How to connect aluminum and copper wire? Ways to connect aluminum and copper wires, how to connect wires correctly, expert advice How can you connect aluminum wire to copper

27.06.2020

Very often in old houses it is necessary to repair electrical wiring connect aluminum wires of old wiring with copper- newly laid.

Those who are unfamiliar with this topic and make repairs with their own hands simply stupidly twist them together and close them in the junction box, not understanding what kind of headache they will get themselves in the future ...

This topic - copper with aluminum - is encountered not only when installing internal electrical wiring, but also when replacing the entrance to the house

The fact is that the wires of the overhead line (VL) are aluminum and if you do input cable copper, then it’s impossible to just wind a cable core onto an aluminum wire!

But they do! How many times have I seen it myself ... And then they are surprised - “Why is the light in my house blinking ?!”

Yes indeed, why? But because of what.

A little chemistry. Aluminum is a very active metal, try soldering it simple method like copper wire, nothing will work.

Aluminum actively reacts to air, or rather not even to the air itself, but to moisture in the air, quickly forming a thin film of oxide on its surface.

This film provides high resistance to electric current - the so-called “transitional resistance” appears at the junction of the wires.

But the copper wire also oxidizes, but not as strongly and intensively as aluminum and the oxide film on the copper surface has much less resistance to the flow of current.

It turns out that when connecting copper and aluminum wires, they contact with their oxide films.

Also, these two metals have different linear expansion, therefore, when the temperature in the room changes or the magnitude of the current flowing through the copper-aluminum twist, the contact between them over time weakens.

Transitional resistance in the twist so "slowed down" electricity, and even the weakening of the contact further increased the value of the transient resistance.

This causes the twist to start bask, the further, the more, the insulation of the wire is heated. is destroyed by heat and can even tan.

You yourself know how many houses burned down due to faults in the electrical wiring, and it is often the contact resistance or poor contact that is to blame for this.

Speaking of transient resistance.

This is active resistance , that is, all the power on it is 100% converted into heat, well, as in an iron, for example)))

To understand what it is, imagine that two wires are interconnected nichrome wire and an electric current flows through them, which heats the nichrome red hot.

Here, inside the twist of copper and aluminum wire, there is such a red-hot nichrome thread. Do you need it?

Remember, the transition resistance is an analogue of a hot nichrome filament.

Yes, chemistry is enough. Now how to get out of the situation if necessary connect copper wire to aluminum.

The point is this: the main thing is that these two metals did not touch between themselves. Between them there must be a material that is neutral with respect to them, naturally conductive.

It can be lead solder, duralumin, steel, stainless steel, chromium coating.

By the way, interestingly, it’s impossible: zinc, carbon (graphite) and silver with gold and platinum.

Although I can’t imagine who can afford such a pleasure - to combine copper with aluminum through platinum)))

In this case, if there is a sea of \u200b\u200bmoney, it’s better to make wires completely out of platinum, voltage losses will disappear completely)))

So, we connect copper with aluminum:

- With terminal clamps;

- Bolted connection through washers

- Layer of neutral material

Terminal clamps are branch clamps (the so-called “nuts”), wago, terminal blocks in isolation, etc.

Well, the bolted connection is so clear - a loop is made on the wire, a bolt is inserted, and between copper and aluminum - steel washers.

Such a connection is much more reliable than all terminal blocks and clamps, the only negative is the large dimensions, they take up a lot of space in the junction box.

I did this myself, for example, at the input to the house - when it was necessary to connect a copper cable with an aluminum input from the overhead line. Moreover, the cable was four-core, and the network was 220.

Then he made two cable cores per phase and zero, connected them through a bolted connection with a piece of aluminum wire, and this piece was already connected by power engineers to the input.

Already the second year has passed - there are no comments))) This is in the presence of an electric stove in the house and everything else - electric titanium, kettle, iron, microwave, etc.

Now about the layer of neutral material. I mean lead-tin solder.

How this is done I will show in the photo:

This is a good way out when there are no clamps on hand or do not want to use them, and the bolted connection does not fit in the box.

Then you need to cover the copper wire with solder and make a twist with aluminum - the connection will be reliable! Although the PUE is wrong ...

It requires either soldering-welding or terminal blocks-bolts, pure twisting according to the PUE is illegal ...

Although I personally once opened the lighting distribution box in an old house, there was a copper wire from the switch, and an aluminum wire to the light bulb. The twist was pure copper with aluminum without any terminal blocks, solder, etc.

So the state is as if just now!

