Connecting aluminum and copper wires: consider ways to connect wires to each other. How to connect aluminum and copper wires Is it possible to connect copper to aluminum

When installing electrical wiring, it is quite often necessary to connect different current conductors, namely, aluminum and copper wires. From the point of view of electrical and fire safety, this type of connection is more risky and must be carried out 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 connecting aluminum and copper wires

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

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

Indicators of a reliable wire connection:

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

The first requirement of high-quality electrical wiring is quite simple to fulfill. The second requirement is often ignored in practice and incompatible current conductors are connected in a direct way (twisting). It is 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 the aluminum wire in contact with moisture has a high resistance. This negatively affects the electrical conductivity of the connections.

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

In a pair, copper and aluminum form a short-circuited galvanic connection - when moisture enters the contact, the aluminum wire begins to actively oxidize. A thin film with high resistance is formed between the current conductors, as a result, the current conduction becomes difficult, the electrolysis process takes place, shells, heating, and sparking of the contacts form at the contact point. This situation may cause a fire.

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

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

The main methods of connecting different current conductors

application of terminal blocks

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

In essence, a terminal block is an insulating plate with contacts. Fastening wires in the terminal block is of two types:

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

Among the advantages of the "terminal" method of connecting wires include:

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

The sequence of connecting copper electrical wires with aluminum:

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

The terminal block, before being hidden under the finish, must be placed in a junction box

spring terminals for connecting wires

One of the varieties of terminal blocks are Wago spring clamp blocks.

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 clip 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 wire, it is better to use special Wago terminal blocks. 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.

Spring terminal blocks are of two types:

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

connection through the "nut"

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

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

The principle of operation of the riveter is simple - retraction and subsequent cutting of the rod, which passes through the tubular rivet with a cap.

The wire connection technology is as follows:

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

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 there are no special adapters or a riveter at hand, you can use alternative methods for connecting different conductors.

Bolted connection 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:

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

A technologically more complex and time-consuming method is applying solder to a copper wire. You can use lead-tin solder.

When aluminum comes into contact with lead-tin solder, the electrochemical resistance index is 0.40 mV (the permissible rate is not more than 0.60 mV)

The wire connection sequence 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 an electrical wire with significant loads, such a connection cannot be used.

Features of connecting wires indoors and outdoors

Outdoor wire connections are exposed to external factors and need additional protection.

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

In addition, branch clamps nuts are also suitable for the street.

To connect the wires in the 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 for connecting aluminum and copper wires, which had very sad consequences. These methods include:

1. Stranding copper and aluminum wire. It should be noted that a number of experts do not recognize twisting, even if a layer of solder is applied to the copper wire.
2. Twisting of wires with subsequent protection of the junction from moisture. As a waterproofing, some "craftsmen" use paraffin, oil or varnish. This method is unacceptable and, to put it mildly, ineffective.

To date, 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 test untested methods, endangering the safety of not only housing, but also the people living in it.

Today, there are many ways to connect wires in a junction box.

Here are some factors that determine the choice of connector:

1. Core material (copper or aluminium).
2. Working conditions (outdoors, in an apartment, in water, in the ground, in the floor, normal conditions).
3. Number of conductors (two, three, four, etc.).
4. The cross section of the veins (the same, different).
5. Core structure (single-wire or multi-wire).

Based on these factors, the most appropriate and correct method is selected. To begin with, consider the materials with which you can connect electrical wires in a junction box.

Existing methods

The following connection options are considered the most popular and effective:

• use of terminal blocks;
• installation of spring terminals (wago);
• fixation with PPE (plastic caps);
• sleeve crimping;
• soldering;
• twist;
• installation of "nuts";
• use of bolts.

Consider the essence, advantages and disadvantages of each method!

Installing PPE caps

PPE stands for connecting insulating clamps. Products are ordinary plastic caps with a special spring inside, which holds the wires.

Most often, such caps are used to connect cores in junction boxes.

