How to connect wires in a junction box. Reliable ways to connect electrical wires. Prices for sockets with grounding

Knowledge of modern technologies and methods of working with electrical fittings, is it really necessary? Yes, you need to know how to connect electrical wires correctly.

This can be useful during installation and installation of any power supply systems. Is the wiring burned out, does the lighting fixture need to be replaced, or new equipment needs to be installed. Such knowledge may not be necessary, but it would be better to know all the common methods of connecting electrical wires

Application in terminal block circuits

Terminal blocks are electrical products made of non-conducting material, inside of which a conductive sleeve is inserted, which has a pair of screws at opposite ends. They serve to secure the wire. An excellent choice for implementing a modern way of connecting wires.

When choosing a reliable connection of wires, it is important to remember: terminal blocks are produced with different holes for many cross-sections.

This method is almost always used for connections in junction boxes of any type, during installation, installation of wall and other lamps. It is suitable for. It is easy to mount a network using such fittings; you just need to insert the bare ends into the holes and, using moderate force, securely tighten the screws. The wire itself should not be crushed. Having figured out how to properly connect electrical wires using terminals, it is worth exploring other equally reliable methods.

Terminal method rating: Excellent fastening quality. Their prices are reasonable. Quite quick and easy installation. A good opportunity to connect different conductors, for example, aluminum and copper.

It is not recommended to connect aluminum and stranded circuits with blocks. This is due to the high fragility of aluminum wires and the great flexibility of the stranded wire conductors themselves. But overall a decent method.

Spring terminals

Quick installation of electrical networks is sometimes simply necessary. For example, install temporary lighting on a balcony, terrace, gazebo. Wago spring terminals are an excellent product for such work. A modern and of course reliable way to connect wires. Although they are new to the electrical accessories market, installation using spring terminals is quick and, importantly, convenient.

The main difference between the use of the Vago terminal blocks themselves: they are more convenient to connect any wires in electrical boxes than with twisting. Here, for high-quality installation, a unique clamping mechanism is used, rather than a simple screw. Manufacturers produce both disposable and reusable vagon systems.

In the usual version, this product is used for one-time use; during repair work in the future it cannot be restored. It is removed and a new one is installed in its place.
Wago reusable terminals are a little more expensive, but with their help you can disconnect the assembled contacts several times, rewiring the circuit to suit your needs. This speeds up the process of repairing or installing permanent and temporary networks. A simple lever-type mechanism provides the advantage that it is possible to carefully but efficiently fix any wire without damaging or squeezing it.

With the help of a vault, it’s easy to do the fastening yourself; you just need to strip the insulation and insert the required wires into the mounting hole. Press the lever. It's important to get it right.

Wago Clamp System Rating: A unique opportunity to combine any aluminum, copper and other conductors. There is an option for connecting multi-core cables simultaneously (two or more).

Wago universal clamps allow you to fix any thin stranded conductor without damaging it. Another plus is the compact size of the pads.

Wago self-clamping terminals

Excellent quality and durability. The Vago type block has a technological hole that provides access for a screwdriver with a voltage indicator. The operation of any power line can be checked at any time. Perhaps one drawback is the considerable cost of the terminals themselves. But this type of wire connection is the most modern and fastest.

Isolation with PPE caps

Deciphering the product is not difficult, connecting insulating clips (PPE). They are ordinary nylon or plastic caps with an internal lock.

The simplest type of connection of wires, it is carried out after twisting the conductors themselves, the cores. Caps are often used to connect wires in junction boxes and to mark connections with the desired color.

Evaluation of the use of such products: Quite low cost of PPE. The use of safe material prevents ignition of electrical wiring. Easy installation, put it on a twist of wires and you're done. These caps have a wide range of colors, which is convenient. Of course, if the wires are not color coded, colored PPE has the ability to determine or simply mark zero, phase and other necessary electrical routes.

There are also disadvantages: Insufficient level of fixation. Multicore wires can be installed only after soldering.

Installation of networks using sleeves

This option claims to be the most reliable connection method. Any load and quality of wires.

