Is it possible to connect an aluminum wire with a copper one. How to connect aluminum to copper wire

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

Aluminum has special metal properties that can be difficult to bond. 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 the oxide film is cleaned mechanically, then after a while it reappears.

If you want to solder aluminum, this film will prevent the solder from adhering to the strand. Also, during welding, the film forms inclusions that negatively affect the quality of the contact. Among other things, aluminum belongs to the category of metals that are highly fluid and brittle. As a result, contact should be completely protected from possible mechanical stress... For example, if you connect aluminum with a bolt clamp, then it is necessary to regularly tighten the contact, since aluminum, figuratively speaking, “flows out” from under the contact, which, in turn, weakens.

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

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

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

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. Inserted stripped aluminum wire is held securely. There are both disposable and reusable terminal blocks. Disposable are used to connect wires without further disconnection. The wire is inserted into the hole of the clamp, you cannot pull it back. As for the reusable connection, the wire is easily pulled out if you press the special lever holding the wire.

In rare cases, the aluminum wire can be twisted together. It should be noted right away that this method is very unreliable, and even though Soviet time it was used relatively often. This is partly due to 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 duration of such a connection depends on various factors, for example, current load, humidity and temperature. If the temperature rises, then the metal expands, which causes the gap between the wires to expand. This can lead to transient resistance, the contact point will heat up and then oxidation is formed and, in the end, the contact will be completely broken. However, this process takes a long time, so the twisting method is acceptable for temporary connections.

When connecting aluminum in this way, 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 one, at least five.
• If copper and aluminum wire are connected, then copper must be tinned.
• It is recommended to use heat shrink tubing as contact insulation.

Each of these methods has a place. Several factors influence the choice:

• Availability of suitable tools and equipment.
• Wire diameter.
• Availability of consumables.
• Availability of relevant skills.

Let's consider each permanent connection method separately.

Fast and reliable connection method. Moreover, this technology is relevant if you need to make a large number of connections. However, this requires a welding transformer and skills.

The welding process is as follows:

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

• The drop should be treated with a solvent, and then varnished.
• When the varnish is dry, the joint is sealed.

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

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

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

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

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

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

In this article, we looked at several methods of how to connect wires together. If you know about other methods, then leave comments at the end of this article.

Video

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

Aluminum wiring is now rarely used for wiring electrical networks in houses and apartments. It must be replaced during repair work. However, it also happens that the work is carried out partially. In this case, a problem arises: how to connect copper and aluminum wires.

What problems can arise when connecting aluminum and copper

Answering the question whether it is possible to connect copper with aluminum, it should be recalled that when twisting copper and aluminum wires, the following problems arise:

1. Decreased electrical conductivity. Aluminum is an active metal; under normal conditions, it is covered with an oxide film that has low conductive qualities. Copper is devoid of this property.
2. Looseness of contacts. Plaque build-up makes the contacts worse. Such a film does not form on copper conductors; therefore, metals are considered electrochemically incompatible.
3. Fire hazard. Asking the question of how to connect an aluminum wire with a copper one, they remember that electrical contact occurs between the oxide deposits formed on the wires. Over time, metals begin to heat up, resulting in a fire.
4. Electrolysis. If the system is operated in high humidity conditions, the connection begins to deteriorate, becoming a source of fire. Corrosion primarily affects the aluminum parts of the wiring. With regular heating and cooling, cracks appear in the insulating braid, the joint becomes covered with an oxide or salt layer, which accelerates destruction.
5. Conductive soot formation. In this case, contact is broken, a fire starts in the house. When using electrical wiring in a dry room, this process takes years. At high humidity, fire occurs after a few months.

Ways to connect different wires

How to connect copper and aluminum wires:

• using a different metal;
• preventing the formation of harmful oxide deposits.

In the second case, special compounds are used that can protect the metal from the effects of moisture and oxidation. The pastes prevent the breakdown of the joint. Tinning is another method of protection against fire. Tinned multi-core cable can be twisted with single-core aluminum. For connection, special devices are also used:

1. Clamps. Used to connect to the aluminum riser in the driveway. Branch clamps are punctured or lacking. The device is equipped with an intermediate plate that excludes contact of two metals. Some clamps are treated with paste. Sometimes the use of special formulations is not required.
2. Spring-loaded and self-clamping terminal blocks. Connecting and splicing wires made of different metals can be done using terminals with sockets and partition plates that separate aluminum from copper conductors.
3. Bolts. When making a bolted connection, a washer made of stainless or galvanized steel is placed between the wires.

