One of the main difficulties that arise in the process of installing electrical wiring with your own hands is the need to connect the wires in the junction box for electrical wiring. In order to prevent common mistakes, and, as a result, malfunctions of switches or sockets, we will consider each stage of independent work.

Almost everyone, one way or another, has an idea of \u200b\u200bwhat a junction box looks like. But not everyone knows why it is really needed, and how it works. Consider the general data that we know about this element.

Junction boxes differ depending on their shape as well as the specific application. Some of them are rectangular and some are round. This setting has no effect on functionality.

As for the features of the application, here they distinguish:

junction boxes for concealed wiring;
junction boxes for open wiring.

They differ from each other in the way of fastening, in some features of the device, and in some cases in size. In any case, they have one single purpose - the distribution of wires from the shield to separately located points of energy consumption, for example, switches, lamps, sockets. At the same time, the distribution of electricity must be uniform in order to avoid interruptions in the operation of devices.

To achieve this goal, the electrical wiring is divided into separate highways or so-called groups. Separate wires are laid in each room, which will power the appliances with electricity, ensuring their operation. It is at this stage that junction boxes appear. They are installed at the nodal points where the wires are interconnected.

It is necessary to buy a junction box for electrical wiring, first of all, for reasons of fire safety. Since it is at the junctions of the wires that the risk of a fire is greatest. If the contact is broken, the resistance increases, and the connection begins to heat up. In some cases, this may cause a fire.

Outdoor electrical distribution boxes serve as an insulating layer between a potential fire source and surrounding objects. In addition, they also have a significant aesthetic role, hiding not always beautiful wire connections from the eyes.

Is it possible to do without mounting junction boxes

Some argue that the presence of junction boxes in the house is not necessary at all. But in fact, in order to do without them, it is necessary to lay a separate wire from the shield to each place of electricity consumption. To do this, you will need to make a lot of sufficiently deep and wide strobes in the wall to lay the wires in them in several rows. All this will entail additional costs of finance and effort.

If, when refusing to use junction boxes, we are guided by the fact that the laying of individual wires generally excludes the presence of connections in the electrical wiring, and therefore is safer, then there is a good answer from specialists. Wiring, carried out in accordance with all standards and the wiring diagram in the junction box, does not pose a danger. In any case, you can always seek help from specialists.

Junction box: dimensions and prices

Each installation junction box has a number of its characteristics, among which size and price play a special role. Consider the three most popular options that are customary to install in residential buildings:

Junction box 100x100x50 mm IP54.
Junction box IP65 88x88x53 mm.

The first option is one of the most accessible and at the same time common. For example, a Tyco junction box can be purchased for just 50 rubles. Its low cost is due to domestic production, as well as the minimum configuration (body and cover).

The second option also has a minimum cost - 46 rubles. It is made from propylene and PVD. Of course, it cannot be said that he will ever be able to compete with metal junction boxes, but he more than fulfills his function of protecting wires from precipitation and wind.

The third option, German-made, will cost you a little more, about 211 rubles. At the same time, the characteristics and dimensions of the junction box are not much different from the first two options. However, according to the manufacturer Hensel, the plastic used to make their products is of very high quality and meets all the requirements for electrical wiring elements.

Of course, all these are quite simple and cheap options. Electrical junction boxes with terminals will cost many times more. But even here we can say that their price is justified by the simplicity of connecting the wires and their further maintenance.

Useful advice! If you don't want to skimp on safety, then you should consider purchasing an explosion-proof junction box.

Terminals occupy a special place in the arrangement of electrical wiring. Installation of this type of junction box is the most simple and does not require special skills. The bottom line is that the box is already equipped with special clamps that are designed to connect wires. Compared to conventional ones, such junction boxes have a number of advantages:

installation and dismantling of conductors is carried out many times faster, while there is no need to use any additional tools;
thanks to the use of a special paste, you can connect wires from different materials, for example, copper and aluminum;
a special wire placement system helps to maintain order in the box, which reduces the risk of a short circuit to zero;
the special design makes it easy to measure the current without having to remove the insulating materials from the wires and does not affect the integrity of the system at all.

For open wiring, junction boxes of this type have become the most popular option. After all, the absence of the need to independently twist and connect the wires made the use of the terminals very convenient. There are many different options on the market today, including an explosion-proof terminal box.

Connecting wires in a junction box for electrical wiring in various ways

It is generally accepted that good contact is the result of the correct connection of the wires to each other. If the work was done with insufficient quality, it will immediately become noticeable due to poor contact or its complete absence. In addition, problems can arise at the moment when you plug in some fairly powerful device.