Crimping wires with sleeves

The conductive wires are inserted into a special tube - a sleeve, and crimped with a certain force. There is one thing, but. The cross-section of the wires should not exceed the cross-section of the mounted sleeves. Having inserted and crimped the clip, the sleeve is carefully insulated with heat-shrinkable tubing or other insulating materials.

Overall rating. A great way to securely connect wires. The direction of the conductors can be on different sides of the tube or on one side. The sleeves are quite inexpensive. A good way to reliably connect wires to each other.

There are also disadvantages. Disposable use of sleeves, they are not dismountable. To carry out such work you will need a tool: pressing pliers, which are also used as a special tool. They remove the insulation. They have a crimping device in their arsenal, and electrical installation work takes a little longer.

Soldering or welding wires

This method is reliable. Typically, this method of connection in a junction box involves first stripping and twisting the ends, after which they are dipped into heated solder. It is advisable to connect aluminum to aluminum wires by soldering. They are then insulated using a heat pipe or insulating tape.

Evaluation of the soldering method. It gives strong chain contacts and excellent quality, not expensive, it is the most reliable method of connecting electrical wires in a soldered box.

Technological disadvantage. You can't do this without a soldering iron. The speed of work is not high. The connection is naturally not detachable. It follows from this that soldering is done in extreme cases, using more modern connection methods. It has not been popular among masters for a long time because it takes more time.

There is also a less common method for connecting electrical wires, welding. The process is similar, but requires the use of a special welding machine, of course, and certain skills.

Contact twisting method

Not a new, one might say “old-fashioned” method, it consists of spiral twisting of the cores among themselves. The essence of all work is to twist the stripped conductors using pliers, and cover the twisted area with insulation. These are, perhaps, all the ways to twist wires.

Evaluation of this connection method. High speed of all installation work. The cost part is minimal.

Flaw. It is prohibited to connect together strands of different compositions, copper and aluminum wires., oxidation is inevitable. According to the regulatory framework, fastening wires with twists in a junction box is not recommended for use in rooms with flammable materials, high humidity, basements, or in any house built of wood. More details about the twisting method. I definitely recommend watching a video about which is better: twisting or Vago terminal blocks.

Wire clamp "walnut"

Such a device is simply a cable clamp that has two plates inside and several screws for tightening, usually in the corners. It is enough to screw the wires to the plate itself. Then put a carbolite shell on top.

Grade. An excellent option for connecting any electrical wires in a large and medium-sized junction box. Definitely, these types of products are quite convenient and have a high degree of protection. Makes it possible to quickly connect a wire to a thick gauge track without tearing it.

Flaws. Dimensions allow installation only in spacious distribution boxes and switchboards. Over time, the screws loosen.

Tip: When choosing fittings and method, remember the following:

It is necessary to work only with isolated tools and use protective equipment.
Be sure to post a “do not turn on” warning sign on the shutdown panel or meter.
Connect electrical appliances according to the attached instructions.

Having considered the main types of wire connections, you can easily select the right option. And having a simple tool and a diagram at hand, you can mount it yourself. In details

Installation of a distribution box in an apartment is an important stage of electrical wiring; thanks to it, the electric current is evenly distributed to points that consume electricity (lamps, sockets, switches). A properly installed box ensures 100% uninterrupted use of electrical wiring. In appearance, the junction box is a metal or plastic structure with holes on the sides. Wires extend from the box, which provide current to all important electrical devices.

To distribute electricity evenly, the wiring is divided into separate groups of consumers. In rooms, distribution boxes are installed at the wiring connections.

Distribution boxes perform several important functions in residential premises:

ensuring fire safety;
creating an aesthetic appearance in the apartment.

The wires are located inside the box; thanks to the housing, they are not subject to mechanical stress, which ensures their safety.

According to the installation principle, the boxes are built-in and external. Built-in ones are installed in specially prepared recesses in the wall, and overhead ones are fixed on the wall surface.

Main function of distribution box

Distribution The box allows you to reduce wire costs. If it weren't for it, each electricity consuming device would be connected with a separate cable. No box provides an increase in the channels for laying wires, and visually this looks unaesthetic.

The advantage of using junction boxes is undeniable, and proper connection of wires will ensure the safety of the premises. This device isolates contact points from the effects of flammable wall materials.

