Connection of aluminum and copper wires. Connection of aluminum and copper wires to each other Adapters for wires from aluminum to copper

In residential buildings that were built in Soviet times, electrical wiring was carried out with aluminum wires. Professional electricians prefer to make a modern household network with copper wires. Therefore, whether we like it or not, we often face such a problem as connecting copper and aluminum wire. Do not listen to those who will tell you that this cannot be done categorically. Of course, not all methods are suitable for this case, however, connecting electrical aluminum and copper wires is a completely solvable task. The main thing is to do everything right.

These two metals have different chemical properties, which affects the quality of their connection. But there were smart heads who figured out how to connect two conductors, while excluding direct contact between them.

We will consider all the existing options for how copper and aluminum wire can be connected, but first, let's figure out why this cannot be done with ordinary twisting and what is the reason for this incompatibility?

Reasons for incompatibility

The main reasons for the undesirable connection between these two metals lies in the aluminum wire.

the result of twisting copper and aluminum - overheating of the connection, melting of the insulation, the possibility of fire

There are three reasons, but they all lead to the same result - over time, the contact connection of the wires weakens, starts to overheat, the insulation melts and a short circuit occurs.

Aluminum wire has the ability to oxidize under the influence of moisture in the air. When in contact with copper, this happens much faster. In the oxide layer, the resistivity value is greater than that of the aluminum metal itself, which leads to excessive heating of the conductor.
Compared to copper conductor, aluminum is softer and has less electrical conductivity, due to which it heats up more. During operation, the conductors heat up and cool down many times, resulting in several cycles of expansion and contraction. But aluminum and copper have a big difference in the magnitude of linear expansion, so a change in temperature leads to a weakening of the contact connection, and weak contact is always the cause of strong heating.
The third reason is that copper and aluminum are galvanically incompatible. If you twist them, then when an electric current passes through such a node, even with minimal humidity, a chemical electrolysis reaction will occur. It, in turn, causes corrosion, as a result of which the contact connection is again broken, and as a result, heating, melting of the insulation, short circuit, fire.

Bolted connection

Bolted connection of aluminum wires with copper is considered the most affordable, simple, fast and reliable. To work, you will need a bolt, nut, some steel washers and a wrench.

Of course, it is unlikely that you will be able to use this method to connect wires in an apartment junction box, because now they are produced in miniature sizes, and the resulting electrical assembly will be very cumbersome. But if there are still Soviet-era boxes in your house or when you need to make a connection in a switchboard, then such a bolted method is best suited. In general, it is considered an ideal option when it is necessary to switch absolutely incompatible cores - with different cross-sections, made of different materials, stranded with single-core.

It is important to know that using the bolt method you can connect more than two conductors (their number depends on how long the bolt is long enough).

You will need to do the following:

Strip each connected wire or cable from the insulating layer by 2-2.5 cm.
From the stripped tips, form rings according to the diameter of the bolt so that they can be easily put on it.
Now take a bolt, put a washer on it, then a copper conductor ring, another washer, an aluminum conductor ring, a washer and securely tighten everything with a nut.
Insulate the connection with electrical tape.

Most importantly, do not forget to place an intermediate washer between the aluminum and copper wires. If you connect several different conductors, then you can not put an intermediate washer between the cores of the same metal.

Another advantage of this connection is that it is detachable. At any time, you can unwind it and, if necessary, connect additional wires.

How to properly bolt the wires is shown in detail in this video:

Clamp "Nut"

Another good way to connect copper and aluminum wires is to use walnut clamps. It is more correct to call this device a branch clamp. It was already electricians who called him "nut" because of the resemblance.

It is a dielectric polycarbonate case, inside of which there is a metal core (or core). The core is two dies, each of which has a groove for a certain section of the conductor, and an intermediate plate, all this is interconnected by bolts.

Such clamps are sold in any electrical goods store, they have different types, which depend on the cross section of the wires to be connected. The disadvantage of such a device is its non-tightness, that is, there is the possibility of moisture, dust and even small litter. For the reliability and quality of the connection, it is better to wrap the “nut” with insulating tape on top.

The process of connecting wires using such a compression is as follows:

Disassemble the clamp housing, to do this, pry and remove the retaining rings with a thin screwdriver.
On the wires to be connected, strip the insulating layer to the length of the dies.
Unscrew the fixing bolts and insert the bare conductors into the die slots.
Tighten the bolts, position the plate in the compression housing.
Close the housing and put on the retaining rings.

A practical example of using a walnut clamp is shown in this video:

Terminal block

A cheap and easy solution to the question of how to connect aluminum wires to copper is to use terminal blocks. Buying them now is not a problem at all, moreover, you can buy not a whole section, but ask the seller to cut off the required number of cells. Terminal blocks are sold in different sizes, depending on the cross section of the conductors connected to them.

What is such a block? This is a transparent polyethylene frame designed for several cells at once. Inside each cell there is a tubular brass sleeve. From opposite sides, it is necessary to insert the ends of the wires to be connected into this sleeve and clamp it with two screws.

The use of terminal blocks is very convenient because it is always possible to cut exactly as many cells from it as how many pairs of wires need to be connected, for example, in one junction box.

Using the terminal blocks is very simple:

Unscrew one clamping screw, thereby freeing one side of the sleeve for the passage of the conductor into it.
On the strands of aluminum wire, strip the insulation to a length of 5 mm. Insert it into the terminal, tighten the screw, thereby pressing the conductor to the sleeve. The screw should be tightened firmly, but do not be too zealous, so as not to break the core.
Do the same operations with the copper wire, inserting it into the sleeve from the opposite side.

Why do you have to do everything in order? After all, you can immediately unscrew the two screws, insert the wires and tighten. This is to ensure that the copper and aluminum wires do not touch each other inside the brass sleeve.

As you can see, the advantages of terminal blocks are the simplicity and speed of their application. This connection method refers to detachable, if necessary, you can pull out one conductor and replace it with another.

Terminal blocks are not quite suitable for connecting stranded conductors in them. In order to do this, you must first use the end sleeves that will compress the bundle of cores.

There is another feature in the use of terminal blocks. Under the pressure of the screw at room temperature, aluminum can flow. Therefore, a periodic revision of the terminal and tightening of the contact connection, where the aluminum wire is fixed, will be required. If this is neglected, the aluminum conductor in the terminal block will loosen, the contact will weaken, it will start to heat up and spark, which may result in a fire.

How to connect the wires using the terminal block is shown in this video:

Self-clamping terminals

Even faster and easier to connect aluminum and copper conductors in self-clamping terminals.

The stripped conductors must be inserted into the terminal holes until they stop. There they will automatically be fixed with the help of pressure plates (it will firmly press the conductor to the tinned bar). Thanks to the transparent housing of the terminal block, it is possible to check whether the core has completely entered the terminal. The disadvantage of such devices is that they are disposable.

If you want a reusable clamp, use lever-type terminals. The lever rises and releases the entrance to the hole into which it is necessary to insert the stripped core. After that, the lever is lowered back, thereby fixing the conductor in the terminal. This connection is detachable, if necessary, the lever rises, and the wire is taken out of the terminal.

WAGO self-clamping terminals have proven themselves in the best way on the electrical goods market. The manufacturer produces a special series of terminals in which there is an Alu-plus contact paste. This substance protects the contact junction of aluminum and copper from the manifestation of electrolytic corrosion processes. These terminals can be distinguished by a special marking on the package "Al Cu".

Using these clamps is also extremely simple. The clamp itself indicates how long it is necessary to strip the insulating layer of the conductor.

