How to properly connect aluminum wires

How to connect aluminum wires to each other - electrician's advice - Electro Genius

Electrical wiring in almost all old apartments and houses is made of aluminum. Therefore, when independently performing electrical installation work to move sockets or when repairing distribution boxes, you often have to connect aluminum conductors to each other.

All electricians will agree that aluminum wiring is very capricious in terms of connection: the core often breaks during installation, especially if the wire is quite old. Therefore, it is important to choose the right method to ensure a reliable and durable connection. In this article we will look at the main methods and technologies.

Soldering method

Soldering aluminum wires is considered one of the most reliable connection methods. In addition to reliability, this technology is simpler than, for example, welding. However, soldering aluminum wires is not as easy as copper wires. The reason for this is the unique ability of aluminum to oxidize almost instantly in air, forming a film that interferes with the normal application of solder.

Therefore, the process of soldering aluminum is quite labor-intensive and requires certain knowledge and skills. To connect aluminum cores to each other using soldering, a mechanical method is used to remove the oxide and simultaneously apply soldering acid to the cleaned areas. Let's take a closer look at this process.

Soldering technology

As a rule, the electrical wiring in the apartment is made with a single-core wire. This is the option we will consider. So, to solder two aluminum wires together, you need to follow the following instructions:

• The conductors are stripped of approximately 4–5 cm of insulation. You must act carefully so as not to damage the metal;
• Then the bare ends are treated with fine sandpaper and twisted together. It is important that the wires wrap around each other. It is better to avoid winding one core onto another: such a connection will be of poor quality and it will not be possible to solder it;
• The resulting twist is processed again with sandpaper, after which a little soldering acid is applied to it. This aggressive substance prevents the oxide film from forming again;
• The twist grooves are then carefully filled with molten solder. Thanks to the acid, the solder adheres well to aluminum;
• At the end of the twist, a small thickening of solder is usually made so that the ends do not cling during installation.

After the connection is made, the working surface of the wires must be treated with alkali and washed with water to remove any remaining acid. Otherwise, the acid will continue to eat away at the insulation and metal.

After drying the solder joint, they begin to isolate it. For these purposes, use cambrics, caps or regular electrical tape. Additionally, you can treat the twist with waterproof varnish if it is intended to be used in a humid environment.

Welding Application

Another method that ensures a high-quality and reliable connection is welding aluminum wires. This method is more difficult to implement in practice than soldering.

To make a connection by welding, a special powdered flux is used, which must be diluted with water to a thick paste before work.

In addition, a special low-voltage welding machine is required, as well as special knowledge and experience.

We will look at the general technology of how aluminum wires are connected to each other using welding:

• The ends of the wires are freed from insulation by 4–5 cm.
• The cores are twisted together.
• Paste-like flux is applied. It can be applied with a brush or immerse the wires 3–5 mm in a container with the composition.
• After this, an electrode is brought to the ends of the twist and welding is performed for 1–2 seconds, after which the electrode is removed.

Thanks to the applied flux, oxygen does not reach the aluminum, and the electrode does not stick to the molten metal. As a result of these manipulations, you should get a neat “drop” of molten aluminum at the end of the twist, through which current flows freely between the wires. The twisting itself ensures a reliable connection of the conductors.

In most cases, the method of welding aluminum wires together is used in industry, as well as for connecting powerful cables of large cross-section.

Mechanical connection methods

In addition to soldering and welding, there are other widely used methods for connecting aluminum wires. This is the so-called mechanical connection, most often performed using screw blocks or other similar devices.

Terminal blocks

Such blocks with screw terminals are widely used not only in switchboards, but also in distribution boxes in apartments and houses. They are reliable and provide good contact.

To connect wires subject to heavy loads, it is better to use branded connectors made of black impact-resistant plastic. In them, the aluminum core is clamped with a small square plate, which prevents damage to the core. Terminal blocks made of white plastic are suitable for connecting wires with a small cross-section, for connecting low-power consumers.

Self-clamping terminals

Self-clamping terminals and blocks from various manufacturers have become very popular for household use. Such devices can be either detachable (reusable) or non-detachable (disposable).

Inside the plastic case of such a device there is a metal clamping plate that secures the wire and ensures good contact with the conductive busbar. The housing can be made of black or colored plastic, and transparent terminal blocks are also available.

Self-clamping terminals have from 2 to 8 connectors, which allows you to make various connections, as well as electrical wiring branches.

Crimping method

If you need to connect several single-core wires or a multi-core cable into one connector of the block, you can use special crimp sleeves.

The stripped ends of the wiring are inserted into an aluminum or copper sleeve. And the sleeve itself is crimped with special pliers: the result is reliable contact.

This method is often used when connecting several powerful consumers, as well as for connecting wires to each other.

Instead of a simple sleeve, you can use special NKI tips. They have a small crimp sleeve at one end into which the wire is inserted. At the other end there is a slip ring that allows for a simple and reliable connection to the screw terminal block.

Connection using a bolt

Sometimes two or more aluminum wires are connected to each other using a regular bolt and nut. To do this, make a circle around the bolt from the stripped ends, place them between the washers and tighten with a nut - the connection is ready.

Let's sum it up

We looked at several ways to ensure a reliable connection and good contact between aluminum wires. Some methods will require special equipment, knowledge and experience. And in some cases, you can get by with improvised means.

Source: https://orenburgelectro.ru/baza-znanij/kak-soedinit-alyuminievye-provoda-mezhdu-soboj-sovety-elektrika.html

How to properly connect aluminum wires to each other? — Website about

Connection of aluminum wires

How to connect two aluminum wires to each other? It would seem like a rather banal question, but even here the first answer that comes to mind is not always correct. After all, twisting of wires is prohibited according to the PUE standards, and any wires can be connected only by crimping, soldering, welding and using screw clamps. And we’ll talk about how to do it correctly in our article.

Properties of aluminum wires

But we propose to start our conversation with a quick analysis of the properties of aluminum wire. This will allow you to identify problem areas and understand possible problems during its installation.

