When laying wiring in the house, you cannot do without connecting the wires. After all, a network with branches is laid around the house to power certain electrical appliances.
Distribution boxes are used to branch the electrical network. But they are intended only to hide the connections of power network branches.
The need for wiring connections is found everywhere. Connect different ways wiring in the house, electrical appliances, cars, in general, wherever there are wires.
Nowadays, several methods of connecting wiring are used. Each of them has its own positive and negative qualities.
The most common ways are:
The simplest and most common way to connect wires is ordinary twisting.
For this type of connection, all the equipment required is a knife for stripping the insulation and pliers to ensure a reliable connection. However, at the end, the place of twisting will need to be insulated.
Twisting is done in several ways.
The simplest is mutual twisting of the stripped ends of the wiring.
For reliability, it is advisable to expose the wires by at least 5 cm. Next, the exposed ends are crossed so that the edges of the insulation touch, and then the crosshairs of the wires are grabbed with pliers and rotational movement twist them.
After twisting, the connection is bent to one side so that the twist lies parallel to the wire. The connection is then isolated.
The second method is also effective and simple twisting.
The stripped ends of the wires are slightly bent in the middle, and at the bend the wires engage with each other.
After the end of one wire is wrapped around the second, the same is done with the other end of the wiring.
For reliability, the made windings can be slightly tightened with pliers. Then everything is isolated.
The next method is a bandage connection. For such twisting you will need a piece of stripped wire.
The two wires to be connected are placed parallel to each other so that the stripped ends touch along the entire length.
Then they are wrapped with the available piece, creating a kind of bandage.
The last of the used twisting methods that you can find is groove twisting.
To do this, small hooks are made from the ends of the wires, which are interconnected, and then one edge of the wire is wound around the other.
More complex species The wire connections are shown below.
Now about ways to isolate twists.
Often used for insulation different types electrical tape. When using it, you need to wrap not only the place of twisting, it should extend at least 2-3 cm onto the wire insulation.
This will ensure complete insulation, including from moisture.
In addition to electrical tape, it is possible to use thermal tubes.
Such a tube of the required length is placed on one of the wires before twisting.
After twisting, the tube is pushed onto the joint. In order for it to tightly grip the wiring, it needs to be heated a little, for example, with a lighter.
The temperature will cause the tube to shrink, creating a tight fit.
TO positive qualities twists can be attributed to the ease of implementation with minimal equipment, while they are considered quite reliable.
If good insulation is provided, the twist can last a long time. Also, the twist itself is a detachable connection; you can twist it at any time.
It is considered more preferable in networks that are not fixed and can sag, which is especially important for cars where the wiring is constantly exposed to vibration.
One of the disadvantages is the impossibility of connecting wires of different sections; the resistance in such twisting can be very high, which will lead to heating and melting of the insulating layer.
It is difficult to combine multi-core cables by twisting. They are too soft, so when stretched, the connection may break.
If multiple insulated strands are used in the wiring, then after each strand is insulated, the total thickness at the junction can be very large.
This will affect both reliability and increased resistance at the junction of the wires.
The next method of connecting wires that is often used is soldering.
It is noteworthy that soldering is only an improvement in twisting. That is, the wires must be twisted before soldering and then soldered.
To perform soldering, a soldering iron and solder are used. Thanks to this connection, the twisting strength of a multi-core cable can be significantly increased.
The advantages of soldering include increased strength, especially for stranded wires.
After soldering, the resistance at the connection point will be significantly lower, which means the twist will not heat up.
However, soldering is only used on copper stranded wiring; aluminum wires cannot be soldered.
However, soldering is very fragile, and if done incorrectly, the connection will be unreliable.
Another way to improve twisting is welding. Again, welding is just a method of increasing the reliability of twisting.
It is not applicable for aluminum wires, welding is used only on copper cables large section.
Reliability when welding is much higher than when soldering. She happens to be in a good way improve connections in the junction box, but welding is still not very practical.
