How to twist aluminum and copper wire

How to properly connect copper and aluminum wire

Connecting wires made of dissimilar metals (a particular and most common case is copper and aluminum) is most often necessary in cases where the home wiring is made of copper conductor, and the entry into the house is made of aluminum.

It happens the other way around. The main thing here is the contact of dissimilar metals. Copper and aluminum cannot be combined directly.

The reasons lie in the electrochemical properties of metals. Most metals, when combined with each other in the presence of an electrolyte (water is a universal electrolyte), form something like a regular battery. For different metals, the potential difference upon contact is different.

For copper and aluminum this difference is 0.65 mV. It is established by the standard that the maximum permissible difference should be no more than 0.6 mV.

If there is a higher potential, the conductor material begins to deteriorate and become covered with oxide films. The contact will soon lose reliability.

For example, the electrochemical potential difference of some other pairs of metals is:

• copper - lead-tin solder 25 mV;
• aluminum - lead-tin solder 40 mV;
• copper – steel 40 mV;
• aluminum – steel 20 mV;
• copper – zinc 85 mV;

Twisting wires

The simplest, but least reliable way to connect conductors. As mentioned above, you cannot directly twist copper and aluminum wires. The only possible contact option for such materials is tinning one of the conductors with lead-tin solder.

It is very difficult to tin the aluminum at home, but there will be no problems with copper. A powerful soldering iron, a piece of solder and a little rosin or other flux for soldering copper and copper alloys is enough. Tinned copper and pure aluminum conductors are tightly twisted together using pliers or pliers so that the wires wrap tightly and evenly around each other.

It is unacceptable for one conductor to be straight and the other to wrap around it. The number of turns must be at least 3-5. The thicker the conductors, the fewer the number of turns you can make. For reliability, the twisted area can be wrapped with a bandage made of thinner tinned copper wire and additionally soldered. The twisting area must be carefully insulated.

Threaded connection

The most reliable connection of wires is threaded (bolted). The conductors are pressed against each other using a bolt and nut. To make such a connection, it is necessary to make rings at the ends of the connected wires with an internal diameter equal to the diameter of the bolt.

Just like for twisting, the copper core must be tinned. Multicore wire must be serviced (even if wires of the same metal are connected).

The resulting compound looks like a sandwich:

• bolt head;
• washer (with an outer diameter no less than the diameter of the ring on the wire);
• one of the connected wires;
• second wire;
• washer similar to the first one;
• screw;

A significant disadvantage of this method is its large dimensions and, as a consequence, difficulties with insulation.

Terminal blocks

The most technologically advanced way to connect wires is to use special terminal blocks.

Terminal blocks have a number of advantages over other connection methods:

1. Ease of installation.
2. Use of any combinations of conductor materials.
3. Connecting conductors of different diameters.
4. There is no need to manipulate the wire other than stripping its end of insulation.
5. There is no need to insulate.
6. Convenience of securing the block itself.

Clamping of the conductor in the terminal blocks can be done in 2 ways - directly with a screw, or using a metal clamping plate. The second option is preferable, since in the first case there is a risk of damaging the wire with the screw (aluminum is a very soft metal).

Permanent connection

This installation method is performed in the same way as using a bolt and nut, but using a special tool - a riveter. The operating principle of the riveter lies in the rivet design.

It is a hollow aluminum tube with a thickening at one end. A metal rod with a head is inserted into the rivet. When the rod is pulled through the rivet, it forms a bulge at the other end of the rivet, while simultaneously expanding the tube itself somewhat.

When a certain maximum force is reached, the rod breaks off, leaving a clean, formed rivet. If you do not take into account the cost of the tool, the price of an individual rivet makes this type of installation the cheapest after twisting. There is only one drawback - such a connection is disposable and permanent.

Another option for permanent connections is obtained by using special tinned copper connecting tubes. Such tubes are produced in several diameters to suit the most common diameters of the wires being connected.

The stripped ends of the wires are inserted into the opposite ends of the tube and the latter is crimped with a special device. Together with twisting, this is the most compact type of connection of conductors.

Alternative options

The method of connecting dissimilar wires using special spring clamps has recently become quite widely used. The most famous clamps are from Wago.

There are 2 types of such clamps:

1. Disposable , without the ability to pull out the wire.
2. Lever , reusable.

The principle of operation is a special spring clamp made of a special alloy, which is enclosed in a plastic case. The design of the clamping edge allows it to cut into the metal body even if there is a thick oxide film on it.

Clamps are produced for almost all used conductor diameters and are designed for currents up to 34 A. However, experience in electromechanical work suggests that the maximum permissible current must be reduced several times, that is, clamps must be purchased with some current reserve.

Wiring using spring clamps is the fastest. One of the disadvantages is the fairly high cost of materials.

Features of the use of connections for external and internal work

All of the listed methods for connecting conductors of dissimilar metals are intended for the internal electrical network. For outdoor work, it is better to use a special plastic clamp “Nut”.

The plastic body of the clamp contains several metal plates. The clamp body is tightened with special screws and reliably protects the connection point from contact with the environment. As a rule, external electrical networks are not as critical of connection dimensions as they are indoors, so connections with the “Nut” clamp are a pretty good option.

