How to safely connect copper and aluminum wire. How to correctly connect copper and aluminum wire - options and accessories. Connecting aluminum wiring

Modern electrical wiring in an apartment or house is performed only with copper wires, so the PUE says. But in old houses, the wiring was most often done with aluminum wire and a situation arises in which it is necessary to connect 2 wires from different material... 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

To begin with, is it possible to connect aluminum wires with copper ones, and such a connection will not lead to a fire? The answer is yes, you can. But let's take a look at these materials first.

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

Looking at the electrical performance of metals, there is no question of what conducts current better. Here are some details:

• Specific resistance: copper - 0.017 Ohm · mm² / m, aluminum - 0.028 Ohm · mm² / m.
• Heat capacity: copper - 0.385 J / gK, aluminum - 0.9 J / gK.
• The 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 pair.

Galvanic pair - 2 different types of metals, 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, therefore, rapid corrosion will increase the resistance at the junction and then heat it up. For more details on the compatibility of metals, see GOST 9.005-72. Below is a table with some data on metals:

Galvanic compatibility of meltals

It is possible to achieve high-quality contact of two conductors in different ways (soldering, using a simple terminal block, more expensive WAGO terminals or an ordinary bolt and nut).

Wire connection

The connection of aluminum and copper wires to each other requires technological solutions, simple twisting is not enough here.

Ways to connect conductors with different electrochemical potentials:

• By soldering. But not simple soldering.
• Using simple terminal blocks or expensive WAGO. It is not worth saving 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 a lot of advantages: low cost, simplicity and the ability to work with wires of large cross-section.
• Crimping sleeves. A specialized tool is required.

WAGO

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

1. Push the pressure plates to the side with a click.
2. Insert wires into the holes.
3. Put the plates in their places, clamp.

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

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

Twisting wires

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

A couple of tips before doing twisting:

• Before twisting, the copper wire should be well tinned.
• The amount of twisting must be at least 5 turns.
• After work, the joint should 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 a special flux is needed to solder aluminum. Some electricians simply solder the copper wire to the terminal block.

Flux for aluminum

Terminal blocks

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

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

Bolted connection

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

To connect two wires, you will need: a bolt, a nut, 3 washers. Sequencing:

1. At the ends of the wires, make rings of the same diameter as the bolt. For convenience, it is better to use round nose pliers.
2. Put the rings on the bolt in such 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 connections of aluminum and copper

Connection "nut"

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

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

The nut connection is suitable for all types of street connections and branches

Crimping

For this method, you need special crimping pliers and sleeves. The principle of connecting the wires with a sleeve is very simple: on one side, an aluminum wire is inserted into the sleeve, on the other, a copper one, 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 is required. The only drawback of crimping is the high cost of the tool.

Special sleeve for connecting aluminum and copper

Grease

To improve the quality of contact, you can use a special grease or paste. Usually it is quartz-vaseline paste. Usually it is used to improve the connection of aluminum wires.

But such a 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 influenced by additional factors, significantly reducing the durability of the connection. Although the use of grease without insulation is questionable.

Outcome

Based on the foregoing, choose the method that suits you, depending on the connection point (street, house) and material capabilities.

Reading time ≈ 3 minutes

Wiring is never complete without wiring. The higher the electricity consumption in everyday life grows, the more important is the correct connection of the wiring wires, which would ensure the requirements for electrical and fire safety. The correct connection of the wires is the level of contact density, as well as the electrochemical compatibility of the metals of the wires being connected.

Today, many apartments still have aluminum wiring. As soon as such an apartment appears simple task to replace the chandelier or socket, there may be a problem connections of aluminum and copper wires.

It is known that direct connection of these metals is strictly prohibited and is a flagrant violation. Direct contact of copper and aluminum is unacceptable due to the incompatibility of these metals. Under the influence of moisture, such a connection becomes unsafe: it can cause a fire.

Dry contact, although a little more reliable, is also unsafe: it will just break down more slowly. If moisture suddenly gets on such a contact, an accident may occur even with a small current.

How to connect aluminum and copper wires in such a situation?

There are several ways, here are the main ones according to the PUE:

1. Using terminal clamps
2. By threaded connection
3. Using a layer of neutral material
4. Using welding

Perhaps the most in a simple way will use a layer of neutral material. The neutral metal is lead-tin solder.

