If you combine aluminum with copper. You can connect aluminum and copper wires without any problems. How to properly connect copper and aluminum wire

Aluminum wiring is often used in construction when laying power lines, including in residential buildings. In order for such cables to be reliable and serve for a long time, you need to know the features of their operation.

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What is the difference between copper and aluminum wiring?

The main differences in electrical wiring in modern apartments are as follows:

• duration of cable operation;
• the amount of power and maximum load on the wires;
• the value of electrical potentials.

Service life and operation of wiring

For aluminum cables, the average service life in accordance with the standards specified in SNiP is about 10-15 years. Copper conductors last an order of magnitude longer - around 20-30 years. The overall service life of cables is affected by their operating conditions. If the wiring is regularly subjected to high loads, as well as aggressive external conditions, then the service life will be significantly shorter.

This means the following impacts:

• sun rays;
• low negative temperatures;
• rain and moisture (during fog, for example);
• high temperatures.

If all SNiP requirements are met and the power supply to the network is not critical, then the service life of the wiring will be up to one hundred years. Moreover, much in this matter depends on the correct use of electrical equipment and automatic machines.

The channel “Sami with a Mustache” spoke in detail about the need to replace electrical cables and their service life.

A cable with a core cross-section of 2.5 mm can withstand a current of up to 25 amperes. If a 16 A circuit breaker is installed in the apartment, it will break out before the wire heats up to a critical temperature at high power. Automatic equipment rated for 40 amps will work, but the cable will melt if a current of 32-35 amps passes through it.

Table of electrochemical potentials (mV) arising between connected conductors

The standard values ​​for the main technical parameters when connecting cables are given below.

Material: copper.

			Voltage parameter 380 V
	Current parameter	Power value	Current value	Power level
1,5	19	4,1	16	10,5
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	46	10,1	40	26,4
10	70	15,6	50	33
16	85	18,7	75	49,5
25	115	25,3	90	59,4
35	135	29,7	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66	260	171,6

Material: aluminum.

Wiring connection cross-section size	Voltage value is 220 volts		Voltage parameter 380 V
	Current parameter	Power value	Current value	Power level
2,5	20	4,4	19	12,5
4	28	6,1	23	15,1
6	36	7,9	30	19,8
10	50	11	39	25,7
16	60	13,2	55	36,3
25	85	18,7	70	46,2
35	100	22	85	56,1
50	135	29,7	110	72,6
70	165	36,3	140	92,4
95	200	44	170	112,2
120	230	50,6	200	132

Pros of aluminum

This material for laying wiring has certain advantages:

1. Ease. Compared to other materials, aluminum wiring has significantly less weight.
2. Resistant to corrosion. Aluminum material is less susceptible to destructive effects. When this type of conductor interacts with air, oxidation occurs. But due to the formation of a film on the cable structure, the material is reliably protected from further destruction.
3. Price. Aluminum itself is an inexpensive metal. Therefore, it has found wide application in the manufacture of power conductors. Due to its light weight and affordable price, aluminum is considered the best option for laying air inlets.
4. Large selection of different types of conductors. If, when renovating a room, it is necessary to install and connect power cables, then you can use SIP-type products. To implement internal wiring, the APBPP, APPV, and APV options are used.

The Chipdip channel spoke about the features of using such cables, as well as their advantages.

Disadvantages of aluminum

This material has both pros and cons, they are considered in accordance with the reviews:

1. Low level of electrical conductivity of aluminum wiring. For this material this figure is 38*106 S/m. If compared with copper conductors, then this value will be 59.5 * 106 S/m. As a result, the latest cables with a diameter of 1 mm2 will be able to carry almost twice as much current as aluminum products.
2. Low flexibility of conductors. Because of this, the use of aluminum cables is not allowed in places where the wires will be subject to repeated bending. To maximize the integrity of the product, the laying route must be straight. It is important that during use the conductor is minimally exposed to various mechanical influences.
3. Aluminum cables are characterized by reduced fluidity properties. Due to constant mechanical and thermal influences, such a conductor will lose its shape over time. As a result, this will negatively affect the twisting area and contact connections.