Terminal blocks

Terminal blocks are:

1. Disposable. They are used when connecting wires in junction boxes and installing chandeliers. Efforts must be made to insert the conductors into the opening of the device. Removing the cable from the connector is even more difficult.
2. Reusable. There is a lever for fixing, thanks to which the cable can be inserted and removed several times. Blocks of this type are used when connecting stranded wires from different metals. If the work is done incorrectly, the connection can be redone.

Installation is carried out as follows:

• the cable is cleaned of the insulating coating;
• veins are stripped to a metallic sheen;
• a lever rises on the reusable terminal block;
• the cleaned part of the wire is inserted into the hole of the block until it stops;
• the lever returns to its original position.

Crimping

In this case, tubular sleeves are used, reliably and safely fastening the wiring elements. To connect the cables, you will need a press, mechanical, hydraulic or electrical pliers. Installation includes:

• sleeve selection and tool adjustment;
• cleaning the wires from the braid;
• stripping the veins (sandpaper is used for this);
• applying quartz-vaseline composition;
• inserting the ends of the cables into the rivet;
• crimping (when using a simple tool, several crimps are performed at a short distance; when using a good tool, the crimp is performed once);
• insulation of joints.

The wires are inserted into the sleeve from opposite sides so that the joint is in the middle of the connector. The conductors can be inserted from one side. The connection of cables with a sleeve is sometimes replaced by the use of “nut” clamps, but the latter are less reliable. Over time, the rivet loosens, increasing the risk of fire.

Bolted connection

Subject to the installation rules, the method provides a durable fastening. To complete the work, you will need 2 simple washers, 1 spring washer, a nut and a bolt. The wires are cleaned of insulating material. A spring washer is placed over a bolt that is inserted into a plain washer. The end of the aluminum cable is rolled up with a ring, which is thrown over the bolt. After that, put on a simple washer and tighten the nut. A stranded wire is covered with solder before starting work.

Soldering

This is a reliable and technologically advanced method that ensures a high-quality connection. Before soldering, the conductors are cleaned of the braid and oxide film. If necessary, the cables are tinned, twisted loosely, treated with flux and sealed. Do not connect aluminum and copper wires using acid flux. The composition destroys metals, reducing the strength of the fastening. The junction is insulated in the usual way.

Features of the connection lived on the street

When performing work on the street, take into account that the wires will be affected by precipitation, high and low temperatures, and wind. Therefore, when performing installation work, sealed structures are used that are insensitive to ultraviolet radiation and high humidity. Piercing clamps are used when connecting wires on roofs, facades and poles.

What's in electrical engineering copper and aluminum conductors cannot be directly connected, is not a secret even for many ordinary people who have nothing to do with electrics. From the side of the same inhabitants, the question often sounds to the professional electricians: “Why?”.

Why little people of any age can drive anyone into a dead end. Here is a similar case. Typical answer of a professional: “Why-why ... Because it will burn. Especially if the current is large. " But that doesn't always help. Since this is often followed by another question: “Why will it burn? Why does not copper with steel burn, aluminum with steel does not burn, and aluminum with copper does not burn? "

There are different answers to the last question. Here are some of them:

1) Aluminum and copper have different thermal expansion coefficients. When a current passes through them, they expand in different ways; when the current stops, they cool down in different ways. As a result, a series of expansion-contractions changes the geometry of the conductors, and the contact becomes loose. And then, already in the place, heating occurs, it worsens even more, an electric arc appears, which completes the whole thing.

2) Aluminum forms an oxide non-conductive film on its surface, which worsens the contact from the very beginning, and then the process proceeds in the same way: heating, further deterioration of contact, arc and destruction.

3) Aluminum and copper form a "galvanic pair", which simply cannot but overheat at the point of contact. And again heating, arc and so on.

Where is the truth, after all? What happens there, at the junction of copper and aluminum?