Comparison of copper and aluminum wire

• Let's start with the advantages of aluminum wire. The main one is the price, which is an order of magnitude lower than that of its main competitor - copper.
• Another advantage of this material is its lightness. This has led to its widespread use in power lines, where weight is very important.
• Well, the last advantage is its resistance to corrosion. Aluminum is almost instantly coated with a persistent oxide film, which prevents further oxidation. At the same time, this film also has negative aspects - it is a very poor conductor of electric current.

Areas of application of copper and aluminum wires

• Then there were only continuous shortcomings. And the first of them is the low electrical conductivity of aluminum. For this material it is 38×106 S/m. For comparison, for copper this parameter is 59.5 × 106 S/m. This results in the fact that, for example, a copper wire with a cross-section of 1 mm2 is capable of passing a current almost 2 times greater than a similar aluminum wire.

Resistance of some substances

• The next significant disadvantage is that aluminum wires have very low flexibility. In this regard, they cannot be used in places where the wiring is subject to repeated bending or other mechanical stress during operation.
• Well, and finally, the instructions say that aluminum has such a bad property as fluidity. As a result of thermal and mechanical influences, it can lose its shape, which has an extremely negative effect on contact connections.

Note! According to the PUE standards, since 2001 it has been prohibited to use aluminum wire for installing electrical wiring in residential premises. This ban significantly reduced the use of aluminum electrical wiring in everyday life.

Methods for connecting aluminum wires

As we said above, aluminum wires can be connected in four main ways - screw or bolt clamps, pressing, welding and soldering. Let's look at the features of each of these types of connections.

Connecting aluminum wires using the compression method

Let's start with the most common connection method - compression. It can be of several types - bolted, screw or using a pressure spring, which is used in Wago terminals.

The screw terminal may damage the aluminum wire	Connecting aluminum wires to each other using this type of connection has one drawback. If you use conventional screw terminals, then using a screw you can completely or partially press down the soft aluminum core. This will either reduce or completely destroy contact.
Brass lugs for aluminum wires	To exclude this option, the connection should be made through special contact nozzles made of brass. Brass has less elasticity and is more difficult to bend. Therefore, such attachments provide reliable contact and eliminate the possibility of damage to the wire.
Aluminum lugs for bolting wires and cables	For bolted connections of aluminum wire, special lugs should also be used. They are attached to a wire or cable using the crimping method and then these lugs are connected using a bolted method.
Wago terminals for connecting aluminum wires	As for Wago terminals, everything is much simpler here. This type of connection cannot damage the wire, so such terminal blocks can be used without additional attachments. This somewhat compensates for their higher price.

Connecting aluminum wires using the pressing method

Recently, connecting aluminum wires with a sleeve has become increasingly popular. This is partly due to the widespread use of crimpers or, as they are also called, crimping pliers. This tool allows you to crimp wires of different sections, ensuring fairly reliable contact.

Crimpers for crimping wires

Sleeves for connecting aluminum wires

• The connection of wires by crimping is carried out using special sleeves. These sleeves are available in different diameters and materials. To connect aluminum wires, either aluminum or brass sleeves should be used. Copper should not be used under any circumstances, since the connection of these two materials can lead to the formation of galvanic isolation and ultimately the complete destruction of the aluminum conductor.

Note! The cross-section of the sleeve for connecting wires must correspond to the cross-section of the wire.

If you use a sleeve with a smaller cross-section, then to insert the wire into the sleeve you will have to reduce its cross-section, which will negatively affect the contact.

If you use a sleeve with a larger cross-section than the wire, then the area of ​​the contact connection will be much smaller, which again will lead to overheating of the contact.

Sleeves for connecting wires of different sections

• To connect wires of different sections, there are sleeves with different diameters of the inlet holes. They can also be used to connect more than two wires in one sleeve.
• Sleeves for connecting aluminum wires have a strictly required length. Believe me, the manufacturer did not make a reserve in the sleeve, so cutting the sleeve in half in order to save money is a very bad option. After all, when connecting two wires, crimping should be done twice with opposite crimps. If you cut the sleeve in half, you won't be able to do this, and the contact will be poor quality.

• Another frequently asked question relates to connections between stranded aluminum wire and solid wire. It is possible to make such a connection using crimping, and it will be of sufficient quality. The main thing is to choose a sleeve with the appropriate inlet diameters. Indeed, in most cases these are wires of different sections.

Connecting aluminum wires welding method

The best quality of connection is ensured by welding. Due to the fact that in this case the wire forms a single whole, problems with transition resistances, the possibility of reducing the pressure force, and much more are practically eliminated. But there are also a lot of problems here.

Welding aluminum wires

• The fact is that, as we said above, an oxide film forms on the surface of aluminum. It has completely different heat and electrical conductivity than aluminum itself. In this regard, welding aluminum wires is difficult.
• Since the melting temperatures of oxide and aluminum differ, attempts to simply weld wires with a carbon electrode will not be very successful. Oxides will remain on the molten drops of aluminum, and the compound itself will not be homogeneous, as in the video.

The photo shows the process of welding aluminum wires

• To eliminate this problem, you can remove oxides from the surface mechanically, but this is labor-intensive and not always effective, since the formation of a new film occurs almost instantly.
• Based on this, in most cases, various fluxes are used for welding, which can destroy the oxide film. This material should destroy the oxide film and practically not react to pure metal; in addition, it should not produce harmful compounds during welding. Selecting such material is quite difficult and often you have to make a compromise.

Wire welding technology

• But even with the use of fluxes, it is quite difficult to make a welded connection of wires with your own hands without proper preparation. This is due to the fact that it is extremely important to select the proper welding voltage (usually no more than 20V) and exposure time to the conductor (usually 1-2 seconds).

Note! In addition to electric welding of aluminum wires, gas welding is also quite common. It has its own characteristics regarding both the materials used and the welding temperature.

Connecting aluminum conductors by soldering

The last option that can be used to connect sockets with aluminum wires is soldering. This method is quite labor-intensive and can hardly be called fast.

Therefore, it is used extremely rarely for power plants, and in low-voltage networks, aluminum wires are used quite rarely due to their rigidity. Nevertheless, let's consider this option.

