Connection of wires. Twisting, soldering, welding, crimping, Wago terminal blocks

When installing electrical wiring in a house or apartment, connection of wires - the most important point . For trouble-free and safe power supply, you will need a reliable and high-quality connection of wires.

A careless attitude towards connecting wires and cables can lead to very bad consequences. It would seem that there is nothing complicated in connecting the wires, twist them, wrap them with electrical tape and everything is ready, but everything is not so simple... as popular wisdom says "Electrics is the science of contacts", and the connection of wires and cables must be carried out with all responsibility, since the percentage of accidents and damage in power supply systems due to poor-quality connection of wires is very high. No matter how good the electrical contact between the wires is, wire connections have higher resistance, which means they heat up more. And the worse the contact, the more it heats up, which will ultimately lead to melting of the insulation, short circuit, and then a fire.

In practice, several methods of connecting wires are used, I will tell you about the most common ones.

Connecting wires by twisting

Connecting wires twisted, widespreadeverywhere, but if we turn to the main book of electricians PUE, then according to:

clause 2.1.21 “Connection, branching and termination of cables and wire cores must be done by soldering, welding, crimping or clamping (screw, bolt, etc.)”

As we can see, there is no twisted connection of wires at this point, which means twisting of wires is prohibited. But twists have always been, are and will be used to connect wires when installing electrical wiring. Yes, and well-made twisting can last for decades, but the connection of wires by twisting must be done efficiently. The technology for connecting wires and cables by twisting is quite simple:

the length of the twist must be at least 4-5 cm;
The connected wires, stripped of insulation, must be cleaned of the oxidized film, for example, with an ordinary knife or sandpaper;
It is necessary that the connected wires wrap around each other evenly and tightly, ensuring sufficiently reliable contact.

One “but”, problems may arise when handing over the electrical installation to the fire inspectorate, because... Connecting wires by twisting according to the PUE is prohibited. However, this applies mainly to industrial consumers, retail premises, etc., in your apartment or a private house the fire inspector will not come to check.

Connecting wires by twisting- This necessary measure , when there is nothing else left, it is better to use wire connections using the methods described below.

Connecting wires by soldering

If solder twisted wires, then we get the connection of wires soldering, which guarantees reliable and high-quality contact, which has a fairly low contact resistance, high conductivity and mechanical strength. But it is important to solder the wire connection correctly; for this you need:

tin the connected wires with rosin (flux);
the solder should flow into the twist;
After the solder has cooled, you can sand it with sandpaper, because sharp edges of the solder can pierce the insulation;
insulate the wire connection.

But such connection of wires by soldering is very labor-intensive and requires certain skills. TO negative sides of soldering wire connections, I would classify:

need for isolation;
complexity (not everyone knows how to solder well), and even for those who are good at soldering, doing this, for example, while standing on a stepladder or ladder, to put it mildly, is not very convenient;
if a mistake was made when connecting the wires, it will not be easy to separate them after soldering, so it is better to leave a larger supply of wires and cables;
high time consumption.

Connecting wires by welding

Connecting wires welding provides even better electrical contact between wires. But here everything is even more confusing than with soldering wires, since you need to have:

welding transformer;
welding skills;
masks (goggles) for welding, special gloves, electrodes;
construction hair dryer for heat shrink tube.

Wire connection by welding, you can perform only from homogeneous metals. Such a connection of wires can be found rarely, our people do not really like difficulties, and many electricians do not like this method of connecting wires because high costs time, but it’s worth noting that connecting wires by welding is faster than soldering.

Connecting wires by crimping

Connecting wires crimping, consists of compressing the connecting sleeve (aluminum or copper tube) into which the wires are inserted with special press pliers. The wires are first stripped of insulation to the length of the sleeve, then we place the wires inside the sleeve and crimp it in two or three places for reliability. If the sleeve is much larger than the wires that need to be crimped, then you can stuff the sleeve with additional wires. We insulate the resulting wire connection by crimping electrical tape, or better yet heat shrink tube+ hairdryer

Sleeves for connecting wires by crimping, there are copper, aluminum and copper-aluminum, i.e. Crimping can be used to connect copper and aluminum wires.

Connecting wires using crimping is quite reliable if done correctly. Skills in connecting wires using crimping will also be useful to you when, for crimping NShVI bushings.

The disadvantages include the cost of pressing pliers for connecting wires by crimping and sleeves, the inseparability of connecting wires by crimping, i.e. they crimped the wire in the sleeve and “forgot” about it.

