How to connect in a junction box. Reliable ways to connect electrical wires

Connecting the wires in the junction box requires special care. Not only the reliable operation of electrical appliances, but also the safety of the premises depends on how correctly the work is done.

Wires from the electrical panel are distributed to individual rooms of the apartment or house. Moreover, each room usually has not one, but several connection points (sockets and switches). To standardize the connection of conductors and concentrate them in one place, distribution boxes are used (their other names are “junction boxes” or “branch boxes”). The boxes contain cables from all consuming devices.

The wires in the box are not laid chaotically, but in accordance with clear rules prescribed in the Electrical Installation Rules (PUE). According to the requirements of the PUE, all connections of wires in the box, as well as branches, are made only inside the junction box.

The conductors are directed along the top of the wall, but no closer than 15 centimeters from the ceiling. When the cable reaches the branch section, it descends strictly vertically. At the branch site there is a distribution box. The connections in it are made according to the existing diagram.

The distribution box can be rectangular or round. The number of pins is usually four, but in some cases there are additional pins. Each outlet is equipped with a fitting or thread for securing a corrugated hose. The presence of such a hose or plastic pipe greatly simplifies the process of laying and replacing wires. To replace the wires, it will be enough to disconnect the hose or pipe from the junction box and the consumer, and then pull it out. After replacing the conductors, the hose is returned to its place. If the wires are located in a groove, you will need to break up the layer of plaster, which is much more labor-intensive.

The use of junction boxes leads to the following positive results:

1. The maintainability of the electricity supply system increases. Since all connections are easily accessible, it is much easier to find the damaged area.
2. The overwhelming majority of faults are found at joints. Since all connections are concentrated in one place, it is easier to carry out preventive inspections.
3. Thanks to junction boxes, the degree of fire safety increases.
4. The use of junction boxes allows you to save money and reduce labor costs when laying cables.

Methods for connecting conductors

There are many options for connecting wires in a junction box. The choice of a specific method depends on the following factors:

• the material from which the cores are made (steel, copper, aluminum);
• environmental conditions (outdoor/indoor, working in land or water, etc.);
• number of wires;
• coincidence or mismatch of the cross-section of the cores.

Taking into account these parameters, the most suitable technique is selected.

The following methods are used to connect wires in the junction box:

• terminal blocks;
• Wago spring terminals;
• self-insulating clips (PPE, or plastic caps);
• twisting;
• crimping with sleeves;
• soldering;
• "nuts";
• bolted connections.

Below we will consider the features of each of the listed methods.

Terminal blocks

Terminals are devices made of plastic, the inside of which contains a brass bushing. There are screws on both sides of the bushing.

To connect the wires to each other, you need to insert a conductor on each side of the terminal block and secure them tightly with screws. This joining method is most common in distribution boxes, as well as when installing lighting fixtures, sockets and switches.

Note! The inlet holes of the terminal blocks differ in diameter depending on the cross-section of the conductors intended for them.

Advantages of the method:

• low cost of terminal blocks;
• simplicity and convenience of installation work;
• reliability of conductor fixation;
• the ability to connect poorly compatible materials such as copper and aluminum.

Disadvantages of the method:

1. The pads offered for sale are often of low quality, which is discovered during mating and forces the products to be rejected.
2. Only two wires can be connected.
3. Terminal blocks are not suitable for aluminum or stranded conductor because aluminum is brittle and the stranded conductor strands are too thin.
4. Although the method is reliable, a better connection can be obtained, for example, by soldering.

Wago terminals

Wago spring terminal blocks are one of the most popular devices used in connecting wires.

Unlike standard terminal blocks, in Wago docking is carried out not with screws, but with the help of a special mechanism. The device is equipped with a lever that allows you to secure the conductor while maintaining its integrity. Before using Wago, you need to remove the insulating layer. Next, the cores are directed into the block hole.

Note! There are both disposable and reusable pads on the market. Disposable fasteners mean that they can only be used once, and if the wire is replaced, the pads become unusable. Reusable terminals are more expensive, but can be easily removed and then reused for their intended purpose.

Advantages of Wago spring pads:

1. You can connect both conductors from the same metal and dissimilar materials.
2. It is possible to connect multiple cores (three or more).
3. When fixing multi-core conductors, thin wires do not break.
4. The pads are small in size.
5. Working with pads does not take up extra time, the process is not labor-intensive.
6. The fastening is of high quality.
7. The block has a hole for an indicator screwdriver to monitor the functioning of the electrical network.

Wago has one drawback - the high cost of products.

Self-insulating clips (PPE)

A self-insulating clip (or connecting insulating clip) is a plastic cap, inside of which there is a special spring for fixing the wire.

The advantages of PPE include the following characteristics:

1. Low cost.
2. The products are made from non-flammable plastic, therefore, there is no danger of spontaneous combustion of electrical wiring at the junction point.
3. Easy installation.
4. A wide variety of color shades, which allows you to color-code phase, neutral and ground.

The disadvantages of PPE include:

• low fastening and insulating qualities;
• impossibility of using for connecting aluminum and copper conductors.