The first of the given answers is still untenable. Here are tabular data on the linear coefficient of thermal expansion for metals used for electrical installation: copper - 16.6 * 10-6m / (m * g. Celsius); aluminum - 22.2 * 10-6m / (m * g. Celsius); steel - 10.8 * 10-6m / (m * g. Celsius).

Obviously, if it was a matter of expansion coefficients, then the most unreliable contact would be between a steel and aluminum conductor, because their expansion coefficients differ by two times.

But even without tabular data, it is clear that differences in linear thermal expansion are relatively easily compensated for by using reliable clamps that create a constant pressure on the contact. Expansion of metals, compressed, for example, with the help of a well-tightened bolted connection, remains only to the side, and temperature drops are not able to seriously weaken the contact.

The option with an oxide film is also not entirely correct. After all, this same oxide film allows you to connect aluminum conductors to steel and to other aluminum conductors. Yes, of course, the use of a special lubricant against oxides is recommended, yes, a systematic revision of compounds with the participation of aluminum is recommended. But all this is allowed and works for years.

But the version with a galvanic pair really has a right to exist. But here all the same it does not do without oxides. After all, a copper conductor is also quickly covered with oxide with the only difference that copper oxide more or less conducts current.

During electrolysis, ions carry charges and move by themselves. But, in addition, ions are particles of conductor metals. When they move, the metal is destroyed, shells and voids are formed. This is especially true for aluminum. Well, where there are voids and sinks, it is no longer possible to have a reliable electrical contact. Bad contact starts to get warm, it gets worse, and so on until it burns out.

Note that the more humid the surrounding air, the more intensively all the above processes take place. And uneven thermal expansion and a non-conductive layer of aluminum oxide are only aggravating factors, nothing more.

In addition to the article, there is a useful plate, which clearly shows the compatibility and incompatibility of individual metals and alloys when they are combined. Copper and aluminum cannot be connected to each other, since they are incompatible.

Note: C - compatible, H - incompatible, P - compatible when soldering, when directly connected they form a galvanic pair.

There are still quite a few apartments in which the electrical wiring is made with aluminum wires. And since manufacturers of lighting devices and electrical engineering have switched to copper power cables, the question of how to connect copper and aluminum wires is still relevant today. Due to the fact that copper and aluminum have different electrical potentials, then a voltage will necessarily form between them. If this bond of two metals were located in a vacuum, then the bond would last forever. The same cannot be said about an airy atmosphere where humidity is present. She is the catalyst chemical processes inside the contact of copper and aluminum.

Experts have long come to the conclusion that a potential difference of more than 0.6 mV is already dangerous for wire connections. Such contact cannot be called long-term. As for copper and aluminum, the electric potential between them is 0.65 mV, which is higher than normal. It turns out a galvanic pair, like in a battery. Therefore, it is not allowed to connect them in electrical wiring. But what about those who have an aluminum wiring diagram in an apartment or house? There are several ways out.

Twisting two wires

The oldest way to connect electrical wires is twisting. It is also the simplest one. We return to the electric potentials of metals. For aluminum with lead-tin solder, the potential difference is 0.4 mV, for copper with solder it is only 0.25 mV. It turns out that if one of the wires to be connected is treated with this solder, then they can be safely connected. Typically, the solder is applied to the copper wire.

You can tin both single-core wire and stranded wire. In the second case, the cores must be twisted, taking into account their number. For cables with a large cross-section, three conductors can be tinned, for small cross-sections (no more than 1 mm²), five conductors.

But even this connection option does not give a 100% guarantee that the contact will work for a long time. There is such a thing as the linear expansion of metals, that is, under the influence of temperatures, they expand. When twisting, it is not always possible to achieve a tight clamping of the wires to each other. When expanding, gaps are formed between them, which reduce the density of the abutment. And this leads to a decrease in the conductive value. This is why twisting is rarely used today.

Threaded contact

It is believed that threaded connections of copper with aluminum are the most reliable contacts that will serve without problems the entire service life of the wires themselves. The ease of connection and the ability to connect several cables in one node make this type in demand today. True, it is usually used for joining large cross-section wires. The number of connected electrical lines will be limited only by the length of the bolt (screw).