Bolted connection of wires and cables

Bolted connection wires, as a rule, are used when connecting wires made of different metals, that is, if we have one wire made of copper and the second of aluminum, a steel washer must be placed between them.

This connection of wires turns out to be very cumbersome, it is inconvenient to place it in junction boxes and insulate it. Periodic broaching is required.

Connecting wires with screw terminals

Connecting wires screw terminal blocks, as well as bolted, can be used to connect wires made of different metals. This wire connection meets the requirements of the PUE, but requires periodic tightening of screws in terminals that weaken over time, which means the contact itself weakens, which can close over time.

Periodic pulling the screw connection of wires involves, What connection access in the box should always be open, which will not look very nice in an apartment or private house. Also, when tightening the screw, you can damage the wire itself, especially the softer aluminum one. And if you need to connect a stranded wire, then you need to either solder the stripped ends of the wire or crimp it with tubular lugs.

Connecting wires with PPE caps

Connecting wires PPE caps(Connection Insulating Clamps). PPE are plastic caps with a conical spring inside, which, when twisted, compresses and fixes the wires, and the plastic PPE cap itself insulates the connection of the wires and is fire and mechanical protection.

This connection of wires is quick and simple, for its correct execution necessary:

strip the insulation from wires and cables to a length slightly shorter than the length of the PPE cap itself;
fold them into a bundle, precisely into a bundle, and not twist them;
use your hands to twist the PPE clockwise onto the bundle of wires;
tighten the PPE using pliers.

The advantages of such a connection wires and cables are obvious (no special tools required, no need for additional insulation, quick and easy), but there are also disadvantages:

Do not connect multi-wire wires;
the quality of such a connection will be worse than those listed above, so I would recommend using these clamps for small loads, for example, in lighting circuits.

PPE caps are divided according to the total cross-section of the wires to be twisted and are designated by numbers from 1 to 5, which indicate the number of wires to be twisted and their cross-section.

Connecting wires with self-clamping (spring) terminals

Well, in conclusion, let’s consider the simplest, most effective, convenient, and most importantly fast connection wires – self-clamping (spring) terminals. Spring terminals from Wago are widely used, which allow you to connect wires:

without having any special skills;
no need to purchase special tools (soldering iron, welding transformer, press jaws);
some Wago terminals have a special paste that allows you to connect copper and aluminum wires and prevents oxidation;
no additional insulation required;
quick disconnection of the connection (press the lever and pull out the desired wire).

Wago terminals are produced for connecting wires and cables from 0.75 to 4 sq. mm, the number of connected wires is from 2 to 8. Wago terminals

Wago terminal blocks were invented in Germany. Perhaps the most significant disadvantage is their price, average cost a Wago terminal block for 3 wires will cost approximately 11-12 rubles, so if there are a lot of distribution boxes, then the total cost of Wago terminal blocks will be considerable. You should not use Wago terminals when installing wiring with loads of more than 16 A. In general, it is better to use them maximum on the lighting line for electrical wiring in a private house or apartment, and choose Wago terminal blocks with a margin of at least a step higher.

Junction boxes perform a very important function. They ensure the distribution of electrical wires between points of consumption, i.e. switches, lighting fixtures and sockets.

Have you decided to install the devices listed above yourself? Then you need to thoroughly understand the features and order of connecting cables, as well as the basic methods of connecting them.

For a better understanding of the process this event will be considered in several stages: from preparation necessary materials before connecting electrical appliances using the example of a socket, two-key switch and light bulbs. First, you will learn about the basic methods of connecting cables and wiring features

Wire connection methods

There are several methods for connecting electrical wires. You can choose the most convenient and suitable option for your case.

Prices for cables and wires for construction and repair

Cables and wires for construction and repair

The first stage - getting ready for work

First of all, we prepare everything that is needed to connect electrical appliances to the box. Set includes:

cables 3x2.5, VVG;
cables 2x2.5, AVVG;
switch with 2 keys;
fastenings;
lighting;
socket;
round nose pliers;
roulette;
wire cutters;
pliers;
flat screwdriver;
hammer.

Second stage - make the markings

At this stage, we mark the installation locations of electrical appliances and the routes for wires. So we can calculate required quantity materials for system installation.

The third stage - we begin installation

First turn off the electricity supply.

We connect the wires to distribution box. As a rule, cables are laid in grooves. Small nails or special plastic staples are used to secure the cables. If work is performed in wooden house, the wires will be supplied through special mounting boxes.

Important note! You should try to lay the wiring so that the cables do not intersect. If intersections are unavoidable, such places must be isolated especially carefully.