In addition, it will require special equipment, a welding inverter.
Welding is not used on aluminum wiring; an additional disadvantage is the possibility of weakening the twist, since if the wires are very heated, which will be necessary during the welding process, the twist itself may weaken due to a change physical properties metal
Soldering and welding cannot be considered separate connection methods; they only provide additional reliability.
Also after using a soldering iron or welding machine The connection point will still have to be insulated.
But the use of terminal blocks and blocks is completely separate method wire connections.
The terminal block and block are a small metal plate with contacts on the edges.
This plate is encased in insulating plastic. Bolts are often used to clamp wires.
The difference between a terminal block and a block comes down to the fact that the terminal block allows you to connect only two wires, while the block is designed for several connections.
Simply put, a block is several terminal strips connected together to provide several separate connections.
To connect two wires, it is enough to clean their ends of insulation, and you don’t need to clean much, 0.5 cm is enough, it is only important that the cleaned end reaches the contact.
In this case, the bare wire should not protrude beyond the edges of the terminal block, in order to avoid accidental contact with it.
On the other side of the terminal block, the other end of the wire is fixed. The metal plate will act as a bridge between them.
When using a terminal block, they connect only two wires; for subsequent ones, another terminal block is used.
The block allows you to provide several connections, which when large quantities wires will result in more compact sizes.
Terminal blocks and blocks are good because they allow you to connect together wiring made of different metals and differing in cross-section.
In addition, they are detachable, so you can disconnect the desired wire at any time. They are good for both single-core and stranded wires.
Their disadvantages include the increased dimensions of the connection, especially for the pads.
Hiding terminal blocks and strips can be very difficult. In addition, ordinary terminal blocks will not allow insertion into the wiring; twisting allows this. But about the sidebar - a little lower.
Self-clamping terminal blocks are a type of conventional terminal blocks. They provide an even faster connection because you don't even need to use a screwdriver.
The contacts in them are spring-loaded, so to connect the cables it is enough to insert the ends of the wires into the holes with the contacts.
During installation, you need to overcome the force of the spring, after which it will press the contact to the wire. It is noted that this method is very convenient for multi-core wires.
Among the disadvantages of such a connection is that the connection is not particularly reliable; it will not be difficult to pull out the wiring from the terminal block. This is especially true for single-core wires with a large cross-section.
A common disadvantage of terminal blocks is the possibility of moisture getting on the contacts, which can lead to their oxidation and disruption of the connection.
PPE caps – simple and convenient way connections. They are produced in three types - without contacts, as well as with clamping and spring-loaded contacts.
Caps without contacts are made only of insulating material. They are intended for insulating twists.
They are placed on top of the twist, protecting it from moisture.
Twisting wires is prohibited by the pros!
Not long ago, at one site in Minsk, I saw electricians who were twisting wires and smearing them into the walls. To my remark, they made excuses that they do everything that way. It turned out that the guys came from the region, and for them this method of connection is common practice - cheap and fast. For such “masters” I would like to remind you that twisting wires and leaving them like that is... IT IS FORBIDDEN!
According to technical standards in the Republic of Belarus, ordinary Twisting in electrical wiring is prohibited :
Indeed, the PUE does not allow the use of twisting to connect wires. However copper twist, if made by a professional craftsman, can easily hold a load of 16 A, without any negative consequences. If the load is greater, the contact will deteriorate and burn out over time.
There is another interesting paradox: despite the fact that twisting is strongly criticized, all the burned twists that I have seen were performed not professional. Most of them were aluminum. Aluminum is generally a very capricious conductor; it behaves poorly in any connection and requires special attention. But even such twists can cope with household loads in apartments.
However, despite this, twists are evil. Why?
Firstly, they have a high transition resistance and secondly, they are very sensitive to pulse currents. In addition, not everyone knows how to do twists correctly.
