How to properly connect electrical wires

Connecting wires

To ensure full electrical conductivity, the integrity of the wiring is an important point. Damage or poor-quality adhesion is unacceptable.

It is important to ensure tight contact contacts and reliable connections in the “electrical node” areas. There are certain methods for eliminating cable breaks.

Among them, welding should be noted. It applies to copper and aluminum wires. This ensures a particularly reliable grip.

Connections can be divided into types:

• twist;
• welding;
• soldering;
• pressure testing;
• terminal blocks;
• self-clamping terminal blocks (WAGO terminals);
• PPE caps;
• bolt clamp.

The most complete connection for wires made of copper is soldering. It can be easily accomplished using flux (rosin, borax) and tin solder. Terminal blocks are also used - a special device that is made using screw terminals. They are selected separately in accordance with the cross-section of the cores.

Self-clamping terminal blocks are often used to save time on electrical installation work. In order to isolate a twisted or soldered electrical connection, PPE insulating caps are used. Today in the energy sector, WAGO terminals are widely used, which are produced for wires and cables of various diameters. In addition, WAGO terminals allow you to connect conductors made of different materials (copper and aluminum).

The choice of which connection to use depends on various factors:

• material (steel, copper, aluminum);
• number of twisted elements;
• section;
• place of work (house, street, in the ground, etc.).

Is it possible to twist wires of different sections? — Metals, equipment, instructions

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

Here are the factors that determine the choice of connector:

1. Core material (copper, steel, aluminum).
2. Working conditions (outdoors, in an apartment, in water, in the ground, in the floor, normal conditions).
3. Number of conductors (two, three, four, etc.).
4. Core cross-section (same, different).

Based on these factors, the most suitable and correct method is selected. First, let's look at the materials that can be used to connect electrical wires in a junction box.

Existing methods

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

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

Let's consider the essence, advantages and disadvantages of each method!

Using Terminal Blocks

Terminal blocks are plastic products containing a brass bushing with screws on both sides.

In order to connect two wires to each other using a terminal block, you need to insert one end of the product on each side and tighten them thoroughly with screws (with force). This connection method is most often used in junction boxes, as well as when installing chandeliers, switches and sockets.

Please note that terminal blocks come with different inlet holes, suitable for a specific cross-section of the wire.

Advantages:

• low price of terminal blocks;
• fast and convenient installation of products;
• good quality of fastening;
• You can combine aluminum with copper.

Flaws:

• Very often the terminal blocks are of poor quality, which can lead to breakage of the connector during installation.
• Possibility of combining only two conductors with each other.
• It is not recommended to tighten aluminum and stranded products with terminal blocks. This is due to the high fragility of aluminum and the thinness of the stranded wire: when tightening the screws, the contacts may be damaged.
• When using soldering, reliability will be significantly higher.

Spring terminals

Wago spring terminals appeared on the market relatively recently and have undoubtedly become the most effective and safe connectors.

The difference between Vago terminal blocks and conventional terminal blocks is that a special mechanism is used to connect electrical wires, rather than a screw. This lever-type mechanism allows you to carefully fix the product without damaging it. In order to carry out the vagami fastening yourself, you need to strip the insulation and insert the cores into the hole.

Please note that there are disposable and reusable Vago terminal blocks. The first option involves a one-time connection, and it will no longer be possible to restore it when repairing the electrical wiring: it will be necessary to cut off the cable, repair the problem and install a new terminal block. Wago reusable terminals are more expensive, but with their help you can easily disconnect the contact if necessary.

Wago advantage:

• possibility of combining aluminum and copper conductors;
• the ability to connect several cores at the same time (more than two);
• wago clamps allow you to fix a thin stranded wire without damage;
• terminal blocks are very compact;
• the work does not take much time;
• good quality of fastening;
• The Vago terminal block has a special hole that allows you to control the operation of the electrical network using an indicator screwdriver.

The only drawback is the higher cost of the terminals.

Installation of PPE caps

PPE stands for connecting insulating clips. The products are ordinary plastic caps that have a special spring inside that holds the wires.

How to connect electrical wires with lugs

Another way is to use tips. The tip looks like a piece of tube, cut and turned flat on one side. A hole for a bolt is drilled in the flat part. The lugs allow you to connect cables of any diameter in any combination. If it is necessary to connect a copper cable to an aluminum cable, special lugs are used, in which one part is copper and the other is aluminum. It is also possible to place a washer, brass or tinned copper, between the tips.

