Terminal blocks for connecting wires: types, connection principles, pros and cons

When to connect cables

Cable connections will be required in case of poor-quality wiring performed earlier, or due to errors made during installation work. To restore power to the house, you need to connect the electrical wires. You can make a connection in ways that are divided into 2 groups:

1. For the first group, no special equipment is required.
2. The second group already requires certain skills and professional tools.

Work on connecting cables must be carried out in compliance with safety regulations.

Types of cables for connection

The most common cable for home electrical wiring is a PVA connecting cable, consisting of two insulating layers.
Copper strands, stranded, twisted along the central axis. The wire is flexible, making it great for a variety of connections. The voltage of connected devices must be up to 380 Volts. The cross section is selected depending on the load:

• for a current of 6 A, PVA with a cross section of 0.75 mm is used;
• for 10 Amperes - the cross-section is 1 mm;
• for currents of 16 A – 1.5 mm.

In addition to the PVS wire, for connection there are multi-core cables ShVVP, PUGNP, PRS, KG. They are used less frequently for home wiring than PVS.

Possible connection methods

Connection methods may vary depending on the following factors:

• types of connected cables;
• characteristics of the electric current of the line;
• design features of the equipment in which the wire is used;
• operating conditions of the connection and other points.

Let's consider possible connection methods to ensure the necessary contact.

Twist

One of the simplest ways. In previous years, it was widely used for electrical wiring in apartments and residential buildings. But now, according to PUE standards, it is necessary to use soldering, welding or pressing.

The connection is made in this order:

• The insulating coating is removed and about 5 mm of wire is carefully stripped from each end. If the core cross-section is more than 2.5 sq. mm, the length of the cleaned area is increased accordingly,
• the stripped conductors are placed parallel, aligning the ends, and twisted tightly, grasping with pliers,
• the resulting twist is soldered or welded.

Methods of twisting wires
An alternative method, when it is important to maintain the length of the wire, involves the opposite arrangement of the wires, crossing them and twisting them by hand. Next, the density is increased using pliers.

Twisting must be performed when connecting conductors of the same metal. Otherwise, the contact will be uneven and will oxidize over time.

Soldering

It is highly reliable. It is possible to solder parallel or twisted wires. But in the first case, it is difficult to ensure high reliability due to the softness of the solder and the difficulty of fixing the wires.

Performed in the following sequence:

• the ends of the wires are pre-cleaned, etched, and tinning;
• The wires are twisted and soldered using rosin.

Also read: What you need to know to assemble a welding machine with your own hands

Sequence of actions when soldering
When the soldering has cooled, the contact is insulated with electrical tape or heat shrink.

Brewing

Allows you to significantly increase the reliability of conventional twisting. Performed using a graphite electrode or a gas torch. Considering the complexity of performing work using gas and oxygen cylinders, let’s consider an example of obtaining a connection by electric welding:

• strands up to 100 mm long are twisted, with the overall contact dimensions being half that size,
• ends are trimmed,
• a negative contact is connected next to the insulation with a powerful clamp,
• current mode is set,
• the ends are welded. The duration of the operation is no more than 2 seconds. If necessary, welding is repeated until a smooth ball is obtained at the end of the joint.

It is recommended to use an inverter device that provides the ability to regulate the current. As a last resort, you can use a unit with power characteristics of at least 0.6 kW and voltage up to 24 V.

Crimping

Allows you to achieve greater connection density than with conventional twisting. Therefore, this method can be used even when copper comes into contact with aluminum. Provides for clamping the cores in a thin copper or aluminum sleeve.

Execution order:

• the ends are stripped to a length of up to 100 mm exceeding the size of the sleeve;
• the ends are placed inside the sleeve in one-sided or opposite order;
• the sleeve is pressed up to 2 - 3 times with an indentation from the edge of up to 10 mm. It is important to maintain the integrity of the wire without crushing it.

In addition to reliability, this method is good because it allows you to connect conductors of different diameters.

Bolted connection

Performed using a bolt, nut and washer. The bolt is selected with a thread size that depends on the diameter of the core, allowing it to be freely bent into a ring.

The wires are connected in this order:

• the joints are trimmed to the length necessary to make a ring along the diameter of the bolt;
• the cleaned areas are bent into a ring;
• the conductors are put on the bolt, a washer is placed on top and clamped with a nut.

Also read: Is it possible to connect copper and aluminum wires?

Bolted connection

The length of the selected bolt depends on the number of conductors to be connected. The washer is made of conductive material.

Using a terminal block

A terminal block is a special clamp in which the ends of the cores are clamped using a round or rectangular washer. If a pressure washer is used, the work is performed in the following sequence:

• the stripped ends of the wires are inserted under the washer;
• the contact is clamped with a bolt.

