How to combine copper with aluminum. How to properly connect copper and aluminum wires? Why you can't connect copper and aluminum directly

Modern electrical wiring in an apartment or house it 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 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 technical specifications copper, the cross-section of aluminum wire under the same conditions has to be taken larger. There are also disadvantages: copper is more expensive. Distinguish copper wire aluminum is lighter in 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 these materials, when connected, create a galvanic couple.

Galvanic pair - 2 metals various 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 here.

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 wires large section.
Crimping with sleeves. Requires specialized tools.

WAGO

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

Click the pressure plates to the side.
Insert wires into holes.
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 possibility quick recovery energy 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 connection point must be protected with several layers of insulating tape or heat shrink tube.

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

List of tools and Supplies Electrical 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. Sequencing:

Make rings at the ends of the wires, the same diameter as the bolt. For convenience, it is better to use round nose pliers.
Place the rings on the bolt in such an order that they are between the three washers.
Tighten the nut and check the quality of the connection.
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 use "nut" simply as 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.

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

What happens when dissimilar metals join

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

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

Methods for properly connecting aluminum and copper electrical conductors

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

twisting with tinning of a copper core;

threaded
block
one-piece
spring clamps (Wago)

Tinned copper wire

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

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

Threaded connection

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

The conductors are exposed to a length four times the diameter of the screw. They clean off oxides and form rings into which the screw will be inserted. In a certain sequence they wear:

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

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

Terminal block connection

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

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

Pads with clamps

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

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

Permanent connections

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

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

Methods for connecting copper and aluminum wires (video)

It would seem that what could be simpler than connecting wires? After all, there are several ways to connect wires. This includes twisting wires, soldering wires, welding wires, crimping and connecting wires using a terminal block. Even a schoolboy knows the easiest way to twist conductors. You need to put the ends of the metal wires, called strands, together and twist them into one “pigtail”, and then wrap them with electrical tape. There is no need for a soldering iron, terminal block, connecting caps and other “unnecessaries”.
Any “own electrician” has mastered this operation. And, when the need arises, he applies this method in his daily practice. For example, splices wires power cord household appliance, tablet or computer adapter after a break.
Russian “technicians” use this technology for fastening wires everywhere. It’s just that the rules for constructing electrical installations of PES do not provide for “twisting”, all kinds of “bends” and “rivets”. There are no such methods of electrical installation in other regulatory documents. Why?

We often don’t think about the consequences of such a “simplification”. Meanwhile, an unreliable contact will fail at the most inopportune moment; the power supply to consumers/power receivers can always be cut off. Voltage “surges” cause breakdown of the elements of the power cascades of complex SBT household appliances. They don’t even save you from breakdown special devices protection used in the most sophisticated models of foreign manufacturers.

The induction of short electromagnetic pulses with a voltage of several thousand volts onto the electronic filling causes “harmless” sparking at the joints. At the same time, the standard protection equipment that apartments are now equipped with (RCD, circuit breakers, fuses) such short low-current pulses are not “seen”, so they simply do not trigger, and we do not customarily install special devices for this. Sources uninterruptible power supply Computers also did not become a panacea for transient impulses. The occurrence of “poke” causes malfunctions in the operation of electronic equipment and computer equipment, leading to failure of electrical components and expensive functional modules.
Overheating at the site of a poor connection leads to even more catastrophic consequences; when current passes, the weakened connecting node becomes red-hot. This often causes fires and fires, causing enormous damage to the owners of the premises. Statistics show that 90% of all electrical wiring faults occur due to twists and poor contact connections of conductors. In turn, the malfunction itself electrical wiring and equipment, according to the Ministry of Emergency Situations, is the cause of one third of the fires occurring in Russia.

However, historically it happened that several decades ago, in conditions of shortage of electrical accessories/copper conductors, twisting of aluminum wires was considered the main method used in electrical installation work. Twisting as a connection can be used in electrical engineering when carrying out repair and restoration work.