Benefits of using these products:

• low cost of PPE;
• the caps are made of non-combustible material, so there will be no twisting at the place;
• fast installation;
• caps have a wide range of color shades. For example, if the wires do not have, you can mark with the help of PPE (using a white, blue and green cap).

Disadvantages:

• relatively poor quality of insulation and fixation;
• it is impossible to combine aluminum with copper.

Crimping with special sleeves

Twisting and insulation

The old "grandfather" method consists in twisting the cores together. The essence of the work is that the conductors are stripped and carefully twisted with pliers, after which the place of twisting is isolated.

Advantages:

• ease of electrical work;
• no material costs.

Disadvantages:

• poor quality of fastening lived;
• connection of aluminum and copper products is unacceptable.

We figured out the existing methods of connecting wires in the box, now we will consider the remaining, important issues of this topic.

What if there are several wires?

When bonding two contacts, problems usually do not arise. But what if you need to combine three, four or more at the same time?

• using wago terminal blocks;
• sleeve crimping;
• soldering;
• twisting using sizov;
• twisting and winding with electrical tape.

The order of connecting the wires for each of the methods we discussed in detail above. We strongly recommend that you use the first option, because. it is one of the most modern and efficient. At the same time, the cost of the vag is not too high, and the wiring has been serving for more than 30 years.

What to do if the conductors are of different sections?

To connect conductors of different cross-sections in a junction box, it is recommended to use all the same terminal blocks of the car, or a cheaper option - ordinary terminal blocks. In this case, it is necessary to carefully tighten the wires with a screw or fix with a flag, and that's all, the work is over.

Please note that if the wires are made of different materials, then it is necessary to use special pads with paste inside, which will prevent the wires from oxidizing. These pads include wago products.

Also, conductors of different sections can be fixed by soldering.

Combining stranded and solid wires

Connecting single-core and stranded wires separately does not have any features, so you can use any of the methods listed above.

In order to carry out bonding, it is necessary to choose one of two options: car terminals or soldering. It all depends on your preference, the advantages and disadvantages of each method we have provided.

How to work in water and land

During electrical work, a situation often occurs when it is necessary to fasten electrical wiring under water or in the ground. Now we will briefly consider the features of each of the cases!

In water (for example, when installing a submersible pump), it is recommended to use the following technology. To begin with, the ends are soldered, after which the soldering point is carefully insulated with hot-melt adhesive, over which it is put on. If everything is done efficiently and conscientiously, the joint will be tight and safe. Otherwise, power outage may also occur.

To connect an electrical wire in the ground (for example, after it has been mechanically damaged), it is recommended to use the method provided above (hot glue and heat shrink), but it is better to protect yourself and use the following method. Clamp the ends of the cable with a terminal block, install a sealed junction box, and then carefully fill the box with a special silicone sealant. We draw your attention to the fact that the underground track must be additionally placed in a pipe or box in order to ensure reliable!

Any cable consists of aluminum or copper conductors. The rules for the installation of electrical installations, the usual twisting of such wires is strictly prohibited. But there are situations during installation when there are no options other than how to connect aluminum and copper wire. There are many such possibilities. It remains only to choose an affordable and safe one.

Electrochemical destruction of metals

The opinion about the impossibility of combining 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 pairs of metal pairs.

There is the concept of the difference in electrochemical potentials, the indicators of which are summarized in a special reference table. From it, if necessary, take 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.

In order to imagine what is happening, it is necessary to understand the reactions that electrodes of various metals enter into when they come into contact.

In the absence of moisture, the reliability of contact is undeniable. But there is no ideal environment. The humidity of the atmosphere always has a negative effect on the quality of the joints. Any conductor has a certain electrochemical potential. This property is used in practice in the operation of batteries.

Getting on the contact planes from various compounds, water creates a short-circuited galvanized medium. One electrical conductor begins to deform. The material from which it is made is also subject to destruction.