User Vladislav Rezanov spoke about residential electrical wiring made of copper and aluminum, as well as the disadvantages of both materials.

Need to replace wiring

It may be necessary to change cables in an apartment or house in the following cases:

1. The period of use of the wires came to an end, which led to the destruction of the insulating layer. As a result, the old cable overheats and melts, especially when it comes to aluminum conductors.
2. When carrying out electrical installation work. If the quality of the electrical network is satisfactory or worse, it is recommended to change it.
3. As a result of cable breakage. This process will cause the appearance of areas where current leaks will occur.
4. There is a possibility of a short circuit. This is usually due to broken conductors and destruction of the insulating layer.
5. A section of cable caught fire. This will be indicated by sparking, as well as a burning smell.
6. The automatic switch or protective shutdown device often trips.
7. The electricity in a house or apartment is constantly cut off, for no apparent reason.
8. More powerful electrical equipment is being installed in the room. If the old wiring is not designed for it, it is recommended to install a new one.

Is it possible to connect copper and aluminum wiring?

When these two materials come into contact, a chemical reaction occurs, which ultimately leads to a deterioration in the quality of electrical contact. As a result, the junction of the conductors will become very hot due to the passage of current. As a result, this can lead to cable ignition and even fire. If there is high humidity in the room, this process goes much faster. This is due to the fact that a thin film appears between the conductors, which is characterized by increased resistance, and therefore leads to heating and breakage.

If you correctly approach the process of connecting a copper conductor to an aluminum conductor, then all these problems can be avoided.

In any case, you should completely replace the old cables with new ones. The wiring must have the necessary load capacity, which will correspond to the current consumption of electrical equipment. If it is not possible to immediately replace all cables, then you can resort to a partial replacement process. Then you will need to correctly connect two different types of conductors.

Methods for connecting different wires

To connect cables made of different materials, you can use one of several methods:

• by using terminal blocks;
• by twisting with tinning of a copper conductor;
• by carrying out a crimping procedure;
• bolt connection method;
• threaded connection.

Threaded connection of two different cables using a bolt Using a terminal clamp to secure conductors Crimping method using special sleeves

Terminal blocks

This connection option is considered quite popular, but cannot boast of maximum reliability. However, it has many advantages. By connecting using terminal blocks, you can quickly and reliably connect aluminum and copper conductors to each other in any combination. To complete the task, you do not have to form rings at the ends of the cables, or isolate the connection point. This is due to the fact that the terminal clamp device prevents the bare parts of the cables from touching each other.

The use of such blocks is advisable when connecting lamps to short aluminum cables that come out of the wall or ceiling. As a result of repeated twisting, such conductors lose flexibility and break, which leads to a decrease in their length. If the cable extends 1 cm from the surface of the wall or ceiling, using a terminal clamp will ensure a high-quality and reliable connection.

The connection procedure is performed as follows:

1. The end of the conductor is stripped of the insulating layer by approximately 5 mm. To do this, you can use a stationery knife or a special device.
2. The end of the cable is then installed into the hole in the terminal clamp.
3. The conductor is fixed by tightening the bolt on the block. When performing this task, it is important that the effort be significant.

It is not allowed to hide terminal blocks under plaster without installing them in the distribution panel.

The Radio Amateur TV channel spoke in detail about the use of such fixation elements.

Tinned copper wire

This method is simple to implement. Its implementation does not require the user to use additional devices other than a soldering iron. But practice shows that the twisting method is unreliable, especially if the wires are made of different materials. This is due to the fact that various metals can change their sizes as a result of temperature changes. This leads to the fact that over time a gap forms at the connection point, which increases the value of the contact resistance.

As a result, heat will be generated, the conductors will oxidize, and their connections will be damaged. When performing this task by twisting, an important rule must be taken into account - the cables must wrap around each other. If one conductor is straight, and the second wraps around it, then the connection point will become unreliable - this option is not suitable. The implementation of this method is allowed when connecting cables with different diameters. It is possible to connect conductors with one or several cores, but the latter must be tinned in advance using solder, this will make it single-core.

When implementing a task, the number of turns must be chosen taking into account the diameter of the cable. If this value is 1 mm, then at least five coverages must be made. When the conductor is thicker, it is necessary to provide at least three turns.