Blitz tips

And finally, a few tips that you should take into account in order to protect yourself in the future and not redo the work:

1. To strip conductors, you should not use side cutters, pliers or any other tool with a similar operating principle. In order to cut the insulation without affecting the body of the wire, considerable experience is required and still in most cases the integrity of the wire will be compromised. Aluminum is a soft metal, but it does not tolerate bending very well, especially if the integrity of the surface is damaged. It is possible that the wire may break during installation. And it’s much worse if this happens a little later. It is necessary to remove the insulation with a sharp knife, moving it along the conductor, like stripping a pencil. Even if the tip of a knife removes some layer of metal, a scratch along the wire is not terrible.
2. To tin copper conductors, under no circumstances should you use acid-containing fluxes (zinc chloride, etched hydrochloric acid, etc.). Even thorough cleaning of the connection will not save it from destruction for some time.
3. Stranded conductors must be tinned before installation to obtain a monolithic conductor. The only exceptions are spring clamps and terminal blocks with clamping plates.
4. Washers, nuts and bolts for detachable or permanent connections should not be made of galvanized metal. The potential difference between copper and zinc is 0.85 mV, which is significantly greater than the difference when copper and aluminum are directly connected.
5. For the same reason, you should not purchase overly cheap terminal blocks from an unknown manufacturer. Practice shows that the metal elements in such pads are often zinc coated.
6. You cannot use the advice to protect the direct connection of copper and aluminum conductors with various water-repellent coatings (grease, paraffin). Machine oil is difficult to remove from leather alone. The sun, air, and negative temperatures will destroy the protective coating much faster than we would like. In addition, some lubricants (especially grease oil) initially contain up to 3% water.

Source: https://vi-pole.ru/kak-pravilno-soedinit-mednyj-i-aljuminievyj-provod.html

How to connect aluminum wires

Almost every electrician will say and agree that electrics is the science of contacts. In practice this becomes obvious. A large number of problems in the power supply arise due to heavy wiring overload, as well as weak contacts in the junction box. In this article, we will focus on the last problem, namely how to connect aluminum wires.

What is their feature?

Aluminum has special metal properties that can make joining difficult. Due to oxidation, an oxide film forms on aluminum, which prevents the passage of electric current. This film will melt only at a temperature of at least 2000°C, and this figure is higher than the melting point of aluminum itself. Moreover, if you clean off the oxide film mechanically, then after a while it appears again.

If you want to solder aluminum, this film will prevent the solder from adhering to the core. Also, during welding, the film forms inclusions that negatively affect the quality of contact.

Among other things, aluminum belongs to the category of metals that are characterized by high fluidity and brittleness. As a result, the contact should be completely protected from possible mechanical influences.

For example, if you connect aluminum with a bolt clamp, then you need to regularly tighten the contact, since the aluminum, figuratively speaking, “leaks out” from under the contact, which, in turn, weakens.

Are there then ways to reliably connect aluminum wire? Let's look at a few common methods and decide how best to get the job done.

Screw

This connection method is very simple. It is necessary to strip the wire of 20 mm of insulation. Afterwards it is recommended to clean the vein with fine-grained sandpaper. Next, twist the bare core into a ring and insert it into the clamping screw, which should be tightened tightly.

Complete set for screw connection

The disadvantage of this connection method is that due to the fluidity of aluminum, the contact must be tightened from time to time. Therefore, the connection point must be in an accessible location.

Spring

In this case, special terminal blocks are used. Due to the presence of a special spring, there is no need to regularly tighten the contact. The inserted stripped aluminum wire is held securely. There are terminal blocks, both disposable and reusable.

Disposable ones are used to connect wires without further disconnection. The wire is inserted into the hole in the clamp; it cannot be pulled back out. As for the reusable connection, the wire is easily pulled out if you press the special lever that holds the wire.

Twist

In rare cases, aluminum wire can be connected by twisting. It is immediately worth noting that this method is very unreliable, even despite the fact that in Soviet times it was used relatively often. This is partly explained by the fact that in the past the number of household appliances and, accordingly, the load on the wiring was less. Now the picture looks different.

Moreover, the life of such a connection depends on various factors, such as current load, humidity and temperature. If the temperature rises, the metal expands, causing the gap between the wires to widen. This can lead to transient resistance, the contact area will heat up and then oxidation will form and, in the end, the contact will be completely broken. However, this process continues for a long time, so the twisting method is acceptable for temporary connections.

When joining aluminum using this method, it is important to adhere to the following rules:

• The wires should wrap around each other evenly.
• If the wire is thick, then there should be no more than three turns, and for a thin wire, no less than five.
• If copper and aluminum wires are connected, then the copper wire must be tinned.
• It is recommended to use heat-shrinkable tubing as contact insulation.

Welding

Fast and reliable connection method. This technology is especially relevant if a large number of connections need to be made. However, for this you need to have a welding transformer and skills.

Wire welding

The welding process is as follows:

• The wires are twisted together.
• Apply a special flux to the end.
• Afterwards, welding occurs with a carbon electrode for up to 2 seconds.
• As a result, a drop should form at the end of the twist.

Flux

• The drop should be treated with a solvent and then varnished.
• When the varnish has dried, the connection is isolated.