The ease of use of the junction box ensures ease of repair. The main function of the box is that it ensures uniform distribution of electricity to the locations of the main consumers. In addition, such designs of switching boxes involve adding new branches of electrical networks to the existing wire if necessary.

Types of distribution boxes

Distribution boxes according to the type of fastening are divided into:

overheads, which are installed outside on the wall;
internal, installed in the prepared wall recess.

The main purpose of the junction box is to provide easy access to the electrician in the event of a system malfunction. For convenience and to preserve the integrity of the wires, the box is closed with a lid. To carry out any manipulations with the electrical wiring, specialists just need to remove the cover and get acquainted with the causes of the problems.

Distribution boxes are made from the following materials:

Plastic.
Metal.

Metal cases are made of tinned steel sheets or aluminum alloys. The main requirement for materials is that they are not subject to corrosive changes.

If a distribution box is needed for strategically important facilities, then it must be selected with the following characteristics:

screw cap;
waterproofing gaskets.

The metal case has universal properties and perfectly protects the wiring during a fire, that is, during a fire, the metal structure is able to preserve the contents of the box for some time, during which it is possible to de-energize the network.

The plastic case also has positive properties: resistance to oxidative processes and the ability to isolate electric current.

Distribution boxes vary in geometric shape and are:

round;
square;
rectangular.

If a small number of wires are supplied to the box, then a round box configuration can be used. In cases of a large number of wires, it is better to use a rectangular distribution structure.

Important! If the walls are concrete, then it is easier and more convenient to install round box structures.

The dimensions of distribution boxes depend on the number of wires and their cross-section.

Internal structure of distribution box

The design of the junction box consists of a housing and a cover, as well as side inlet holes.

The internal cavity of the box is equipped with terminals and clamps for fastening wires. Typically, the input cable is secured using terminals, and separate wires are secured using clamps. If the box is not equipped with terminals, the wires are secured together by twisting.

The disadvantage of a terminal connection is that after use the bolts can become loose and disrupt the wiring contact. Loose contact causes heating and subsequently burning of the wires. Twisting is considered a more reliable method.

It should be taken into account that the connection of aluminum and copper wires in the junction box leads to destruction of the connection and the occurrence of an electrochemical process.

Important! Brass terminals provide high-quality connection of aluminum and copper wires.

Installation Rules

Electricity distribution boxes are mounted approximately 25 centimeters from the ceiling. In cases where the distribution box is installed in a hidden way, the cover must be on the surface so that it can be easily opened and work carried out.

When choosing a place to install the box in a hidden way, you need to ensure access to it while respecting the design intent of the interior of the apartment.

Installation

In concrete or brick construction, electrical appliances are placed in the wall cavity in specially prepared holes in the wall. Such recesses are made with a hammer drill; in cases of a round design of the distribution panel, the holes are made with a special crown. In the seat, the box is attached to the wall using alabaster mortar, which guarantees a strong connection between the housing and the wall.

After determining the installation location of the box, you need to prepare the wire network and make the connection. In order to bring them to the switching box, you need to prepare grooves into which the wires will be laid. If the walls allow the possibility of wiring in a horizontal position, then the gaps between the walls and the ceiling are quite useful for this.

After preparing the channels and socket boxes, the wiring of the switching box wiring system is carried out.

Important ! To ensure the correct connection of the wires in the junction box for the purpose of quickly carrying out subsequent repair work, the wires are marked.

The input cable from the electrical panel is designated as “input”; the wire from the sockets should also be marked, because labeled wires will not allow mistakes during maintenance and repair. In order for the wires to be used correctly, the cross-section must be strictly observed; for example, to supply electricity from the panel, a two or three-core cable with a cross-section of 4 square millimeters is used.

Such a cable guarantees full use of any high-power consumer. For the lighting system, a cross-section of 2.5 square millimeters is used, and for sockets - 1.5 square mm.

After familiarizing yourself with all the nuances, they begin to install the junction box. The basic principle of installing the switching structure is indicated by precise adherence to the sequence of wiring connections. The wiring diagram in the distribution box includes the following parameters: phase is connected to phase, zero is connected to zero, and grounding is connected to grounding.