Methods for connecting wires from different metals

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

Cable connection by twisting

most famous, but an unreliable reception is called twisting. This method does not require special skills and is easy to manufacture. 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.
• Cable oxidation, contact destruction.

To ensure a secure relationship, this method is not suitable. Although if you perform certain operations, in some cases you can use twisting to connect aluminum and copper wires:

Threaded wire connection

A similar method is performed by clamping the ends of the cable into a bolted fastener. This is the most reliable connection of aluminum and copper wires to each other. 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 section.
• Multiwire and monolithic.
• With washers to prevent direct contact with copper and aluminum conductors.

Procedure:

1. Cut off the insulating coating to the length required for fasteners.
2. Sand and degrease cleaned areas. Irrigate multi-wire cable. Connect the cores with a thread through steel washers.
3. Tighten the nut firmly.
4. Shock absorbers are placed in front of the outer washers to prevent pinching and breaking of the wire. When crimped, it straightens and the connection is 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 bolt one, there are also undeniable advantages:

• The wires are connected randomly.
• There is no need to make connecting rings and put on tips.
• The design features of the terminal blocks do not allow wires to short circuit.
• Contact isolation is not required.
• The work on connecting the terminal contacts is simple.

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

Repair of damaged cables using terminal blocks is also the only acceptable one due to the short length of the wires. After splicing, a junction box is mounted.

Of the numerous connecting devices, not the last place is occupied by the German spring terminal blocks Vago of the company of the same name. They are both disposable and with a clip for repeated splicing of the wire. Such terminal blocks are used when working with single-wire wires with a cross section of one and a half to two and a half squares from any metals in insulating boxes. According to the passport, they are designed for twenty-four amperes in terms of load. Contacts are treated with a special composition to prevent oxidation.

These are the easiest devices to use. The wire is stripped and forcefully inserted into the block. The fixation is secure. It is possible to get the wire with a well-applied effort. The spring block is destroyed and reuse is impossible, which is the biggest drawback of this product.

Reusable terminal blocks Wago with an orange lever are designed for the use of wires of any type with a cross-sectional area of ​​\u200b\u200bup to four square millimeters and currents 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 about ten millimeters, the lever rises, 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 fastener. The rivet is a hollow aluminum rod thickened on one side. A wire pin with a hat 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, apart from twisting. The disadvantage of such contact is the one-time use and the impossibility of separation if the work is done by mistake.

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

Connecting wires by soldering

If there is a desire, then dissimilar wires can be soldered. This method must take into account certain technological features. Before the wires are properly connected, aluminum and copper must be prepared for soldering. Copper does not require special tricks. Another thing is aluminum wire. On its surface, under the influence of ambient air, an oxide film is formed - an amalgam. 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 cleaned and treated with a solution of copper sulfate. A battery is taken and its minus is attached to this conductor. The copper wire is fixed on the plus at one end, and the other is dipped into the same solution. After a certain period of time, 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. In order to prevent shorting, a Nut clamping kit is used.

In its plastic shell there are metal clamps in which the wires are connected by tightening the screws. The body halves are tightly compressed with screws or spring rings. Such a cocoon guarantees protection from external weather fluctuations. This is a rather large-sized connection, but in outdoor conditions this is not critical.

When wiring or repairing electrical wiring, when connecting household appliances and a lot of other work, it is required to connect conductors. In order for the connection of wires to be reliable and safe, it is necessary to know the features of each of them, where and when, under what conditions they can be used.

Existing methods of connecting conductors

To connect the wires can be done in several ways:

• welding is the most reliable method, providing high reliability of the connection, but requiring skills and the presence of a welding machine;
• terminal blocks - a simple and fairly reliable connection;
• soldering - works well if the currents do not exceed the normative ones and the connection does not heat up to temperatures above the norm (65 ° C);
• crimping with sleeves - requires knowledge of technology, special pliers, but the connection is reliable;
• the use of spring clips - wago, PPE - quickly installed, subject to operating conditions provide good contact;
• bolted connection - easy to perform, usually used in difficult cases - if it is necessary to switch from aluminum to copper and vice versa.