The ferrule is pressed onto the cable using a crimper, similar to how wires are connected using crimping.

Insulation methods

Cable connections without insulation are unsuitable for operation. To complete the twisting, it must be protected from the external environment. To do this, you need to select one of the insulating materials:

• rag or PVC electrical tape;
• heat-shrinkable tubes;
• connecting insulating clamp (PPE).

Insulation using PPE caps
Insulating tape is the oldest and most familiar option to every installer. Heat shrink tubing is convenient. Their main advantage is compactness. PPE is the fastest method of isolation. They are made in the form of caps placed on the bare ends of the wires.

Note! There are 2 types of electrical tape: PVC-based and rag. What to choose should be determined based on the situation. PVC tape is more airtight and easier to work with. But it does not stick well in the cold and is capable of unwinding itself from the twist. Cloth tape performs better in the cold. But it is easily soiled and can become saturated with water.

The PUE does not consider twisting as a permitted method of connecting wires. However, such a connection is extremely common in low-current circuits. Without knowing how to twist correctly, you will not be able to connect the cable securely.

Insulating twists with electrical tape

A good twist has minimal contact resistance. The contact should be as strong and tight as possible. If you twist the wires in compliance with these rules and no large current flows through the contact, then it will last for decades.

Options for twisting stranded wires

In practice, 3 methods of twisting flexible stranded wires are used. The choice of method is made according to the situation and based on the preferences of the master. The methods are:

• serial connection;
• parallel connection;
• thin wire bandage;

Serial twisting

The stripped wires are applied to each other so that they form a crosshair. Then the conductors are twisted together. The connection made is symmetrical relative to the crosshairs. The ends of the wires stick out in opposite directions. After twisting, it is advisable to slightly tighten it so that it tightens.

The method is good due to the compactness of the resulting connection. Its thickness does not exceed 3 diameters of the insulated wire. Care must be taken. If the twist is protected from moisture by a heat-shrinkable tube, then the insulation is put on the core before making the connection.

Parallel

The insulation is removed from the ends of the wires. The cores should be connected so that the stripped sections are parallel. The ends of the wires point in the same direction. The current conductors are then wound onto each other in a spiral shape

It is important to make the connection as tight as possible, but not to break the conductors with excessive force

This twist can be found in the junction box. To protect the contact, electrical tape or heat shrink is used. For temporary and non-essential connections, it is allowed to use a PVC pipe (cambric) for insulation.

Bandage twist

The banded connection of cores is suitable for connecting thick wires that are difficult to bend with your hands or pliers. Current-carrying conductors are laid next to each other. They must first be properly cleaned on all sides using a needle file or file. Then the bare wires are tightly wrapped in a circle with the maximum number of thinner wires. A similar connection is used on power transmission towers.

Important! Do not connect the cable cores in a knot. The contact will be maximally tensile strength, but extremely unreliable in terms of electrical conductivity

Types of twists

There are dozens of twist options. They differ in the structure of current-carrying conductors, material and complexity of manufacture. If we consider from the point of view of purpose, twists are divided into 2 categories:

1. Branch. The 1st wire remains intact. Only a piece of insulation is removed from it. Another wire is wound onto the bare current-carrying wire.
2. Extension. Used to connect the free ends of 2 wires of the same cross-section. Cables are lengthened in this way.

Stranded wire branch

Sleeves

The third simple way to connect conductors is crimping with sleeves.
GML sleeves are most often used for joining copper wires. Deciphered as:

Sleeve

Copper

Tinned

For connecting pure aluminum - GA (aluminum sleeve):

To switch from copper to aluminum, special adapters GAM:

What is the crimping method? Everything is quite simple. Take two conductors and strip them to the required distance.

After this, on each side of the sleeve, the conductors are inserted inside, and the whole thing is crimped with press pliers.

Despite its obvious simplicity, there are several rules and nuances in this procedure, if not followed, you can easily ruin a seemingly reliable contact. Read about these mistakes and rules on how to avoid them in the articles “5 Rules of Crimping” and “Crimping Insulated Tips, Sleeves and Terminals”.

To work with conductors of large sections 35mm2-240mm2, a hydraulic press is used.

Up to cross-sections of 35mm2, you can also use a mechanical one with a large span of handles.