Laying of wires occurs subject to compliance with all parameters and requirements of the drawn up connection diagram. The wires are laid inside the box, preferably with an allowance of about 10 centimeters. When connecting wires, it is necessary to strip the ends of insulation and secure them in the terminals.

If there are no fasteners, you can simply fix the connections by twisting. This method involves twisting the wires at the points of contact; this method is often used and is considered reliable. After this, the joints are fixed with insulating material (insulating tape or plastic caps).

Important! The wires are mounted in pipes made of metal or plastic, which provide insulation from external negative factors.

Various modifications of switching devices are widely presented in specialized electrical stores. The included instructions indicate the main characteristics and current voltage ratings.

Connection principles

For quick connection and to avoid confusion, the wires are marked with colors of different shades. The following color combination is considered popular: white indicates phase, blue indicates zero, and light green symbolizes grounding. When connecting, strict compliance and consistency must be observed.

Like any other work, electrical wiring in a junction box also begins with a design. To draw up a competent electrical wiring diagram, you need to determine the exact location of electrical installation points - lamps, sockets, switches. In accordance with the diagram, distribution boxes are placed in convenient places. Providing access is necessary in case of interruptions in the electricity supply.

The rules for electrical installations stipulate that wires must be connected by soldering, welding or using clamps. However, the “old-fashioned” method of twisting wires has proven itself among the people; this method ensures the manufacturability and reliability of the system.

Sometimes twisting the wires is not enough; to ensure reliability, the contact area is treated with soldering. After connecting, the wires are insulated and placed in the box body so that they do not come into contact with each other.

After carrying out the entire complex of work, diagnostics are carried out; for this, the most powerful electrical appliance in the apartment is connected to the network and the wires are checked for the presence of heating. If you find any wire heating up, this means that it does not have enough contact area, and in such cases you should probably replace the wire with a larger cross-section wire.

Conclusion

All types of work with electricity are strictly related to the installation of a junction box. Such a device is an important link in the electrical network, and proper installation ensures that the facility is fully supplied with electricity.

Experts recommend installing boxes in every room, because they connect all the wires from sockets, lamps and switches. In cases of electrical problems, it is quite easy to determine the location of the breakdown and thereby carry out repairs quickly and without damage to other premises.

The above information will serve as instructions for the correct installation of the junction box.

In a field such as electricity, all work must be carried out strictly, accurately and without a single mistake. Some people want to figure out such work on their own, not trusting third parties to carry out a responsible mission. Today we will talk about how to properly connect wires in a junction box. The work must be done efficiently, because not only the performance of electrical appliances in the house, but also the fire safety of the premises depends on it.

About the distribution box

In an apartment or house, wires from the electrical panel are routed to different rooms. There are usually several connection points: switch, sockets, and so on. In order for all the wires to be collected in one place, distribution boxes were created. They carry wiring from sockets, switches and are connected in a hollow housing.

So that during repairs you do not have to look for where the wires are hidden in the walls, electrical wiring is laid on the basis of special rules prescribed in the PUE (Electrical Installation Rules).

Distribution boxes are classified according to the type of fastening. So, there are boxes for external installation and internal installation. For the second option, you need to prepare a hole in the wall into which the box will be inserted. As a result, the box lid is located flush with the wall. Often the cover is hidden with wallpaper or plastic during repairs. As a last resort, an outer box is used, which is attached directly to the wall.

There are round or rectangular junction boxes. In any case, there will be at least 4 exits. Each outlet has a fitting or thread to which a corrugated tube is attached. This is done to quickly replace the wire. The old wire is pulled out and new wiring is laid. It is not recommended to lay the cable in a groove on the wall. If the electrical wiring burns out, you will have to dig into the wall and disturb the finish in order to carry out repair work.

What are distribution boxes for?

There are many factors that speak in favor of the existence of junction boxes:

The power system can be repaired in a matter of hours. All connections are accessible, you can easily find the area where the wires have burned out. If the cable was laid in special channels (corrugated tube, for example), then the failed cable can be replaced in an hour;
Connections can be inspected at any time. As a rule, wiring problems occur at the connection points. If the socket or switch does not work, but there is voltage in the network, first check the quality of the connection in the junction box;
the highest level of fire safety is created. It is believed that dangerous places are connections. Using a box will keep them in one place.
minimal time and financial costs when repairing wiring. There is no need to look for broken wires in the walls.