What should the twist be? Correct twist should be 3-5 cm long (depending on the cross-section and number of strands - the thicker and larger, the longer), twisted tightly but “without wings”.
Typical mistakes when twisting:
In the photo, I tried to imitate the incorrect wire connections that I encountered in apartment wiring:
Another of the most common types of connections is twisting an aluminum core with a copper one:
and connection of a mono core and a stranded wire:
All this is an example of bad connections. Use such connections in electrical wiring - IT IS FORBIDDEN!
Where can you use TWISTING WIRES?
I use regular wire twisting only as a temporary connection or as a preparatory operation for other types of connections (for example, welding or soldering).
Summary: Twisting is bad! Use reliable types of connections: welding, crimping, 3M clamps.
According to clause 2.1.21. PUE, connections of wires and cables must be carried out in one of the following ways: welding, crimping, using screw or bolted connections, or soldering in accordance with the current instructions approved in in the prescribed manner. As you can see, “twisting” is not mentioned here at all. We can safely conclude: twisting is practically prohibited by the PUE.
However, let's figure out why the official attitude towards twisting is so clear, what may be the reason for its exclusion from the list of permitted methods of connecting wires, because it is absolutely clear that this was done for a reason. Allowed: crimping, soldering, welding and screw connections. Let's start by looking at what the features of the permitted connection methods are, and how they differ from twisting.
Soldering and welding
Soldering and welding assume solidity and the maximum possible conductivity of the permanent connection being created. During soldering, the permanent joint formed is formed by interatomic bonds, because when the metals being connected are heated below their melting point, the solder is already molten, it immediately wets them and flows into the gap, after which it crystallizes.
Welding also involves the establishment of interatomic bonds between the parts being welded, but here the metals themselves melt or undergo plastic deformation (or undergo both melting and deformation).
One way or another, it is now clear to us that soldering and welding of wires makes their pairing as complete and high-quality as possible, because the wires are combined at the atomic level, which means that for current they are turned into a single wire, when there are no air gaps at the transition between the parts being combined, there are no unnecessary intermediate elements that could somehow impair conductivity.
Crimping and screw connection
As for crimping and screw connections, this involves pressing the mating conductors so strongly against each other that the quality of the connection is almost identical in conductivity level to a welded connection or junction.
Yes, the tensile strength of such a connection may be less than that achievable by welding or soldering, but the achieved conductivity of the joint turns out to be almost the maximum possible, since the wires can be said to flow into each other, their metals diffuse. There is not even an intermediate element - solder, the resistivity of which, in principle, can be greater than the resistivity of the metals of the wires being connected.
If the purpose of the connected wires is such that the wires will not bear a significant mechanical load, then crimping or a screw connection is in no way inferior to welding and soldering in terms of conductivity.
Why does the twist heat up?
What about the twist? Twisting will not only not allow you to create a reliable, well-conducting contact, it will also not provide strength and will heat up more than the rest of the wire when any significant current passes through it.
This will happen because at the point of twisting the wires are not connected at the atomic level, they are only in contact with part of their surfaces, and here and there there are air gaps between them in which oxides will certainly begin to form over time.
In addition, the mechanical twist will still unravel over time, which will further aggravate the formation of oxidation products.
In the end, due to the combined action of these factors, the contact of the wires in the twist will deteriorate so much that this can lead to the formation of sparks and even fire of the wire insulation.
Of course, if we're talking about about the temporary connection of wires, for example, while testing the circuit for switching on some load or when checking a part of some device being repaired, then in these cases no one will forbid you to carefully use elementary detachable connections - twists.
However, one should remember the obvious disadvantages of such a solution as twisting and the inevitable long-term consequences of its use. Therefore, please make permanent connections only using methods approved by the PUE.
Twisting of wires is used to provide connections and branches during electrical installation operations. Contacts with this method of switching must be reliable. Carrying out work on wiring of all types - in everyday life or in industry - is subject to a collection of requirements and rules on how to properly twist wires. They say that it is impossible for additional resistance to appear at the points of contact between the cores. Neglecting this rule will lead to heating of the contact point.