It's very easy to do

• With a stationery knife, carefully cut and remove the insulation from the wires by about 6-7 cm. Do not place the knife perpendicularly, this way you can cut the wire core. It is better to do this at an angle, like you sharpen a pencil.
• Using a soldering iron, cover the copper wire with solder. To do this, we collect solder on the tip of the soldering iron and dip it in rosin. After the rosin has melted, very quickly run the sting along the wire.
• Make sure the copper wire is well tinned. The solder should completely cover the wire.
• We twist tinned copper and aluminum wires. A good twist should result in about 4 cm.

The method is good because it does not require clamps, or if the bolted connection does not fit into the box.

Despite the fact that the method is simple and quick, nevertheless, if the cumbersomeness of the connection is not a problem, it is better to use a threaded connection, it will be more reliable. Threaded connection of copper and aluminum wires is also quite simple. For this type of connection, you need to prepare a spring washer, three simple washers and a nut. If the conductors have a core diameter of up to 2 mm, choose the M4 screw.

• Remove the insulation for about four screw diameters.
• We clean the metal to a shine and form the rings.
• We put a spring washer on the screw, then a simple washer, then a ring of one conductor, a simple washer, a ring of the second conductor, a washer, a nut.
• We tighten the screw and tighten everything until the spring washer straightens and squeeze another half a turn.

If the copper wire is stranded, you must first wire it. Do not forget that such connections must be checked periodically: the optimal frequency is once a year.

When partial replacement wiring, lengthening the conductor, or replacing the burnt area using a wire. It happens that in their material they do not coincide. Then it becomes necessary to connect aluminum wires with copper ones. There are five ways to do this, and each has its own advantages and disadvantages. Some of them require preliminary preparation of the guide.

Danger of poor wire connection

The industry produces two types of wires for household purposes, copper and aluminum. The first ones have less resistance, which allows using a smaller section with the same load. They are more resistant to mechanical stress, this makes it possible to twist repeatedly, not to be afraid that they will break at the notch. The latter have one advantage - comparative cheapness. But she sometimes plays a key role. What can happen if the connection is of poor quality?

Copper and aluminum have different characteristics , for example, different coefficient of expansion when heated. When a large current passes through an aluminum conductor, it begins to "flow". If the cores move relative to each other during heating or cooling, this will lead to a gap between them. The gap, in turn, will lead to discharge (sparking). Sparks can cause fire. Along with this, copper and aluminum begin to oxidize, the resistance between them increases, the voltage due to this drops or may completely disappear. Power surges can adversely affect the connected devices.

Methods for joining copper to aluminum

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

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

Twisting wires

It is strictly forbidden to use twisting in fire-hazardous premises.... This is the fastest and easiest way. Two or more wires are taken and wrapped relative to each other. Do not leave one or more of one core straight. There is a rule - thick conductors must have at least three turns, thin ones (from 1 mm or less) - five. To reduce the oxidation of the conductor, the copper core is soldered for the length of the twist. The same rule applies to stranded copper cables.

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

Threaded method

More time consuming than twisting connection. Requires a tool and some skill. Has greater mechanical strength. On the electrical side, it is better than twisting. Allows you to immediately connect a large number of wires, and of different cross-sections. You can connect both single-core and multi-core.

A bolt is used for the connection, on which the conductors are put in turn... They are pre-stripped and wrapped in rings. Each core, if made of different materials, is laid with a washer. A washer and a spring washer are applied to the last conductor. The entire package is tightened with a nut until the spring washer is straightened. Further squeezing can break the conductor.

To prevent the washer from cutting the wires, they must be put on in a checkerboard pattern (so that they do not lie on top of each other). If the copper wire is irradiated, no washers are needed. A stranded copper wire also needs to be soldered, then it will not disintegrate when compressed.

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

Terminal method

The terminal connection is manufactured in factories. Has an extensive assortment. Two groups can be distinguished:

• pads;
• terminal blocks.

Pads have different shapes and designs. The bottom line is to attach several wires to one conductor (plate, square, etc.), which are inserted into special connectors and pressed with a screw. Typically, the pads themselves are attached to the base, creating rigidity.

The advantage of the pads is that no preliminary steps are needed, with the exception of stripping the veins. The connection is fast and requires no skills. They are irreplaceable if the conductor is short (connecting a chandelier, restoring a broken wire). If they are located in distribution boards, metering boards, they do not require isolation. Since each wire is connected separately, both copper and aluminum wires can be used.

The disadvantages include the following:

• less resistant to mechanical stress than a threaded connection;
• each block is designed for a conductor of a certain section;
• you cannot connect wires of large and small diameter at the same time;
• take up more space than previous versions.

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

• reusable;
• for single use.

