If it is necessary to connect wires with conductors of different cross-sections, then you can apply:
- Soldering or welding;
- Bolted connection;
- Connection with self-clamping terminals;
- Screw clamps;
- Branch clamp;
- Copper lugs and bolting.
Combining stranded and single-core products
The connection of stranded and solid wires can be done by applying:
- Soldered connection;
- Connection with special sleeves;
- Terminal connections;
- Connection by lugs.
How to carry out work in water and on land?
All street wiring must be carefully protected from moisture. For laying, it is necessary to choose cable products that are designed for such work. The cable must have at least two insulating layers. In addition to the existing insulation, the wire must be placed in a corrugation. For laying in the ground - in a pipe with sealed couplings.
All sockets, switches, lamps and other elements must be made in the appropriate design. On water, only low voltage is used for power supply. All connecting elements are located above the water level.