Connecting the wires in the box

There are several ways in which conductor connections can be made in junction boxes. Note that there are simple and complex methods, however, if executed correctly, all options will ensure the reliability of the electrical wiring.

Method number 1. Twisting method

It is believed that the twisting method is used by amateurs. At the same time, this is one of the most reliable and proven options. PUE do not recommend using twisting, since the contact between the wires is unreliable. As a result, the conductors may overheat, putting the room at risk of fire. However, twisting can be used as a temporary measure, for example, when testing an assembled circuit.

Method No. 2. Mounting caps - PPE

Very often, special caps are used for twisting conductors. As a result, it is possible to obtain a reliable connection with good contact. The outer shell of the cap is plastic (the material is not flammable), and inside there is a metal part with a cone-shaped thread. The insert increases the contact surface, improving the electrical parameters of twisting. Most often, thick conductors are connected using caps (no soldering required).

It is necessary to remove the insulation from the wire by 2 centimeters, slightly twist the wires. When the cap is put on, it must be turned with force. At this point the connection can be considered ready.

Before making the connection, you need to count the number of wires. Based on the data obtained (cross-section), a specific type of cap is selected. The advantages of twisting using plastic caps are that you do not need to spend a lot of time, as with conventional twisting. In addition, the connection is compact.

Method No. 3. Connecting conductors by soldering

If you have a soldering iron on your household and you know how to work with it, then the wires can be connected by soldering. Before connecting the wires, they need to be tinned. Soldering flux or rosin is applied to the conductor. Next, the heated tip of the soldering iron is immersed in rosin and passed along the wire several times. A reddish coating should appear.

After the rosin dries, the wires are twisted. Using a soldering iron, tin is taken and the twist is heated until tin flows between the turns. The end result is a high-quality connection with excellent contact. However, electricians are not very fond of using this connection method. The fact is that it takes a lot of time to prepare. However, if you are doing the work for yourself, you should not spare any effort or time.

Method number 4. Welding cores

Using an inverter welding machine, you can connect wires. Welding is used over twisting. You need to set the welding current parameters on the inverter. There are certain standards for different connections:

- conductor with a cross section of 1.5 sq. mm - 30 A;

- conductor with a cross section of 2.5 sq. mm - 50A.

If the conductor is copper, then a graphite electrode is used for welding. The grounding from the welding machine is connected to the upper part of the resulting twist. An electrode is brought from below the twist and an arc is ignited. The electrode is applied to the twist for a couple of seconds. After some time, the connection will cool down, then it can be insulated.

Read also: Hidden electrical wiring in a wooden house

Method No. 5. Terminal blocks

Another option for connecting conductors in a box is using terminal blocks. There are several types of pads: screw, with clamps, but the principle of the device is identical. The most common is a block with a copper plate for attaching wires. By inserting several wires into a special connector, they can be reliably connected. Installation using a clamp terminal makes the connection very simple.

In screw terminals, the terminal blocks are placed in a plastic housing. There are open and closed types of pads. Closed pads are a new generation invention. To make a connection, wires are inserted into the socket and clamped with a screw (using a screwdriver).

However, terminal connections have a disadvantage. It lies in the fact that it is inconvenient to connect several conductors together. The contacts are arranged in pairs. And if you need to connect more than three wires, then several branches are squeezed into one socket, which is very difficult. At the same time, such connections make it possible to operate branches with high current consumption.

Another type of terminals is Wago terminals. Today two types of terminals are in demand:

— terminals with a flat-spring mechanism. Sometimes they are called disposable, since it is impossible to reuse the terminals - the quality of the connection deteriorates. Inside the terminal there is a plate with spring petals. As soon as the conductor is inserted (it should only be single-core), the petal is pressed out and the wire is clamped. The conductor cuts into the metal. If you pull out the conductor by force, then the petal will not take its previous shape.