You can place two conductors on one side.
Clamps with a round washer are identical to bolted connections and are made in the same order.

Such connections are highly reliable, but they are quite cumbersome.

Application of WAGO self-clamping terminal blocks

These terminal blocks are made in the form of a package of clamps that allow you to connect from 2 to 8 wires.

This company is one of the most famous in this area. The connections obtained using proprietary terminal blocks ensure compliance with the requirements of the PUE, achieved due to the tightness of the contact and the presence of a spring clamp that prevents spontaneous loosening of the wires.

The connection procedure is no different from that described above.

Using tips

To obtain tight contact, tips are used - pieces of tube made of conductive material, flattened on one side.

The wires are inserted inside, the tip is compressed by a crimper in the manner discussed in the section on crimping.

Soldering tips

Connections using lugs can be made not only by crimping, but also by soldering. To perform the work you will need preparation:

• copper cable with stripped ends;
• a tip designed for this type of connection;
• a bath filled with molten tin;
• container with orthophosphoric acid;
• soda solution.

Algorithm of actions:

• the cleaned ends of the cables are inserted into the lug;
• the contact is immersed in acid, then in tin until the solder flows inside;
• at the final stage, the contact is immersed in a soda solution to completely neutralize the acid.

The connection is ready for use after complete cooling and rinsing under running cold water.

Using special connectors

Another method involves the use of special connectors - sections of pipe, inside of which threads are cut and bolts are screwed in. Such a contact can be made permanent by cutting off the screwed-in bolt after clamping the wires.

Also read: How to connect a motion sensor to a light bulb

The connection procedure is similar to the bolt contact.

Via couplings

Couplings can be used when the operating conditions of the connection include high humidity or exposure to atmospheric factors. The coupling body can be made of plastic or metal.

The coupling is selected based on the operating conditions of the contact. The wires are connected, similar to the method with terminals, with the contact located inside a sealed housing.

The quality of electrical installation work largely depends on the reliability of the connection. Therefore, it is very important to correctly determine the method of contact and securely fasten the wires to ensure uninterrupted transmission of current through the connection point.

Basic requirements for terminal blocks for connecting wires

Various types of terminals
Electrical installation products are manufactured according to special standards and regulations. There are several requirements for terminal connectors:

• Resistant to high temperature and combustion. Materials used for the housing are self-extinguishing upon fire. Polyamide is recommended and is used by WAGO and Legrand.
• Reliable and fast fixation of contacts. It is recommended to leave sufficient cable length for communication to avoid tension.
• The properties of the clamps should not change during the period of operation.
• The size of the contact plates should prevent contact between cores of different materials. To ensure low resistance, copper and brass parts are coated with a special paste.
• Information about the main characteristics of the device is printed on the product body.

One of the essential requirements is protection against accidental access.

Terminals

Most often, cable connectors today take the form of terminals. They are made of brass. In this case, the connected ends of the cable do not contact each other directly. Therefore, using such structures, it is possible to switch identical conductors, cores of different cross-sectional sizes, made of different materials.

To be able to create the correct joint, you need to select the appropriate types of terminals. They differ in the nominal current rating, as well as the permissible diameter for the wire. All characteristics of the terminals are indicated on their housing.

Some commercially available terminals may contain a special filler. The gel prevents oxidation processes, increasing the reliability of the connection. Terminals can be knife, spring, or screw.

Advantages and disadvantages of terminal switching

Using terminals, you can connect copper and aluminum wires.
To connect a power cable on the street or in the house, the simplest option is to use connecting terminals for leads. Main advantages of the method:

• constructive variety of connectors;
• possibility of dismantling and repair;
• simplicity, speed and accessibility of installation;
• electrical safety, dielectric housing protects against electric shock;
• resistance to mechanical load and vibration;
• possibility of switching metal conductors of different sections and materials.

Flaws:

• allocation of additional space in panels and distribution boxes;
• high cost for large-scale work.

Electrical clamps are durable and reliable; to install them, you only need a screwdriver.

How to choose the right terminals for wires

Before purchasing wire connection terminals, you need to research the power cable. You will need the following information:

• section;
• number of cores;
• conductor material.

An important criterion is the rated current. This characteristic is indicated by the manufacturer. If it is insufficient, the connector will begin to heat up and melt. The material of the case matters. For household appliances, sockets and switches, products made of polypropylene and polyamide are suitable. It is recommended to install ceramic devices in power buses. The last criterion is terminal size. It should be compact to fit in limited space.

Types of electrical connection blocks

Devices for switching wiring are selected depending on the purpose. Among the many models, the best option is selected. There are several ways to fix conductors in blocks.