All this, of course, causes a lot of discomfort. And it is much easier to take care of this in advance, even at the stage of wiring, than to try to solve this problem after a while. Consider the most popular ways to connect wires to each other:

twisting wires in a junction box;
crimping;
welding;
spike;
use of contact screw clamps;
bolted connections;
self-clamps.

All these methods are quite simple to implement and do not require special skills. Let's look at each of them in more detail to get an idea of how best to connect the wires in the junction box.

How to properly connect the wires in the junction box

In order to independently carry out all the work correctly, you should take into account only one main requirement that applies to the installation of junction boxes: it is necessary to provide free access to all wire connections. This is necessary in case of a malfunction of one of the sockets or the switch.

Note! If during the initial installation the junction box is hidden behind the finishing coating, then at the first malfunction it will have to be completely removed in order to carry out repairs.

It is far from always that the problem may be hiding there, but it will never be superfluous to check for contact. Therefore, think over everything in advance in such a way that any repair work can be carried out as easily and quickly as possible. In this case, the connection of wires in the junction box can be performed in any way convenient for you, which will be discussed below.

Connection of wires in a junction box by twisting and crimping

Almost everyone knows how to twist the cleaned ends of the wires. However, when it comes to connecting wires in a junction box, it is worth remembering normative documents that shed light on this issue.

Twisting is considered an unreliable connection option, since the contact area is very small, and it is impossible to count on full contact between the wires. In addition, over time, even this small contact tends to weaken, which makes it impossible to use powerful devices that put a serious load on the system.

A much more reliable way is considered to be crimping, for which a special connecting sleeve is used. The main parameter of its choice is the thickness of all the wires that will be placed in it. The material of manufacture can be either copper or aluminum, and the choice depends on what material the wires themselves are made of.

In order to ensure fixation, a special tool is used, with which the sleeve is compressed. This can only be done with press tongs. Use for this is absolutely not recommended. Otherwise, this technology fully complies with all norms and requirements stipulated by regulatory documentation.

Here is how the wires are connected in this way:

insulation is stripped from the wires, taking into account the required length, that is, the length of the sleeve used;
the stripped ends of the wires are twisted and inserted into the sleeve;
using press tongs, the sleeve is crimped;
with the help of electrical tape or the junction is isolated.

How to connect wires in a junction box using welding

This method is considered to be very reliable, since the result of the work is a single whole wire, which is practically not amenable to oxidation. By fusing the wires together, you get a reliable contact that will not weaken over time. However, the implementation this method a little more difficult than the previous one, because you will need welding equipment and the ability to handle it.

List of tools that are necessary for wire welding work:

welding machine with a power of at least 1 kW and rated for 24 W;
carbon electrode;
rosin or flux, which will further protect the metal part of the wires from oxidation;
personal protective equipment: welding goggles and gloves.

If you have at least minimal skills in working with a welding machine, as well as all of the above components, the further stages of work will not be particularly difficult for you. The insulation is cleaned from the wires, and their inside is cleaned with sandpaper to a shine.

Then twist the wires traditional way and pour the flux into the recess of the electrode. Press the wires against it and hold until you see the appearance of a ball, the so-called contact point. After that, the process of connecting the wires can be considered complete. It remains only to clean the junction of excess flux, varnish and insulate.

Connecting wires in a junction box by soldering

At first glance, this method is similar to the welding method, but it has a significant difference. To solder the wires together, solder is used, melted with a soldering iron. This is a permitted method that provides reliable connection. Its only drawback is that it is not very reliable in places where the wires are subject to strong heat.

Note! If you do not know how to solder, then this method is better not to use. The connection can turn out to be too fragile, and with the slightest mechanical load or tension, the wires can simply break at the soldering point.

In order to solder the wires you will need:

soldering iron;
tin-lead solder;
rosin or flux;
in the case of using flux - a special brush for it;
fine sandpaper.

For the most part, the process of connecting wires is the same as in the case of welding. But it’s not the metal itself that melts, but only the solder. In this case, you need to carefully monitor that the molten solder must flow inside the twist for a more reliable bond. For the most part, this method is used to work with copper wires, however, provided that special solder is available, the same can be done with aluminum.

Use of screw terminals and bolted connections

The use of screw terminals is a fairly common method used by many due to its simplicity and convenience. However, it also has its drawbacks, which are useful to know about before starting work.

Initially, screw clamps were used to connect different metals together that should not touch. For example, it could be copper and aluminum, which, in the presence of moisture, begin to interact with each other. Over time, this method began to be used for connecting wires. And it was even fixed at the level of regulatory documentation.

Note! When using this method on aluminum wires, be aware that they will require periodic crimping to ensure that contact is not lost or weakened over time.