How to connect wires correctly

How to connect the wires: we start by removing the insulation. Correct connection conductors must satisfy three basic requirements:

Ensure reliable contact with a minimum transition resistance between each other close to the resistance whole piece wires.
Maintain tensile strength, fracture resistance and vibration resistance.
Connect only homogeneous metals (copper to copper, aluminum to aluminum).

There are several connection methods that satisfy these requirements. Depending on the wiring requirements and capabilities practical application, the following types of wire connections are used:

All these methods require preliminary preparation wire or cable - stripping the insulation to expose the connected cores. Traditionally, rubber, polystyrene, and fluoroplastic are used as insulating shell materials. Additionally, polyethylene, silk and varnish serve as insulation inside. Depending on the structure of the conductive part, the wire can be single-core or multi-core.
By single-core is meant a wire whose cross-section is formed by an insulating sheath with a metal core or wiring inside.

IN stranded wire the metal core is formed by several thin wires. They are usually intertwined and represent a lay, surrounded on the outside by an insulator. Often, individual wires are coated with polyurethane varnish, and nylon threads are added to the structure between them to increase the strength of the wire. These materials, like the fabric braid on the outside, complicate the process of removing the insulation.

Depending on the type of connection, 0.2–5.0 cm of insulation is removed from each end of the wire. Several types of tools are used for this.
Using a 5-point system, you can evaluate the quality of insulation removal and the degree of protection against cutting - damage to cores by each device:

Damage to insulation/core

Monter (kitchen) knife – 3/3
Side cutters (nippers) - 4/3
Stripper - 5/4
Soldering iron or electric loop burner - 4/4

In low-current television/computer networks, coaxial cables are used. During the cutting process, it is important to carefully cut and remove the insulating jacket without damaging the shielding braid. To access the central vein, it is fluffed up and removed, exposing the trunk. After which the polyethylene insulation is cut with a knife or a special device, the trim is removed from the core.
The bifilar in the screen consists of a pair of wires in the screen, which, in order to access the conductors, is also pre-fluffed into wires, allowing access to each core.

Important! To remove the insulating material of an enameled wire with a cross-section of less than 0.2 mm², a soldering iron should be used. The enamel is carefully removed using sandpaper and moving the paper along the wires.

How to twist wires correctly

Most often, twisting is used in the repair of electrical wiring, cords and adapters (including low-current) household appliances and equipment. If we are talking about the home electrical network, then the standards provide for the use in homes of wires with a current-carrying core cross-section of 1.5–2.0 mm made of copper and 2.5–4.0 mm made of aluminum. Typically, wires of the VVG and PV brands in a polyvinyl chloride sheath are used for wiring. Power cords of the ShVL and ShTB brands with rubber or PVC insulation have a cross-section of 0.5 - 0.75 mm.
You can splice the wires together step by step as follows:

Degrease the bare ends of the wires by wiping with acetone/alcohol.
We remove the varnish layer or oxide film by sanding the conductors with sandpaper.
Apply the ends so that they intersect. We wind clockwise at least 5 turns of one core onto another. To make the twist tight, use pliers.
We insulate the open current-carrying parts of the wires using electrical tape, or screw on an insulating cap. They should extend beyond the insulation for 1.5–2.0 s to cover the exposed areas of the conductors.

To splice a stranded stripped wire with a single-core wire, another winding technique is used:

A single wire is wrapped with a stranded wire, leaving the end free without winding.
The end of the single-core wire is bent 180° so that it presses the twist, then pressed with pliers.
The connection point must be firmly fixed with electrical tape. For best performance, an insulated heat pipe should be used. To do this, a piece of cambric of the required length is pulled over the connection. To make it grip the wiring more tightly, the tube should be heated, for example, with a hair dryer or lighter.