User Valera shevchenko spoke about the nuances of tinning and clearly showed the procedure for soldering cables.

Crimping method

This connection method involves the use of sleeves. Its implementation is the most expensive due to the need to use special devices. In practice, installing a sleeve allows you to ensure reliable and high-quality contact that will last for many years. In industrial plants, this method is often implemented with wires connected to high-voltage, high-power equipment.

To complete the task, you will need aluminum-copper sleeves, as well as special tools.

Features of the choice of sleeves:

1. If you are connecting conductors of different cross-sections, then you need to select the right connecting element. Sleeves can have different diameters and inlet hole sizes.
2. The connecting elements must have a certain length. The sleeves do not have a reserve, so they cannot be cut into several parts to save money. When connecting two conductors, crimping must be done twice with opposite elements. If you cut the sleeve, this will not work, resulting in poor quality contact.
3. The use of connecting elements is allowed when connecting single-core and multi-core cables. The main nuance is to choose a sleeve with the necessary input parameters. Since conductors usually have different cross-sections.

The Electrician's Advice channel talked about the choice of sleeves and the implementation of the method of crimping conductors in practice.

Bolted connection

This option will allow you to ensure high-quality contact using available materials, without the use of special devices and tools. To complete the task, you will need a regular bolt with two or three washers and a nut. The main nuance is to separate two different metals using washer elements. This type of connection is recommended to be implemented in a distribution panel.

The procedure is performed like this:

1. A layer of insulation is removed from the conductor to a length corresponding to four bolt sizes.
2. The condition of the veins is diagnosed. If they are acidified, then it is necessary to clean the metal component until it shines. Rings are made at the ends of the veins.
3. Then a regular spring washer is installed on the bolt one by one. A core ring of one conductor is mounted on top.
4. A regular washer is put on. Then a core ring of the second cable, another washer element and a nut are installed. The latter is used to tighten the bolt. Tightening is carried out until the spring washer is completely straightened.

In the case when the size of the conductor core is no more than two millimeters, M4 class bolts are used. If two cables made of the same metal or aluminum and copper are connected, and its end is tinned, the use of a washer between the rings is not necessary. In the case when a copper conductor with several cores is used, it must be tinned in advance using solder.

Aluminum Wiring Connection

To complete this task, you can use all the methods described above. The use of special spring connections is also allowed. To do this, the stripped conductor cores are installed in the holes of the terminal blocks. Due to the presence of a spring in the device, the consumer does not need to re-tighten the contact. On sale you can find different types of terminal blocks, which are divided into disposable and reusable.

The former are used to connect cables without the possibility of their subsequent disconnection. The end of the core is installed in the hole on the terminal, where it is secured. To disconnect, the wire will have to be cut. If we talk about reusable devices, they can be used several times. To fix the conductor, you need to lift a special lever, install the stripped end of the cable into it and lower the fixing element back.

To connect aluminum cables, you can resort to the soldering method:

1. The process of completing the task is not easy. Its difficulty lies in removing the oxide from the surface of the conductor. Abrasive materials are used. But when removing the oxide, you cannot overdo it, as this will lead to the appearance of a new film, but you need to reduce its thickness.
2. Then the two ends of the conductors are fastened using flux and solder. As a last resort, experts recommend using COP or other similar options.
3. To work with aluminum, you will need flux F-59A, F-61 or F-54. In their absence, similar compositions are used. This flux allows you to effectively remove the oxide film.
4. Solder must be scraped across the surface of the conductor. This will make the oxide removal process easier. If flux is not used when performing a task, then the solder must be used more intensively.

Is it possible to twist aluminum wires?

Connecting these types of cables to each other is not prohibited. Their connection to each other is more secure than copper and aluminum conductors.

Features of connecting wires on the street

When laying cables outdoors, it is necessary to take into account the negative impact of external factors on the cable line. Icing and exposure to rain will reduce the service life of wires. Therefore, installation and connection work must be carried out in sealed and closed structures. The wiring will be as resistant to low temperatures and sun rays as possible. If connections are made on poles or on roofs, it is recommended to use special piercing clamps.

The Electrician's Tips channel spoke in detail about the implementation of a hermetic connection of two conductors.