Bolted connections are also quite often used to connect wires, however, if it comes to hiding them after that in a junction box, then this method can be considered inappropriate. It's all about the bulkiness of the connections.

In order to connect the wires in this way, a steel washer must be inserted between them. This happens in the following sequence: a washer is put on the bolt, then one of the wires is put on, and then another washer. This is followed by a second wire and a nut that tightens the system. Of course, all this also requires good insulation, so the volume of the connection is decent.

Useful advice! This method has its advantages - it is well suited for joining different metals, since a special paste can be placed inside to prevent oxidation processes.

Installation of a junction box for electrical wiring

Having figured out how the wires can be fastened together, let's consider how to install the system itself using the example of an IP55 junction box for outdoor installation 100x100x50 mm.

Most often, installation is carried out in a blank wall of brick or concrete. This can cause certain difficulties in the process of drilling a niche for it, but the system will be securely fixed. If the box has round holes, then special drill bits can be used. For rectangular or square, use a grinder with a special diamond blade designed to work with concrete.

After the niche is ready, be sure to try on the junction box to make sure everything is prepared correctly. Junction box must be completely placed in the wall so that after installation its front surface is at the same level with the wall.

Some junction boxes have special plugs that are specifically designed to run the cable in these places. They must be carefully broken or cut, while maintaining the integrity of the overall structure. The ends of the wiring are wound in them according to the scheme.

When you are sure that all the wires have been brought into the junction box, you can start preparing the mortar to fix it. The fixing principle is very simple:

a certain amount of mortar is placed in the niche prepared for the junction box with a spatula;
the box with the cables already installed is pressed inward as deeply as possible;
excess solution that protrudes on the sides is removed;
if necessary, the box can be held by hand for the first few minutes to allow the mortar to set a little.

Useful advice! Alabaster can be used instead of mortar. It dries much faster and still holds the weight of the box just as well.

Both in working with the installation of a junction box for open wiring, and in the case when it comes to a closed system, high-quality installation largely determines the life and quality of electrical wiring. The main thing in working with electricity is to correctly assess your capabilities and, if necessary, seek help from professional electricians.

In order to provide every corner of an apartment or office with electricity, you cannot do without a junction box. Modern junction boxes are very diverse both in shape and in the materials from which they are made. They are surface mounted and internal.

The purpose of such devices is to route the wires in the right direction to the points of consumption or disconnection - these can be switches, sockets or lighting fixtures. It will not be a hassle for a professional electrician to separate the wires in a junction box, but for a novice electrician it can turn out to be a real science. Today, WAGO universal terminals are increasingly used for contact connections in the junction box.

We observe the colors of the wires in the junction box

In order to cope with the installation, you need to connect your imagination: wires are “pipes”, and electric current is “water”. There is a “water supply” through the phase wires, but a “return” flows through the neutral conductor, while the protective conductor serves just in case of an emergency: if “water” leaks somewhere, it will certainly be “drained” into the ground. It is very convenient that they are modern. The most common color looks like this: White color- phase (L), blue - zero (N), yellow-green - ground (PE).

During wiring, it is very important to follow the sequence in the colors of the wires, which will greatly facilitate their breeding in the junction box. Before proceeding with electrical work, you need to clearly determine the installation of lighting points, sockets and switches, i.e. draw up a diagram to install junction boxes in convenient places, and preventive and repair work can be carried out in the future.

Be sure to read detailed articles about wiring:

Junction box installation procedure

Many make repairs using stretch or suspended ceilings, so the wiring must be laid so that it does not end up in the drilling area when the guides are mounted, and care must also be taken to ensure that the junction boxes remain in the access area. If the junction box is left behind a false ceiling, a small hatch can be installed.

The last word of electrical engineering says this: from the switchboard you need to lay a wire for lighting - 3x1.5, for sockets - 3x2.5 wire. Therefore, in the junction box there may be enough a large number of wires to connect. In order not to get confused, they must be labeled.

Scheme in the junction box, two lamps

Scheme in the junction box, two lamps and a group of sockets

Wiring diagram for lighting and sockets

One of the stages of electrical work is the connection of wires in junction boxes, which follows immediately after laying the cables. According to the Electrical Installation Rules (PUE), electrical wire connections should only be made in junction boxes.

Today, there are many ways to connect wires in a junction box. The choice of connection type depends on the following factors: core material - copper, steel or aluminum; working conditions - on the street or in the apartment; number of conductors - two, three, four; the cross section of the cores is the same or different. Based on these factors, the most appropriate and correct method is selected.

Why do you need a junction box

Quite often there is some neglect of the junction box (junction box). Some people think that using it when laying wires is a waste of time. After all, it still needs to be fixed on the surface, and this is additional effort. It is much easier, for example, to twist the conductors, insulate the junction and “roll up” everything with plaster.

