How to connect the wires correctly. How to connect wires in a junction box. How to connect stranded and solid wires - and do it correctly Wiring using clamps

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

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

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

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

How to connect wires correctly

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

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

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

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

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

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

Damage to insulation/core

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

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

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

How to twist wires correctly

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

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

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

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

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

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

Why is it better to crimp (crimp) wires?

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

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

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

Soldering as a reliable alternative to twisting

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

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

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

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

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

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

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

But welding is still preferable

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

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

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

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

Terminal blocks are the most ergonomic electrical installation products

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

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

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

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

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

Any man strives to ensure that the electricity supply in his own home or apartment is of high quality, uninterrupted and reliable. Therefore, when carrying out electrical installation work during construction or repairs, it is necessary to correctly connect electrical wires. But in everyday life you still have to face problems when the lamp wire broke, the socket stopped working. Of course, if you have basic knowledge of electrical engineering and the ability to carry out electrical installation work, it is easy to fix all these faults yourself.

The connection of conductors made of different metals must be made taking into account all the properties of the material from which they are made. Currently, copper, aluminum and steel are used to transmit electrical energy. Each of these metals has different densities, conductivities, and resistances that are taken into account when making good electrical contact. It is also necessary to take into account the magnitude of the electrochemical potential that arises when current is applied to the metal.

Therefore, if aluminum and copper conductors are connected incorrectly, problems may occur. serious problems problems that many specialists who repair wiring in apartments encounter. Previously used in homes copper wires, which were much superior to aluminum ones in terms of electrical performance. And currently use of copper conductors faded into the background.

Aluminum, having a high level of oxidation, forms a specific film when combined, which has a fairly high electrical resistance. This property manifests itself especially in humid environments. The same film is formed on copper, only its resistance is much lower. Therefore, due to this difference in resistance, direct connection of these metals results in difficult electrical conductivity. A oxidation processes lead to sparking, heating and fire of wires.

Methods for safe contact

To create reliable contact between electrical wires, there are several methods, both using special equipment and using improvised means.

Types of wire connections:

1. Twisting (twisting) is the most common method, the use of which is desirable for temporary connections.
2. Welding is the most reliable method that ensures excellent contact of conductors. Requires welding equipment and certain skills to carry out the work.
3. Soldering - has excellent connection performance, but requires compliance with the temperature regime (not higher than 65℃).
4. Terminal blocks are a fairly simple and reliable connection.
5. Connecting wires using clamps - subject to operating conditions - allows you to get excellent contact. Installs very quickly.
6. Crimping with sleeves requires special pliers and knowledge of installation technology, but the method is very reliable.
7. Bolted connection - used in difficult situations, easy to perform and does not require special devices.

When choosing the type of connection, it is necessary to take into account: the material of the conductive part; wire section; number of conductors; type of insulation; terms of Use. Most often, the selection of the type of connection is carried out at the work site.

This technological operation is common to all methods of connecting conductors. Before combining the wires into a common electrical unit, it is necessary to strip them of the insulation layer.

The easiest way to do this work is with a mechanic's knife, but in this case there is a possibility of damage to the conductive core. To avoid this, you need to:

1. Place the wire on the table surface.
2. Press it with the index finger of your left hand.
3. Holding the knife in your right hand, cut the insulation. In this case, it is necessary to direct the blade at an angle to the cut so as not to damage the core. Otherwise, the conductor may break.
4. Using the finger of your left hand, twist the conductor one turn to cut the insulation.
5. Remove the cut piece of the insulating sheath.

Experienced electricians have in their arsenal a multifunctional tool - a stripper, which is designed for cutting cables and removing insulation. This device does not damage the core when removing insulation from a conductor of any cross-section, since it has a special calibrated recess for the required wire diameter.

The length of insulation stripping is selected in accordance with the method of connecting the conductors.

The simplest and most well-known method of connecting electrical wires is twisting them (twisting). Experienced electricians often call it the old-fashioned method.