Some terminal connections contain wiring paste inside. This connection is used if you need to connect copper and aluminum wires. The paste protects metals from oxidation, protecting conductors;

- universal terminals with a lever mechanism - this is the best type of connector. The wire, stripped of insulation, is inserted into the terminal and a small lever is clamped. At this point the connection is considered complete. And if you need to reconnect, add contacts, lift the lever and pull out the wire. The pads can be operated at low current (up to 24 A - with a cross-section of 1.5 sq. mm) and at high current (32 A - with a conductor cross-section of 2.5 sq. mm). If wires are connected through which a current higher than that specified will flow, then a different type of connection must be used.

Method number 6. Crimping

The wires in the box can only be connected by crimping using special pliers and a metal sleeve. A sleeve is put on the twist, after which it is clamped with pliers. This method is suitable for connecting conductors with a large load.

Method No. 7. Bolted connection

Connecting multiple wires using bolts is a simple and effective connection method. To complete the work, you need to take a bolt and several washers with a nut.

It is not enough to know how to connect the wires in a junction box. You need to know which conductors are connected to each other. So, a washer is put on the bolt thread. The core is screwed on, the second washer is put on, and then the next core is put on. At the end, put on the third washer and press the connection with a nut. The node is closed with insulation.

There are several advantages of bolted connection of conductors:

- ease of work;

- low cost;

- the ability to connect conductors made of different metals (for example, aluminum and copper).

However, there are also disadvantages:

— fixation of wires is not of high quality;

- to hide the bolt you need to use a lot of insulation;

Content:

Electrical wiring is an integral part of the installation of any electrical network. The electrical network ensures the distribution of electricity. Sections of wires may be under a layer of plaster. But they can be laid in one way or another on the surface of walls and ceilings. In any case, they must be securely connected to each other. For this purpose, distribution boxes are installed in certain places.

Following their installation, the installation of wires is done. First, before connecting consumers, a wire connection diagram is prepared. If you hear such a name as a wiring diagram, it means that we are talking about supplying power to several consumers. Unplugging the junction box does just that. The wiring diagram in the junction box always contains the main power wire.

Distribution boxes are where the wires of sockets, switches and other loads are connected. This is the node where the electrical wiring branches. Electricians coined the word "disconnection" to apply to such branching. It is purely colloquial and is not used in technical literature.

The connection of wires in a round shaped junction box is usually used for hidden electrical wiring. In this case, it is easier to prepare the installation site using an electric drill with a special drilling device.

The shape of the box in relation to the manufacturability of its installation for external wiring is not so important. However, a rectangular box provides more space and may be preferable for this reason. Next, we will tell readers how to connect the wires in the junction box.

Connection methods

Connecting the wires in the box is done in two main ways:

twisting the connected wires (twisting);
using special accessories. These wire connectors in the junction box are called terminal blocks and blocks. All connecting devices make electrical contacts using a screw or elastic clamp.

It is not difficult to twist even several strands of wires inserted into a junction box. Twisting is the simplest fixed contact. But the ease of obtaining results has a bad effect on the quality of this contact. The main disadvantages of simple twisting are the following:

relatively small contact area (especially for large cross-section conductors);
lack of compensation for oxidation and weakening of compression of the contacting conductors.

Therefore, conventional twisting should be used only for minor electrical loads in the range of 100–300 W. Before connecting the wires in the junction box, it is necessary to correctly determine the length of the contact of the wires. If it is impossible to accurately predict the current strength that will pass through the twisting, its quality must be improved in one of the following ways:

cover with solder (solder);

weld the veins.

In addition to welding and soldering, special accessories are often used that fix the contact of the cores. Of these you can

use a crimping cap screwed onto the twisted wires.

The cap is also called a connecting insulating clip - PPE

If it is necessary to install a powerful consumer of electricity, the use of caps and long twists formed with their help is allowed. How this is done is shown in the images below.

Use a sleeve that crimps either twisted or straight wires;

use tips;

connect the wires with a terminal block;

Use terminal blocks of a suitable design.

Comparison of methods

The images provided above clearly demonstrate that the connection of the cores can be done in several ways. Therefore, we will next consider their disadvantages and advantages.

