Today, there are many ways to connect wires in a junction box.
Here are the factors that determine the choice of connector:
- Core material (copper or aluminum).
- Working conditions (outdoors, in an apartment, in water, in the ground, in the floor, normal conditions).
- Number of conductors (two, three, four, etc.).
- Core cross-section (same, different).
- Core structure (single-wire or multi-wire).
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 electric wires in the junction box.
Existing methods
The most popular and effective are considered the following options connections:
- 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!
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.
Most often, such caps are used to connect cores in distribution boxes.
Advantages of using these products:
- low cost of PPE;
- caps are made from non-flammable material, so twisting will not occur at the location;
- quick installation;
- caps have a wide range color shades. For example, if the wires do not have a wire, you can use PPE to mark it (using a white, blue and green cap).
Flaws:
- relatively poor quality isolation and fixation;
- It is impossible to combine aluminum with copper.
Crimping with special sleeves
Stranding and insulation
The old “grandfather’s” method consists of twisting the cores together. The essence of the work is that the conductors are stripped and carefully twisted with pliers, after which the twisted area is insulated.
Advantages:
- simplicity electro installation work;
- no material costs.
Flaws:
- poor quality of core fastening;
- The connection of aluminum and copper products is unacceptable.
WITH using existing methods We have figured out the connections of the wires in the box, now we will consider the remaining, important issues of this topic.
What to do if there are several wires?
There are usually no problems when connecting two contacts. But what to do if you need to combine three, four or more at the same time?
- using wago terminal blocks;
- crimping with sleeves;
- soldering;
- twisting using sizes;
- twisting and wrapping with electrical tape.
We discussed in detail the order of connecting the wires for each method above. We strongly recommend that you use the first option, because... it is one of the most modern and effective. At the same time, the cost of the vag is not too high, and the wiring lasts more than 30 years.
What to do if the wires are of different sections?
To connect cores of different cross-sections in the distribution box, it is recommended to use the same VAG terminal blocks, or more cheap option– regular terminal blocks. IN in this case you need to carefully tighten the wires with a screw or secure them with a flag, and that’s it, the work is finished.
We draw your attention to the fact that if the wires are made of different materials, then it is necessary to use special blocks with paste inside, which will prevent oxidation of the wires. Such pads include products from Wago.
Also veins different sections can be secured by soldering.
Combining stranded and single-core wires
Connecting single-core and stranded wires separately has no special features, so you can use any of the methods listed above.
In order to carry out fastening, you must choose one of two options: vago terminals or soldering. It all depends on your preference; we have provided the advantages and disadvantages of each method.
How to carry out work in water and land
During electrical installation work, a situation often occurs when it is necessary to fasten electrical wiring under water or in the ground. Now we will briefly look at the features of each case!
In water (for example, when installing submersible pump), it is recommended to use next technology. To begin with, the ends are soldered, after which the soldering area is carefully insulated with hot-melt adhesive, over which it is put on. If everything is done efficiently and conscientiously, the joint will be airtight and safe. Otherwise, the electrical network may fail.
To connect an electrical wire in the ground (for example, after it has been mechanically damaged), it is recommended to use the method provided above (hot glue and heat shrink), but it is better to protect yourself and use the following technique. Clamp the ends of the cable using a terminal block, install a sealed junction box, and then carefully fill the box with a special silicone sealant. Please note that the underground route must additionally be placed in a pipe or box to ensure reliable operation!
In stranded wires, the cross-section is formed by several, sometimes intertwined, cores. Knowing how to connect stranded wires to each other, you can easily do this work yourself and get a strong contact that is absolutely safe during operation.
Where are stranded wires used?
Any stranded conductor contains at its base a large number of thin wires. The use of a multi-core cable is important in areas that require a large number of bends or, if necessary, to pull the conductor through holes that are too narrow and long enough.
The scope of application of stranded conductors is presented:
- extended tees;
- mobile lighting devices;
- automotive wiring;
- connecting lighting fixtures to the electrical network;
- connecting switches or other types of levers to influence the electrical network.
Flexible stranded conductors can be twisted repeatedly and easily, which does not negatively affect the functionality of the system. Among other things, this particular type of electrical wiring is distinguished by plasticity, and greater flexibility and elasticity is imparted to the wire by weaving a special thread, which in strength and composition is a bit like nylon.
Methods for connecting stranded wires to each other
The methods used today for electrical connections of stranded conductors are distinguished by the ability to obtain not only strong, reliable and durable, but also completely safe contact of the conductors.
Stranding of stranded conductors
This option is the easiest to implement and intuitive, not requiring the use of special equipment or professional tools.
Twisting is the easiest way to connect stranded wires
The second method consists of the following steps:
Twisting wires using the third method:
There is also a fourth method, which is as follows:
Soldering method
Soldering the conductors using a household soldering iron ensures high-strength contact and good electrical conductivity. Tinning of stranded conductors is carried out using rosin (flux) and standard solder using standard technology.
Terminal type connections
The use of terminals of different types is the most affordable way to connect multi-core wires in everyday life. In most cases, the terminal blocks used are divided into a couple of main types.
The principle of operation of clamping terminals involves fixing the wire using a built-in spring mechanism.
Terminals are often used to connect wires
The screw-type terminal block involves reliable fixation of all connected stranded wires using a screw. To increase the area of wire contact with a conductive surface, an additional bend of the core is required.
