How to connect copper and aluminum wire in a junction box

How to connect wires in a junction box

Let's assume that you are a bit of an electrician and decide to install or replace the wiring in your own house or apartment yourself. But if you don’t know any other way than to connect the wires in the junction box using simple twisting, we recommend that you familiarize yourself with this material. After all, there are many methods for reliable joining of contacts: welding, soldering, crimping, as well as the use of electrical connectors. Each of the options must be applied correctly and in the right place.

Soldering and welding of wires

Modern requirements set out in regulatory documents (PUE) prohibit splicing electrical wiring by conventional twisting, regardless of the insulation method. But if the twisted wires are soldered or welded, the contact will be reliable and will comply with all the rules.

Let's look at how to connect current-carrying parts of cables in a junction box using desoldering:

1. Remove the insulation from the wires at a distance of about 3 cm and sand them with fine sandpaper.
2. Twist the strands tightly together using pliers.
3. Using rosin and solder (POS 61 brand is suitable), carefully tin the connection so that molten tin flows into the space between the wires.
4. Insulate the joint with heat shrink tubing or wrap it with adhesive tape.

Note. Soldering copper is not difficult, but oxidized aluminum sometimes has to be treated with acid.

Connecting wires by welding is performed in the same manner, only instead of a soldering iron, a device with a carbon electrode is used. A special recess is made in it, into which flux is poured, after which the device is plugged into the network, and the electrode is pressed against the twist until an influx is formed in the form of a small ball.

The advantage of this method is the durability of the joint and the ability to connect wires of different sections, including multi-core ones, in the junction box. Due to its reliability, the connection is successfully used in power lines with various loads, but it has some disadvantages:

• Do not solder or weld copper conductors with aluminum ones;
• This connection is permanent and in case of alteration according to a new scheme, the contacting areas have to be bitten off.

Reference. Soldering contacts is often used when installing low-current networks, for example, telephone cables and radio points.

Disconnection by crimping method

In this case, the reliability of the connection of the wires in the junction box is ensured using sleeves made of the same metal as the conductors - aluminum or copper. To complete the job, you will also need special press pliers, shown in the photo.

Note. Some would-be electricians practice crimping sleeves with ordinary pliers, which is unacceptable. Correct fixation of contacts is carried out only with pliers.

Now about how to connect electrical wires in a box in this way:

1. Perform termination and twisting of wires as described above.
2. Place a sleeve over the twisted ends (it should be matched to the diameter and fit tightly).
3. Crimp the sleeve with pliers in two places.
4. If the distribution boxes are installed outdoors, the connection is insulated with heat shrink, ensuring tightness. PVC insulating tape can be used indoors.

This joining option has the same pros and cons as welding: you can connect wiring of different sections and numbers of wires, but you cannot connect contacts made of dissimilar metals.

Application of connecting terminal blocks

Terminals for quick connection of wires are of 2 types:

• screw clamps in the form of blocks;
• Wago type self-clamping connectors

The technology for splicing electrical cables using terminal devices is quite simple. The wires need to be exposed only 1 cm and inserted into the clamps. In the first case, the cores are fixed with screws, in the second - with levers or automatic latches. By the way, terminals with latches are disposable, while terminals with levers are used repeatedly.

We list the advantages of screw terminal blocks:

1. Fast and reliable docking.
2. Ability to connect copper wiring to aluminum.
3. Provides a detachable connection.
4. Does not require additional insulation.

One of the disadvantages of the pads is their size. It happens that when there is a large accumulation of wires coming from several switches or sockets, the screw connector does not fit inside the junction box. Point two: single-core wires are fixed without problems, but multi-core wires are flattened with screws, which is not good. Therefore, it is better to pre-tin such ends.

Wago clamps, which allow you to connect up to 4 wires of the same cross-section, have the same advantages as screw terminals, but take up less space. In this case, the operation of disconnecting the entire junction box will take about 5 minutes, which is very convenient for installing electrical wiring. Judge for yourself: the bare end needs to be inserted into the clamp with pliers until it stops and that’s all.

Reference. Similar devices are often used for laying Internet cables and other low-current networks.

Since there are cheap products on the market from various Chinese manufacturers, self-clamping terminal blocks have acquired a dubious reputation.

The fact is that in low-quality connectors, the contact weakens over time, causing them to overheat and melt.

If you purchased original Wago products, then there will be no problems; in other cases, it is better not to take risks and connect only lighting wires with clamps (power supply to switches, chandeliers, and so on). Wire the sockets using a different method.

The master will tell you how to use self-clamping terminals correctly in his video:

Plastic PPE caps

The abbreviation SIZ stands for connecting insulating clamp. It is a cone-shaped cap made of plastic, which contains a steel spring with an anodized coating.

The technology for using the product is as follows:

1. Remove the insulation from the wires to be connected to a distance of 2-3 cm.
2. Gather the wires into one bundle and insert them into the cap until it stops.
3. Applying force from the blind part, turn the cap by hand 2-3 turns. A traditional twist is formed inside, secured with a spring.

Such clamps are quick-release and reusable, provided that the spring was not damaged during dismantling. With their help, the connection in the box is made quite quickly, does not require insulation and does not take up much space.

Important point. In order for the PPE cap to provide reliable and durable contact, it must be selected according to the diameter corresponding to the total cross-section of the wires being connected. For the correct selection, use the table:

Details on how to connect wires in a junction box in various ways, including using caps, are described in the video:

Conclusion

Now, knowing the features of all methods of connecting contacts in a junction box, you can choose the best option and successfully apply it. Finally, let us mention another old method of connecting conductors - bolted, when the conductors are bent around the thread to the right side and pressed with a nut. But this option is practically not used due to the inconvenience and cumbersomeness of the connection, although it is considered reliable and complies with the PUE.

Design engineer with more than 8 years of experience in construction.
Author and editor-in-chief of all articles on the website “qustu.com”. Graduated from the East Ukrainian National University. Vladimir Dal with a degree in Electronics Industry Equipment in 2011.

Source: https://qustu.com/kak-soedinit-provoda-v-raspredelitelnoj-korobke/

Soldering copper wires in a junction box

Absolutely any electrical wiring diagram is accompanied by branches and connections of wires and cables. To do this, you need to purchase a distribution box - it is made of polymer material, looks quite aesthetically pleasing, is located under the ceiling and can have a square or round shape.

1. Why do you need to use a junction box 2. How can you connect the wires in a box - Twisting of wires in a junction box - Crimping of wires - Welding of wires - Soldering of wires - Screw terminals - Bolted connection of wires in a box - Self-clamping terminals

Why use a junction box

Indeed, many novice builders and repairmen ask this question - “packing” wires and their connections/branches is a rather tedious, painstaking and slow task. Agree, it is much easier to twist all the wires in the right places, insert them into the wall and plaster this place. But before making such a decision, you should heed the warnings of experts :

1. There is no free access to the wires. But it may happen that a socket or switch in a room stops working - how can you check where exactly there is no voltage? Open up the entire wall, remove finishing materials, trench the surface? This is definitely not a way out of the situation - the repair will be completely ruined, and everything will have to be redone.
2. There is a need to install an additional socket or another switch. It is inconvenient to connect such devices from already installed and working sockets/switches - it is from the distribution box that you can lay the necessary wires, practically and quickly.
3. Neglecting to install the distribution box means violating regulatory documents. Yes, the PES regulatory document clearly states:

“All connections and branches of wires and cables must always be accessible for inspection and repair.”