Core connection method	Flaws	Advantages
regular twist	Limited use due to contact instability. For more reliable contact, it is necessary to increase the length of the twisted wires.	Ease of manufacture.
Comments Contact instability appears over time due to temperature deformations of the metal. When the wires are twisted, twisting the wires in insulation also does not hurt. This stabilizes the contact.

soldered twist	The complexity of the process associated with preparing wires for soldering, the need for additional equipment and conditions for its proper operation. The need to cover the connected cores with insulation. It is impossible to connect aluminum and copper conductors.
Comments The surface of the veins is cleaned as best as possible from oxides. The prepared twist is coated with liquid flux. When soldering, you can overheat the core and damage the insulation of some brands of wires. It is best to apply solder by dipping the twist into it. In this case, the wires are held with pliers close to the insulation to remove heat.

welded twist	The complexity of the process associated with the preparation of wires for welding, the need for additional equipment and conditions for its proper operation. The need to cover the connected cores with insulation. It is impossible to connect aluminum and copper conductors. It is impossible to remake a finished connection without a supply of wires along the length.	One of the most reliable types of connection, especially for powerful electricity consumers. Simple visual control of connection and contact quality.
Comments The core is heated to the melting temperature of copper. In order to maintain the integrity of the insulation during welding, it is necessary not only to ensure heat removal, but also to select the optimal length of the core. If stripping the insulation is too short, the necessary heat dissipation cannot be achieved.

cap	Dependence of contact reliability on the quality of the cap. Lack of ability to control contact reliability. Limited application due to an increase in the thickness of the connected cores. It is impossible to connect aluminum and copper conductors.	An effective combination of ease of manufacture and quality of connection. Possibility of dismantling without extra length of wires. You can do without insulating the connection, since the cap performs this function.
Comments The cap contains an internal thread formed by a conical spring or applied to a pressed sleeve. It is screwed onto a twist. In this case, a force arises that pushes the cap apart, but compresses the veins. This is the essence of using the cap. But if this force turns out to be too great, the sleeve will either crack or tear off the core metal. In any case, the force will weaken significantly. This can happen not only during installation, but also during operation due to heating. It is impossible to control the state of the contact, as well as the force when installing the cap. It is necessary to select and install it correctly - in accordance with the recommended wire cross-section.

	Dependence of contact reliability on sleeve deformation. Lack of ability to easily monitor contact reliability. The need to cover the sleeve with insulation. It is impossible to connect aluminum and copper conductors. The need to use an additional tool - crimping pliers. It is impossible to remake a finished connection without a supply of wires along the length. Additional costs for paste to improve contact.	One of the most reliable types of connection, especially for powerful electricity consumers.

Let's assume that you are a bit of an electrician and decide to install or replace the wiring in your own house or apartment yourself. But if you don’t know any other way than to connect the wires in the junction box using simple twisting, we recommend that you familiarize yourself with this material. After all, there are many methods for reliable joining of contacts: welding, soldering, crimping, as well as the use of electrical connectors. Each of the options must be applied correctly and in the right place.

Soldering and welding of wires

Modern requirements set out in regulatory documents (PUE) prohibit splicing electrical wiring by conventional twisting, regardless of the insulation method. But if the twisted wires are soldered or welded, the contact will be reliable and will comply with all the rules.

Let's look at how to connect current-carrying parts of cables in a junction box using desoldering:

Remove the insulation from the wires at a distance of about 3 cm and sand them with fine sandpaper.
Twist the strands tightly together using pliers.
Using rosin and solder (POS 61 brand is suitable), carefully tin the connection so that molten tin flows into the space between the wires.
Insulate the joint with heat shrink tubing or wrap it with adhesive tape.

Note. Soldering copper is not difficult, but oxidized aluminum sometimes has to be treated with acid.

Connecting wires by welding is performed in the same manner, only instead of a soldering iron, a device with a carbon electrode is used. A special recess is made in it, into which flux is poured, after which the device is plugged into the network, and the electrode is pressed against the twist until an influx is formed in the form of a small ball.

The advantage of this method is the durability of the joint and the ability to connect wires of different sections, including multi-core ones, in the junction box. Due to its reliability, the connection is successfully used in power lines with various loads, but it has some disadvantages:

Do not solder or weld copper conductors with aluminum ones;
This connection is permanent and in case of alteration according to a new scheme, the contacting areas have to be bitten off.