Everything is clean, no oxidization and burning. I think this is because it was always dry in the apartment and besides, the switch box was tightly sealed in the wall - that is, air did not penetrate into it.

And therefore, aluminum did not oxidize, and besides, the load on the twist was minimal - only one light bulb was hooked up.

Therefore, if a large current passes through the copper-aluminum connection, then it is better to make a bolted connection as the simplest, more difficult - soldering.

But in this case, I would not recommend using the Vagovsky clamp, it is better to use other terminal blocks where the wires are at least clamped with a screw.

So now you knowhow to connect copper wire to aluminum and if you have to do it - I'm sure you'll make the right choice!

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

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

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 the main competitor - copper.
Another advantage of this material is its lightness. This caused him wide application in power lines where weight is very important.
Well, the last advantage is its resistance to corrosion. Aluminum is almost instantly covered with a resistant 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.

Then came some continuous flaws. 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 able to pass a current almost 2 times greater than a similar aluminum wire.

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 instruction says 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 norms of the PUE, since 2001, the use of aluminum wire for wiring in residential premises is prohibited. Such a ban significantly reduced the use of aluminum wiring in everyday life.

Methods for connecting aluminum wires

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

Compression connection of aluminum wires

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

	The connection of aluminum wires to each other using this type of connection carries one drawback. If you use conventional screw terminals, then with the help of a screw you can completely or partially transfer the soft aluminum core. This will either reduce or completely destroy the contact.
	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 transfer. Therefore, such nozzles provide reliable contact and exclude the possibility of damage to the wire.
	For bolted connections of aluminum wire, special lugs should also be used. They are attached to a wire or cable by crimping and then these lugs are bolted together.
	As for the Wago terminals, everything is much simpler here. This type of connection cannot damage the wire, so these terminal blocks can be used without additional nozzles. This to some extent compensates for their higher price.

Connection of aluminum wires by pressing

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

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 in any case, since the combination of these two materials can lead to the formation of galvanic isolation and, ultimately, the complete destruction of the aluminum conductor.

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Wiring is never complete without connecting wires. The higher the electricity consumption in the home grows, the greater value has the correct connection of electrical wires, which would ensure the requirements for electrical and fire safety. The correct connection of the wires is the level of contact density, as well as the electrochemical compatibility of the metals connected by the wires.

Now in many apartments there is still aluminum wiring. As soon as in such an apartment arises simple task to replace a chandelier or socket, a problem may arise connections of aluminum and copper wires.

It is known that the direct connection of these metals is strictly prohibited and is a gross violation. Direct contact of copper and aluminum is unacceptable due to the incompatibility of these metals. Under the influence of moisture, such a connection becomes unsafe: it can cause a fire.

Dry contact, although a little more reliable, is also unsafe: it will simply break down more slowly. If moisture suddenly gets on such a contact, an accident may occur even with a slight current.

How to connect aluminum and copper wires in such a situation?

There are several ways, here are the main ones according to the PUE:

Using terminal clamps
By screw connection
Using a layer of neutral material
Using welding

Perhaps the most in a simple way will use a layer of neutral material. Acts as a neutral metal lead-tin solder.

Make it very easy

Carefully cut with a clerical knife and remove the insulation from the wires by about 6-7 cm. Do not place the knife perpendicularly, so you can cut the wire core. It is better to do it at an angle, something like sharpening a pencil.
Using a soldering iron, cover the copper wire with solder. To do this, we collect solder on the tip of the soldering iron and dip it in rosin. After the rosin melts, we very quickly draw a sting through the wire.
We make sure that the copper wire is well tinned. The solder should completely cover the wire.
We make twisting of tinned copper and aluminum wires. A good twist should take about 4 cm as a result.

The method is good because it does not require clamps, or if the bolted connection does not fit in the box.

Despite the fact that the method is simple and fast, nevertheless, if the bulkiness of the connection is not a problem, it is better to use a threaded connection, it will be more reliable. Threaded connection of copper and aluminum wires is also quite easy to do. For this type of connection, it is necessary to prepare a spring washer, three plain washers and a nut. If the conductors have a core diameter of up to 2 mm, select the M4 screw.

We remove the insulation for a length of approximately four screw diameters.
We clean the metal to a shine and form rings.
We put a spring washer on the screw, then a simple washer, then a ring of one conductor, a simple washer, a ring of the second conductor, a washer, a nut.
We tighten the screw and tighten everything until the spring washer is straightened and squeeze it about another half a turn.