Reusable the terminal strip is a fully insulated block. Instead of screws, a spring plate is used, which is squeezed out using a plastic lever. Then a wire is inserted into the opening. In some embodiments, the plate is serrated to allow the use of bare wires. To remove the wire, you must lift the lever again.

One-time have the same principle, but do not have a lever. Designed for single use. If the wire is pulled out and reinserted, the connection quality will be poor.

Benefits:

• allows you to very quickly connect aluminum and copper wires to each other;
• minimal training required;
• ease of use;
• there is a ready-made necessary insulation.

Disadvantages:

• the most sensitive method to mechanical stress;
• in comparison with other compounds, it is the most expensive;
• sensitive to high currents and, according to user comments, cannot withstand the regulated load.

One-piece method

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

• riveting;
• soldering.

Riveting very similar to a threaded connection, with the only difference that a rivet is used instead of a bolt. The ends of the wires are cleaned of insulation and cleaned with sandpaper. With a combination of aluminum and copper wires, the latter is tinned. This also applies to copper stranded wire. After that, rings are made of a slightly larger diameter than the rivet. Finally, when the entire structure is assembled (without intermediate washers), a washer is put on top. All this is squeezed by the terminal block. Insulated in the same way as threaded.

Soldering used where high reliability and low resistance are required. It looks like a twist, but the wires are soldered. This cannot be achieved in the usual way for aluminum, therefore the wires must be prepared.

This will require a solution copper sulfate, a small non-metallic container, a constant voltage source of 9-24 V. Pour a solution of copper sulfate into the container and lower the pre-cleaned conductors to the length of the twist. We connect the copper wire to "+" so that the electrons go from it, and the aluminum wire to "-". We turn on the power supply.

The voltage, of course, can be increased, the main thing is that the solution does not boil or there is no overload in electrical circuit... You can also reduce the stress, then the process will proceed more slowly. All this works as long as the aluminum wire is not covered with a copper film.

Then both wires are covered with a layer of tin. Twisting is done in 3 turns for a thick wire and 5 for a thin one (less than 1 mm). All this is carefully soldered. It remains to cover them with waterproof varnish, insulate - and the connection is ready.

Benefits:

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

Disadvantages:

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

Now, knowing all the ways to connect copper and aluminum wires without soldering, you should be able to fix this problem when it appears.

Any cable consists of aluminum or copper conductors. By the rules 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 the aluminum and copper wire. There are many such opportunities. All that remains is to choose an affordable 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 modern technologies you can find dozens of conjugations of metal pairs.

There is a concept of electrochemical potential difference, the indicators of which are summarized in a special look-up table. From it, if necessary, take indicators and are determined with compatibility:

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

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

In the absence of moisture, the reliability of the contact is undeniable. But there is no ideal setting. Humidity of the atmosphere always negatively affects the quality of compounds. Any conductor has a certain electrochemical potential. This property is used in practice in the operation of storage batteries.

Getting on the contacting 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 binder of aluminum and copper, it equals 0.65 mV, which makes such a combination unacceptable. However, there are ways to correctly interconnect differing wires.

Twisting cable connection

Most famous, but an unreliable technique 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 drops and precipitation:

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

This method will not work for secure communication. Although if you perform certain operations, in some cases you can apply twisting to connect the aluminum and copper wires:

Threaded wire connection

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

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

Procedure:

1. Cut the insulating cover to the required length for fastening.
2. Sand and degrease the cleaned areas. Insulate multi-wire cable. Connect the cores with a thread 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 bolt, there are also undeniable advantages:

• The wires are connected in random order.
• There is no need to make connecting rings and donning terminals.
• Design features terminal blocks do not allow shorting of wires.
• Insulation of the contact point is not required.
• The work of connecting the terminal contacts is simple.

The ends of the wires are stripped approximately five millimeters, inserted into the clamp and pulled. This method is irreplaceable when connecting aluminum cables, the conductors of which break from multiple bends.

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

Of the many connecting devices not the last place are occupied by the German spring terminal blocks Vago of the same name company. They are both disposable and with a clip for repeatedly splicing 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 made of any metals 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 easiest devices to use. The wire is stripped and inserted with force into the block. The fixation is reliable. It is possible to reach the wire with a well applied force. The spring block is then destroyed and re-use is not possible, which is the biggest disadvantage 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 complete wear and tear.

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. The connection is locked.

Vago terminal blocks are effective adaptations for work on the 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 rivet are used as a fastening element. The rivet is a hollow aluminum rod, thickened on one side. It fits a wire pin with a hat. When passing through the cavity, it creates a thickening on one side. Then the hairpin breaks offforming a rivet.