The advantages and disadvantages of using WAGO terminal blocks are described in this video:

Twisted connection

Twisting copper and aluminum wires is not recommended. If you can’t do without this, then first you should tin the copper conductor, that is, cover it with lead-tin solder. So you exclude the possibility of direct interaction of aluminum and copper.

Do not forget that aluminum is very soft and brittle, it can break even under slight loads, so twist very carefully. Do not forget to insulate the connection properly, in this case it is best to use a heat-shrinkable tube.

We tried to tell you in detail whether it is possible to connect aluminum and copper wires together, as well as how to do it efficiently and reliably. Choose the most suitable method for yourself, depending on where this connection will be switched and operated.

Many, probably, faced such a problem when the twisting of wires begins to spark and knock out machines. Naturally, this is unpleasant and poses a great security risk. Using wires from various materials in a home electrical network, you should clearly know how to connect copper and aluminum wire and do it right. Indeed, with direct contact, copper and aluminum are oxidized, violating the quality and integrity of the twist.

Any conductor (copper, aluminum, steel and others) has a certain electrochemical potential. When the moisture in the air interacts with oxygen, electrochemical corrosion occurs in the resulting short-circuited galvanic cell. This reaction leads to a deterioration in the electrical conductivity of the wire. In this case, it is necessary to take additional measures to protect the connections.

The table below defines the potentials of the various conductors. Knowing them, you can choose the right materials that are well connected to each other.

Metal	Copper, its alloys	Lead-tin solder	Aluminum	Duralumin	Steel	stainless steel steel	Zinc coating	Chrome plating	Silver	Carbon (graphite)	Gold Platinum
Copper, its alloys	0,00	0,25	0,65	0,35	0,45	0,10	0,85	0,20	0,25	0,35	0,40
Lead-ol. solder	0,25	0,00	0,40	0,10	0,20	0,15	0,60	0,05	0,50	0,60	0,65
Aluminum	0,65	0,40	0,00	0,30	0,20	0,55	0,20	0,45	0,90	1,00	1,05
Duralumin	0,35	0,10	0,30	0,00	0,10	0,25	0,50	0,15	0,60	0,70	0,75
mild steel	0,45	0,20	0,20	0,10	0,00	0,35	0,40	0,25	0,70	0,80	0,85
stainless steel steel	0,10	0,15	0,55	0,25	0,35	0,00	0,75	0,10	0,35	0,45	0,50
Zinc coating	0,85	0,60	0,20	0,50	0,40	0,75	0,00	0,65	1,10	1,20	1,25
Chrome plating	0,20	0,05	0,45	0,15	0,25	0,10	0,65	0,00	0,45	0,55	0,60
Silver	0,25	0,50	0,90	0,60	0,70	0,35	1,10	0,45	0,00	0,10	0,15
Carbon (graphite)	0,35	0,60	1,00	0,70	0,80	0,45	1,20	0,55	0,10	0,00	0,05
Gold Platinum	0,40	0,65	1,05	0,75	0,85	0,50	1,25	0,60	0,15	0,05	0,00

According to the requirements of the standards, mechanical connection between materials is allowed, the electrochemical potential (voltage) between which does not exceed 0.6 mV. Therefore, a direct connection of copper and aluminum is unacceptable - the electromechanical potential in this case is 0.65 mV, which is 0.05 mV more than the maximum norm. Therefore, it is necessary to choose a kind of gasket between these materials, which optimizes the tension in the bundle.

Considering a copper wire, the best connection option for it would be copper itself and steel (potential 0.1 mV). Likewise with aluminum. Accordingly, in order to connect the copper and aluminum wire correctly, you need to add a gasket (washer) made of steel between the conductors. Also, according to the table, you can choose other combinations of connections.

Having dealt with the electrochemical corrosion of the connected metals, let's move on to considering the main methods for connecting electrical wires.

Twisted connection

Twisting is the most common but less reliable way to connect wires.

Many resort to this method because of the simplicity and lack of appropriate qualifications. But you need to know that with fluctuations in ambient temperature, due to the linear expansion of metals, the following occurs:

A gap is formed between the wires in the twist.
The contact resistance of the conductors increases.
Heat starts to be released.
The wires oxidize, and contact is completely broken over time.

With the aim of obtaining a more reliable contact, it is better to refuse to use twisting. But, if you still stop at this connection method, you should adhere to the following rules:

The different conductors must wrap well around each other.
Measures are required for additional sealing of the twist. To do this, you can use any waterproof protective varnish.
The optimal connection of copper and aluminum conductors will be obtained if the ends are pre-tinned with solder.

The number of turns in the twist must be at least three (for a thick core) and at least five for a thin one (with a diameter of less than 1 mm).

Threaded wire connection

The next acceptable type of connection is threaded with screws and nuts. It is the most reliable and is able to provide good contact throughout the life of the wiring.

Limiting itself to a long thread, you can easily connect and disassemble any number of conductors:

From different metal (for example, copper and aluminum).
Various thickness (core diameter).
Multi-core and single-core.

Use intermediate (spring) washers made of steel to avoid direct contact of copper and aluminum wires.

Consider the steps for creating a threaded connection:

It is necessary to remove from the wire an insulating layer of sufficient length to crimp the live thread of the bolt.
Oxidized areas must be cleaned and degreased. And using a stranded conductor, it must first be tinned.
Then a washer - a copper core (as an example) - a washer - an aluminum core - a washer are installed alternately on the screw. Washers must be steel.
Finally, the whole structure is fixed with a nut.

To prevent excessive crimping of the wires, a spring washer must be installed in front of the first washer. When the nut straightens out while screwing in, the connection will be optimally fixed.

Terminal block connection

Connecting wires using a terminal block is inferior in reliability to connecting with a screw and a nut and has, perhaps, the only advantage:

Simplifies the process of connecting wires (aluminum, copper and others in any combination).

To create a bundle of conductors in this way, the ends of the cores are stripped of insulation to a length of 4 - 8 mm (depending on the diameter), inserted into the hole and clamped with the supplied screws.

Terminal blocks should never be used in critical and powerful areas. Laying in the plaster under the finishing layer is also not the best option.
It is acceptable to use it in viewing areas (in junction boxes) and in conjunction with low-power devices (lamps, chandeliers).
When fixing the cores, the screw must be firmly clamped. This will prevent loose contacts.
When using conductors of various metals, please note that an excessively bare core may have contact with a core threaded from the other side. In this case, partial oxidation and bond weakening will occur.

As an additional precaution, the connection made by the terminal block is recommended to be additionally wrapped with insulating tape. This is due to the fact that a loose contact can lead to an accidental release of a live conductor.

Connection using terminal blocks

Connection using WAGO terminal blocks

The most common type of this connection is terminal blocks with spring clips from the German manufacturer Wago (Vago). They are designed to connect any kind of solid wires (tinned stranded) with a cross section of 1.5 to 2.5 mm².

There are main types of terminal blocks:

Disposable. In this case, the wire is fixed in a permanent connection.
Reusable application. The lever on the body of the product allows you to repeatedly fix the cores.

The use of these connectors is justified:

When connecting electrical appliances (chandeliers, spotlights).
When connecting wiring in junction boxes. It is necessary to take into account the load on the lines of the home electrical network and select the terminal blocks of the appropriate rating.

As with the methods discussed above, the use of Vago spring terminal blocks is justified when connecting copper and aluminum wires. To do this, it is enough to remove the insulation from the conductor by 8 - 10 mm. and insert it into the clamp.

Having studied the question of how to connect copper and aluminum wire, you can apply the knowledge gained in practice without doubting the reliability of the connection. You just need to choose one of the considered methods.

powerhouse.ru

Method of connecting copper and aluminum wire

Hello dear readers of the site sesaga.ru. I wrote this short post with the assistance of my neighbor Vladimir Sh, for which special thanks to him.

