Types of junction boxes for electrical wiring. Unplugging junction boxes

One of the most important and responsible work is electrical installation. The quality of their implementation depends not only on the uninterrupted operation of all electrical appliances in the apartment, but also on the safety of housing in general. Such work begins with the installation of electrical installation products. Today we will touch on the issues of the device of socket boxes and junction boxes.

Socket device

The socket box, also known as the installation box, is the basis for mounting sockets and switches.

In accordance with fire safety rules and building codes and regulations, electrical wiring, as well as sockets and switches, can be of two types: open-mounted (on the wall surface) and hidden (directly into the wall). In the event that all the wiring in the apartment is made in an open way (for example, in boxes) or when connecting an additional electrical appliance, external sockets / switches are used.

However, much more often the wiring is carried out in a more aesthetic concealed way (for example, by chiseling the wall), therefore, sockets / switches are also mounted in the wall. With this method of installation, in accordance with SNiPs, it is necessary to use socket boxes.

It is recommended that the installation of socket boxes and open boxes be carried out simultaneously with the laying of electrical cables. In this case, when marking the wiring, the places of the future location of the end points (sockets / switches) and junction stations (junction boxes) are marked.

Installation of socket boxes

We determine the height of the location of the future socket / switch, and, therefore, the installation location of the socket. For the most part, it depends on the overall design project of the room and the designer's intent. One of the placement options in terms of ergonomics is a height of seventy centimeters from the floor. Sockets can also be placed at a height of about thirty centimeters from the floor. If there are small children in the family, wiring accessories are mounted as high as possible. From an aesthetic point of view, they should all be at the same height. For the kitchen, the optimal level is just above the table. Another important rule: a distance of at least half a meter from electrical appliances and gas pipes.
We draw the outline of the future mounting hole of the socket box, attaching it to the wall for the sample. Using a drill or puncher with a "crown" nozzle, we make a hole in the wall. The hole size depends on the wall material. If it is concrete or brick, the diameter should be three millimeters deeper and wider than the box itself. In this case, it will be fixed with alabaster or plaster. If the wall material is drywall, then the hole should be equal to the box. In this case, fastening is carried out using the paws of the socket. Taking into account such a difference in installation, we also select the type of socket - "for plaster" or "for drywall".

Having drilled the contour of the hole with the help of a "crown", we remove the perforator and, using a hammer and a chisel, remove the remains of the stone and trim the bottom. If there is no “crown” nozzle or the shape of the hole should not be round, but square, we use a hammer drill with a diamond nozzle for concrete, a grinder or a drill for concrete.
After the hole for the socket has been prepared, we make a groove - a groove for laying an electrical cable. We deepen the strainer into the hole so that the cable passes freely. In the future, we break out special holes at the bottom of the box, cover with hatches, and insert the cable.
We clean the landing hole from dust, apply a primer. To securely fix the box in a monolithic wall (brick / concrete), we use building gypsum or gypsum glue (knead to the stage of soft plasticine).

We apply a little prepared mixture into the landing hole. Insert the socket and press down with your fingers. A small amount of glue should squeeze out into the holes in the box.
We cover the gap formed between it and the hole with the prepared mixture (gypsum, glue, alabaster) using a spatula. After drying, remove the remaining mixture with a spatula.
After the mixture has completely dried, remove it from the socket, align and grind the outer edges. The socket box is prepared for the installation of a socket or switch.

Junction boxes device

The junction box, also known as the junction box, is the location and protection of the connections of electrical wires and cables.

After installing the socket in the socket, it is necessary to connect the power supply to it. Since it is impractical to run a separate cable from the switchboard to each consumer, they switch from the main wire connected to the junction box. It is in it that the electrical wires going to various consumers are connected. This method is aesthetically neat and safe.

Junction boxes should be installed in easily accessible places - for ease of maintenance. Access to wires must be quick and unhindered. The number of junction boxes in one room is not regulated, but aesthetic characteristics and expediency should be taken into account. The location is usually under the ceiling. In wet rooms - showers, bathrooms - junction boxes are placed on the outer wall, and not inside.

Junction boxes can be both external and internal. And, as well as socket boxes, - under brick / drywall.

Before installing junction boxes, we create a network of wires along which electrical wires and cables from electrical installation products are laid. An important point when laying the wiring: the lines to the sockets / switches are drawn strictly vertically, and the horizontal ones can be located in the niches formed by the wall and the floor slab.
After completing a series of shtrabs and socket boxes, we install the wiring, an important part of which is the junction box device. We attach the overhead junction box to the wall using self-tapping screws / dowels. We mount the hidden box directly into the wall. The installation procedure is similar to the installation of socket boxes in a hidden way. We mount the box in the prepared hole / niche and fix it with alabaster / plaster.