Is it worth replacing old aluminum wiring or not?

If the wiring is outdated, then it must be replaced. Cables that were laid 20 or more years ago will not be able to withstand the load in modern houses and apartments.

This is due to the use of higher power as a result of the installation of such household appliances:

• boilers;
• microwave ovens;
• computers;
• air conditioners.

Briefly, the wiring replacement algorithm looks like this:

1. At the first stage, you need to prepare for electrical installation work. It is necessary to completely study the room where the wiring will be installed. The condition of the components should be assessed and the load on the electrical network should be calculated.
2. Then technical documentation and a project are drawn up. It is recommended to entrust this task to qualified specialists. When implementing it, the parameters of household equipment and appliances that are installed in the future are taken into account. Places for installation of electrical points and lighting devices are marked.
3. A full estimate is drawn up, as well as the purchase of materials that will be required to complete the task. Experts advise purchasing wires with a rigid and solid core. Cables for sockets are selected with a cross-section of 2.5 mm2. To connect lighting equipment, conductors rated at 1.5 mm2 are laid. To ensure high-quality operation of powerful devices, you will need cables with a cross-section of 4 mm2.
4. We must not forget about additional equipment. We are talking about automatic devices, installation boxes, RCDs and other components.
5. The next stage is laying the cables. If a closed installation is carried out, then it is necessary to groove the walls. When implementing open wiring, the cables are laid in special channels. At this stage, the installation of electrical equipment is carried out. We are talking about switches, junction boxes, sockets.
6. A new power line is being connected; the ends of the conductors need to be connected. Before closing the electrical channel after connection, you need to check the operation of all devices. If testing shows problems, it is easier to get rid of them immediately.

User Electroconductor 116 clearly demonstrated the procedure for replacing wiring in a three-room apartment.

Security measures

Tips for safely connecting two types of cables to each other:

1. If the connection is made by soldering, then you need to remember one thing. Tinning copper is a simple process. In the case of aluminum, you will have to use special solder.
2. When performing the task, strong squeezing of the cable connections is not allowed. Some consumers do not understand why this cannot be done. This leads to deformation and damage to the conductors, resulting in possible loss of current.
3. When making connections, you must follow the markings and select the correct terminal clamps. The cross-section of the core is taken into account, as well as the installation method - in the house or on the street.
4. It is not allowed to use the conventional twisting method when connecting conductors made of different materials. This option is unsafe and will lead to heating and fire.

Video “A Practical Guide to Connecting Wires”

The Electrician's Tips channel talked about ways to connect cables made of different materials and clearly showed the process of performing this task.

Modern electrical wiring in an apartment or house is carried out only with copper wires, as the PUE says. But in old houses, wiring was most often done with aluminum wire, and a situation arises in which it is necessary to connect 2 wires of different materials. And in this article you will learn how to connect copper and aluminum wire in different ways.

Is it possible to twist copper wire with aluminum

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

If you ask yourself which wiring is better, copper or aluminum, then the choice is, of course, copper. This comes out of the technical characteristics of copper; the cross-section of aluminum wire under the same conditions has to be taken larger. There are also disadvantages: copper is more expensive. It is easier to distinguish copper wire from aluminum by color; copper has a reddish tint, aluminum is gray and white.

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

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

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

Galvanic pair - 2 metals of different kinds, the connection of which will lead to increased corrosion. Copper and aluminum are just such a galvanic pair. The electrochemical potentials of the two metals are too different, so rapid corrosion will increase the resistance at the junction and subsequent heating. More details about the compatibility of metals are indicated in GOST 9.005-72. Below is a table with some data on metals:

Galvanic compatibility of meltals

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

Connecting wires

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

Methods for connecting conductors with different electrochemical potentials:

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

WAGO

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

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

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

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

Twisting wires

Twisting aluminum and copper wires was previously mentioned as a very unreliable connection method, but sometimes this is the only way to quickly restore power supply.

A couple of tips before twisting:

• Before twisting, the copper wire should be well tinned.
• The amount of twist must be at least 5 turns.
• After work, the joint must be protected with several layers of insulating tape or heat shrink tubing.