The other day Vladimir contacted me with a request to see his outlet. A year after the repair, the outlet began to smell, and over time it also began to warm up. Well, when the socket sparkled, he began to sound the alarm.

Everything turned out to be simple. The wiring around the apartment was made with aluminum wire, and the newly introduced and additional wiring was already carried out with copper wire, and copper was connected to aluminum with ordinary twisting without any adapters and devices.

Never bond aluminum and copper together. Fire not ruled out.

It was necessary to separate the copper from the aluminum, but still leave the connection. There was nothing suitable at hand, and the first thing that came to mind was to make a bolted connection: cheap and cheerful.

First of all, we break the connection, and if possible, then we bite off the damaged parts of copper and aluminum. But, in our case, the wires turned out to be short, and we cut off only the most, most damaged parts, and cleaned the rest.

To restore the connection, and at the same time separate copper from aluminum, we need:

1 . Two bolts with a diameter of 4 or 5mm;
2 . Four nuts with a diameter of 4 or 5mm;
3 . Eight washers of suitable internal diameter;
4 . Insulating tape;
5 . Copper two-core wire with a cross section of 2.5 squares and a length of about 40 cm.

We remove the insulation from the aluminum wire and make a half ring of such a diameter that the bolt enters.

We put a washer on the bolt, and together with the washer we insert the aluminum wire into the half ring.

From above, close the semi-ring with a washer and well tighten with a nut.
Now the aluminum wire must be extended with a piece of copper, so that further connection can be made between copper and copper.

We take a piece of copper wire 15 - 20 cm long, make a half ring, put it on the same bolt, and between two washers well tighten with a nut.

You will get such a "sandwich".

Now we isolate this “sandwich” and hide it in the depths of the box.

In the same way, we make the second bolted connection.
And now any copper can be freely screwed to the resulting two ends.

Let's restore the schema.

The twists made can be irradiated, or you can not irradiate.
Next, we isolate the twists, remove the inside of the box and breed so that they do not interfere with the outlet.

Well, it remains to connect and fix the outlet on the wall.

In such a simple, but at the same time effective way, we bonded copper to aluminum, and at the same time, eliminated a malfunction that could lead to unknown consequences.
Good luck!

sesaga.ru

Until now, there is a considerable number of premises where electrical wiring is made of aluminum. At the same time, modern systems are based on the use of copper as a conductor. That is why the problem of joining wires from these dissimilar materials is relevant. How to join copper and aluminum wires will be discussed below.

Electrochemical corrosion

It is often possible to meet statements that it is undesirable to combine copper and aluminum into one. From the point of view of material compatibility, these are fair statements. What about combining copper and zinc or steel and silver? There are many options for metal pairs, and remembering which ones are compatible with each other and which are not is difficult. To simplify the task, there are special tables, one of which is presented below.

Table of electrochemical potentials (mV) that occur between connected conductors.

To understand the issue, you need to know what processes occur when different conductors of electricity touch each other. If there is no humidity, the contacts will be reliable anyway. However, in practice, this situation is impossible, since moisture is always present in the atmosphere, which breaks the connections.

Each conductor of electricity has a certain electrochemical potential. This circumstance is used by a person for practical purposes, for example, batteries and batteries work on the basis of different potentials.

When moisture gets on the contacting metal surfaces, a short-circuited galvanic medium occurs, and one of the electrodes is deformed. In the same way, one of the two metals is destroyed. Thus, in order to determine the compatibility of metals, it is necessary to have information about the electrochemical potential of all materials involved in the reaction.

What happens if copper is connected directly to aluminum

According to technical regulations, mechanical joining of metals is allowed if the electrochemical voltage between the two materials is not higher than 0.6 mV. For example, from the table above, it can be established that in the case of a combination of aluminum and copper, the electrochemical potential is 0.65 mV, which is much higher than when the same copper is joined with duralumin (0.20 mV).

And, nevertheless, if it is very necessary, then it is possible to combine such not quite compatible materials, which include copper and aluminum. How to connect copper and aluminum wires will be discussed below.

Overview of connection methods

There are several ways to connect aluminum and copper wires. Moreover, in each of the described cases, special devices will be needed. Let's consider each type of docking separately.

Bolted connection

This type of connection is the most common, since it is simple and cheap. When done correctly, a wired connection with nuts and bolts will provide reliable contact for the life of the wiring and electrical appliances. In addition, you can always disassemble the connection, attach additional conductors, etc. Thanks to the threaded connection, the relevance of the electrochemical incompatibility of metals is lost, it becomes possible to join aluminum and copper, thick and thin wires, stranded and single-core. It is important to avoid direct contact between dissimilar materials by making gaskets from spring washers.

To do the job, you will need a bolt and nut, as well as a washer (it must be made of anodized steel).

The connection is made as follows:

We remove the insulating layer from the wires for a short length (about four bolt diameters). We also perform stripping of the conductor, especially if its cores have undergone oxidation. We form rings from the veins.
First, an aluminum conductor is screwed to the bolt in one girth.
We put on the puck.
Now it's the turn of the copper conductor. We also screw it in one turn.
Next, screw the nut in such a way as to achieve a secure connection.

Note! If docking is carried out for operation in a room where, according to technical conditions, there is vibration, an additional nut will be required for a quality result.

Terminals

There are several options for terminal connections. One option is the so-called "nuts". Such an unusual name for terminal blocks comes from their external resemblance to nuts. There are several varieties of "nut" terminals available.

The model, which is the most primitive in its structure, has three delimiting plates inside. Conductors are located between the plates. Thus, it is possible to avoid direct contacts between dissimilar materials. At the same time, "nuts" allow you to save the supply circuit of the electrical circuit.

To achieve the integrity of the circuit, it is necessary to strip the supply conductor from the insulating layer, unscrew a couple of bolts, install a bare wire between the plates and tighten the bolts again. Remove the insulator from the outlet ends, and then direct the wires into holes located perpendicular to the inlet channel. Further, the conductors are fixed between other delimiting plates.

There is also a more complex model on the market, the design of which is designed in such a way that there is no need for cutting conductors. The fact is that the plates of the device contain teeth, which, when squeezed by bolts, simply break the insulating layer. The described docking option is considered very reliable.

There is another option for terminal blocks - ordinary pads. The device is a bar with terminals. To connect two dissimilar materials, you need to strip their ends and send the wires to the terminals. The ends are fixed with bolts that are located over the terminal holes.

Wago terminal blocks

The connection of copper and aluminum wires can be done using Wago terminal blocks. This device belongs to the aforementioned terminals, however, Wago pads should be described in a little more detail due to their popularity among buyers.

Wago is made in two versions: disposable with a non-removable wire and reusable - with a lever that allows you to repeatedly install and remove the conductor.

Wago is used for all types of solid wires, the cross section of which is between 1.5 and 2.5 square millimeters. The block can be used in distribution boxes with a current of up to 24 amperes. However, in practice, it is believed that 10 amperes is more than enough and large figures will lead to overheating.

To connect the conductors, it is necessary to force one of them into the shoe hole, as a result of which it will be securely fixed there. To remove the conductor from the hole, you will also need to apply force. Please note that removing the wire from the disposable terminal block may deform the contact, so a reliable contact is not guaranteed the next time.

It is much more convenient to use the Wago reusable device. A characteristic feature of such a terminal block is the presence of an orange lever. With the help of such a device, it is possible to dock or disconnect all types of wires with a cross section from 0.08 to 4 square millimeters. Permissible current level - 34 amperes.