1. Compliance with fire safety. The distribution box is one of the conditions for ensuring the fire safety of the premises.

In general, a distribution box is definitely needed, especially since installing it is not difficult even for an absolute beginner in construction and repair work. But the most important step remains - connecting all the wires, and you need to know the types of such connections.

How to connect wires in a box

The connection of the wires must fulfill the task of full and durable contact of all wires - the chain does not break, and there is no risk of a short circuit. And you can ensure the connection at the required level in the following ways :

• welding;
• twist;
• soldering;
• bolted connection;
• crimping with a connecting sleeve;
• use of self-clamping terminals;
• use of screw terminals for contact.

These methods have been tested over the years, each of them can be used, but only in accordance with the rules for carrying out such specific work.

Twisting wires in a junction box

This option is chosen because of the simplicity of the work. After all, it is enough to just strip 10-20 mm of wires from the insulation and twist them with pliers. This is how our ancestors connected wires! But officially such a connection of wires is prohibited - it is sensitive to pulse current, has a high transition resistance, and with use the contact will become worse and then burn out completely.

Please note: you should not connect the wires in the junction box by twisting, although many craftsmen still do this. The fact is that in critical situations (for example, a fire due to a short circuit), all responsibility for what happened falls on the shoulders of the owner of the square meters.

Wire crimping

This method requires purchasing a special connecting sleeve, which can be made of copper (suitable for connecting copper wires) or aluminum (optimal for working with aluminum wires). Pressure testing of the connecting sleeve must be carried out using press pliers.

This method of connecting wires in a junction box is quite reliable; it is included in the group permitted by regulatory documents.

Wire crimping technology:

• the insulating material is removed from the wires to a length equal to the length of the connecting sleeve;
• the wires are twisted into a bundle and inserted directly into the sleeve;
• the sleeve is pressed using press pliers;
• the connection is insulated with insulating tape or heat shrink.

Please note: it is not recommended to carry out crimping using ordinary pliers - the connection of the wires will not be reliable.

Welding wires

This method is considered reliable and safe, since the wires are connected by melting and as a result become one. And such a solid wire will not oxidize, which means that the connection will not weaken, the contact will remain strong.

To carry out such work, you need not only to have welding skills, but also to have the following tool available::

• welding machine (its power must be more than 1 kW);
• protective equipment – ​​glasses (or mask), gloves;
• a small piece of sandpaper - you will need it to strip the wires;
• stationery knife - it is easy to remove insulation from wires;
• electrode (carbon);
• flux - it protects the melt from air.

Wire welding technology:

1. 60-80 mm of insulation is removed from the wires, the exposed wires are thoroughly cleaned with sandpaper - as a result they should shine.
2. The prepared wires are connected to each other by twisting. Make sure that the ends of the wires are at the same level when twisting, and the length of such a connection should be at least 50 mm.
3. Flux is poured into the recess of the prepared electrode.
4. The “ground” of the device is placed on the bare wire, the welding machine is turned on and the electrode is pressed against the top of the wires.
5. The electrode must be held on the wires until a metal ball, called a contact point, forms. As a rule, this process takes 3-5 seconds.
6. The contact point is cleared of flux, and the connection point is insulated.

It is noteworthy that such a connection lasts a long time; in some Khrushchev apartments, such wires have been in use for 50 years or more.

Soldering wires

This connection method is identical to welding, but the wires are secured together using solder. To carry out the work you will need the following tool:

• soldering iron;
• sandpaper (fine);
• rosin (flux);
• tin-lead solder;
• brush - used to apply rosin to the wires.

The work is performed using the same technology as welding:

1. The insulation is removed from the wires, everything is cleaned to a shine.
2. The wires are twisted together.
3. Rosin (flux) is applied to the wires.
4. The soldering iron melts the tin-lead solder - it should flow directly into the twist.

Please note: copper wires are connected to each other using the soldering method, but for aluminum wires you will need to purchase special solder.

Screw terminals

This method is modern, practical and simple. It is with the help of contact clamps that copper and aluminum wires can be connected to each other, although this is not practiced.

To connect wires using screw terminals, you only need to take 2 steps:

• Insulation is removed from the wires - no more than 5 mm;
• the prepared wires are inserted into the clamp and the screw is tightened.

Please note: do not tighten the screw with great force - you can damage the wires, which especially often happens with aluminum wires. If the work is carried out with a stranded wire, then the connection will need to be carefully crimped so that the contact is complete.

Bolted connection of wires in a box

This connection method is reliable, but very cumbersome - it is not suitable for modern distribution boxes, but it is quite suitable for Soviet-style boxes. By the way, in this way you can connect wires from different materials to each other.

  Flux for soldering copper with soft solder

Bolted connection technology:

1. A steel washer is placed on the bolt.
2. The insulating material is removed from the wires, after which you need to form them into a ring.
3. The first ring is put on the bolt.
4. A second steel washer is placed on the bolt immediately behind the wire.
5. The second wire is put on top.
6. The resulting structure is clamped with a nut.
7. All wires/connections are insulated.

If the task is to connect several pairs of wires, then it is better not to use this method.

Self-clamping terminals

You need to buy special terminals - inside they contain a paste that prevents the wires from oxidizing, so absolutely any metal can be inserted into the terminals.

Source: https://rem-serv.com/payka-mednyh-provodov-v-raspredelitelnoy-korobke/

Broken wire in the wall - how to properly connect copper and aluminum - Do It Yourself

Situations when it is necessary to connect or extend wires during the operation of electrical wiring occur in the following cases:

1. If the electrical wiring is cut while drilling or tapping the walls.
2. When moving sockets, switches and lamps without replacing power cables.
3. If the length of the conductor in the installation or junction box after repeated re-wiring is not sufficient to connect it.
4. Breaks in power cords of household appliances.

The correct way out of these situations is to replace the damaged section of electrical wiring or power cord. But as a temporary measure or in cases where replacing a section of wiring is not economically feasible, you can get by with making wire connections.

How to properly connect wires to each other in a wall

If you need to connect damaged electrical wiring in the wall of a panel house, then it is better to replace the damaged area with a new one. The conductors pass inside the cavities allocated for them and are not rigidly fixed.

Both ends of the damaged wire are found and disconnected. Then a new piece of wire is tied to one of them. The temporary connection is made securely and wrapped with electrical tape so that the edges do not cling to irregularities encountered along the way.

Pulling out the old wire, drag a new one in its place.