Soldering aluminum wires

• The main problem here, as in the case of welding, is the oxide film. In addition, there is such a problem as the lack of visual control over the temperature of the wire. Indeed, with prolonged exposure to high temperatures, aluminum can change its physicochemical properties.
• Based on this, the process of soldering aluminum becomes quite complex. First of all, we need to get rid of the oxide on its surface. This can be done using any abrasive materials, but you should not be zealous, since a new film is formed almost instantly. Our task is only to reduce its thickness.

• After this, the wires are fixed and solder and flux are touched to the wires. It is better to use TsOP-40 or its analogues as solder.
• Flux for soldering aluminum is F - 59A, F - 61, F - 34 or other similar compositions. They destroy the oxide film quite well.

Solder for soldering aluminum

• When the solder touches the wires, they should be scraped across them to make it easier for the flux to break down the oxide film. If soldering is performed without using flux, then the intensity of friction of the solder on the wires should be more intense.

Conclusion

Connecting aluminum wire with a sleeve and using terminals are the simplest options. At the same time, the use of crimping does not require additional materials, but requires the presence of a crimper.

Source: https://orensbyt.ru/elektrooborudovanie/kak-pravilno-soedinit-alyuminievye-provoda-mezhdu-soboj.html

How to connect aluminum wires to each other

In electrical engineering, a wire is a metal conductor that consists of one or more strands intertwined to transmit electricity.
The core through which the current passes may consist of one wire of different thicknesses or several at once. A stranded cable consists of cores of homogeneous material twisted together.

Wires based on only one core have significantly less flexibility than wires made from several cores. Electrical cables are made of copper and aluminum. They are made from the latter material to save money, since they are much cheaper. Aluminum cables are produced with a standard cross-section, only the smallest value is 2.5 mm2.

They also have different designs under the outer braid. They can go in pairs parallel to each other, twist with different turn periods, and so on. The wires can then be identified by their markings and insulation. The cores can be either bare or insulated with a special braid that does not allow electricity to pass through.

For insulation, rubber, vinyl plastic, and polyvinyl chloride are often used. For greater protection of the power cable, it can be placed in a cotton braid, which must be impregnated with a special composition that is anti-rotting and resistant to moisture.

In places where the core is subject to increased mechanical stress, it can be placed in a metal sleeve.

There are several designations for aluminum wires. A, AC, ASU - means that the cable is multi-wire, bare (without braiding), its cross-sectional area varies: 16-25 mm2, 16-40 mm2 and 120-400 mm2.

The last two designations indicate that the wire has a galvanized steel core. These types can be used for conducting overhead power lines.

 And also APRTO, APPV, APV - they classify aluminum wires with external braiding and different thicknesses.

Required Tools

In order to correctly connect the wires to each other or branch them, you need to have a good and high-quality tool.
It is advisable that each task has its own type of tool. For this type of work you will need:

• round nose pliers and pliers;
• pliers and crimping pliers;
• a set of special screwdrivers with insulated handles and bits;
• probe screwdriver;
• a roll of insulating tape.

Typically, the difficulty of connecting and branching aluminum wires lies in the fact that this metal has special properties. It is soft and bends easily, but at the same time it is not very strong, so it requires careful handling and more protective devices. If the wires come into contact with air, then this metal oxidizes quite quickly. When connecting it to a copper wire, you can observe how corrosion occurs, which eventually leads to destruction.

Connection options

There are many options for connecting aluminum wires to each other.

One of the most common methods is the usual twisting of stripped contacts. Most people who do not have special knowledge in the field of electrical engineering use this method to connect aluminum wires, considering it reliable.

This is a misconception. Not all types of cable can be twisted, since they may have different cross-sections, which will create a vulnerable spot in the wiring after they are connected, as well as different brands of these cores.

This method is not suitable for branching an electric line.

This method has a low level of reliability, as well as a high degree of fire hazard.

When this method existed, there was not yet such a large number of various household electrical appliances that consume a lot of energy (washing machines, air conditioners, water heaters, two-chamber refrigerators, etc.).

The simultaneous use of several powerful energy-intensive devices significantly increases the load on the network. Contacts with a small cross-section will not withstand increased voltage. For this reason, the twisting method has lost its relevance. It can be used for a temporary connection.

Soldering. For connecting or branching aluminum wires, this fastening method is considered one of the safest. To do this correctly, you need to tin the wire contacts. To do this, they are treated with molten rosin and then carefully sanded with fine sandpaper. Then the ends of the cables are pressed tightly against each other, and then rosin is gradually added. Soldering must be uniform to extend service life.

Welding. This connection method is not available to everyone. To do this, you need to have special knowledge and skills, have special equipment, to which not everyone has access. This method is very reliable, but is highly recommended for experienced welders.

Contact clamps. This method is best for connecting aluminum conductors. In the same way, you can follow the wire branches if necessary.

To do this correctly, you should strip the contacts from the braid by 2-3 centimeters, and then clean the metal using fine-grained sandpaper (0 and 1 grain is suitable). The exposed part will need to be rounded.

The cross-section of this circle should be similar to the diameter of the clamping terminal. The resulting circle is put on the mover and tightened tightly.

Among the contact clamps there is a spring type. It is simple enough to make a wiring branch or temporary connection of wires. It is enough just to clean the contacts and secure them with a spring mechanism.

A separate fastening method is connecting fittings or a SOAS-type clamp for steel-aluminum and aluminum cables. The oval SOAS clamp can be used to fasten two groups of wires: with a current load and mechanical tension along them, or only with a current load.

 Different brands of COAS clamp can be used depending on the wire brand, size, strength and weight. In addition to SOAS, the SAS type can be used to fasten steel-aluminum cores. For each type of such devices, there are special tables with corresponding indications and values.

SOAS-IP is used for overhead power lines. Bare wires can be connected by twisting using a SOAS-IP type clamp. The Oval OSA clamp is a fairly common type and can be purchased in most specialty stores, as well as ordered online.

Useful tips

When working with electrical wires, they must be de-energized, even if the voltage is not high. After completing the work, the exposed contacts must be insulated with special tape, placed in a rubber braid or in a protective sleeve. In masses with high humidity, the fastening will not last very long, and there is also a risk of getting an electric shock.