To create a connection, you need to remove the insulation from the wire by 8-12 millimeters, raise the lever up, direct the wire into the hole in the terminal block. Next, return the lever to the opposite position, thereby fixing the wire in the terminal.

The only significant drawback of Wago is the higher cost compared to traditional terminals.

Rivets

This method of joining dissimilar conductors resembles a bolted one. However, instead of a nut and a bolt, a rivet is used, which forms a permanent connection. In other words, after fixing, it is no longer possible to remove the rivet without damaging it.

To perform the docking, we clean both conductors from the insulating material, and also bend the wires into rings. Next, we string one of the rings onto the rivet, after that we put on a steel washer, then we string the ring again, but already the second conductor.

The rivet has a cap on one side. Now you need to flatten the second side, thus forming a second hat, which will act as a fastener. The deformation of the rivet is carried out either with a hammer or with a special tool similar to pliers. The method of joining with rivets allows you to get a very high-quality connection.

soldering iron

If desired, you can solder two dissimilar metals. However, this will require compliance with some technological nuances.

As for copper, there will be no problems with soldering, but with aluminum the situation is more complicated. The fact is that as a result of soldering and under the influence of oxygen, an amalgam appears on the metal surface. This alloy-film is incredibly chemically resistant, which means it does not adhere to solder. To eliminate the film, you will need a solution of copper sulfate, a Krona battery and a piece of copper wire.

On the aluminum wire, we clean the soldering area, and after that we apply a little vitriol there. We fix the aluminum wire on the negative pole of the battery, and we fix the copper wire with one end on the positive pole, and put the other end in copper sulfate. After some time, aluminum will be covered with a copper layer, on which you can solder a copper conductor.

Connection quality

In most of the cases considered earlier, rigid fastening of the conductors cleared of the insulating layer will be used. However, when joining copper and aluminum, one important technological nuance must be taken into account: aluminum under the influence of the load acquires plasticity, as experts say, it begins to "flow". As a result of this process, the connection is weakened, and therefore the bolts must be tightened regularly. If the bolts are not tightened in time, the terminal may simply catch fire due to severe overheating.

There are a number of rules, adhering to which, you can achieve a high-quality connection:

Conductors with multiple strands must not be clamped too tightly. In such wires, the cores are too thin, they are easily torn under the influence of compression. The result of the gaps is an overload on the remaining cores, which may cause a fire.
It is important to choose the right terminal, taking into account the cross section of the conductor. If the channel is too narrow, the conductor will not fit, and if it is too wide, it will fall out.
Brass sleeves and terminals are very fragile, so do not overtighten them.
You should carefully consider the marking, where the maximum possible current strength is suggested. Moreover, it is better not to achieve this indicator, limiting yourself to no more than 50% load.

Note! It is not recommended to buy nameless products made in China. Connectors are too important a detail to skimp on. It is best to give preference to products of well-known companies (for example, the Swiss company ABB).

stranded wires

As mentioned earlier, conductors with many strands should not be strongly pinched. To connect stranded wires, sleeves or ordinary twists are most often used. We will discuss these methods in more detail below.

Sleeves

The sleeve is a protective cap made of plastic, under which there is a hollow metal tip. First of all, it is necessary to remove the insulating layer from the conductor. Further, the veins are twisted into one whole, and the resulting "pigtail" is sent to the sleeve. Next, the sleeve is crimped (pliers are suitable for this operation). The tip of the sleeve is inserted into the terminal. To increase the reliability of the connection, the sleeve can be treated with solder.

Twisting

Among professional electricians, twisting is not revered. However, there are situations when twisting is the most convenient way out of the situation (for example, to create a temporary connection or in the absence of the necessary materials).

So, twisting from copper and aluminum is allowed only after a thorough cleaning of the aluminum surface. If the copper conductor has many strands, all available strands must be assembled into one "pigtail". Also, copper must be coated with solder - this will improve contact.

When twisting, it is important to prevent the wires from breaking. The endings are best covered with insulating protective caps, which can be purchased at any hardware store.

Note! Twisting is unacceptable in rooms with humid air.

So, there is nothing complicated in connecting copper and aluminum conductors. You just need to remember the price of a mistake: incorrectly connected wires can cause not only the failure of electrical appliances, but also a fire.

How to connect copper and aluminum wire - an overview of popular methods

220.guru

How to connect copper and aluminum wire correctly?

When partially replacing the wiring, extending the conductor or replacing the burnt area, a wire is used. It happens that in their material they do not match. Then it becomes necessary to connect aluminum wires with copper. There are five ways to do this, and each has its own advantages and disadvantages. Some of them require preliminary preparation of the conductor.

Danger of bad wiring

The industry produces two types of wires for domestic purposes, copper and aluminum. The former have less resistance, which allows using a smaller section for the same load. They are more resistant to mechanical stress, this makes it possible to repeatedly twist, not to be afraid that they will break at the place of the incision. The latter have one advantage - comparative cheapness. But sometimes it plays a key role. What can happen if the junction is of poor quality?

Copper and aluminum have different characteristics, for example, a different coefficient of expansion when heated. When a large current passes through an aluminum conductor, it begins to "flow". If the cores move relative to each other during heating or cooling, this will lead to a gap between them. The gap, in turn, will lead to a discharge (spark). Sparks can cause a fire. Along with this, copper and aluminum begin to oxidize, the resistance between them increases, the voltage drops because of this or may completely disappear. Voltage fluctuations can adversely affect connected devices.

Methods for joining copper to aluminum

There are several connection methods. All of them have their pros and cons. Some require special equipment and skills, others are easy to use. Here are a few of them:

twist;
threaded;
terminal;
one-piece.

Wire twisting

It is strictly forbidden to use twisting in fire hazardous areas. This is the fastest and easiest way. Two or more wires are taken and wrapped around each other. One or more than one strand must not be left straight. There is a rule - thick cores must have at least three turns, thin ones (from 1 mm or less) - five. To reduce the oxidation of the conductor, the copper core is soldered for the length of the twist. The same rule applies to stranded copper cables.

After the twisting has been made, it must be protected from the environment by coating with any waterproof varnish. This is necessary to reduce further over-oxidation. Then it is isolated with electrical tape or special caps, which are sold in the store, and hidden in an insulating case. But even all this does not guarantee that the twist will work flawlessly.

Threaded method

More labor-intensive connection compared to twisting. Requires a tool and some skill. It has greater mechanical strength. On the electrical side, it is better than twisting. Allows you to immediately connect a large number of wires, and of different sections. You can connect both single-core and multi-core.

For connection, a bolt is used, on which conductors are put on in turn. They are pre-cleaned and wrapped in rings. Each core, if they are made of different materials, is laid with a washer. A washer and a spring washer are superimposed on the last conductor. The whole package is tightened with a nut until the spring washer straightens out. Further pressure may break the conductor.

To prevent the washer from cutting the wires, they must be put on in a checkerboard pattern (so that they do not lie on top of each other). If the copper wire is tinned, washers are not needed. The stranded copper wire also needs to be soldered, then it will not disintegrate during compression.

After assembly, measures must be taken to prevent short circuits with neighboring packages. Over time, it is necessary to check the condition of the spring washer, if it is weakened, tighten the nut. Such a connection prevents sparking, allows you to output wires in different directions. If necessary, it can be easily disassembled and assembled without damaging the conductor.

Terminal method

The terminal connection is made in factories. Has an extensive range. Two groups can be distinguished:

pads;
terminal blocks.

pads have different shapes and designs. The bottom line is to attach several wires to one conductor (plate, tetrahedron, etc.), which are inserted into special connectors and pressed with a screw. As a rule, the pads themselves are attached to the base, creating structural rigidity.