The sleeve must be crimped two to four times, depending on the cross-section of the wire and the length of the tube.

The most important thing in this work is to choose the correct sleeve size. For example, when connecting a monocore, the sleeve is usually taken to a smaller cross-sectional size.

For example, when connecting a monocore, the sleeve is usually taken to a smaller cross-sectional size.

And in this way you can connect several conductors at one point at the same time. In this case, only one sleeve will be used.

The main thing is to completely fill its internal space. If you are crimping three conductors at the same time, and you still have voids inside, then you need to “fill” this free space with additional pieces of the same wire, or with conductors of a smaller cross-section.

Only after this can you press.

After crimping, such a connection must be insulated. The most convenient way to do this is with a heat-shrinkable tube HERE.

There are tubes with an adhesive base. When heated, this glue flows out and ensures the tightness of the connection.

Insulation using a thermal tube is also a fairly simple process. In the absence of a gas burner or hair dryer, even a lighter is sufficient for small sections.

Sleeve crimping is one of the most versatile and reliable connections, especially when it is necessary to extend the cable, including the input cable.

In this case, the insulation turns out to be almost equivalent to the main one, when also using the outer tube HERE as a casing.

Connection of copper and aluminum conductors

The rules prohibit twisting copper and aluminum wires. However, in reality it is not always possible to follow such norms. If you decide to twist copper with aluminum, then you need to consider the following:

1. The connecting twist must be easily accessible. Avoid touching the connection with flammable materials.
2. Humidity increases the risk of curling. Water will accelerate oxidation, overheating and poor contact.
3. The connection is not suitable for power circuits. You should not load it with more than 500 W.
4. The resulting contact requires tightness. Moisture in the air will damage the twist.
5. It is necessary to periodically monitor the connection status. It is better to replace the aluminum wire with a new one made of copper.

Bolted connection of copper and aluminum wires

How many wires should be in a twist?

Most often, it is recommended to collect no more than 6 cores with a cross section of 2.5 mm2. in one twist, or better, especially if you have little experience, no more than 4 times. Cables with this cross-section are used in apartments for socket groups.

You can take more conductors with a cross section of 1.5 mm2 used for lighting. And the cables going to the electric stove have a conductor cross-section of 6 mm sq. As you understand, even six pieces are very difficult to neatly twist together without experience.

In order not to memorize the maximum number of wires recommended for twisting:

There is a simple rule:

The total cross-section of all wires in a twist should not exceed 16 mm2, and the total number of wires is 6 pieces

Standard distribution boxes most often have up to 6 cable entry points, so twisting with a large number of conductors usually does not work.

Another simple explanation for the limitation of the maximum number of cores is the following: a larger number simply will not allow the tool to properly grasp them when working.

Therefore, I recommend not twisting more than 6 wires at the same time. But, with some skill and strong hands, or using various devices, in rare cases you can twist up to 8 pieces.

Below is a table that shows the recommended maximum number of wires in one twist for different cable sections:

When making electrical installations, try to avoid cases where it is necessary to twist more wires than are recommended here.

It is always better to make an additional junction box than to get a poor-quality connection, which will then cause you a lot of problems.

And once again I would like to remind you that officially, simple twisting in electrical applications is prohibited and is used only in combination with other connection methods - compression, welding, etc.

I am sure that there are a lot of people who will say that they can easily twist a larger number of wires with high quality, and the resulting connection is as reliable as possible. I won’t argue with this; moreover, in my practice I’ve had to do something like this (I always weld conductors after twisting).

A striking example of this could be an article about extending the input cable to an apartment, where 3 wires of 6 mm square were twisted. When using certain technologies, this is possible, but I do not recommend doing this all the time; use this opportunity only as an exception.

What do you think? Tell us about your experience in installing twists and the maximum number of wires that can be done efficiently. I am especially interested in the opinion of novice electricians who have decided to do wiring in an apartment or country house.

Errors when making twists

Most errors are related to the shape, size and tension of the twist. To properly connect two wires, they should be wound evenly around each other. Between the current conductors there should be a maximum contact patch area. It is considered incorrect to wind one core onto another if they have a different cross-section.

Another mistake is twisting it too short. The longer it is, the larger the contact area. This means lower resistance and possible heating. The length of a good twist is at least 5 cm.

When making a connection, it is necessary to select the correct tension. Too much force can break the twist, and too little will lead to poor electrical contact.