When working with the SOAS clamp, you need to use special devices and tools for twisting the wires together. You need to pay careful attention to the marking of the oval clamp of the OSA, since a discrepancy between the parameters can lead to unforeseen consequences.

Source: https://kanalizaciya.online/elektrika/elektroprovodka/kak-soedinit-alyuminievye-provoda-mezhdu-soboj.html

Connecting aluminum wires to each other: types of connections, how to tin and solder

Creating reliable electrical contact when installing a cable is not as easy as it seems. This is especially true for aluminum wires: due to the physical properties of the metal, problems may arise when connecting them.

Features of aluminum wires

Aluminum wires cannot be used in residential areas

According to the PUE standards, it is prohibited to use aluminum conductors during installation in residential premises.

Aluminum wire is a cheap solution, with a price that is an order of magnitude lower than copper wire. It is not subject to corrosion, as it is instantly covered with a thick oxide film. Has a low specific gravity.

The main disadvantage is the low electrical conductivity of aluminum. It is 37.9 μS×m, which is almost twice as bad as copper, which has 59.5 μS×m. The low flexibility of the conductor makes it impossible to install in places where it is subject to repeated mechanical stress.

There are four types of wire connections: crimping, squeezing, welding, and soldering. Crimping sleeves and terminal blocks will ensure easy and quick cable installation in places where high mechanical resistance is not required. Soldering and welding will provide the most durable and reliable connection, but require skill and the use of special tools.

Pressing method

Pressing is done using a special sleeve into which the cores are inserted, after which they are crimped with a special tool - a crimper. Sleeves vary in diameter, length and material. When installing the cable, only aluminum or brass sleeves must be used. Using brass elements, you can connect both aluminum to aluminum and copper to aluminum wires.

When connecting aluminum conductors, copper-containing sleeves must not be used. These two metals form a galvanic couple, which leads to accelerated destruction of aluminum.

To connect cores with different sections, special sleeves with different diameters of inlet holes are used.

The correct choice of sleeve diameter will protect the chain section from overheating. A larger diameter will give a small contact patch and increased resistance. If the cross-section of the sleeve is smaller, it is necessary to reduce the cross-section of the cores, which will also negatively affect the conductive properties.

Compression method

Wire compression terminal

When routing cables in a distribution box, accidental contact of adjacent wires is highly undesirable. Terminal blocks are used for this purpose.

The terminal is an insulated sleeve into which the conductors are inserted. Internally, either a screw or a spring is used for fixation.

If you intend to install a stranded wire, before installing it into the terminal it is necessary to crimp it with a special sleeve, which will improve contact and reduce the likelihood of pinching.

When using terminals with a screw connection, you need to clearly control the clamping force in order to avoid cutting the wire with a screw and its subsequent destruction. Wago terminal blocks do not have this drawback. In them, the mechanism for fixing the core is a brass plate and a spring. The use of brass in the composition makes it possible to safely connect cables made of different metals.

Welding method

When welding, a drop forms at the end of the twist

Welding provides the best electrical contact. Due to the homogeneity of the resulting connection, there is no problem of increased resistance of the circuit section.

A welding machine is used with an output power of up to 1 kW and an adjustable voltage within the range of 14-20 V. Welding is considered successful if a drop has formed at the end of the twist, with a diameter approximately equal to the twist.

When welding, a carbon conductor is used along the end of the twist. The exposure time should not exceed 2 seconds.

There is an option for gas welding of wires. In an inert gas atmosphere, the oxide film ceases to form, which significantly facilitates the process, but specific knowledge and equipment are required.

Soldering method

When welding wires, tin solder is used

Before tinning the surface, the oxide film is removed. This can be done either by mechanical force, for example, sandpaper or a brush with metal bristles, or by using a special chemical - flux. It is a white powder that dissolves in water and is then applied to the ends of the tinned wires.

Aluminum oxidation in air occurs in a matter of seconds, so mechanical action alone cannot remove oxides. It is recommended to combine the use of flux and surface cleaning.

If two wires are being soldered, using a 60 W soldering iron will be sufficient. For wires with a large cross-section and when soldering multi-core twists, you will need a soldering iron with a power of 150 W or more.

The tin content in the solder must be at least 50%. You can take solder with 60-90% content.

Soldering aluminum step by step:

• Degrease the surface. Gasoline and alcohol will do. This will thin the oxide film.
• Fix the wire strands in the required position.
• Apply flux. Make sure it hits the cable joint.
• Warm up the twisting area with a soldering iron or gas torch. In the latter case, you should be careful, as the metal heats up quickly and can melt.
• Tin the connection point. Gently rub the solder with a soldering iron until a homogeneous shiny film appears.

A properly treated surface acquires a characteristic metallic sheen. Sagging and untinned areas should not be allowed to appear.

Tin solder is susceptible to corrosion, so the finished connection is treated with varnish.

When extending wires, if operation is expected in difficult conditions, a soldered or welded connection will perform best. In everyday life, for cables that are not subject to mechanical stress, crimping with a sleeve is quite suitable.

Source: https://StrojDvor.ru/elektrosnabzhenie/soedinenie-aluminievyh-provodov/

How to connect aluminum wires to each other

Typically, in new generation houses, electrical wiring is made of cable with copper conductors, while in older buildings there may still be wiring made of aluminum wires. Sometimes it happens that it is not possible to dismantle the old cables by replacing them, and then you need to connect the aluminum wires to each other. For example, you may need to connect a lighting device in a room, replace a switch or install an outlet, then you need to know what to do.

In electrical engineering, a wire is a metal conductor that consists of one or more strands intertwined to transmit electricity.
The core through which the current passes may consist of one wire of different thicknesses or several at once. A stranded cable consists of cores of homogeneous material twisted together.

Wires based on only one core have significantly less flexibility than wires made from several cores. Electrical cables are made of copper and aluminum. They are made from the latter material to save money, since they are much cheaper. Aluminum cables are produced with a standard cross-section, only the smallest value is 2.5 mm2.