The specific type of connection is selected based on many factors. It is necessary to take into account the material of the conductor, its cross section, the number of cores, the type of insulation, the number of conductors to be connected, as well as the operating conditions. Based on these factors, we will consider each of the types of connections.

Welding – high reliability in all conditions

When connecting wires by welding, the conductors are twisted, and their end is welded. As a result, a ball of metal is formed, which provides a stable and very reliable connection under any conditions. Moreover, it is reliable not only in terms of electrical characteristics, but also mechanically too - the metal of the connected wires after melting forms a monolith and it is impossible to isolate a separate conductor.

Welding - it is important to heat the metal, but not to melt the insulation

The disadvantage of this type of wire connection is that the connection is 100% one-piece. If you need to change something, you need to cut off the fused piece and redo it all over again. Therefore, for such connections, a certain margin of wires is left - in case of a possible alteration.

Other disadvantages include a welding machine, appropriate electrodes, flux and work skills. In addition, welding takes a lot of time, it is necessary to protect surrounding objects, and it is also inconvenient to work with a welder at a height. Therefore, electricians practice this type of connection in exceptional cases. If you are doing “for yourself” and know how to handle a welding machine well, you can practice on scraps. The trick is not to melt the insulation, but to weld the metal.

After cooling, the welding site is isolated. You can use electrical tape, you can use heat shrink tubing.

Crimping connection of wires

For crimping wires, a special aluminum or copper sleeve is required - it is selected based on the size of the twist (beam diameter), and the material is taken the same as that of the conductors. The wires that are bare and cleaned to a shine are twisted, a tube-sleeve is put on them, which is clamped with special tongs.

Both sleeves and pliers are different, there are several types. Each of them has its own rules of use (the number of wires that can be packed into a sleeve), in which you need to be well versed. It is necessary to pack the wires according to certain rules, measure the size of the resulting bundle, and adjust it to the requirements. All in all, a pretty tedious job. Therefore, this type of wire connection is mainly used by professional electricians, and even more often they switch to spring clips.

Terminal blocks

One of the simplest and most reliable wire connections is through terminal blocks. There are several types, but almost everywhere a screw connection is used. There are sockets of different sizes - for different sizes of conductors, with a different number of pairs - from 2 to 20 or more.

The terminal block itself is a plastic case in which a metal socket or plate is soldered. A bare conductor is inserted into this socket or between the plates, clamped with a screw. After the screw is tightened, it is necessary to pull the conductor well - make sure that it is well clamped. Due to the fact that the connection points remain uninsulated, the scope of the terminal blocks is rooms with normal humidity.

The disadvantage of this connection is that due to the plasticity of metals - especially aluminum - the contact weakens over time, which can lead to an increase in the degree of heating and acceleration of oxidation, and this again leads to a decrease in contact. In general, the connection of wires in screw terminal boxes must be tightened periodically.

Advantages - speed, simplicity, low cost, does not require any skills, except perhaps the ability to use a screwdriver. Another important advantage is that you can easily connect wires of different diameters, single-core and stranded, copper and aluminum. There is no direct contact, therefore there are no risks.

Soldering

First, about soldering technology. The connected conductors are cleaned of insulation, cleaned of oxide film to bare metal, twisted, then tinned. To do this, the conductors are heated with a soldering iron, applied to rosin. It should cover the junction completely. Tinned wires are twisted first with fingers, then squeezed using pliers. Soldering flux can be used instead of tinning. They wet the wires well, but after twisting.

Then, in fact, the soldering process begins: the junction is heated with a soldering iron or a narrow-torch burner. When the rosin or flux begins to boil, take some of the solder on the soldering iron tip, bring it into the soldering area, pressing the tip against the conductors. The solder spreads out, filling the gaps between the wires, making a good connection. When using a torch, the solder is simply added little by little to the torch.