During operation, free access to the wire connections must be provided. For example, if there is no light in some room or the socket does not work? The test showed that the reason is the lack of voltage. How to find a junction box in an apartment or a faulty section of the circuit? Breaking wallpaper, breaking plaster to get access to the twisted wires?
If in the future you need, for example, put an additional one (two, three). Connect them "in parallel" from the first? But is it always convenient? While connecting new wires in the junction box will not be difficult;
The correct connection of the wires is using terminal connectors. What depth do you need to hollow out the “channel” in the wall in order to hide the terminal block there?
In terms of fire safety, the advantage of such a box is undeniable.

Wire connection methods

Special Electrical Installation Rules (PEU) regulate the correct connection of electrical conductors by welding, soldering, crimping or using screw and bolt clamps.
The rules do not stipulate the most common connection method - twisting. Although a properly performed twist is more reliable than a bad solder connection.

joined materials. It can be aluminum, copper, or a combination;
the number of cores in the connection. You can connect not only two, but also three, four or more wires;
section and number of cores.

Wire twisting

To make such a connection, you need to strip the ends of the cores, carefully twist them with pliers and insulate the place of twisting. Very simple and cost-free. But such a connection weakens over time due to the residual elastic deformation of the material, which means that the resistance in the connection increases and the contact begins to heat up until destruction and ignition.

Therefore, in no case should wiring be laid with twisting on combustible substrates, for example, in wooden house. And one more prohibition - weak protection against moisture does not allow such a connection to be made in rooms with high humidity. In this way, it is strictly forbidden to connect dissimilar materials, multi-core cables with single-core cables and at a current of more than 3 A.

In order for the twist to be of high quality, it is necessary to remove the insulation from the wires up to 80 mm, fold them perpendicular to each other if there are two of them, and in parallel if there are three or more, and twist tightly. The remaining ends of the wires must be removed with wire cutters with a helical movement, as if smearing the material of the wires one into the other.

The total length of the finished twist should be at least ten, and preferably fifteen core diameters. If special caps or a heat-shrinkable tube (cambric) are used for insulation, then they are put on the wire before twisting.

It is recommended to put on the heat shrink tube twice, and lay the insulating tape in at least three layers. Whatever insulating material is chosen, it must also capture the wires' own insulation to protect it from moisture and its slipping.

Soldering wires

This method is the best in terms of manufacturability and reliability, but requires some skills to make a quality connection. Before soldering, the wires must be thoroughly cleaned of insulation and oxides, irradiated if necessary and twisted not as tightly as with simple twisting, coated with flux and soldered.

By soldering, you can connect both copper, and with some skill, and aluminum wires, with a suitable flux and solder. Do not use an active acid flux, as it destroys the connection, remaining on the bare wires. The junction is isolated in the usual way. The junction box in this case is called the junction box.

the need for skills in work, the complexity of the process;
use of a special tool;
one-piece connection, that is, for repair it must be completely removed;
an increase in resistance over time in the connection, which worsens electrical conductivity and increases voltage losses in the network.

wire welding

Welding is an even more reliable connection method than soldering, but it requires a welding machine with personal protective equipment and welding skills, which is much less common in everyday life. Unless you need to independently perform electrical work in a country house, then the purchase of an inverter-type welding machine will be economically justified.

Welding inverters are small-sized, have a wide range of welding current regulation, and provide stable arc burning with low power consumption. For welding copper wires, carbon-copper electrodes or carbon rods from conventional AA batteries are used.

The preparation for welding differs only in the density of the twist and in that the free ends of the two strands, even if there are more of them in the connection, are straightened and pressed parallel to each other to facilitate the formation of a ball of melt. Then the twist is placed in a welding clamp (ordinary old pliers) and the ends of the wire are welded with a carbon electrode to the main twist for two to three seconds so that the insulation does not melt. After cooling, the welding site is isolated in the usual way.

Often there is a temptation not to wait for natural cooling, but to use cold water to speed up the wiring process. But cold water causes the appearance of microcracks in the material, which naturally affects the quality of the connection.

Wire crimping

With this connection method electrical wires special tubular sleeves or tips are used. The industry produces sleeves for wires from 2.5 to 240 mm², and it is very important to choose the right electrical wires for each connection.

A special tool is required to perform the work. It can be a swaging press or tongs, mechanical, electrical or hydraulic. Having chosen a suitable sleeve and adjusted the tool, the insulation is removed from the wires, the ends are cleaned and quartz-vaseline paste is applied to them, the connector is put on and crimped.