Soldering

The method of soldering the connection is simple. This will require components such as rosin, a soldering iron, solders and additional elements. So, the wire is twisted, and then apply solder to them with a soldering iron.

Crimping

For such a connection, you will need special press pliers and sleeves, which are hollow rods. To crimp, strip the ends of the wires, insert them into the sleeve and perform crimping in three places. You can also additionally twist the wires.

Crimping kit

If the wire is aluminum, then use an aluminum sleeve; for copper wires, use a copper sleeve. If you are connecting aluminum to copper, then copper-aluminum sleeves are available for sale.

Aluminum and copper wire

Connecting 2 copper and aluminum wires may cause some problems. The problem lies in the potential difference, the difference of which reaches up to 0.65 mV. When humidity increases due to this difference, the contact will be destroyed. Moreover, the contact will heat up, which can lead to disastrous consequences.

Therefore, we recommend connecting these two wires so that there is no direct contact between them, namely:

• one-piece;
• threaded;
• terminal;
• with spring contact.

Using these techniques, aluminum wires can be connected to copper wires.

In this article, we looked at several methods on how to connect wires to each other. If you know of other methods, please leave a comment at the end of this article.

In the video provided, you can learn about other intricacies of connecting aluminum wire:

Source: https://kakpravilnosdelat.ru/kak-soedinit-alyuminievye-provoda/

Methods for soldering aluminum wires

Despite the fact that in modern construction, during electrical work, aluminum cables are increasingly being replaced by copper cables, aluminum remains an indispensable material in the manufacture of large-section wires and cables.

The reasons for this lie on the surface - the electrical resistivity of aluminum is approximately one and a half times greater than that of copper, and the volumetric weight is three times less.

With a large conductor cross-section, when weight is more important than strength, the choice in favor of aluminum is obvious. The cross-sectional area of ​​an aluminum conductor will be one and a half times greater than that of a copper conductor, and at the same time, aluminum will still be two times lighter than copper. Soldering, among other methods, is used to connect wires.

Soldering methods

The problem with using aluminum conductors is their rapid oxidation. The oxide film significantly impedes the passage of electric current during connections. To do this, twisted aluminum wires are soldered.

You can solder aluminum wires in a junction box using a soldering iron or a gas torch. It is more difficult to use a soldering iron due to the inability to accurately heat to the required temperature. And for aluminum, overheating is just as unacceptable as underheating.

Metal has high thermal conductivity, and the insulation over a large area from the soldering point can simply melt.

It is easier to regulate the heating temperature with a gas burner, but it takes a long time to prepare the surface. However, it is the torch that will need to be used if it is necessary to solder any massive parts to each other. In any case, when soldering aluminum wires, they need to be prepared.

Preliminary processing

The difficulty with soldering is that aluminum itself is a very low-melting material (660 ℃) and if heated carelessly it can melt.

Another factor that makes soldering aluminum wires difficult is rapid oxidation in air.

The oxide film on the surface of the material reliably protects aluminum from the effects of all kinds of external factors, but it also prevents the adhesion of solder to the material and must be removed.

It is almost impossible to mechanically remove the oxide film under normal conditions. The material is instantly oxidized and covered with a new film. You can mechanically remove the oxide film under the oil layer.

But before this, the oil must be heated to 200 ℃ in order to remove any active oxygen that may be present there. This method is very inconvenient at home and labor-intensive.

Therefore, the ends of aluminum conductors must be tinned before soldering. Using rosin or most other fluxes will not work due to the high chemical resistance of the oxide film. It does not dissolve even with organic acids.

To tin the wires, you must use both a special flux and a mechanical method.

Of course, this must be done before the wires are twisted, otherwise it will not be possible to mechanically clean the entire surface of the wire. Only the tinned ends can be twisted together and soldered.

Working with a soldering iron

In order to solder aluminum with a soldering iron, there are several methods, the essence of which is to clean immediately under the flux layer in direct contact with the molten solder.

The first method is that aluminum conductors, before soldering, are cleaned with a hot tinned soldering iron using a mixture of rosin and steel filings.

Sawdust has an abrasive effect, rosin removes all impurities and immediately the cleaned areas are covered with solder, which should be on the soldering iron tip.

The second method involves stripping the aluminum wire on medium-grit sandpaper directly under the influence of a hot soldering iron with solder and flux.

Gas burner

Processing with a gas burner is carried out when the parts are in the position relative to each other in which they will be used. The processing smoothly transitions into the soldering process itself.

This happens as follows:

• the burner heats the surfaces of aluminum parts;
• upon reaching the temperature at which the metal is reduced from the oxide, the film is mechanically peeled off;
• under the influence of a flame, the parts are coated with flux, and solder is introduced into the soldering area.

If the parts are thick, then their edges must be cut at an angle of 45°. Typically, heating occurs to the melting point of tin, when the solder spreads and fills the twist groove.

Differences in technology when using flux

Thanks to the achievements of modern science and technology, flux compositions for aluminum have been obtained that actively dissolve the oxide film and protect the material from further oxidation.

Examples of such drugs are formulations labeled F-59A and F-61A. The letter A means that these compounds are intended for soldering aluminum.

When using these fluxes, soldering aluminum wires is greatly facilitated. It is enough to simply treat the finished twist with flux, without even heating it, and then, after heating it with a soldering iron or torch, apply solder.