The fourth stage - we connect electrical appliances and connect the wires

We insert approximately 10 cm of wire into a distribution box pre-built into the wall or fixed to the base (depending on the model). We remove the general sheath from the cables. Then we remove approximately 0.5 cm of insulation from each core. At this point, we focus on the situation - we remove enough insulation so that the cores can be connected in the chosen way.

The diagram shows an example of connecting electrical wires using terminal blocks.

In the example under consideration, the connection is made using a two-wire wire, in which one wire is a zero, the second is a phase. We connect the socket to zero and. We connect the phase supply wire to the socket and one core of the switch cable.

In our example, the switch is two-key. Each key is responsible for control separate group lighting fixtures. We connect the second wire of the switch cable to the first button, the third wire is connected to the second button.

The distribution box contains the neutral wires from the socket and light bulb sockets. The power cable is connected: zero is marked in blue, phase is marked in red. Wires are connected to connect each switch button to the light sockets.

Fifth stage - checking the functionality of the system

We turn on the power supply and check the operation of our outlet and. Everything works fine. We did a great job.

Now you know the order of connecting the wires in the junction box and the connection features of each main electrical appliance. Using the information received, you will be able to independently cope with all planned events.

Good luck!

Video - Connecting wires in a junction box

Not only the reliability of the power supply, but also the safety of housing depends on the quality of the wire connection. Damage to the wiring occurs due to poor contact at the connection point, as a result of which it burns out, and in the worst case, causes a fire.

The method of connecting wires is selected depending on:

Wire material.
Sections of veins.
Wiring operating conditions.
Number of conductors.

All connections are made according to the diagram in the distribution box, which is installed hidden or open method.

Connection with terminal blocks

The terminal block design consists of a plastic housing, inside of which there are brass tubes with threaded holes on both sides. The diameter of the inlet holes of the tubes varies and is selected depending on the cross-section of the wire.

The process of connecting wires in this way does not cause difficulties even for beginners:

Select a block with the required cell size.
Cut off required amount sections.
Remove 5 mm of insulation from the conductors and clean the surface of the conductors.
Insert the ends of the wires inside the cells and secure by tightening the screws.

The last procedure is carried out with force, especially if aluminum conductors are used. If too much force is applied, the screw will crush the aluminum core, the same applies to stranded wires - thin wires are deformed under the action of the screw, making the connection unreliable.

This problem is solved by special lugs that are placed on the bare ends of the wires, crimped with press jaws or pliers, and then inserted into the cells of the terminal blocks. To connect aluminum or stranded conductors, terminal blocks made of high-strength plastic are also used, in which the conductor is clamped not with a screw, but with a plate, thereby achieving reliable contact. The devices are designed to operate with higher current.

Advantages of terminal blocks:

Low cost.
Quick installation.
Good connection quality.

Flaws:

There are many poor quality products on sale.
You cannot connect more than two conductors.

Terminal blocks are convenient to use for connecting chandeliers, sockets, switches, as well as joining wires broken in the wall, but such a connection cannot be hidden under a layer of plaster, but only in a junction box.

Spring terminals

The design of spring terminals was developed by the German company WAGO. The principle of their operation is that the conductors are clamped not with a screw, as in conventional terminal blocks, but with a lever-type mechanism that fixes the conductors without deforming them.

WAGO terminal housings are made from polymer materials. The contact part consists of two brass plates, one is rigidly fixed, and the second is movable. Simply insert the bare end of the wire into the terminal cell and lower the locking flag.

There are two types of WAGO spring pads:

Detachable.
One-piece.

Detachable terminals are reusable - the connection can be disassembled and reassembled. Permanent terminals are used only once. To repair the wiring, you will have to cut off the terminal block and install a new one after fixing the problem.

Advantages of spring terminals:

Quick installation.
Connection of more than two conductors.
Reliable contact without deformation of cores.
Hole for measuring network parameters.
You can connect conductors from different materials.

Flaws:

High cost compared to conventional pads.
Not recommended for use on heavily loaded networks.

Important. When connected aluminum wires It is recommended to pre-fill the terminal with contact paste to prevent oxidation of the wires. WAGO's product range includes terminals that have already been treated with this product during manufacture.

PPE caps

The design of connecting insulating clamps (PIC) consists of a cap and a cone spring inserted inside it. The cap is made of heat-resistant plastic that can withstand voltages up to 660 V.

Connecting wires with PPE caps is done in two ways - with and without preliminary twisting of the cores. When connecting two conductors, it is enough to attach their bare ends to each other, put on the cap and rotational movements twist clockwise. Connecting three or more wires with a PPE cap is done by twisting their ends with pliers. The insulation from the cables is removed so that the exposed part does not protrude beyond the cap - additional insulation is not required.