If the tool is simple, then you need to perform several compressions at some distance from each other. Using a good tool, you can crimp the sleeve in one go. At the end, the usual isolation of the junction is performed.

The wires to be connected can be inserted into the connector from opposite sides so that their joint is located approximately in the middle of the sleeve. It can be convenient to insert both wires on the same side, while the total cross-sectional area of all wires should be less than the cross-section of the sleeve. High-quality installation and reliable insulation are the positive aspects of using crimping.

the sleeve is deformed during crimping and its reuse is impossible;
the need for a special tool for crimping the sleeve, fitting it in length and stripping the insulation from the conductor;
for crimping the connection of copper and aluminum wire, a rather rare special sleeve is needed;
quite a lot of time for the installation of electrical wiring.

With clips (PPE)

The clamp is a cap with a square steel wire coiled into a spiral cone. For aluminum wires, the cone is filled with a special paste that prevents oxidation of the bare ends. The information on the package with clamps will allow you to choose the right size of PPE in accordance with the cross-sectional area and the number of connected conductors.

To connect the wires, their ends are stripped to a distance slightly less than the depth of the cap, put together, twisted slightly and the cap is screwed on top. It is not necessary to strip bare wires from oxides, since this work is performed by the edges of the spring, and its turns tightly press the cable cores to each other.

The use of such connectors is technologically advanced, they not only connect the wires, but also isolate the junction, however, they do not provide the contact area, as when twisting with soldering. The bright colors of the caps help to mark zero, phase and ground during installation if the wires do not have.

gradual weakening of the spring over time, and, consequently, an increase in contact resistance and voltage losses in the network;
restrictions on the number of connected wires, you can connect two with a cross section of 4 mm² or four with a cross section of 1.5 mm²;
impossibility of mixed connections.

Bolt connection is simple, reliable and effective method. You just need to have a short bolt with a small section, three washers and a nut. True, it takes a lot of electrical tape for such a connection, and it is not used in the junction box because of its bulkiness. A washer is put on the bolt, then a stripped wire is wound, another washer (if copper and aluminum are connected), a second wire, a washer and the nut is tightly tightened.

Screw terminals

Screw terminals allow fast and clean installation. They are widely used when connecting to the wires of lamps, switches, sockets. With their help, it is possible, without the need to isolate the connections.

the need for crimping or soldering a multi-core cable before installation;
the need for periodic maintenance of the connections, since the screws need to be tightened, that is, they need access.

Clamp "nut"

Such a connector is named for its shape. It is a cable clamp with special plates in which the grooves for the wires are made, and four screws in the corners. The wires are stripped, inserted under the plate and fixed with screws. Then a carbolite shell is put on.

With this clamp, you can connect copper and aluminum, the insulation is quite reliable, the installation process is simple and easy. Basically, such a branch connection is used to drain to apartments from a common aluminum riser. But besides tightening the threaded connections, there is another drawback - the dimensions, due to which the “nut” does not fit into the junction box.

Connection using terminal blocks is used in junction boxes, when installing lamps, sockets and switches. Terminal blocks are small in size, easy to fit in a box. A brass bushing is inserted into a small plastic case, into which screws are screwed on both sides.

Stripped conductors are inserted from the ends of the block and clamped with screws with force. For wires of different sections, pads with different inlets are designed.

connection of only two wires;
the poor quality of the pads themselves, due to which disturbances in the network are possible;
care is needed when mounting aluminum and stranded wires so as not to damage the contact due to the brittleness of the metal.

Connection terminals WAGO

This relatively new type of connection using insulated spring clips (connectors) is by far the most reliable and safe. Disputes over the reliability of connections using Wago terminals can be associated either with fakes on the market, or with the wrong choice of terminal for a specific load.

International certificates and approvals protect the reputation of these products. Their only drawback is their high cost. The special screwless spring mechanism makes the installation of connections simple and fast. for connecting wires can be reusable with a special lever that clamps the wire and releases it if necessary.

Wago terminal blocks how to use? Disposable terminals fix the core with some effort, but, according to the manufacturers, it is impossible to release it. For installation, you only need to strip the ends of the wires and insert them into the clamp.

the possibility of mounting dissimilar metals;
the possibility of fixing more than two wires at the same time;
neat fixation of thin wires;
good connection quality;
compact dimensions.

Detailed connection diagram

During the operation of the wiring, malfunctions may occur - for example, an open circuit has occurred. In the event that during the electrical installation, the workers did without a switchgear. boxes, and the joints were simply rolled up with a finishing material such as plaster, then in order to get to the joints again, you will have to break the exterior finish - tear off the wallpaper, break the plaster layer, etc.

It is unlikely that anyone will be satisfied with such prospects. If in the future you need to install additional sockets, then in such cases it is not always convenient to run wires from sockets already installed earlier, it is easier to connect directly to the box.