It will spread over the entire surface of the wires and adhere well, providing a strong and electrically conductive solder joint.

Features of soldering stranded wires

Stranded wires must be soldered only using a special flux, since their mechanical processing is almost impossible. Soldering technology differs in that each wire must first be well treated with flux.

To do this, the bundle will have to be untwisted and fluffed. After processing, each thin wire conductor is covered with solder and the bundle is twisted. After this, twist the two ends and solder it.

Can it be connected to copper?

Situations often arise when it is necessary to connect an aluminum wire to a copper wire. This is perhaps the only case where soldering cannot be used.

It's all about the aluminum itself. It cannot be soldered to other metals at all due to its physical and chemical properties. When connecting directly to copper, galvanic corrosion will occur between the two active metals and will quickly destroy the connection.

And if they are soldered using solder that is neutral to both materials, then the different coefficients of thermal expansion of the metals will quickly destroy the soldered contact. After all, when current passes through a conductor, it will certainly heat up, and after switching off, it will cool down.

Safety precautions

Safety precautions when soldering aluminum wires boil down to observing general precautions when working with electric heating devices, open flames and aggressive liquids, such as fluxes.

It is unacceptable to use faulty soldering irons with damaged insulation and with more power than necessary.

Do not use burners near flammable objects. When working indoors, forced ventilation must be properly organized.

Difficulties in soldering aluminum wires

The main difficulty when soldering aluminum wires, as indicated above, is the presence of an oxide film on the surface of the metal. Fighting it greatly slows down the soldering process.

And if you consider that aluminum wires are now used mainly for laying external power wiring, it becomes obvious that a regular soldering iron and sandpaper will not be enough in this case. Welding is increasingly being used to connect such wires.

Source: https://svaring.com/soldering/praktika/pajka-aljuminievyh-provodov

How to connect copper and aluminum wire

I continue to talk about wires, today there is an interesting article that will be devoted to connecting copper and aluminum cables. It seems that this is complicated, everything can be twisted, but not everything is so simple. After all, these materials simply oxidize when they come into contact with each other, and the load on the wiring increases. It is necessary to take into account the so-called electrochemical compatibility

CONTENTS OF THE ARTICLE

Why might such a question arise, namely the connection of aluminum and copper. It's simple, before (during the USSR) aluminum wiring was installed in almost all apartments, because it was much cheaper. Now 90% of all installations are made of copper. And if you bought an “old stock” apartment for an apartment, then when you change the wires you will have to connect them.

Electrochemical compatibility

This is basic chemistry. Different materials have different electrochemical compatibility (a simple example is a battery). What happens if you connect aluminum and copper wires ? If the contact point is in a vacuum, airless space in which there is no moisture, then such a connection can last a very long time.

However, as you know, air has such a concept as “relative humidity”; it is water that causes the destruction of this compound. Water penetrates between the contacts, creating a galvanic element, current begins to flow in this circuit and with this impact one of the electrodes, in our case the wires, is destroyed.

For a long time there has been such a thing as electrochemical potential, knowing which you can determine which wires can be connected and which cannot!

So what do the standards tell us? It is possible to connect materials with an electrochemical potential (simply voltage) between them that does not exceed 0.6 mV. However, between aluminum and copper this figure is 0.65 - 0.7 mV, it should be noted that it is very high. But for example, with ordinary stainless steel it is only 0.1 mV.

It follows from this that it is simply impossible to directly connect these two elements; the point of contact will collapse very quickly, and the more humidity you have, the faster the destruction will occur.

However, we have such a problem, we need to combine two incompatible wiring. It turns out that everything has already been invented a long time ago.

Twist

The simplest wiring connection. However, in our case it is not recommended. But there is a way out. To remove the excessive potential difference, you need to coat the copper wire with tin-lead solder, and after that you can easily twist it. I strictly do not recommend twisting wires without solder.

The disadvantage of this method is that you still need to find such solder, and you need to hold the soldering iron “correctly” in your hands. YES, and we live in the 21st century, there are still many faster and more correct methods.

Threaded connection

The second "easiest" method. Take a steel bolt with a nut and several washers. Then the ends of the wires are cleaned and two rings are made from them according to the diameter of the bolt. After that, one end is put on (for example, aluminum), then washers are laid (preferably spring) and after that the second end (copper) is put on, after which the nut is tightened.

Thus, we insulate the wires from each other, and steel is a universal “adapter”.

Connecting "nuts"

The principle is the same as that of a bolt. Only here the wires are connected through metal plates, which have 4 bolts for tightening. The ends are wound on one side and the other, and then pulled together, the main thing is that they do not touch each other. Lastly, everything is closed with a plastic case on springs, similar to a “nut”, hence the name.

Terminal block

Probably the most common way. Now there are just a lot of such pads, for any size and power. There is a plastic case that has a steel insert with two bolts at the ends. As you probably understand, we run the wires on different sides and tighten the bolts along the edges, the main thing is that they do not touch.

Using WAGO

Here guys need to be divided into two types:

Not collapsible

Usually this is a cast body, sometimes transparent. Inside it there is a metal strip and two springs; you insert the ends of the wires each in its own direction, and the springs prevent them from coming back out. The connection is strong, but not removable - no, of course you can rip the wires back, but the connecting capabilities of this terminal will no longer be at a high level. The cost of such terminal blocks is very low, about 5 - 9 rubles per piece.

