How to properly connect aluminum to copper

How to connect copper and aluminum wire: TOP methods

There are still quite a few electrical networks with aluminum wires in the secondary housing stock. And solving the problem of how to connect copper and aluminum wire remains vital when connecting electrical products. The safety of splicing with simple twisting, it is not for nothing that it is not recommended by the PUE, is quite precarious. In conditions without excessive humidity, the contact is benign. As soon as moisture appears, the connections begin to heat up and collapse.

What happens when dissimilar metals join

Each conductor has its own electrochemical potential. This feature is successfully used in the manufacture of batteries and accumulators. But when two metals come into contact under conditions of humidity and stress, they begin to actively deteriorate. The results of this process are: fire of insulation, breakage of the electrical circuit.

Eliminating such a defect in hidden wiring will require time to detect, open and restore the surface of the walls. This happens when the splicing was performed by simply twisting two dissimilar cores. If connected correctly, the electrical contact will be reliable and will last a long time.

Methods for properly connecting aluminum and copper electrical conductors

When creating temporary electrical circuits, twisting of copper and aluminum wires occurs quite often. This is the fastest way to splice power lines in the absence of auxiliary materials. For short-term use, although not recommended, this option is possible. When laying a major power line, the following types of connections are used:

twisting with tinning of a copper core;

• threaded
• block
• one-piece
• spring clamps (Wago)

All these methods make it possible to reliably splice a copper core with an aluminum one, followed by long-term, safe operation of the electrical network.

Tinned copper wire

The pre-cleaned copper core is coated with tin solder (tinning) using a soldering iron. After this procedure, you can connect both wires by twisting. The length of the ends cleared of insulation should be 4-5cm.

Simple twisting is done by twisting the wires onto each other. After this, the connection is insulated with tape, cambric or heat shrink tubing. The latter option significantly enhances the reliability of contact.

Threaded connection

It is possible to reliably connect copper and aluminum electrical conductors using nuts, washers, and screws. The assembled contact is easy to disassemble and is of high quality. Provides a good connection for the entire period of operation of the electrical network. The number of wires you can connect limits the size of the screw.

The main rule is to avoid direct contact between aluminum and copper. The conductors are exposed to a length four times the diameter of the screw. They clean off oxides and form rings into which the screw will be inserted. In a certain sequence they wear:

• spring washer
• an ordinary washer
• copper wire ring
• puck
• aluminum core ring
• a simple washer
• nut

By tightening the screw, the entire package is tightened until the spring washer straightens. In stranded copper wires, a ring is first tinned to form a solid segment.

Terminal block connection

The most common option for splicing aluminum and copper conductors. In terms of reliability, it is inferior to the threaded one, but allows you to quickly complete the process in any combination. There is no need to prepare connecting areas or carry out insulation.

Structurally, the pads eliminate the presence of exposed wires and accidental contact with them. To connect, the ends of the cores are stripped to 0.5 cm. They are inserted into the holes in the block and clamped with screws. This option is the fastest and quite reliable. It is necessary to take into account that when wiring is hidden, the terminal blocks must be placed in the junction box.

Pads with clamps

New items on the electrical market, “Wago” clamps, have recently appeared in the arsenal of electricians. They are produced by a German manufacturer in two versions: disposable and reusable. Single-use designs allow the product to be used only once. Once the wire is inserted into the device, it is no longer possible to remove it back.

Reusable designs have a lever that allows the removal and insertion of conductors. The device is reliable and convenient, but has the highest cost of use. An unpleasant feature: the presence of many fakes on the market. As a result, connections may be unreliable, since the quality of non-originals leaves much to be desired.

Permanent connections

They have all the advantages of the threaded method. Disadvantage: there is no possibility of disassembling the structure. The connection is made by applying a special tool to the rivet. The preparation procedure is similar to the threaded connection diagram.

The prepared structure is placed in the tool, then it is compressed until it clicks. After this, the connection is ready for use. The method is convenient for splicing damaged sections of hidden aluminum wiring with copper wire inserts and in other cases. A prerequisite is careful isolation of bare areas.

Methods for connecting copper and aluminum wires (video)

Source: https://zbbr.ru/kak-soedinit-mednyj-i-alyuminievyj-provod/

Connecting aluminum and copper wires: how to better and more competently connect products made of aluminum and copper - VashElektrik

In apartments of old buildings, the electrical wiring is often made of aluminum wires connected to each other by twisting.

When connecting lamps to aluminum wiring, installing additional sockets and other electrical equipment, it is necessary to take into account that with increased humidity, the contact resistance between aluminum and copper wires increases over time.

This leads to heating of the junction and destruction of the contact. To reliably connect copper and aluminum wires to each other, you must follow simple rules, which will be discussed.

Electrochemical corrosion of joined metals

There is an opinion that it is unacceptable to connect aluminum and copper wires directly together and this is indeed a scientifically proven fact. Is it possible to connect a copper wire to a galvanized terminal? Of course, you cannot immediately give an answer, but in a minute you will be able to navigate this issue no worse than an experienced chemist.

What happens when two different current conductors come into contact? If there is no moisture, the connection will always be reliable. But there is always water vapor in the atmospheric air, which is the culprit for the destruction of contacts. Each current conductor has a certain electrochemical potential. This property is widely used by humans, for example, batteries and accumulators are created.

But if water gets between the metals, it forms a short-circuited galvanic cell, current begins to flow, and just as one of the electrodes is destroyed in the galvanic bath, so one of the metals in the connection is destroyed. The electrochemical potential of each conductive material is known, and knowing the value, you can accurately determine which materials can be connected to each other.

Table of electrochemical potentials (mV)
arising between connected conductors

According to the requirements of the standard, mechanical connection between materials is allowed, the electrochemical potential (voltage) between them does not exceed 0.6 mV. As can be seen from the table, the reliability of contact when connecting copper to stainless steel (potential 0.1 mV) will be much higher than with silver (0.25 mV) or gold (0.4 mV)!