If the copper wire is stranded, it must first be tinned. Do not forget that such connections must be checked periodically: the optimal frequency is once a year.

When distributing or repairing electrical wiring, when connecting household appliances and a lot of other work is required to connect the conductors. In order for the connection of wires to be reliable and safe, it is necessary to know the features of each of them, where and when, under what conditions they can be used.

Existing methods of connecting conductors

To connect the wires can be done in several ways:

welding is the most reliable way, providing high reliability of the connection, but requiring skills and the presence of a welding machine;
terminal blocks - a simple and fairly reliable connection;
soldering - works well if the currents do not exceed the normative ones and the connection does not heat up to temperatures above the norm (65 ° C);
crimping with sleeves - requires knowledge of technology, special pliers, but the connection is reliable;
the use of spring clips - wago, PPE - quickly installed, subject to operating conditions provide good contact;
bolted connection - easy to perform, usually used in difficult cases - if it is necessary to switch from aluminum to copper and vice versa.

The specific type of connection is selected based on many factors. It is necessary to take into account the material of the conductor, its cross section, the number of cores, the type of insulation, the number of conductors to be connected, as well as the operating conditions. Based on these factors, we will consider each of the types of connections.

Welding – high reliability in all conditions

When connecting wires by welding, the conductors are twisted, and their end is welded. As a result, a ball of metal is formed, which provides a stable and very reliable connection under any conditions. Moreover, it is reliable not only in terms of electrical characteristics, but also mechanically too - the metal of the connected wires after melting forms a monolith and it is impossible to isolate a separate conductor.

Welding - it is important to heat the metal, but not to melt the insulation

The disadvantage of this type of wire connection is that the connection is 100% one-piece. If you need to change something, you need to cut off the fused piece and redo it all over again. Therefore, for such connections, a certain margin of wires is left - in case of a possible alteration.

Other disadvantages include a welding machine, appropriate electrodes, flux and work skills. In addition, welding takes a lot of time, it is necessary to protect surrounding objects, and it is also inconvenient to work with a welder at a height. Therefore, electricians practice this type of connection in exceptional cases. If you are doing “for yourself” and know how to deal well with welding machine, you can practice on scraps. The trick is not to melt the insulation, but to weld the metal.

After cooling, the welding site is isolated. You can use electrical tape, you can use heat shrink tubing.

Crimping connection of wires

For crimping wires, a special aluminum or copper sleeve is required - it is selected based on the size of the twist (beam diameter), and the material is taken the same as that of the conductors. The wires that are bare and cleaned to a shine are twisted, a tube-sleeve is put on them, which is clamped with special tongs.

Both sleeves and pliers are different, there are several types. Each of them has its own rules of use (the number of wires that can be packed into a sleeve), in which you need to be well versed. It is necessary to pack the wires according to certain rules, measure the size of the resulting bundle, and adjust it to the requirements. All in all, a pretty tedious job. Therefore, this type of wire connection is mainly used by professional electricians, and even more often they switch to spring clips.

Terminal blocks

One of the simplest and most reliable wire connections is through terminal blocks. There are several types, but almost everywhere a screw connection is used. There are sockets of different sizes - for different sizes of conductors, with a different number of pairs - from 2 to 20 or more.

The terminal block itself is a plastic case in which a metal socket or plate is soldered. A bare conductor is inserted into this socket or between the plates, clamped with a screw. After the screw is tightened, it is necessary to pull the conductor well - make sure that it is well clamped. Due to the fact that the connection points remain uninsulated, the scope of the terminal blocks is rooms with normal humidity.

The disadvantage of this connection is that due to the plasticity of metals - especially aluminum - the contact weakens over time, which can lead to an increase in the degree of heating and acceleration of oxidation, and this again leads to a decrease in contact. In general, the connection of wires in screw terminal boxes must be tightened periodically.

Advantages - speed, simplicity, low cost, does not require any skills, except perhaps the ability to use a screwdriver. Another important advantage is that you can easily connect wires of different diameters, single-core and stranded, copper and aluminum. There is no direct contact, therefore there are no risks.

Soldering

First, about soldering technology. The connected conductors are cleaned of insulation, cleaned of oxide film to bare metal, twisted, then tinned. To do this, the conductors are heated with a soldering iron, applied to rosin. It should cover the junction completely. Tinned wires are twisted first with fingers, then squeezed using pliers. Soldering flux can be used instead of tinning. They wet the wires well, but after twisting.