Collapsible

As it became clear, this is almost the same clamp, but with a slight difference, it has two levers for fixing the spring. If the levers are lowered, the wires are “sitting” tightly and it is difficult to pull them out, but if you lift them up, the end of the wire comes out easily. This clamp can be used many times. However, its price is twice as high, about 15 - 20 rubles apiece.

Not standard methods

You know, there is another method, but most likely it will not suit you. We are talking about “rivets”; they are now widely used for fastening various metal roofing and house cladding. However, for this method you will need a special tool - a “rivet gun”.

The principle is simple - insert a rivet into the tool, tighten it and cut off what is not needed. The most important thing is that these rivets have a steel core, and therefore our copper and aluminum materials will not come into contact with each other.

Just like with a bolt, you need to use metal washers to insulate the wires. The cost of such a connection is very low because the rivets really cost pennies. However, the result is a non-removable section; when dismantling it, you simply need to cut it off.

Also be sure to take care of the connection insulation.

These are the main methods for connecting copper and aluminum cables. Personally, I use WAGO terminal blocks and clamps, which is very convenient and I recommend it to you. Now watch a short video on the topic, the three best connections in my opinion.

I will end here, I hope my article was useful to you, read our construction website.

Source: http://remo-blog.ru/e-lektrika/kak-soedinit-medny-ji-alyuminievy-j-provod.html

Is it possible to twist copper wire with aluminum

Let's start with the fact that is it possible to connect aluminum wires with copper wires, and will such a connection not lead to a fire? The answer is yes, you can. But let's first get acquainted with these materials.

If you ask yourself which wiring is better, copper or aluminum, then the choice is, of course, copper.

This comes out of the technical characteristics of copper; the cross-section of aluminum wire under the same conditions has to be taken larger. There are also disadvantages: copper is more expensive.

It is easier to distinguish copper wire from aluminum by color; copper has a reddish tint, aluminum is gray and white.

Having looked at the electrical performance of metals, the question of which conducts current better disappears. Here's some information:

• Resistivity: copper – 0.017 Ohm mm²/m, aluminum – 0.028 Ohm mm²/m.
• Heat capacity: copper - 0.385 J/gK, aluminum - 0.9 J/gK.
• Elasticity of the material: copper – 0.8%, aluminum – 0.6%.

So why can’t you twist copper and aluminum wires, because twisting, especially with a small cross-section, is the cheapest option in terms of both money and time? The thing is that these materials, when connected, create a galvanic couple.

Galvanic pair - 2 metals of different kinds, the connection of which will lead to increased corrosion. Copper and aluminum are just such a galvanic pair.

The electrochemical potentials of the two metals are too different, so rapid corrosion will increase the resistance at the junction and subsequent heating. More details about the compatibility of metals are indicated in GOST 9.005-72.

Below is a table with some data on metals:

Galvanic compatibility of meltals

You can achieve high-quality contact between two conductors in different ways (soldering, using a simple terminal block, more expensive WAGO terminals, or an ordinary bolt and nut).

Connecting wires

Connecting aluminum and copper wires to each other requires technological solutions; simple twisting is not enough.

Methods for connecting conductors with different electrochemical potentials:

• By soldering. But not simple soldering.
• Using simple terminal blocks or expensive WAGO. There is no point in saving money here, and if the question is how to properly connect copper and aluminum wires, then it is better to take WAGO. The advantages of this manufacturer will be described below.
• Using a bolted connection, which has many advantages: low cost, simplicity and the ability to work with large cross-section wires.
• Crimping with sleeves. Requires specialized tools.

WAGO

WAGO clamps for joining aluminum and copper are very popular, as they are very convenient to use:

1. Click the pressure plates to the side.
2. Insert wires into holes.
3. Place the plates in their places and clamp them.

WAGO terminals for connecting copper wire to aluminum are an excellent solution

But now WAGO is casting doubt on its reputation. According to numerous reviews, the spring contact weakens, which leads to burning of the terminal block and its rapid replacement.

Terminal blocks

The list of electrician tools and consumables includes terminal blocks.

Terminal blocks are copper or brass coated with a layer of nickel, designed for wires of a certain cross-section and covered with a layer of insulating plastic.

The wires are secured with 2 small screws.

When connecting copper and aluminum terminal blocks, the locking screws must be properly tightened.

If you tighten them, you can damage the aluminum conductors, which will not have a very good effect on the further operation of the electrical wiring.

Therefore, it is necessary to find a middle ground: not tighten too tightly, but achieve high-quality contact.

Bolted connection

If you don’t have a terminal block, soldering iron or WAGO at hand, and the cross-section of the wires is large enough, then you can achieve high quality with an ordinary bolt.

To connect two wires you will need: a bolt, a nut, 3 washers. Sequencing:

1. Make rings at the ends of the wires, the same diameter as the bolt. For convenience, it is better to use round nose pliers.
2. Place the rings on the bolt in such an order that they are between the three washers.
3. Tighten the nut and check the quality of the connection.
4. Apply several layers of insulating tape.