When installing wiring, electricians often use various tightening devices. They are a bit with a special attachment for wires, which is inserted into any drill. This device turns the power tool into a semi-automatic wiring installation machine. It is possible to do it yourself. But it’s much easier to buy ready-made ones. For example, the screwdriver attachment from Tundra, in addition to connecting wires, is capable of removing insulation.

Methods for connecting wires or cables to each other

The junction of two conductors must meet the following requirements:

• reliability;
• mechanical strength.

These conditions can also be met when connecting conductors without soldering.

Crimping

This method requires special equipment. Crimping of wires with sleeves is carried out for both copper and aluminum wires of different diameters. Depending on the cross-section and material, the sleeve is selected.

Crimping algorithm:

• stripping of insulation;
• stripping wires to bare metal;
• the wires need to be twisted and inserted into the sleeve;
• the conductors are crimped using special pliers.

Selection of a sleeve causes major difficulties. An incorrectly selected diameter will not ensure reliable contact.

Bolted connection

Bolts, nuts and several washers are used for contact. The connection point turns out to be reliable, but the structure itself takes up a lot of space and is inconvenient to install.

The connection order is as follows:

• stripping of insulation;
• the stripped part is laid in the form of a loop with a diameter equal to the cross-section of the bolt;
• a washer is put on the bolt, then one of the conductors, another washer, a second conductor and a third washer;
• the structure is tightened with a nut.

Using a bolt, you can connect several wires. The nut is tightened not only by hand, but also by a wrench.

Terminal blocks

The terminal block is a contact plate in a polymer or carbolite housing. With their help, any user can connect wires. The connection occurs in several stages:

• stripping the insulation by 5-7 mm;
• removal of oxide film;
• installing conductors in sockets opposite each other;
• fixation with bolts.

Pros - you can connect cables of different diameters. Disadvantages - you can only connect 2 wires.

Types of terminal blocks for multi-core and single-core cables

There are 5 main types of terminal blocks:

• knife and pin;
• screw;
• clamping and self-clamping;
• cap-shaped;
• "walnut" type clamps.

The first type is rarely used; they are not designed for high currents and have an open design. Screw terminals provide reliable contact but are not suitable for connecting multi-core cables. Clamp terminal blocks are the most convenient devices to use; their installation does not require special equipment. Cap-type devices are also often used, but unlike clamping devices, caps can be used repeatedly. "Nut" is practically not used.

Terminals in junction box (copper or metal)

Terminals are the most common connection method in a junction box. They are cheap, easy to install, provide reliable contact fixation and can be used to connect copper and aluminum. Flaws:

• cheap devices are of low quality;
• Only 2 wires can be connected;
• Not suitable for stranded wires.

Self-clamping terminal blocks WAGO

There are 2 types of Vago terminal blocks used:

• With a flat spring mechanism - they are also called disposable, since reuse is impossible. Inside there is a plate with spring petals. When installing the conductor, the petal is pressed out and the wire is clamped.
• With lever mechanism. This is the best connector option. The stripped conductor is inserted into the terminal and the lever is clamped. Re-installation is possible.

With proper use, Vago terminal blocks last 25-30 years.

Using Tips

For connection, 2 types of tips and sleeves are used:

• in the first, the connection is made inside the product;
• in the second, two electrical wires are terminated with different tips.

The connection inside the sleeve or tip is strong and reliable. There are also special sleeves for connecting copper and aluminum wires.

Soldering of electrical wiring lugs

The tips are connected to the wiring using a press. If it is not there, contact can be ensured by soldering.

The electrical wire and the tip inside are tinned, the stripped cable is inserted inside.

The entire structure on the contact must be wrapped with fiberglass tape and heated with a burner until the tin melts.

Welding

Another way to improve twisting is welding. Again, welding is just a method of increasing the reliability of twisting.

It is not applicable for aluminum wires; welding is used only on large-section copper cables.

Reliability when welding is much higher than when soldering. It is a good way to improve connections in a junction box, but welding is still not very practical.

In addition, it will require special equipment, a welding inverter.

Welding is not used on aluminum wiring; an additional disadvantage is the possibility of weakening the twist, since when the wires are very heated, which will be necessary during the welding process, the twist itself may weaken due to a change in the physical properties of the metal.

Soldering and welding cannot be considered separate connection methods; they only provide additional reliability.