If the wires are connected using terminal blocks, then a channel of a sufficiently large depth will have to be punched in the wall, which is much more labor-intensive than a simple connection in a junction box.

Finally, from a fire safety point of view, the advantage of using junction boxes is undeniable. For the proper organization of electrical work, there are special Rules for the Construction of Electrical Installations (PUE), which also regulate the procedure for connecting electrical wires.

One of the very important steps in the installation of electrical wiring is the connection of wires in junction boxes. It is very important to make the connection in the junction box secure, as subsequently, access to it may be difficult, especially since in some modern houses the junction boxes are completely plastered.

There are several different ways to connect wires: ordinary twisting with a layer of electrical tape (or heat shrink), twisting with welding ends, twisting with PPE (spring tip), connection using Wago clips.

Which of these methods is better, the debate has been going on for a long time. Many cite various documents and regulations, which say that the connections must be made by welding. However, this rule is true for aluminum wires, which are now practically not used anywhere. For copper, the reliability of welding is somewhat questionable, although it is still better than ordinary twisting with electrical tape.

If you still decide to connect the wires using a twist with electrical tape, then it is better to use a heat shrink tube, and already wrap it with a small layer of electrical tape. The most optimal, in my opinion, is the connection using PPE (connecting insulating clamp) or Wago.

What we see after plastering the walls:

We take out the cables and clean the box. We cut the cables with a margin and make them the same length. I do about 70-90 mm if measured from the wall.

We remove the insulation from the cable.

We clean the wires. The length of the bare section of copper I have is about 30-40 mm

Then we twist. It is convenient to do this with pliers. We bite off the ends a little.

We wrap a layer of electrical tape over the PPE, I use black cloth electrical tape.

Then carefully stuff everything into the box. After filling, the box will need to be closed with a lid.

Below are photos of the connection using Wago clamps.

We expose the wires, the length of the exposed copper section should be about 8-10mm.

We put the wires in the clamps and snap them into place. We make sure that the clamp holds the conductors well.

Then, carefully stuff everything into the box.

Connection Creation Mechanism

Making electrical wiring at home is easy. To do this, you need to have the necessary knowledge and equipment. The equipment is purchased in the store, knowledge does not even need to be bought. At the very beginning, a power grid diagram should be drawn up. In most cases, the building owner hires an electrician who does not represent the future location of the furniture and as a result, the switches are closed by doors, sockets in the corners are covered by furniture.

calculate the load on the power grid;
cross section of wires;
divide consumers into groups.

lighting;
power part, that is, sockets.

It is best that these two circuits are mounted with separate power cables. If you plan to install powerful electrical appliances: electric stove, oven, boiler - these devices must have their own separate circuit, i.e. separate switch, fuse and cables.

Connection of wires in a junction box according to PUE

PUE is a collection of regulatory documentation for the device and installation electrical circuits, in fact, this is the desktop Bible of all people who begin to engage in electrics. The collection shows the basic principles of creating circuits, the rules for their calculation, protection and communication devices. Further, the entire description of electrical devices will be in accordance with the rules according to the PUE.

The choice of section and brand of wire

For laying electrical wiring in rooms and connecting wires in a junction box according to the PUE, the cores must have a different color insulating coating, from the same manufacturer with the same color scheme. For wiring, it is best to use a wire of the VVGNG brand - single-core copper, flat in double insulation, best of all with the additional designation NG, which means non-combustible.

It is best to purchase a cable from a well-known manufacturer, which must have a certificate. There is no need to take an unmarked wire, the wiring in the house is first of all safety and is done for more than one year, so saving is inappropriate here. It should be borne in mind that a copper cable with the same cross section can withstand one and a half times more load than aluminum.

Attention! for a capital scheme, you cannot use a multi-core cable PVS or ShVVP. Although these wires are soft and more convenient to lay, they have more current resistance, so they will heat up more when the load is connected.

Power calculation

One of the basic rules for calculating the cable: used in the calculation of 1 sq. mm - 9 A. electric current, that is, a cable with a cross section of 1 mm can withstand the load of a kettle or iron with a power of 2 kW.

lighting lived in 1.5 mm square, which corresponds to 10 - 12A .;
sockets in rooms 16A, which corresponds to a cross section of 2.5 mm. sq.
kitchen electric ovens, the wire for which must withstand 25A. is a 4mm section. kv;
the core of a four-burner electric stove must withstand 32A. - section 6 mm2.

Choosing the right email connection wires in the junction box depends on its cross section.
Attention! it is impossible to use an electric cable from different manufacturers, since they have different specific (ohmic) resistance per 1 linear meter.