And if a copper wire is coated with tin-lead solder, then you can safely connect it with aluminum in any mechanical way! After all, then the electrochemical potential, as can be seen from the table, will be only 0.4 mV.

Connecting copper wires to existing wiring made of aluminum wires is not as difficult as it seems at first glance. The main thing is to follow the technology.

Twist connection

Twisting, although currently prohibited by the PUE rules, is one of the most common methods of connecting wires in everyday life, due to its simplicity and does not require additional costs. But when connecting dissimilar metals, twisting is also the least reliable method of connecting conductors.

When the ambient temperature fluctuates, due to the linear expansion of metals, a gap forms between the twisted wires, the contact resistance increases, heat begins to be generated, the wires oxidize, and ultimately the contact between the conductors is completely broken. Of course, this happens after more than one year, but, nevertheless, if reliable long-term operation of the electrical wiring is planned, then it is better to replace the twisted wire connection with a more reliable one, for example, a threaded one or using terminal blocks.

But if there is a need to twist the wires, then the twisting must be done in such a way that the conductors wrap around each other, and not one wraps around the other.

The photo on the left shows twisting, which is unacceptable, since it will not ensure sufficient mechanical strength of the connection.

Twisting a copper conductor and an aluminum one without taking measures for additional sealing is not permissible. The twist can be sealed with any waterproof protective varnish.

The most reliable connection between copper and aluminum conductors will be achieved if the copper wire is first tinned with solder. In the right photo, the copper and aluminum wires are twisted correctly.

Wires of different diameters can be connected, stranded wire with single-core wire. Only the stranded wire must first be tinned with solder, thus making it single-core.

There must be at least three turns in the twist for a thick wire and at least five for a thin wire with a diameter of less than 1 mm.

Threaded connection
of aluminum wires with copper

Connecting wires, when done correctly, using screws and nuts is the most reliable and is capable of ensuring proper contact throughout the entire service life of the electrical wiring and connected electrical appliances.

Easily disassembled and allows you to connect any number of conductors, limited only by the length of the screw. Using a threaded connection, you can successfully connect wires in any combination, aluminum and copper, thin and thick, stranded and single-core.

The main thing is to avoid direct contact between copper and aluminum wires and install spring washers.

In order to make a threaded connection, it is necessary to remove the insulation from the conductors to a length equal to four screw diameters; if the wires are oxidized, then clean the metal until it shines and form rings.

Next, a spring washer, a simple washer, a ring of one conductor, a simple washer, a ring of another conductor, a washer and, finally, a nut are put on the screw, screwing the screw into which the entire package is tightened until the spring washer is straightened.

For conductors with a core diameter of up to 2 mm, an M4 screw is sufficient. The connection is ready. If the conductors are made of the same metal or when connecting an aluminum wire to a copper wire whose end is tinned, then there is no need to place a washer between the rings of the conductors. If the copper wire is stranded, then it must first be tinned with solder.

Connecting aluminum wires to copper
terminal block

Currently, the method of connecting wires using a terminal block has become widespread. Of course, this type of wire connection is inferior in reliability to a connection using a screw and nut, but it has a number of advantages.

Allows you to reliably and quickly connect aluminum and copper wires to each other in any combination; there is no need to form rings at the ends of the wires, and there is no need to insulate the connection, since the design of the terminal block prevents the bare sections of the wires from accidentally touching each other.

To connect a wire to the terminal block, just strip its end of insulation to a length of 5 mm, insert it into the hole and tighten it with a screw. The screw must be tightened with considerable force, this is especially important when connecting aluminum wires.

The terminal block is indispensable when connecting the chandelier to short aluminum wires coming out of the ceiling. From repeated twisting, aluminum wires break off and become short.

Even if the aluminum conductor is only one centimeter long, you can reliably connect the chandelier using the terminal block.

A terminal block is very convenient for connecting aluminum and copper wires broken in the wall, since the length of broken wires for connection by other methods is insufficient. But hiding the terminal block under the plaster without placing it in a distribution box is not permissible.

Currently, terminal blocks with flat spring clamps Wago (Wago) from a German manufacturer are widely used. Wago terminal blocks come in two designs: disposable, when the wire is inserted without the possibility of removal, and reusable, with a lever that allows you to repeatedly insert and remove wires.

The photo shows a Wago disposable terminal block. They are designed for connecting any types of single-core wires, including copper and aluminum wires with a cross-section from 1.5 to 2.5 mm2. The block is designed to connect electrical wiring in junction and distribution boxes with a current of up to 24 A, but I doubt it. I think it’s not worth loading the Wago terminals with a current of more than 5 A.

Wago spring terminal blocks are very convenient for connecting chandeliers, connecting wires in junction and distribution boxes. It is enough just to forcefully insert the wire into the hole of the block, and it will be securely fixed.

In order to remove the wire from the block, considerable force will be required. After removing the wires, deformation of the spring contact may occur and a reliable connection of the wires when reconnected with this terminal is not guaranteed.

This is a big disadvantage of a disposable terminal block.

A more convenient Wago terminal block is reusable and has an orange lever. Such terminal blocks allow you to connect and, if necessary, disconnect any electrical wires, single-core, stranded, aluminum in any combination with a cross-section from 0.08 to 4.0 mm2. Rated for current up to 34 A.

It is enough to remove 10 mm of insulation from the wire, lift the orange lever up, insert the wire into the terminal and return the lever to its original position. The wire will be securely fixed in the terminal block.

The Wago terminal block is a modern tool-free way to connect wires quickly and reliably, but is more expensive than traditional connection methods.