Then, in fact, the soldering process begins: the junction is heated with a soldering iron or a narrow-torch burner. When the rosin or flux begins to boil, take some of the solder on the soldering iron tip, bring it into the soldering area, pressing the tip against the conductors. The solder spreads out, filling the gaps between the wires, making a good connection. When using a torch, the solder is simply added little by little to the torch.

Further, after the soldering place has cooled down, according to the technology, it is necessary to wash off the flux residues (they accelerate oxidation), dry the joint, cover it with a special protective varnish, and then insulate it with electrical tape and / or heat shrink tubing.

Now about the advantages and disadvantages of this method of connecting wires. In low-current systems, soldering is one of the most reliable ways to connect wires. But, when wiring electrical wiring in a house or apartment, it is criticized mercilessly. The thing is that the solder has a low melting point. With the periodic passage of high currents through the connection (it happens if the circuit breakers are incorrectly selected or faulty), the solder gradually melts and evaporates. Time after time, the contact gets worse, the connection heats up more and more. If a this process not found, it may well end in a fire.

The second negative point is the low mechanical strength of soldering. The point is again in tin - it is soft. If there are a lot of wires in a soldered joint, and if they are still rigid, when trying to pack them, the conductors often fall out of the solder - the elastic force that pulls them out is too great. Therefore, the connection of conductors by soldering when distributing electricity is not recommended for use: it is inconvenient, long and risky.

Spring terminals for connecting wires

One of the most controversial ways to connect wires is with spring clips. There are several types, but the most common two are wago terminal blocks and PPE caps. Externally and by the method of installation, they are very different, but both designs are based on a spring that creates a strong contact with the wire.

There is controversy about this spring. Opponents of using wago say that the spring will weaken over time, the contact will become worse, the connection will start to heat up more and more, which, again, leads to an even faster decrease in the degree of elasticity of the spring. After some time, the temperature may rise so much that the case (plastic) will melt, but what can happen next is known.

Spring clips for electrical wiring - popular wire connection

In defense of the use of spring clamps for connecting wires, if they are used in accordance with the manufacturer's recommendations, problems are very, very rare. Although there are many fakes of both wago and PPE, as well as an abundance of pictures of them in a melted form. But, at the same time, many use them, and, under normal operating conditions, they work for years without any complaints.

Clips for wires wago

They appeared on our market a few years ago and made a lot of noise: with their help, the connection is very fast and easy, while it has high reliability. The manufacturer has specific recommendations for the use of this product:

Inside these devices there is a metal plate, which provides the proper degree of contact. The shape and its parameters of the plates were developed and tested specifically. The tests were carried out on a vibration stand for many hours, then heated-cooled. After that, the electrical parameters of the connection were checked. All tests were passed as "excellent" and branded products always show themselves as "five".

In general, Wago's product range is very wide, but for wiring or connecting home appliances, lighting fixtures, use two versions of wire clamps: the 222 series (detachable) with the ability to remake or change the connection and the 773 and 273 series - which are called one-piece.

Detachable

Spring clamps for electrical wiring Wago 222 series has a certain number of contact pads - from two to five - and the same number of flags-clamps. Before starting the connection, the flags are raised up, the conductors stripped of insulation are inserted into them (up to the stop), after which the flag is lowered. At this point, the connection is considered complete.

wago wire connectors - connection methods

If necessary, you can remake the connection - raise the locking flag and remove the conductor. Convenient, fast and reliable.

The 222 vago series can be used to connect two or three, even five conductors made of copper or aluminum (you can connect different metals in one terminal). Wires can be solid or stranded, but with rigid wires. The maximum section is 2.5 mm 2. Soft stranded wires can be connected with a cross section from 0.08 mm 2 to 4 mm 2.

One-piece

There is another type of clamps that does not provide for the possibility of redoing the connection of wires - the 773 and 273 series. When using these terminals, the work is generally seconds: the stripped wire is inserted into the appropriate socket. The spring present there clamps it, providing contact with the plate. All.

These spring-loaded wire clamps can be used to connect solid aluminum or copper wires with a cross-sectional area from 0.75 mm2 to 2.5 mm2, stranded wires with rigid wires from 1.5 mm2 to 2.5 mm2. Soft stranded conductors cannot be connected using such connectors.

To improve contact, before connecting the wires, it is necessary to clean the oxide film. To prevent further oxidation, wago manufacturers also produce contact paste. It fills the inside of the clamp and it itself corrodes the oxide film, and then protects the wires from further oxidation. In this case, only highly oxidized, dark conductors need to be pre-stripped, and the clamp body is filled with paste.

