How to properly connect copper and aluminum wires - options and devices. Is it possible to connect copper wire to aluminum? What is the best way to connect aluminum wires to copper wires?

Any cable consists of aluminum or copper current-carrying conductors. According to the electrical installation rules, the usual twisting of such wires is strictly prohibited. But there are situations during installation when there are no options other than connecting aluminum and copper wire. There are many such opportunities. All that remains is to choose an accessible and safe one.

Electrochemical destruction of metals

The opinion that it is impossible to combine aluminum and copper is often mentioned. This is true from the analysis of the chemical compatibility of metals. In the world of modern technology, you can find dozens of matings of metal pairs.

There is a concept of electrochemical potential difference, the indicators of which are summarized in a special reference table. Take from it as necessary indicators and are determined with compatibility:

• Copper - lead-tin solder 25 mV.
• Aluminum - lead-tin solder 40 mV.
• Copper - steel 40 mV.
• Aluminum - steel 20 mV.
• Copper - zinc 85 mV.

To imagine what is happening, it is necessary to understand the reactions that electrodes made of different metals undergo upon contact.

In the absence of moisture, the reliability of contact is undeniable. But there is no ideal situation. Atmospheric humidity always negatively affects the quality of connections. Any conductor has a certain electrochemical potential. This property is used in practice in the operation of rechargeable batteries.

Getting onto the contacting surfaces from various compounds, water creates a short-circuited galvanized environment. One electrical conductor begins to deform. The material from which it is made is also subject to destruction.

Methods for connecting wires made of different metals

Technological rules allow direct connection of different metal conductors with an electrochemical potential coefficient of over 0.6 millivolts. According to the tabular data, for a combination of aluminum and copper it is equal to 0.65 mV, which makes such a combination unacceptable. However, there are ways to correctly interconnect different wires.

Cable connection by twisting method

Most famous, but an unreliable technique is called twisting. This method does not require special skills and is easy to make. For these reasons, it is used quite often. Before connecting the aluminum wire with copper, you need to imagine what is happening in a similar combination with temperature changes and precipitation:

• There is a gap in the connection.
• Increased resistance at the ligament point.
• Heat.
• Oxidation of cables, destruction of contact.

This method is not suitable for ensuring secure communication. Although, if you perform certain operations, in some cases you can use twisting to connect aluminum and copper wires:

Threaded connection of wires

A similar method is performed by clamping the ends of the cable into a bolted fastening. This is the most reliable connection between aluminum and copper wires together. It guarantees tight contact for the entire period of use of the twist. Replacing bolts of different lengths makes it possible to combine an unlimited number of cables:

• Different sections.
• Stranded and monolithic.
• With washers to prevent direct contact with copper and aluminum conductors.

Procedure:

1. Cut the insulating coating to the length required for fastening.
2. Sand and degrease the cleaned areas. Tin the multi-wire cable. Connect the cores using threads through steel washers.
3. Tighten the nut tightly.
4. Shock absorbers are placed in front of the outer washers to prevent pinching and breaking of the wire. When crimped, it will straighten and the connection will be fixed.

Connecting different cables with a terminal block

Splicing cables through terminal connections has become widespread in recent times. Although the quality of contact it is inferior to the bolted one, there are also undeniable advantages:

• The wires are connected in random order.
• There is no need to make connecting rings and put on ferrules.
• The design features of the terminal blocks do not allow short circuits of the wires.
• Isolation of the contact point is not required.
• The work on connecting the terminal contacts is simple.

The ends of the wires are exposed by approximately five millimeters, inserted into the clamp and pulled through. This method is indispensable when connecting aluminum cables, the cores of which break due to repeated bends.

Repairing damaged cables using terminal blocks also turns out to be the only acceptable option due to the short length of the wires. After splicing, a junction box is installed.