Crimping with sleeves

Connecting wires in a junction box using sleeves is considered a method that ensures high quality connections. The essence of the technique is to place the stripped cores in a special tube (sleeve), which is then subjected to crimping by crimping. Next, the sleeve is treated with insulating material, for which heat-shrinkable tubing or regular insulating tape is used. Wires can be inserted from both ends of the tube, or only from one end. In the first case, the joint will be located in the middle part of the sleeve, but in the second case it is necessary that the total cross-section of the cores is no larger than the cross-section of the sleeve.

Advantages of crimping:

1. The connection is of high quality and reliable insulation.
2. Affordable prices for sleeves.

Disadvantages of crimping:

1. The sleeve cannot be replaced once removed - it is a one-time use attachment.
2. The connection will require the use of specialized tools (crimping pliers, pipe cutter).
3. Crimping of aluminum and copper wires is possible only with the help of a specially designed sleeve.
4. The work is labor intensive.

Soldering

Connection using soldering is considered the highest quality of all possible. Before docking, you need to thoroughly clean the conductors. Next, the bare ends are treated with molten solder, after which the wires are immersed in the bath. When the conductors have cooled, insulating material (cambric or electrical tape) is applied to them.

Note! The cooling process should not take place in cold weather, since as a result of too rapid cooling, the material will become covered with microcracks, which will greatly deteriorate the quality of fixation of the conductors.

As already mentioned, the main advantage of soldering is the unsurpassed quality of the connection.

Disadvantages of the technique:

1. A specialized tool is required, as well as skills to handle it.
2. The work requires significant labor costs.
3. The connection is permanent, that is, disposable.
4. There are restrictions on the use of soldering, which are detailed in the PUE.
5. Over time, soldering resistance increases, which is reflected in the form of voltage loss and electrical conductivity.

Thus, despite the reliability of the connection, specialists rarely turn to soldering.

Welding is sometimes used instead of soldering. The essence of this method is the same as in the case of soldering. The only difference is the need for different skills, namely the ability to work with a welding machine.

Twist

Connecting wires in a junction box using the most primitive method - twisting - is not used so often due to significant limitations: poor quality of fastening and the impossibility of joining aluminum and copper conductors. However, twisting is still sometimes found, since it is attractive due to its ease of implementation, as well as the lack of financial costs. Most often, twisting is used when laying temporary electrical wiring. It is recommended to use cambrics as an insulating material.

Note! Twisting is unacceptable in rooms with high humidity, as well as in wooden buildings.

Walnut clamp

The “nut” is a cable clamp with two plates and four bolts in the corners. Before connecting, the insulation is removed from the wires. Next, the conductors are fixed in the plate and covered with a carbolite shell.

Benefits of "nut":

1. Low costs.
2. Installing the “nut” is not very difficult.
3. It is possible to connect dissimilar materials (aluminum and copper).
4. High quality insulation.

Disadvantages of this method:

1. The fasteners weaken over time and need to be tightened regularly.
2. The “nut” is not the best method of mounting in a distribution box due to the excessive dimensions of the connection.

Bolted connection

Bolting is a very simple but effective way of connecting conductors to each other. To complete the job, you only need a bolt, three washers and a nut. The diagram for connecting the wires in the junction box using a bolt is shown in the picture below.

A washer is threaded onto the bolt thread. Next, the core is wound (the insulation must first be removed). After this, the thread is laid with a second washer and another core. At the end, a third washer is placed, which is pressed with a nut. The connection must be covered with insulating material.

The bolted connection has the following advantages:

• low cost;
• ease of implementation;
• the ability to connect products made of copper and aluminum.

Disadvantages of connecting conductors with bolts:

1. Insufficient quality of fixation.
2. You will need a lot of insulating material.
3. The bolt is too large and may not fit into the junction box.

Solving other problems

The connection of stranded wires has a number of features.

Connecting many wires

Options for connecting two contacts were discussed above. If we are talking about connecting multiple contacts, it is recommended to choose among the following options (in order of priority - from the best method to the worst):

• Wago terminal blocks;
• crimping with sleeves;
• rations;
• twists;
• insulating tape.

The rules for docking using the indicated methods, as well as their advantages and disadvantages, are discussed above.

Docking of cores with different sections

To combine cores of unequal cross-sections in a junction box, you will need Wago terminal blocks, although you can get by with standard terminal blocks - the latter option will be cheaper. In this case, it is necessary to secure the cores tightly using a screw or lever.

Note! If the wires not only have different sections, but are also made of different metals, you will need special pads, inside of which there is a special composition to prevent oxidative processes. Similar pads are available in the Wago range.

Cores with different sections can also be secured by soldering.

Joining of stranded and single-core conductors

The combination of conductors with one and multiple cores is carried out in the same way as all others. In this regard, you can choose any of the above methods, but the highest priority is soldering or terminals (preferably Wago).

Procedure for carrying out work in land and water

It is not so rare that there is a need to lay electrical wiring underground or underwater. Let us briefly dwell on the features of performing electrical installation work under these conditions.

Wires can be laid in water, for example, when installing a submersible pump. In this case, soldering of the wire ends is necessary. Next, the connection is treated with insulating material (hot glue), and heat shrink is put on top. If the technology is followed, the joint will be very reliable and safe. However, if you are careless, it will end in a short circuit.

Wiring in the ground is protected in the same way as described above, however, to obtain a secure connection, a more advanced technique can be used. The ends of the cable should be pressed with a terminal block, and the sealed junction box should be filled with silicone. It is recommended to place the underground pipeline in a durable box or pipe to prevent acts of pestilence by rodents. Damaged cable ends are best joined using couplings.