If you do not take into account the price of the rivet, this method of contact becomes the most accessible, apart from twisting. The disadvantage of such a contact is one-time use and the impossibility of disconnection in case of erroneous work.

The use of special copper sleeves will be another way of permanently connecting conductors. They are produced different sizes, for each section of the cable its own. Bare ends of wires are threaded into them and crimped with special pliers. This method is the most compact on a par with twisting.

Soldering wire connection

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

To neutralize it, you will have to make a simple device. The tip of the aluminum wire is cleaned and processed with a solution of copper sulfate. A battery is taken and this conductor is attached to it minus. The copper wire is fixed on the plus with one end, and with the other it is dipped into the same solution. After a certain period of time, the aluminum will be covered with a copper coating and will become available for soldering.

Specificity of connections for outdoor installation

Outdoor electrical connections are subject to various weather conditions. Insulation requirements are more stringent. To prevent short circuits, a nut clamping set is used.

Its plastic sheath contains metal clamps, in which the wires are connected by tightening the screws. The body halves are tightly compressed with screws or snap rings. Such a cocoon guarantees protection from external weather fluctuations. This is a fairly 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 requires connecting conductors. In order for the connection of wires to be reliable and safe, it is necessary to know the characteristics of each of them, where and when, under what conditions they can be used.

Existing ways of connecting conductors

To connect wires can be done in several ways:

• welding is the most reliable way to ensure high reliability connections, but requiring skills and the presence of a welding machine;
• terminal blocks are a simple feasible and fairly reliable connection;
• soldering - works well if the currents do not exceed the standard and the connection does not heat up to temperatures above normal (65 ° C);
• crimping with sleeves - requires knowledge of technology, special pliers, but the connection is reliable;
• the use of spring clips - wago, PPE - are quickly installed, provided that the operating conditions are observed, they provide good contact;
• bolted connection - simple to perform, usually used in difficult cases - when 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 that will 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 the wires are connected by welding, the conductors are twisted, and their end is welded. The result is a metal ball, which ensures a stable and very reliable connection in all 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 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 amount of wires is left - in case of possible rework.

Other disadvantages include a welding machine, appropriate electrodes, flux and work skill. In addition, welding takes a lot of time, it is required to protect the surrounding objects, and it is also inconvenient to work with the welder at a height. Therefore, electricians practice this type of connection in exceptional cases. If you do "for yourself" and know how to handle well welding machine, you can practice on scraps. The main 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 wire connection

For crimping wires, a special aluminum or copper sleeve is required - it is selected based on the size of the twist (diameter of the bundle), and the material is taken the same as for the conductors. Bare and shine-stripped wires are twisted, a sleeve tube is put on them, which is clamped with special pliers.

Both sleeves and pincers are different, there are several types. Each of them has its own rules of use (the number of wires that can be packed in a sleeve), in which you need to navigate well. It is necessary to pack the wires according to certain rules, measure the size of the resulting bundle, and adjust it to the requirements. In general, a rather dreary task. Therefore, this type of wire connection is mainly used by professional electricians, and more and more often they are switching to spring clamps.

Terminal blocks

One of the simplest and most reliable wire connections is through terminal blocks. There are several types of them, but a screw connection is used almost everywhere. Eat with nests different sizes - for different sizes of conductors, with a different number of pairs - from 2 to 20 and 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, you need to tug the conductor well - make sure that it is tightly clamped. Due to the fact that the connection points remain uninsulated, the area of \u200b\u200bapplication of the terminal blocks is in rooms with normal humidity.

The disadvantage of such a connection: due to the plasticity of metals - especially aluminum - 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, periodically, the wiring in screw terminal boxes must be tightened.

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

Soldering

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

Then, in fact, the soldering process begins: the joint is heated with a soldering iron or a narrow-torch torch. When the rosin or flux begins to boil, they take some of the solder on the tip of the soldering iron, bring it into the soldering zone, pressing the tip to the conductors. The solder flows to fill the gaps between the wires, ensuring a good connection. When using a torch, the solder is simply added a little to the torch.

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

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 laying electrical wiring in a house or apartment, it is criticized mercilessly. The thing is that the solder has a low melting point. With periodic passage of large currents through the connection (it happens if the protective devices 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 found, it may well end in fire.

The second negative point is the low mechanical strength of the soldering. It's about tin again - it's 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 is too great, which pulls them out. Therefore, it is not recommended to use the connection of conductors by soldering when wiring electricity: it is inconvenient, long and risky.