From the numerous connecting devices, not least occupied by the German Vago spring terminal blocks of the same company. They are either disposable or with a clamp for repeated splicing of the wire. Such terminal blocks are used when working with single-wire wires with a cross-section from one and a half to two and a half squares made of any metal in insulating boxes. According to the passport, they are designed for twenty-four amperes in load. The contacts are treated with a special compound to prevent oxidation.

These are the simplest devices to use. The wire is stripped and forcefully inserted into the block. The fixation is reliable. It is possible to get the wire out with good effort. The spring block is destroyed and reuse is impossible, which is the biggest drawback of this product.

Wago reusable terminal blocks with an orange lever are designed for the use of wires of any type with a cross-sectional area of ​​up to four square millimeters and currents of up to thirty-four amperes. Apply repeatedly until completely worn out.

The method of application is available to anyone. The insulation is stripped to a distance of approximately ten millimeters, the lever is raised, the wire is placed in the channel and the lever slams shut. The connection is fixed.

Vago terminal blocks are effective devices for installation of electrical networks. They do not require the use of special tools, but are quite expensive.

Monolithic connection method

The technique for making such a connection is similar to a threaded one. A rivet and a special device - a riveter - are used as a fastening element. The rivet is a hollow aluminum rod, thickened on one side. A wire pin with a cap is placed in it. When passing through the cavity, it creates a thickening on one side. Then the pin breaks off, forming a rivet.

If you do not take into account the price of the riveter, this method of contact becomes the most affordable besides twisting. The disadvantage of such contact is its disposability and the impossibility of disconnection if the work is performed incorrectly.

The use of special copper sleeves will be another way to permanently connect conductors. They are produced in various sizes, each with its own cable section. The bare ends of the wires are threaded through them and crimped with special pliers. This method is the most compact along with twisting.

Connecting wires by soldering

If desired, dissimilar wires can be soldered. This method must take into account certain technological features. Before connecting the wires correctly, aluminum and copper must be prepared for soldering. Copper doesn’t require any special tricks. Aluminum wire is another matter. On its surface, under the influence of ambient air, an oxide film - amalgam - is formed. It resists chemical attack and solder does not stick to it.

To neutralize it, you will have to make a simple device. The tip of the aluminum wire is stripped and treated with a solution of copper sulfate. Take a battery and attach this conductor to its minus. The copper wire is fixed to the positive with one end, and the other is dipped in the same solution. After a certain period of time, the aluminum will be covered with a copper coating and will become available for soldering.

Specifics of connections for outdoor installation

Electrical connections in outdoor installations are exposed to various weather conditions. Insulation requirements are more stringent. To prevent short circuits, a Walnut clamping kit is used.

Its plastic shell contains metal clamps in which the wires are connected by tightening the screws. The housing halves are tightly compressed with screws or spring rings. Such a cocoon guarantees protection from external weather fluctuations. This is a rather large connection, but in outdoor conditions it is not critical.

When installing electrical wiring, sometimes the question arises about connecting copper and aluminum wires. This issue is especially relevant during electrical work in old housing stock, where the main part of the electrical networks is made of aluminum wire. How to connect aluminum and copper wires to avoid problems with electrical wiring will be discussed later in this review.

What is the difficulty of connecting copper and aluminum wiring directly

As is known, the cause of problems in the direct connection of copper and aluminum is electrocorrosion processes. In a dry environment, nothing will happen even with direct contact, but with increased humidity, a short-circuited galvanic cell is formed at the junction, in which the metals begin to play the role of a battery with a “plus” and a “minus”. The metal itself practically melts, resulting in a network rupture with a possible short circuit and insulation fire. Which in turn can lead to a fire.

In order to avoid this, various types of contact devices are used to indirectly connect copper and aluminum wiring.

All connection methods can be divided into 2 groups based on the presence of wire contact:

1. There is direct contact between the wires: twisting, crimping, connection with rivets, strips.
2. There is no direct contact between the wires: threaded fixation, connection with various types of terminal blocks.