Reference. Soldering contacts is often used when installing low-current networks, for example, telephone cables and radio points.

Disconnection by crimping method

In this case, the reliability of the connection of the wires in the junction box is ensured using sleeves made of the same metal as the conductors - aluminum or copper. To complete the job, you will also need special press pliers, shown in the photo.

Note. Some would-be electricians practice crimping sleeves with ordinary pliers, which is unacceptable. Correct fixation of contacts is carried out only with pliers.

Now about how to connect electrical wires in a box in this way:

Perform termination and twisting of wires as described above.
Place a sleeve over the twisted ends (it should be matched to the diameter and fit tightly).
Crimp the sleeve with pliers in two places.
If the distribution boxes are installed outdoors, the connection is insulated with heat shrink, ensuring tightness. PVC insulating tape can be used indoors.

This joining option has the same pros and cons as welding: you can connect wiring of different sections and numbers of wires, but you cannot connect contacts made of dissimilar metals.

Application of connecting terminal blocks

Terminals for quick connection of wires are of 2 types:

screw clamps in the form of blocks;
Wago type self-clamping connectors

The technology for splicing electrical cables using terminal devices is quite simple. The wires need to be exposed only 1 cm and inserted into the clamps. In the first case, the cores are fixed with screws, in the second - with levers or automatic latches. By the way, terminals with latches are disposable, while terminals with levers are used repeatedly.

We list the advantages of screw terminal blocks:

Fast and reliable docking.
Ability to connect copper wiring to aluminum.
Provides a detachable connection.
Does not require additional insulation.

One of the disadvantages of the pads is their size. It happens that when there is a large accumulation of wires coming from several switches or sockets, the screw connector does not fit inside the junction box. Point two: single-core wires are fixed without problems, but multi-core wires are flattened with screws, which is not good. Therefore, it is better to pre-tin such ends.

Wago clamps, which allow you to connect up to 4 wires of the same cross-section, have the same advantages as screw terminals, but take up less space. In this case, the operation of disconnecting the entire junction box will take about 5 minutes, which is very convenient for installing electrical wiring. Judge for yourself: the bare end needs to be inserted into the clamp with pliers until it stops and that’s all.

Reference. Similar devices are often used for laying Internet cables and other low-current networks.

Since there are cheap products on the market from various Chinese manufacturers, self-clamping terminal blocks have acquired a dubious reputation. The fact is that in low-quality connectors, the contact weakens over time, causing them to overheat and melt. If you purchased original Wago products, then there will be no problems; in other cases, it is better not to take risks and connect only lighting wires with clamps (power supply to switches, chandeliers, and so on). Wire the sockets using a different method.

The master will tell you how to use self-clamping terminals correctly in his video:

Plastic PPE caps

The abbreviation SIZ stands for connecting insulating clamp. It is a cone-shaped cap made of plastic, which contains a steel spring with an anodized coating.

The technology for using the product is as follows:

Remove the insulation from the wires to be connected to a distance of 2-3 cm.
Gather the wires into one bundle and insert them into the cap until it stops.
Applying force from the blind part, turn the cap by hand 2-3 turns. A traditional twist is formed inside, secured with a spring.

Such clamps are quick-release and reusable, provided that the spring was not damaged during dismantling. With their help, the connection in the box is made quite quickly, does not require insulation and does not take up much space.

Important point. In order for the PPE cap to provide reliable and durable contact, it must be selected according to the diameter corresponding to the total cross-section of the wires being connected. For the correct selection, use the table:

Details on how to connect wires in a junction box in various ways, including using caps, are described in the video:

Conclusion

Now, knowing the features of all methods of connecting contacts in a junction box, you can choose the best option and successfully apply it. Finally, let us mention another old method of connecting conductors - bolted, when the conductors are bent around the thread to the right side and pressed with a nut. But this option is practically not used due to the inconvenience and cumbersomeness of the connection, although it is considered reliable and complies with the PUE.

Design engineer with more than 8 years of experience in construction.
Graduated from the East Ukrainian National University. Vladimir Dal with a degree in Electronics Industry Equipment in 2011.