Basic wiring diagrams

Above we talked in some detail about how to connect the wires in the junction box. However, the work is not limited to connecting wires in the junction box. You also need to connect the wires to sockets and switches.

Connecting sockets

A group of sockets is usually separated into an independent line. There are three wires in the box, each of which has a color specific to its purpose. Brown is usually live, blue is neutral, and green/yellow is ground. In some cases other colors are used. For example, phase is red, zero is blue, ground is green.

Before laying, the wires are laid out to their full length and trimmed so that they are the same length. It is necessary to have 10-12 centimeters of reserve - just in case. The connection of conductors is carried out using one of the methods described above.

If only a pair of wires is involved (where grounding is not used), then we are talking about neutral and phase. If the conductors are the same color, you first need to find the phase using a multimeter. For convenience, it is better to mark the phase wire with electrical tape or a marker.

Connecting a one-button switch

In the case of a switch, there are also three groups, but the connection is made a little differently. There are three inputs: from the junction box or electrical panel, from the lighting fixture, from the switch. The phase wire is connected to the switch button. From the output of the switch the wire is directed to the lamp. In this case, the lighting device will only work when the switch contacts are closed.

Connecting a two-button switch

In two-key switches, the circuit is somewhat more complex. A three-wire cable must go to the switch serving two groups of lighting fixtures (if grounding is not used). One conductor is assigned to the common contact of the switch, the remaining two are directed to the output of the buttons. The phase is combined with the common contact of the switch. The neutral wires from the input and two groups of lighting fixtures are connected. Phase wires from lighting fixtures and two conductors from the switch are combined in pairs: one from the switch to the phase of one of the lamps, the second from the switch to the other lamp.

Many people try to entrust the connection of wires in a junction box to professionals, rightly considering this a complex and responsible task. Indeed, electrical problems can lead to short circuits and irreparable consequences. So isn’t this a reason to lay the cable and connect the wires yourself and conscientiously? Moreover, there is nothing particularly difficult in this work. The main thing is to know what the wiring diagram looks like in the junction box.

The basic rule of wiring is to maintain parallels and perpendiculars

If you have the opportunity to lay a new cable yourself or replace an old one, strictly adhere to the basic rules. This will make any subsequent work easier and will protect against the possibility of getting into a live wire. There is a regulatory document (Electrical Installation Rules) that regulates all stages of work. We remind you that each of them must be carried out with the electricity turned off! The wires should always be laid in special grooves in the wall at a height of 15 cm from the level of the intended ceiling, parallel to it.

It is necessary to lower the cable to the outlet or switch strictly vertically, perpendicular to the main wiring. When going around a window or doorway, draw a parallel line at a distance of 10 cm from the slope. It is better to mount the cable in a special corrugated hose or. This will greatly facilitate the subsequent replacement of the damaged area, since the wire itself will not be cemented during the finishing process, you can easily pull it out and insert a new one. As necessary, a distribution box is installed at the junction of all branches; there are several of them in an apartment, depending on the number of connections.

Types and features of distribution boxes

Depending on the conditions (wall thickness, ), two types of boxes can be used:

• internal, for which a hole of the required diameter and depth is drilled in the wall with a milling cutter,
• external ones, which are mounted on top of the wall.

Of course, from a design point of view, the first option is preferable, especially since the lid of such a junction box can be hidden behind finishing materials. The main thing is to first draw up an electrical diagram in the house, so that later, in the event of a problem, you don’t have to look for key components. External boxes, which, of course, will be difficult to hide or disguise, have their advantage: in case of problems, you will not have to spoil the finishing coating of the walls. Distribution boxes are also very diverse in shape, size and material.

The shape and size are usually determined depending on the holes made by the builders, or on the available cutters or crowns that will be used to make these holes. The main thing is that the size matches the number of wires that are supposed to be connected. This directly affects both convenience and quality of work. The material does not play a big role, all options on the market are durable, and the choice is determined primarily by personal preferences and financial capabilities. The only important point is that if you used a corrugated hose, buy boxes that provide for its connection.

Why shouldn't you neglect distribution boxes?

1. 1. They make it easier, help to find the damaged area and replace it.
2. 2. Most often, wire connections become weak points of the system and periodically fail. It is easier to inspect them in a box even at the prevention stage.
3. 3. From a fire safety point of view, boxes significantly increase the resistance of a house to fire.
4. 4. They save time and money, since without them you will have to pull the cable from the electrical panel to each outlet. By the way, you can read how to understand the numerous ones in the article on our website with a link.

Twisting as a basis – is it worth using?

There are several ways to connect wires in a junction box. Twisting remained the most common option for many years. But now it is not recommended to use it due to its unreliability. The rules say that this method does not ensure proper contact, leads to overheating and causes fires. Therefore, whether to use it or not is up to you. Correctly twisting single-core wires is done as follows:

1. 1. Strip both ends of the insulation to a length of about a centimeter.
2. 2. Align the ends parallel to each other. Where the braid begins, they should be held with your fingers; grab the free ends with pliers.
3. 3. Make at least five turns on thin wires so that the ends are securely connected along the entire length. Twist the thicker ones at least three times.
4. 4. The top of the twist is protected with electrical tape.