We complete the installation of the junction box, performing the switching of wires and cables. Our task is to connect a lot of wires to the input, i.e. trunk cable containing three wires: "phase", "zero" and "ground". We connect the wires going to the sockets by color: "phase" with "phase", "zero" with "zero", "ground" with "ground", respectively. As for the wires leading to the switch, the principle is different. "Phase" towards the switch, connect to the "phase" of the lighting circuit, "zero" lighting connect to the "zero" of the input.
An important point in terms of safety during installation is the connection of wires. It is performed in two ways: soldering several wires or connecting with terminals. We carefully place the insulated wires in a box and close it, without bricking it up, but leaving the possibility for access.

Installation of electrical wiring in a house, apartment, garage, office, etc., it is always carried out with the installation of distribution (branch) boxes. One minimum is always installed in each room.

From branch boxes, electrical cables or wires diverge to lamps, switches and sockets. They consist of a plastic case with a lid, they are built-in for hidden wiring (in Figure 3 and 4) and overhead for outdoor wiring (in Figure 1 and 2).

Junction boxes made of metal are subject to mandatory grounding and are installed only when laying electrical cables in metal pipes. For example, in wooden houses and buildings according to the rules and requirements.

Branch boxes vary in size and shape. Large boxes should be used in places where a large number of cables or wires will come. In shape, it is better to take round ones than square or rectangular ones, because they will not need to be leveled. And you can use the hole saw to drill a hole in drywall, blocks, bricks, etc.

Before installing the box it is necessary to make strobes and fix cables in them from the place of its installation to sockets, switches and lamps. Or fasten the cables behind drywall or panels that sheath walls or ceilings.

With open wiring the overhead box is attached to the ceiling or wall with 2 self-tapping screws or dowels, just run the electrical cables through special seals. In the seals, it is necessary to cut a hole slightly smaller than the diameter of the cable. The figure shows the version with dust seals. There are waterproof options with rubber seals and screw plugs.

For installation of recessed box it is necessary to knock out or drill a recess into which it is then necessary to smear the box flush. It is much easier to put a box in drywall.

Installation of a junction box in drywall.

After that, we clean the wires and connect them along this one.

How to install a junction box for hidden wiring.

In houses and apartments, all electrical wiring is hidden under plaster or in the channels of panel houses, so the junction box is hidden flush with the wall. For her installation is necessary:

Not round when smearing the box must be ensured that it is fixed exactly in level. This is especially true for rectangular options. Square boxes, even if crookedly pressed in, in most cases allow you to align the lid.

The main difficulty that you may encounter in the process of laying electrical wiring in a private house, apartment or a specific room is the need to switch them inside the junction box.

There are several common mistakes associated with this process, and if you want to avoid them, there are a number of important points to consider. Laying wires in strobes or cable channels is easy. Another thing is the junction box: when working with it, you must follow certain rules and recommendations.

Purpose of splitter boxes

Electrical wiring should be divided into separate groups depending on the consumer of electricity. For these purposes, special electrical products are used that perform important functions:

increasing the level of fire safety;
aesthetics.

Cables are hidden under the box body, which provides reliable protection against mechanical damage and significantly extends the life of the wiring as a whole. If we consider the principle of installation, then the devices are divided into built-in and outdoor, suitable for open wiring. The former are placed inside pre-prepared niches, the latter are attached to the surface of any wall. There is also a special street box.

The main function of the junction box

With the help of this electrical product, you can significantly reduce the cost of organizing electrical wiring. Without this element, each electrical appliance would have to be connected to a separate cable, which would lead to an increase in the number of channels required for installation and ruin the appearance.

Proper distribution of the cable inside the box will increase the safety of residential and non-residential rooms. This is due to the insulation of connection points with combustible materials contained in the wall. The design of the equipment is thought out to the smallest detail, therefore, it guarantees the ease of repair work.

But the main function of the box is related to the uniform distribution of electrical energy between all consumers installed in the room. In addition, the structure of the product takes into account the potential expansion due to the addition of new branches of the electrical circuit.

Why is it called differently

This electrical equipment is called differently, ranging from distribution and ending with a branch or junction box. The principle of operation is always identical: the box is the head center, which receives electrical energy from the source, after which it is distributed to different branches, supplying voltage to sockets, switches and lighting fixtures. That is why it got its name - "distributive". The alternative name "branch" came from the fact that one wire enters the box, and several cables come out.