Advantages of PPE caps:

Low cost connectors.
Quick installation.
PPE is made of non-flammable material.
The caps have different colors, which makes it possible to mark the wiring.

Flaws:

Do not connect copper conductors to aluminum ones.
Relatively weak fixation and insulation.

To make the connection reliable, it is important to choose the right type of clamp. All PPE caps are marked, which first indicates the type of body: 1 - without a protrusion, 2 - with a protrusion for more convenient grip of the cap with your fingers. After the housing type, the minimum and maximum total cross-section of the cores that can be connected in the clamp is indicated.

Crimping with sleeves

The most reliable connection, used in lines with high current load. A tube is used as a clamp, into which the bare ends of the conductors are inserted and crimped with mechanical or hydraulic press pliers. Some craftsmen use pliers for this purpose, but in this case the reliability of the connection cannot be guaranteed.

The material of the sleeve must match the material of the conductors. If it is necessary to connect a copper cable to an aluminum cable, use a combined copper-aluminum sleeve. The diameter of the tube is selected depending on the total cross-section of the conductors - after inserting the ends, there should be no voids left in it.

The connection of the wires by crimping is done so that their ends are approximately in the middle of the sleeve. The connection is insulated with heat shrink tubing or ordinary electrical tape.

Advantages of crimping with sleeves:

Low cost of sleeves.
Reliable connection with high mechanical strength.
You can combine copper with aluminum.

Flaws:

Permanent connection - if necessary, the sleeve will have to be cut off.
Needed for work special tool.
The work requires more time.

Important. Copper and aluminum are susceptible to oxidation. Before crimping, it is recommended to clean the wires to a shine and treat them with a special lubricant.

Soldering and welding

Soldering is an old but reliable method that is still used today. Its essence is to connect wires with molten solder, which flows into the twist gaps. After it hardens, a monolithic compound is formed. Soldering is used for joining copper wires. There are also fluxes for aluminum on sale, but experts prefer to refrain from soldering it. Soldering process:

Remove the insulation from the ends of the wires and remove any varnish.
Make a twist.
Treat the twist with rosin.
Heat the joint with a soldering iron and solder until it fills all the gaps.
Let cool.
Treat the soldering area with alcohol and insulate it.

This method is well suited for joining conductors of small diameters. The resulting connection does not require maintenance throughout its entire service life.

Advantages of soldering:

Excellent connection quality.
Low cost of work.

Flaws:

Labor intensity.
Experience with a soldering iron is required.
Permanent connection.
Cannot be used in networks with high current load.

To connect cables by welding, a welding machine is used. As in the previous case, the ends of the conductors are pre-twisted, then the end of the twist is fused with a carbon or graphite electrode until a ball is formed. The result is a monolithic connection that is reliable. The disadvantages of this method are the permanent connection and the need for certain welding skills.

Stranding and insulation

The idea is to twist the bare ends of the conductors together with pliers and then insulate them. Until recently, when the load in apartments consisted only of lighting and TV, twisting was used everywhere. Now it is prohibited by PES, especially in wooden buildings and rooms with high humidity.

Advantages of twisting:

Ease of operation.
No material costs required.

Flaws:

Poor connection quality.
Copper cannot be combined with aluminum.

Preparatory stage for soldering or welding, when installing temporary wiring.

Connecting wires with walnut clamps

Branch clamp is designed to make branches from the main cable without breaking it. The clamping device consists of a collapsible polycarbonate body; inside there is a steel core of two dies and an intermediate plate. The body halves are connected to each other by retaining rings, and the dies are connected by coupling bolts.

Branch compressor installation:

Disassemble the branch compressor.
Remove the insulation from the main wire to the length of the plate.
Strip the end of the outgoing wire to the length of the plate.
Place the wires in the grooves on the dies.
Tighten the core with bolts, first placing a brass plate between the dies.
Assemble the body.

Important. It is necessary to choose the correct standard size of the “nut”, depending on the cross-section of the cables used. The selection of compressions is carried out in accordance with the range of sections indicated on the core plates.

Benefits of nut compression:

Low cost.
Easy to install.
Possibility of connecting aluminum and copper.
Good insulation.

Flaws:

Large dimensions of the device.
It is necessary to periodically tighten the bolts.

The device can be used in networks with voltages up to 660 V. The “nut” body has enough good insulation, but is not able to provide complete protection from moisture and dust. When using compression in unfavorable conditions, it is recommended to wrap the body with electrical tape.