Spring

Spring terminal design
A common version of spring-type products is self-clamping terminals. They are disposable and reusable. In the first case, after fastening, the wire cannot be pulled out without significant damage. In reusable models, it is released using a lever. Advantages of the method:

• installation does not require experience or tools;
• the stripped end of the wire is fixed with a spring after insertion into the groove;
• The connection is reliable and durable.

Spring-loaded copper contact plates secure stranded wires without damage. The quality of the wiring connection does not depend on the professionalism of the technician. Even a beginner can easily handle the self-clamping mechanism. The leader in the production of devices with automatic contact clamping is the German company WAGO. The disadvantage is the high cost of the products.

Screw

Screw
Terminal Screw terminals hold the wire to the terminal pad using screw pressure. The metal clamp is housed in a plastic housing. Advantages of switches:

• possibility of reuse;
• the block consists of many parts;
• installation is carried out with one screwdriver.

Disadvantages of screw pads:

• sensitivity to vibration;
• not recommended for aluminum cable;
• Regular maintenance (tightening of screws) is required.

Screw type terminal blocks are not suitable for multi-core wires. It is recommended for single-core copper cable. When tightening the screws, a certain amount of force is required; experience is required to perform the connections correctly. Well-known manufacturers of screw switches are Legrand and Wiedmuller.

Knife type

Knife-type
terminal Knife-type switches are installed in the circuits of the grounding system. They are recommended in areas where the wire is not cut for safety reasons. Their feature is that there is no need to remove insulation from the contact. The wire is inserted into the terminal block, where a special knife cuts through the braid and securely fixes the core. This type of connector has its advantages:

• installation is accelerated;
• compact dimensions;
• No professional skills required for installation.

Knife terminal blocks are not used for power circuits; most often they are used to connect audio equipment.

Terminals on plastic blocks

The terminals are used to connect two wires. They come with different hole diameters for the conductive core. The devices allow you to connect cables with one or more cores, conductors of various cross-sections. The design of the pads eliminates oxidation processes when connecting wires made of copper and aluminum. Some models are filled with a paste that prevents corrosion. A special recess in the plastic prevents pressure on the core when tightening the screw. The transparent body of the products makes it possible to assess the condition of the contacts.

Walnut Branch Clamps

Nut for connecting wires
The main branch branch clamp without separation consists of a plastic body and metal plates with bolts. The dies have grooves for contacts. When choosing a model, take into account the cross-section of the main wire and branches. This connector can be used to connect aluminum and copper wires. Between the two dies there is a brass separating plate.

For distribution boxes

The wires of all connected devices are brought into the distribution box. Terminal blocks for junction boxes are designed for branching electrical wiring. Their body is made of polycarbonate, and the contact pad is made of copper. Fixation is carried out by a spring mechanism.

With fuse

The devices have an additional element in their design - a fuse. The terminals are oversized. They are installed in DC and AC networks. Scope of application – switching electrical appliances without built-in fuses and installation in a panel on a DIN rail.

How to connect a terminal block to a DIN rail

Installing terminal blocks on a DIN rail does not take much time, even for novice electricians. Many companies provide their customers with devices with an automatic latch or “tab”; to familiarize yourself, just look through the company’s catalog where the technical characteristics of the panels suited you.

Photo - How to connect a terminal block to a DIN rail

First you need to calculate the number of terminal blocks. The designation of the terminals M6/8 indicates that this is a device with a screw pitch of 6 and a width of 8 mm; accordingly, by carrying out simple mathematical calculations, you can calculate the required length of the DIN rail and the dimensions of the cabinet. All terminal blocks are very simply connected to each other; to do this, you need to place them with the correct side to each other and lightly press until they click.

Now, having secured the terminal blocks to each other and installed them on the rail, we connect the electrical wires to the structure. We recommend, depending on where what type of cable is and where it goes (to the board, light, stove, etc.), to mark them as in the photo with a color or number. At the end of the work, we check the connections, if necessary, treat them with anti-corrosion paste (for example, if the unit is located on the street) and use it.

Photo - Terminal block designation

Regardless of whether you connected the neutral wires or not, it is very important to secure them with a fuse - this will protect you and your equipment from unexpected power surges.

In addition to the described option for connecting terminal blocks, you can also immediately buy ready-made combs, which you simply need to snap onto the DIN rail.

Photo - terminal blocks

Recommendations for selection

In order to choose the right pad, you should adhere to the following rules:

1. Determine the functional purpose of the component.
2. Take into account the cross-section of the conductor and its quantity.
3. Select the method of installation work.
4. After the above provisions , it is necessary to decide on the most optimal model.