The advantage of pads is that no preliminary steps are needed, with the exception of stripping the cores. The connection is fast and does not require any skills. They are indispensable if the conductor is short (connecting a chandelier, restoring a broken wire). If they are located in switchboards, metering boards - they do not require insulation. Since each wire is connected separately, both copper and aluminum wires can be used.

The disadvantages include the following:

less resistant to mechanical stress than a threaded connection;
each block is designed for a conductor of a certain section;
it is impossible to connect wires of large and small diameter at the same time;
take up more space than before.

Terminal blocks have recently found wide application. According to their purpose, they are of two types:

reusable;
for one time use.

reusable the terminal block is a fully insulated block. Instead of screws, a spring plate is used, which is pressed out with a plastic lever. After that, a wire is inserted into the opening. In some embodiments, the plate has teeth, which allows the use of unstripped wires. To pull out the wire, you need to lift the lever again.

One-time have the same principle, but do not have a lever. Designed for single use. If the wire is still pulled out and reinserted, the quality of the connection will be poor.

Advantages:

allows you to very quickly connect aluminum and copper wires to each other;
minimal training required;
ease of use;
the necessary insulation is available.

Disadvantages:

the method is the most sensitive to mechanical stress;
compared to other compounds, it is the most expensive;
sensitive to high current and, according to user comments, does not withstand the regulated load.

One-piece method

Probably the most laborious way. Requires special knowledge and skills. Special tools and fixtures are required. This method includes:

riveted;
soldering.

stave very similar to a threaded connection, with the only difference being that a rivet is used instead of a bolt. The ends of the wires are cleaned of insulation and cleaned with sandpaper. When combining aluminum and copper wires, the latter is tinned. This also applies to copper stranded wire. After that, rings are made a little larger in diameter than the rivet. Finally, when the entire structure is assembled (without intermediate washers), a washer is put on top. All this is compressed by the terminal block. It is insulated in the same way as a threaded one.

Soldering used where high reliability of the connection and its low resistance are needed. It looks like a twist, but the wires are soldered. This cannot be achieved in the usual way for aluminum, so the wires must be prepared.

To do this, you need a solution of copper sulfate, a small non-metallic container, a constant voltage source of 9-24 V. Pour a solution of copper sulfate into the container and lower the previously cleaned conductors to the length of the twist. We connect the copper wire to "+" so that the electrons go from it, and the aluminum wire to "-". Turn on the power source.

The voltage, of course, can be increased, the main thing is that the solution does not boil or there is no overload in the electrical circuit. You can also reduce the voltage, then the process will proceed more slowly. All this works until the aluminum wire is covered with a copper film.

After that, both wires are covered with a layer of tin. A twist is made in 3 turns for a thick wire and 5 for a thin one (less than 1 mm). All this is carefully soldered. It remains to cover them with waterproof varnish, insulate - and the connection is ready.

Advantages:

has an aesthetic appearance;
good mechanical strength;
reliable connection.

Disadvantages:

there is no way to disassemble;
you can only work with removable wires;
purchase of additional equipment;
requires some skills.

Now, knowing all the ways to connect copper and aluminum wires without soldering, you can fix this problem when it occurs.

elektro.guru

How to connect aluminum wires - methods for connecting aluminum and copper wire

Almost every electrician will say and agree that electrical is the science of contacts. In practice, this becomes obvious. A large number of problems in the power supply are formed due to a 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.

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 temperature of aluminum itself. Moreover, if you clean the oxide film mechanically, then after a while it appears again.

If you want to solder aluminum, then this film will prevent the solder from adhering to the core. Also, during welding, the film forms inclusions that adversely affect the quality of the contact. Among other things, aluminum belongs to the category of metals that are characterized by high fluidity and brittleness. As a consequence, the contact must be completely protected against possible mechanical influences. For example, if you connect aluminum with a bolt clamp, then you need to regularly tighten the contact, since aluminum, figuratively speaking, “flows out” from under the contact, which, in turn, weakens.

Are there ways to reliably connect aluminum wire then? Let's take a 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 from insulation by 20 mm. After the vein, it is recommended to clean it with a fine-grained sandpaper. Next, twist the bare core into a ring and insert it into the clamping screw, which should be tightly tightened.

Screw connection kit

The downside 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 place.

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 securely held. There are terminal blocks both disposable and reusable. Disposable are used to connect wires, without further disconnection. The wire is inserted into the hole of the clamp, do not pull it back. As for the reusable connection, the wire is easily pulled out by pressing the special lever holding the wire.

Twisting

In rare cases, aluminum wire can be connected by twisting. It should be noted right away that this method is very unreliable, even though it was used relatively often in Soviet times. 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, such as current load, humidity and temperature. If the temperature rises, the metal expands, which widens the gap between the wires. This can lead to contact resistance, the contact point will heat up and after that oxidation will form and, in the end, the contact will be completely broken. However, this process continues for a long time, so for temporary connections, the twisting method is acceptable.

When joining aluminum in this way, it is important to adhere to the following rules:

The wires should evenly wrap around each other.
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.

Permanent connection

Crimping.
Soldering.
Welding.

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

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

Consider each method of permanent connection separately.

Welding

Fast and reliable connection method. Moreover, this technology is relevant if a large number of connections should 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.
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.

Flux

The drop should be treated with a solvent, and then varnished.
When the varnish is dry, 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, special press tongs and sleeves, which are hollow rods, will be required. For crimping, you clean the ends of the wire, insert them into the sleeve and perform crimping in three places. You can also twist the wires additionally.

Crimping set

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

aluminum and copper wire

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. With an increase in humidity due to this difference, the contact will be destroyed. Moreover, the contact will heat up, which can lead to disastrous consequences.

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

Using these techniques, it is possible to connect aluminum to copper wires.

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

Video

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

kakpravilnosdelat.ru

How to connect copper and aluminum wire

Reasons for incompatibility

The main reasons for the undesirable connection between these two metals lies in the aluminum wire.

the result of twisting copper and aluminum - overheating of the connection, melting of the insulation, the possibility of fire

There are three reasons, but they all lead to the same result - over time, the contact connection of the wires weakens, starts to overheat, the insulation melts and a short circuit occurs.

Aluminum wire has the ability to oxidize under the influence of moisture in the air. When in contact with copper, this happens much faster. In the oxide layer, the resistivity value is greater than that of the aluminum metal itself, which leads to excessive heating of the conductor.
Compared to copper conductor, aluminum is softer and has less electrical conductivity, due to which it heats up more. During operation, the conductors heat up and cool down many times, resulting in several cycles of expansion and contraction. But aluminum and copper have a big difference in the magnitude of linear expansion, so a change in temperature leads to a weakening of the contact connection, and weak contact is always the cause of strong heating.
The third reason is that copper and aluminum are galvanically incompatible. If you twist them, then when an electric current passes through such a node, even with minimal humidity, a chemical electrolysis reaction will occur. It, in turn, causes corrosion, as a result of which the contact connection is again broken, and as a result, heating, melting of the insulation, short circuit, fire.

Bolted connection

Bolted connection of aluminum wires with copper is considered the most affordable, simple, fast and reliable. To work, you will need a bolt, nut, some steel washers and a wrench.

It is important to know that using the bolt method you can connect more than two conductors (their number depends on how long the bolt is long enough).

You will need to do the following:

Strip each connected wire or cable from the insulating layer by 2-2.5 cm.
From the stripped tips, form rings according to the diameter of the bolt so that they can be easily put on it.
Now take a bolt, put a washer on it, then a copper conductor ring, another washer, an aluminum conductor ring, a washer and securely tighten everything with a nut.
Insulate the connection with electrical tape.

Another advantage of this connection is that it is detachable. At any time, you can unwind it and, if necessary, connect additional wires.