Also, after using a soldering iron or welding machine, the connection point will still have to be insulated.

Important Notes on Wiring Connections

Let us note important points regarding electrical wires.

1. All wires twisted together should not dangle somewhere in the air! They must be placed in a junction box.
2. For all wire connections, ensure that the bare ends of the wires are completely hidden in the connection block. That is, try to make the connection so that after this connection it would be impossible to reach the bare end of the wire with your hand.
3. Do not try to remove the wire from terminals that are not intended for this purpose. For example, there are craftsmen who manage to remove wires from wago terminals. But I do not recommend doing this, since such removal is always associated with deformation of the wire. And this is unacceptable, because the load on the network should be experienced by whole wires, and not half-broken ones, which can lead to short circuits.

This is where the article ends. We have studied in detail the issue of how to connect wires in an apartment. Now, when moving the socket from one place to another, you can easily extend the wires by laying them in the wall and making the correct connection.

They installed these pads for me at home... It would be better if they did everything with twists. The socket doesn't work and that's it. I called an electrician, he immediately said that the problem was in the pads and that they (the problems) would appear periodically. I reached into the box and sure enough: I turned the wire in the block, the socket started working. But problems cannot help but appear: in the block the wires are pressed with thin petals, very similar to steel ones. So I'll look for something else instead of pads...

I’ll honestly tell you that I made all the connections at home through the blocks. The kitchen has a lot of electricity supply: 3 sockets, heated floor. dishwasher, hood, microwave and everything is on blocks that are hidden in junction boxes or sockets.

I don’t argue that there are cases, but these are the exception rather than the rule. There might have been a defective batch. And the examples are very different. Some people's walls fall apart after plastering, while others have had no problems for 25 years. But this does not mean that now there is no need to plaster the walls. Somewhere the technology was broken. Therefore, here we need to study the problem, look deeper into why this is happening. And if twists were the most reliable, then firefighters would not prohibit them.

Hello. I am installing electrical wiring for a mini-bakery. Everything is great except for one thing. The fact is that I am opening a company in a remote corner from civilization in a small village. The city is 2000 km away and only by plane. Therefore, I stocked up on everything in advance. Except of course the wires. And then I somehow found the usual white two-wire and three-core aluminum noodles with a cross-section of 1.5 sq. mm. and copper three-core 2.5 sq. mm. Three-phase electrics. I installed 2-wire noodles for lighting, and three-wire for sockets with chargers. I have only three equipment supplying 380 W. Dough mixer 2.4 kW, Flour sifter 1.2 kW, Oven 19.2 kW. Since there is no choice, all three of them carried out wiring with a cross-section of 2.5 sq. mm. In addition to the stove, the dough mixer and flour sifter work perfectly. But when I turn on the stove after 5 minutes, the RCD 63A 30Ma turns off the electrical supply. I think this is due to the cross-section of the wire because... I found on the instructions that you need to use a wire with a cross-section of 6 sq. mm. How can you get out of the situation? Of course it would be great to find a 6 sq. mm wire. But I only have 2.5 sq mm. Please tell me whether it is possible to use a three-core wire as one wire, i.e. connect all three to one?

Yes. It would be optimal to make all three wires of one wire 1 phase (7.5 sq. mm), another 3-core wire for the second phase, and also for the third phase, also for zero (also 7.5 sq. mm, respectively), and grounding. With such loads (about 60 A), no terminals will withstand (except screw ones. But for myself I wouldn’t risk it), it is necessary to twist, which should be tinned and soldered (use acid-free flux, solder and a simple gas torch + futor (copper tube with a diameter of 25mm, one end is rolled onto a holder so that the solder does not leak out, approximately 3cm deep), or a welding machine and a copper electrode (boil the ends of the twists until all the cores are welded together into a ball at the end).

Operating procedure

Stripping wires
A step-by-step twisting algorithm can be considered using the example of weaving a stranded and monocore cord. In this case, it is better to work using the branching technique:

1. Stripping the area from the end of the conductors - 3-4 cm long with a stripper or a stationery knife.
2. Placing heat shrink on one of the cables.
3. Degreasing sections without insulation with a special agent.
4. Bend the single-core end 180 degrees to further press the twist.
5. Twisting a multi-core cord over a single-core one. It will take 5-6 turns clockwise.
6. Using pliers, grasp the bent single-core tip and press it against the joint.
7. Place heat shrink in place of the twist and fix it using a hair dryer.