It is important that the material of the new conductor matches the material of the old one. If the wiring in the apartment is aluminum, then aluminum must also be used for replacement.

Instructions for connecting conductors in the wall

The connection of conductors in the wall is carried out as follows:

1. We determine the direction of laying the damaged area.
2. Turn off the power to the area being repaired.
3. Along the axis of the cable laying, we cut the wallpaper to a length of 20 cm on both sides of the damage site. Use a spatula to remove the wallpaper from the wall and bend it to the sides. This will allow you to stick them back on after the repair.
4. Using a hammer and chisel, we release the cable from the wall on both sides of the damage site by the same 20 cm. You can use a flat, dull screwdriver instead of a chisel. Do not apply strong impacts to avoid damaging the cable insulation.
5. If one of the line conductors is damaged, separate it from the serviceable ones. To do this, we open the cable sheath or cut the flat wire (“noodles”) lengthwise. The core insulation should not be damaged, so be patient, careful and persistent.
6. If all the wires are damaged, we cut the cable in both directions.
7. We cut the cable cores into lengths depending on the chosen connection method. Connection by welding, soldering, crimping or using terminals is allowed.
8. If the cable cores are made of copper, then when using ZVI terminals (also called nylon terminals), you will not need to insert a repair jumper. Having selected a terminal of the appropriate cross-section, use them to connect the ends of the wires.
9. In other cases, you will need to install a repair insert. It uses wires of the same material and cross-section. There are two connections for each wire.
10. Connections require sealing. If the wall is damp, touching it at the location of the uninsulated connection will result in an electric shock. Therefore, the contact point must be tightly wrapped with insulating tape, additionally placing heat-shrinkable or PVC tubes on the wires.
11. We lay the wires in the groove and cover it with plaster. Until the solution has completely dried, voltage cannot be applied to the repaired cable due to the possibility of a short circuit.
12. After the solution has completely dried, we paste the wallpaper back.

Features of conductor connection methods

A reliable connection method is welding . It uses a voltage of 12-36 V from a welding inverter or a homemade transformer. One wire (ground) is connected to the twisted wires, and the other to the carbon electrode. When the electrode touches the top of the twist, an arc occurs. It melts the wires and a metal ball appears at the end of the twist.

The result of connecting wires by welding

While reliable, welding also has a number of disadvantages :

• you will need equipment: a welding machine or a homemade transformer, a carbon electrode;
• difficulties with connecting aluminum conductors: aluminum is welded only in an environment of inert gases that prevent it from oxidizing.

The second most reliable permanent connection is soldering . But soldering aluminum is just as difficult as welding - you need special solder and flux. In air, this metal is covered with a film of oxides that appears instantly. Therefore, the principle of aluminum soldering is to dissolve the oxide and treat the wire in a flux environment.

There will also be difficulties when soldering old stranded wires. Each of their veins is covered with oxide, so before soldering you have to carefully scrape it off with a knife from all sides. It is better to tin it with solder fat; the use of rosin is ineffective.

Before soldering, the wires are thoroughly cleaned of oxides, dirt and soot. They are then twisted together and the resulting joint is tinned.

Solder connection

For crimp , connecting sleeves are used. These are thin-walled tubes of various diameters for connecting conductors of corresponding sections. The sleeves are made of copper or anodized (tinned), the latter are universal and connect copper and aluminum conductors.

The wire is inserted into the sleeve from one side to the middle, then pressed with special pliers or a press. Then another wire is inserted on the other side and pressed in as well. PVC tubes or heat shrink are first placed on the wires to insulate the connection. But fully insulated connection sleeves are also available.

Crimping twists with sleeves

The disadvantage of this method is that it requires a special crimping tool; pliers are not suitable for this.

The use of nylon terminals of the ZVI brand also poses difficulties when connecting aluminum conductors. Aluminum is a soft metal, and the connection in the terminal is made by pressing the wire against the brass surface with the end of a screw.

The tightening force must be commensurate with the plasticity of the conductor, otherwise it can be cut. Flexible conductors are connected to the FVI only after tinning or termination with a sleeve tip (sleeve). But even in this case, you can’t push too hard.

ZVI terminals and their application

There is an opinion that if the conductors are twisted together and a wire connection is installed on top of the twist, the connection is reliable. But the terminal block screws, on the contrary, loosen the twist and worsen the contact.

Therefore, the use of connections using nylon terminal blocks is functionally limited: you can temporarily connect or repair equipment with their help.

Although in modern lamps the connection is made only through the ZVI.

There is only one advantage of the method: it is cheap.

WAGO self-clamping terminals are considered the most versatile means for making contact connections. No shortcomings have yet been discovered. The connection occurs through a spring-loaded contact into which the conductor is inserted. The terminal contains a lubricant that protects the wires from oxidation. If necessary, the connection can be disassembled.

About WAGO terminals, read the article: “Which is better to choose, twisted or terminal block for connecting wires?”

WAGO terminal

Another way to connect wires is with PPE caps (insulated connecting clamp). The cap is screwed onto the twist, tightening it and at the same time insulating it. Lubricant is also placed inside it.

PPE caps

For more information about PPE caps, read “PPE caps for twisting wires. Electrician's advice."

If WAGO terminals are selected according to the cross-section of the wires being connected, then PPE and ZVI are selected according to the diameter of the twist. And since the twists come in different cross-sections, depending on the number of wires in them, installation work requires a set of terminals of different calibers.

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Source: https://cheboksary-otdelka.ru/mebel/perebityj-provod-v-stene-kak-pravilno-soedinit-mednyj-i-alyuminievyj.html

Experience using WAGO terminal block | Don't mix copper and aluminum!

Surely you heard in school (if you went to school at all - like me) about these valences of metals, about their incompatibilities, and perhaps even heard about semiconductors.

So, I’ll tell you - don’t twist copper and aluminum , never at all . Well, if, of course, the load currents do not exceed 0.1 - 1 A, then it is possible, but I do not recommend it. This is what we will talk about next with a practical example.

And now in detail. Perhaps you are an experienced and not very electrician and have decided to buy wires for yourself or someone you know. Then they suddenly remembered that you have the Internet at home, and they probably already figured out how to quickly and without headaches make junction boxes, reliably and for 3 kopecks. And they really came up with it!

Wago or twists?

If earlier, about 15-20-30 years ago, twists were used everywhere. And they still use it now because it’s more reliable. Then progress has long since stepped forward and invented for humanity - Wago TERMINAL BOARDS . Yes, not simple ones for a screwdriver and a nut with a bolt, but major ones - they are called WAGO terminal blocks and they are produced in various types. For soft and hard wire, for 2.5-4 sq.mm and for 6-8 sq.mm with and without graphite-solid grease.

The price of wago terminal blocks, after the fall of the ruble, became generally biting, but what can you do, after all, the thing was made for people.

As a field electrician, I had the opportunity to see how in all sorts of small families, dorms and other residential premises they use twisting of all types of wires and everything. Which of course often leads to overheating and all kinds of burnt contacts, people then sit without light and call ME!