How to properly bolt the wires is shown in detail in this video:

Clamp "Nut"

The process of connecting wires using such a compression is as follows:

Disassemble the clamp housing, to do this, pry and remove the retaining rings with a thin screwdriver.
On the wires to be connected, strip the insulating layer to the length of the dies.
Unscrew the fixing bolts and insert the bare conductors into the die slots.
Tighten the bolts, position the plate in the compression housing.
Close the housing and put on the retaining rings.

A practical example of using a walnut clamp is shown in this video:

Terminal block

The use of terminal blocks is very convenient because it is always possible to cut exactly as many cells from it as how many pairs of wires need to be connected, for example, in one junction box.

Using the terminal blocks is very simple:

Unscrew one clamping screw, thereby freeing one side of the sleeve for the passage of the conductor into it.
On the strands of aluminum wire, strip the insulation to a length of 5 mm. Insert it into the terminal, tighten the screw, thereby pressing the conductor to the sleeve. The screw should be tightened firmly, but do not be too zealous, so as not to break the core.
Do the same operations with the copper wire, inserting it into the sleeve from the opposite side.

Terminal blocks are not quite suitable for connecting stranded conductors in them. In order to do this, you must first use the end sleeves that will compress the bundle of cores.

How to connect the wires using the terminal block is shown in this video:

Self-clamping terminals

Even faster and easier to connect aluminum and copper conductors in self-clamping terminals.

Using these clamps is also extremely simple. The clamp itself indicates how long it is necessary to strip the insulating layer of the conductor.

The advantages and disadvantages of using WAGO terminal blocks are described in this video:

Twisted connection

yaelectric.ru

How to connect aluminum and copper wire

When repairing or replacing electrical wiring, a situation often arises when it is necessary to splice aluminum and copper wires. The contact must be very tight, and over a fairly large area. This is due to the fact that a fairly large current will flow here. This situation is especially relevant when it is necessary to splice wires through which electricity is introduced into living quarters. How to connect aluminum and copper wire to each other so that the connection is reliable, efficient? You will find answers in this article.

Figure 1. Simple wire connection methods

Why You Can't Just Twist Aluminum and Copper Wires

Is it possible to connect aluminum and copper wires? With aluminum, you need to work carefully, this is due to the specifics of the metal. It has peculiar characteristics, it oxidizes quickly. At the same time, a strong film of aluminum oxides is formed on its surface. Its strength is indicated by the melting point - it is higher than that of pure aluminum. The film prevents the normal flow of current. A method such as mechanical cleaning does not help - the film layer is still restored.

There are still obstacles to simple splicing - a high level of fragility, strong fluidity. That is, aluminum wire cannot be bent as it pleases. It will just break. With copper, this is much easier to do, since it is more ductile. Chemical processes in the presence of moisture, such as electrochemical corrosion, destroy metals at their points of contact. The reason is that copper and aluminum have different electrochemical potentials. There is a large difference between them, equal to 0.65 mV, it exceeds the maximum permissible value.

That is why it is impossible to connect aluminum and copper wires with a simple twisting method. Many, not knowing this circumstance, still manage to twist. They are attracted by the simplicity of the process, the absence of the need for additional materials, except for insulating tape. At first, such a wire connection will work well. Then, due to the difference in linear expansion coefficients resulting from the diurnal temperature difference, the contact will begin to weaken. This will lead to an increase in resistance, the start of oxidative processes. Subsequently, corrosion destruction will begin.

It must be understood that all of the above will not happen in one day and, perhaps, not in one month. But it will definitely happen. Well, if it ends like this. Because there are cases when fires arise from the spark that appears. How to connect copper and aluminum wires to get a reliable durable contact?

This will require additional equipment. For example, the connection of aluminum and copper wires is possible by twisting, if the copper wire to be connected is first tinned with tin-lead solder. The difference in electrochemical potentials between them is low - 0.25 mV. Solder with aluminum alloys has a potential difference of 0.4 mV. So the twisting method for this case is suitable.

Tinning is mandatory if you have to connect a multi-core cable made of copper with aluminum. You should know that both wires must be wrapped around one another, although they have different degrees of rigidity. You can not wrap one vein around another. The following are methods for twisting and simple connections for wires.

Figure 2. Twisting methods

Connection with threaded devices

This method is the easiest after twisting. True, it requires one bolt, nut, two spring-loaded and three simple washers. Thus, strong connections are obtained, regularly serving for many years. The advantage in this case is the possibility of connecting conductors of different sections, solid, stranded.

The connection of aluminum wires with copper is carried out in the following sequence:

one of the wires is stripped of insulation;
a spring-loaded washer is put on the bolt head, and a simple one on top of it;
bare wiring is wrapped around the bolt thread so that its diameter is slightly larger than the outer diameter of the thread, then it is located above a simple washer;
another simple washer is placed on top;
a ring of another wire with the insulation removed is laid on top of it;
another simple and spring-loaded washer is thrown onto the wire;
all structural elements are firmly connected with a nut.

Figure 3. Threaded connection

Depending on the diameter of the conductors, the size of the bolt thread is selected for the best connection. For example, for a core with a cross section of 2 mm, the thread diameter M4 will be optimal. If the copper conductor is stranded, it would be better to solder it by connecting all the cores into one bundle.

Rivet splicing

Copper and aluminum wires can be connected in another way, where a rivet is used instead of a screw and nut. How to rivet aluminum and copper wire? This will require a rivet, one spring and one plain washers. An aluminum conductor wrapped around it is put on the rivet head. A spring-loaded washer is put on top. Then a tinned copper core is wrapped around the rivet, on which a simple washer is put on.

The riveting process takes place using a special device - a riveter, which you need to have with you. The contact is strong, but such a connection is one-time. If necessary, a branch can be drawn from the threaded interface by increasing one more reliable contact. With a rivet, this upgrade option is not possible.

Sockets and clamps with terminals

This is one of the most convenient devices for connecting copper and aluminum wire. Terminals can connect not only aluminum and copper wiring, but also apply them to other combinations of metals and their alloys. This connection of copper and aluminum conductors has several advantages.

It is possible to connect aluminum and copper wires of different diameters to the terminal block.
It is possible to connect copper stranded wire without solder coating.
In order to connect the wires, it is only necessary to remove the layer of insulation from their ends.
The pads are conveniently fixed in the wiring.

Figure 4. Sockets and clamps with terminals

The wires are clamped by the ends of the screws or special clamping plates. Stranded conductors can be damaged if simply clamped with screws. Plates in this regard are much more practical.

An alternative to the blocks can be spring-type terminal clamps. The terminal blocks of the German company Wago are especially popular. These devices can be disposable or reusable. Are intended for merging of any veins, including copper and aluminum. Connecting conductors to the clamps is much faster and easier than twisting them.

There are no requirements for conductors - they can be made of different alloys, have different diameters. Any combination of sections is possible - from 0.08 mm to 4 mm 2. They just need to be cleaned to a depth of 10 mm. Reusable clamps can fix the conductors, passing through themselves a current of up to 34 amperes. Fixation is made by a special lever, which should be lowered down. In order to pull the core back, the lever must be raised.

Such devices are used to connect chandeliers, wall lighting fixtures. They are convenient to use for wiring inside junction and junction boxes.

External connections

All that is listed above is used for splicing inside buildings. But how to connect copper and aluminum cables from the outside? For this, a special clamping mechanism called "Nutlet" is proposed. The clamp body made of plastic reliably protects the place of splicing and branching of conductors from external influences. For reliable contact, several plates are used, made of a metal that is neutral to copper and aluminum.