The heat shrink should secure the twist tightly.

Methods of connecting wires: procedure for performing the operation

Twisting is considered the most common option for fastening several conductors together. For this method, it is enough to remove the insulation from the current-carrying wires and twist them tightly together.

Important! For maximum reliability of such a connection, it is recommended to remove the insulation material by at least 5 cm. For good contact, the wires are pressed with pliers

The method of soldering two conductors takes a little longer than the previous one, but it is more reliable. The ends of the conductors are coated with tin or rosin, and then carefully soldered. Such fastening does not create much resistance in the conductors.

The welding method is similar to soldering, but requires more care and the involvement of specialists for such work.

Connection terminals are the most popular and advanced option. Similar fasteners are used in switchboard devices and distribution boxes. The convenience of the connection lies in the ability to use current-carrying conductors of various cross-sections and materials of manufacture.

Spring fasteners are not inferior to pads. The method of such a connection is no less reliable, but efficient. With this, everyone can cope with the task of connecting electrical wiring. In home improvement, the use of bolted clamps and connections is practiced. The only drawback of such fasteners is the mandatory and durable insulation. These devices are used to fasten stranded wires and conductors with different cross-sections.

Spring terminal blocks for wires of different sections

Where is electric twisting used?

Twisting of wires is performed to connect them electrically and mechanically. This connection method does not imply the transmission of high power. Therefore, they try to use twists only in low-current circuits and rooms without high humidity.

Connecting cables using twisting

Reliable twisting has the following properties:

1. Low contact resistance. Otherwise the contact will burn out.
2. High mechanical strength. Especially for wires suspended in the air.
3. Tightness of the connection. When exposed to water, the twist oxidizes and burns.
4. Conformity of metals of current-carrying conductors. Contact between copper and aluminum wires is not allowed.

Important! When installing electrical wiring in an apartment, the twists should be placed in junction boxes. This measure will protect the contact from dust and moisture and make it more accessible for maintenance.

Connection between 6 wires

YOU'RE LYING!!!

In fact, INSULTING the members of the forum who have repeatedly and extensively discussed the types of contact connections, for example, RESEARCH Kamikaze, who described the different types of contact connections in the MOST DETAILS of anyone on the Russian-speaking Internet!

This is not to mention VIOLATION of the forum rules which state that before creating a topic you need to read the forum to see if there is a discussion of something that interests you.

Welding, soldering, IDEALLY a combination of them, in extreme cases crimping, if in combination with soldering then also IDEAL, for example, in high-current circuits I solder the NShV(I) tips after crimping from the end, since the classic termination of NShV(I) in high-current circuits is not refers to the best solutions, in the worst case scenario, clamping with two screws at the same time!

To be on the safe side, you can use 4 screws at the same time.

In the link below, in my next message in that topic, a photo where 7 cores of 2.5 mm2 are connected by soldering, I immediately took “on my knees” after reading the message that it is not clear how to connect 7 cores of 2.5 mm2 by soldering, to show that if hands artisans, there is nothing complicated.

Yes:

Flat spring terminals, so-called screwless, self-clamping, produced by WAGO, Weidmuller, Legrand, ABB, Schneider, Hager and other manufacturers, either according to the standards for contact connections, or by common sense, or by the instinct of self-preservation, CANNOT be used in distribution, installation boxes, shields, sockets, about which I have been warning everyone in more detail for a long time on the vastness of the Russian-speaking Internet, for example on this forum in the topic!

In the topic he added that self-clamping, without screw, flat spring terminals CANNOT be installed even on lighting groups with a 1A automatic machine, since they will not withstand the pulse current that the core will withstand! That is, the conductors connected through such a terminal are essentially connected through a FUSED link! Which was subsequently confirmed by the case described on a similar forum in the topic!

Flat spring terminals, the so-called screwless, self-clamping ones, are recommended to be used in stationary wiring only by those who do not understand electrical/fire safety or by INTENTIONAL hacks, since it is many times, and sometimes even orders of magnitude, more convenient and faster to install contact connections!

SELF-CLAMPING, SCREW-LESS, FLAT SPRING TERMINALS ARE WORSE THAN Twisted!!!

Plastic junction box, plastic corrugated wiring behind a suspended, suspended ceiling, in cavities, money down the drain and DECORATION in the fire resistance of the room!