Stranded wires are connected in a similar way:

1. 1. Strip them to a length of about 4 centimeters.
2. 2. Divide the conductors into half this length.
3. 3. Twist each pair of conductors until they begin to separate.
4. 4. Twist the twisted pairs onto undivided sections and seal with pliers.
5. 5. Insulate.

How to connect wires using mounting caps and terminals

A more modern, efficient and safe twisting option is the use of special mounting caps. Outwardly, they resemble the caps of inexpensive ballpoint pens. The outside is made of non-flammable insulating material, and the inside is metal. This design allows cables to be connected more securely and takes up significantly less space inside the box. The connection is quite simple. The wires are stripped, a little tied together, inserted inside the cap and wrapped until it stops.

Terminal blocks make the process even easier. There are different options available in specialized stores:

• screw - open and closed type;
• for quick installation - with a disposable flat-spring fastening mechanism, with reusable levers and with electrical paste that prevents oxidation and allows you to connect wires from different metals.

They are very easy to use, reliable and durable. Provides a high-quality connection. The idea is simple: a stripped wire is inserted into a special hole and secured with a screw, lever or spring.

Soldering or welding wires in a junction box

Soldering will require some time and skills from you, but will provide a good result. As in previous cases, the wires need to be cleaned, rosin applied to them using a hot soldering iron, then twisted, as in the very first method, and molten tin applied to the twist until the contact becomes monolithic. Additionally, it is better to wrap it with electrical tape.

The welding method requires special equipment, but provides the most reliable contact, since as a result of the work done, essentially a single wire is obtained. The sequential process looks like this:

1. 1. We clean the contacts and twist them in the traditional way. It is important to remove all the braiding; you can go over them with sandpaper.
2. 2. Pour a special welding flux into the recess of the electrode of the welding machine. The device, of course, needs an electric one - an inverter, and a flux suitable for the metal of the wires.
3. 3. Turn on the welding machine, bring the electrode to the welding site and wait until a ball forms - the contact point.
4. 4. Remove the remaining flux, apply varnish and insulate.

Crimping and bolting are two more options

There are two more ways to connect the wires in the junction box. Crimping is the securing of the twist using a sleeve made of the same material as the wire inside. The sleeve should also be of a suitable diameter so that after you insert the wires inside there is a minimum of free space. The sleeve is put on the stripped and twisted ends and fixed with special pliers. Regular pliers are unlikely to achieve a high-quality connection.

The option when the cable is connected using bolts is reliable, but is practically not used due to its complexity and bulk compared to other options. For this, rings are made from the stripped ends of the wire, alternating them with washers, threaded onto a bolt and tightened with a nut. The entire structure is insulated.

Phase, neutral, grounding - how to connect a socket and switches

Before connecting the wires in the box using any of the methods described above, let's look at the materials themselves. They are divided into two types: three-wire wires, where there is a phase, neutral and grounding, and old, two-core wires - only phase and zero. Responsible manufacturers have traditionally used braided wires for these types of wires in common colors:

• phase – brown/red,
• zero – blue/blue,
• grounding – yellow-green/black.

If in your case the colors are different, or all the wires are the same color, find the phase using a multimeter or a special screwdriver and mark the required wires.

This is the simplest connection option inside the junction box. At a minimum, there may be three wires: incoming from the panel, outgoing for further connections, and to the outlet itself. If there are several sockets in a given junction box, then the corresponding number of wires will be added. As a result, it is necessary to connect all phases, all neutral and grounding conductors. Leave a small supply of wires in case of repairs. If you have to connect a single-key switch, do not worry. Everything here is also quite simple:

1. 1. The phase from the cable coming from the electrical panel goes to the switch, and the zero goes to the lamp.
2. 2. The zero from the switch is connected to the phase of the lamp, then it will light only when the switch is on.
3. 3. All three grounds are connected to each other.

Now let's figure out how to wire a two-key switch. This option is more complicated than the previous ones, but not much. The sequence of connections is as follows:

1. 1. The phase from the incoming cable is connected to the switch.
2. 2. Zero from the incoming wire to the lamp.
3. 3. The two remaining wires from the switch cable are connected each to their own button and connected to the lamp.

It happens that wires from both sockets and switches are collected in one distribution box. In this case, you need to show a little more patience and care in order to consistently and reliably make the wiring in the box. If you have not been involved in the process of installing wiring inside the walls, it will be difficult at the initial stage to determine which wire leads to what. This will most likely have to be found out experimentally, one by one connecting and checking the functionality of sockets and switches. Most importantly, do not forget about safety precautions!

Upon completion of work, mount the box into the hole, if you have not already done so, close the lid and use electricity with pleasure and a sense of accomplishment.

When repairing electrical wiring yourself, you should pay special attention to the connection of wires in junction boxes, because electrical engineering, as electricians say, is the science of contacts, both desirable ones, ensuring an uninterrupted supply of electricity, and unacceptable ones, due to which many accidents occur.

This article, with the help of links to other materials of this resource, will present all the minimum knowledge and skills required by a home handyman for successful electrical installation, and will also describe step by step the entire process of connecting wires in a junction box, starting from the preparatory stages, ending with the introduction of an installed home network into operation.