Those same twisted wires that hold all the electrics together.

In general, you should not mix different metals in electrical connections - the risk of fire is very high!

And first of all: There is no need to get involved in electricity at all if you are an amateur. It's dangerous for health.

Personal experience using the Wago terminal block

I did an experiment at home. In a junction box , which is all on an aluminum wire from the developer. Poe bit off the aluminum and assembled everything on Wago terminals.

The input wires that powered the wiring from the shield were placed on separate “vags” and lined with copper. And this is what happened:

Aluminum wire with a cross-section of 1.5 square millimeters and copper 2.5 square, through the wago terminal block. Black with a graphite-solidol thing inside. It seems like the reliability is almost durable, however.

All this is a violation of “PEU”. It worked for 3-4 years and soldering stations, vacuum cleaners, and soldering hair dryers were used with a bang, no complaints. But when I started running a washing machine from the same line, miracles began to happen. Literally, in a month, after 6-8 washes as usual. The junction box: began to sing, groan, characteristically spark and show signs of instability. Several times even the surge protector went into protection (I have it with surge protection).

The alarm for burning and sparking of the wiring on the Wago terminal blocks rang, I climbed inside and what did I see?

The darkness and trash of this junction box reflects the general standard of living) The same wago terminal block that leaked - but continued to work. Connection of copper to aluminum Wago terminal block

BINGO! Everything melted to hell! The whole point is that the connection: copper with aluminum - does not heat up so much under the load of current passing through this connection. As a result, it is clear that the wago terminal blocks have been smashed into mush. Moreover, the copper wire is stuck, and the aluminum dangles like a hair. Of course, the “zero” burned out, but the phase contact also melted.

Types of WAGO terminal blocks

In general, there are a huge variety of terminal blocks and they are produced not only by the WAGO brand, terminal blocks are also made by Legrand and a bunch of other third-party manufacturers, which for some reason have not taken root in Russia. China, of course, does not lag behind and fakes everything with a bang.

The main types of wago terminal blocks are 3 types:

• Reusable terminal blocks - for soft wire;
• “Disposable” with a special paste for mixing aluminum and copper (I call it solid oil-graphite);
• “Disposable” without special paste, the body of which is transparent.

On good terms, all these types are suitable for low-current, fast switching networks, powering: uninterruptible power supplies, power supplies, spotlights, assembling lighting wiring and something from the same low-power series. Well, not for power supply, input wires and power panels with sockets.

Reusable, disposable and wago terminal blocks with paste

How to use wago terminal blocks

There was also a case when I received a call from a production plant outside the city. A small workshop - a sawmill for 5 and a half Uzbeks. Their electricity was constantly cut off, although all loads did not exceed 5-6 kilowatts. And the supply wire had a reserve of 2-3 times. The power supply panel of this workshop had a 32-amp input circuit breaker (freshly installed), but it was also turned off every half hour or hour.

An external examination revealed nothing. And when I already went directly into the contacts, I went nuts. The input wire is aluminum 10 squares, there is also copper 10 squares and there is a copper 3-phase jumper and all this is in one contact of the circuit breaker, of course the plastic melted and caused oxidation to everything that was happening.

But look from the outside, everything is fine - a new machine, the wires are laid, no traces of burning.

This shield was defeated by a brass 3-phase closed busbar. Be that as it may, the connection with bolts, even coupled with aluminum and copper, gave a much better effect than wago terminal blocks. People are happy, the workshop is working non-stop, they called and thanked us, and asked us to rebuild another panel.

Insulated brass busbar for 3 phases for DIN rail

Conclusion on wago terminal blocks

Wago terminal blocks are a good thing, but they are contraindicated for use on power (socket) lines . Use for lighting and light loads please. Although the manufacturer stated: load retention through wago up to 4 kW.

From experience I can say that this connection from the same type of wire (copper to copper) will last for 3-5 years, then the contact will begin to age and deteriorate.

Therefore, emotional twists, sealed with solder without acids and aggressive fluxes, are our everything!

The contact area of ​​the wago terminal block is very loose in twisting. The wago terminal block is burnt and melted. Wago terminal block with grease for aluminum and copper. Melted Wago terminal connecting aluminum and copper.

Source: https://ko-lipe.ru/opyt-ispolzovaniya-klemmnika-wago/

Connecting wires using crimping sleeves

In practice, several methods are used to connect electrical wires. They can be twisted, soldered, connected using electric welding or a special block equipped with bolted fastenings. Each method has its own pros and cons, which manifest themselves during operation of the line in operating mode.

For medium and high currents, the optimal way is to connect the wires by crimping with sleeves . This method achieves two important goals - the connection has excellent electrical contact and high mechanical strength.

Technologically, the method is very simple: the stripped ends of the wires to be connected are inserted into a special metal sleeve, and the sleeve is crimped using special tools. To do this, you need manual or mechanical press pliers, which provide very tight crimping of the contacts along the entire length. Hand pliers are used for sleeves with a cross-section of up to 120 mm2. Connections larger than this size require the use of a hydraulically driven tool.

If it is necessary to crimp a large number of sleeves of different sizes, you should choose pliers with an adjustable punch or rotary dies designed for different sections. For crimping small-diameter sleeves, pliers with shaped jaws, without dies and punches, are used.

In terms of mechanical strength, connecting wires by crimping exceeds all other methods, but it turns out to be non-separable. To disconnect the crimped wires, the switching section must be cut off. Both copper and aluminum wires of any cross-section are suitable for connecting wires by crimping.

Today I want to talk about such an interesting area as crimping single-core wires with sleeves and, as an example, consider crimping VVGng-3x2.5 sq. mm copper wires.

We will consider the process of crimping with sleeves in more detail using this operation to connect a single-core wire VVGng-3x2.5 mm2 with a copper core. Since the wires are copper sleeves, copper sleeves are also used for crimping wires.

In general, to connect the wire, it is necessary to select a sleeve that matches the material in order to maintain electrochemical compliance. Its diameter should be slightly larger than the thickness of the cable core. This is one of the options for connecting wires using crimping sleeves.

Sometimes situations arise when the wires need to be lengthened a little, for example, when it is necessary to replace a faulty socket or switch mounted in a wall lined with tiles or tiles.

The contacts, naturally, have long since rusted, and it is impossible to remove the old device by unscrewing the bolts. There is only one way out - cut it off. But in this case, you will have at your disposal scraps of wire that are not suitable for installation using conventional methods. You can't insert a screw block there, nor can you insert a WAGO terminal block.

There is only one way left - sleeving, i.e. connection of wires by crimping with sleeves. Sleeves for crimping are made of copper, aluminum or a combined composition, some of the modifications are tinned. The sleeves are produced in a full range and correspond to standard wire diameters.

What sleeves should I use for crimping wires? When using them, it is necessary to adhere to the principle of matching materials: copper wires are connected with copper sleeves, aluminum - with aluminum, copper with aluminum - combined.