Soldering products are called so because of the method used for switching wires inside the case: after twisting, they must be soldered. Despite the huge variety of modern methods of switching cables in boxes (terminal blocks, sleeves, clamps, welding), they are still called soldering.

Another synonym for the device was the word "switching". You can hear it only among people employed in the field of electrical installation. In fact, the word is derived from two other terms - distribution and connection: first, the wires are distributed along the branches, and then they are connected. Following this principle, it is easy to guess where the other name of the box came from - “connecting”.

Thus, going to the store for a junction box, you do not need to be surprised if the product you need is on the counter, but under a different name. Also pay attention to the dimensions of the device, according to which you will have to create a recess in the wall. For example, rectangular boxes for an apartment are usually produced in a standard size - 100x100x50 mm.

Is it possible to do without mounting junction boxes

Theoretically, this option is possible and acceptable, but to make sure that it is practically impossible to implement it, it is enough to imagine a simple picture: an introductory electrical panel is installed at the entrance to the apartment, boxes in the rooms are not used, so you have to pull separate cables to each switch, socket and lighting device. This will lead to significant costs for the purchase of a cable, the expansion and deepening of the strobe (or the installation of wider cable channels, which will violate the aesthetics). Conclusion: installing a junction box is a cost-effective and rational solution.

Many people mistakenly believe that an extra junction box appearing inside a junction box (on the line from the inlet shield from a particular outlet) will result in poor security, while a solid cable is much better. In fact, if everything is done correctly and correctly, then the selected switching method will not pose a threat. Finally, this product makes it easier to troubleshoot on the line, so you don't have to gouge through the entire wall to find the damaged section of the electrical circuit.

Types of junction boxes

Above, we indicated the first criterion for classifying boxes - the method of attachment (embedded and external). Regardless of this, the boxes are closed with a tight lid, providing quick access to the contents and the integrity of the wiring. If necessary, to examine the contents of the housing, an electrician simply removes the cover.

The main materials for the manufacture of junction boxes are plastic and metal. In the second case, sheet tinned steel and alloys containing aluminum are used. An important condition: the metal box must be reliably protected from corrosion.

If the products are located in a strategically important facility where any damage is unacceptable, then it is recommended to buy a box with a screw-on lid and waterproof gaskets. Metal is more reliable in terms of fire protection, since it is able to maintain the integrity of the contents for several minutes. This time is usually sufficient for the operational de-energization of the network.

Plastic elements are also characterized by certain positive qualities. They are resistant to any oxidation processes, are excellent dielectrics. In both cases, the degree of protection against dust and moisture is at least IP65.

According to the geometric shape of the box are round, square and rectangular. The former are used in situations where a small number of cables are switched, the latter - a large number. The specific dimensions of the device depend on the cross section and the number of wires.

Advice! If a junction box needs to be installed in a concrete wall, it is much easier to use round products.

Where and how to install junction boxes

Usually the boxes are located under the ceiling at a distance of 100-200 mm from it. The specific value depends on the height of the room. If the wiring is hidden, then the product is placed inside the wall to a certain depth so that the cover surface is flush with the wall. For open wiring, outdoor boxes are suitable.

In accordance with the rules for the installation of electrical installations (PUE), it is important to provide free access to the cover of the junction box, which is necessary in case of an audit or troubleshooting. If the product is outdoor and is attached directly to the wall, then this condition is met automatically.

When placing the device in a wall recess, two requirements must be met. Firstly, you need to know where it is installed, and secondly, timely access to the product should be ensured without compromising aesthetics. If the latter can be neglected without violating the PUE, then the first requirement is mandatory and important.

You can maintain an aesthetic appearance by gluing beautiful wallpaper, and then carefully trim around the cover of the junction box without removing the part that is glued to it. When choosing alternative finishes, make sure that the color of the surface of the cover and the wall are identical. Try to make sure that if you need to remove the cover, the wall in this place does not collapse. If stretch ceilings are installed, then small hatches should be created to provide access to the boxes.

Wire connection methods

The PUE spelled out five main methods for switching two wires:

twist;
welding;
terminal blocks;
soldering;
crimping.

Twisting

The fastest, simplest, but extremely unreliable switching method. Electrical tape, plastic caps or heat shrink tubing are used to insulate wires.

Twisting with mounting caps

The connection made using special mounting caps will be much better and more stable. Products consist of two parts - an outer plastic, non-combustible, and an inner metal, conical shape with a thread. The latter allows you to literally screw the cap onto the end of the wire, providing a large contact area and excellent electrical parameters. This method allows you to connect two or more wires without using soldering.