Particular attention should be paid to the characteristics of the plate, which conducts electric current. The base shows the maximum value, which is measured in volts. It is these restrictions that determine the type of conductor.

Wire connection process

In order to connect the wires yourself at home, you need to purchase the following equipment:

• terminals.
• wire, or as experts call it, twisted pair, which has 8 cores and varies in colors: emerald, brown, azure, carrot;
• a sharp knife to strip the wire;
• cable crimping tool;
• curved screwdriver;
• drill;
• installation box;

In order to properly connect the outlet, you need to perform certain steps step by step:

1. Cut the ends of the wire using a sharp knife.
2. We clean the wire with a blade.
3. We put all the wires parallel to each other.
4. Secure the wires with a ferrule so that the wires protrude approximately 1 centimeter.
5. Insert the tip into the terminal and secure with a screw.
6. Run the wire along the floor (if necessary, you can hide it in a box or ready-made strobes);
7. If the cable is hidden , you should install a box for installation (using a drill, make a small hole in the wall into which the box should be installed, using self-tapping screws and dowels);
8. With an open wiring method , mount the cable to the wall using brackets or using a plastic box.
9. After the above steps , we connect the electricity and check that all elements are connected correctly.

If the work is completed, but the connection to the electrical network has not occurred, you should check the quality of the work performed. To avoid this problem, you should work with a special cable tester.

After a positive result of checking the electrical connection, you can begin fixing the socket. Be sure to carefully place the cable in the box, and then attach the socket with screws. At the end of the work, you can decorate the rosette with a decorative overlay.

Terminals for connecting wires

Considering all the connecting terminals for wires produced by the industry, you should immediately make a reservation and divide the products into two types: electrical and electrical.

In fact, the difference (in current load) between the types is often small, but it still exists. This point should be kept in mind when selecting electrical terminals for installation, repair or other actions.

When faced with the need to select electrical terminals for wires, it is better to start with the simplest designs of domestic production - reliable, durable, proven in practice more than once:
1. knife;
2. fork;
3. ring;
4. pin;
5. couplings

Connections when constructing electrical circuits can be made using different methods, and terminals are just one of the options. However, this option seems to be the simplest, most convenient and even economical compared to, for example, soldering and welding, including cold welding.

Knife

These are perhaps the most common design options for products. They can often be found as part of the electrical circuits of many household appliances: irons, refrigerators, heating devices, etc.

But they are not intended for connecting conductors of power electrical wiring, for example, in residential electrical panels.

It is permissible to install this type of electrical products on conductors (multi-core) with a cross section of 0.26-6.0 mm2 by force crimping the shank.
There are two types of such products: insulated and non-insulated. The insulation is usually painted in different colors (red, blue, yellow) depending on the rated power of the terminal block. Products are used in pairs in a “father-mother” combination.

Fork

Fork-type terminals are designed for switching power and secondary circuits. These lugs are designed for subsequent fastening with screws directly to equipment or busbars. The instructions advise using them as a temporary contact or requiring frequent reconnection.

The design of the fork ends is a two-pronged fork, hence the name. This design allows for fairly simple switching without completely unscrewing the screw clamp. At the same time, when connected, it provides a fairly tight contact.

Fork lugs are available for wires with a cross-section of up to 6 mm2. The wires are attached to the terminals using the crimping method. This place, in various variations, may or may not have an insulating coating.

Ring

More reliable contact is provided by so-called ring terminals. Like their fork counterparts, they are designed to be subsequently secured with a screw clamp. But thanks to the round shape of the contact part, they provide a larger contact area and reduce the risk of tips “popping out”.

Ring terminals for wires are such a good solution that they are used not only in low-current networks, but are also a mandatory attribute of power cables of any cross-section. In this case, the method of attaching a wire or cable to lugs of this type can vary from welding and soldering to crimping.

Ring terminals are available in copper, aluminum, brass and copper-aluminium. Their cross-section can vary greatly, starting from small terminals for a C-grade screw and ending with bolts of 27 or more. In this case, terminals for low-current networks can be supplied with insulated crimp part.

Pin

This group of connecting terminals for electrical wires is made according to the principle of a detachable part, consisting of two separate elements - a plug and a socket. The plug is marked with the symbol “A”, for example, F2A.

The socket is marked with the symbol “B”, for example, F2B. Mounting on conductors with a cross section of 1.25-6.64 mm is supported. The main purpose of pin terminals is to ensure the connection of electrical conductors.

This group of mounting accessories refers to insulated products. The tail part of the terminals is covered with insulating material. Depending on the design power of the terminal block for connecting the wires, the insulator is colored accordingly.

Insulators of electrical terminals for conductors with a cross section of up to 2 mm2 are painted blue, the rest (from 2 to 6.64 mm2) are painted yellow.