I will not dwell in detail on what type and cross-section to choose a sleeve, I wrote about this in the article sleeves for crimping wires, please come in, read, ask questions. In this article I use GML brand sleeves - Copper Tinned Sleeve.

To connect stranded wires, such crimping sleeves are not used; in this case, it is necessary to use special insulated lugs.

How to connect wires by crimping in a junction box

In distribution boxes, the most common task is to route a 2.5 mm2 line into several directions. If copper wires are used, then the connection requires sleeves for crimping copper wires and special press pliers.

Let's look at how to crimp wires with sleeves in a distribution box; for example, let's branch the cable in the distribution box in three directions.

First, the insulation from the wires is cleared to a length corresponding to the length of the sleeve. The stripped ends of the wire are inserted into the sleeve very tightly so that there are no voids.

If they nevertheless form, which is often the case when three or more wires are connected, then it is necessary to “clog” them with sections of cores of the same wire, the length corresponding to the length of the sleeve.

I would like to draw your attention to one very important point. If you crimp several conductors into one sleeve, with a standard cross-section of wires and sleeves it will not be possible to pack the sleeve tightly; there are always voids left in it and these voids must be filled. To do this, you need to “finish off” the sleeve with several more pieces of the same wire. This will allow you to create high-quality and reliable contact at the crimping site.

Crimping of the wires is done with two or three presses in different directions (to do this, the press pliers just need to be turned 180 degrees). It is especially important to remember that the wires must not be twisted before connecting with a sleeve. For the specified brand of wire, when connecting four branches, another sealing piece of wire and a sleeve with a cross-section of 2.5 mm2 are required.

When the sleeves are put on and tightly finished off with pieces of wire, you can begin crimping. For this I use hand press pliers PK-16.

In order for the sleeve to be securely pressed, we do two presses along the edges of the sleeve (at the beginning and at the base). We do presses in opposite directions.

Crimping of wires is performed using GLM-10 sleeves. During operation, the working area of ​​the pliers must correspond to the size of the sleeve.

The photo clearly shows that the sleeve is compressed with two opposite presses. This allows you to improve the quality of contact at the junction.

The ends of the wires extending outward are cut with pliers to fit the edge of the sleeve.

The entire connection is insulated with a heat-shrinkable tube, the length of which is selected so that it extends 1 cm beyond the outer cut of the sleeve and extends onto the insulation by 1.5 cm. If you don't have heat shrink tubing, you can use electrical tape.

We heat the heat-shrinkable tube placed on the sleeves using a hairdryer. After compressing the tube, the connection points are reliably insulated.

After insulation, carefully lay the wires in the junction box and close the lid. All our wiring connections are done.  

Typical mistakes when connecting wires by crimping

Some important tips for novice electricians, or people who independently use such a connection method as crimping wires with sleeves .

1. Use of sleeves with a cross-section smaller than the wire

Never use sleeves smaller than the required diameter. To insert wires into them, it is necessary to reduce the diameter of the core, which is done by cutting off part of the conductor and reducing the cross-section of the wire.

Those. if you want to extend a wire with a cross-section of 2.5 mm2, and your sleeve is 1.5 mm2, you do not need to take a file and trim the wires so that they fit into the sleeve.

Thinning the wire leads to an increase in the resistance of the contact area and also reduces its throughput. Therefore, the purpose of maintaining the same conductivity along the entire length of the line is lost. At the junction, the wire begins to heat up and quickly collapses, it’s good if there is no smoke or flame.

Reducing the cross-section of the wire also leads to a decrease in the mechanical strength of the connection. With any external influence it can simply break. Finding a break in an extensive network is not an easy task even for a professional electrician, unless, of course, there are special instruments. But they are not in every home.

2. Use of large diameter sleeves

Increasing the diameter of the sleeve also does not bring any benefit. It is not always possible to achieve a reliable and strong connection. The use of the “folk” method of bending the ends of the wire in half can be considered only a partial solution. Practice shows that the mechanical strength of the pressed joint in this case is also reduced by almost half.

3. Cutting the cartridges into several pieces

Many beginners use this method to save on cartridges. Do not shorten the factory sleeve. This leads not only to the inconvenience of working with pliers, but also to an increase in resistance. The consequences are described in the first tip. Mechanical strength also decreases due to a decrease in the length of the contact section.

4. Crimping of wires with sleeves should be performed only with a special tool - press pliers

Engineering thought for performing such an operation as connecting wires by crimping with sleeves came up with a special tool - press pliers.

Therefore, you should not use pliers for these purposes, and especially not a hammer. You can flatten the wires, changing their geometry, and thereby the resistance of the section, damage the sleeve itself, and break the wire.

Connecting wires by crimping sleeves is not a complicated operation, but it requires careful execution and compliance with safety precautions, like all work with electrical wiring. The crimp density and reliable insulation of the connection area are especially important. It is not recommended to use homemade sleeves. It will not be possible to save much on them, and the reliability of the connection will be much lower than when using factory sleeves.

Source: https://electricvdome.ru/instrument-electrica/opressovka-provodov.html

Why use a junction box

Wiring connection in the junction box

There are cases when, when installing electrical wiring, they neglect the installation of such distributors, considering that this is just a waste of time, since the box must first be installed, then the connections to it must be made, which will lead to additional difficulties. It’s easier to simply twist, insulate and simply plaster the wall. But here you need to think a little ahead, since in this case important points are missed:

• No free access to wires. For example, if the socket in your room does not work or the light has gone out, and after checking it turns out that the problem is a lack of voltage. How to check? Completely remove the trim? Tearing off wallpaper and plaster to get to the twist? This will ruin your renovation.
• If you want to install an additional outlet. It is not always convenient to connect it by laying wires from a previously installed outlet. Thanks to the distribution box, you can easily make new connections.
• The regulatory document PUE states that “places of connections and branches must be accessible for inspection and repair,” therefore the installation of such a distributor cannot be neglected.
• The absence of such distributors is contrary to fire safety standards.

As you can see, the distribution box plays an important role. But installing it is just the beginning. All that remains is to connect all the wires in it. What's the best way to do this? Let's look at some ways.

Types of connections

Types of wire connections

What is the task when connecting wires? Ensure good contact between the cores so that the chain does not break and there is no risk of a short circuit. In order to ensure this, you can act in several ways:

1. Twisting.
2. Crimping.
3. Welding.
4. Soldering with a soldering iron.
5. Use of screw terminals.
6. Bolted connections.
7. Self-clamping terminals.

These are time-tested methods that you can use to ensure reliable contact. Let's take a closer look at each of them. You will learn how to properly connect wires using any of these options.

Twist

Twisting wires

Such twists in the distribution box are officially prohibited. The seventh edition of the regulatory document PUE, chapter 2, paragraph 2.1/21 lists all types of permissible connections, but there is no twisting in them.

And this is not surprising, since such a contact is sensitive to pulse current and has a high transition resistance. Over time, the contact will deteriorate and simply burn out.

Due to the fact that the contact area is small, heating occurs under heavy loads and the contact is weakened even more.