With a bandage connection, the free ends are placed next to each other and wrapped on top with an existing piece of wire (bandage) made of a homogeneous material.
Coupling with a groove provides that before mutual twisting, small hooks are configured from the ends of the wire, they are interconnected, then the edges are wrapped.
There are more complex varieties of parallel/serial connections. Connecting wires using the twisting method is used by professional electrical repairmen when carrying out restoration work.

Important! Copper and aluminum have different ohmic resistances; when they interact, they actively oxidize; due to different hardnesses, the connection turns out to be fragile, so the connection of these metals is undesirable. In case of emergency, the ends to be connected should be prepared - tinned with tin-lead solder (PLS) using a soldering iron.

Why is it better to crimp (crimp) wires?

Wire crimping is one of the most reliable and quality ways mechanical connections currently in use. With this technology, loops of wires and cables are crimped into a connecting sleeve using press pliers, ensuring tight contact along the entire length.

The sleeve is a hollow tube and can be made independently. For liner sizes up to 120 mm², mechanical pliers are used. For large sections, products with a hydraulic punch are used.

When compressed, the sleeve usually takes the shape of a hexagon; sometimes local indentation is made in certain parts of the tube. In crimping, sleeves made of electrical copper GM and aluminum tubes GA are used. This method allows crimping of conductors made of different metals. This is largely facilitated by the treatment of the constituent components with quartz-vaseline lubricant, which prevents subsequent oxidation. For joint use, there are combined aluminum-copper sleeves or tinned copper sleeves GAM and GML. Wire connections using the crimp method are used for conductor bundles with a total cross-sectional diameter between 10 mm² and 3 cm².

Soldering as a reliable alternative to twisting

The closest alternative to twisting, which is prohibited for electrical installation, is to connect wires using the soldering method. It requires special tools and consumables, but provides absolute electrical contact.

Advice! Overlapping wire soldering is considered the most unreliable in technology. During operation, the solder crumbles and the connection opens. Therefore, before soldering, apply a bandage, wrap a piece of wire of a smaller diameter around the parts being connected, or twist the conductors together.

You will need an electric soldering iron with a power of 60–100 W, a stand and tweezers (pliers). The soldering iron tip should be cleaned of scale, sharpened, having first selected the most suitable shape of the tip in the form of a spatula, and the body of the device should be connected to the ground wire. Among the “consumables” you will need POS-40, POS-60 solder from tin and lead, rosin as a flux. You can use solder wire with rosin placed inside the structure.

If you need to solder steel, brass or aluminum, you will need a special soldering acid.

Important! Do not overheat the junction points. To prevent the insulation from melting when soldering, be sure to use a heat sink. To do this, hold the bare wire between the heating point and the insulation with tweezers or needle-nose pliers.

The wires stripped of insulation should be tinned, for which the tips heated with a soldering iron are placed in a piece of rosin; they should be covered with a brown-transparent layer of flux.
We place the tip of the soldering iron tip into the solder, grab a drop of molten solder and evenly process the wires one by one, turning and moving along the tip blade.
Attach or twist the wires together, securing them motionless. Warm up with the tip for 2–5 s. Treat the areas to be soldered with a layer of solder, allowing the drop to spread over the surfaces. Turn over the wires to be connected and repeat the operation on the reverse side.
After cooling, the soldering joints are insulated in the same way as twisting. In some compounds, they are pre-treated with a brush dipped in alcohol and coated with varnish.

Advice! During and after soldering for 5–8 s. The wires cannot be pulled or moved, they must be in a stationary position. A signal that the structure has hardened is when the solder surface acquires a matte tint (it shines in the molten state).

But welding is still preferable

In terms of connection strength and contact quality, welding surpasses all other technologies. IN Lately portable ones appeared welding inverters, which can be transferred to the most inaccessible places. Such devices are easily held on the welder's shoulder using a belt. This allows you to work in hard to reach places, for example, welding from a stepladder in distribution box. For welding metal cores into a holder welding machine carbon pencils or copper-plated electrodes are inserted.