They also have different designs under the outer braid. They can go in pairs parallel to each other, twist with different turn periods, and so on. The wires can then be identified by their markings and insulation. The cores can be either bare or insulated with a special braid that does not allow electricity to pass through.

For insulation, rubber, vinyl plastic, and polyvinyl chloride are often used. For greater protection of the power cable, it can be placed in a cotton braid, which must be impregnated with a special composition that is anti-rotting and resistant to moisture.

In places where the core is subject to increased mechanical stress, it can be placed in a metal sleeve.

There are several designations for aluminum wires. A, AC, ASU - means that the cable is multi-wire, bare (without braiding), its cross-sectional area varies: 16-25 mm2, 16-40 mm2 and 120-400 mm2.

The last two designations indicate that the wire has a galvanized steel core. These types can be used for conducting overhead power lines.

 And also APRTO, APPV, APV - they classify aluminum wires with external braiding and different thicknesses.

“Connecting wires by soldering”

There are many options for connecting aluminum wires to each other.

One of the most common methods is the usual twisting of stripped contacts. Most people who do not have special knowledge in the field of electrical engineering use this method to connect aluminum wires, considering it reliable.

This is a misconception. Not all types of cable can be twisted, since they may have different cross-sections, which will create a vulnerable spot in the wiring after they are connected, as well as different brands of these cores.

This method is not suitable for branching an electric line.

This method has a low level of reliability, as well as a high degree of fire hazard.

When this method existed, there was not yet such a large number of various household electrical appliances that consume a lot of energy (washing machines, air conditioners, water heaters, two-chamber refrigerators, etc.).

The simultaneous use of several powerful energy-intensive devices significantly increases the load on the network. Contacts with a small cross-section will not withstand increased voltage. For this reason, the twisting method has lost its relevance. It can be used for a temporary connection.

Soldering. For connecting or branching aluminum wires, this fastening method is considered one of the safest. To do this correctly, you need to tin the wire contacts. To do this, they are treated with molten rosin and then carefully sanded with fine sandpaper. Then the ends of the cables are pressed tightly against each other, and then rosin is gradually added. Soldering must be uniform to extend service life.

Welding. This connection method is not available to everyone. To do this, you need to have special knowledge and skills, have special equipment, to which not everyone has access. This method is very reliable, but is highly recommended for experienced welders.

Contact clamps. This method is best for connecting aluminum conductors. In the same way, you can follow the wire branches if necessary.

To do this correctly, you should strip the contacts from the braid by 2-3 centimeters, and then clean the metal using fine-grained sandpaper (0 and 1 grain is suitable). The exposed part will need to be rounded.

The cross-section of this circle should be similar to the diameter of the clamping terminal. The resulting circle is put on the mover and tightened tightly.

Among the contact clamps there is a spring type. It is simple enough to make a wiring branch or temporary connection of wires. It is enough just to clean the contacts and secure them with a spring mechanism.

A separate fastening method is connecting fittings or a SOAS-type clamp for steel-aluminum and aluminum cables. The oval SOAS clamp can be used to fasten two groups of wires: with a current load and mechanical tension along them, or only with a current load.

 Different brands of COAS clamp can be used depending on the wire brand, size, strength and weight. In addition to SOAS, the SAS type can be used to fasten steel-aluminum cores. For each type of such devices, there are special tables with corresponding indications and values.

SOAS-IP is used for overhead power lines. Bare wires can be connected by twisting using a SOAS-IP type clamp. The Oval OSA clamp is a fairly common type and can be purchased in most specialty stores, as well as ordered online.

“We cook the wires with a torch”

If you don’t know how to connect aluminum wires using a gas torch, then the next video is for you.

Source: https://otoke.ru/provodka/provoda/soedinenie-alyuminievyh-provodov-mezhdu-soboj-444/

How to properly connect aluminum wires

Due to their lightness and reliability, cables with aluminum conductors have found wide application in laying various power lines. Before connecting aluminum wires in electrical wiring, it is necessary to determine the electrical problems to be solved and clarify the technical parameters of the product.

Where are aluminum wires used?

The ban on the use of aluminum wiring in residential premises was introduced more than fifteen years ago for fire safety reasons, but with the advent of new aluminum alloys, which are not inferior in characteristics to copper cables, the situation has changed radically.

The area of ​​use of the wire depends not only on the type of conductor, but also on the insulation material, as well as the design features of the product. Today, aluminum cables provide transmission and distribution of electricity in various stationary installations. In residential buildings, cables with an aluminum conductor cross-section of 16 mm2 or more are laid.

The undeniable advantages of aluminum cables are affordability, low weight and the formation of a persistent oxide film, while the disadvantages include fragility, low electrical conductivity, a tendency to oxidize and a relatively short service life.

How to connect

There are several options for the correct and absolutely safe connection of aluminum conductor cores. They differ in labor intensity and level of complexity, so in each specific case the connection method should be individually selected.

Soldering

One of the most reliable connection methods, based on the mechanical removal of formed natural oxides and the simultaneous application of soldering acid to the cleaned areas.

For soldering you need to purchase special solder

Soldering technology:

1. Carefully strip the core from the insulating layer by 40–50 mm.
2. Sand the bare ends with fine-grit sandpaper and twist them together.
3. Repeated processing of the resulting twist with sandpaper.
4. Application of soldering acid to the twist, which prevents the formation of an oxide film.
5. Filling the twist grooves with well-molten solder.
6. Treatment of joint areas with alkali and rinsing in water to remove acid residues.

The dried joint is treated with waterproof varnish, after which it is insulated with cambrics, caps or regular electrical tape.

Clamp connection (terminal)

The most common connection method. Compression involves the use of a bolt, screw or clamping spring connection method. It is optimal to use special Wago terminals.

Special terminals are often used to connect wires

Wago terminal connection technology:

1. Remove the insulating layer from the ends of the wires to a length of 10 mm.
2. Insert the bare ends into the round holes of the self-clamping type contacts.
3. Press the moving zone or lift the terminal lever.
4. Having advanced the wire, release the moving part or lock the lever in the lower position.