Previously, this type of connection was used everywhere, but with increasing load in the electrical network in a modern apartment, twisting has become prohibited. However, this connection method must be studied first, since it is the main step in soldering and welding wires.

The main advantage of twisting is the absence of any material costs, since you only need pliers and a knife to remove the insulation. And of course, the advantage of twisting is the ease of its execution. Anyone who has held pliers in their hands can do this job without any problems.

Over time, the twist weakens, which is its main disadvantage. This process is connected with the fact that in any veins there is residual elastic deformation. Therefore, at the point of twisting, the contact resistance increases, which leads to weakening of the contact and heating of the conductor. It would be good if this defect is discovered in time and the junction can be redone, but a fire may occur.

But if for some reason you do not have the opportunity to use more reliable methods, then you definitely need to familiarize yourself with how to properly connect the wires to each other using the twisting method. To do this, you first need to strip the cores of 70-80 mm of insulation. Then, holding both conductors where the insulation ends, use pliers to grab the ends of the wires and rotate them clockwise. Main the condition for reliable twisting is the simultaneous rotation of the conductors, and not alternately winding them on each other.

If the diameter of the wires is small, then twisting can be done entirely by hand. With your left hand you need to hold the conductors along the cut of the insulation, and with your right hand you need to rotate the conductors by the bend (10-15 mm) clockwise. For tighter contact at the end of the rotation, you can use pliers.

The next step is to insulate the junction of the wires. Insulating tape is used for this. To ensure reliability and protect the contact from moisture, you need to wind the tape in several layers, while stepping 2-3 cm onto the wire insulation. A very good option for insulation is the use of thermal tubes; the main thing is not to forget to put it on one of the cores.

Professional electricians advise not to stop at the stage of twisting the wires, but to strengthen the joint by soldering or welding.

How to connect wires by soldering

The type of connection in which electrical wires are joined using molten solder is called soldering. This method is best applicable to wires with copper conductors, but the use of special fluxes allows you to obtain high-quality joints of other metals.

Advantages of using soldering:

• In terms of reliability, this type of connecting wires is second only to welding;
• allows you to connect both single-core and stranded wires, as well as wires with different sections;
• no maintenance of the contact point is required for the entire period of operation;
• low cost of work (flux and solder are inexpensive).

The disadvantage of soldering is considered to be rather high labor intensity. The surfaces to be soldered must be previously cleaned of oxides and tinned before twisting the wires.

An electrician must have certain qualifications and be able to use a soldering iron, because during the work it is necessary to strictly observe the temperature regime. A weakly heated or overheated contact point loses its reliability and strength.

The technological process for performing soldering looks like this:

1. The insulation is removed from the conductors by 40-50 mm.
2. Areas of exposed veins are well cleaned with sandpaper.
3. Tinning of wires is carried out. To do this, a heated soldering iron is dipped in rosin and the tip is passed several times over the cleaned surfaces.
4. The wires are twisted.
5. Place solder on the soldering iron tip and heat the twist. In this case, molten tin should fill all the gaps between the turns.
6. After cooling, the soldering is wiped with alcohol and insulated.

To create the most reliable connection of the conductors after twisting, they are additionally secured by welding. The technology for making such a contact is very similar to soldering, only here a welding machine is used instead of a soldering iron.

In terms of quality and reliability, the welding method fully meets all regulatory requirements for creating electrical contact.

When creating a connection by welding, the conductors are twisted and their tip is welded. The resulting metal ball provides a very reliable connection of the wires. At the same time, reliability is due not only to the creation of high electrical characteristics, but also mechanical ones.

The main disadvantage of this type of wire connection is the presence of a welding machine and devices for such work. In addition, it is necessary to strictly adhere to the rules of working at height and fire safety.

Sequence of welding wires:

1. We remove 60-70 mm of insulation from the conductors.
2. We clean the cores mechanically (sandpaper).
3. We twist the wires, and its length must be at least 50 mm.
4. We fix the welding grounding contact on top of the twist.
5. Lightly touch the bottom of the twist with the electrode. Wire welding occurs very quickly.
6. After the contact ball has cooled, we insulate it.