Permanent connection
of aluminum wires with copper

A permanent connection of wires has all the advantages of a threaded connection, with the exception of the possibility of disassembling and reassembling the connection without destroying the rivet and the need for a special tool for making the rivet - a riveter.

Today, rivets are widely used for permanently connecting thin-walled structural parts when creating partitions and interiors in any premises.

Speed, strength, low price and scope for riveting operations are the main advantages of this type of permanent connection.

The operating principle of the riveter is simple: retracting and cutting a steel rod threaded through a tubular aluminum rivet with a head. The rod has a thickening and when it is pulled into the rivet tube, it expands it. Rivets come in different lengths and diameters, so you can choose any one.

In order to connect the conductors with a rivet, you need to prepare them in the same way as for a threaded connection. The diameters of the rings should be slightly larger than the diameter of the rivet. The optimal rivet diameter is 4 mm.

First, an aluminum conductor is placed on the rivet, then a spring washer, then a copper one and a flat washer. Insert a steel rod into the rivet gun and squeeze its handles until it clicks (this cuts off the excess steel rod).

The connection is ready.

The reliability of threaded and non-detachable rivet connections is quite high. This connection method can be successfully used to splice, for example, aluminum conductors damaged during repair work in a wall with an additional insert. You just need to take care of good insulation of the exposed areas of the connections.

You can find other types and methods of connecting wires on the page “How to properly connect electrical wires.”

Source: https://agk-sport.ru/osveshhenie/soedinenie-alyuminievogo-i-mednogo-provoda-kak-luchshe-i-gramotnee-soedinyat-izdeliya-iz-alyuminiya-i-medi.html

Is it possible to connect aluminum wires with copper wires, how to do it correctly

When carrying out various electrical installation work, beginners often have a question: is it possible to connect aluminum wires with copper wires?
If so, what should you consider? Or is it better not to?.. Well, we can dwell in more detail on these and other related issues.

And yet, is it possible to connect aluminum wires with copper

Generally speaking, in case of emergency, this can still be done. But, as they say, be careful.

Twisting is a common option for connecting wires when installing electrical wiring, but when connecting wires made of dissimilar metals, this option is completely unacceptable.

In the old days, many self-taught electricians got by by simply twisting copper and aluminum wires together, then wrapping the whole thing in blue electrical tape - and nothing, it worked. For the time being, true. It was in the most literal sense - Russian roulette. After all, it was impossible to say in advance exactly when it would “explode.”

It could have blown through, but such a twist could have led to huge troubles and even cost the lives of the whole family. In order to understand what, strictly speaking, the danger is, you can recall the basic concepts from the school course in physics and chemistry. First of all, aluminum and copper have different characteristics in terms of resistivity.

Moreover, the lower the resistance of the conductor, according to Ohm’s law, the greater the current strength at a constant voltage. Since the voltage in the household network usually remains unchanged - it is the usual 220 volts - the electric current begins to gain strength. If it flows from a conductor of greater resistance to a conductor with less, then a jump in current strength begins to be observed in the latter.

As a result, the conductor heats up with less resistance - and a fire is almost guaranteed. The risk increases significantly during regular voltage surges - which, it’s no secret, is common in domestic power grids.

However, the difference in resistivity can be leveled out if conductors of different cross-sections are used.

After all, the larger the cross-sectional area of ​​the conductor, the lower the resistance, and vice versa. Therefore, a wire made of a material with lower resistance should simply be thicker - and the problem is solved?

Copper and aluminum cannot be combined together, because... The presence of humidity and water vapor in the air is one of the factors that destroys contacts.

Not resolved at all. After all, the second danger is that conductors made of different materials are subject to so-called electrochemical corrosion over time in an oxygen environment. The situation is aggravated by the direct connection of aluminum and copper wire. As a result, a galvanic couple is formed, which will gradually destroy the conductor.

To prevent this from happening, you need to ensure that the environment is completely dry. However, in practice this is not possible. After all, there is always moisture in the air. Especially when it comes to a bathroom or shower.

Finally, even the strongest twist will come apart over time if dissimilar materials are used.

Indeed, due to the difference in resistance, there will also be a difference in temperature for one and the other conductor. They will expand at different speeds, which, when the current consumer is periodically turned on and off, will be tantamount to pulling the twist back and forth.

Of course, not in a couple of hours or even in a couple of days, but sooner or later there will be a breakdown in contact between the conductors - and sparking wiring in this case is far from the biggest nuisance.

Note! Direct twisting of wires made of copper and aluminum is today strictly prohibited by all known rules. A conscientious master will never allow himself anything like this.

However, this does not mean that there are no ways to solve the problem of connecting copper and aluminum wires to each other.

How to connect dissimilar conductors using the threaded method

Connecting copper and aluminum wires with a screw and nuts is the most reliable contact, capable of ensuring conductivity for the entire life of the electrical wiring.

One of the possible options, which allows for a high-quality connection of not only copper and aluminum wires, but also any dissimilar conductors in general, is the threaded connection method. It is done using a screw and nuts.

Moreover, the number of conductors is limited in practice only by the length of the screw itself onto which the wires are attached. In this way, it will be possible to combine almost all known types of conductors - of different thicknesses and made of different materials, with different numbers of cores, etc.

To successfully complete this type of connection, you will need:

• Remove the insulating layer from the wires to a length that will be equal to four diameters of the screw on which the bait is applied;
• Next, you should make sure that the cores themselves have not undergone oxidation. Otherwise, you need to clean them to a metallic shine;
• Now you need to form rings from the bare metal part of the conductor;
• At the next stage of work, a spring washer is put on the screw, then a regular washer - and a ring from one conductor. Again, a simple washer is placed on it, and then you can put on a ring from another conductor;
• A fastening nut is screwed onto the resulting “sandwich”. It must be screwed until the spring washer straightens.

The basic rule is to prevent direct contact between aluminum and copper, and to install spring washers under the nuts.