The main disadvantage of welding technology - overheating of the parts being welded and melting of the insulation - is eliminated using:

Correct adjustment of the welding current 70–120 A without overheating (depending on the number of welded wires with a cross-section from 1.5 to 2.0 mm).
The duration of the welding process is no more than 1–2 seconds.
Tightly pre-twist the wires and install a copper heat sink clamp.

When connecting wires by welding, the twisted wires should be bent and the cut side must be turned upward. An electrode is brought to the end of the wires connected to ground and the electric arc is ignited. The molten copper flows down in a ball and covers the twisted wire with a sheath. During the cooling process, an insulating belt made from a piece of cambric or other insulating material is put on the warm structure. As an insulating suitable material also varnished fabric.

Terminal blocks are the most ergonomic electrical installation products

The PUE rules, clause 2.1.21 provide for the type of connections using clamps (screws, bolts). There is a connection directly using hanging fasteners, when a screw and washer are threaded through the loops of each wire and secured with a nut on the reverse side.

This installation is wrapped with several turns of electrical tape and is considered quite practical and reliable.
Electrical installation products called screw terminal blocks are more ergonomic. They represent contact group, placed in a housing made of insulating material (plastic, porcelain). The most common way to connect wires using terminal blocks is in junction boxes and electrical panels. To connect the wire, you need to insert it into the socket and tighten the screw; the clamping bar will securely fasten the wire to seat. Another connecting wire is connected to the mating socket, short-circuited with the first one.

In self-clamping terminal blocks of the WAGO type, the wire snaps into the socket for better contact a special paste or gel is used.

Branch clamps represent a permanent version of a screw terminal block with several short-circuited taps; they are used mainly outdoors and in places with unfavorable environmental conditions.

The connecting clamps are an insulating cap with a thread inside; it is screwed onto the twist, simultaneously compressing and protecting from mechanical stress.

Most often, the need to connect aluminum and copper wires arises in the process of replacing or repairing existing electrical wiring. Also, the ability to do this will be very useful if the power cord of any electrical appliance is damaged.

There are several ways to solve this problem. Check out the presented options, choose the method that is most suitable for your case and get to work, observing the requirements of the technology.

We connect the wires by twisting

An additional advantage of this option is the ability to simultaneously connect several conductors, the number of which is limited only by the length of the screw.

The method is suitable for connecting cables of different diameters and with different numbers lived You just need to make sure that between the wires different materials there was no direct contact. To eliminate this, a spring washer is included in the connection. Additionally, such washers must be installed to prevent contact of the conductors with the nut and screw head.

The order of connecting the conductors is as follows.

First step. We remove the insulation from the cables. We calculate the required length by multiplying the diameter of the screw used by 4.

Second step. We study the condition of the veins. If they have oxidized, we clean the material until it shines, and then form rings according to the diameter of the screw.

Third step. We alternately put a spring washer, a ring of wire, a washer, a ring of the next conductor and finally a nut on our screw. Screw the nut until the washers are straight.

Helpful advice! You can first tin the end of the copper cable with solder. This will eliminate the need to place a spring washer between the conductors.

We make the connection using a terminal block

The method of connecting conductors with special terminal blocks is gaining increasing popularity. In terms of reliability, this option is inferior to the previous one, but it also has its advantages.

Terminals make it possible to connect wires as quickly, simply and efficiently as possible. In this case, there is no need to form rings or insulate connections - the terminals are designed in such a way that the possibility of contact between bare parts of the cables is eliminated.

The connection is made as follows.

First step. We remove the insulation from the connected ends of the wires by about 0.5 cm.

Second step. We insert the cables into the terminal block and secure them with a screw. We tighten it with a little force - aluminum is a fairly soft and brittle metal, so it does not need extra mechanical stress.