By the way, manufacturers say that, if desired, the wire can be pulled out of the clamp. To do this, they take the wire with one hand, hold the terminal box with the other and rotate them back and forth with a small range, in opposite directions, stretching in different directions.

Clips for lamps (construction and installation terminals for lamps)

For quick and convenient connection of lamps or sconces, wago has special terminals of the 224 series. With their help, you can connect aluminum or copper wires of different sections and types (solid or stranded with rigid wires). Rated voltage of this connection is 400 V, rated current:

for copper conductors - 24 A
16 A for aluminum.

Cross-section of connected conductors on the mounting side:

copper 1.0 ÷ 2.5 mm2 - single-core;
aluminum 2.5 mm2 - single-core.

Cross-section of connected conductors from the chandelier/sconce side: copper 0.5 ÷ 2.5 mm2 - single-core, stranded, tin-plated, crimped.

When connecting copper wires, the use of contact paste is mandatory, and aluminum wires must be manually stripped to bare metal.

This product has two drawbacks. First, the price of original terminals is high. The second - there are a lot of fakes at a lower price, but their quality is much lower and it is they who burn and melt. Therefore, despite the high cost, it is better to buy original products.

PPE caps

PPE caps (stands for "connecting insulating clips") are very easy to use devices. This is a plastic case, inside of which there is a spring that has a conical shape. Conductors stripped of insulation are inserted into the cap, the cap is scrolled clockwise several times. You will feel that it has stopped scrolling, which means the connection is ready.

How to make a wire connection using PPE

These conductor connectors are produced by many manufacturers, there are different sizes, for different diameters and the number of connected conductors. In order for the wire connection to be reliable, the size must be selected correctly, and for this it is necessary to understand the markings.

After the letters of the PPE comes a few numbers. Depending on the manufacturer, the number of digits varies, but they mean the same thing. For example, there is this type of marking: PPE-1 1.5-3.5 or PPE-2 4.5-12. In this case, the number immediately following the letters indicates the case type. "1" is set if the body is an ordinary cone, on the surface of which grooves can be applied - for a better grip. If there is a PPE-2, then there are small protrusions on the case, which are convenient to take with your fingers and twist.

All other figures reflect the total cross section of all conductors that can be connected using this particular PPE cap.

For example, PPE-1 2.0-4.0. This means that the body of the connecting cap is ordinary, cone-shaped. With it, you can connect two conductors with cross section not less than 0.5 mm 2 (in total they give 1 mm, which corresponds to minimum requirements- see table). Maximum this cap includes conductors, overall cross section which should not be more than 4 mm 2.

Connecting wires using PPE caps

In the second marking option, after the PPE abbreviation, there is only a number from 1 to 5. In this case, you just need to remember which one is useful for which wire section. The data is in another table.

PPE caps and their parameters

By the way, only copper wires can be connected with PPE caps - aluminum conductors, as a rule, are thicker than the maximum allowable for these connectors.

Bolted connection

This connection is assembled from a bolt of any diameter, a suitable nut and one, or better three, washers. It assembles quickly and easily, serves quite a long time and is reliable.

First, the conductors are stripped of insulation, if necessary, the upper oxidized layer is removed. Further, a loop is formed from the cleaned part, the inner diameter of which is equal to the diameter of the bolt. To make it easier, you can wrap the wire around the bolt and twist it (the middle option in the right picture). After all this is assembled in this order:

A washer is put on the bolt.
One of the conductors.
Second puck.
Another conductor.
Third puck.
Screw.

The connection is tightened first by hand, then with the help of keys (you can take pliers). That's all, the connection is ready. It is used mainly if it is necessary to make a connection of wires from copper and aluminum, it can also be used when connecting conductors of different diameters.

How to connect aluminum and copper conductors

By the way, let us recall why it is impossible to directly connect copper and aluminum wires. There are two reasons:

Such a connection is very hot, which in itself is very bad.
Over time, contact weakens. This is because aluminum has a lower electrical conductivity than copper, and as a result, when the same currents are passed, it heats up more. When heated, it expands more, squeezing out the copper conductor - the connection gets worse, it heats up more and more.

To avoid such troubles, copper and aluminum conductors are connected using:

terminal blocks;
wago;
bolted connection;
branch clamps (make wire connections on the street).

Other types of connectors cannot be used.

How to connect wires of different diameters

If it is necessary to connect conductors having different diameters, twisting must not be present to obtain good contact. So you can use the following types:

terminal blocks;
wago;
bolted connection.