What is a terminal block

A terminal block, screw clamp or terminal block is a special device that is used for electrical connection of wires; it is much safer than twisting. They are mainly necessary so that electrical cables can be tightened without damaging them.

Photo - Connecting terminal blocks on a DIN rail

The cable can be secured directly under the head of the screw, or force-tightened using a plate and screw connection (hence the name), or for more complex or delicate connections, pipe and screw technology is used. This device is very convenient because it can be used to create a completely sealed wire connection without damaging its contacts. For special cases, the cable can be inserted either into a special terminal block lug, which is then inserted into a terminal or electrical cabinet, or attached to connecting lugs, which in turn are fixed under the screw head. Such electrical devices are called walk-through devices.

Photo - Ground-zero terminal block

What is the best way to reliably connect two cables together?

Methods of connecting cables that require equipment and skills in the field of electrical engineering:

• soldering;
• welding;
• crimping with sleeves.

Simple connection methods that do not require tools or knowledge:

• connection using terminal blocks;
• spring clamps;
• PPE caps;
• bolted connection.

The choice of connection method depends on the characteristics of the wires. It is necessary to take into account the type and material of the core, the number of wires, and operating conditions.

With soldering

Soldering is a common method of connecting cables. To work you need a soldering iron, rosin, solder and sandpaper. How to connect wires by soldering:

• stripping of insulation;
• cleaning from oxides using sandpaper;
• the conductors need to be tinned - rosin is placed on the wire, it is heated with a soldering iron until the wire is covered with rosin;
• the conductors are assembled together, bubbling rosin must be applied to them and heated until the solder spreads;
• The soldering area is cooled.

The complexity of the process lies in the availability of professional skills. Do not overheat the solder area or twist it when heating, otherwise the insulation may melt. It is important to ensure high-quality and reliable contact of the wires. Soldering is used in low-current electrical applications.

No soldering

Wires are connected without soldering using special connecting elements. It is also possible to connect the wires by twisting. Twisting is the simplest method that does not require equipment, but this method is also the most unreliable.

It is prohibited to use only a twisted connection according to the rules of the PUE.

Copper

Copper wire can be connected using terminal blocks, Wago clamps (necessarily using special paste), using a bolt, or soldering.

Aluminum

Aluminum wires can also be connected using any method, but with some special features. When connecting, the metal must be manually stripped of insulation.

Copper and aluminum wires cannot be connected directly. The connection point becomes very hot and over time the contact weakens. Therefore, it is better to use terminal blocks, wago, bolt connection or special branch clamps.

Screw terminals

The electrical connector can be a screw type. Such contactors have been used for a long time. This type of terminals has certain disadvantages and advantages. These are compact, easy-to-install devices. They allow you to connect wires of different diameters. Moreover, they can be used for both single-core and multi-core conductors. In the second option, the end of the cable is stripped and crimped with brass lugs.

The disadvantage of this type of connection is the inability of the terminals to connect more than three conductors at the same time. This complicates the work somewhat, forcing you to make more connections. Also, over time, such a connector loses its original characteristics. The wires no longer fit tightly together. Therefore, when using a screw connection, you periodically have to tighten the junction of the wires.

For large diameter wires, connections are used, popularly known as “nut”. Such contactors are most often used when connecting wires from the carrier line to the house.

How to connect the wiring

The way the two wires are connected depends on many factors. The metal of the conductor, the thickness of the wiring, the number of cores and the type of insulating material should be taken into account. An important factor is the conditions under which the connection will be operated.

There are several main types of connections:

• traditional twisting using insulating material:
• wire welding , which requires the use of a special device;
• soldering of conductors , suitable for devices during operation of which excessive heating does not occur;
• crimping using sleeves >;
• use of bolted contacts guaranteeing reliable connection of conductors of different metals;
• connecting wires with terminals and terminal blocks of different shapes.

Each specific connection uses its own terminal

Let us consider in detail the main characteristics of all these compounds.

Features of professional twisting

Twisting is the simplest method of connecting wiring. The work does not require any special tools, just a knife and pliers. To ensure a strong connection, experts recommend stripping the wires by at least 5 cm. To ensure tight contact, the wires are clamped with pliers and twisted in a rotational motion. Afterwards, the resulting connection is wrapped in one direction and tightly wrapped with electrical tape. This is the simplest version of such a connection.

Professional electricians have other ways to connect wires by twisting:

Twisting options

Important! If you use electrical tape, don't skimp on the wrapping. The insulation should cover not only the twist itself, but also extend onto the wires by at least a couple of centimeters.