Bolted connection of aluminum and copper

Nut connection

"Nut" is another type of terminal block, most often used for branching large-gauge wires. It consists of 2 copper plates placed in a plastic case.

Copper and aluminum wire, as well as a branch wire, are placed between the plates. But you can simply use the “nut” as a connecting element.

After laying the conductors, the plates are tightened with bolts.

As insulation, a plastic case is placed over the entire structure, consisting of two halves, for fastening which standard screws are used.

Walnut connection is suitable for all types of street connections and branches

Lubrication

To improve the quality of contact, you can use a special lubricant or paste. Usually this is quartz vaseline paste. It is usually used to improve the connection of aluminum wires.

But this paste can be used for all types of connections (threaded, using terminal blocks, crimping), especially if the connection takes place outdoors.

Then the contact is affected by additional factors that significantly reduce the durability of the connection. Although the use of lubricant without insulation raises doubts.

Bottom line

Based on all of the above, select the method that is suitable for you, depending on the location of the connection (street, house) and material capabilities.

Source: https://steelfactoryrus.com/kak-pravilno-soedinit-mednyy-i-alyuminievyy-provod/

How best to connect copper and aluminum wire - electrician's advice - Electro Genius

In most new buildings, electrical wiring is initially made of copper wires. This is dictated by the increased load on the network caused by a large number of electrical appliances. In addition, copper is more durable, does not oxidize and has better electrical conductivity.

But in old houses, aluminum wiring is installed everywhere. Many people, planning a major renovation, replace aluminum wires with copper. However, not everyone has such an opportunity. In addition, sometimes replacement is not possible due to technical reasons.

What you should know

In these cases, it is necessary to connect aluminum and copper conductors to each other. But such a connection by simple twisting is prohibited: electrochemical corrosion begins between the wires, caused by natural humidity, and such contact is quickly destroyed. It is best to connect wires of the same material.

But the connection of copper and aluminum conductors is quite common. To do this, you can use various methods that have proven themselves in practice. The most commonly used options for making such a connection are presented below.

Methods for reliably connecting different wires

There are several ways to connect aluminum and copper in electrical wiring. The main objective of all these methods is to ensure the reliability and durability of the contact, while minimizing the possibility of electrochemical corrosion.

Screw connection

The screw method of connecting aluminum and copper conductors is simple, yet reliable and durable. This option can be used if it is necessary to connect wires of different or large cross-sections. The essence and technology of this method is as follows:

• The ends of both wires are cleared of insulation (approximately 30 mm);
• Using pliers, the ends are bent into a circle.

Then a bolt of suitable size and diameter is taken. The structure is assembled in the following order:

1. A regular washer is put on the bolt;
2. Circumference of the first conductor;
3. Again the puck;
4. Second wire ring;
5. Another puck;
6. The structure is clamped with a nut;

One of the advantages of this method is the ability to connect more than two wires. The maximum number of clamped cores is limited only by the length of the bolt.

WAGO clamps and terminal blocks

A more modern version of the block is equipped with a clamp from the German manufacturer WAGO. These terminals are available in two types:

1. One-piece pads have a cast, often transparent body. To fix the wires, just insert the cleaned ends of the wires into such a cap, the clamp will securely fix them. The disadvantage of this method is that it is disposable: to redo the connections, you will need to bite off the old clamps;
2. Detachable terminal blocks do not have this drawback. A special lever makes it easy to fix the wires, and if necessary, disassemble the connection; just lift it up, the clamps will open and the ends will come out of the terminal.

Using such clamps, you can make a multi-core connection (from 2 to 2), and also use the terminal block as an adapter for a branch in electrical wiring. Another advantage of this method for connecting copper and aluminum is that there is no need for additional insulation of the contacts. The body of the WAGO blocks is completely insulated and reliable.

Permanent connections

Finally, let's look at another way to connect copper to aluminum wires. To do this you will need a special rivet tool. Now such devices are widely popular, and many craftsmen already have them.

The technology of this method is similar to the method using a bolt and nut. Let's look at how, using a rivet tool, you can make a reliable connection of electrical wires:

• Having stripped the conductors of insulation, the ends are folded into a small ring using round pliers. It is important that the diameter is as small as possible so that the rivet does not dangle too loosely;
• Then the structure is assembled in the same order as with the screw method: copper and aluminum conductors are put on the stud, a small washer is used as a gasket;
• After this, the rivet rod is placed in the head of the device, the handles of which are compressed until it clicks. The connection is ready!

The disadvantage of this method is the inability to disassemble the structure. If you need to connect another wire, the rivet will have to be cut out and the connection made again. Also, we should not forget about the importance of insulating this area: you can use cambrics or insulating tape.

Let's sum it up

We have studied the most common and used methods of connecting current-carrying conductors from various materials: copper and aluminum. They are reliable, provide long-lasting contact and eliminate oxidation which leads to electrochemical corrosion.

Source: https://orenburgelectro.ru/baza-znanij/kak-luchshe-soedinit-mednyj-i-alyuminievyj-provod-sovety-elektrika.html

How to connect aluminum wire to copper

February 25, 2017

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Wiring in old houses most often does not meet the requirements that have developed in our time. The use of many household appliances and increased loads require the replacement of entire sections or the entire distribution system in an apartment or house. At the same time, take into account the basic rules of how to connect an aluminum wire with a copper conductor in order to prevent emergency situations.