Soldering copper to the terminal block

You can solder copper and aluminum together. If everything is clear with copper, then for soldering aluminum you need a special flux. Some electricians simply solder copper wire to the terminal block.

Flux for aluminum

Terminal blocks

The list of electrician tools and consumables includes terminal blocks. Terminal blocks are copper or brass coated with a layer of nickel, designed for wires of a certain cross-section and covered with a layer of insulating plastic. The wires are secured with 2 small screws.

When connecting copper and aluminum terminal blocks, the locking screws must be properly tightened. If you tighten them, you can damage the aluminum conductors, which will not have a very good effect on the further operation of the electrical wiring. Therefore, it is necessary to find a middle ground: not tighten too tightly, but achieve high-quality contact.

Bolted connection

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

To connect two wires you will need: a bolt, a nut, 3 washers. Sequence of actions:

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

Bolted connection of aluminum and copper

Nut connection

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

Copper and aluminum wire, as well as a branch wire, are placed between the plates. But you can simply use the “nut” as a connecting element. After laying the conductors, the plates are tightened with bolts. As insulation, a plastic case is placed over the entire structure, consisting of two halves, for fastening which standard screws are used.

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

Crimping

For this method you will need special crimping pliers and sleeves. The principle of connecting wires with a sleeve is very simple: an aluminum wire is inserted into the sleeve on one side, a copper wire on the other, and the sleeve is crimped on both sides with pliers. There are sleeves for wires with a large cross-section - from 16 mm 2 to 300 mm 2, but in this case a special hydraulic press will be required. The only drawback of crimping is the high cost of the tool.

Special sleeve for connecting aluminum and copper

Lubrication

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

But this paste can be used for all types of connections (threaded, using terminal blocks, crimping), especially if the connection occurs outdoors. Then the contact is affected by additional factors that significantly reduce the durability of the connection. Although the use of lubricant without insulation raises doubts.

Bottom line

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

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

Danger of poor wire connections

The industry produces two types of wires for household purposes, copper and aluminum. The former have less resistance, which makes it possible to use a smaller cross-section for the same load. They are more resistant to mechanical loads, this makes it possible to twist them repeatedly without fear of breaking at the cut site. The latter have one advantage - comparative cheapness. But sometimes it plays a key role. What can happen if the connection is poor quality?

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

Methods for joining copper and aluminum

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

• twist;
• threaded;
• terminal;
• one-piece.

Twisting wires

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 core must not be left straight. There is a rule - thick wires must have at least three turns, thin ones (from 1 mm or less) - five. To reduce oxidation of the conductor, the copper core is soldered to the length of the twist. The same rule applies to multi-core copper cables.

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

Threaded method

A more labor-intensive connection compared to twisting. Requires a tool and some skill. Has greater mechanical strength. Electrically, it is better than twisting. Allows you to immediately connect a large number of wires of different cross-sections. Both single-core and multi-core can be connected.

For connection, a bolt is used, onto which the conductors are put 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 placed on the last conductor. The entire package is tightened with a nut until the spring washer is straightened. Further compression may lead to conductor breakage.

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. Stranded copper wire also needs to be soldered, then it will not fall apart when compressed.

After assembly, it is necessary to take measures to prevent short circuits with adjacent packages. Over time, it is necessary to check the condition of the spring washer; if it is loose, tighten the nut. This connection prevents sparking and allows wires to be routed in different directions. If necessary, it can be easily disassembled and assembled without damaging the conductor.

Terminal method

The terminal connection is manufactured in factories. Has a wide range. Two groups can be distinguished:

• pads;
• terminal blocks.

Pads have different shapes and designs. The idea 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 rigidity of the structure.

The advantage of the pads is that no preliminary steps are required, except for stripping the cores. The connection occurs quickly, without requiring any skills. They are indispensable if the conductor is short (connecting a chandelier, restoring a broken wire). If they are located in distribution panels or metering panels, 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 loads than a threaded connection;
• each block is designed for a conductor of a certain cross-section;
• you cannot connect large and small diameter wires at the same time;
• take up more space compared to previous options.

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

• reusable;
• for one-time use.