The scheme is the most important stage

For an experienced electrician, it will not be difficult to connect a switch and a light bulb without a drawing, making a connection of wires in a junction box, guided by the color marking of the cable cores or by the results of testing already installed wiring.

But experienced craftsmen succeed in such work only because connection diagram clearly imprinted in the mind thanks to many years of practice.

A simple diagram of wire connections in a junction box when connecting a switch and a light bulb

If a master needs to carry out electrical wiring at any facility, then he will begin first by designing a circuit, if other specialists have not done this before him. Of course, there are standards, GOST and SNiP, according to which all electrical wiring drawings are made, but for an apartment or private house, a hand-drawn diagram is suitable, the main thing is that it subsequently works properly and safely.

This approach not only protects against errors, but also allows you to save time by dividing labor - when carrying out electrical installation in a junction box, the electrician will not be distracted by drawing up a wiring plan, while simultaneously trying to keep the planned lines and connections in his head.

A more complex connection diagram for a two-key switch

Examples of schemes for and apartments can be viewed by following the links. You will also need to familiarize yourself with the graphic symbols of the network elements so that you can consult with a familiar mechanic by showing him the diagram, or in the future carry out electrical wiring repairs by checking the saved drawing.

The importance of planning electrical wiring is also determined by rationality and efficiency. When drawing up a wiring diagram, you need to draw up a plan in such a way that there are as few junction boxes in the apartment as possible, because each connection of wires increases the risk of losing contact.

Example of a hand-drawn wiring diagram (blue circles indicate junction boxes)

When connecting one socket or switch, many electricians advise doing without a distribution box altogether and connecting the wires in the socket box. This decision is determined by the reluctance of apartment owners to provide access to the distribution box, as required by the PUE (in their opinion, the interior of the home is deteriorating). The socket or switch can be easily disassembled, which provides access to the connection of wires in the socket box.

Quote from PUE

A detailed story about the various wiring diagrams in junction boxes is shown in the video:

Correct pin markings

In order to connect the wires in the junction box according to the diagram without undue doubt, it is necessary that the terminals of the laid electrical wiring be marked. Very often, disconnection (dividing the main electrical wiring line into several branches) is made when all the wires have already been laid and hidden under the plaster, and there will be no way to visually trace the purpose of the cables.

It's easy to get confused without being sure of the purpose of the same cables

In order not to waste time on cables, which is also described on this site, you need to mark their ends at the stage of laying the cables. In some cases, if there are few wires in the distribution box, you can be guided by the color of the insulation of the current-carrying conductors. But with a large accumulation of cables, the colors of the wire insulation will be repeated, so the likelihood of error increases.

To eliminate the possibility of incorrect connection, you must label ending laid cables in any available way. The industry produces many different tags designed to mark terminals. Very often, electricians use transparent heat-shrinkable tubing by inserting a strip of paper with a terminal symbol inside.

Samples of industrially produced cable marking tags

You can also use transparent tape to wrap it around tags with inscriptions. As a last resort, use a marker or felt-tip pen to write the designations directly on the wire insulation or on the wall - but there is a risk that the inscriptions will be erased during the installation process.

Electrical wiring terminals are marked on the wall

You should also strictly adhere to the color marking of the cables (brown, red, black - phase, blue - working zero, green with yellow stripes - protective conductor PE).

Generally accepted color coding for cable core insulation

Installation of distribution box

Before starting electrical installation, you need to make sure that the junction box is securely fixed. , which depend on the type of wiring, are also described on this site. The importance of fixation is determined by the possibility of damage to already connected wires when manipulating the junction box and cables.

When working with single-core wires, frequent bending of the current-carrying wires should be avoided. Although stranded wires allow frequent bending, mechanical loads and the weight of a loose cable of hanging electrical wiring can damage the finished connection, so it is important not to violate electrical installation technology.

PUE requirement for fixing cables and boxes

If hidden wiring is installed in a brick or concrete wall, then the wires are laid in a groove made manually or using tools (grooving), and socket boxes and distribution boxes are mounted in holes that are drilled into the wall using a special crown. Fixation is carried out using plaster or alabaster.

Box bit for drilling holes for distribution boxes

Each type of wire connection requires a certain length of leads. For example, when using very bulky connecting blocks that have bolted connection terminals, craftsmen try to leave as little free length of wires as possible so that all connections fit into the box.

But, if welding of wires is used, then the length of the bare conductors should be about seven centimeters to prevent the insulation from melting during strong heating, plus the length of the insulated conductors for convenient and safe installation. Long exposed connected wires are insulated and laid in a junction box.

Wire connections are made by welding

The above examples mean that, regardless of the chosen method of connecting the wires, the length of the leads protruding from the junction box must be at least ten centimeters, because excess conductors can always be cut off, but it will be extremely difficult to extend them, and the reliability of the entire electrical wiring line will deteriorate. .

Conductor training

At this stage, the master must finally decide how to connect the wires in the junction box, and accordingly prepare guides– remove the insulation and bend the cable cores. A list of existing types of wire connections is given below, and now, regardless of the chosen method, special attention should be paid to the quality of stripping and preparation of conductors for electrical installation.

Stripped wires are ready for connection in the junction box

To carry out any electrical installation, the master must have, which you can familiarize yourself with by clicking on the link. At this stage, the wires are prepared for connection - stripping of insulation. Particular care should be taken in this process, since when using improvised means (knife, pliers, wire cutters), invisible damage to the current-carrying wires is possible.