The connection is made in accordance with electrical safety standards using similar methods:
Connecting wires by twisting implies the advantages and disadvantages of the method. There is a PUE regulation prohibiting such an operation. But despite this, twisting is often used.
Twisting of contacts occurs during rough installation. This is explained by the need to establish the correct operation of already installed connections. Check integrity electrical lines, introduce the necessary amendments, install additional devices:
Upon completion of the preliminary work, completely assembled circuit passes the functionality test. In case of incorrect operation of equipment, lack of electricity determine the cause and area of damage. We have to replace faulty components and twist the wires correctly.
Correct twisting of the wires makes it possible to quickly restore the power supply. Depending on the situation, they decide what to do with the elements of annexation:
Therefore, it is worth considering the maximum number of connected devices, deciding how to twist the wires correctly, calculating the appropriate cable cross-section, further development energy systems in the event of an increase in the number of consumers. Then the mounted solder will serve reliably for more than one year.
Twisting cable strands to connect pieces of wiring to each other appeared immediately after the discovery of electricity. At first, this method suited everyone. But time does not stand still, new electrical equipment has appeared, the need for development has increased energy networks with increased power and current. The question arose of how to properly twist the wires in the increasingly complex realities. Twisting is no longer guaranteed in such conditions uninterrupted operation. But on household level it is widely used and meets the requirements of low-load networks.
The advantages of a braided connection are:
There are also many disadvantages:
Such combinations are strictly prohibited for use. It is unacceptable to combine copper and aluminum wire! When touched, these metals enter into chemical reaction oxidation, galvanized . Contact connection is destroyed. As the load on the chain increases, weld erosion accelerates. Connecting in such conditions leads to sad results:
The influence of air on the conductors oxidizes the junction. For copper and aluminum conductors, such an aggressive environment shortens their service life. Application expensive metals like silver or gold in conventional schemes it is not economically feasible. The problem is solved by insulating the strands with high-quality dielectric material with using the right methods execution. Such measures prolong the trouble-free operation of the soldering point and the entire circuit.
The result of weak contact between the cable cores is an increase in resistance in this place. Heating appears in the transition space and destruction of the entire connecting circuit. Tight connection of the wires will reduce such risks.
Twists are classified according to the material of manufacture of the veins involved in the operation, their types, and the method of twisting. The cross-sectional areas and permissible load must be identical.
Wires with copper conductors allow repeated, up to ten times, torsion without compromising strength and contact. They easily also suitable for triple-quadruple connections. Aluminum cable is not as resistant to mechanical impact. One or two attempts at gossip - and he breaks off.
Cable cores can be single or multi-wire. The twisting method must be found taking this feature into account.
For temporary or mobile wiring, choose a more reusable twisted soft cord. The stationary and final electrical circuit consists of a monolithic core.
Connecting multi-wire cables is allowed. The directories contain data for all types. Following the numbers, materials are selected for installation from wires with different combinations lived It is necessary to take into account the cross section according to the current rating. The methods of weaving such endings do not differ.
The connection of wires will last for many years if the exact manufacturing procedure is followed.
We do this with the following veins.
The TU cambric is moved to the joint and heated until it is monolithically applied to the twisted area. In the absence of a tube, insulating tape is used. It is applied in three to four layers with a full overlap.
In the absence of special devices for splicing cables, we use twisting. The main requirement is the maximum contact area of the cores at the point of alignment. After stripping, we twist each wire at the sheath by one centimeter. We fluff out the bare ends into the hairs. Manipulation is performed with each contact.
Serial connection is made by combining counter beams one into another so that the wiring of the cores got mixed up with each other. Twisting is done from both sides in opposite directions.
When installed in parallel, the manipulations are close. The wires are arranged like a house and the fluffy corollas are braided. The connections are sealed with pliers and insulated.