Figure 5. Wire connector "Nut"

To remove the insulation, do not use tools such as wire cutters or pliers. Their use can lead to the fact that the cores are damaged. This is especially true for brittle aluminium. Before connecting the wire correctly, it is preferable to strip its cores with a clerical or any other sharp knife. Remember how the pencil is cleaned - the insulation is removed in the same way. In this case, damage to the current-carrying conductors is minimal.
In order to tin a stranded copper conductor, only rosin should be used from fluxes. Materials such as zinc chloride or hydrochloric acid should not be used - over time they will destroy the conductor.
For threaded connections, it is unacceptable to use washers, nuts and bolts made of galvanized materials. This is due to the fact that the difference between the electrochemical potentials of aluminum and zinc is 0.85 mV. This value is even greater than that of a copper-aluminum contact.
For splicing, it is best to purchase terminal blocks and clamps from reputable manufacturers. Let them cost more, but the materials used in the manufacture will provide reliable contact.

Summary

As you can see, there are quite a few ways to connect cables made of different metals. For each of them, you need to follow simple rules in order to get a reliable connection. Of course, for modern electrical wiring it is better to use only copper cables. But even in this case, splicing of different metals may be required at the input.

We have long and universally switched to copper wires in home electrical wiring. But the likelihood of docking with aluminum conductors from the past is still high. This usually occurs when replacing or repairing existing electrical wiring that was previously installed. However, aluminum is also contained in the new SIP wire (self-supporting insulated wire), which is now customary to make connections from the pole to the house. Everything would be fine, but aluminum and copper are not “friends” at the molecular level, and we have to solve this problem on our own. Let's see which method suits you best.

Twisting is not the best method

In the old days, ordinary twisting was used when connecting home wiring wires. This was a familiar procedure, and no additional devices were required at all. Quite often, this method is used now, because it is difficult to refuse simple and quick solutions. If you still have to twist, then try to minimize the risks: the wires must be tightly wrapped around each other. A method is completely unacceptable when one core is straight, and the second wraps around it - such a connection will be initially defective.

In the connection, the number of turns is selected in accordance with the diameters of the cores. If the diameter is less than 1 mm, we make 5-6 turns. When twisting wires of larger diameter, three turns are sufficient. After tight twisting, it is necessary to seal the connection with a protective varnish with waterproof properties.

The easy way with screws

Wires of different materials can be successfully connected using screws and nuts. It is convenient that such a connection, if necessary, is quickly disassembled and redone again. With proper execution, the threaded connection will be quite high quality and durable. The attractiveness of this option is the possibility of simultaneously connecting several wires, the number of which can only be limited by the length of the screw itself.

The screw method is well suited for connecting wires with different numbers of strands and different diameters. The main thing is that there is no conflict approach between wires from different materials. Washers are used for separation. The procedure is simple: we remove the sheath from the cable to the required length, and then we make wire rings according to the diameter of the screw. We sequentially put a spring washer, a ring of wire, a washer, a ring of the next conductor, etc. on the screw rod. At the end of the assembly, tighten the nut until the spring washers are completely straightened.

When there is a rivet on hand

This method of docking resembles a bolted one, but instead of a nut and a bolt, a blind rivet is used, which forms a permanent connection. But after fixing, it will no longer be possible to fix the connection without “surgical” removal of the assembly. From the stripped ends of the wires we make rings with the same diameter as the rivet. In connection we use galvanized washers. Having strung the assembly, we pull out the rivet and we get a very high-quality connection. But it can only be used inside the mounting box.

Connect with terminal block

A fairly popular method of connecting conductors with special terminal blocks, of course, loses to screw in reliability, but it makes it possible to connect wires as quickly and simply as possible. To do this, it is enough to remove the insulation from the connected ends of the wires by about 5 mm, insert them into the terminal block and tighten with a screw. Tighten the aluminum soft wire with little effort.

Terminal blocks are convenient to use when connecting a chandelier to aluminum wires. Periodic twists often lead to a break in such wires, which is why almost nothing remains of their original length over time. In such cases, the block helps out, since only the short end of the wire is enough to connect with it. Terminal splicing is well suited for broken wires laid in the wall, when laying new wiring is difficult, and the remaining length of the wires is clearly not enough for connections in other ways. But such pads can only be plastered when they are installed in a junction box.

Using spring clips

Relatively recently, modified terminals with spring clips have appeared. There are disposable express terminals in which the wires are fixed without the possibility of their further removal, and reusable - with a lever that allows you to get and insert the wires repeatedly. The most popular are the so-called terminal blocks of the German company Wago with paste, specially designed for connecting copper to aluminum. Disposable ones allow you to connect single-core wires with a cross section of 1.5 to 2.5 mm 2, and manufacturers allow their load up to 24 A. But professional electricians still do not recommend supplying current above 10 A to such terminals. Strictly speaking, Wago terminal blocks are best used only in lighting fixtures. With increased load, the contact spring overheats, and the contacts between the conductors are critically violated.

Reusable express terminals are equipped with a pressure lever (usually orange) and can connect wires with any number of cores and a cross section up to 4 mm 2. The maximum current for them is allowed up to 34 A. If the terminals without levers simply snap into place, then for reusable ones you need to lift the lever up to the stop, insert the wire and slowly lower the lever. As a result, the cores will be securely fixed. The cost of such a connection will be much more than the dubious twist, but the work is done quickly and without the use of any additional tools.

Pay attention to the "nuts"

This practical type of connecting (branching) clamps is successfully used on the facades of private houses, when it is necessary to switch from aluminum overhead wiring to noble copper inside the house, since aluminum is prohibited from entering the house by the rules. This is where simple and reliable clamps come in handy in a rounded black polycarbonate case, popularly called nuts for their resemblance.

Inside the case there are two steel dies and an intermediate plate, which we compress with screws after installing the wires. Dissimilar wires here do not conflict on an electrochemical occasion - they are located on different "floors" of the clamp, not touching at all and honestly performing their current-carrying function. To get to the internal parts of the compression, it is necessary to disassemble its body by removing the two retaining rings on the sides. In the dies we will see prudently stamped grooves for conductors of a certain section. It remains only to choose the right size depending on the cross-section of the cores, so that the connection is strong and reliable.

You can also use branch clamps in cases where you do not want to violate the integrity of the cable. After all, it is known that the more connected breaks in the power circuit, the lower its reliability. And if it is a grounding cable, then it cannot be categorically broken at all. Here reliable "nuts" will come to your aid. But in connecting copper and aluminum wires, special care must be taken so that our stay in the house is safe and comfortable.

Any cable product has a conductive core, which is made of copper or aluminum. Since these materials are characterized by excellent return and current conductivity, it is often necessary to connect them during installation and connection. How to connect a copper and aluminum wire without making mistakes will be discussed further.

To deal with all the subtleties of the procedure, you should understand what lies in such a connection. After all, there are different opinions regarding the fact that it is absolutely impossible to connect copper wires with aluminum ones.

Like any other metal, aluminum and copper are oxidized with the participation of oxygen. As a result, an oxide film appears on their surface. And if the copper coating almost does not interfere with the flow of electric current, then the oxide one is a serious barrier to this.

The wire connection of copper and aluminum, in spite of everything, will be the impetus for the interaction of metals. Aluminum is characterized by a higher degree of activity. This means that between the compounds, in the event of moisture, the so-called electrolysis occurs - the transfer of aluminum ions to copper. As a result, the aluminum conductor loses its weight. Shells and voids appear in it, which are also amenable to oxidation and only accelerate electrolysis.

The result is an almost destroyed conductor, which is made of aluminum. As its cross section decreases, the degree of current density increases. In turn, this provokes heating of the metal. There are only two options for the outcome of such a situation: either the aluminum burns out at the connection point, or a fire starts.