Electrical junction box and wire connection

After laying the wires, according to the drawn up scheme, they must be connected to each other. In order for the connection to be in one place, there are communication boxes (junction boxes). Depending on the installation, the connections of the device can be round or square, deep or smaller and are divided into internal (for hidden wiring) and external according to the method of attachment.

According to the requirements of the PUE, the electrical cable must run at least 15 cm from the ceiling, taking into account all canopies. At the same distance, a device for switching cable cores is also attached. To install the inner box, a niche is drilled in the wall, corresponding to the outer diameter of the sleeve; for the outer box, it is mounted directly on the wall.

How many wires can be twisted in a junction box? You should not save on junction boxes and try to get as many wires as possible there - it will be inconvenient to connect, and all of them may not enter. As a rule, 3-4 wires are brought into one junction box.

Basic wiring diagrams

When disconnecting in a junction box, knowing how to connect the wires to is not all. It is necessary to figure out which conductors to connect.

How to connect sockets

How to run an outlet from a junction box? As a rule, the socket group is a separate line. In this case, everything is clear: you have three cables with three (or two) conductors in your box. In this case, usually brown is the phase wire, blue is zero (neutral), and yellow-green is ground.

In another standard, the colors may be red, black and blue. In this case, the phase is red, blue is neutral, green is ground. In any case, the wires are assembled by color: all of the same color in one group.

How to unplug the junction box. The wires brought into the junction box are folded, pulled out, cut off so that they are the same length. Do not cut short, leave a margin of at least 10 cm so that you can remake the connection if necessary. Then the conductors are connected by the chosen method.

If only two wires are used (there is no grounding in the houses of the old building), everything is exactly the same, only there are two connections: phase and neutral. By the way, if they are the same color, first find the phase (with a probe or multimeter) and mark it, at least by winding a piece of electrical tape around the insulation.

With a switch, the matter is more complicated. There are also three groups, but their connection is different.

input - from another junction box or from a shield;
from a chandelier;
from the switch.

How should the circuit work? Power - "phase" - goes to the switch key. From its exit is fed to the chandelier. In this case, the chandelier will only light when the switch contacts are closed (position "on"). This type of connection is shown in the photo below.

Connecting a single-gang switch in a junction box

If you look carefully, this is how it turns out: the phase with a light wire enters the switch. It leaves from another contact, but already blue (do not mix it up) and connects to the phase wire that goes to the chandelier. Neutral (blue) and ground (if mains) are twisted directly.

Testing wire connections in junction boxes

After all connections are made, the exposed sections of the conductors are insulated with heat shrink tubing, and the wires are laid in junction boxes. The boxes themselves are left open until testing of the installed wiring. First, the connected lines are energized by turning on the appropriate circuit breakers.

If, after switching on, nothing sparked anywhere and the machine did not knock out from a short circuit due to erroneous connection of wires or poor-quality insulation of connections, the electrical wiring is tested with load current (loading), which is carried out by connecting various electrical appliances to the mounted lines. It is recommended to load each line with the maximum allowable current.

The download should take some time (preferably several hours). During this period, possible defects in electrical installation will have time to manifest themselves. A visual inspection of the connections in the junction boxes should be made - signs of high temperature will be visible by melting the insulation or terminal blocks. It is also important that there is no characteristic smell of overheated or burnt insulation.

After removing the voltage, check all connections by touch - they should not be hot. If, when loading the electric cables with the maximum rated current for several hours, no remarks were found regarding the operation of the connections, then the electrical installation is considered normal, the junction boxes can be closed and the wiring put into operation.

Cables and wires in residential and non-residential buildings are laid from a shield with an electricity consumption meter, fuse plugs or circuit breakers under the floor, along the walls to junction boxes, where they are connected by twisting or using terminal blocks (electric clamps).

From distribution boxes, electrical wiring is laid to other soldering or junction boxes, which are connected to one machine or the same group and to switches, sockets, and lamps. Disconnection is possible without special education and experience as an electrician, it is enough to follow this instruction.

Usually 3-4 groups come to the apartment (including a separate group coming to the electric stove, which is laid with independent cables or wires). Thus, in case of damage on the line, only part of the building or apartment is disconnected from the power supply. Pay special attention to the proportional and even distribution of the load between the circuit breakers or safety plugs in the electrical panel.

Before starting work, it is necessary to de-energize the line on which the work will be carried out by unscrewing the plugs or turning off the machine.

As a rule, one junction box is installed for each room; in case of a significant distance between the outlets, an additional one can be installed, specifically for the outlets.