As a result of such actions, an almost solid conductor is obtained, and the contact node will have the lowest transition resistance.

For such a connection of conductors, special copper or aluminum sleeves are required, which are selected in accordance with the size of the bundle diameter. It is advisable to use the same material for the sleeves as that of the conductor.

The wires are stripped to the length of the sleeve, rolled up and placed in a tube. Then, using special pliers, the connection is pressed and insulated.

There are tube sleeves for extending conductors, that is, for attaching them longitudinally. The wires are inserted into such sleeves from different sides of the tube, then crimped individually.

Bolt method

This connection is used in electrical circuits with high voltage. Its use is suitable for switching almost any conductors.

• put the washer on the bolt;
• first conductor;
• next washer;
• second conductor;
• puck again;
• screw.

Then the assembled assembly is tightened by hand, and then pressed with a wrench or pliers.

Modern industry has mastered the production of special wire connectors, which have made work much easier and have sped up switching work:

1. Caps with built-in crimp spring. The stripped wires are inserted into such a cap and turned clockwise. With this action, the wires are securely compressed inside.
2. Terminal blocks, which have tubular brass sleeves inside. Bare wires are inserted into these sleeves and clamped with screws.
3. Self-clamping terminals The stripped wire is automatically fixed with a special plate.
4. Lever terminal blocks are considered reusable devices. Fixation of the conductor is ensured by raising and lowering the lever.

Remember that the connection of wires must always be made on de-energized electrical networks. Without knowledge of electrical engineering, it is better to entrust work involving dangerous voltage to specialists.

Modern life cannot be imagined without electrical appliances: a TV, computer, food processor, washing machine, iron, ironing unit, heater, fireplace, coffee grinder, kettle, refrigerator, etc. Well, it is absolutely impossible to imagine our life without electric lamps, which help us live comfortably in the evening, morning and night.

When entering a house at night, our hand first reaches for the switch. We vaguely imagine how people used to live without electricity. But in order to use electricity in our apartments, houses, garages, offices, it is necessary to supply this same electricity.

Electrical installation

Electricity is supplied to consumers through wires. It is important to know how to connect wires for this purpose throughout the apartment. Electrical installation of wires in apartments and houses is done based on what and where will be placed in the apartment, where lamps, lamps, floor lamps and all kinds of electrical appliances will be needed.

In order to install sockets and switches so that life is trouble-free, electrical installation must be carried out competently. The most common damage caused by current flowing through wires is usually an open circuit. This trouble usually manifests itself at the places where the wires are connected (twists, terminals, clamps). With such a breakdown, the consequences can be disastrous. Let's look at how to connect the wires correctly. There are some peculiarities here. Failure to comply with certain rules can lead to malfunctions in the electrical system and even fire.

How to connect copper wires

Copper wires can be connected in any way - twisting, soldering, screwing, terminal blocks, etc. Switching from aluminum to copper wires improves the quality of connections. Since 2001, risers have been prescribed to be made only with copper wires and to switch to the same conductors everywhere. approved for use by consumers with a previously known, constant, guaranteed power. For sockets that provide operation of household appliances, where the load is constantly changing, only copper cables and wires are used. In construction, aluminum is used for external electrical wiring (underground cables, overhead lines, etc.) according to existing standards. Today, many houses are still equipped with aluminum wiring, and no one is going to convert it all to copper. But during renovations, for example, changes in the location of sockets occur in apartments. Here it is necessary to remember that contact of these two materials is unacceptable.

Branch squeezes

To branch from a whole wire, branch clamps are used. Electricians affectionately call them “nuts” because of their similarity to the walnut body.

They are arranged as follows: these are two steel plates in which there are grooves for conductors and they are compressed by four screws, and between them there is also a flat plate that separates the copper and aluminum wires. Such models are available for both home and outdoor use. They are mainly used for draining into apartments from an aluminum riser.

How to connect two wires?