Self-clamping terminals for 2–8 connectors allow you to make connections and branches of electrical wiring of varying levels of complexity. You need to select a terminal or block in accordance with the marking, which reflects the cross-section and number of aluminum conductors.

You need to select terminals taking into account the cross-section and number of aluminum conductors

A traditional screw terminal can damage aluminum wires, so when using it, brass contact tips must be used.

Pressing

The method involves using special crimping pliers - crimpers and a brass or aluminum sleeve, the dimensions of which directly depend on the cross-section of the core. The connection obtained as a result of pressing is durable and reliable.

The sleeve size depends on the wire cross-section

Pressing technology:

• Decide on the size of the tip or sleeve depending on the cross-section of the core.
• Strip the ends of the wires to be connected with a stripper.
• Place the tip or sleeve on the conductive part of the cable, cleared of the insulating layer.
• Place the sleeve with the wire in the special groove of the crimping pliers and squeeze the tool handles.—

Depending on the design features, the tool can be represented by a manual hydraulic press and electrically driven pliers. Multifunctional mechanical crimping pliers allow you to strip cable insulation, trim wires and crimp.

Welding use

Self-welding of aluminum conductors is a rather more practical connection method than standard soldering. The option involves the use of a special powdered flux, diluted in water to a paste-like state, and a low-voltage welding machine.

Welding wires will require some skills on your part.

Welding technology:

• Remove the ends of the aluminum cables from the insulating layer over a length of 40–50 mm.
• Twist the exposed cores together.
• Apply a sufficient amount of paste-like flux to the twisted area using a brush.
• Apply an electrode to the ends of the flux-treated strand and weld the aluminum cores within a couple of seconds.
• Remove the electrode from the twist and visually verify the quality of the connection.

The flux applied to the twist prevents the flow of oxygen and the electrode from sticking to the surface of the molten metal. The result of correctly carried out manipulations is the formation of a neat aluminum “drop” at the end of the twist, which does not interfere with the free flow of current between the connected wires.

Security measures

Any contact connections, including aluminum conductors, are subject to a number of specific technical requirements to ensure safe operation. Such connections must be as resistant to mechanical stress as possible, durable and reliable.

You cannot use the option of twisting the contact surfaces - this will contribute to strong heating at the joints

In conditions of a small contact area, the contact area may suffer from significant resistance, therefore, using the simple overlap method or the option of lightly twisting the contact surfaces of aluminum conductors and other materials for connection is prohibited by standard safety measures. The galvanic couple formed in this case with oxides quickly provokes heating of the junction.

In accordance with the rules for electrical installations, all connections, branches and terminations of wire or cable conductors must be carried out by welding, soldering, pressing or squeezing in accordance with the currently valid instructions. The connection of aluminum wires in compliance with technology and the use of appropriate materials ensures a consistently low transient resistance contact.

Source: https://aqua-rmnt.com/ehlektrosnabzhenie/kak-soedinit-alyuminievyie-provoda.html

Why you can’t connect aluminum and copper wires, how to make the connection correctly - Site about

Almost everyone already knows that aluminum wiring is a legacy of the last century, and it must be changed when renovating an apartment. Few people carry out major repairs and forget about it.

However, there are situations when the repair is carried out partially, and there is an urgent need to connect an aluminum wire with a copper one or simply extend them by adding a few extra centimeters of wire.

However, aluminum and copper are not galvanically compatible. If you connect them directly, it will be something like a mini battery.

When current passes through such a connection, even with minimal humidity, an electrolytic chemical reaction occurs. Problems will definitely show themselves sooner or later.

Oxidation, weakening of the contact, its further heating with melting of the insulation. Transition to a short circuit or burnout of the core.

What such contact can ultimately lead to, look at the photo.

How to make such a connection competently and reliably to avoid problems in the future.

Here are some common methods that electricians use. True, not all of them are convenient for working in installation boxes.

Let's take a closer look at each of them and choose the most reliable one, which does not require subsequent maintenance or revisions.

Here a steel washer and bolt are used for connection. This is one of the most proven and simple methods. The truth is that it turns out to be a very large design.

For installation, twist the ends of the wires into rings. Next, select the washers.

They must be of such a diameter that the entire eye of the wire is hidden behind them and cannot contact another conductor.

The most important thing is how to position the ring. It must be put on so that when tightening the nut, the eye does not unfold, but rather is pulled inward.

Steel washers between conductors made of different materials prevent oxidation processes. In this case, do not forget about installing the engraver or spring washer.

Without it, contact will weaken over time.

The fact is that metals whose electrochemical potential of the connection does not exceed 0.6 mV can be safely connected to each other.

Here is a table of such potentials.

As you can see, copper and zinc have as much as 0.85 mV here! This connection is even worse than direct contact between aluminum and copper conductors (0.65 mV). This means the connection will not be reliable.

However, despite the simplicity of the threaded assembly, the end result is a large, awkward structure, shaped like a beehive.

And it’s not always possible to stuff this whole thing into a shallow socket. Moreover, even in such a simple design, many manage to screw it up.

The consequences will not keep you waiting in a very short time.

Another method is to use a nut-type connecting clamp.

It is often used to branch off a supply cable with a much larger cross-section than a tap.

Moreover, it does not even require cutting the main wire. It is enough to remove the top layer of insulation from it. Some have found a use for it to connect the input cable to the SIP.

However, you shouldn't do this. Why, read the article below.

But again, nuts are not suitable for junction boxes. Moreover, sometimes such clamps burn out. Here is a real review from a user on one of the forums:

There are a series of special clamps that can be used to join copper to aluminum.

Inside these terminals there is antioxidant paste.

However, disputes about the 100% reliability of such clamps, especially for sockets and not lighting groups, have not subsided to this day. When installed in a limited space, the contact may weaken, which will inevitably lead to burnout.

Moreover, this can happen even at a load below the minimum for which Vagos are designed. Why and when does this happen?

The fact is that when the connected conductors are compressed, a small gap appears between the pressure plate and the contact point. Hence all the heating problems.

Here is a very clear video that explains this problem without further ado.

This method has one significant disadvantage. Most of the pads sold are of very poor quality.