We return to the electric potential of metals and determine that between aluminum and steel (all the elements of the bolted connection are made of it), the potential difference is 0.2 mV, between copper and steel - 0.45 mV, which is again less than the standard. That is, oxidation does not threaten all metals present in the bond. The strength of the connection of aluminum wires with copper in this case is ensured by a well-conducted nut clamp. Steel washers are installed between the two cores as a contact limiter or breaker.

Attention! During the operation of the threaded connection, care must be taken to ensure that the nut does not spontaneously loosen under the influence of vibrations of the building. This will weaken the contact. Therefore, a Grover washer must be placed under the flat washer.

How to make the correct contact with a threaded connection

To properly connect aluminum and copper wires to each other, you must:

• Remove the insulating layer to a length equal to four bolt diameters. If an M6 bolt is used, then the length open area should be 24 mm.
• If the veins already have oxidation on the surface, then they must be cleaned.
• The ends are rolled up into rings with a diameter slightly larger than the diameter of the bolt.
• Now, in sequence, they are put on the bolt: a simple flat washer, any one wire, a flat washer, the second wire, another flat washer, Grover's washer and a nut, which is tightened all the way.

Please note that for clamping in this way wires with a cross section of no more than 2 mm², an M4 bolt can be used. If the copper wire is soldered, it is not necessary to place a washer between the two conductors. The end of a stranded copper cable must be soldered.

One-piece connection

This type of contact is similar to the previous one, only it is one-piece. And if it becomes necessary to add another wire to it, then you will have to break the connection and make it in a new way. Basically, this contact is based on a riveting clamp. The process itself is carried out using a special tool called a riveter.

• The ends are cleaned of insulation, as in the previous version.
• Rings are made slightly larger than the rivet diameter (its maximum value is 4 mm).
• The aluminum end is put on first.
• Then a flat washer.
• Copper end.
• Another washer.
• Insert the end of the rivet into the riveter and squeeze the handles of the tool until it clicks, which indicates that the steel rod has been cut.

Contact in the terminal block

This type of connection between copper and aluminum wires is most often used in lighting fixtures. The pads are supplied with the fixtures. In terms of connection reliability, they are inferior to threaded contacts, but this is one of the simplest options. There is no need to twist rings, or to tin the ends, to carry out insulation. It is necessary to strip the wires to a length of 5-10 mm and insert them into the terminal grooves of the device. The clamp is made with a screw. Effort will have to be applied, especially for the aluminum wire.

If copper and aluminum are interconnected using a terminal block, then the device cannot be laid under plaster. It can only be used in closed boxes: in a junction box or in a luminaire cover.

Terminal block

Wago

There is no way to bypass the Wago adapter. This is a German-made device with which you can connect aluminum and copper together without effort and without tools. The only thing to do is clean the ends of the wires.

The Wago terminal block is a spring-loaded device into which the cable cores are inserted, and it automatically clamps them. Today the manufacturer offers two types of pads: disposable (773 series) and reusable (222 series). In the first case, the wires are inserted into the terminal block and you can only pull them out from there by breaking the device. The second option is a device that includes levers. By raising or lowering them, you can pinch the end of the core or release it. Each plug-in socket has its own lever.

In a disposable terminal block, you can install wires with a cross section of no more than 2.5 mm² (it can withstand a current of up to 10 A), in a reusable terminal block no more than 4 mm² (current up to 34 A).

Nuts

Another structure with which you can dock aluminum to copper. The device consists of a metal plate-type connecting element and a plastic case, somewhat similar to a nut. Hence the name.

The fastening principle is the same as for the threaded version. Only by design, these are two plates that are pressed against each other by four screws. In one of the plates, a thread is cut in the holes, onto which the screws are screwed, squeezing the plates together. Connect aluminum with copper walnut as follows:

• Protects the ends of the conductors.
• One is inserted from one side into a specially formed groove between the plates.
• On the other hand, a second is inserted. It is important here that the two wires (aluminum and copper) do not touch inside the connector. Therefore, the walnut contains an additional steel plate, which is located between the clamping elements. So one wire must be placed on top of this plate, the second under it. This will ensure that there is no contact between copper and aluminum wires.
• The screws are tightened all the way to ensure reliable contact.
• The construction is closed by a spring-loaded casing.