As practice shows, for a standard wire with a diameter of 2 millimeters it will be enough to take an M4 screw.
If stranded copper wire is used, it must be properly tinned with solder before starting work.

How to connect dissimilar wires using terminal blocks

Although the method described above ensures reliability if implemented correctly, today they are increasingly resorting to another method - through a connection using the so-called terminal block.

It is worth noting that, although in terms of reliability of fastening the terminal block is inferior to a threaded connection, the implementation of fastening in this way is more convenient and faster. There is no need to form any rings, carry out final insulation, etc. After all, the entire design of such a block assumes that the wires are in an isolated position.

In order to connect the wires using a terminal block, you will need to strip their ends of insulating material to a length of about 5 millimeters. Then the bare end of the wire is simply inserted into the hole on the block - and clamped using the supplied screw. In this case, you need to screw with noticeable force.

This is especially true for aluminum wires. Indeed, due to the expansion of the material due to heating of the wire, the connection may weaken over time.

A common option is to connect wires made of different metals using a block.

• For example, if you have to connect a chandelier with a shortened aluminum wire. As a result of repeated twisting, aluminum wires may break off - and then only a block will help;
• Or if you have to connect copper and aluminum wires broken inside the walls. After all, the length of the broken wires is not sufficient to form not only a twist, but also to make a threaded connection. In this case, the lack of length will be compensated by the terminal block.

Connecting the block terminal with a Wago flat spring clamp

Particularly worth noting is the so-called Wago spring clamp, which is used in terminal blocks of conventional German production. Moreover, such blocks can be in reusable and disposable versions. In the first case, it will be possible to open the lock many times and change the wires if necessary, but in the second case, the wire is placed in the block only once, and it is impossible to remove it again.

Wago terminal blocks are designed for connection with a current strength of up to 24 amperes, as the manufacturer assures. But practice shows that it is better not to risk a current of more than 5 amperes.

If you use a Wago lock, insert the stripped end of the wire 10 mm into the hole in the block - and it will be fixed inside.

In order to remove the wire, you will need to apply quite a lot of force.

Terminal blocks from the world leader WAGO have long been known as a reliable device for quick installation of electrical wiring.

Permanent connection of wires using the rivet method

This method will require the purchase of a special rivet machine. In this case, the wires are prepared in exactly the same way as for a threaded type of connection. As for the diameter of the rings, it should be slightly larger than the diameter of the rivet itself.

Typically the diameter of each rivet is 4mm. First, an aluminum conductor is put on it, then a spring washer, then a copper wire should be put on - and a flat washer on it.

Now the rivet rod is inserted into the machine - and the handle is clamped until a characteristic click is heard, which indicates that the connection is ready for use.

Manual riveter is a professional hand tool for installing threaded (nut) rivets and screw rivets.

What do experts recommend?

Evgeniy Valerievich Sukhorukov, electrician: If you use removable type threaded screw connections, you will need to monitor them at least once a year for loosening.
Elena O., sales consultant: It’s not worth purchasing a terminal block with a margin of wire thickness. If you have doubts about whether the wire will fit into the hole, it is better to cut a sample and bring it with you to the store.

Results

Source: http://79w.ru/elektrosnabzhenie/provodka/mozhno-li-soedinyat-alyuminievye-provoda-s-mednymi-kak-pravilno-eto-delat

How to properly connect copper and aluminum wire

Many people have probably encountered such a problem when twisting wires begins to spark and knock out the machines. Naturally, this is unpleasant and poses a major security risk. When using wires made of various materials in your home electrical network, you should clearly know how to connect copper and aluminum wires and do it correctly. After all, with direct contact, copper and aluminum oxidize, compromising the quality and integrity of the twist.

Any conductor (copper, aluminum, steel and others) has a certain electrochemical potential. When moisture in the air and oxygen interact, 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 various conductors. Knowing them, you can choose the right materials that are well connected to each other.

Table of electrochemical potentials (mV) arising between connected conductors.

Metal	Copper and its alloys	Lead-tin solder	Aluminum	Duralumin	Steel	Stainless steel steel	Zinc coating	Chrome coating	Silver	Carbon (graphite)	Gold Platinum
Copper and 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
Soft 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 coating	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 them does not exceed 0.6 mV. Therefore, 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 select some kind of spacer between these materials, which optimizes the tension in the bond.

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

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

Twisted connection

Twisting is the most common but less reliable method of connecting wires.

Many people resort to this method due to its simplicity and lack of appropriate qualifications. But you need to know that when the ambient temperature fluctuates, due to the linear expansion of metals, the following occurs:

• A gap is formed between the twisted wires.
• The contact resistance of the conductors increases.
• Heat begins to be released.
• The wires oxidize and the contact is completely broken over time.

In order to obtain a more reliable contact, it is better to avoid using twisting. But, if you still choose this connection method, you should adhere to the following rules:

• The different conductors should wrap around each other well
• Measures are required to additionally seal 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 connection of wires

The next acceptable type of connection is threaded using screws and nuts. It is the most reliable and is capable of providing good contact throughout the entire service life of the wiring.

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

• From different metals (for example, copper and aluminum).
• Various thicknesses (core diameter).
• Stranded and single-core.

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

Let's consider the stages of creating a threaded connection:

1. It is necessary to remove from the wire an insulating layer long enough to crimp the thread of the bolt.
2. Oxidized areas must be cleaned and degreased. And when using a stranded conductor, it must first be tinned.
3. Then a washer - a copper core (as an example) - a washer - an aluminum core - a washer is installed on the screw one by one. The washers must be steel.
4. Finally, the entire structure is secured 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 while screwing in, the connection will be optimally secured.

Terminal block connection

Connecting wires using a terminal block is inferior in reliability to connecting using a screw and 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 using this method, the ends of the conductors are cleared of insulation to a length of 4 - 8 mm (depending on the diameter), inserted into the hole and clamped with the supplied screws.