Bolt connection

All you need for the job is any bolt, washers of the appropriate diameter and a nut.

The ends of the conductors are stripped of insulation. In exposed areas, loops are formed along the diameter of the bolt. To make work easier, the ends of the cables can be wrapped around the bolt and then tightened. The connection elements are put on the bolt in the following order:

Washer.
Conductor.
Washer.
Conductor.
Washer.
Screw.

The nut is tightened by hand, then with a wrench or pliers. The finished connection is carefully insulated.

Advantages of bolted connection:

Ease of operation.
Reliable contact.
Low cost.
Demountable connection.
Use in networks with high load.

Disadvantages: bulky design, which cannot always fit into a junction box, high consumption electrical tape.

How to connect multiple wires

The following methods are suitable for combining wires:

Spring terminals.
Twisting with soldering, welding or using PPE caps.
Crimping with sleeves.
Bolted connection.

The first option is less labor-intensive and the fastest. Also suitable bolted connection- the number of conductors is limited only by the length of the bolt, but the connection has large dimensions.

Connecting wires of different sections

When connecting conductors of different cross-sections, twisting cannot ensure reliable contact, so all methods associated with it are excluded. It is recommended to use terminal blocks, spring terminals or bolt connection.

Combining stranded and solid conductors

Doesn't have any special features. Any of the described methods will do, with the only exception being twisting of conductors from different materials. Otherwise, the choice depends on preferences and financial capabilities. When using screw terminal blocks, it is necessary to have lugs on the stranded wire.

Connecting cables in water and underground

Electricity and moisture are incompatible, so connections made underwater or in the ground have special requirements. The ends of the conductors are connected by soldering or crimping with sleeves. Then they are treated with hot melt adhesive and insulated with heat shrink tube. If everything is done correctly, then moisture penetration into the joint is excluded.

You can also use terminal block connections. The connection point is placed in a sealed box and filled silicone sealant. The cable running underground must be placed in a pipe or box to prevent damage by rodents.

You can use one method or several at once - it all depends on the installation. The main thing that should not be forgotten is safety. The area where they are produced electric installation work, necessary in mandatory disconnect from the network, adhere to the rules and use a working tool.

Knowledge modern technologies and methods of working with electrical fittings, is it really necessary? Yes, how to connect correctly electric wires need to know.

This can be useful during installation and installation of any power supply systems. Is the wiring burnt out and needs replacement? lighting fixture or installation of new equipment. Such knowledge may not be necessary, but it would be better to know all the common methods of connecting electrical wires

Application in terminal block circuits

Terminal blocks are electrical products made of non-conducting material, inside of which a conductive sleeve is inserted, which has a pair of screws at opposite ends. They serve to secure the wire. An excellent choice for implementation modern way wire connections.

When choosing a reliable connection of wires, it is important to remember: terminal blocks are produced with different holes for many cross-sections.

This method is almost always used for connections in junction boxes of any type, during installation, installation of wall and other lamps. It is suitable for. It is easy to mount a network using such fittings; you just need to insert the bare ends into the holes and, using moderate force, securely tighten the screws. The wire itself should not be crushed. Having figured out how to properly connect electrical wires using terminals, it is worth exploring other equally reliable methods.

Terminal method rating: Excellent fastening quality. Their prices are reasonable. Quite quick and easy installation. A good opportunity to connect different conductors, for example, aluminum and copper.

It is not recommended to connect aluminum and stranded circuits with blocks. This is due to the high fragility of aluminum wires and the great flexibility of the conductors themselves. stranded wire. But overall a decent method.

Spring terminals

Quick installation of electrical networks is sometimes simply necessary. For example, install temporary lighting on a balcony, terrace, gazebo. wago spring terminals, great product for conducting similar works. Modern and of course reliable way wire connections. Although they are new to the electrical accessories market, installation using spring terminals is quick and, importantly, convenient.

The main difference between the use of the Vago terminal blocks themselves: they are more convenient to connect any wires in electrical boxes than with twisting. Here, for high-quality installation, a unique clamping mechanism is used, rather than a simple screw. Manufacturers produce both disposable and reusable vagon systems.

In its normal version, this product is used for one-time use, with repair work it cannot be restored subsequently. It is removed and a new one is installed in its place.
Wago reusable terminals are a little more expensive, but with their help you can disconnect the assembled contacts several times, rewiring the circuit to suit your needs. This speeds up the process of repairing or installing permanent and temporary networks. A simple lever-type mechanism provides the advantage that it is possible to carefully but efficiently fix any wire without damaging or squeezing it.