Reusable The terminal block is a completely insulated block. Instead of screws, a spring plate is used, which is pressed out using a plastic lever. After which the wire is inserted into the opening. In some versions, 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. Intended for one-time use. If the wire is 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 preparation required;
• ease of use;
• the necessary insulation is ready.

Flaws:

• the method is the most sensitive to mechanical loads;
• compared to other connections it is the most expensive;
• sensitive to high current and, according to user comments, cannot withstand the regulated load.

One-piece method

Perhaps the most time-consuming method. Requires special knowledge and skills. Special tools and devices are required. This method includes:

• riveted;
• soldering.

Riveting very similar to a threaded connection, the only difference being that a rivet is used instead of a bolt. The ends of the wires are cleared of insulation and sanded with sandpaper. When combining aluminum and copper wires, the latter is tinned. This also applies to copper stranded wire. After that, rings are made with a slightly larger 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 connection reliability and low resistance are required. Similar to twisting, but the wires are soldered together. This cannot be achieved in the usual way for aluminum, so the wires must be prepared.

To do this, you will need a solution of copper sulfate, a small non-metallic container, and a DC voltage source of 9-24 V. Pour the solution of copper sulfate into the container and lower the pre-cleaned conductors to the length of the twist. We connect the copper wire to “+” so that electrons come 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 which both wires are coated with a layer of tin. A twist of 3 turns is made for a thick wire and 5 turns for a thin one (less than 1 mm). All this is carefully soldered. All that remains is to cover them with waterproof varnish, insulate them - and the connection is ready.

Advantages:

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

Flaws:

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

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

I know what the topic is among themselves is as old as the hills, but I would like to touch on this topic and consider ways to connect wires from different materials.

When renovations begin in an apartment, the question arises of repairing or replacing (full or partial) electrical wiring. Someone wants to move sockets or switches, or add new ones. In this case, you cannot do without connecting the wires. This is where the fun begins.

As you know, in old houses built in the Soviet Union, all electrical wiring was made with aluminum wire. Why? Aluminum is a cheap material, has good conductivity, is chemically resistant, and lightweight, so there were no installation difficulties. True, the load in the apartments was small. With the development of technology, various powerful devices appeared, and the use of aluminum wires became impractical. Therefore, copper wires began to be used in apartments.

When repairing or replacing electrical wiring, it is necessary to use copper wire. It’s good if the wires are completely replaced. But what if we only partially change the wires? After all, then we need to connect the aluminum wire with the copper wire to each other.

Previously, aluminum wires were connected using conventional twisting. Then they began to connect copper wires as well. But you can’t connect copper and aluminum wires by twisting them,

Although many electricians used to do this (and still do it now). Moreover, at present, twisting is generally prohibited by the rules (PUE). Someone will say that this paragraph of the rules does not directly prohibit twisting, but twisting is not specified. as one of the ways to connect wires, therefore it is considered that twisting is PROHIBITED!!!

Why can't you connect wires by twisting?

Each material has such a property as linear expansion - a change in linear dimensions with temperature changes. Copper and aluminum have different coefficients of linear expansion, therefore, when current flows through the twist, over time the contact between the wires weakens, the gap between the wires increases, the resistance at the contact point increases, the contact point heats up, which in the future can lead to destruction of the contact and burning of the insulation wires In the photo on the left you can see how the electrical tape on the aluminum-copper twist has been burnt. And on the right is the same twist after removing the burnt electrical tape.

And now it’s not far from disaster – a fire. Therefore, if an electrician offers you connect aluminum and copper wires twist it and wrap it with electrical tape, then drive him out of your apartment by the neck.

How to properly connect aluminum and copper wires to each other?

There are several ways to connect wires made of different materials:

Each of these methods has pros and cons. Let's consider each of them separately.

Bolted connection

For such a connection you will need a bolt and nut, several steel washers that will need to be placed between the wires, and electrical tape to insulate the connection. To make a bolted connection, you need to make rings at the ends of the wires of such a size that they will accommodate the bolt with which the connection will be made. Then we assemble our structure, placing washers between the wires, and using wrenches we tighten the nut and get an excellent connection, which is also very reliable. One drawback: the connection is bulky and very difficult to push into the junction box.