After all, the situation when you need to make an insert from copper wire into existing aluminum wiring occurs very often. This is not recommended, but if you are faced with a similar problem, everything must be done to avoid a fire due to a short circuit.

Reasons why this method of connection is prohibited

A clear example showing the danger of such a procedure is the principle of operation of a galvanic cell, described in the school curriculum.

Twisting two wires of different metals is similar to the appearance of current in a conventional battery, due to the process of interaction of two different materials in the electrolyte.
In dry air conditions, the likelihood of such a phenomenon is almost zero.

Therefore, for some time, even in conditions using powerful devices, the connection point will last for a certain time. But the consequences will still be very unpleasant.

Gradual destruction leads to the fact that the resistance parameters of materials will steadily increase.
Significant heating of the connection zone occurs when high-power consumers are connected. With frequent use, the risk of fire increases many times over. Therefore, long-term joining of conductors made of different materials is not recommended by experts. If there is an emergency, you will need to learn a few tips.

Advice from professional electricians

It is not always possible to use scientific methods scrupulously, but in any situation, do not forget that the most effective is the use of terminal blocks. A simple and safe technique is available for quickly completing the procedure even by an electrician with little experience. Three types of such connections are most often used.

Method "Nuts"

The specific shape of the elements for the time-tested version gave it this name.
The main component of the design is three plates designed to fix wires between them. The second wire is inserted without the need to cut the central line. All that is required is to strip the insulating layer at the joint for subsequent clamping between the “nuts”. The outlet wire is placed between the plates and twisted.

WAGO

Such Vago devices have excellent characteristics in terms of reliability and simplicity. The docking process takes literally a few seconds. Everything happens in an accessible form - the ends of the current-carrying wires are stripped and inserted into the connectors intended for this purpose.

Galvanic reaction and oxidation are prevented thanks to a special lubricant filling the internal space. But in the case of powerful devices, this technique is not very effective. The optimal area of ​​use is connecting lighting fixtures.

Pads

The connection process using blocks is similar to that discussed above, but for consumers with high power they are much more reliable. Sufficient plate thickness can withstand significant loads. It should be remembered that it is better not to do installation in conditions of high humidity. The absence of insulating lubricant can cause the appearance of a galvanic couple.

Bolt fastener

The joining of aluminum and copper is also allowed in this way. For a correctly carried out clamping procedure, a washer made of anodized steel is placed between dissimilar metals. Strength testing is carried out at least twice within 12 months. More frequent maintenance is required in networks with high loads.

Soldering iron

This method requires compliance with certain conditions.

Copper can be soldered very easily, but problems arise with aluminum. Chemically resistant amalgam prevents solder and stumps novice electricians.

This layer can be removed this way: after cleaning the soldering area, apply a few drops of copper sulfate to it. Then a copper wire is connected to the positive pole of the Krona battery, and an aluminum conductor is connected to the negative pole. Soon a deposit of copper layer will form on it, suitable for soldering.

Note! All considered methods provide for rigid fixation of stripped conductors. But when twisting wires from different metals, for some reason they forget about this requirement.

A characteristic feature of aluminum is plasticity under high loads, which is also called fluidity. Only regular maintenance and tightening of the clamping elements will protect you from the terminal catching fire due to excessive overheating.

Some tips

• Do not clamp stranded copper wires;
• choose a terminal with a channel corresponding to the wire cross-section;
• the increased fragility of brass sleeves and terminals is the reason why you should avoid pinching;
• Pay attention to the marking with the indicated current strength.

Sleeve connections

It is best to use such a device to connect an aluminum outlet with a stranded copper wire. A “pigtail”, freed from insulation, consisting of twisted veins, is inserted into the hollow tip. After crimping with pliers, the tip is inserted into the terminal.

Twist

When twisting a stranded conductor, be sure to cover the “pigtail” with solder to ensure good contact.
It is recommended to cover the ends with insulating caps. In conditions of high humidity, such a connection is not recommended. Destruction of the docking site quickly.

Source: http://jelektro.ru/covety-elektrika/%D1%81%D0%BE%D0%B5%D0%B4%D0%B8%D0%BD%D0%B8%D1%82%D1%8C -%D0%B0%D0%BB%D1%8E%D0%BC%D0%B8%D0%BD%D0%B8%D0%B5%D0%B2%D1%8B%D0%B9-%D0%BF %D1%80%D0%BE%D0%B2%D0%BE%D0%B4-%D0%BC%D0%B5%D0%B4%D0%BD%D1%8B%D0%BC.html

How to connect aluminum wires: do it quickly and correctly

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.

The use of pliers and other auxiliary tools may affect the quality of the connection, so their use is unacceptable. However, when comparing price and quality, the crimping method is one of the best for connecting aluminum wires.

Source: https://Elektrik-a.su/energii/soedineniya/kak-soedinit-alyuminievye-provoda-260

How to connect aluminum wires to copper wires correctly?

Depending on the type of connection you choose, you will need different materials and tools.