Professional electrician's tool kit

As wires are bent and subsequently installed, subtle cracks in the metal can become larger, impairing electrical conductivity and possibly leading to breakage and loss of contact. At high currents, a large amount of heat will be released in the thinnest section of the circuit (at the crack site), which can heat the insulation and even the metal of the conductor itself to the melting point.

With a large current in a broken conductor, an avalanche-like process occurs - when heated, the resistance of the material increases, which further increases the heat release. This process ends with the melting of the conductor metal and the appearance of an electric arc, which, burning other wire connections in the junction box, renders them completely unusable.

Photo of an electric arc burning in a junction box

Without a doubt, a real master, even with the help of a kitchen knife, will be able to carefully and quickly remove the insulation without damaging the current-carrying conductor. But for people without experience it will be very difficult to avoid subtle damage to the material of the conductors, therefore, in order for the connection of wires in the junction box to be of high quality, it is necessary to use special ones (strippers).

Variety of stripping tools

Many people have seen the picture that some craftsmen remove insulation with the help of teeth. There is absolutely no need to follow this example, in which case purchasing a professional insulation stripping tool will cost less than the services of a dentist.

An overview of various stripping tools is shown in the video:

Wire connection methods

As already mentioned, for various methods of connecting wires to a junction box, there is its own electrical installation technology, which consists of the length of stripped conductors, their bending and the use of appropriate tools.

Since each of the possible methods has many specific nuances and requires the use of special tools and skills, the types of wire connections are presented below in the form of a list with links:

• Terminal blocks;
• PPE caps;
• Connecting sleeves;
• Welding of conductors.

Wiring in a junction box using terminal blocks

Each of the above methods has its own advantages and disadvantages, which you must familiarize yourself with by studying the materials and following the links provided. You should choose the type of connections for doing electrical installation yourself based on the availability of tools, skills, the ability to purchase materials and the expected quality of contacts.

Most reliable welding of wires is considered, but it requires a special welding machine and specific skills. Soldering conductors, which also has good performance, requires soldering iron skills. Wago terminal blocks are quite easy to install, reliable if the products are correctly selected according to the load, and allow the connection of multi-core wires without the use of special lugs, but you should be wary of counterfeits.

Connections in the junction box are made using Wago terminal blocks

The use of sleeves is reliable; when using special products, it is possible to connect copper and aluminum, but the connection itself requires special pliers and is non-separable, which does not give a chance for easy correction of electrical installation errors. PPE caps are reliable if the technology is followed and the diameter is selected correctly. Terminal blocks require bolted connections to be securely tightened.

PPE caps in distribution box

It should be remembered that according to the PUE, twisting of wires is not allowed in its pure form

Twisting in its pure form is not included in the list of compounds allowed by the PUE

Testing wire connections in junction boxes

After all connections have been made, the exposed areas of the conductors are insulated using heat-shrinkable tubing, and the wires are laid in junction boxes. The boxes themselves are left open until the installed electrical wiring is tested. First, voltage is supplied to the connected lines by turning on the corresponding circuit breakers.

Insulating connections in the junction box using heat shrink tubing

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

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

Melted insulation of one of the connections in the junction box

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

The connection of wires affects the safety and reliability of electrical wiring. It is performed in different ways, using connecting devices and devices, depending on the characteristics of the wires.

Why use a junction box?

A distribution (otherwise a junction box, a branching box) is a type of installation box in which wire switching and electrical connections are made. It can be round, rectangular, square in shape, plastic, steel, fiberglass, aluminum in material.

The device is a container, the purpose of which, with any method of connecting wires in a distribution box, is to hide the branch of the electrical network. In addition, it allows you to effectively redistribute the load on networks and prevent short circuits in them.

There are many ways to connect wires in a junction box. The simplest one - twisting - was previously a priority. Today it is considered dangerous and unreliable. It was replaced by special connecting devices, devices designed for the various characteristics of the cables being connected.

Methods for connecting conductors

Correctly connecting the wires to each other means ensuring the reliability and safety of the electrical network. There are numerous types of wire connections. You can use long-used ones - twisting, soldering, bolting. It’s easier and faster to get the job done by using a cable connector - a special device that allows you to reliably connect cables of different diameters, single- and multi-core, from various materials,

Using Terminal Blocks

Blocks for connecting wires are a type of electrical installation products. They are called terminal blocks, terminals, terminal blocks, terminal blocks, KB, terminal clamps, terminal connectors. Contains 2 metal contacts or more. The latter have nodes in which cables are secured and are placed inside a dielectric housing, often sealed (filled with gel).

There are many types of terminal connectors. They are distinguished:

• by installation method: screw, detachable, push, barrier, pass-through;
• single-, double- and multi-row;
• for one-, two-, three-row and multi-tier cables;
• angular and straight;
• for single- and multi-core, flexible conductors;
• according to the method of wire clamping: screw, spring, knife, end.

The cable connector is inexpensive. Contains a clamping cage enclosed in a plastic housing. Phosphor bronze and stainless steel are used to make the clamp; housings – polyamide; screws - brass, nickel-plated or galvanized steel.