Important! To connect aluminum and copper wires, it is recommended to use methods from the second group. It is allowed to use connections from group 1 provided that the copper wire is processed. For example, it can be tinned with solder.

Twist

The main method of connecting wires at home, it is quite convenient in that it does not require special tools and equipment. But in the case of connecting aluminum and copper wires, this method must be used extremely carefully, observing the following conditions:

• A twisted connection is made by mutually twisting both ends of the wire with each other; wrapping the end of one wire around the other is not allowed;
• It is recommended to tin the copper cable with tin or solder before twisting; this point is especially important for stranded copper wire;
• A protective moisture-resistant coating must be applied to the connection between aluminum and copper wires.

There are three main types of twist: simple, bandage and groove twist. It should be noted that bandage twisting will give the best results. When performing twisting, it is worth considering that the number of turns directly depends on the diameter of the wiring, so for a wire up to 1 mm in diameter it is necessary to make at least 5 turns, for large sections at least three turns. In addition to moisture insulation, do not forget about the electrical insulation of the twist; for this you can use special tips.

High-quality twisting will last quite a long time, but only the use of an indirect connection can provide a true guarantee.

How to make a twist correctly

First you need to prepare the ends of the wires. To do this, remove the insulation at a distance of 3–5 cm from the edge of the cable. It should be noted that the heat-shrink tube is placed on one of the wires, before twisting, upon completion of all operations, the tube is moved to an open place and fixed there. After cleaning the ends, you need to twist the wires according to the proposed diagram. In this case, it is necessary to ensure that the cores are wrapped around each other, and that one cable core does not overlap another.

To make it easier to twist a multi-core copper cable, its cores can and should be tinned. It should also be noted that tinning copper in any case increases the reliability of the twisted connection. After twisting, the connection point must be coated with moisture-resistant varnish. Electrical insulation can be accomplished using heat shrink tubing or cap caps with a soft clamp or cone spring.

Insulation of wire ends with caps with a cone spring

Important! Unless absolutely necessary, it is not recommended to use twisting to connect copper and aluminum cables. Currently, there are many safer and more reliable ways to combine copper and aluminum into one network.

In this case, a metal or plastic sleeve or tip is placed on the twisted connection, which is fixed to the connection with press pliers, a special crimping tool. Fixation in this case is carried out by crimping the connection with the sleeve material. The sleeves are a metal tube with insulation made of PVC materials. The nozzles are usually plastic caps into which the compound is inserted, after which the cap is crimped with press jaws.

Separately, it is necessary to note the connection using cap attachments with a clamping ring or cone spring. In this case, after twisting the wires, a cap is put on the twist, after which it is screwed onto the connection using rotational movements, after which it is simply crimped with pliers. In this case, a soft metal ring inside the cap tightly compresses the junction. This crimping option is quite accessible for household use.

Threaded fixation

A reliable, although somewhat cumbersome, way of connecting copper and aluminum wiring is a threaded connection; in this case, the cores are clamped with a nut on a threaded base. In order to avoid direct contact, a washer is placed between the exposed ends of the cores.

The advantages of this connection method are simplicity and versatility. In this way, you can connect several electrical wires of different cross-sections. But at the same time, this type of connection is quite cumbersome, and it is also very inconvenient to isolate. But, at the same time, this type of connection requires only a bolt and nut.

First of all, the ends of the wire are prepared. The insulation is removed at a distance of 1–1.5 cm from the cut, after which rings with a diameter slightly larger than the diameter of the bolt or rivet are made from the exposed wires. These rings are used to attach the wire to the rivet or threaded part of the bolt. A spring washer is placed between the aluminum and copper cable; this is necessary to ensure that there is no direct contact between these metals. After which the connection is fixed by tightening the nut or a riveter.