When repairing (even if only cosmetic), we often face the need to put electrical wiring in order. 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 where the main problem lies: very often the old wires are made of aluminum, and you only have a piece to replace. Let's make a reservation right away 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 them, so as not to become the culprit of a short circuit and a fire?

Why can't you do that?

In order for you to fully realize the danger of such actions, you should talk about why copper and aluminum wires cannot be twisted. It is necessary to remember physics and chemistry.

Do you remember what Roughly speaking, this is how you can call 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 excluded. Yes, even the twist to the outlet, which is constantly used to connect a kettle or other powerful appliance, will not fall apart in a couple of hours, but troubles await you for sure.

Judge for yourself: over time, the materials of the wires are gradually destroyed, the resistance is constantly increasing. Accordingly, the twisting point begins to heat up very much when a powerful current consumer 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 join aluminum and copper wires for a long time. How to connect them if there is an emergency? Agree, in the country it is far from always possible to visit an electrical goods store!

We repeat once again 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 wires. This is the easiest, fastest and safest way by which even the most inexperienced electrician can join the wires. Consider the most common constructive types.

"Nuts"

The oldest and most proven way are called nuts. As you can understand, they got the nickname because of their specific shape. 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 necessary to cut the central line to insert the second wire. To do this, you just need to peel off the insulation in the right place, and then clamp this area between two "nut" plates. A drain 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 WAGO abbreviation. 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 internal space of this connection is filled with a special lubricant, which prevents oxidation and galvanic reaction between different types metals. But! We could recommend the use of such devices 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 become very hot, as a result of which the terminal materials will begin to break down. It is not surprising that WAGO is most often used when working with lighting fixtures.

Terminal blocks

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

Here again lies the rub. 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 quite suitable for this purpose. If the thickness of the insulating plate is normal, then it will withstand even very high loads without problems. But remember that it is highly recommended not to mount indoors with high humidity. There is no insulating lubricant in them, so the formation of a galvanic couple is not excluded.

What other ways to connect wires exist? Let's figure it out.

Bolted fasteners

This mounting method is also great when you need to mate copper and aluminum. The wires are clamped with a bolt, and between the two metals it is necessary to put a washer made of high-quality anodized steel. Remember that this type of connection must be checked for strength at least twice a year. If such an articulation 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, it is quite possible, but some important conditions must be met.

We will not talk about copper for a long time, since there should be no difficulties in this matter. But with aluminum there will be problems. Their cause is an amalgam, which instantly forms on the surface of this metal when it enters an oxygen environment. It is surprisingly resistant 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 to remove this annoying film? First you will have to prepare a saturated solution of copper sulfate, a Krona battery 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 onto it.

Attach aluminum to the negative pole of the battery, and a piece of copper wire to the positive pole. Lower its end into After a while, a fairly decent layer of copper will settle on aluminum, on which you can easily solder the wire you need without any problems.

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

Important!

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

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

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 cores may well come out of the connection. The remaining part of the wire will have a very high load, as a result of which a fire may well occur.
It is very important to choose the terminal exactly for the cross section of the wire you are using. The wire will simply fall out of a too narrow or wide channel, and this is fraught with unpleasant consequences.
Don't press! In most cases, brass is used in terminals and sleeves, and this material is characterized by increased fragility.
Look carefully at the marking, which indicates the maximum allowable current. 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! Manufacturers "Tridonik", "ABB", "Verit" have proven themselves well.

And what about the multicore option?

If you carefully read the article, you already know very well that stranded wires should not be clamped. But what about when you need to connect them to a thick aluminum outlet, but you don’t have a soldering iron, blue vitriol 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 designed to solve this kind of problem.

Sleeve connections

In specialized stores for electricians, you can easily find sleeves specially designed for normal connection. In appearance, they look like miniature tournament spears of knights: behind a protective plastic cap there 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 crimping (you can use the most common pliers). The resulting tip is inserted into the terminal.

So you can easily connect the 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, making twists among professional electricians is considered bad manners and almost a violation of professional ethics, but anything happens in life, and therefore no one is immune from the need to make such a connection.

What advice can be given in this case? Let's start with the fact that the twisting of aluminum and copper wires is allowed only after a thorough cleaning of the aluminum section. If the copper wire is presented in stranded 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 off the wires. It is recommended to close its ends with a special insulating cap, which can be bought in almost every hardware store.

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

In a word, although it is not recommended by professional electricians to make a connection between copper and aluminum wires, using the simplest means, you can quite do it without exposing your house to fire hazard.