It is not recommended to use this type of connection, although some craftsmen still use it. If you choose twisting, all responsibility falls on you.

This option is chosen because of its simplicity. It is enough just to strip 10–20 mm of insulation and twist the wires together using pliers. This is what our fathers and great-grandfathers did. But such a connection is often unreliable, especially if an aluminum core is used.

Crimping with a connecting sleeve

Cross-sectional crimping of copper wires

A fairly reliable method that will require the purchase of a connecting sleeve. You need to select it based on the diameter of the bundle being connected. Depending on the wires you connect, the material of the sleeve itself is selected.

For copper wires the sleeve must be copper, for aluminum wires - aluminum. To ensure a reliable connection, the sleeve is crimped with a special tool called press pliers.

This technology is quite effective and is included, along with other methods, in regulatory documents.

Crimping connection of aluminum wires

To connect this way you need:

1. Remove the insulation, taking into account the length of your sleeve.
2. Twist the wires into a bundle and insert them into the sleeve.
3. Compress the sleeve using press pliers.
4. Insulate the twisting area with heat shrink or insulating tape.

It is not recommended to use pliers in such work, since the connection will not be reliable enough. It is much better to buy press pliers or borrow them from good neighbors.

Welding

Welding wires

This method can be called the most reliable and safe, because the wires are connected using fusion and become one. Due to the fact that the welding will not oxidize, such contact will not weaken over time. But to carry out such work you will need skills in working with welding equipment.

In addition to skills, you must prepare:

• 24 volt welding machine with a power of more than 1 kW;
• welding gloves for skin protection;
• welding glasses or mask;
• sandpaper for stripping wires;
• stationery knife for removing insulation;
• carbon electrode;
• flux, thanks to which the melt will be protected from exposure to air.

Welding copper to aluminum

After all the tools and materials are ready, all that remains is to do the welding, which will not be difficult. The work can be divided into several steps:

1. Remove 60–80 mm of insulation and clean them using sandpaper. The veins should shine.
2. Connect the wires using the twisting method, twisting one onto the other so that the ends are level with each other. It is recommended to make the length at least 50 mm.
3. Pour flux into the recess of your electrode.
4. Place the ground of the device on the bare wire, turn on the welding machine and press the electrode to the top of the twist.
5. Hold the electrode until a ball called a contact point forms. This usually takes 1–3 seconds.
6. All that remains is to clear the point of flux and insulate the welding site with heat-shrinkable tubing or electrical tape.

This type of connection will last a long time. In some old Khrushchev buildings, such welding lasted 50 years and consistently performed its function.

Soldering with a soldering iron

Soldering twists with a soldering iron

The method is very similar to welding, only in this case the wires are connected using solder. For these works you will need a soldering iron. To work you will need:

• soldering iron;
• fine sandpaper;
• rosin (flux);
• brush for applying rosin;
• tin-lead solder.

The operating procedure is the same as for welding:

1. Removing insulation and cleaning with sandpaper.
2. Twisting.
3. Application of flux.
4. Direct soldering. The soldering iron melts the solder, which should flow into the twist itself, reliably connecting the wires to each other.

Soldered wiring in the junction box with a soldering iron

Often copper wires are soldered using this method, but if you purchase special solder for soldering aluminum, you can also solder copper from aluminum.

Soldering is quite reliable, but is not recommended in areas where there may be strong heat. Moreover, under mechanical stress, the connection may weaken.

Using screw terminals

Connection of copper and aluminum wires

This method is fast, simple and effective. And most importantly, such clamps can combine dissimilar metals. For example, if you need to connect aluminum and copper conductors, which in itself, as you know, is contraindicated. These clamps are very simple and compact, and their cost may pleasantly surprise you.

Terminal blocks

To connect wires with clamps you only need to complete 2 steps:

1. Remove 5 mm of insulation.
2. Insert into the clamps and tighten the screw.

Melted terminal block contacts

That's all, as you can see, everything is very simple and fast. It is only important to control the force with which you clamp. If you tighten the screw too tightly, you may damage the wires. You need to be especially careful when working with aluminum wires.

Crimp lugs

The only disadvantage of a screw connection is that when working with a multi-core cable, it must be crimped with a special nozzle to ensure normal contact and integrity of the wire.

Bolted connections

Bolted connection

This connection is quite reliable, but cumbersome. It is not suitable for modern distribution boxes due to its dimensions, but for large old-style boxes it is just right. This method can be used to connect both homogeneous and dissimilar metals. The work is carried out as follows:

1. A steel washer is placed on the bolt.
2. The insulation is removed from the conductors and they are formed into a ring.
3. The first ring is put on the bolt.
4. Then comes another steel washer, which is placed on the bolt after the first.
5. The second connecting wire is put on top.
6. This entire “sandwich” is clamped with a nut.
7. In the end, everything needs to be insulated.

It is this design that makes the contact bulky. If you need to connect several pairs of wires, then this option will not be the best.

Self-clamping terminals

This method can be called the most modern, popular and easy to use. All you need is to buy special terminals at the store. Inside these terminals there is a special paste that prevents metals from oxidizing. Thanks to this, various metals can be inserted into such joints.

https://www.youtube.com/watch?v=ZH1ZLOYL_xo

The work is as follows:

1. 10 mm of insulation is removed from each wire.
2. The lever, which is located on the clip, rises up.
3. The conductors are inserted into the connector.
4. The lever lowers to its original position.

If your clamps do not have levers, they must be inserted until the terminal snaps into place.

Connecting wires with a terminal block without levers

We have looked at the most reliable methods by which you can combine wires in a junction box. This is a very important stage of electrical installation work, since 70% of errors during the work consist precisely in incorrect connection of conductors.

But if you, even without experience in such work, use the methods given in this article, you can easily do everything in accordance with the requirements of the regulations. But which of these methods to choose depends on your capabilities and desires.

This video shows how to connect wires in a junction box:

You will learn everything about sleeving wires or crimping lugs from the material provided in this video:

Scheme

Box diagram

Switch and socket block diagram

Connection

Junction box connection diagram

Connecting sockets

Switch connection diagram

Junction box

Connecting wires

Wire connection diagram in the box

Source: https://kakpravilnosdelat.ru/kak-soedinit-provoda-v-raspredelitelnoy-korobke/

How can you connect the wires in a junction box?

The connection of wires affects the safety and reliability of electrical wiring. It is performed in different ways, using connecting devices and devices, depending on the characteristics of the wires.

Why use a junction box?

A distribution (otherwise a junction box, a branching box) is a type of installation box in which wire switching and electrical connections are made. It can be round, rectangular, square in shape, plastic, steel, fiberglass, aluminum in material.

The device is a container, the purpose of which, in any method of connecting wires in a distribution box, is to hide the branch of the electrical network. In addition, it allows you to effectively redistribute the load on networks and prevent short circuits in them.

There are many ways to connect wires in a junction box. The simplest one - twisting - was previously a priority. Today it is considered dangerous and unreliable. It was replaced by special connecting devices, devices designed for the various characteristics of the cables being connected.