Further, after the soldering place has cooled down, according to the technology, it is necessary to wash off the flux residues (they accelerate oxidation), dry the joint, cover it with a special protective varnish, and then insulate it with electrical tape and / or heat shrink tubing.

Now about the advantages and disadvantages of this method of connecting wires. In low-current systems, soldering is one of the most reliable ways to connect wires. But, when wiring electrical wiring in a house or apartment, it is criticized mercilessly. The thing is that the solder has a low melting point. With the periodic passage of high currents through the connection (it happens if the circuit breakers are incorrectly selected or faulty), the solder gradually melts and evaporates. Time after time, the contact gets worse, the connection heats up more and more. If this process is not detected, it may well end in a fire.

The second negative point is the low mechanical strength of soldering. The point is again in tin - it is soft. If there are a lot of wires in a soldered joint, and if they are still rigid, when trying to pack them, the conductors often fall out of the solder - the elastic force that pulls them out is too great. Therefore, the connection of conductors by soldering when distributing electricity is not recommended for use: it is inconvenient, long and risky.

Spring terminals for connecting wires

One of the most controversial ways to connect wires is with spring clamps. There are several types, but the most common two are wago terminal blocks and PPE caps. Externally and by the method of installation, they are very different, but both designs are based on a spring that creates a strong contact with the wire.

There is controversy about this spring. Opponents of using wago say that the spring will weaken over time, the contact will become worse, the connection will start to heat up more and more, which, again, leads to an even faster decrease in the degree of elasticity of the spring. After some time, the temperature may rise so much that the case (plastic) will melt, but what can happen next is known.

Spring clips for electrical wiring - popular wire connection

In defense of the use of spring clamps for connecting wires, if they are used in accordance with the manufacturer's recommendations, problems are very, very rare. Although there are many fakes of both wago and PPE, as well as an abundance of pictures of them in a melted form. But, at the same time, many use them, and, under normal operating conditions, they work for years without any complaints.

Clips for wires wago

They appeared on our market a few years ago and made a lot of noise: with their help, the connection is very fast and easy, while it has high reliability. The manufacturer has specific recommendations for the use of this product:

Inside these devices there is a metal plate, which provides the proper degree of contact. The shape and its parameters of the plates were developed and tested specifically. The tests were carried out on a vibration stand for many hours, then heated-cooled. After that, the electrical parameters of the connection were checked. All tests were passed as "excellent" and branded products always show themselves as "five".

In general, the Wago product range is very wide, but for wiring or connecting household appliances, lighting fixtures, two types of wire clamps are used: the 222 series (detachable) with the ability to remake or change the connection and the 773 and 273 series - which are called one-piece.

Detachable

Spring clamps for electrical wiring Wago 222 series has a certain number of contact pads - from two to five - and the same number of flags-clamps. Before starting the connection, the flags are raised up, the conductors stripped of insulation are inserted into them (up to the stop), after which the flag is lowered. At this point, the connection is considered complete.

wago wire connectors - connection methods

If necessary, you can remake the connection - raise the locking flag and remove the conductor. Convenient, fast and reliable.

The 222 vago series can be used to connect two or three, even five conductors made of copper or aluminum (you can connect different metals in one terminal). Wires can be solid or stranded, but with rigid wires. The maximum section is 2.5 mm 2. Soft stranded wires can be connected with a cross section from 0.08 mm 2 to 4 mm 2.

One-piece

There is another type of clamps that does not provide for the possibility of redoing the connection of wires - the 773 and 273 series. When using these terminals, the work is generally seconds: the stripped wire is inserted into the appropriate socket. The spring present there clamps it, providing contact with the plate. Everything.

These spring-loaded wire clamps can be used to connect solid aluminum or copper wires with a cross-sectional area from 0.75 mm2 to 2.5 mm2, stranded wires with rigid wires from 1.5 mm2 to 2.5 mm2. Soft stranded conductors cannot be connected using such connectors.