Spring clips for connecting wires

One of the most controversial ways to connect wires is with spring clips. There are several types, but the most common two are wago (wago) terminal blocks and PPE caps. Externally and in the way of installation, they are very different, but at the heart of both designs is a spring, which creates strong contact with the wire.

About this spring and there are disputes. Opponents of wago use say that the spring will weaken over time, the contact will get worse, the connection will start to get hotter, which, again, leads to an even faster decrease in the degree of spring elasticity. After some time, the temperature may rise so much that the body (plastic) will melt, but what can happen next is known.

Spring loaded wiring clamps - popular wire connection

In defense of using spring clips to connect wires, it can be said that if they are used in accordance with the manufacturer's recommendations, problems are very, very rare. Although there are many fakes and wago, and PPE, as well as an abundance of photos of them in molten form. But, at the same time, many people use them, and, under normal operating conditions, they work for years without complaints.

Wago wire clips

They appeared on our market several years ago and made a lot of noise: with their help, the connection is very fast and easy, and at the same time has high reliability. The manufacturer has specific recommendations for the use of these products:

There is a metal plate inside these devices, which ensures the proper degree of contact. The shape and its parameters of the plates were developed and tested specially. The tests were carried out on a vibration stand for many hours, then heated and cooled. Then the electrical parameters of the connection were checked. All tests were passed with "excellent" and branded products always show themselves "five".

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

Detachable

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

Wago wire connectors - connection methods

If necessary, you can reseal 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 stiff wires. The maximum section is 2.5 mm 2. Soft stranded wires can be connected with a cross section of 0.08 mm 2 to 4 mm 2.

One-piece

There is another type of clamps that does not provide for the possibility of remaking the wire connection - series 773 and 273. When using these terminals, the work is generally a second: the stripped wire is inserted into the corresponding socket. There is a spring clamping it, ensuring 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 of \u200b\u200b0.75 mm 2 to 2.5 mm 2, stranded with rigid wires from 1.5 mm 2 to 2.5 mm 2. Soft stranded conductors cannot be connected with these connectors.

To improve contact, the wires must be cleaned of oxide film before connecting. To prevent further oxidation from continuing, wago manufacturers also produce contact paste. The inside of the clamp is filled with it and it itself corrodes the oxide film, and then protects the wires from oxidation in the future. In this case, only highly oxidized, dark conductors need preliminary stripping, 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, 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.

Clamps for lamps (construction and installation terminals for lamps)

For quick and convenient connection of lamps or sconces, wago has special 224 series terminals. With their help, it is possible to connect aluminum or copper wires of different cross-sections and types (single-core or stranded with rigid wires). The nominal voltage of this connection is 400 V, nominal current:

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

Cross-section of the connected conductors from the mounting side:

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

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

When connecting copper wires, contact paste must be used, and aluminum wires must be manually stripped to bare metal.

This product has two drawbacks. First, the price for original terminals is high. 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 clamps”) are very easy to use devices. It is a plastic body with a conical spring inside. 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, they are available in different sizes, for different diameters and the number of conductors to be connected. In order for the wire connection to be reliable, the size must be selected correctly, and for this it is necessary to understand the marking.

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

All other numbers 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 conventional, conical. It can be used to connect two conductors with a cross-section of at least 0.5 mm 2 (they add up to 1 mm, which meets the minimum requirements - see the table). This cap contains maximum conductors, the total cross-section of which should not exceed 4 mm 2.

Connection of wires with PPE caps

In the second version of the marking, after the abbreviation PPE, 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, PPE caps can only connect copper wires - 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 is assembled quickly and easily, it serves for a long time and reliably.

First, the conductors are stripped of insulation, if necessary, the upper oxidized layer is removed. Further, a loop is formed from the stripped 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 tighten ( middle variant in the right figure). After that, all this is collected in this order:

• A washer is put on the bolt.
• One of the guides.
• The second washer.
• Another conductor.
• Third puck.
• Nut.

The connection is tightened first with your hands, then with keys (you can take pliers). That's all, the connection is ready. It is mainly used 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 gets very hot, which in itself is very bad.
• Over time, contact weakens. This is because aluminum has a lower electrical conductivity than copper, as a result, when passing the same currents, it heats up more. When heated, it expands more strongly, 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 conductors of different diameters are to be connected, no twisting should be present to obtain good contact. This means that you can use the following types:

• terminal blocks;
• wago;
• bolted connection.