Methods for connecting conductors

Correctly connecting the wires to each other means ensuring the reliability and safety of the electrical network. There are numerous types of wire connections. You can use long-used ones - twisting, soldering, bolting. It’s easier and faster to get the job done by using a cable connector - a special device that allows you to reliably connect cables of different diameters, single- and multi-core, from various materials,

Using Terminal Blocks

Blocks for connecting wires are a type of electrical installation products. They are called terminal blocks, terminals, terminal blocks, terminal blocks, KB, terminal clamps, terminal connectors. Contains 2 metal contacts or more. The latter have nodes in which cables are secured and are placed inside a dielectric housing, often sealed (filled with gel).

There are many types of terminal connectors. They are distinguished:

• by installation method: screw, detachable, push, barrier, pass-through;
• single-, double- and multi-row;
• for one-, two-, three-row and multi-tier cables;
• angular and straight;
• for single- and multi-core, flexible conductors;
• according to the method of wire clamping: screw, spring, knife, end.

Source: https://odinelectric.ru/wiring/wires/kak-soedinit-provoda-v-raspredelitelnoj-korobke

How to properly twist wires

The electrical network got its name for a reason. It covers all rooms like a web, ensuring the operation of the equipment. To distribute energy between individual connection points (sockets, switches), junction boxes are used. One cable goes into them, but several come out. A prerequisite for safe operation of the electrical network is to twist the wires correctly and accurately. To do this, you can use different methods.

To better understand how to do twisting correctly, let’s figure out what options exist, the order, and the features of their implementation. Electricity is considered one of the communications that “do not forgive” mistakes.

The result of illiterate actions is damage to the device, short circuit, or fire.

Beginning craftsmen often ask: is it possible to connect the wires in the junction box yourself? Of course, but before that you should take the time to study the rules and features of electrical work.

Wire connection methods

There are different ways of tightening wires in a junction box: crimping, welding, soldering, various clamps. Some require more time, special materials, and equipment. Others are easier to implement, but poor execution significantly reduces their reliability.

Twisting is popular among folk craftsmen. The PUE classifies it as an unreliable method that does not guarantee reliable contact. It is usually used as a temporary option, for example, when checking the functionality of a circuit. In addition, it is considered preferable for sagging, loose networks. Advantages:

• ease of execution;
• minimum tools;
• Easy to disconnect if necessary.

One of the disadvantages is the difficulty of working with wires of different sections: the difference in resistance leads to heating of the insulation, its gradual melting. They try not to use this method for multi-core cables, since the probability of a circuit break is high.

Do not twist copper and aluminum wires: the result will be unreliable, the point of contact will become a source of increased resistance.

The easiest way to twist wires is by twisting the previously stripped ends together. The tools you will need are a knife and pliers. First, a section of the core 5 cm long is cleared of insulation. The bare ends are crossed, bringing the individual parts as close as possible. Then use pliers to rotate the crosshair, bend it in any direction parallel to the main line, and isolate it.

Types of wire connections

You can use another option, when the stripped ends are folded in the middle and interlocked. Then the wires are wrapped together. For reliability, they are crimped with pliers and insulated. Electricians know many methods of twisting: parallel or serial bandage, groove. Correct twisting should ensure the most complete fit of the cores.

Electrical tape is usually used for insulation. It is necessary that it extends at least 2-3 cm onto the insulation. You can use a thermotube. It is first put on the cable, then moved, covering the contact point. The tube should tightly grip the wiring, so it is heated a little.

For crimping, you will need a special sleeve, selected for the size of the bundle and the cable material. The stripped ends of the core are inserted into the sleeve, crimped with press pliers, and insulated.

In terms of reliability and quality, welding gives the best results. In fact, they get a one-piece structure that is protected from oxidation and rupture. To perform this you will need a welding machine, carbon electrode, and flux. Step-by-step implementation instructions:

• strip the ends of the cable from insulation, bring them to a shine with sandpaper;
• twist the wiring;
• fill the recess of the electrode with flux;
• weld the contact point.

Clean the resulting “ball” from flux and coat it with varnish. Similar actions are performed when soldering. Here the contact is provided by solder melted using a soldering iron.

Twists of copper and aluminum wires

A lot has been written about why copper and aluminum should not be combined with each other. The consequence of such contact is its heating, subsequent combustion. There are several reasons for this behavior of metals:

• Difference in thermal expansion coefficients. Metals expand differently when heated and contract when cooled. Therefore, their connection gradually deteriorates.
• Formation of an oxide film on aluminum. The film prevents the passage of current, the conductor heats up, and the connection is gradually destroyed.
• Violation of the aluminum structure during electrolysis. Copper and aluminum form a galvanic couple. Under the influence of moisture, dissociation of ions begins, which leads to the destruction of the metal. The resulting shells and voids conduct current poorly and cause heating.

The presence of aluminum wiring in houses leads to the need to combine it with new copper conductors. Using simple rules, you can avoid heating the contact and ensure its reliability. When performing twisting, it is important to wrap the conductors around each other. The number of turns is more than 3 for a thick wire, at least 5 for a thin wire (less than 1 mm). The finished connection is sealed with a protective varnish that is resistant to water.

Maximum reliability is ensured by a method in which the copper is pre-coated with solder. This creates reliable contact between single and multi-core conductors. To do this, the multi-core wire must first be tinned with solder, it will become single-core.

To make the contact detachable, use a bolt, nuts, and spring washers. All elements are placed on the rod one by one, avoiding the combination of copper wires and aluminum. For example: a conductor with a diameter of less than 2 mm will fit perfectly on an M4 bolt.

The development of electrical engineering has brought new comfortable ways of working with different materials. An example is a terminal block. Its advantages:

• comfortable;
• reliable;
• eliminates contact between bare areas.

The end of the core is stripped of insulation (approximately 5-10 mm), inserted into the hole, and clamped with a screw. The terminal box is indispensable when restoring a broken circuit or connecting a chandelier. It can only be placed in the wall in a junction box.

The Wago terminal block is deservedly popular. It can be disposable or reusable (with a lever). The terminal block works simply: insert the cable with force, it is fixed. Disadvantage: more expensive than other traditional means.

The danger of twisting copper and aluminum wires

Twisting wires of different sections

Often the master is faced with the task of connecting wires of different diameters in a junction box. This can be done in several ways: twisting followed by soldering (welding), screw terminals, self-clamping terminals, bolts, nut-type couplers, tinned copper lugs.

The easiest way is to twist wires in a box that are similar in thickness (for example, 4 and 2.5). With a large difference, it is difficult to ensure high-quality contact. The wires must wrap tightly around each other, then they are welded or sealed. A strong connection will last for many years without complaints.

A reliable contract between conductors of adjacent cross-sections is created by the ZVI screw clamp. The cables are inserted from different sides, each clamped with a separate screw. The choice of clamp is made taking into account the characteristics of the conductors and the permissible current. Execution principle:

• strip the ends by 2-3 cm;
• insert them into the box;
• tighten the screws.