To perform the operation, remove the insulation up to 20 mm and twist the wires together. Put the cap on the twist and turn it several times. When choosing a cap, be guided by the number of twisted wires and their cross section. This option saves space by allowing more compact cable placement.

Soldering

A standard method for joining wires using tin and solder. It is characterized by high reliability and durability, but it takes much more time.

wire welding

The first difficulty of the method is that an inverter-type welding machine is needed. This option is considered even more reliable and of high quality, allowing you to turn two cores into one. It should be resorted to only in extreme cases: when grounding a private house with a powerful load, connecting pumps or uninterruptible power supplies for the operation of gas boilers.

Terminal blocks

In accordance with the recommendations in the PUE, when switching two wires from different materials, special screw or spring-type clamps must be used. An easy way that requires a screwdriver. Be careful not to overtighten the clamp bolts.

Crimping

This method involves the use of pressing tongs and sleeves. The latter are selected depending on the cores being connected - aluminum sleeves are taken for aluminum, copper for copper, etc. Please note that with the help of pliers you will not be able to provide a reliable and high-quality connection.

Basic wiring diagrams

After studying and choosing a method for connecting wires in a junction box, read the information on connecting specific conductors.

How to connect sockets

In most cases, sockets are connected in groups, for which a separate current-carrying line is used. Inside the box are three cables with two or three conductors. Brown usually means “phase”, blue - “zero”, yellow-green - “ground”. There are alternatives to these colors with the following standard being red, blue and black respectively.

The wires must be grouped by color, folded, stretched and cut to obtain equal lengths. Be sure to do this with a small margin of up to 10 cm to leave room for repeated distribution and switching. Next, perform switching according to the selected method. If two wires are connected (without grounding), then the circuit remains the same, only simplified.

Connecting a single-gang switch

With switch switching, things are more complicated. There will be three groups of wires with a different connection. One wire supplies voltage from an adjacent box or introductory electrical panel, the other comes from the chandelier, the third from the switch.

The phase wire must be applied to the switch connected to the chandelier. Make sure that the lighting fixture will only receive power when the switch is in the closed position. The neutral and ground wires of the chandelier are connected directly to the shield.

Connecting a two-gang switch

A cable consisting of three cores is laid to a switch with two keys (without a ground wire, which is switched directly with the box). One wire goes to the common contact of the switch, the second - to the first, the third - to the second key. Note the color of the conductor connected to the common pin.

The phase wire must be connected to a common contact, the neutral ones from the input shield and two lighting fixtures are connected directly. Phase wires from fixtures should be connected to the cores on separate switch keys.

Finally, I would like to remind you of the observance of the elementary rules of electrical and fire safety. Never directly connect two conductors made of different metals, such as aluminum and copper. If such switching cannot be avoided, then use boxes with terminals.

Make sure that the phase, neutral and ground wires are connected correctly. If you mix up the "phase" and "ground", then you can cause a short circuit. Following the proverb “measure seven times, cut once”, before hiding a built-in junction box under decor elements, make sure that all consumers connected through it are working.

A junction box is an electrical product within which cable cores are interconnected. Only with the help of it can you correctly connect the socket, switch or lamp to the power source. It also serves to protect connections from

dust, moisture, foreign objects and to prevent accidental contact with them.

Boxes are external (open) and internal (hidden) installation. External are designed to connect cables laid openly: in corrugation, metal hose or plastic cable channels. To enter the corrugations inside, they are equipped with rubber seals to ensure the required tightness.

Seal glands for IP68 junction box

Boxes used in conjunction with cable channels do not have clearly marked places for cables to enter inside. They are sawn during installation on their own, in some models, to facilitate this procedure, the body is made thinner in several places.

Boxes for indoor installation are immured into the walls. Inside, concealed wiring cables are installed. To enter them inside, places with a thinner body wall are provided, usually round. During installation, the body is broken in the right places, cables are inserted into the box, and the free spaces formed in the openings between them and the box body are covered with plaster.

All boxes are supplied with removable covers through which access to connections is provided. Sometimes inside them there are permanently installed terminal blocks for connecting cable cores.

Choosing a place for mounting the box

When installing electrical wiring with your own hands, it is necessary to lay it parallel or perpendicular to the surfaces of the floor and ceiling. The distance from the ceiling to the cables to be laid should be 20-30 cm. It is advisable to place the boxes that feed the switch or socket above them. This is done so that the box can be easily found. In order not to spoil the design of the premises, they are usually bricked up flush with the surface of the walls, and then covered with wallpaper. The box that feeds the outlet and is located above it, if necessary, will be found faster than located randomly.