Recommendations for use:

1. Under no circumstances should terminal blocks be used in critical and powerful areas. Putting it into the plaster under the finishing layer is also not the best option.
2. Suitable for use in visible areas (in junction boxes) and in conjunction with low-power devices (lamps, chandeliers).
3. When fixing the cores, the screw must be firmly clamped. This will prevent the contacts from loosening.
4. When using conductors made of various metals, keep in mind that an excessively exposed core may have contact with a core threaded on the other side. In this case, partial oxidation and weakening of the bond will occur.

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

Connection using terminal blocks

Connection using WAGO terminal blocks

The most common type of this connection is terminal blocks with spring clamps from the German manufacturer Wago. They are designed for connecting any types of single-core wires (tinned stranded) with a cross-section from 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. 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 worth taking into account the load on the lines of the home electrical network and selecting 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 8 - 10 mm of insulation from the conductor. and insert it into the terminal.

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

Source: https://poweredhouse.ru/kak-soedinit-mednyj-i-alyuminievyj-provod/

How best to connect aluminum and copper cable: methods

• Types of cable connections
• What is the best way to connect aluminum cable cores?

How best to connect an aluminum cable: methods

When connecting wires, you need to understand how to do it correctly. Otherwise, the wires may quickly burn out or there will be poor contact, which will lead to the electrical wiring starting to get very hot.

This is especially true for connecting aluminum wires, which cannot be soldered with tin and rosin (mmasvarka.ru). And, of course, you probably know that twisting copper and aluminum wires is not recommended.

Firstly, such a connection will oxidize, which will lead to loss of contact, and secondly, it will become very hot, which can lead to the wire burning out.

Types of cable connections

You can connect aluminum wires to each other in different ways, namely:

• Twisting method. However, this method of connecting aluminum wires has one significant drawback. Aluminum wire is very sensitive to bends, etc. Therefore, it can break in places where it is twisted;
• For bolt and nuts. A more reliable method of connecting aluminum wires than the one described above. To do this, take a bolt and several nuts with washers, between which one and the other end of the wires being connected is clamped. In this case, the connection is quite reliable and durable. Its only disadvantage is that it is bulky, and often open, without any insulation;
• Pads. Universal devices for connecting wires, and those can be made of dissimilar metals;
• By means of a sleeve. You can connect aluminum wires using a small tube for this purpose, which is crimped after two or more wires have been laid in it. Before this, it is recommended to twist the aluminum wires together and then crimp them using a sleeve.

Let's take a closer look at how exactly aluminum cables are connected using all of the above methods.

What is the best way to connect aluminum cable cores?

Twisting aluminum wires - with proper winding, this connection method will last at least 50 years. Twisting of wires can be different, for example, as in the pictures. The second connection method is certainly much better and more reliable.

Bolted connection - take a long bolt and wrap one end of an aluminum wire around it, closer to the head. Then a washer is put on the bolt, and the end of the other wire is wound behind it. After this, everything is tightened with one or two washers. Bolts, washers and nuts are best used to connect wires made of dissimilar metals, such as aluminum and copper.

Terminals and blocks are an equally popular way to connect aluminum wires. This method is fast and reliable, as well as the ability to connect copper and aluminum wires. Today there is a wide variety of terminal blocks, for example, Wago, and simpler ones in design.

Sleeve connection - with this method, two wires are twisted together and then crimped using a cable sleeve. For greater reliability, the sleeve is crimped not with pliers, but with press tongs specially designed for this purpose.

To make a sleeve to connect two wires, you can use a copper tube to connect the air conditioner. The sleeve must have a length of at least 5-7 cm, and its diameter depends on what cross-section of the cable will need to be connected (crimped).

Source: https://mmasvarka.ru/kak-luchshe-soedinit-alyuminievyj-kabel.html

Connecting copper and aluminum wires: how to do it correctly?

Directly connecting a copper and aluminum conductor creates an unacceptable galvanic couple, in which oxidation processes occur under the influence of moisture and air. Because of this, the contact begins to burn and can lead to the wire burning out or even a fire. How to connect the wires correctly so that the connection lasts a long time? Let's discuss the best ways.

Bolted connection

This is one of the most reliable ways to connect copper and aluminum conductors. It will require a steel bolt with a nut and several washers (one more than the wires). The connection is made as follows:

• We put the first washer on the bolt.
• We twist the conductor core into a ring and put it on the bolt so that the ring is wrapped in the direction of tightening the nut.
• We place a steel washer and put the core of another conductor on it.
• Place the third washer, the engraver on top of it, and screw on the nut (as in the illustration).

The advantage of a bolted connection is that several conductors can be attached at once. Also, the design is collapsible, so you can always remove the connection or, on the contrary, add a wire as necessary. However, the connection itself is quite large, and it is not easy to isolate it. Also, over time, the contact needs to be tightened, so it should be used only in places that provide easy access to the connections (you cannot sew it into the wall).

Nuts

The nut is a small plastic box, inside of which there are three steel plates connected to each other with screws. Copper and aluminum wires are laid between the plates and fastened tightly with screws.

Moreover, you can use both stranded and single-wire conductors. Most often, nuts are used to connect the aluminum input wire of the SIP and the copper wire leaving the house.

Like a bolted connection, nuts can be disassembled, so they are classified as reusable connections.

However, due to their large dimensions and awkward shape, nuts cannot be used in junction boxes. Also, they cannot be “sewn” into the wall. On average, the price of such a branch cable clamp ranges from 25 to 80 rubles, depending on the cross-section of the conductors used and the manufacturer.

WAGO terminal blocks

WAGO clamps consist of a self-clamping metal plate treated with anti-oxidation paste and a dielectric housing. Aluminum and copper wires are inserted into adjacent holes and pressed against one plate. Thus, the materials do not come into contact with each other and do not oxidize.