Connect the electrical wires to the device in the following order:

• the insulation is removed from the ends of the cables;
• 1 conductor is inserted into the clamping cage, fixed, depending on the type of terminal block, with a screw, spring, or knife;
• To form a network, 1 or more conductors are installed in it and clamped in the same way.

Spring terminals

These are terminal blocks in which the cables are fixed by a plate (busbar) under the action of a spring force. Types of connecting electrical wires using the following devices:

• fast, allowing you to save up to 80% of the electrician-installer’s time;
• do not require the use of a screwdriver - the conductor is fixed by the terminal mechanism after insertion;
• provide a constant contact force on the conductor and do not deform it;
• allow you to connect cables of different materials and cross-sections.

How to connect two wires:

• remove the insulation from the conductors (1 cm);
• raise the lever on the clip body;
• insert the end of the cable into the connector;
• lower the lever into place.

Terminal blocks without levers are available. In them, the wire is automatically clamped after being inserted into the groove of the connector. Most of them are produced filled with a special gel inside, which makes the devices sealed connectors, providing the highest level of protection.

Installation of PPE caps

This type of cable connector has a conical cap made of non-flammable plastic. Inside it may contain a conical metal spring or a bushing with a large thread. Used for better twisted connections, it protects it by providing reliable insulation.

Caps with a spring are screwed onto a pre-made twist. The spring moves apart due to the pressure of the conductors, providing additional compression at the connection point.

Threaded caps can be screwed onto cable ends without pre-twisting. After making 2-3 turns, a reliable twist connection is obtained inside the PPE cap.

Crimping with special sleeves

The electrical wire connector consists of tubular elements - sleeves. Suitable for networks with medium and high current. Provides good electrical contact, the connection strength is the highest among the methods used. The disadvantages of this method are that the conductor cannot be disconnected in the future.

The wires are connected without soldering in the following order:

1. Remove the insulation from the cable ends. A knife or a special tool is used.
2. The ends are inserted inside a tube made of a similar material. The placement must be tight - additional compaction, if necessary, is done by inserting pieces of bare cable into the tube.
3. The sleeve is compressed using special press pliers. They do this near both ends, and in different directions. If the cross-section of the sleeves is more than 120 mm², the cable connector is crimped with a tool that has a hydraulic drive.

The connection of wires obtained using special crimp sleeves must be insulated.

Soldering or welding

Reliable connection of wires in the electrical network is ensured by welding. As a result, a solid conductor is formed that does not oxidize, has minimal resistance, and eliminates short circuits.

How to properly connect wires by welding:

• remove the insulation from the conductors, clean the conductors with sandpaper until shiny;
• connect the wires by twisting;
• Flux is poured into the recess of the carbon electrode;
• turn on the welding machine (24 V, minimum power - 1 kW), press the electrode to the welding site, hold until a contact point in the form of a ball is formed;
• clean the flux from the welding site and cover the contact point with varnish;
• isolate the connection.

Soldering electrical connections gives the same results. Its implementation is similar to welding. Difference:

• in the use of solder, which is melted by a soldering iron;
• mandatory filling of twisted solder inside.

Soldering connects the cables securely, but the method is not effective:

• if cables are exposed to heat;
• when connections are subject to mechanical stress.

Stranding and insulation

The twisting method is the simplest of conductor connections. Used when connecting aluminum wires to each other or others, but from the same material. It is considered unreliable, therefore it is prohibited when installing electrical networks. When deciding what is better for forming a network, Wago terminals or twisting, they give preference to the first option.

How to twist wires correctly:

• remove the insulation at the ends of the conductors using a knife;
• grab the ends with pliers and, holding the cables with the other hand, make 3-5 twisting movements;
• the twists are covered with insulation.

Walnut clamp

Wire clamps with this name have a cube-shaped insulated body made of polycarbonate. It contains a metal core, which includes 2 dies with grooves for the wire and an intermediate plate. The latter are compressed together by 4 bolts.

Walnut wire clamps ensure a secure connection of cables. They are produced in different sizes of the latter - markings are applied to the surface of the dies.

Using a bolt

The bolted connection of the wires is reliable, but has large dimensions, which makes it impossible to place a large number of them in modern junction boxes. This is done using a bolt, washer and nut. The order is as follows:

• remove the insulation from the ends of the connected cables and form rings in these areas;
• a metal washer is placed on the body of the bolt;
• place a ring of one of the conductors on it;
• closed with a steel washer;
• put a ring on the next cable;
• install 1 more washer;
• seal everything with a nut and cover it with insulation.

Connecting several wires

This can be done by twisting, but provided that all cables are made of the same metal. Then it is better to close their combination with a PPE cap and solder it, which will increase its reliability and safety.

For such situations, a cable connector in the form of a terminal block is suitable, designed for single-, double- and multi-row connections. You can connect several conductors with 1 bolt.

Connection of cores of different sections

The best for this option are terminal blocks designed to connect cables of different cross-sectional sizes. Twisting with soldering or a bolt will do.

Combining stranded and single-core products

You can combine multi- and single-core cables by soldering or bolting. But, when choosing which is better - twisting or terminal block, you need to give preference to the latter. There are types of terminal blocks that are designed for such situations, regardless of the cable material.

The junction box is of great importance in the electrical circuit.

It distributes wires for further electricity consumption.