Terminal blocks are very often used when connecting lighting fixtures to aluminum wires. Repeated twisting leads to rapid breakage of such conductors, as a result of which practically nothing remains of their length. In such situations, the block comes in handy, because to connect with it, just a centimeter length of cable is enough.

The terminals are also very suitable for connections when laying new wiring is impractical and the remaining length of the conductors is not enough to make connections using other methods.

Important note! The pads can be plastered only if they are installed in a junction box.

Not long on the market electrical equipment and components, modified terminals equipped with spring clamps were presented. Disposable (conductors are inserted without the possibility of their further removal) and reusable (equipped with a lever that allows you to remove and insert cables) terminals are available.

Disposable terminal blocks allow you to connect single-core conductors with a cross-section within the range of 1.5-2.5 mm 2. According to the manufacturers, such terminals can be used to connect cables in systems with currents up to 24 A. However, professional electricians are skeptical about this statement and do not recommend applying loads higher than 10 A to the terminals.

Reusable terminals are equipped with a special lever (usually painted orange) and allow you to connect cables with any number of cores. Allowable conductors to be connected are 0.08-4 mm2. Maximum current – 34A.

To make a connection using these terminals, do the following:

remove 1 cm of insulation from the conductors;
lift the terminal lever up;
insert the wires into the terminal;
lower the lever.

Terminals without levers simply snap into place.

As a result, the cables will be securely fixed in the block. The costs of making such a connection will be more significant, but you will spend much less time on the work and save yourself from the need to use any additional tools.

Making a permanent connection of wires

The main difference between this option and the previously discussed threaded method is the inability to disassemble the connection without destroying the wires. In addition, you will have to buy or rent a special device - a riveter.

Actually, the wires are connected using rivets. Durability, affordable cost, simplicity and high speed of work - these are the main advantages of a permanent connection.

The riveter works on an extremely simple principle: a steel rod is pulled through the rivet and cut. There is some thickening along the length of such a rod. As the rod is pulled through the rivet, the rivet will expand. Rivets of various diameters and lengths are available on the market, which allows you to choose a device for connecting cables of almost any cross-section.

We work in the following order.

First step. We clean the insulating material from the conductors.

Second step. We make rings at the ends of the cables slightly larger than the diameter of the rivet used.

Third step. We alternately place a ring of aluminum wire, a spring washer, then a ring of copper cable and a flat washer onto the rivet.

Fourth step. We insert the steel rod into our rivet gun and forcefully squeeze the handles of the tool until there is a click, which will indicate that the excess length of the steel rod has been trimmed. At this point the connection is ready.

You have become familiar with the basic methods of connecting aluminum and copper wires yourself. Each method has its own characteristics, disadvantages, advantages and preferred areas of application. Choose the most suitable option, follow the instructions and very soon everything will be done necessary connections will be ready.

Good luck!

Prices for cables and wires for construction and repair

Cables and wires for construction and repair

Video - Connecting aluminum and copper wires

When installing electrical wiring, quite often there is a need to connect different current conductors, namely, aluminum and copper wires. From an electrical and fire safety, this type of connection is more risky and must be performed with strict adherence to a number of rules.

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

Difficulties in connecting aluminum and copper wires

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

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

Indicators of reliable wire connection:

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

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

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

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

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

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

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

Basic methods of connecting different current conductors

application of terminal blocks

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

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

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

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

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

Copper connection sequence electrical wires with aluminum:

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

The terminal block must be placed in a junction box before being hidden under the trim.

spring terminals for connecting wires

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

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

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

There are two types of spring terminal blocks:

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

connection via nut

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

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

permanent connection

The permanent connection is made using special tool- riveter.

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

The wire connection technology is as follows:

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

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

Alternative ways to connect aluminum and copper wires

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

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

Bolted connection technology:

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

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

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

The sequence of connecting the wires will be as follows:

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

Features of connecting wires indoors and outdoors

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

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

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

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

Expert advice: how not to connect aluminum and copper wires

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

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

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