It is optimal to make RELIABLE contact connections behind a suspended, stretch ceiling, in cavities without boxes and to insulate them WELL!

If you make distribution boxes behind a suspended, suspended ceiling, or in cavities, then use steel!

Also, behind a suspended ceiling, especially a suspended ceiling, in cavities, plastic wiring fasteners are not among the best solutions!

MORE RELIABLE and cheaper than plastic wiring fasteners, the remaining cores, flexibility class 1, from the wiring!

Where aesthetics are visible and required, steel reinforcement!

You need to try, from the same cable manufacturer, the sleeves often have different dimensions.

If you spend money on a tool, then on soldering irons, it’s cheaper and there’s a higher chance that it will be useful later in everyday life.

Self-clamping terminal blocks

Self-clamping terminal blocks are a type of conventional terminal blocks. They provide an even faster connection because you don't even need to use a screwdriver.

The contacts in them are spring-loaded, so to connect the cables it is enough to insert the ends of the wires into the holes with the contacts.

During installation, you need to overcome the force of the spring, after which it will press the contact to the wire. It is noted that this method is very convenient for multi-core wires.

Among the disadvantages of such a connection is that the connection is not particularly reliable; it will not be difficult to pull out the wiring from the terminal block. This is especially true for single-core wires with a large cross-section.

A common disadvantage of terminal blocks is the possibility of moisture getting on the contacts, which can lead to their oxidation and damage.

Useful tips from professionals

Twisting of wires as such is prohibited by the PUE, but if it is used in conjunction with other means, it does not contradict anything:

1. Welding. If you simply attach two wires to each other and weld them, you will get a good permanent contact. And if the cores are also twisted before this, the contact area will increase significantly, see the photo below.
2. Soldering. The situation is the same as with twisting, only in soldering there is a main problem - solders, for example the widely used POS-60, do not provide mechanical strength. So if you solder two complex wires side by side and insulate them and hide them in a junction box, then such a connection will of course work. But if the wire moves even a little during operation, the soldering will break. Therefore, always twist the wires if you choose soldering as a method of connecting wires.
3. Use PPE caps. To do this, you need to fold the connected wires together, insert them into the cap and begin to twist the cap clockwise. The spring in it will clamp the veins and they will twist.
4. Clamp the twisted wires with a screw terminal block (they are also called polyethylene terminal blocks).

It is important to note that none of the above options makes the twist waterproof, so if you decide to fasten the conductors under the plaster in the wall, without a box, be sure to insulate the connector with cambrics. That's all you need to know about how to properly twist wires with your own hands.

We strongly recommend that you use more modern methods, and use twisting only when installing temporary electrical wiring! Do not twist under tension under any circumstances, because Today there is no such safe method. Any electrical installation work must be done with the lights turned off!

That's all you need to know about how to properly twist wires with your own hands. We strongly recommend that you use more modern methods, and use twisting only when installing temporary electrical wiring! Do not twist under tension under any circumstances, because Today there is no such safe method. Any electrical installation work must be done with the lights turned off!

Pros and cons of using twists

Despite the risk of fire, twisting is very often used by electricians. This is explained by the advantages that this type of connection has:

• this is the cheapest way to connect wires;
• All you need is a knife and insulating tape;
• ease of manufacture;
• takes up minimal space.

Twisting is the easiest way to connect wires.
There are also disadvantages:

• such a connection is prohibited by the rules of the PUE;
• risk of fire;
• Twisted wires are difficult to separate.

How to connect 3 wires

Quite often a situation arises when it is necessary to connect not two, but three wires, for example, when supplying energy from one phase to two consumers at once, and in such cases, the most convenient method of connection is a mechanical clamp.

Depending on how large the load will be, it is necessary to select the appropriate model of the clamp used. The simplest option is a metal sleeve into which wires are inserted on both sides, on the one hand supplying, and on the other, pre-twisted together, feeding.

If one of the wires has a larger cross-section, then it is this wire that is inserted into the sleeve without twisting. After the wires are inserted, the connection is secured with clamping screws.

If the wires are of small cross-section, then the usual twisting of all three is used; pliers are used to ensure a tight connection. The twisting area can be covered with a plastic threaded cap.

Why is twisting dangerous?

The main danger is high resistance. In addition, if the connection is poorly tightened or gets hot, then this indicator becomes even worse.