Instead of electrical tape, you can use a modern material - heat-shrink tube. Before connecting the conductors, heat shrink of the required length is placed on one of the conductors and then pulled into a twist. All that remains is to momentarily bring a match or lighter to the tube, it will shrink and tightly fix and insulate the veins.

The heat shrink material shrinks under temperature influence

With reliable insulation, such a connection will last quite a long time. Its advantage is good vibration resistance, which is good for moving mechanisms. Electricians do not recommend using this method when connecting wires of different sections. During operation, excessive resistance heats up the contact point so that the insulating layer can melt. Professionals do not recommend twisting wires with cores made of different metals and cables with a large number of cores.

Soldering for perfect conductivity

Not only the flawless operation of the mechanism, but also the safety of its user depends on the reliability and strength of the connection of the conductors. Soldering is one of the most reliable types of connections.

There is a soldering iron in almost every home, and the procedure itself does not take much time

Rosin is used for tinning, and tin or other fluxes are used as solder. It is recommended to solder copper wires with tin or lead, aluminum wires - with zinc compounds with tin, aluminum or copper. Before soldering, the wires are stripped and twisted using one of the above methods. Afterwards, rosin and flux are applied to the twisting site with a soldering iron.

Important! The heated solder should fill all the irregularities and holes in the twist.

After soldering, the connection is insulated with tape or heat shrink. The most difficult thing to solder is aluminum wiring. It oxidizes quickly at high temperatures and does not provide a strong connection to the solder material. For a strong connection you need to use tinning.

If soldering is done correctly, contact should be good. The only drawback is the fragility of the connection; under vibration and mechanical loads it will not last long.

For professionals: welding

Welding allows the metal of the conductors to fuse together and provide optimal resistance. This contact is strong and durable.

The only drawback of the connection is the need to use special equipment - a welding machine

Arc, spot, torsion, plasma, ultrasonic and beam welding can be used.

Such work requires experience and dexterity, so the welding method is a tool for professional electrical installers. They use graphite and carbon electrodes, operate stationary and use high-precision voltage-regulated inverters. This technique is not suitable for domestic conditions; only experienced welders know how to correctly connect the wires to each other in such a complex way.

Important! All welding work must be carried out wearing a protective helmet. It will be very difficult for a beginner to achieve a high-quality connection of conductors.

After welding, the contact area is also insulated with tape or heat shrink.

Crimping with sleeves

Returning to methods of connecting wiring that are more accessible for household use, it should be noted that crimping is a simple and accessible method that can be used without special skills.

The sleeve connection is characterized by high strength and resistance to mechanical stress

The technique is very simple - wire strands are inserted into a metal sleeve and then the soft metal is crimped using pliers or a vice. It is best to use special pliers for this purpose. They can manually crimp sleeves with a cross-section of up to 120 mm². If a larger sleeve is required, use hydraulics. The disadvantage of the sleeve connection is that it is final, and, if necessary, it will not be possible to correct the contact without cutting the wire.

For your information! For crimping, sleeves should be selected from the appropriate material to ensure optimal contact. There are sleeves made of aluminum, copper and alloys. The cross-sectional diameter of the conductor is also taken into account; the conductors must fit tightly into the sleeve.

The use of terminal blocks for connecting wires

The easiest and most reliable installation is using terminal blocks.

These simple and at the same time reliable devices are confidently replacing other switching methods

Wire terminal clamps can be used when installing conductors made of different metals. At the same time, the design of the terminals allows us to avoid direct contact between aluminum and copper and the formation of corrosion that is inevitable for such a connection.

Terminal blocks are divided into three main types: blade, screw and spring. As a rule, brass alloy is used as the main material. Some models are filled with a gel that protects the contacts from corrosion.

What is wire twisting and why is it dangerous?

Several decades ago, when the load on electrical wiring was not so great, such a connection was popular. Moreover, experienced craftsmen taught me, then a young electrician, to first thoroughly strip the metal cores, twist them tightly, and crimp them with pliers.

The length of this twist had to be created on the order of 10 cm to ensure good electrical contact, as shown in the lowest example. And they would reject anything higher, despite its beauty.

Inside closed, dry rooms, such twists worked for years and decades. However, many electricians violated the technology and created poor-quality contact.

In addition, in a humid environment, the metal oxidizes. The electrical resistance of its transition surface layer deteriorates. This leads to increased heating of the cores and premature damage to the insulation.

Therefore, modern rules, in particular the PUE (clause 2.1.21.), simply twisting wires is prohibited, no matter how beautifully and reliably it is done.

Particularly dangerous are twists of aluminum wires, as well as cores made of different metals - copper and aluminum.