Manufacturers today offer a wide variety of nuts, both in strength and in size. There are options in which the case itself does not open, and the entire filling is hidden in it and is inaccessible. The connection is made by inserting the end of the wire into the socket, where it is clamped with a screw. There are nuts with a serrated connection, you just need to insert the conductor into the groove, where compression with the teeth will take place, which will ensure reliable contact.

Returning to the questions whether it is possible to connect, and how to connect copper and aluminum wires correctly, it is necessary to generalize that there are many options. Each has its own pros and cons, but underneath necessary requirements you can choose one correct one, which will create conditions for long-term operation electrical circuit wiring.

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When repairing (even if only cosmetic), we are often faced with the need to put in order the electrical wiring. In old houses, it happens that the wires are almost the same age as the owners of the apartment, and therefore it is simply necessary to replace entire sections of the wiring.

But this is the main problem: very often old wires are made of aluminum, and you only have a piece to replace.We immediately make a reservation that, according to all the rules, it is strictly forbidden to join them, but there are all sorts of situations.

So in this article we will discuss aluminum and copper ones, so as not to become the culprit of a short circuit and a fire?

Why can't you do this?

In order for you to fully understand the danger of such actions, you should talk about why copper and aluminum wires should not be twisted. We have to remember physics and chemistry.

You remember what it is Roughly speaking, you can call it a battery, the current in which arises as a result of the interaction between two metals in the electrolyte. Accordingly, the twist between aluminum and copper is such a battery.

Of course, in dry air, the formation of galvanic currents, which quickly destroy the material, is practically impossible. Yes, even a twist to an outlet, which is constantly used to connect a kettle or other powerful appliance, will not fall apart in a couple of hours, but trouble awaits you for sure.

Judge for yourself: over time, the materials of the wires are gradually destroyed, the resistance is constantly increasing. Accordingly, the place of twisting begins to heat up very much when a powerful consumer of current is connected to the outlet. If this happens regularly, then the likelihood of a fire becomes extremely high.

That is why it is not recommended to dock aluminum and copper wires for a long time. How to connect them if there is an urgent need? Agree, at the dacha there is not always an opportunity to visit an electrical goods store!

Once again, we repeat that it is far from always possible to do everything "according to science", but we still strongly advise you to use terminal blocks to connect the wires. This is the easiest, fastest and safest way even the most inexperienced electrician can connect wires. Consider the most common design types.

"Nuts"

The oldest and most proven method are called nuts. As you can understand, they got the nickname because of their specific form. Structurally, they consist of three plates, between which the wires are fixed.

A special advantage of this method is the fact that it is not at all necessary to cut the central line to insert the second wire. To do this, you just need to clean in the right place insulation, and then clamp this area between the two "nut" plates. A branch wire is inserted between them, after which the plates are securely twisted together.

WAGO

No less common are the methods of connecting wires, which are combined under one abbreviation WAGO. These are very simple and reliable devices with which you can dock everything in a couple of seconds. This is done as simply as possible: the ends of the wires are stripped of insulation, after which they are inserted into the connectors.

The trick here is that the inner space of this connection is filled with a special lubricant, with the help of which oxidation and galvanic reaction between different kinds metals. But! We could recommend the use of this kind of device only in those networks to which powerful devices will not be connected.

The fact is that under a strong load, connections of this type will be very hot, as a result of which the terminal materials will begin to collapse. It is not surprising that WAGO is most often used when working with lighting fixtures.

Terminal blocks

They are also quite common and popular. They look most like a small strip with terminals. As in the case described above, to use them, you must strip one end of the wire, then insert it into the adapter hole and tighten the bolts. On the other hand, everything is done exactly the same.

Here, again, there is a catch. How will aluminum and copper wires behave in this case? How to connect them if you need to connect really powerful devices to the network?

Fortunately, pads are fine for this purpose. If the thickness of the insulating plate is normal, then it can withstand even very high loads without problems. But remember that it is highly not recommended to mount in a room with high humidity. They do not contain any insulating grease, so the formation of a galvanic pair is not excluded.

What other ways of connecting wires are there? Let's figure it out.

Bolt-on fasteners

This mounting method is also great when you need to mate copper and aluminum. The wires are clamped with a bolt, and a washer made of high-quality anodized steel must be placed between the two metals. Remember that this type of connection must be checked for strength at least twice a year. If such a joint is used in a network that has high loads, then this should be done even more often!