If the wires have a large cross-section, you can twist them using a Wago self-clamping terminal. Its peculiarity is the presence of special sockets for each core. Marking the terminal body will help you figure out how many wires you can twist and what cross-section.

Long-lasting contact of the wires in the junction box is guaranteed by a bolted connection. It allows you to fasten two, three or more wires using nuts, washers, bolts. Step-by-step mounting instructions:

• strip the core by 3 cm (you should get a full turn);
• prepare a ring from the core according to the diameter;
• put a washer on the bolt, a ring of one conductor, another washer, a ring of the second conductor;
• Place the next washer and tighten with the nut.

This way you can connect several wires together. Their number is limited only by the length of the rod.

The question often arises: how to twist the wires together to branch from the main line in the distribution panel? The solution most often is a branch compression, in common parlance - a “nut”. It allows you to branch a line from it without cutting the main line.

To do this, the desired place in the main part is cleared of insulation, a clamp is attached, and an additional “branch” is inserted. It can also be used to connect two separate cables. When choosing a “nut”, you need to know the cross-section of the main cable and branches.

Using compression, you can connect a copper wire to an aluminum one.

The body of the “nut” is not sealed. To protect it from moisture, dust, and debris, it should be insulated.

The compression connection procedure is simple:

• disassemble the housing by removing the retaining rings with a screwdriver;
• strip the insulation (the length corresponds to the dimensions of the die);
• loosen the fastening;
• insert the cores into special grooves on the dies;
• carefully (without overtightening) tighten the bolts;
• place the die in the body;
• close the housing, install retaining rings.

To work with a thick cable, you will need copper-tind lugs and crimping pliers. The connection turns out to be bulky, so you will need to provide enough space in the box for it. A ferrule is put on each core, crimped, secured with a bolt and nut, washer, and insulated (with electrical tape, heat pipe)

Reliable wire connection

Errors when twisting wires

A common mistake when twisting is to wrap one wire around another. This option does not provide the required mechanical strength. The conductors should wrap around each other evenly. It is unacceptable to screw a thin conductor onto a thick one; a tight fit will not be achieved.

The length of the twist depends on the cross-section of the wires. It should be at least 3-5 cm. Options for clutching in a ring, loose fit, or not twisted are unacceptable.

Direct connection of copper with aluminum leads to rapid destruction of the contact. Craftsmen often forget to install an intermediate plate, which will prevent direct contact of metals.

Source: https://uzotoka.ru/montazh-elektroprovodki/pravilnaj-skrutka-provodov.html

How to connect wires in a junction box?

Electrical wiring is an integral part of the installation of any electrical network. The electrical network ensures the distribution of electricity. Sections of wires may be under a layer of plaster. But they can be laid in one way or another on the surface of walls and ceilings. In any case, they must be securely connected to each other. For this purpose, distribution boxes are installed in certain places.

Following their installation, the installation of wires is done. First, before connecting consumers, a wire connection diagram is prepared. If you hear such a name as a wiring diagram, it means that we are talking about supplying power to several consumers. Unplugging the junction box does just that. The wiring diagram in the junction box always contains the main power wire.

Distribution boxes are where the wires of sockets, switches and other loads are connected. This is the node where the electrical wiring branches. Electricians coined the word "disconnection" to apply to such branching. It is purely colloquial and is not used in technical literature.

The connection of wires in a round shaped junction box is usually used for hidden electrical wiring. In this case, it is easier to prepare the installation site using an electric drill with a special drilling device.  

The first stage of creating a junction box The second stage Installation of a round junction box

The shape of the box in relation to the manufacturability of its installation for external wiring is not so important. However, a rectangular box provides more space and may be preferable for this reason. Next, we will tell readers how to connect the wires in the junction box.

Connection methods

Connecting the wires in the box is done in two main ways:

• twisting the connected wires (twisting);
• using special accessories. These wire connectors in the junction box are called terminal blocks and blocks. All connecting devices make electrical contacts using a screw or elastic clamp.

It is not difficult to twist even several strands of wires inserted into a junction box. Twisting is the simplest fixed contact. But the ease of obtaining results has a bad effect on the quality of this contact. The main disadvantages of simple twisting are the following:

• relatively small contact area (especially for large cross-section conductors);
• lack of compensation for oxidation and weakening of compression of the contacting conductors.

Wire twisting Regular twisting

Therefore, conventional twisting should be used only for minor electrical loads in the range of 100–300 W. Before connecting the wires in the junction box, it is necessary to correctly determine the length of the contact of the wires. If it is impossible to accurately predict the current strength that will pass through the twisting, its quality must be improved in one of the following ways:

• cover with solder (solder);

Soldered twist Improving the quality of twist by welding

In addition to welding and soldering, special accessories are often used that fix the contact of the cores. Of these you can

• use a crimping cap screwed onto the twisted wires.

View of the junction box after connection Fixing the twisted conductors with a cap

The cap is also called a connecting insulating clip - PPE

If it is necessary to install a powerful consumer of electricity, the use of caps and long twists formed with their help is allowed. How this is done is shown in the images below.

Screwing on the cap The wires are inserted into the cap The wires are fixed with electrical tape The final view of the insulated wires Correct twisting of the wires

• Use a sleeve that crimps either twisted or straight wires;

Another option for connecting wires Wires laid in a box This is how everything should look Using sleeves

• use tips;

Using the tip

• connect the wires with a terminal block;

Terminal blocks in distribution boxes

• Use terminal blocks of a suitable design.

Connection of terminals Various types of terminals Terminal blocks in the distribution box

Comparison of methods

The images provided above clearly demonstrate that the connection of the cores can be done in several ways. Therefore, we will next consider their disadvantages and advantages.

Quality and safety

Once the junction box has been connected, it is usually forgotten about for at least several years.

But how to correctly determine the wires of sockets, switches and other elements after a few years during repairs or for another reason? To easily solve this problem, at the installation stage a diagram of the distribution box is drawn.

It must be placed inside before closing the box. Now, even after opening it several years later, after familiarizing yourself with the diagram, it will be clear where which wire is in the box.

Crimping pliers with calibrated jaws

The correct connection of wires will mainly determine the reliability of the electrical network. The methods of connecting wires in the junction box must be linked to the current load.

When installing the socket, you need to draw a wire from the distribution box of such a length that you get a long enough twist for the cap (as shown in the images above).

But connecting by soldering or welding the cores will be the best solution, especially if you connect several sockets in a circuit. An example of the consequences of an incorrect choice and poor-quality installation is shown below in the image.

Terminal block is on Result of incorrect connection

The result may be a fire and the loss of a significant part of the property. To prevent this from happening, you need to choose the right method and accessories for connecting the wires. And then install everything correctly. If you read the article carefully, it will not be difficult for you to do this without errors.

Source: https://domelectrik.ru/provodka/kabel/soedinenie-v-raspredelitelnoy-korobke