The simplest thing is to twist the wires and fix them by soldering, but this takes a long time. It’s easier to use a terminal block where the twist is inserted and tightened with one or two screws. In this case, it is important to apply pressure with a flat plate so as not to cut the wires. When there is no such plate, it is necessary to solder or put a thin-walled tip on the twist - this prevents the destruction of the wires in the terminal. Soldering is carried out mainly on soft stranded conductors, and this leads to mechanical stress, displacement of the wire and breakage at the end of the tinned section.

Moving away from simple twisting

Anyone who wants to do something with electrical wiring on their own: install a socket, switch, asks themselves the question of how to connect the wires? Previously, they simply twisted two wires (or more) and insulated them, but this was often unsafe and clumsy.

The situation is changing for the better every year. When connecting rigid single-wire conductors, they are fixed with caps, soldering, spring terminals, welding, and screw clamps. In mass construction, connections were previously fixed with plastic caps. Now they are widely used and available to everyone. Inside the caps there is a special gel that prevents oxidation, or a conical spring that is screwed onto twisted connections, like a thread. Spring caps are used for a certain number of wires: two 4 sq. each. mm or four 1.5 sq. mm and no more.

Nowadays a newer three-wire circuit is used, and it is safer than a two-wire one. The new implemented scheme is when no current flows through the protective conductor in operating mode, and therefore the connections made do not experience stress.

Nowadays, for electrical installation work, flexible, multi-core PVA is preferred (“P” - wire; “B” - insulation and sheath of PVC plastic compound (vinyl); “C” - connecting), which is produced in accordance with GOST 7399-97. Designed for connecting electrical appliances, household and similar machines to electrical networks with rated alternating voltage up to 380 V and for 380/660 V systems).

Isolating connections

How to connect two wires, ensuring tightness? There is insulating tape for this. According to the PUE, insulation with tape must be done in at least three layers, both cotton and vinyl.

Cotton tape is more heat resistant. It can withstand 70-80 degrees, vinyl is less stable and flows at 50-60. But over time, cotton material loses its water-repellent properties and begins to absorb water. In this regard, for greater tightness and heat resistance, the inner layer of insulation is made of fabric, and the outer layer is made of vinyl.

Spring terminal connection

How to connect copper wires to aluminum? Spring terminals are very good for home use. The stripped wire is inserted into the hole and there it is secured with a spring. Such devices are available for soft and hard wires. In this device, it is easy to connect copper and aluminum wires because they do not contact each other, and this eliminates electrocorrosion. Moreover, the gel inside eats up the oxide film on the aluminum. You can connect wires of different diameters and only the number for which the terminals are designed. When connecting more than two wires (maybe of different cross-sections), not only spring terminals, but also ordinary terminal blocks are suitable.

Terminal block connections

Professional electricians most often use They have many insulated sockets with screws (usually two). We put a wire under one in the socket, and with the other we press the comb, which connects all the sockets of the block together. The required number of cells is cut off with a knife or hacksaw.

Very comfortable single clamp pads. The two wires inserted into the hole are secured with a screw. There are terminal blocks that use one screw to clamp two wires placed in parallel at once.

Another very convenient option involves fixing the wires not with a screw, but with a special lever. The terminal blocks are manufactured in such a way that they do not require additional insulation. It is impossible to touch live parts. Their degree of protection is high and equal to IP20. Another line of protection is the plastic housing of the junction box.

Connecting wires with terminal blocks

To connect several conductors (as many as you like), it is easier to work with a terminal block. This is a copper strip with holes and screw clamps. Such structures can be mounted in several units in distribution cabinets. With this design it is very easy to connect the wires in the junction box. This design is especially good for rigid conductors. But the terminal blocks must be firmly fixed in the junction box so that they do not touch each other.

How to connect wires during mixed installation, when they are hidden in wall grooves and behind plasterboard structures with built-in lamps? A flexible wire is used for such light sources. In this case, the quality of the connection of flexible wires should be treated especially carefully.

Junction box options

Wiring, disconnection is the connection of wires in order to distribute current flows. Twisting wires with their further desoldering, welding or without it, is desoldering. Connecting wires or cable cores to terminals and connectors is a disconnection.