WAGO clamps are used mainly for groups of lighting devices, since with a high current load the plate can often burn out and the clamp itself can melt. Please note that the maximum cross-section of wires for WAGO clamps is 2.5 mm2, so we do not recommend installing a core thicker than this.

The advantage of WAGO terminal blocks is the speed of installation and compact dimensions, thanks to which the connections can be easily installed in the junction box. However, WAGO is quite expensive in terms of cost, and with a large number of connections it will cost its owner a pretty penny.

Twisting followed by soldering

The usual twisting of aluminum and copper wires is not allowed, as it will oxidize and collapse. However, if you apply soldering in compliance with certain technological processes, then everything will be fine. To solder copper and aluminum you should do the following:

• We tin the copper core with lead-tin solder.
• We take a solution of vitriol, a Krona battery and a piece of copper wire (not the one we will solder).
• We apply copper sulfate to the aluminum conductor and then fasten it to the negative side of the battery.
• We wind a copper wire around the plus of the battery, and lower its other end into a glass of vitriol.
• After a while, the aluminum core will be covered with copper, which will allow it to be properly soldered to the copper conductor.
• After soldering, insulate the connection with electrical tape or heat shrink.

The method may seem somewhat complicated at first glance, but the quality of the connection will be at the same level. Note that the wires connected in this way can be hidden in the wall, since the contact in them will not weaken and they will not need to be tightened.

Screw terminal blocks

Screw terminal blocks allow you to connect two wires without direct contact between them. Two wires are inserted into the terminal block and pressed with screws. The disadvantage of this compression is the need to regularly tighten the screws, so they need to be mounted in places with easy access. They are also designed exclusively for lighting groups (although the manufacturer claims that they are also suitable for sockets), since they can withstand a low current load.

The main advantage of screw terminal blocks is their low cost. For example, the DKC 43112FV terminal block costs less than one hundred rubles.

Crimping

Crimping is the most reliable and high-quality connection of two conductors consisting of different metals. There are special copper-aluminum sleeves GAM, into which two wires are inserted and crimped using a press. However, it is worth noting that they are designed for wire cross-sections starting from 16 mm2, and apartments often use conductors from 1.5 to 4 mm2. Therefore, we will connect with a regular aluminum sleeve. Crimping of cores is performed as follows:

• We tin the stripped ends of the copper conductor with lead-tin solder. This will avoid contact between the cores.
• We remove the oxide film from the aluminum core.
• We insert the cores into the sleeve from different ends and crimp them.
• We insulate the sleeve with electrical tape or heat shrink.

Please note that with strong crimping inside the sleeve, the solder layer on the copper core may be destroyed, so choose the size of the sleeve and the matrix with which you will crimp the cable correctly.

The advantage of this method is that you can sew such a compression under the plaster without fear that the connection will burn. However, to complete the process you will need a press, which costs a lot of money.

Perhaps you have your own original ideas and life hacks for connecting copper and aluminum wires (the main thing is that the methods do not contradict the PUE) - share them in the comments!

Source: https://ichip.ru/sovety/remont/soedinyaem-mednyy-i-alyuminievyy-provoda-kak-pravilno-652602

How to properly connect copper and aluminum wires?

› Electrical wiring › Wires and cables ›

25.09.2018

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

What problems may arise when joining aluminum and copper?

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

1. Reduced electrical conductivity. Aluminum is an active metal; under normal conditions it is covered with an oxide film that has low conductive qualities. Copper does not have this property.
2. Loosening contacts. Due to the formation of plaque, contacts become worse. No such film is formed on copper conductors, therefore the metals are considered electrochemically incompatible.
3. Fire hazard. When wondering how to connect an aluminum wire to a copper wire, they remember that electrical contact occurs between the oxide deposits formed on the wires. Over time, the metals begin to heat up, which leads to fire.
4. Electrolysis. If the system is operated in conditions of high humidity, the connection begins to deteriorate, becoming a source of fire. Corrosion primarily affects the aluminum parts of the wiring. With regular heating and cooling, cracks appear in the insulating braid, and the connection is covered with an oxide or salt layer, which accelerates destruction.
5. Formation of conductive soot. In this case, contact is broken and a fire starts in the house. When operating electrical wiring in a dry room, this process lasts for years. With high humidity, fire occurs within a few months.

Methods for connecting different wires

How to connect copper and aluminum wires:

• using another metal;
• preventing the appearance of harmful oxide plaque.

In the second case, special compounds are used that can protect the metal from the effects of moisture and oxidation. Pastes prevent the connection from breaking down. Another method of fire protection is tinning. Tinned stranded cable can be twisted with single-core aluminum cable. Special devices are also used for connection:

1. Clamps. Used to connect to an aluminum riser in the driveway panel. Branch clamps have punctures or lack them. The device is equipped with an intermediate plate that prevents contact between two metals. Some clamps are treated with paste. Sometimes the use of special compounds is not required.
2. Spring and self-clamping terminal blocks. Wires made of different metals can be joined and spliced ​​using terminals that have sockets and partition plates that separate the aluminum conductors from the copper ones.
3. Bolts. When making a bolted connection, a stainless or galvanized steel washer is placed between the wires.

Terminal blocks

Terminal blocks are:

1. Disposable. Used when connecting wires in junction boxes and installing chandeliers. To insert the cores into the hole of the device, you need to make an effort. Even more difficult is removing the cable from the block.
2. Reusable. There is a lever for fixation, thanks to which the cable can be inserted and removed several times. Terminals of this type are used when connecting stranded wires made of different metals. If the work is done incorrectly, the connection can be redone.