It is possible to install the boxes above suspended or stretch ceilings, but then it is imperative to provide access to them for possible subsequent repairs. After all, contact connections are the weak point of electrical wiring and over time can weaken or even burn out. For repairs, you will need to open the ceiling. This process will lead to unreasonable material costs, and if the installation location of the box is unknown, to very large ones. The same applies to the location of the box hidden in the wall. It should not be covered with a layer of plaster. To open the lid, the maximum that is allowed to be done is to cut off the wallpaper opposite it. You can then stick them in place or use a patch of residue that inevitably appears after pasting.

To access the boxes located above the false ceiling, ventilation hatches are built into its surface.

The location of the outdoor boxes is determined mainly by the design and savings in cable length. To do this, they are also installed opposite switches, sockets and lamps. But even here you should not install them in hard-to-reach places, so as not to complicate your work.

When installing boxes on the street with your own hands, you need to choose products with a degree of protection of at least IP44.

IP44 junction box

But for guaranteed protection against the penetration of atmospheric precipitation, it is better to install them under visors, roofs, canopies. But the degree of protection of outdoor boxes cannot be reduced, even if rain and snow never fall on them. Moist air, penetrating inside, leads to the formation of condensate, which deteriorates the insulation between the joints or leads to their corrosion. In the first case, a short circuit is possible, in the second - oxidation and broken contacts.

Junction box installation

Mounting the junction boxes in the walls can be done in different ways, depending on the availability of the tool. The best and least labor-intensive option is to use a perforator attachment called a crown.

It is a ring with pobedit or diamond cutting edges, in the center of which there is a concrete drill. The drill performs the functions of centering the crown, and it cuts a round segment out of the wall.

Example of a diamond bit in concrete that can be used to drill holes for junction boxes

After drilling to the required depth, the segment is removed with a hammer and a chisel or a mounting blade mounted on a perforator.

There are bits of different diameters for any size of the junction box

Holes can also be made by the mounting spatula itself, especially for a rectangular or large box. Pre-drill holes along the edges of the required opening with a concrete drill. The section of the wall between the holes is cut down with a spatula and a puncher set in the chipper mode, or with a hammer and a chisel. Instead of a chisel, you can use a wide flat screwdriver with a strong handle. Installation of holes in the walls of a panel house is carried out only with a puncher, other methods will not bring results. At the same time, holes for sockets and switches are installed.

Then strobes are laid, cables are laid in them, the ends of which are wound into boxes so that ends 10-15 cm long stick out of them. It is better to cut the cables in the boxes in advance. The cables must enter the box itself uncut, more than a centimeter long. With a small size of the box, the length of the uncut cable in it must be minimized, otherwise the wires will not fit in it later. If, when sealing the strobe, there is a possibility of cables shifting along the length, then it is better to cut them in junction boxes, as well as in mounting boxes for a socket or switch, after plastering is completed.

Mounting cables in the junction box

After the plaster has hardened, electrical connections can be made. To properly connect sockets and switches in boxes with your own hands, you need to follow the action plan described below.

Separate the split cable cores on the sides, grouping them according to their purpose. First, it is better to decide on protective conductors (PE). In cables, they are yellow-green. Collect in one bundle the PE conductors going to the luminaire bodies, to the sockets, from the power source and to the next box. Be careful: the green/yellow wire going to the switch is not part of this connection. It is important to remember: even if you do not plan to install a socket with a grounding contact, a three-wire cable must go to it, and its PE conductor in the box or shield must be connected. This is done so that in the future it will be possible to replace a conventional outlet.
To prevent the bundle from falling apart, pull it off with a tie or electrical tape. The wiring can be done right away, but it is better to complete the planning process completely, as you will need to untangle the remaining wires.
Collect all zero working conductors in a bundle. They are blue in color, and are assembled from supply and outgoing cables, as well as supplying an outlet. The exception is also cables to switches.
Then we collect together the phase conductors of the incoming and outgoing cable lines, sockets and add to them one conductor from the cables going to the switches. The color of these conductors may be white, black or other, but not yellow-green or blue. From the switch cable we take a conductor of the same color as that of the phase conductors.
We collect the wiring diagram of the lamps. To do this, we take blue or yellow-green wires from the switches and connect them to the remaining unallocated phase conductors of the fixtures. This case is an exception to the rule when yellow-green or blue wires can be used to connect a phase, that is, not for its intended purpose.
We carry out the connection of grouped cores by one of the methods: welding, soldering, installation of terminals.
Isolate connections.
We put the wires in the box.