Metal boxes must be grounded. These boxes are used only when laying electrical cables in metal pipes, for example, in wooden houses.

Connection of wires in the box

For ease of control of connections, they are made in junction boxes. Any craftsman knows how to connect the wires in a box. Typically, terminal blocks are located inside the distribution box. Box models are available with different numbers of inlet and outlet holes. The size of the box is selected according to the number of wires and their cross-section. Above in the text there are recommendations for choosing the method of connecting the wires. They are all equal and have their own advantages and disadvantages.

For example, a method such as soldering takes too much time to connect even two wires. Instant connection is provided by spring terminals. They are good for everyone: compact, reliable, but they are intended only for single-wire conductors (there are models for multi-wire conductors, but they are used to connect one rigid wire with one flexible one) and for a strictly defined number of them (it is impossible to make another branch when all the places are occupied ).

The wires in the box are connected according to their purpose: phase, common and ground. For installation, a three-core or two-core cable is used, in which the cores are marked with different insulation colors. As a rule, the purpose of the wires is tied to their color: phase - white, common - blue (blue), ground - yellow-green. In any case, how to connect 2 wires (by color) is decided by the master in a specific situation. The main thing is that he understands the issue well.

How to connect aluminum wires

You need to know that aluminum is not only fragile and can break after several bends, but also softens from the slight heating of the contacts when current flows, and flows out from under the screw. In this case, the pressure weakens significantly, and the temperature rises even more.

The ideal rule for an installer: assembled today, tightened tomorrow, and again a week later. In the future, another check with a tightening is arranged every six months. This is the answer to the question of how to connect aluminum wires. But it is advisable to inspect screw connections and copper wires at least once every two years. The wires in the junction box must be connected so that they are accessible for repair or inspection. These rules exist to avoid electric shock to people and eliminate the possibility of fire. Violations of them increase the likelihood of accidents, which can lead to death.

Headphone problem

How to connect headphone wires if they are broken? How to solve the problem correctly so that it is accurate and quality is not compromised? The wiring here is very thin. Simply twisting them together will ruin the quality of the perceived sound. Solder? But to do this, you need to get rid of the varnish that covers the wiring. It is necessary to remove it, but the wires are very thin and it is not easy to strip them with a knife - they break.

So, which wire connection method should you choose? Each method has its pros and cons. Each of the masters knows how to connect the wires correctly, and does it in a way that is more convenient, familiar and easier for him. There will be no problems if the work is done efficiently and conscientiously. It is not for nothing that it is believed that the safety of electrical wiring in the house depends on the decision of how to connect the wires correctly. Therefore, it would be useful to think through all the options and repeat again.

So how do you connect the wires? We take four-hundred-grit sandpaper, drip rosin onto it, place one wire at a time on the rosin, and with a soldering iron and solder we begin to carefully remove the varnish from the wire. After running it two or three times, we will see that it has come off and the wiring has become loose. Then we do the same with the rest of the wiring. That's it, the ends of the wires are prepared, they can be soldered, connecting to each other according to color.

How to connect a single-core and stranded wire so that this does not lead to problems in the future, and the contact connection serves us for many years? And in general, how to properly connect different types of wires?

We will try to answer all these questions in our article, and we will also analyze what such rules are associated with and what dangers are hidden behind an incorrect connection.

First of all, let's look at what the requirements for high-quality contact connections are related to. It is not without reason that clause 2.1.21 of the PUE separately stipulates methods for connecting wires, and allows only screw or bolt clamps, crimping, welding or soldering.

• This is primarily due to the fact that these types of connections can provide the required level of durability and reliability of the connection. After all, any electrician will tell you that more than 90% of all damage occurs at contact connections, and that is why so much attention is paid to them.
• After all, what is a poor-quality contact connection is a connection that has a high contact resistance. And since we have resistance, this means heating.