Installation is carried out as follows:

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

Soldering

This is a reliable and technologically advanced method that ensures a high-quality connection. Before soldering, the conductors are cleaned of braid and oxide film. If necessary, the cables are tinned, loosely twisted, treated with flux and soldered. It is impossible to connect aluminum and copper wires using acid flux. The composition destroys metals, reducing the strength of the fastening. The junction is isolated in the usual way.

Features of connecting wires on the street

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

How to properly connect copper and aluminum wires? Link to main publication

Source: https://odinelectric.ru/wiring/wires/kak-soedinit-mednyj-i-alyuminievyj-provoda

How to connect copper and aluminum wire the right way

There are still quite a few apartments in which the electrical wiring is made with aluminum wires. And since manufacturers of lighting devices and electrical equipment have switched to copper power cables, the question of how to connect copper and aluminum wires is still relevant today.

Due to the fact that copper and aluminum have different electrical potentials, voltage will certainly form between them. If this bundle of two metals were located in a vacuum, the connection would last forever. The same cannot be said about the air atmosphere where humidity is present.

It is a catalyst for chemical processes within the contact between copper and aluminum.

Experts have long come to the conclusion that a potential difference greater than 0.6 mV is already dangerous for wire connections. Such contact cannot be called long-term. As for copper and aluminum, the electrical potential between them is 0.65 mV, which is higher than normal. The result is a galvanic couple, like in a battery. Therefore, connecting them in electrical wiring is not allowed. But what should those who have an aluminum wiring diagram in their apartment or house do? There are several ways out.

Twisting two wires

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

You can tin both single-core and multi-core wires. In the second case, the cores must be twisted, and their number is taken into account. For large cross-section cables, three cores can be tinned; for small cross-sections (no more than 1 mm²), five wires can be tinned.

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

Threaded contact

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

We return to the electrical potential of metals and determine that between aluminum and steel (all elements of a bolted connection are made from it) the potential difference is 0.2 mV, between copper and steel - 0.45 mV, which is again less than the standard.

That is, all metals present in the bond are not at risk of oxidation. The strength of the connection between aluminum and copper wires in this case is ensured by a well-clamped nut.

Steel washers are installed between the two cores as a limiter or contact breaker.

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

How to make correct contact with a threaded connection

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

• Remove the insulating layer to a length equal to four bolt diameters. If an M6 bolt is used, the length of the open section should be 24 mm.
• If the veins already have oxidation on the surface, then they need to be cleaned.
• The ends are rolled into rings with a diameter slightly larger than the diameter of the bolt.
• Now they are put on the bolt in sequence: a simple flat washer, any one wire, a flat washer, a second wire, another flat washer, a Grover washer and a nut that is screwed in until it stops.

Please note that to clamp wires with a cross-section of no more than 2 mm² in this way, you can use an M4 bolt. If the copper wire is treated with solder, then it is not necessary to place a washer between the two wires. The end of a multi-core copper cable must be treated with solder.

Permanent connection

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

• The ends are cleared of insulation, as in the previous version.
• Rings are made slightly larger than the diameter of the rivet (maximum size 4 mm).
• The aluminum end is put on first.
• Then a flat washer.
• Copper end.
• Another puck.
• Insert the end of the rivet into the rivet gun and squeeze the tool handles until you hear a click, which indicates that the steel rod has been trimmed.

Contact in terminal block

This type of connection of copper and aluminum wire is most often used in lighting fixtures. The blocks come complete with the lamps. In terms of connection reliability, they are inferior to threaded contacts, but this is one of the simplest options.

There is no need to twist rings, or tin the ends, or insulate. It is necessary to strip the wires to a length of 5-10 mm and insert them into the terminal slots of the device. The clamp is made with a screw. You will have to make an effort, especially for aluminum wire.

If copper and aluminum are connected to each other using a terminal block, then the device cannot be laid under plaster. It can only be used in closed boxes: in a distribution box or in a lamp hood.

Wago

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

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

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

Methods for connecting aluminum and copper wires, how to connect the wires correctly, expert advice

When installing electrical wiring, quite often there is a need to connect different current conductors, namely, aluminum and copper wires. From the point of view of electrical and fire safety, this type of connection is more risky and must be carried out in strict compliance with a number of rules.

What is the essence of the problem of connecting aluminum and copper wires, and what are the options for solving it? Let's try to figure it out.

Difficulties in connecting aluminum and copper wires

Over the past decades, there has been a rapid increase in energy consumption by the population. This led to an increase in the load on electrical networks and, accordingly, on the connection of wires in electrical wiring.

Therefore, today there are serious requirements for the installation of electrical wiring aimed at increasing electrical and fire safety.

Indicators of reliable wire connection:

1. The density of the contracted contact.
2. Electrochemical compatibility of contact wires.

The first requirement of high-quality electrical wiring is quite simple to fulfill. The second requirement in practice is often ignored and incompatible current conductors are connected directly (by twisting). It is precisely because of the electrochemical incompatibility of metals that difficulties arise when connecting copper and aluminum wires.

Aluminum is a metal with a high degree of oxidation. The oxide film formed on the surface of an aluminum wire upon contact with moisture has a high resistance. This negatively affects the conductivity of the connections.

Copper is a fairly inert metal and the oxide film on copper wires has less resistance.

When paired, copper and aluminum form a short-circuited galvanic connection - when moisture gets on the contact, the aluminum wire begins to actively oxidize. A thin film with high resistance is formed between the current conductors, as a result, current conduction is hampered, the process of electrolysis occurs, cavities are formed at the point of contact, heating, and sparking of the contacts. This situation may result in a fire.

The electrochemical potential between copper and aluminum is 0.65 mV, while the permissible value of this indicator is 0.60 mV

The solution to this problem is to eliminate direct contact between the aluminum and copper wires. There are several options for connecting different conductors to ensure reliability and safety of electrical wiring.

Basic methods of connecting different current conductors

application of terminal blocks

The most common method is to connect wires through terminal blocks.