With the help of a vagon, it is easy to carry out the fastening yourself; you just need to strip the insulation and insert required cores V mounting hole. Press the lever. It's important to get it right.

Wago Clamp System Rating: Unique opportunity combination of any aluminum, copper and other conductors. There is an option for connecting multi-core cables simultaneously (two or more).

Wago universal clamps allow you to fix any thin stranded conductor without damaging it. Another plus is the compact size of the pads.

Wago self-clamping terminals

Excellent quality and durability. The Vago type block has a technological hole that provides access for a screwdriver with a voltage indicator. The operation of any power line can be checked at any time. Perhaps one drawback is the considerable cost of the terminals themselves. But this type of wire connection is the most modern and fastest.

Isolation with PPE caps

Deciphering the product is not difficult, connecting insulating clips (PPE). They are ordinary nylon or plastic caps with an internal lock.

The simplest type of connection of wires, it is carried out after twisting the conductors themselves, the cores. Caps are often used to connect wires in junction boxes and to mark connections with the desired color.

Evaluation of the use of such products: Quite low cost of PPE. Application safe material prevents ignition of electrical wiring. Easy installation, put it on a twist of wires and everything is ready. These caps have a large color scheme, which is convenient. Of course, if the wires are not color coded, colored PPE has the ability to determine or simply mark zero, phase and other necessary electrical routes.

There are also disadvantages: Insufficient level of fixation. Multicore wires can be installed only after soldering.

Installation of networks using sleeves

This option claims to be the most reliable connection method. Any load and quality of wires.

Crimping wires with sleeves

The conductive wires are inserted into a special tube - a sleeve, and crimped with a certain force. There is one thing, but. The cross-section of the wires should not exceed the cross-section of the mounted sleeves. Having inserted and crimped the clip, the sleeve is carefully insulated with heat-shrinkable tubing or other insulating materials.

Overall rating. Great way reliable connection of wires. The direction of the conductors can be with various sides tubes or on one side. The sleeves are quite inexpensive. A good way to reliably connect wires to each other.

There are also disadvantages. Single use sleeves, they are not collapsible. To carry out such work you will need a tool: pressing pliers, which are also used as a special tool. They remove the insulation. They have a crimping device in their arsenal, and electrical installation work takes a little longer.

Soldering or welding wires

This method is reliable. Typically, this method of connection in a junction box involves first stripping and twisting the ends, after which they are dipped into heated solder. It is advisable to connect aluminum to aluminum wires by soldering. They are then insulated using a heat pipe or insulating tape.

Evaluation of the soldering method. It gives strong chain contacts and excellent quality, not expensive, it is the most reliable method of connecting electrical wires in a soldered box.

Technological disadvantage. You can't do this without a soldering iron. The speed of work is not high. The connection is naturally not detachable. It follows from this that soldering is done in extreme cases, using more modern methods connections. It has not been popular among masters for a long time because it takes more time.

There is also a less common method for connecting electrical wires, welding. The process is similar, but requires the use of special welding machine, naturally, and certain skills.

Contact twisting method

Not a new, one might say “old-fashioned” method, it consists of spiral twisting of the cores among themselves. The essence of all work is to twist the stripped conductors using pliers, and cover the twisted area with insulation. These are, perhaps, all the ways to twist wires.

Evaluation of this connection method. High speed of all installation work. The cost part is minimal.

Flaw. It is prohibited to connect together strands of different compositions, copper and aluminum wires., oxidation is inevitable. According to the regulatory framework, it is not recommended to use twisted wires in a junction box in rooms with flammable materials, high humidity, basements, as well as in any house built of wood. More details about the twisting method. I definitely recommend watching a video about which is better: twisting or Vago terminal blocks.

Wire clamp "walnut"

Such a device is simply a cable clamp that has two plates inside and several screws for tightening, usually in the corners. It is enough to screw the wires to the plate itself. Then put a carbolite shell on top.

Grade. An excellent option for connecting any electrical wires in a large and medium-sized junction box. Definitely, these types of products are quite convenient and have a high degree of protection. Makes it possible to quickly connect a wire to a thick gauge track without tearing it.

Flaws. Dimensions allow installation only in spacious distribution boxes and switchboards. Over time, the screws loosen.

Tip: When choosing fittings and method, remember the following:

It is necessary to work only with isolated tools and use protective equipment.
Be sure to post a “do not turn on” warning sign on the shutdown panel or meter.
Connect electrical appliances according to the attached instructions.