• As we remember from the physics course, any conductor in a heated state has greater resistance than a conductor with a lower temperature. Therefore, an avalanche-like process results. A poor-quality contact connection causes the conductor to heat up and its resistance increases even more. As a result, it heats up even more until it reaches the point where it simply melts.
• As a result, our main task is to ensure minimum resistance between the two conductors being connected. This is achieved by ensuring the proper area of ​​contact between the two conductors, as well as by ensuring the maximum possible contact between them.
• Let's immediately look at why we will not consider the question of how to twist single-core wires or their multi-core counterparts. Indeed, with the right approach, and through twisting, it is possible to ensure a sufficient area of ​​contact and compression of the conductors with each other.

• The fact is that in any case, the contact connection will be subject to temperature influences. That is, it will heat up and cool down. And as we know, heating leads to expansion of materials, and cooling, accordingly, to contraction. As a result, our contact connection, which is not fixed by any third element, can quickly become of insufficient quality.

Note! Surely each of you can give dozens and hundreds of examples where twisting has lasted for decades, and even now looks better than screw or bolt connections. But, as they say, exceptions to the rule only confirm the rule itself. According to statistics, twisted joints are damaged much more often than other types of joints.

Correct connection of conductors

Now we can talk about how to correctly connect a single-core and stranded wire, two single-core or two stranded wires. And also, which type of connection for each of these types will be optimal, and which should be used only with certain restrictions.

Connection using the compression method

By compression method, PUE means screw or bolt connection of conductors. The same type of connection includes the now popular Wago terminals, which use the compression method through the use of springs or special mechanisms.

• At the moment, the compression method is one of the most popular joining methods. After all, the price of terminals based on this method is one of the lowest. The installation process is simple and does not require additional equipment, and the method itself is quite reliable.

• For wires of small cross-section, the screw connection method is mainly used - or the compression method using a special mechanism. The essence of the screw method is that two conductors are installed in a brass tube, which are then each clamped with its own screw.
• This method is well suited for connecting two single-core copper conductors. If aluminum is used, then this material is softer, and when clamping it with a screw, you can either critically reduce its cross-section or completely crush it. Therefore, for aluminum wires, the use of this method is undesirable, or it should be used with extreme caution.

In the photo - a tip for a stranded wire

• Using a screw clamp to connect multi-core wires is also associated with the possibility of breaking individual wires that make up the conductor in whole or in part during the process of tightening the screw. To protect the wires from mechanical influences, special tips should be used.
• Using special lugs, stranded wires can be connected both to each other and between single-core wires using screw terminals.

• There are screw terminals with a special clamping pad, which provides clamping over the entire cross-section of the brass tube. In this case, the use of special lugs for stranded wires is not necessary.

• As for Wago terminals and the like. There is still debate among electricians about their reliability and durability. Some argue that using springs in terminals is not the best option, others that it is very convenient and the springs are quite reliable.

Content:

Connecting wires is most likely the most common task in electrical engineering. Since for one reason or another there is a lack of length of conductors in electrical circuits, it is necessary to connect their parts together. Obviously, this creates contact, which is the root of many electrical problems. And it is not the electrical connections at a specific location on the conductors that are implied in this case.

If the contact is made correctly, the electrical circuit will function properly. But, nevertheless, the phrase “electrical engineering is the science of contacts” has long sounded like a byword. Later in the article we will talk about how to correctly connect the wires so that this connection does not create problems for as long as possible. As well as a number of other issues that are essential for twisting wires and covering other types of their connections.

Twisting, which the PUE is silent about

In addition to the frequently mentioned words about contacts, among electrical workers there is another common phrase that the work performed by electricians and miners is often very similar in its lethal consequences. In particular, for this reason there is a PUE - essentially, a set of laws for everything that has to do with electrical networks. Let's take an interest in the Electrical Installation Rules about how the wires should be connected.

On the one hand, everything is clearly stated:

• crimping;
• welding;
• soldering;
• squeezes -

and these are the four officially acceptable ways to connect the ends of conductors. But they all require something additional from tools or equipment, and in some cases quite complex, because:

• for crimping you will need a special tool that matches the conductors being connected;
• welding is impossible without a welding machine;
• for soldering, you must have a soldering iron, as well as the suitability of the material of the connected cores for soldering;
• clamps require the use of a special electrical wire connector designed for this purpose.