This is due to the high ductility of soft aluminum and its high ability to create, under the influence of atmospheric oxygen, an outer layer of oxides that protects the internal structure of the metal. This film reduces conductivity.

When currents flow with increased loads, aluminum, which has a high coefficient of linear expansion, heats up, increasing its volume. After cooling, it contracts, breaking the tightness of the joint.

Each heating and cooling cycle degrades the electrical performance of the strand. In addition, copper and aluminum work as a galvanic couple, and these are additional chemical reactions with the formation of surface oxides.

My recommendation: wherever you find a simple twist, get rid of it. Reinforce it by soldering, welding, crimping or any other approved method.

Contact location and purpose

Terminal blocks are used for various wire connections. In some places you just need to splice the wires, somewhere you need to make a parallel connection, somewhere you need to apply the same potential to a large number of conductors. In principle, everything can be done with any type of block, but there are also special ones.

Terminal blocks can be designed for different numbers of wires. Minimum - two. The maximum is 48, but can be found with a larger number of outputs

Passing

Terminal blocks designed for pairwise splicing of wires are called feed-through terminal blocks. This is the most common type and it is what we have been talking about all the time. A contact plate is sealed in the housing, to which conductors are connected on both sides.

How to make a parallel connection using a feed-through terminal block

If desired, they can be used to organize a parallel connection. To do this, you need to put jumpers on one side and feed there the one of the cores to which you need to connect the rest.

Barrier view of the terminal block

One of the subtypes of feed-through terminal blocks is barrier ones. They are also designed for splicing wires, but their housing is designed in such a way as to prevent accidental contact of wires located next to or opposite.

Grounding and grounding

Grounding and grounding terminal blocks are produced separately. They are also called tires and are easy to distinguish by their appearance. This is a metal busbar with screw terminals. Often - on dielectric stands, painted in appropriate colors: grounding - green or yellow-green, neutral (zero) - blue. The corresponding wire is supplied to such a block. The metal tire “distributes” it. So then any conductor connected to it also becomes “zero” or “ground”.

Grounding and grounding terminal blocks

Grounding blocks usually do not have a housing, but only mounting feet. But, if desired, you can find it not only with a body, but also with covers. The number of connection points varies - from ten to several dozen.

Difference between terminal blocks according to the type of wire connection

There is another classification of products according to the type of wire connection. The most popular of them:

• Feed-through terminal blocks fix wires coming from different sides;
• barrier models are equipped with jumpers with screws placed in a dielectric housing;
• parallel connection of several wires is performed using cross-modules;
• The mechanism of detachable terminals for connecting wires has two sides. One side is equipped with connectors, and the other is equipped with a terminal connection;
• in end terminal blocks, the cores are fixed on one side only.

The housing of each terminal block is made of dielectric material. For the contacts themselves, copper or alloys are used. Some models may contain metal plates. Tinned contacts are considered the highest quality. They can be recognized by the silvery color of the tin.

Specifications

Even such a simple product as terminal blocks must be selected taking into account their technical characteristics. There are very few of them, but they are worth remembering.

• Rated voltage. Most of the terminal blocks are designed for a voltage of 400-450 V. That is, they can be used in both single-phase and three-phase networks. There are also special terminal blocks for low-current networks, but more often they use regular ones.
• Type of conductors. Not all types of terminal blocks are designed to accommodate all types of conductors. Usually the problem does not arise with the connection of single-core (solid-core) conductors or low-core rigid ones. But not all are suitable for soft and flexible multi-wire ones. This must be specified separately.
• Cross section of connected wires. Sockets for connecting conductors can have different sizes. The larger the cross-section, the larger the size of the nest. But not only. As the cross-section increases, the possible current load also increases. So manufacturers also monitor the dielectric properties of the case.

  Convenient to connect multiple wires

• Temperature range. Typically, this parameter is not very relevant for the private sector. Except if you are going to do the installation outdoors. Then you need to make sure that the plastic of the case is frost-resistant.
• Number of pairs or connected conductors.

That seems to be all the technical characteristics that are worth paying attention to. You also need to choose a manufacturer. This is where you shouldn't save money. Choose not by price, but by reliability. Because it is a poor-quality connection of wires in electrical wiring that often becomes the cause of a fire. So here, really, you only need to pay attention to quality.

Review of manufacturers and costs

WAGO terminal

Currently, trading enterprises present a wide range of terminals, which differ in price category and material base.

The most popular manufacturers are:

1. WAGO . They are the most popular on the trading market due to their reliability and good quality. Long period of operation. It is characterized by high cost. High-quality material is used in the manufacturing process.
2. ABB. Wide price range, which depends on the quality of the required part.

The terminals have a wide price range, which is set by the manufacturer.