It is worth noting that this option is suitable for splicing wires of sufficient length; when saving length, which is often found when connecting lighting electrical equipment to the short ends of an aluminum wire, as is often the case in old apartments, it is better to use terminal boxes.

Connecting copper and aluminum wires with rivets

The clamping of the wires in this case is carried out by a wedged rivet, consisting of a tube and a core, fixed with a rivet gun. To connect, prepared conductors with wound rings are placed on a rivet tube with a gasket - a steel washer. After which the rivet is crimped with a rivet tool, the core wedges the rivet tube, thereby compressing the metal cores among themselves, thereby fixing the cable cores.

The contact in this case is permanent, but at the same time strong and reliable. For this type of connection, you need a special tool - a riveter, and skills to work with it. This method is used mainly for working with wire breaks and splicing wire ends in hard-to-reach places.

Connection with two steel strips

You can connect copper and aluminum wires in this tricky way, which also requires pre-treatment of the copper wire with tinning: clamp the wires with two steel strips with bolts at the edges. Advantages of the method: the ability to connect several branches of wiring at once, without increasing the length of the bolt. In this case, the bare ends of the cores are placed between the slats. The method is applicable for wires of the same cross-section.

Important! The connection with two steel strips requires mandatory external insulation, as well as preparation of the copper wire by tinning.

Terminal blocks and terminal boxes

Convenient and reliable connection method. The terminal block is a strip of insulating material in which sockets for wires are located. The wires are fixed in the sockets using clamping bolts. An important feature in our case is the absence of contact between the wires. To connect copper and aluminum wires, you only need a screwdriver.

The terminal box is a system of several separately located terminal blocks, combined into one structure and having several terminals.

The advantages of this connection method are:

• Easy to install, all you need is an electrician's knife to strip the ends of the wire and a screwdriver to tighten the screws;
• Reliability of insulation, very often when using a terminal block or terminal box, additional insulation is not required;
• Undemanding on the length of the wire; 1–2 cm of wire is enough to fix the wire in the terminal box.

At the same time, to install hidden wiring in the wall, the terminal block requires the installation of a distribution box. Without a distribution box, installation of hidden wiring is unacceptable. But in this case, you can use a terminal box for flush mounting.

When working with the terminal box, it is important to carefully fix the ends of the wire in the socket, especially for aluminum wires. This is especially important when installing the box outdoors or indoors where temperature fluctuations are possible.

Connection with spring and self-clamping terminal blocks

Currently, both reusable and single-use terminal blocks and terminal blocks are produced.

• spring terminal blocks and reusable terminal blocks have a retaining spring that can be loosened by lifting a lever located on the device body. This allows you to remove or insert the wire without any effort. Lowering the lever securely fixes the cable cores;
• Single-use terminal blocks automatically clamp the wire when inserting it into the socket; removing the wire will require physical force, which can damage the clamping spring, so their single use is recommended.

Both reusable and single-use terminal blocks are produced in a wide range, including with a different number of connected wiring branches, designed to fix wires with a cross-section from 0.08 mm² to 6 mm². Including in the form of ready-to-install terminal boxes. This method of connecting aluminum and copper wires is currently the most optimal in terms of reliability and ease of use.

Section of the spring terminal block and placement of the connection in the junction box

Terminal boxes with spring clamps were first produced by the German company Wago, from which they got their name, but currently there are a large number of analogues, including counterfeit ones. For this reason, it is necessary to purchase spring terminal boxes only from electrical stores. When purchasing terminal boxes on the market, there is a high probability of purchasing low-quality products that do not meet the stated requirements.

To fix the wires in the terminal box, it is necessary to prepare the wires; to do this, remove the insulation from their ends; the size of the exposed part must be at least 0.5 cm. After that, the open part of the cable core is inserted into the desired socket of the terminal box and fixed in it using a spring clamp or screw. It should be noted that mounting in a terminal box usually does not require additional insulation, but at the same time, when they are located in a wall, a distribution box is required. Thus, spring terminal blocks have a number of advantages over other types of connections due to ease of connection.