However, to ensure the connection of electrical wires, you can simply twist their wires together, thus obtaining electrical contact. And, despite the fact that twisting is not specified in the PUE, the compressible reliable connection of the wires itself, especially if approved in the prescribed manner, fully complies with the letter of the electrical law of the PUE.

In order for the wires to be twisted reliably, the following conditions must be met:

• the length of twisted conductor strands from the edge of the insulation to the ends is 40–50 mm;
• electrical wires, or rather their contacting conductors, are cleaned with fine-grained emery or a file in order to remove oxide films or insulation residues. You can also use a knife. In this case, movements must be made along the vein. After stripping, it is recommended to evaluate the quality of film removal using a magnifying glass. This will create the best electrical connection;
• In order to properly connect wires without soldering, the twisted ends of the wires must be formed using one of the generally accepted methods. They should be pressed against each other as tightly as possible anywhere in the twist.
• The types of twists used are shown below. These images will help our readers understand how to properly twist.

What is wrong with twisted wire connections and why is it not explicitly mentioned in the PUE? After all, other methods of connecting wires are noticeably inferior to it in ease of installation and minimal cost, for which such a connection of two wires with one core, as well as twisting multi-core wires, is ahead of all. Other methods of connecting electrical wires remain far behind it.

• The main disadvantage of twisting is its weakening over time as a result of repeated thermal expansion of the conductors.

Gradually, due to temperature deformations of the cores, the force pressing them together weakens, and the contact resistance increases. For electrical circuit wires containing low-power consumers such as energy-saving and LED lamps, weakening the contact force will not be dangerous. But for twisting wires in a circuit with electric heating devices with a power of several kilowatts, from a certain moment an avalanche-like process of deterioration of contact between the twisted conductors can begin. Moreover, if such a wiring connection is not noticed in a timely manner, in the best case, either copper wires or aluminum wires, the cores of which are twisted, near it will suffer from damage to the insulation due to high temperature.

• For this reason, the use of twisting in areas with increased fire hazard is prohibited. In these rooms it is necessary to use a more reliable connection of wires.
• Twisting of copper wires with aluminum conductors is not permitted. Just as in any other connection, direct contact between the copper and aluminum cores is not allowed in twisting due to the occurrence of electrochemical processes leading to rapid deterioration of the connection and increased fire hazard.
• It is not recommended to reconnect two wires that have been twisted. Only straight strands are twisted after stripping the insulation, and straightening usually breaks even the strands of a stranded conductor.
• Correct twisting can only be achieved for relatively thin conductors. It is not recommended to twist thick single-core wires. To connect wires to each other with a significant thickness of wires, it is better to use crimping them with a sleeve.

Starting from a certain core diameter, it is not possible to twist the wires at all. An example would be a power cable. Therefore, twisting of a cable containing 2, 3 or more cores is done with thin copper wire as a preparation for a “clean” connection. Then each pair of fixed wires is soldered.

Twisting is half the battle

However, the experiment, which was carried out with twisted stranded conductors, showed the high quality of contact of all wire connections immediately after installation was completed. A hundred twists of sections of stranded copper wire with a cross-section typical for ordinary apartment wiring showed very low contact resistance, which is confirmed by the images below.

Consequently, after twisting, you do about half of the installation work of connecting two conductors. It still remains to refine the resulting connection so that it does not deteriorate over time. And to do this, you need to either create a force that compresses the twisted wires from the outside, or use one of the methods of merging the wires. Merging of conductors is, of course, the best way to ensure minimum resistance at the junction of two, three or more conductors.

The connection of wires by merging the cores is done either by melting them or by soldering them. In any of these options, the lowest value of contact resistance is achieved. But these methods also have significant drawbacks. Both during welding and soldering, the conductors are heated to a temperature that is dangerous for the insulation.