Having considered the main types of wire connections, you can easily select the right option. And having a simple tool and a diagram at hand, you can mount it yourself. In details

Content:

Connecting wires is most likely the most common task in electrical engineering. Since for one reason or another there is a lack of length of conductors in electrical circuits, it is necessary to connect their parts together. Obviously, this creates contact, which is the root of many electrical problems. And it is not the electrical connections at a specific location on the conductors that are implied in this case.

If the contact is made correctly, the electrical circuit will function properly. But, nevertheless, the phrase “electrical engineering is the science of contacts” has long sounded like a byword. Later in the article we will talk about how to correctly connect the wires so that this connection does not create problems for as long as possible. As well as a number of other issues that are essential for twisting wires and covering other types of their connections.

Twisting, which the PUE is silent about

In addition to the frequently mentioned words about contacts, among electrical workers there is another common phrase that the work performed by electricians and miners is often very similar in its lethal consequences. In particular, for this reason there is a PUE - essentially a set of laws for everything that has to do with electrical networks. Let's take an interest in the Electrical Installation Rules about how the wires should be connected.

On the one hand, everything is clearly stated:

crimping;
welding;
soldering;
squeezes -

and these are the four officially acceptable ways to connect the ends of conductors. But they all require something additional from tools or equipment, and in some cases quite complex, because:

for crimping you will need a special tool that matches the conductors being connected;
welding is impossible without a welding machine;
for soldering, you must have a soldering iron, as well as the suitability of the material of the connected cores for soldering;
clamps require the use of a special electrical wire connector designed for this purpose.

However, to ensure the connection of electrical wires, you can simply twist their wires together, thus obtaining electrical contact. And, despite the fact that twisting is not specified in the PUE, the very compressible reliable connection of wires, especially approved in in the prescribed manner, fully corresponds to the letter of the electrical law PUE.

In order for the wires to be twisted reliably, the following conditions must be met:

the length of twisted conductor strands from the edge of the insulation to the ends is 40–50 mm;
electrical wires, or rather their contacting conductors, are cleaned with fine-grained emery or a file in order to remove oxide films or insulation residues. You can also use a knife. In this case, movements must be made along the vein. After stripping, it is recommended to evaluate the quality of film removal using a magnifying glass. This will create the best electrical connection;
In order to properly connect wires without soldering, the twisted ends of the wires must be formed using one of the generally accepted methods. They should be pressed against each other as tightly as possible anywhere in the twist.
The types of twists used are shown below. These images will help our readers understand how to properly twist.

What is wrong with twisted wire connections and why is it not explicitly mentioned in the PUE? After all, other methods of connecting wires are noticeably inferior to it in ease of installation and minimal cost, for which such a connection of two wires with one core, as well as twisting multi-core wires, is ahead of all. Other methods of connecting electrical wires remain far behind it.

Main disadvantage twist consists in its weakening over time as a result of repeated temperature expansions conductors.

Gradually, due to temperature deformations of the cores, the force pressing them together weakens, and the contact resistance increases. For electrical circuit wires containing low-power consumers such as energy-saving and LED lamps, the weakening of the contact force will not be dangerous. But for twisting wires in a circuit with electric heating devices with a power of several kilowatts, from a certain moment an avalanche-like process of deterioration of contact between the twisted conductors can begin. Moreover, if such a wiring connection is not noticed in a timely manner, best case scenario either copper wires or aluminum wires, the cores of which are twisted, near it will suffer from damage to the insulation high temperature.

For this reason, the use of twisting in areas with increased fire hazard is prohibited. In these rooms it is necessary to use a more reliable connection of wires.
Twisting of copper wires with aluminum conductors is not permitted. Just as in any other connection, direct contact between the copper and aluminum cores is not allowed in twisting due to the occurrence of electrochemical processes leading to rapid deterioration of the connection and reinforcement fire danger.
It is not recommended to reconnect two wires that have been twisted. Only straight strands are twisted after stripping the insulation, and straightening usually breaks even the strands of a stranded conductor.
Correct twisting can only be achieved for relatively thin conductors. It is not recommended to twist thick single-core wires. To connect wires to each other with a significant thickness of wires, it is better to use crimping them with a sleeve.

Starting from a certain core diameter, it is not possible to twist the wires at all. An example could be power cable. Therefore, the twisting of a cable containing 2, 3 or more cores is made thin copper wire as preparation for a “clean” connection. Then each pair of fixed wires is soldered.

Twisting is half the battle

However, the experiment that was carried out with twisted stranded conductors, showed high quality contact of all wire connections immediately after completion of installation. Made a hundred twists of sections of stranded copper wire with a cross-section characteristic of ordinary apartment electrical wiring, showed very low contact resistance, which is confirmed by the images below.