For example, WAGO and ABB have the following options in their product range:

1. WAGO1+1 (for single-core or stranded conductor). Cost 12 rubles.
2. WAGO 2 (solid or stranded conductor). Cost 15 rubles.
3. WAGO 5 (designed for single-core or stranded conductor). Cost 30 rubles.
4. ABB 10/10 R terminal block Cost 126 rubles.
5. ABB 10/10 R terminal block Cost 115 rubles.
6. Navigator terminal block. Cost 134 rubles.

Before choosing terminals, you should pay attention to the type of installation work and workmanship. This will help to avoid defects in the process of transmitting electrical energy through conductors, which guarantees a long service life of the component.

LEGRAND

Screw switches from this manufacturer are the most popular product in this category. Brass products are coated with nickel and can reliably withstand powerful temperature changes. These terminals are highly durable and have a wide range of sizes.

To make it easier to distinguish wires during installation and operation, the terminals are made in different colors

WAGO

The products of the French company guarantee a strong connection of wiring of different types and cross-sections. The devices perfectly resist possible vibration and stretching and are installed without special tools. The main material of French terminal blocks is tinned copper, which gives good contact with low resistance. Some models are filled with anti-corrosion gel.

The WAGO product range allows you to choose a product for any task

WIEDMULLER

Another European brand offers one and a half hundred models of terminals. The core of the range is made up of screw connections made using DIN technology.

WIEDMULLER terminals

PHOENIX CONTACT

The German manufacturer is distinguished by excellent product quality. It offers more than 200 types of different switches for different types of connections. Among the presented models there are resistant to high humidity and explosion hazard.

PHOENIX CONTACT terminal blocks are highly durable

General installation requirements

The quality of connections and branches during installation is of paramount importance. When troubleshooting an electrical circuit, most often the problem occurs due to a lack of contact.
Poor contact can lead not only to a circuit break, but also to overheating of the wires. This is often the cause of fire. Therefore, strict requirements are imposed on them.

Regardless of which terminals are used for installation, the following rules must be followed:

1. During installation, it is necessary to leave a reserve of wires before all connections (for reconnection).
2. All connections must be located in accessible places.
3. The location of the connecting elements must be protected from vibration and any other mechanical influences.
4. The insulation of the connecting elements must match the insulation of the conductors.
5. All connections must be made in junction boxes, cabinets and control panels, and special niches in building structures.

There are many types of terminal blocks available for different purposes:

• plug-in;
• hybrid;
• mini and micro terminals;
• fuse terminals;
• disconnect terminals;
• multi-pin;
• multi-tiered;
• checkpoints and others;

For all varieties, the installation rules are the same.

Common problem: how to connect aluminum and copper wire

Residents of Soviet-built houses often face this problem. At that time, almost all wiring was done using aluminum conductors. Modern electricians mainly use copper wire. How to connect aluminum wire to copper? There are skeptics who claim that such a connection is impossible. You shouldn't believe them. If you correctly use the techniques that we present below, the switching will be reliable and durable.

As already mentioned, ordinary twisting will not work for such a connection. The contact between copper and aluminum gets very hot and can damage the insulating layer.

Option 1 – bolt-on

This is a simple and affordable method that uses steel nuts, bolts and washers. Due to the impressive dimensions of such fasteners, it is unlikely to be placed in a modern small junction box. But such switching allows you to combine wiring not only from different metals, but also with different cross-sections. Such connections are easy to disassemble and reassemble if necessary.

Video recommendations for bolted connections:

Option 2 – “walnut” connection

The name of this connection was invented by electricians because of its external similarity. For fastening, use a special crimp, which is sold in electrical goods stores. The device consists of two dies with grooves for conductors. After fixing the cores, the dies are wrapped with electrical tape.

In practice it looks like this:

Option 3 – terminal switch

Easy to install and reliable connection option. The block is selected in accordance with the cross-section of the wires. Serrated fasteners ensure reliable fixation of the cores. It must be remembered that aluminum does not like screw connections, so you will have to periodically check the contact without waiting for it to loosen.

Recommendations for installing the switch:

Spring leads for dissimilar wires

Connectors for wires made of different materials can be of the spring type. They also help to eliminate direct contact between the cores. They can be detachable or non-detachable. One of the most famous and reliable ways to connect copper and aluminum cables is the Wago universal connector. The cross-section of the cores when using it can also be different.

Permanent wire connectors use the screw terminal principle. You can also use devices in which the metal plate is replaced by a special conductive rod. It is riveted to provide a secure connection. Exposed sections of the cable must be additionally insulated.

Having considered what types of wire connectors exist, as well as their characteristic differences, everyone will be able to choose the best option for connecting various devices or carrying out repair work.