Conclusions

In this way, it is quite possible to connect copper and aluminum wire, but it is necessary to take into account the location of the cable and the environment. Copper and aluminum can only be connected by twisting in a dry room. If the humidity in the room increases, this connection may become unusable and, moreover, cause a fire. The most optimal method today is to connect electrical wiring using spring terminal blocks.

The main advantage of this method is stable fixation in any environmental conditions. Despite all the advantages of a screw terminal block, threaded or rivet connection, when operating under conditions of sudden temperature changes, the contact under the screw may weaken. Due to the difference in temperature expansion of the metals of the wires. These changes may result in loss of contact or short circuit. Thus, with all the variety of methods for connecting copper and aluminum wiring, the safest method at the moment is the use of self-clamping terminal blocks.

Video on the topic

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 has a gray or white tint.

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 these materials, when connected, 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 point in saving 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 takes place 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 material capabilities.

Almost everyone already knows that aluminum wiring is a legacy of the last century, and it must be changed when renovating an apartment. Few people carry out major repairs and forget about it.

However, there are situations when the repair is carried out partially, and there is an urgent need to connect an aluminum wire with a copper one or simply extend them by adding a few extra centimeters of wire.

Electrochemical corrosion

However, aluminum and copper are not galvanically compatible. If you connect them directly, it will be something like a mini battery.

When current passes through such a connection, even with minimal humidity, an electrolytic chemical reaction occurs. Problems will definitely show themselves sooner or later.

Oxidation, weakening of the contact, its further heating with melting of the insulation. Transition to a short circuit or burnout of the core.

What such contact can ultimately lead to, look at the photo.

How to make such a connection competently and reliably to avoid problems in the future.

Here are some common methods that electricians use. True, not all of them are convenient for working in installation boxes.

Let's take a closer look at each of them and choose the most reliable one, which does not require subsequent maintenance or revisions.

Connection via bolt and steel washers

Here a steel washer and bolt are used for connection. This is one of the most proven and simple methods. The truth is that it turns out to be a very large design.

For installation, twist the ends of the wires into rings. Next, select the washers.

They must be of such a diameter that the entire eye of the wire is hidden behind them and cannot contact another conductor.

The most important thing is how to position the ring. It must be put on so that when tightening the nut, the eye does not unfold, but rather is pulled inward.

Steel washers between conductors made of different materials prevent oxidation processes. In this case, do not forget about installing the engraver or spring washer.

Without it, contact will weaken over time.

The fact is that metals whose electrochemical potential of the connection does not exceed 0.6 mV can be safely connected to each other.

Here is a table of such potentials.

As you can see, copper and zinc have as much as 0.85 mV here! This connection is even worse than direct contact between aluminum and copper conductors (0.65 mV). This means the connection will not be reliable.

However, despite the simplicity of the threaded assembly, the end result is a large, awkward structure, shaped like a beehive.

And it’s not always possible to stuff this whole thing into a shallow socket. Moreover, even in such a simple design, many manage to screw it up.

The consequences will not keep you waiting in a very short time.

Squeeze - nut

Another method is to use a nut-type connecting clamp.

It is often used to branch off a supply cable with a much larger cross-section than a tap.

Moreover, it does not even require cutting the main wire. It is enough to remove the top layer of insulation from it. Some have found a use for it to connect the input cable to the SIP.

However, you shouldn't do this. Why, read the article below.

But again, nuts are not suitable for junction boxes. Moreover, sometimes such clamps burn out. Here is a real review from a user on one of the forums:

Wago Clamps

There are a series of special clamps that can be used to join copper to aluminum.

Inside these terminals there is antioxidant paste.

However, disputes about the 100% reliability of such clamps, especially for sockets and not lighting groups, have not subsided to this day. When installed in a limited space, the contact may weaken, which will inevitably lead to burnout.