Essentially, a terminal block is an insulating plate with contacts. There are two types of fastening wires to terminal blocks:

• screw tightening (there is a risk of damage to the wire by the screw itself);
• pressing with plates (a more reliable fastening option).

The advantages of the “terminal” method of connecting wires include:

• ease of connection;
• the connection does not need to be further insulated;
• affordable cost of adapters.

The sequence of connecting copper electrical wires to aluminum:

1. Strip the ends of the wires from insulation (about 5 mm).                                                              
2. Insert the wire into the hole.
3. Tighten the screw firmly.

The terminal block is convenient to use when connecting a chandelier when the length of the conductor is too short, or for connecting broken copper and aluminum wires in the wall.

The terminal block, before hiding under the trim, must be placed in the junction box

spring terminals for connecting wires

One type of terminal block is the Wago spring clamp terminal block.

Spring terminal blocks are the most efficient and fastest way to connect wires. The main difference from conventional terminal blocks is the method of fixing the wire - a spring clamp is used. It is enough to remove the insulating layer from the conductor and insert the wire into the terminal block.

In order to connect copper and aluminum wires, it is better to use special terminal blocks from Wago. The contacts in such a terminal block are made of a bimetallic plate and coated with a special paste that prevents oxidation of the wires.

There are two types of spring terminal blocks:

1. Disposable terminal blocks. Designed for connecting single-core wires with a cross-section of 1.5-2.5 mm², the permissible current in the junction box is 24A. If the wires are removed from the terminal block, the spring clamp may become deformed and the contacts will not be able to be reconnected.           
2. Reusable terminal blocks. The design provides levers with which you can disconnect/connect wires. Such adapters are suitable for single-core and multi-core aluminum and copper electrical wires with a cross-section of up to 4.0 mm², permissible current strength - 34A.                                                                                                               

The disadvantage of terminal blocks with a spring mechanism is their cost; they are an order of magnitude more expensive than conventional adapters.

connection via nut

To connect wires with a large cross-section (4 mm² or more), you can use a branch clamp, known in everyday life as a “nut”. It is an oval-shaped plastic case, inside of which there is a block of metal plates. Aluminum and copper wires are clamped between the plates using screws.

This connection option is not entirely convenient due to the large dimensions of the adapter itself, which is difficult to hide under the decoration of the room: skirting boards and boxes.

permanent connection

The permanent connection is made using a special tool - a riveter.

The operating principle of the rivet maker is simple - retracting and then cutting off a rod that passes through a tubular rivet with a head.

The wire connection technology is as follows:

1. Remove the insulation from the conductors (the cleaning length is equal to 4 diameters of the future rings). It is optimal if the diameter of the rings is slightly larger than the diameter of the rivet.
2. Twist rings from the cleaned ends of the wire.
3. Place all the elements on the rivet in the following order:
   • aluminum wire;
   • spring washer;
   • copper wire;
   • flat washer.
4. Insert the steel rod into the rivet gun and squeeze its handles until a characteristic click is heard.
5. Exposed areas of the connection must be insulated.

The reliability of the permanent connection is very high; the only drawback is that it is not possible to disconnect and re-fasten the wires.

Alternative ways to connect aluminum and copper wires

If you don’t have special adapters or a riveter at hand, you can use alternative methods of connecting different conductors.

The bolted connection is considered quite durable and safe. Among its advantages are ease of installation and versatility (in this way you can connect almost any type and brand of aluminum wires with copper).

Bolted connection technology:

1. Remove insulation from conductors.                                                                                       
2. Clean the metal from oxidation.
3. Form rings.
4. Place the following elements on the screw:
   • spring washer;
   • simple washer;
   • a ring of one wire;
   • simple washer;
   • a ring of another wire;
   • simple washer;
   • screw.
5. Tighten the screw.

To connect conductors with a cross section of less than 2 mm², an M4 screw is suitable

A technologically more complex and labor-intensive method is applying solder to a copper wire. Lead-tin solder can be used.

When aluminum comes into contact with lead-tin solder, the electrochemical resistance is 0.40 mV (the permissible limit is no more than 0.60 mV)

The sequence of connecting the wires will be as follows:

1. Remove the insulation from the wires (cleaning length is about 6 cm).
2. Using a heated soldering iron, apply solder to the copper conductor.                                  
3. Tinned copper wire can be twisted with aluminum.

This method can be used if there are no jumpers or the bolted connection does not fit into the box. However, for electrical wires with significant loads, such a connection cannot be used.

Features of connecting wires indoors and outdoors

Wire connections located outdoors are exposed to external factors and require additional protection.

The optimal solution for connections on the street is the use of branch clamps for SIP. The material used to make the clamps is resistant to ultraviolet rays and low negative temperatures.

In addition, nut branch clamps are also suitable for outdoor use.

To connect wires in a room, you can use different conductors. One of the most convenient is the Wago self-clamping terminal block.

Expert advice: how not to connect aluminum and copper wires

There are frequent cases of the use of dangerous, unacceptable methods of connecting aluminum and copper wires, which had very sad consequences. These methods include:

1. Twisting copper and aluminum wire. It should be noted that a number of experts do not recognize twisting, even if a layer of soldering is applied to the copper wire.
2. Twisting of wires and subsequent protection of the connection point from moisture. Some “craftsmen” use paraffin, oil or varnish as waterproofing. This method is unacceptable and, to put it mildly, ineffective.

Today, the problem of connecting different current conductors is solved very simply and quickly - just purchase one of the special adapters. Therefore, it is completely inappropriate to waste time and try untested methods, jeopardizing the safety of not only the home, but also the people living in it.

Source: http://strgid.ru/sposoby-soedineniya-alyuminievogo-i-mednogo-provodov-kak-pravilno-soedinit-provoda-sovety-spetsialis