If you decide to do your own wiring, then first understand all the intricacies.

To understand this process well, let's look at it step by step. We’ll also talk about the types of wire connections and the features of connecting the box.

Types of wire connections

Several types of wire connections are used. Choose the option that is more suitable for your case.

Twist

Now this method of connection is prohibited due to safety regulations due to unreliability.

If you decide to choose this connection option, you should understand the possible consequences.

Twisting is very simple: peel 1 cm of insulation from the wires, and then carefully twist them onto each other. The number of turns depends on the diameter (the thicker, the fewer turns).

Crimping

This method is used very often. It is produced using a special sleeve that matches the diameter of the bundle of wires.

The sleeve material must match the cable material.

The process is carried out using press jaws in the following sequence:

1. Remove the insulating layer from the wires along a length equal to the sleeve.
2. Twist them into a bunch and insert them into the sleeve
3. Press the sleeve with the wires using press pliers.
4. Insulate the connection with available insulating material.

Welding

After welding, you get a whole wire that will not oxidize, unlike other connection methods.

The following equipment is required for welding:

• 24 V welding machine with a power of 1 kW,
• flux,
• electrodes,
• protective equipment (mask, gloves).

This is done as follows:

1. Remove the insulation and sand them until shiny with sandpaper.
2. Connect the wires using a twist.
3. Pour flux into the recess of the electrode.
4. Turn on the welding machine, press the electrode against them and hold until a lump forms - a “contact point”.
5. Clean the contact point from flux and coat it with varnish, and then insulate it.

Spike

It is performed in the same way as welding. Only the connection is made using solder heated by a soldering iron.

It is important that the solder penetrates inside the twist. This method should not be used in places where the cable is very hot and in places where there are mechanical loads.

This method is simple, fast and inexpensive. In this way, you can connect both identical wires and those of different composition.

The connection is simple: first, about 0.5 cm of insulation is removed, and then they are inserted into the clamp and tightened with a screw.

Bolted connection

This connection is quite reliable, but very bulky.

Therefore, it is used mainly in old-style boxes, since it simply does not fit in modern compact boxes.

The operating procedure is as follows:

1) Place a steel washer on the bolt.

2) Place one of the wires, stripped of insulation and twisted into a ring, onto the bolt. Do the same with the second one.

3) Put on the next washer.

4) Place the ring on the second wire.

5) Put on the last washer and tighten everything with a nut. Insulate the entire connection (although insulation will only add bulk to it).

Connection with self-clamps

The most modern type of connections, easy to use.

Among other things, inside the clamps there is a paste that prevents metal oxidation, which means that different conductors can be connected without problems.

The connection is made in the following sequence:

1. Remove about 1 cm of insulation from the wires.
2. Lift up the clamp lever.
3. Insert the wires into the connector.
4. Pull the lever down (if there are no levers, just snap the clamp)

For safety, reliability and correct connections, it is necessary to know the specific designations of wires.

Wires marked “zero” (blue) and ground (yellow) are connected according to color (see diagram). If you are installing a two-wire system, the circuit is the same except for the ground wires.

The process of phase desoldering (black or red) is much more complicated. If you plan to run only the wire through the box to connect the outlet, then connect their phases together.

If material is used from the box for single-button switches, then it must be twisted together with all the phase wires for the switch. Connect the same one coming from the switch with the phase wire going to the lighting fixture.

The result should be four connections.

When using two-key switches in a three-wire system, a four-wire wire must be used for the chandelier.

In the case of two-wire wiring, a three-core cable is used, since grounding is excluded from the circuit.

Not counting the separate grounding twist, there should be four connections in the box. Wires marked “zero” (blue) are connected to each other. The phases of the sockets are connected to the power cable and connected to the common terminal of the switch with two keys.

Two wires should go from the switch to the lighting fixture.

From all of the above it follows that desoldering the box is a very simple process. It is enough to understand the designation and order of their connection.

Sequence of actions when installing and connecting the junction box

First, prepare everything you need for electrical installation work:

• cables 3*2.5, VVG,
• cables 2*2.5, AVVG,
• two-gang switch,
• fastenings,
• lighting fixture,
• socket,
• round pliers,
• roulette,
• wire cutters,
• pliers,
• flat screwdriver,
• hammer.

2) Applying markings. Mark the installation locations of electrical appliances and where the wires will pass.

3) Installation. First, turn off the power supply.

Route the wires to the junction box (it is better to lay the cable in pre-prepared grooves). Secure the wires using small nails or plastic staples.

In wooden houses, special mounting boxes are usually used.

4) Connecting electrical appliances and connecting wires.

Run about 10 cm of cable into the pre-installed junction box. Remove the overall sheath from the wires and about half a centimeter of insulation from each core.

Connect them using terminal blocks. In this case, a two-wire wire is used (one wire is zero, the second is phase).

Connect the socket and lighting fixture to the neutral cable. Connect the wire with the phase to the socket and one core of the switch cable. Take the second wire of the switch cable and connect it to the first button, and the third to the second.

5) Check the system operation. Turn on the power and check the operation of the outlet and switch.

Everything should work properly. The process is complete.

Now you know how to connect the wires in a junction box and how to connect electrical appliances. Using this knowledge, you will easily cope with the installation of electrical appliances.

Video: 3 best ways to connect