Moreover, this can happen even at a load below the minimum for which Vagos are designed. Why and when does this happen?

The fact is that when the connected conductors are compressed, a small gap appears between the pressure plate and the contact point. Hence all the heating problems.

Here is a very clear video that explains this problem without further ado.

Terminal block

This method has one significant disadvantage. Most of the pads sold are of very low quality.

Some people get clever and, in order to avoid direct contact between copper and aluminum, the copper core is soldered to the side of such a clamp, rather than inserted inside.

True, the terminal will have to be disassembled for this. In addition, reliable aluminum contact under the screw without revision does not last very long.

The screws will need to be tightened every six months to a year. The frequency of revision work will directly depend on the load and its fluctuations during periods of maximum and minimum.

Forget to tighten up and expect trouble. And if this entire connection is hidden deep in the socket, then getting into it every time is not a very convenient task.

Therefore, the most reliable method available is crimping. Here we will not consider the use of specialized copper-aluminum sleeves GAM, since they start from sections of 16mm2.

For home wiring, as a rule, you need to increase the wires by 1.5-2.5 mm2 no more.

Connecting copper and aluminum by crimping

Let's consider the most common case that occurs in panel houses. Let's say you need to power one or more additional outlets from an existing aluminum outlet in a through niche.

For extensions, take a FLEXIBLE copper wire with a cross section of 2.5 mm2. This will reduce the mechanical impact on the aluminum core when you lay the wires in the socket box.

For soldering, it is convenient to use a homemade crucible, which is a slightly modified soldering iron in the shape of a hatchet.

In this case, before soldering with flux, remove the oxide layer from the core.

The tinning process itself involves dipping the wire into a special hole in the soldering iron filled with tin.

After the core has cooled, the remaining flux is removed with a solvent.

Next, move on to the aluminum wires sticking out of the wall. Carefully clean their ends and also remove the oxide layer.

To do this, you can use oxide conductive paste. The same paste is used when installing modular pin grounding systems.

It is designed to work in any conditions and eliminates the further appearance of oxide on the surface of the wire. Keep in mind that the oxide film can subsequently have a resistance several times greater than the aluminum itself.

And without removing it, all your further work will go down the drain. Moreover, the melting point of such a film reaches 2000 degrees (versus approximately 600C for Al).

After all the preparatory work, insert the wires into the GML sleeve from both sides. All that remains is to crimp this connection.

Some people will have a logical question: will the solder layer on the core be pressed through during crimping? Then it turns out that all tinning manipulations will be in vain.

The main thing here is to choose the correct cross-section of the sleeve and die of the tool for crimping.

In this case, the soft solder will, as it were, seal the contact spot of the copper-aluminum connection. And without oxygen access to this point, contact erosion will not be observed.

Be careful; when working with aluminum conductors, you must act with extreme caution, as this is a very brittle material. One careless movement and you are guaranteed to have a broken wire.

After crimping, it is necessary to insulate this connection with adhesive heat shrink.

It is the adhesive type that will ensure 100% tightness and prevent the flow of oxygen to the contact areas. In order not to risk burning the insulation, it is better to heat the heat shrink with a hair dryer rather than with a lighter or portable torch.

The resulting bundle of wires must be placed in the electrical box with great care, since aluminum does not like sharp bends.

Since the extended copper wires are flexible, you put insulated NShVI lugs on the ends of these conductors.

Only after this can they be safely inserted into the terminal blocks of the sockets and the screws tightened.

Of course, this is not the only way to extend aluminum wires, but it is one of the simplest (as opposed to welding or soldering) and reliable (as opposed to twisting).

If you have the slightest opportunity to change the entire aluminum wiring, be sure to do it, do not skimp on your safety.

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 at 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.

Material: aluminum.

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, 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. The 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 powers 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 materials needed to complete the task are purchased. 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 the walls must be chipped. 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.