The easiest method soldering of single-wire conductors is called parallel. The wires are brought together at an arbitrary angle, the stripped areas are twisted away from the point of adhesion.
To build up using a simple sequential interweaving method, the bare wires are bent, moved towards each other until they intersect and twisted with a screw in opposite directions.
When one wire, before connection, is bent and curled around the second in 2 places (at the insulation and in the area of its bent edge), the cable is spliced by parallel intersection with the gutter.
Similar consistent Twisting is done with braiding of both cores. Two twisted spots are formed at the base of the insulating layer.
Connection with the assistance of a bandage is required when working with a rigid wire or cable with a large cross-section. This technique also has parallel and sequential versions. A core is pre-prepared from a monolithic wire of a thinner cross-section, soft and made of a material similar to the main cable. The stripped ends are bent at right angles and brought closer to each other. The prepared bandage core wraps around them in uniform turns.
The connection of an additional wire and a branch for each option occurs in a parallel way. The branching of the bandage differs in that, that only the attached process is wrapped.
With the intensive development of electronic technology, the load on electrical networks increases. Requirements for the reliability of soldering of current supply branches are also growing. The twisting method is gradually becoming a thing of the past. This is clearly noticeable in production areas, where installation is carried out using progressive methods, and outdated joints are replaced.
No matter how widespread they are Lately a variety of clamps and terminals; the most popular way to connect wires is simple twisting. However, you should know that electrical installation rules prohibit the use of twisting in pure form(i.e. no further soldering or welding of the contact). You can increase the “legality” of twisting with the help of PPE. You make a twist, and on top of it you screw the PPE (connecting insulating clip).
It creates sufficient contact density and does not allow the contact to loosen under different loads and temperature changes. Choose PPE the right size, quantity and quality with free shipping Can .
Firstly, remember that wires come in aluminum and copper. Copper wires are divided into monocore (one solid core) and multicore (flexible).
Mono-cores are used for fixed connection equipment. Once I laid it under the plaster, behind the drywall and forgot about them. There is no longer any need to move or bend such wiring.
Multi-core cables are used for mobile devices or temporary connection of electrical equipment. Where wiring constantly needs to be moved from place to place, its location must be changed. These are home carriers, Appliances plugged into sockets. 
They are also used in the assembly of panel boards, where there is a shortage of free space, and the cores have to be bent significantly in order to be inserted into the terminals of the devices.
Let's first consider how to properly twist wires from a single core. The process here is not complicated and is known to everyone. Take two wires, strip them at the ends and begin to twist each other.
The Chinese even came up with an assistant attachment in this matter to automate the work. 
Main features and rules:
Twists of aluminum and copper wires are performed in the same way. The difference is that you can unscrew and tighten copper ones several times, and aluminum ones 1-2 times. After which they will break off. 
What if you need to twist more than two wires, say 4-5? The process is no different:
There are situations when it is necessary for twisting to take as long as possible less space. Either there is not enough space in the junction box, or it must then be pulled through a narrow hole. In this case, the technology is slightly different.
In terms of quality and reliability, such twists are inferior to conventional ones.
Directly twist copper wire and aluminum is not allowed. Such a connection will oxidize and subsequently can lead, at best, to burnout of the contact or, at worst, to a fire. 
In such cases, you need to use either connectors, or use a third metal - steel, as a spacer between copper and aluminum.
Take a simple bolt with a nut and washer. The stripped wires are shaped into a ring at the end. And these rings fit on the bolt. Moreover, the wire of the ring should bend in the direction of the bolt thread. 
The aluminum core is clamped with a steel washer, and a copper washer is placed on top of this washer. After which the contact is tightened with another washer and nut. That is, to create normal contact between a copper conductor and an aluminum one, you will need at least a bolt with a nut and 3 steel washers.
You can apply the previous descriptions of work for such conductors, but this will not provide reliable mechanical contact. Therefore, proceed as follows.