Impossible is possible, or how to connect copper and aluminum wire

While some doubt whether it is possible to connect aluminum wires to copper, many successfully do it. Moreover, there are a number of main generally accepted methods, thanks to which it is possible to eliminate contact between materials that act aggressively towards each other. Each of them requires separate attention.

How to connect copper and aluminum using terminal blocks

The terminal block for connecting wires can be equipped with a clamping or bolting mechanism. This design provides connection to two types of materials - aluminum and conductive. They are in contact with each other by means of a steel plate. It is made from a neutral material that does not tend to react with aluminum - often these are brass or tinned copper plates.

The block for wires containing a bolt clamp is characterized by greater reliability and is used in low-voltage power circuits. Often such a clamp is performed using a "nut". It is a small junction box, which is made of dielectric materials. The device got its name due to its shape. Inside it is a block of metal plates, through which contact is provided between copper and aluminum wires.

Each of the above methods is a detachable connection. This means that if necessary, you can repeatedly disconnect and connect them.

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

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

Welding.
Crimping.
Soldering.
Connection using .

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

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

It is unable to conduct electricity through itself. In addition, the oxide film has a rather high melting point - in the region of 2000 degrees. This figure is much higher than the melting point of aluminum itself.

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

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

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

Twisting

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

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

At first, the insulation is removed from the wires approximately 4-5 cm on each side. It is most convenient here to use a special tool designed specifically for this purpose.
Now the contacts should be degreased. To do this, they will have to be wiped with a cloth previously moistened with acetone.
sandpaper remove the oxide film from the surface of the metal, that is, they clean it until a metallic sheen is obtained.
Wires cross each other, after which one of the cores is twisted as tightly as possible onto the other with the help of pliers.
Second wire in the same way it is wound on the first one.
The twist should now be insulated with insulating tape. Professional electricians also recommend using a special heat shrink tube or cambric. With it, you can qualitatively protect the bare area from the negative effects of the external environment.

In principle, the technology is quite simple. It is only necessary to remember that the cores need to be bared by at least 4-5 cm, and the twisting should not be done manually, but only with the help of pliers, so that the wires fit as close to each other as possible.

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

Threaded connection

This type of connection can be very reliable if done correctly. It should be noted that aluminum has the highest linear expansion, and therefore a gap appears between the connected wires over time, which worsens their contact with each other. To prevent a short circuit, you need to tighten these screws from time to time.

To get rid of this need, install special washers with cuts or grovers. They choose the resulting gaps and several times increase the reliability of the connection.

On the screw, the wires will need to be wound so that the area of \u200b\u200bcontact with the contact pad is much higher. Professional electricians often do this: they flatten this ring on an anvil to increase the contact area.

The technology for making a high-quality threaded connection of wires begins with the removal of insulation from them at a distance equal to 4 screw diameters. Cleaned areas are degreased.

Then you need to bend their tips so that rings form.

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

Spring washer.
Standard puck.
Ring of the first wire.
Another standard washer.
Ring of the second wire.
Screw.

This whole system is tightened until the spring washer is in a straightened state. In principle, if both wires are made of aluminum, then a standard washer can not be laid between them.

We use terminal blocks

If aluminum wires have a slight current load, then they can be interconnected using terminal blocks. Despite the fact that the appearance of such products may vary greatly, the principle of their work is the same.

The body of the pads is made of plastic or carbolite. It contains tubes with thick walls made of brass. There are threaded holes on the sides. Connected wires are inserted into opposite ends, which are fixed with screws. It should be noted that it is allowed to insert as many wires into one brass tube as will fit there.

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

Permanent connection

If in the future it is not planned to disassemble the connection of wires, then the so-called one-piece methods can be used. These methods are among the most reliable. It is desirable to use them, first of all, in hard-to-reach places.

One of the easiest methods of permanent connections is crimping. To do this, an aluminum tube of a suitable diameter is taken, the wires are twisted together, inserted into this tube and clamped with press tongs. It is best here that the conductors enter as tightly as possible.

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

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

To obtain a high-quality one-piece connection, you need to have special pliers that will not bite, but only squeeze. If they are not available, then standard pliers are quite suitable.

Soldering and welding

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

To prevent the occurrence of such a defect, you need to follow a certain sequence of actions:

Connected sections of wires treated with a special flux, which removes the oxide film from the surface.
Solder is handled as carefully as possible so that it has the largest area of \u200b\u200bcontact with the wires.
When the connection area cools down, it is desirable to process it with sandpaper to remove sharp edges that can damage the insulating layer.
Wires must be insulated.

Soldering requires certain skills.

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

He has to be isolated.
The method itself is rather complicated., especially if you have to solder wires under the ceiling, standing on a stepladder.
If an error was made in the course of work, then fixing it will be quite problematic.
It takes a lot of time to work.

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

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

After the welding process is completed, the twists are passed with a special solvent and varnished. The result is a quality connection that can last for a long period of time, as this method allows you to prevent the occurrence of overheating. Accordingly, such an area will need to be isolated.

Alternatives

flat spring clamp

The wires can be connected to each other with a rivet. In principle, this technology is similar to screw technology, only here a rivet is taken instead of a screw. The end result is a non-separable connection.

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

Also, there is a special flat-spring clamp. Such products are disposable and reusable, when the wire can be both inserted and removed. However, it should be remembered that such clamps are made of plastic, so it is undesirable to use them for currents above 10 A.

Working with them is very simple: the wires are stripped and inserted into the clamp until it clicks. It is impossible to pull them out without using a special lever. It is also desirable to isolate this section of the wire.

Connection Features

Aluminum wires are best placed in special ones, to which they must fit in corrugated sleeves. This is especially important when laying outdoors or in the case of wiring in a damp room such as a bathroom.

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

Otherwise, a short circuit cannot be avoided. It is very convenient in this case to use the technology of welding wires, since the subsequent use of a special varnish makes it possible to exclude the effect of water on the junction, and the insulating layer additionally protects against electric shock.

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

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Connection of aluminum and copper wires. Connection of aluminum and copper wires to each other Adapters for wires from aluminum to copper

Reasons for incompatibility

Bolted connection

Clamp "Nut"

Terminal block

Self-clamping terminals

Twisted connection

Twisted connection

Threaded wire connection

Terminal block connection

Connection using terminal blocks

Method of connecting copper and aluminum wire

Electrochemical corrosion

Overview of connection methods

Bolted connection

Terminals

Wago terminal blocks

Rivets

soldering iron

Connection quality

stranded wires

Sleeves

Twisting

How to connect copper and aluminum wire correctly?

Danger of bad wiring

Methods for joining copper to aluminum

Wire twisting

Threaded method

Terminal method

One-piece method

How to connect aluminum wires - methods for connecting aluminum and copper wire

What is their feature

screw

spring

Twisting

Permanent connection

Welding

Soldering

Crimping

aluminum and copper wire

Video

How to connect copper and aluminum wire

Reasons for incompatibility

Bolted connection

Clamp "Nut"

Terminal block

Self-clamping terminals

Twisted connection

How to connect aluminum and copper wire

Why You Can't Just Twist Aluminum and Copper Wires

Connection with threaded devices

Rivet splicing

Sockets and clamps with terminals

External connections

Summary

Twisting is not the best method

The easy way with screws

When there is a rivet on hand

Connect with terminal block

Using spring clips

Pay attention to the "nuts"

Impossible is possible, or how to connect copper and aluminum wire

How to connect copper and aluminum using terminal blocks

Twisting

Threaded connection

We use terminal blocks

Permanent connection

Soldering and welding

Alternatives

Connection Features

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