Some people get clever and, in order to avoid direct contact between copper and aluminum, the copper core is soldered to the side of such a clamp, rather than inserted inside.

True, the terminal will have to be disassembled for this. In addition, reliable aluminum contact under the screw without revision does not last very long.

The screws will need to be tightened every six months to a year. The frequency of revision work will directly depend on the load and its fluctuations during periods of maximum and minimum.

Forget to tighten up and expect trouble. And if this entire connection is hidden deep in the socket, then getting into it every time is not a very convenient task.

Therefore, the most reliable method available is crimping. Here we will not consider the use of specialized copper-aluminum sleeves GAM, since they start from sections of 16mm2.

For home wiring, as a rule, you need to increase the wires by 1.5-2.5 mm2 no more.

Let's consider the most common case that occurs in panel houses. Let's say you need to power one or more additional outlets from an existing aluminum outlet in a through niche.

For extensions, take a FLEXIBLE copper wire with a cross section of 2.5 mm2. This will reduce the mechanical impact on the aluminum core when you lay the wires in the socket box.

Strip the ends of the copper wire. Further, for such a connection they must be soldered. This will prevent direct contact between copper and aluminum in the sleeve. For soldering, it is convenient to use a homemade crucible, which is a slightly modified soldering iron in the shape of a hatchet.

• In this case, before soldering with flux, remove the oxide layer from the core.
• The tinning process itself involves dipping the wire into a special hole in the soldering iron filled with tin.
• After the core has cooled, the remaining flux is removed with a solvent.

Next, move on to the aluminum wires sticking out of the wall. Carefully clean their ends and also remove the oxide layer.

To do this, you can use oxide conductive paste. The same paste is used when installing modular pin grounding systems.

It is designed to work in any conditions and eliminates the further appearance of oxide on the surface of the wire. Keep in mind that the oxide film can subsequently have a resistance several times greater than the aluminum itself.

And without removing it, all your further work will go down the drain. Moreover, the melting point of such a film reaches 2000 degrees (versus approximately 600C for Al). After all the preparatory work, insert the wires into the GML sleeve from both sides. All that remains is to crimp this connection.

Some people will have a logical question: will the solder layer on the core be pressed through during crimping? Then it turns out that all tinning manipulations will be in vain.

The main thing here is to choose the correct cross-section of the sleeve and die of the tool for crimping.

In this case, the soft solder will, as it were, seal the contact spot of the copper-aluminum connection. And without oxygen access to this point, contact erosion will not be observed.

Be careful; when working with aluminum conductors, you must act with extreme caution, as this is a very brittle material. One careless movement and you are guaranteed to have a broken wire.

After crimping, it is necessary to insulate this connection with adhesive heat shrink.

It is the adhesive type that will ensure 100% tightness and prevent the flow of oxygen to the contact areas. In order not to risk burning the insulation, it is better to heat the heat shrink with a hair dryer rather than with a lighter or portable torch.

1. The resulting bundle of wires must be placed in the electrical box with great care, since aluminum does not like sharp bends.
2. Since the extended copper wires are flexible, you put insulated NShVI lugs on the ends of these conductors.
3. Only after this can they be safely inserted into the terminal blocks of the sockets and the screws tightened.
4. Of course, this is not the only way to extend aluminum wires, but it is one of the simplest (as opposed to welding or soldering) and reliable (as opposed to twisting). More details
5. If you have the slightest opportunity to change the entire aluminum wiring, be sure to do it, do not skimp on your safety.

Source: https://knaschool50.ru/garderob/pochemu-nelzya-soedinyat-alyuminievye-i-mednye-provoda-kak-sdelat-soedinenie-pravilno.html

How to properly connect aluminum wires to each other - Metalworker's Guide

When you need to connect 2 different sections of wire with each other, it is necessary, in addition to high-quality contact, to obtain sufficient strength of the section where these wires are connected to each other.

If we take into account the regulatory documents that are in force in our country, then it is permissible to connect aluminum wires to each other using various methods:

1. Welding.
2. Crimping.
3. Soldering.
4. Connection using terminals.

Despite the fact that all these connection methods specified in the regulatory documents are presented as universal, not all of them will be suitable when working with aluminum wires.

First of all, this is due to the characteristics of a material such as aluminum, in particular, its technical characteristics. As you know from a school chemistry course, there is always an oxide film on the surface of aluminum, formed as a result of direct contact with atmospheric oxygen.

It is not capable of conducting electric current through itself. In addition, the oxide film has a fairly high melting point - around 2000 degrees. This figure is significantly higher than the melting point of aluminum itself.

If you remove this film mechanically, it will appear again very quickly. It is worth noting that the presence of this film when soldering aluminum greatly interferes with the process of connecting the aluminum core to the solder. Also, it can cause difficulties when welding wires, because due to its presence various inclusions arise, due to which the quality of contact is greatly reduced.

Additional characteristics of a material such as aluminum include increased fragility and fluidity. In this regard, when connecting aluminum wires, care should be taken in advance to ensure that they are located so that the possibility of mechanical impact on this area is completely excluded.

It is worth noting that when connecting wires using a standard bolt clamp, it will have to be tightened periodically, since the metal will gradually flow out from under the bolt. As a result, the connection will become weaker.

Twist

Aluminum wires are often connected to each other using twisting. This is the simplest, but also the most dangerous method of connecting wires to each other.

The sequence of actions when using this technology will be as follows:

1. First , remove the insulation from the wires approximately 4-5 cm on each side. It is most convenient to use a special tool designed specifically for this purpose.
2. Now the contacts should be degreased. To do this, you will have to wipe them with a cloth pre-moistened in acetone.
3. Sandpaper is used to remove the oxide film from the surface of the metal, that is, to clean it until a metallic shine is obtained.
4. The wires are crossed with each other , after which one of the wires is wound as tightly as possible onto the other using pliers.
5. The second wire is wound onto the first in the same way.
6. The twist should now be insulated using insulating tape. Professional electricians also recommend using a special heat-shrinkable tube or cambric. With its help, you can qualitatively protect the exposed area from the negative effects of the external environment.