For mechanical connections:

• pliers;
• knife or device for removing insulation;
• PPE caps;
• terminal blocks;
• self-clamping terminals;
• sleeves;
• screw terminals;

When crimping, you will need presses (hydraulic, mechanical, manual of various types, press pliers, etc.).

For welding you will need the following:

• argon-arc welding machine;
• oscillator;
• rubber boots;
• welding mask;
• burner;

For soldering;

• knife or device for removing insulation;
• soldering iron (for small sections of aluminum wires – 60-100 W; for sections larger than 2 mm – 100-200 W);
• solder (POS40, POS60 solders are ideal for home use);
• steel brush;
• sandpaper;

The choice of fluxes deserves special attention, since the better the flux, the easier it will be to solder aluminum. Today, despite the large selection of fluxes, the most preferred ones for soldering aluminum at home are FIM, F-64, FTBf.

Connection methods

The need to connect aluminum products with copper, aluminum or aluminium-copper especially often arises in Soviet-built apartments - this occurs due to the failure of individual sections of aluminum electrical wiring, or due to its complete replacement.

Few people know that the joints must be as strong as possible to prevent heating. If the work done is done poorly, the resistance will increase, causing them to heat up, which will result in a short circuit.

The following methods exist:

1. Soldering.
2. Welding.
3. Mechanical connections:
   • twist;
   • use of terminal blocks;
   • use of contact clamps (self-clamping terminals);
   • connection using bolts;
   • crimping method (crimping);
   • spring devices;

Each of the listed methods has characteristic features.

Spike

The safest method is soldering - with certain skills you can perform soldering at home:

1. Before soldering, the ends of the wires must be tinned: the part that will be connected is thickly coated with rosin and placed on a grinding surface (wheel or sandpaper).
2. Next, the wire is pressed to the surface with a soldering iron, constantly adding rosin until the required thickness of the wire is achieved.
3. After which the soldering is carried out in the usual way.
4. The most important thing in the soldering process is to prevent the aluminum surface from coming into contact with oxygen - otherwise, a heat-resistant oxide film will form. To do this, the cable to be stripped is generously lubricated, or filled with flux, and in some cases, heated.
5. In the case of soldering wires with a cross-section of up to 4 mm2 , they can be cleaned directly in the solution.
6. If the cross-section of the aluminum wire is 4-10 mm2, it is necessary to remove the insulation, clean it to a shine and twist it.
7. When soft solders are used , AF-44 flux is optimal.
8. The resulting connection should be cleaned of flux residue, wiped with gasoline, coated with moisture-resistant varnish, then with electrical tape, then with varnish again.

Crimping (crimping method using sleeves)

For cases when it is necessary to connect a multi-core cable, or more than 2 single-core wires into one connector, it is best to use crimp sleeves:

1. into such a sleeve .
2. After which the sleeve is compressed using a press or special pliers, a reliable, permanent contact.

This method is most widespread when connecting powerful consumers.

Instead of sleeves, NKI tips are widely used, at one end of which there is a small crimp sleeve - cable cores are inserted into it. At the other end there is a slip ring, thanks to which you can get a high-quality connection with screw terminal blocks.

Using Terminal Terminals

The easiest way to combine aluminum cables into a single current-carrying core is to use contact clamps.

Their types:

• polyethylene clips;
• self-clamping terminals (terminal blocks);
• screw;
• spring (PPE caps);

Advantages of contact clamps:

1. They do not require additional insulation ; to connect, it is enough to strip the aluminum cables, assemble them into a bundle, and then screw the clamp onto the bundle until it stops (insert it into the terminal, or clamp it with a screw, etc.);
2. The resulting contacts have much greater mechanical strength than when twisted;
3. The resulting contacts do not heat up, which minimizes the possibility of short circuits and fires.

Spring connection (PPE caps)

These are caps made of non-flammable plastic, with metal springs located inside. After screwing the PPE onto the wires (twisting), the springs move apart, compressing the cable cores and ensuring tight and reliable contact, and also removes the layer of oxides from the wires.

At the same time, plastic serves as electrical insulating, fire and mechanical protection for the entire connection. For high-quality contact, the size of the PPE caps must be selected correctly - they must be screwed onto the cables with force.

Adviсe

1. When using a bolted connection, it is necessary to remember about the fluidity of aluminum - the clamping bolt must be periodically tightened so that the aluminum does not leak out over time. At the same time, the mechanical pressure on the cable without tension should not exceed 150 kg/cm2. When the tip is clad with copper, the pressure should not exceed 100kg/cm2. When heating live wires, the maximum pressure is no more than 200 kg/cm2.

   If these values ​​are exceeded, the aluminum cable will “leak” under voltage.

2. If you have no other choiceIn addition to using simple twisting, you must remember that the contact will be more reliable when using certified PPE caps. Remember that any cable contacts covered only with electrical tape are not recommended.

3. For quick and high-quality soldering of aluminum cables, it is necessary to replace rosin with high-quality mineral oil (for sewing machines) or gun oil.
4. When choosing self-clamping terminals , we recommend reading the markings, which display the number and cross-sectional area of ​​the cable for which the device is designed.
5. Any mechanical connection of an aluminum wire with a copper wire is possible only when the latter is coated with tin-lead solder.

Source: https://slarkenergy.ru/provodka/cable/kak-soedinit-alyuminievye.html