Screw connection

This type of connection is made using screw terminals (terminal blocks),

which are isolated from each other. Screw connections of wires are usually found in lamps and chandeliers. Screw terminals are brass tubes with a plastic housing. The tubes have two screws for fastening the wire. In this way, you can connect wires not only from different materials, but also homogeneous ones.

Disadvantages of this connection:

— the plastic housing of the terminal block may burst, and the insulation will accordingly be damaged;

— the brass tube itself may burst. This happens. When you tighten the screws too hard;

— the screw can crush the wire when tightening, and it will subsequently break off. Moreover, this applies not only to aluminum, but also to copper wires;

- You can break the screw when tightening. Then there is no need to talk about good contact;

- if you apply insufficient force, you may not tighten the screw and get poor contact.

Screw terminal blocks are convenient to use as a temporary connection or for connecting lamps. They also help out if you need to repair a broken wire whose tip is sticking out of the wall.

Connection using WAGO terminal blocks

WAGO terminal blocks appeared in Russia not so long ago, although the first screwless terminal blocks were developed in Germany in 1951. There are many self-clamping WAGO terminal blocks, but we are only interested in those that are suitable for connections of aluminum and copper wires.

These are special terminals of gray or black color, inside of which there is conductive paste. This paste prevents oxidation of aluminum wires. These terminal blocks are disposable, although they can be reused if desired. However, the quality of the connection deteriorates.

WAGO self-clamping terminal blocks have many advantages:

• fast and accurate installation;
• the connection does not need to be isolated;
• you can connect wires of different materials and different sections;
• the connection can easily be redone if necessary;
• connection with WAGO terminal blocks is less than twisting.Therefore, it is easier to fit in the distribution box (see photo);

• can be used to connect multiple wires (2 to 8)

The only drawback of these terminals is their cost. Therefore, many electricians use screw terminal blocks and even twist them. But I believe that this disadvantage is compensated by the advantages, and there are significantly more of them.

My colleagues and I, who carry out electrical installation work in Syzran, use exactly WAGO terminal blocks for connecting aluminum and copper wires.

If you need someone who will do everything correctly and accurately, then you can contact me using the information on. You can also ask questions in the comments to this article. I will be happy to answer them.

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

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

This issue - copper and aluminum - is faced not only when installing internal electrical wiring, but also when replacing the input into the house

The fact is that the overhead line (OHL) wires are aluminum, and if you are making a copper input cable, then you can’t just screw the cable core onto an aluminum wire!

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

Yes, indeed, but why? Here's why.

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

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

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

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

It turns out that when copper and aluminum wires are connected, they come into contact with their oxide films.

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

The transition resistance in the twist already “slowed down” the electric current, and even weakening the contact further increased the value of the transition resistance.

This causes the twist to begin bask The further you go, the more the wire insulation heats up. It is destroyed by heat and can even burn.

You know how many houses have burned down due to faulty electrical wiring, and often it is the transition resistance or poor contact that is to blame.

Speaking of transition resistance.

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

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

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

Remember - transition resistance is an analogue of a red-hot nichrome thread.

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

The point here is this: the main thing is that these two metals didn't touch among themselves. Between them there must be a material neutral in relation to them, naturally conductive.

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

By the way, it’s interesting - you can’t: zinc, carbon (graphite) and silver with gold and platinum.

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

In this case, if there is a lot of money, it is better to make the wires entirely from platinum, the voltage losses will disappear completely)))

So, we combine copper with aluminum:

-Using terminal clamps;

-Bolt connection via washers

- Layer of neutral material

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

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

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

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

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

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

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

I’ll show you how to do this in the photo:

This is a good way out when you don’t have clamps at hand or don’t want to use them, and the bolted connection doesn’t fit in the box.

Then you need to cover the copper wire with solder and twist it with aluminum - the connection will be reliable! Although according to the PUE it is incorrect...

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

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

So the state is as if it had just happened!

Everything is clean, no oxidation or scorch. I think this is because the apartment was always dry and besides, the junction box was tightly sealed in the wall, that is, air did not penetrate into it.

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

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

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

So now you knowhow to connect copper wire to aluminum and if you have to do this, I’m sure you will make the right choice!

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