To improve contact, before connecting the wires, it is necessary to clean the oxide film. To prevent further oxidation, wago manufacturers also produce contact paste. It fills the inside of the clamp and it itself corrodes the oxide film, and then protects the wires from further oxidation. In this case, only highly oxidized, dark conductors need to be pre-stripped, and the clamp body is filled with paste.

By the way, manufacturers say that, if desired, the wire can be pulled out of the clamp. To do this, they take the wire with one hand, hold the terminal box with the other and rotate them back and forth with a small range, in opposite directions, stretching in different directions.

Clips for lamps (construction and installation terminals for lamps)

For quick and convenient connection of lamps or sconces, wago has special terminals of the 224 series. With their help, you can connect aluminum or copper wires of different sections and types (solid or stranded with rigid wires). Rated voltage of this connection is 400 V, rated current:

• for copper conductors - 24 A
• 16 A for aluminum.

Cross-section of connected conductors on the mounting side:

• copper 1.0 ÷ 2.5 mm2 - single-core;
• aluminum 2.5 mm2 - single-core.

Cross-section of connected conductors from the chandelier/sconce side: copper 0.5 ÷ 2.5 mm2 - single-core, stranded, tin-plated, crimped.

When connecting copper wires, the use of contact paste is mandatory, and aluminum wires must be manually stripped to bare metal.

This product has two drawbacks. First, the price of original terminals is high. The second - there are a lot of fakes at a lower price, but their quality is much lower and it is they who burn and melt. Therefore, despite the high cost, it is better to buy original products.

PPE caps

PPE caps (stands for "connecting insulating clips") are very easy to use devices. This is a plastic case, inside of which there is a spring that has a conical shape. Conductors stripped of insulation are inserted into the cap, the cap is scrolled clockwise several times. You will feel that it has stopped scrolling, which means the connection is ready.

How to make a wire connection using PPE

These conductor connectors are produced by many manufacturers, there are different sizes, for different diameters and the number of connected conductors. In order for the wire connection to be reliable, the size must be selected correctly, and for this it is necessary to understand the markings.

After the letters of the PPE comes a few numbers. Depending on the manufacturer, the number of digits varies, but they mean the same thing. For example, there is this type of marking: PPE-1 1.5-3.5 or PPE-2 4.5-12. In this case, the number immediately following the letters indicates the case type. "1" is set if the body is an ordinary cone, on the surface of which grooves can be applied - for a better grip. If there is a PPE-2, then there are small protrusions on the case, which are convenient to take with your fingers and twist.

All other figures reflect the total cross section of all conductors that can be connected using this particular PPE cap.

For example, PPE-1 2.0-4.0. This means that the body of the connecting cap is ordinary, cone-shaped. With it, you can connect two conductors with a cross section of at least 0.5 mm 2 (in total they give 1 mm, which corresponds to the minimum requirements - see table). Maximum conductors are included in this cap, the total cross section of which should not exceed 4 mm 2.

Connecting wires using PPE caps

In the second marking option, after the PPE abbreviation, there is only a number from 1 to 5. In this case, you just need to remember which one is useful for which wire section. The data is in another table.

PPE caps and their parameters

By the way, only copper wires can be connected with PPE caps - aluminum conductors, as a rule, are thicker than the maximum allowable for these connectors.

Bolted connection

This connection is assembled from a bolt of any diameter, a suitable nut and one, or better three, washers. It assembles quickly and easily, serves quite a long time and is reliable.

First, the conductors are stripped of insulation, if necessary, the upper oxidized layer is removed. Further, a loop is formed from the cleaned part, the inner diameter of which is equal to the diameter of the bolt. To make it easier, you can wrap the wire around the bolt and twist it (the middle option in the right picture). After all this is assembled in this order:

• A washer is put on the bolt.
• One of the conductors.
• Second puck.
• Another conductor.
• Third puck.
• Screw.

The connection is tightened first by hand, then with the help of keys (you can take pliers). That's all, the connection is ready. It is used mainly if it is necessary to make a connection of wires from copper and aluminum, it can also be used when connecting conductors of different diameters.