Soldering iron

Is it possible to solder wires that are made of different metals? Yes, this is possible, but there are some important conditions to be met.

We will not talk about copper for a long time, since there should not be any difficulties in this matter. But there will be problems with aluminum. They are caused by amalgam, which instantly forms on the surface of this metal when it enters the oxygen environment. She is surprisingly persistent in chemically, and therefore the solder does not stick to it in principle. This is constantly faced by those novice electricians for whom any soldering of aluminum wires is a curiosity.

How do you remove this annoying film? First you will have to prepare a saturated solution. copper sulfate, battery "Krona" and a piece of normal copper wire(not Chinese). On the aluminum wire, it is necessary to carefully clean the place of future soldering, and then drop a couple of drops of copper sulfate solution on it.

Attach aluminum to the negative pole of the battery, and a piece of copper wire to the positive pole. Dip its end in. After a while, a fairly decent layer of copper will settle on the aluminum, on which you can easily solder the wire you need.

As you can see, soldering wires, even in this case, is able to provide a reliable and high-quality connection.

Important!

In almost all cases that we have considered above, rigid fixation of wires stripped from insulation is used. Somewhere for this, terminals are used, somewhere bolts ... But few take into account one important point, twisting aluminum and copper wires. We already know how to connect them, but the safety precautions of this process are also worth talking about.

The fact is that under load, aluminum becomes quite plastic and begins to "flow". All (!) Connections of this kind must be checked regularly and the bolts must be tightened. Otherwise, the day will come when the terminal holding on to parole will simply flare up, unable to withstand strong heating.

• Stranded copper wires should never be clamped. The fact is that when clamping, a whole range of conditions is formed that this wire does not like very much. So, part of the veins may well crawl out of the compound. The rest of the wire will be under a very high load, which may well result in a fire.
• It is very important to choose the terminal exactly for the cross-section of the wire you are using. From a too narrow or wide channel, the wire will simply fall out, and this is fraught with unpleasant consequences.
• Do not pinch! In most cases, brass is used in terminals and sleeves, and this material is highly fragile.
• Look carefully at the markings that indicate the maximum permissible amperage. As a rule, it is exaggerated: it is better to divide the indicated value by two.

We strongly advise against buying the so-called NoName from China. You will not go broke by spending a couple of rubles more, but buy a really high-quality terminal from a normal manufacturer! The manufacturers "Tridonik", "ABB", "Verit" have shown themselves to be excellent.

But what about the stranded option?

If you read the article carefully, then you already know perfectly well that stranded wires should not be clamped. But what about the case when you need to connect them to a thick aluminum bend, but you don't have a soldering iron, copper sulphate and a battery, and you don't want to bother with them?

It's time to tell you that there are special types of wire connections that are just designed to solve this kind of problem.

Sleeve connections

In specialized shops for electricians, you can easily find sleeves that are specially designed for normal connection. They look like miniature tournament spears of knights: behind a protective plastic cap is a hollow metal tip.

How to work with them? It's simple: carefully remove the insulation from the end of the wire, twist the veins into one "pigtail", and then insert it into the hollow tip. After it is crimped (you can use the most common pliers). The resulting tip is pushed into the terminal.

This makes it easy to connect wires without soldering. Of course, the aforementioned "pigtail", provided that a soldering iron is available, no one forbids irradiating with solder and welding with aluminum in the way that we described above.

Twisting

Of course, doing twists among professional electricians is considered bad manners and almost a violation professional ethics, but anything happens in life, and therefore no one is immune from the need to make such a connection.

What advice can you give in this case? To begin with, twisting the aluminum and copper wires is allowed only after thorough stripping of the aluminum section. If the copper wire is presented in a multi-core version, it must be not only twisted into one "pigtail", but also covered with solder for better contact.

Twisting should be done as carefully as possible, avoiding breaking the wires. It is recommended to close its ends with a special insulating cap, which can be purchased at almost every hardware store.

Finally, we have already repeatedly written that the twist should in no case be in a room with high humidity. In such conditions, the connection is destroyed almost instantly.

In a word, although it is not recommended by professional electricians to connect copper and aluminum wires, using the simplest means you can easily complete it without exposing your house to the danger of fire.