In principle, the technology is quite simple. You just need to remember that the wires need to be exposed at least 4-5 cm, and the twisting should not be done manually, but only with the help of pliers, so that the wires fit as closely as possible to each other.

If this is not done, the result will be loose contact, which can cause the area to become very hot. In turn, this effect causes a short circuit, and in some cases even a fire.

Threaded connection

This type of connection can be very reliable if done correctly. It is worth noting that aluminum has the greatest linear expansion, and therefore a gap appears between the connected wires over time, worsening their contact with each other. To prevent short circuits, you need to tighten these screws from time to time.

To get rid of this need, special washers with cuts or groovers are installed. They select the resulting gaps and increase the reliability of the connection several times.

The wires will need to be wound around the screw so that the area of ​​its contact with the contact pad is much larger. Professional electricians often do this: they flatten this ring on an anvil to increase the contact area.

The technology for making high-quality threaded connections of wires begins with removing the insulation from them to a distance equal to 4 screw diameters. The cleaned areas are degreased.

Then you need to bend their tips so that rings are formed.

The elements are put on the screw in the following sequence:

1. Spring washer.
2. Standard washer.
3. Ring of the first wire.
4. Another standard washer.
5. Ring of the second wire.
6. Screw.

This entire system is tightened until the spring washer is in a straightened state. In principle, if both wires are made of aluminum, then there is no need to place a standard washer between them.

We use terminal blocks

If aluminum wires have a low current load, they can be connected to each other using terminal blocks. Despite the fact that the appearance of such products may vary greatly, the principle of their operation is the same.

The body of the pads is made of plastic or carbolite. It contains tubes with thick walls made of brass. There are threaded holes on the sides. The wires to be connected are inserted into opposite ends and secured with screws. It should be noted that you can insert as many wires into one brass tube as will fit there.

This is not a very reliable connection compared to soldering, but installation work takes several times less time. In addition to connecting conductors made of the same material, it is permissible to use different wires in terminal blocks.

Permanent connection

If you do not plan to disassemble the wire connection in the future, you can use the so-called one-piece methods. These methods are among the most reliable. It is advisable to use them, first of all, in hard-to-reach places.

One of the easiest methods of permanent connections is crimping. To do this, take an aluminum tube of suitable diameter, twist the wires together, insert them into this tube and clamp them with press pliers. It is best here that the conductors fit as tightly as possible.

Only in this case will the connection be the most durable. It is worth noting: if the wires fit into the tube quite tightly, then you don’t even have to twist them together. At the last stage, the connection is isolated.

Today on sale you can find special tips for making this connection, which already have an insulating cap. It shrinks together with the tip and wraps around the wires, blocking any access to them.

To obtain a high-quality permanent connection, you need to have special pliers that will not bite, but only squeeze. If they are not available, then standard pliers will do just fine.

Soldering and welding

Soldering wires allows you to get a fairly high-quality and permanent connection. However, when connecting aluminum wires, you should be aware of the presence of an oxide film on them, due to which the solder will not adhere very well.

To prevent such a defect from occurring, you need to follow a certain sequence of actions:

1. The connected sections of wires are treated with a special flux, which removes the oxide film from the surface.
2. The solder is processed as carefully as possible so that it has the largest area of ​​contact with the wires.
3. When the connection area has cooled , it is advisable to treat it with sandpaper to remove sharp edges that could damage the insulating layer.
4. Wires must be insulated.

Soldering requires certain skills.

It should be said that this method has several negative aspects:

1. He has to be isolated.
2. The method itself is quite complicated , especially if you have to solder wires under the ceiling while standing on a stepladder.
3. If an error was made during the work , then correcting it will be quite problematic.
4. A lot of time is spent on work.

Welding is somewhat reminiscent of soldering wires, but it is much faster. In order to obtain a high-quality connection, the electrode is brought to the connection area for only 1-2 seconds. Both ends of the wire are pre-treated with flux to remove the oxide film.

If you have no experience in this area, then you should initially practice on twists prepared in advance, but not connected to the system.

After completing the welding process, the twists are treated with a special solvent and varnished. The result is a high-quality connection that can last for a long period of time, since this method helps prevent overheating. Accordingly, such an area will need to be isolated.

  How to distinguish zinc from aluminum

Alternative options

flat spring clamp

The wires can be connected to each other using a rivet. In principle, this technology is similar to screw technology, only here a rivet is used instead of a screw. The end result is a permanent connection.

This connection is made quite simply: both conductors are put on the rivet through a spring washer, then it is inserted into the rivet gun and the handles are pulled together until a click is heard.

There is also a special flat spring clamp. Such products are disposable and reusable, when the wire can be either inserted or removed. However, it should be remembered that such clamps are made of plastic, so it is not advisable to use them for currents exceeding 10 A.

Working with them is very simple: the wires are stripped and inserted into the clamp until they click. It is impossible to pull them out from there without using a special lever. It is also advisable to insulate this section of the wire.

Connection Features

Aluminum wires are best placed in special junction boxes, to which they should be approached in corrugated sleeves. This is especially important when the installation is carried out outdoors or in the case of wiring in a damp room such as a bathroom.

In general, when connecting aluminum wires that will function outdoors, care must be taken to ensure that moisture does not approach the connection areas.

https://www.youtube.com/watch?v=ZH1ZLOYL_xo

Otherwise, short circuit will not be avoided. In this case, it is very convenient to use the technology of welding wires, since the subsequent use of a special varnish eliminates the impact of water on the joint, and the insulating layer will additionally protect against electric shock.

Blitz tips

1. Professional electricians do not recommend connecting aluminum and copper wires together. This is due to many reasons, the most important of which is the different resistance of metals. In addition, when interacting with each other, copper and aluminum oxidize very quickly, which causes heating of the wires and significantly worsens the contact. In addition, their rigidity is different, which significantly complicates the work.
2. You can, if necessary, combine certain methods of connecting wires. In particular, twisting goes well with soldering or welding. The result is a very reliable and permanent contact that will last for a long time.

Source: https://ssk2121.com/kak-pravilno-soedinit-alyuminievye-provoda-mezhdu-soboy/