How to connect aluminum and copper conductors

By the way, let us recall why it is impossible to directly connect copper and aluminum wires. There are two reasons:

• Such a connection is very hot, which in itself is very bad.
• Over time, contact weakens. This is because aluminum has a lower electrical conductivity than copper, and as a result, when the same currents are passed, it heats up more. When heated, it expands more, squeezing out the copper conductor - the connection gets worse, it heats up more and more.

To avoid such troubles, copper and aluminum conductors are connected using:

• terminal blocks;
• wago;
• bolted connection;
• branch clamps (make wire connections on the street).

Other types of connectors cannot be used.

How to connect wires of different diameters

If it is necessary to connect conductors having different diameters, twisting must not be present to obtain good contact. So you can use the following types:

• terminal blocks;
• wago;
• bolted connection.

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

What problems can arise when joining aluminum and copper

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

1. Decreased electrical conductivity. Aluminum is an active metal, under normal conditions it is covered with an oxide film with low conductive qualities. Copper does not have this property.
2. Weakening of contacts. Due to the formation of plaque, contacts become worse. Such a film does not form on copper conductors, therefore metals are considered electrochemically incompatible.
3. Fire hazard. When wondering how to connect an aluminum wire to a copper one, they remember that electrical contact occurs between the oxide deposits formed on the wires. Over time, metals begin to heat up, which leads to a fire.
4. Electrolysis. If the system is operated in conditions of high humidity, the connection begins to break down, becoming a source of fire. First of all, corrosion covers the aluminum parts of the wiring. With regular heating and cooling, cracks appear in the insulating braid, the connection is covered with an oxide or salt layer, which accelerates destruction.
5. The formation of conductive soot. Contact in this case is broken, a fire starts in the house. When operating electrical wiring in a dry room, this process lasts for years. With high humidity, ignition occurs after a few months.

Ways to connect different wires

How to connect copper and aluminum wires:

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

In the second case, special compounds are used that can protect the metal from the effects of moisture and oxidation. Pastes prevent the destruction of the connection. Another way to protect against fire is tinning. Tinned stranded cable can be twisted with aluminum single core. For connection, special devices are also used:

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

Terminal blocks

Terminal blocks are:

1. Disposable. They are used when connecting wires in junction boxes and installing chandeliers. To insert the cores into the hole of the device, efforts must be made. Even more difficult is the extraction of the cable from the block.
2. Reusable. For fixing there is a lever, thanks to which the cable can be inserted and removed several times. Blocks of this type are used when connecting stranded wires from different metals. If the work is not done correctly, the connection can be redone.

Installation is carried out as follows:

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

Crimping

In this case, tubular sleeves are used, which reliably and safely fasten the wiring elements. To connect the cables, you will need a press, mechanical, hydraulic or electric pliers. Installation includes:

• sleeve selection and tool adjustment;
• cleaning the wires from the braid;
• stripping the cores (sandpaper is used for this);
• applying a quartz-vaseline composition;
• inserting the ends of the cables into the rivet;
• crimping (when using a simple tool, several crimps are performed at a short distance, when using a good tool, crimping is performed once);
• connection isolation.

The wires are inserted into the sleeve from opposite sides so that the joint is located in the middle of the connector. Cores can be inserted from one side. The connection of cables with a sleeve is sometimes replaced by the use of “nut” clamps, however, the latter are less reliable. The rivet will loosen over time, increasing the risk of fire.

Bolted connection

Subject to the installation rules, the method provides a durable fastening. To complete the work, you will need 2 simple washers, 1 spring washer, nut and bolt. The wires are cleaned of insulating material. A spring washer is put on a bolt, which is inserted into a simple washer. The end of the aluminum cable is folded into a ring, which is thrown onto the bolt. After that, put on a simple washer and screw on the nut. The stranded wire is coated with solder before starting work.

Soldering

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

Features of the connection lived on the street

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