The twisting point acts as a low-resistance resistor. Under the influence of current, thermal energy is released on it. It promotes oxidation of the twist and further deterioration of the contact. As a result, the wires connected in this way simply burn out. Often this is what causes device breakdowns and wiring short circuits.

Burnt twist

Let's take a closer look at the types of clamps

There are different types of terminal blocks designed to perform specific jobs. We will now try to consider the most common products.

Screw terminal block

The screw connection remains familiar and popular. The mechanism of the product is quite simple and reliable. Screw terminal blocks can be found on household wiring connections, inside many electrical appliances, and even car battery terminal clamps also belong to this group. But, if the electrical terminal blocks for electrical wiring have a copper or brass jumper inside, then the battery terminals are most often made of lead. This is due to the fact that there is acid inside the battery.

The advantage of screw terminal block models for connection is the high-quality contact of the entire area of ​​the cable core with the metal jumper of the clamp. The screw allows you to easily connect and disconnect the wire. On many screw models you can find a screw marked green. It is used to connect the grounding conductor. The special feature of the clamp is its teeth. When pressed hard with a screw, they cut into the metal, improving grip.

The disadvantage of a screw clamp is that it can only be used with copper wire. You can, of course, clamp an aluminum core, but if you don’t calculate the force, the brittle metal will deform. Another disadvantage is the inconvenience of use. In order to connect many wires with screws, it will take more time than to perform a similar operation with spring mechanisms. When in a hurry, inexperienced craftsmen often completely unscrew the clamping screw and lose it. However, these minor problems do not deteriorate the quality of the screw connection, but the fact that the screw connection can become loose during vibration determines its main disadvantage.

Crimp terminal block

This type of electrical product is intended for connecting cable cores with a maximum permissible current of 24 A. The terminal block attached to the cable can withstand up to 5 thousand volts. With one product you can immediately crimp up to 8 prepared terminals for connection. This design greatly simplifies the installation of electrical wiring. According to the type of fixation, the terminal block can automatically fix the contact inside the socket or mechanically, which is done manually. If you correctly calculate the force when crimping the terminal block, you will get reliable contact.

Product labeled PPE

Such terminal blocks are called insulating and look like a plastic cap. The clip is made of heat-resistant polymer that is flame resistant. There is an opinion that PPE is intended to protect the connection from fire. In fact, the terminal block creates a strong mechanical contact and will withstand voltages up to 600 volts.

The principle of operation is simple. There is a usual twist of exposed wire strands. Moreover, all wires must be made of homogeneous metal. To avoid oxidation, it is advisable to treat the twist with paste. There is a cone-shaped spring inside the plastic cap. This will create a strong connection. The cap is put on the twist, twisting clockwise. At this time, the spring presses the veins in turns, creating a strong contact. If two wires of equal thickness are connected, they do not need to be twisted. The bare ends are forcefully inserted into the cap and rotated. The spring inside will do its job itself.

Power terminal blocks on DIN rail

Power terminal blocks are installed on a circuit board or DIN rail. Their complex design allows you to connect wires of different thicknesses up to 300 mm 2. connect aluminum wire with copper, and also simultaneously connect cable cores designed for different power. The power terminal blocks have a tinned copper plate, to which the wire is pressed with a special conical washer, which does not allow the connection to loosen.

Universal and Barrier Clamps

These products have a special design feature - a metal plate. It is divided by cells of insulating material. The cell jumpers prevent the wires being connected from touching. Reliable fastening of the cores is ensured by screws. On metal terminals, aluminum wire practically does not oxidize, which allows the use of such terminal blocks without restrictions. Most often, the connections of wires in the distribution box are made using barrier clamps.

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Preparing for twisting

Before twisting, it is necessary to remove the layer of protective insulation from the current-carrying conductors. Usually this operation is performed using a knife. During operation, you should try not to damage the metal current conductor with the tool blade. Otherwise, it is capable of breaking in a weak spot. This is especially true for soft stranded cable cores.

If you are going to remove the insulation from an aluminum cable, you must avoid kinking it. This metal does not cope well with frequent deformations. Therefore, an aluminum cable can break during stripping.

Removing the insulation from the cable

Note! Aluminum wire can break even under insulation. This usually happens within 20 cm of the connection. This problem cannot be identified visually. The break is looked for by touch.