Consequently, after twisting, you do about half of the installation work of connecting two conductors. It still remains to refine the resulting connection so that it does not deteriorate over time. And to do this, you need to either create a force that compresses the twisted wires from the outside, or use one of the methods of merging the wires. Merging of conductors is, of course, the best way to ensure minimum resistance at the junction of two, three or more conductors.

The connection of wires by merging the cores is done either by melting them or by soldering them. In any of these options, the lowest value of contact resistance is achieved. But these methods also have significant drawbacks. Both during welding and soldering, the conductors are heated to a temperature that is dangerous for the insulation.

In order not to spoil it, it is better to hold the twist with pliers immediately behind the edge of the insulation to dissipate heat during welding or soldering and for some time after completion.
Although there is technology for welding and soldering aluminum conductors, it is still better to deal with copper. But before soldering or welding, the copper core is also cleaned of foreign deposits and degreased.

Welding and soldering eliminates the very concept of contact at the end of the twist, making in this place either a body in the form of a drop (when welding), or filling all the cracks with solder. When connecting wires intended for powerful electrical appliances, welding and soldering are the most The right way conductor connections. However, the experiment, which was carried out on hundreds of twists already shown, did not demonstrate a significant decrease in contact resistance. This is evidenced by the images shown below.

The images provide clear evidence of the same joint properties between conventional and welded stranded wires. But with increasing thickness of the cores, as well as for thick single-core wires, soldering and welding will have an advantage over twisting. If the wires can be connected by twisting, and there is no powerful electrical equipment connected to them, it makes no sense to solder them, much less weld them.

Plug-in connections

The experiments discussed above testify in favor of mechanical fixation of twists. For this purpose, along with sleeves, there are special PPE caps. They make it possible to splice wires, compressing the twist and maintaining the compression force. These are two types of compressions mentioned in the PUE. The first is the sleeve, and the second is the cap. It is screwed all the way onto the stripped conductors. The device, as well as possible types of PPE caps, are shown in the images below.

The abbreviation SIZ reads as:

C – connecting;

I – insulating;

Z – clamp.

Number 1 (SIZ-1) indicates a cap with grooves, and 2 (SIZ-2) indicates the same part with protrusions. Numbers separated by a hyphen indicate the range of wire cross-sections connected to the PPE. The cap is very convenient in that with its use, not only good conductivity of the connection is achieved, but also the ability to separate it. If you need to choose how to connect the conductors to each other, for home and office electrical networks, PPE is best option.

Fast and convenient device, complementing the separable types of conductor connections, is the terminal block. However, its convenience is limited by the load current characteristics. In comparison with the PPE cap, which improves contact resistance, the terminal block worsens it. And it’s very noticeable. To obtain relevant data, a third experiment was made, information about which is shown below. The welded twists were cut off. The ends of the wires are inserted into the terminal blocks.

The contact resistance of the terminal block is an order of magnitude greater than that of the twist.

But it is not only the most acceptable solution for connecting low-current electrical wiring in an apartment and office.

The terminal block is a connecting element between wires with copper and aluminum conductors.
It is convenient to use for connecting wires with different cross sections.
For copper conductors, it is recommended to apply contact paste before inserting them into the terminal block.
Aluminum conductors must be cleaned of oxide film before inserting into the terminal block.

Three types of these connectors are used:

In order for the wire to be inserted into the terminal block without effort and, if necessary, just as easily removed from it, a design with a lever is used, which creates a force in the connection to fix the core. WAGO terminal blocks and their analogs are made on this principle.

A very common type of compression is the screw connection. The designs of many terminal blocks, connecting blocks and sleeves are based on this connection. Screw connection allows you to obtain the greatest force compressing the connected cores. But in order to ensure that such a connection does not weaken over time due to vibrations and temperature deformations, a force is applied to it using a spring, which creates a holding voltage.

Screw clamps are the most effective connection of a single-core wire with a stranded wire, wires of different diameters, including aluminum and copper.
Since screws, nuts and washers are always available to everyone who has connected their profession or hobby with technology and works with their own hands, if necessary, connecting two wires with their help will not be difficult. However, this is done according to the rules that are illustrated in the image below.

When using screw clamps, it is necessary to remember that the quality of contact is primarily determined by the area of the contacting surfaces. And it decreases as the core diameter increases. In this case, no efforts of screw clamps will help. For large core diameters, contact pastes and gels must be used. But in this case, soldering and welding will still provide more reliable contact than a screw connection.

Correct connection of wires is the key safe work electrical networks. We must not forget how to twist correctly, choose the optimal type of connection, and also perform it correctly.