• In order not to spoil it, it is better to hold the twist with pliers immediately behind the edge of the insulation to dissipate heat during welding or soldering and for some time after completion.
• Although there is technology for welding and soldering aluminum conductors, it is still better to deal with copper. But before soldering or welding, the copper core is also cleaned of foreign deposits and degreased.

Welding and soldering eliminates the very concept of contact at the end of the twist, making in this place either a body in the form of a drop (when welding), or filling all the cracks with solder. When connecting wires intended for powerful electrical appliances, welding and soldering are the most correct way to connect conductors. However, the experiment, which was carried out on hundreds of twists already shown, did not demonstrate a significant decrease in contact resistance. This is evidenced by the images shown below.

The images provide clear evidence of the same joint properties between conventional and welded stranded wires. But with increasing thickness of the cores, as well as for thick single-core wires, soldering and welding will have an advantage over twisting. If the wires can be connected by twisting, and there is no powerful electrical equipment connected to them, it makes no sense to solder them, much less weld them.

Detachable connections

The experiments discussed above testify in favor of mechanical fixation of twists. For this purpose, along with sleeves, there are special PPE caps. They make it possible to splice wires, compressing the twist and maintaining the compression force. These are two types of compressions mentioned in the PUE. The first is the sleeve, and the second is the cap. It is screwed all the way onto the stripped conductors. The device, as well as possible types of PPE caps, are shown in the images below.

The abbreviation SIZ reads as:

C – connecting;

I – insulating;

Z – clamp.

Number 1 (SIZ-1) indicates a cap with grooves, and 2 (SIZ-2) indicates the same part with protrusions. Numbers separated by a hyphen indicate the range of wire cross-sections connected to the PPE. The cap is very convenient in that with its use, not only good conductivity of the connection is achieved, but also the ability to separate it. If you need to choose how to connect the conductors to each other, PPE is the best option for home and office electrical networks.

A quick and convenient device that complements separable types of conductor connections is a terminal block. However, its convenience is limited by the load current characteristics. In comparison with the PPE cap, which improves contact resistance, the terminal block worsens it. And it’s very noticeable. To obtain relevant data, a third experiment was made, information about which is shown below. The welded twists were cut off. The ends of the wires are inserted into the terminal blocks.

• The contact resistance of the terminal block is an order of magnitude greater than that of the twist.

But it is not only the most acceptable solution for connecting low-current electrical wiring in an apartment and office.

• The terminal block is a connecting element between wires with copper and aluminum conductors.
• It is convenient to use for connecting wires with different cross sections.
• For copper conductors, it is recommended to apply contact paste before inserting them into the terminal block.
• Aluminum conductors must be cleaned of oxide film before inserting into the terminal block.

Three types of these connectors are used:

In order for the wire to be inserted into the terminal block without effort and, if necessary, just as easily removed from it, a design with a lever is used, which creates a force in the connection to fix the core. WAGO terminal blocks and their analogs are made on this principle.

A very common type of compression is the screw connection. The designs of many terminal blocks, connecting blocks and sleeves are based on this connection. The screw connection allows you to obtain the greatest force compressing the connected cores. But in order to ensure that such a connection does not weaken over time due to vibrations and temperature deformations, a force is applied to it using a spring, which creates a holding voltage.

• Screw clamps are the most effective connection of a single-core wire with a stranded wire, wires of different diameters, including aluminum and copper.
• Since screws, nuts and washers are always available to everyone who has connected their profession or hobby with technology and works with their own hands, if necessary, connecting two wires with their help will not be difficult. However, this is done according to the rules that are illustrated in the image below.

• When using screw clamps, it is necessary to remember that the quality of contact is primarily determined by the area of ​​the contacting surfaces. And it decreases as the core diameter increases. In this case, no efforts of screw clamps will help. For large core diameters, contact pastes and gels must be used. But in this case, soldering and welding will still provide more reliable contact than a screw connection.

Correct connection of wires is the key to safe operation of the electrical network. We must not forget how to twist correctly, choose the optimal type of connection, and also perform it correctly.