Junction box installation step by step guide

Learn more about choosing a connection method and video editing features

Junction box wiring diagram

All protective or grounding (marked as PE in the diagram, highlighted in yellow) and zero conductors (marked N in the figure, marked in blue) are interconnected by color, as shown in the diagram. There will be no ground conductor if the wiring is two-wire.

Phase conductors (highlighted in black and red) are a little more difficult to disconnect, if the wiring goes from the junction box only to the sockets, then the phases are also connected to each other.

In the case when the wiring goes to a luminaire with a single-gang switch (as shown in the figure), connect the wire that departs from the switch to the phase going to the luminaire (in Figure L to lighting), and connect the phase coming to the switch to all phase wires (in the diagram L on the switch). There should be 4 connections.

When distributing conductors to a luminaire with a two-gang switch, a four-wire cable is laid before it (2 phase on conductors, 1 phase off, 1 zero, 1 “ground”). In the case of two-wire wiring, it is three-wire, since there is no ground conductor. Connect the phase conductors going to the sockets. They also connect the phases of the supply cable that come to the common terminal of the two-gang switch, 2 wires from which go to the lamp lamps separately. Below are the wiring diagrams for a two-gang switch without ground.

All zero and ground conductors (if any) are connected together. There should be 5 connections inside the box (including the connection of the ground wires). Below is a wiring diagram for a two-gang switch with “ground”.

Content:

All work carried out in the field of electrical engineering requires a careful and balanced approach. Each operation must be carried out in strict accordance with the technology. Therefore, quite often, for novice electricians, the question arises of how to connect the wires in the junction box.

Purpose and types of junction boxes

In an apartment or a private house, the distribution of electrical networks begins with a shield installed at the entrance. However, as practice shows, in each room additional distribution of wires is required, due to the presence of several connection points, mainly switches and sockets. All lines drawn to these points are connected in junction boxes. Thus, in addition to a reliable connection, free access to wires and cables is provided for performing various operations.

Depending on the type of installation, junction boxes can be outdoor or indoor, intended for flush mounting. In the second case, a hole is prepared in the wall according to the size of the junction box. After installation, the box cover will be in the same plane with the wall surface. The outer box is fixed to the wall surface and covered with finishing materials, such as plasterboard.

Junction boxes are usually round or rectangular in shape. They are equipped with four leads, and in some designs there may be more. Each outlet has a thread or fitting for more convenient or plastic pipes where the wires fit. In the future, this greatly facilitates the replacement of a damaged cable. It is easily disconnected in the box, and then - from the switch or socket and pulled out through the pipe. In the same way, a new wire is laid in its place.

Wiring diagram in the junction box

Methods for connecting wires in junction boxes

The connection of cables and wires in junction boxes can be done in different ways. Most in a simple way, although not completely reliable, is considered normal twisting. Due to weak and unreliable contact, overheating and short circuit of the wires can occur. This method is recommended to be used temporarily, for example, in order to check how the assembled circuit works. However, even for temporary use, it is recommended to follow certain twisting rules.

For stranded wires, the insulation is stripped by about 4 cm. The wires are separated from each other by a distance of about 2 cm. The connection is made to the junction of unseparated wires. The conductors are first twisted with your fingers, and then the twist should be securely tightened with pliers and insulated with tape or heat shrink tubing. Connecting single-core wires is much easier to perform. They are twisted together for the entire length of the area cleared of insulation.

For twists, special mounting caps are often used. They provide a more reliable connection, high-quality contact and insulation. Each cap consists of two parts: outer - plastic and inner, with a metal part in the form of a cone, inside of which there is a thread. This connection allows you to increase the contact area and is great for two or more wires. The twisting process itself is very simple. It is necessary to remove the insulation by about 2 cm and slightly twist the ends to be connected. Then you need to put a cap on the twist and turn it with force several times so that the wires get inside. The dimensions of the caps are selected in accordance with the cross section and the number of conductors to be connected.

Soldering is considered one of the most reliable methods. Before connecting the wires, it is necessary to tin with rosin or a special soldering flux. Then the conductors are twisted, the tin is taken on a heated soldering iron and the twist is heated until the molten metal flows between the turns. The connection is completely enveloped, thanks to which a quality contact is established.

If available, the wire connection can be made by welding over the entire twist. If the cross section of the core is 1.5 mm2, a current of 30A is required, with a cross section of 2.5 mm2 - 50A. Copper conductors are welded with graphite electrodes. The ground is carefully connected to the top of the twist, and the electrode is brought to the bottom. After a short touch, an arc appears, producing instant welding. The junction must cool down, after which it must be insulated.

When connecting the wires in the junction box, we must not forget about the terminal blocks. They can be screw or clip-on. The required number of conductors is inserted into a certain place, after which they are securely connected with screws.