The wires in the terminal block are secured by tightening the screws
Stage-by-stage execution of work:
Crimping method
The crimping method involves connecting wires or cables using a copper or aluminum sleeve using special crimping pliers of a hydraulic or manual type.
In this case, the connection is made using a special sleeve
The pressing technology involves stripping the insulation according to the length of the sleeve, and conductors that are too thin should be connected by twisting. Then all the cables are folded together and placed inside the sleeve, after which double crimping is performed along the entire length. The method allows you to make a reliable and safe connection of stranded wires made of different types materials.
Bolted connection
The simplest, but not reliable enough way to connect stranded wires is twisting followed by bolting. This detachable connection option is most often used in open wiring conditions.
Bolted connection is the simplest, but not very reliable
To increase the level of reliability of the connection of stranded wires, it is recommended to strip the ends of insulation, then tin the cleaned areas and fasten them with a bolt.
Application of connecting insulating clamps
PPE elements are used when it is necessary to connect stranded wires with a small cross-section (within 25 mm2). Design feature This type of clamp is made of a plastic body with a built-in cone-shaped spring.
This method is suitable for connecting wires with a small cross-section
Stranded wires are first connected into one bundle using twisting, onto which the clamping part is then screwed. Among other things, the wire connection does not require additional insulation.
Welding method
A permanent connection is the most reliable method when working with multi-core wires. When welding is performed correctly, general indicators mechanical strength and contact resistance in terms of reliability do not differ from similar parameters of a solid conductor.
Welding connection of wires is considered the most reliable
Welding can be performed on alternating and DC. On preparatory stage the wires are stripped of insulation, after which they are twisted and straightened by trimming the ends. To ensure that the conductors do not overheat during the welding process, it is necessary to ensure high-quality heat removal.
Security measures
In order to ensure safe operation of connected stranded wires, it is important to insulate all parts of the electrical wiring. Proper insulation helps prevent dangerous contact of conductive parts with each other or with the human body. When choosing an insulating material, it is necessary to take into account the operating conditions of the electrical circuit, but in most cases, insulating tape, as well as a special vinyl or heat-shrinkable tube, are used for this purpose.
If the connection area is exposed to the negative effects of high temperatures, it is recommended to use varnished cloth or fabric insulating tape as an insulating material. Correct execution of all stages is of no small importance. electrical installation. Only with reliable connection and proper connection of all elements of the electrical network is it possible to minimize the risk of areas with poor contact, and also prevent local overheating and electrical wiring breaks.
Multicore cables are a popular and widespread option, widely used for arranging electrical wiring for various purposes. The general rules for the separate connection of stranded and single-core conductors do not have any differences or features, therefore it is allowed to use twisting, screw clamps, PPE elements, welding and soldering for this purpose.
All electrical engineering, since the time of Faraday, uses wires. And for as many years as wires have been used, electricians have been faced with the problem of connecting them. This article explains what methods there are for connecting conductors, and the advantages and disadvantages of these methods.
Twist connection
The easiest way to connect wires is twisting. Previously, this was the most common method, especially when wiring in a residential building. Now, according to the PUE, connecting wires in this way is prohibited. The twist must be soldered, welded or crimped. However, these methods of connecting wires begin with twisting.
In order to perform high-quality twisting, the connected wires must be cleared of insulation to the required length. It ranges from 5 mm when connecting wires for headphones to 50 mm if it is necessary to connect wires with a cross-section of 2.5 mm². Thicker wires are usually not twisted together due to their high rigidity.
Wires are stripped sharp knife, insulation stripping pliers (ISR) or, after heating with a soldering iron or lighter, the insulation is easily removed with pliers or side cutters. For better contact bare areas are cleaned sandpaper. If the twist is supposed to be soldered, then it is better to tin the wires. Wires are tinned only with rosin and similar fluxes. This cannot be done with acid - it corrodes the wire and it begins to break at the soldering site. Even washing the soldering area in a soda solution doesn’t help. Acid vapors penetrate under the insulation and destroy the metal.
The stripped ends are folded parallel into one bundle. The ends are aligned together, the isolated part is held firmly with your hand, and the entire bundle is twisted with pliers. After this, the twist is soldered or welded.
If there is a need to connect the wires to increase the total length, then they are folded opposite each other. The cleaned areas are placed crosswise on top of each other, twisted together by hand and tightened tightly with two pliers.
You can only twist wire made of the same metal (copper with copper, and aluminum with aluminum) and of the same cross-section. Twisting wires of different sections will turn out uneven and will not provide good contact and mechanical strength. Even if it is soldered or crimped, these types of wire connections will not ensure good contact.
How to connect electrical wires by soldering
Compound electrical wires soldering is very reliable. You can solder untwisted wires, but such soldering will be fragile due to the fact that the solder is a very soft metal. In addition, it is very difficult to lay two conductors parallel to each other, especially when suspended. And if you solder on some kind of base, the rosin will stick the soldering area to it.
A layer of rosin is applied to the pre-tinned and twisted conductors with a soldering iron. If another flux is used, it is applied in the appropriate manner. The power of the soldering iron is selected based on the cross-section of the wire - from 15 W when soldering headphones to 100 W when soldering twisted wires with a cross-section of 2.5 mm². After applying the flux, tin is applied to the twist with a soldering iron and heated until the solder completely melts and flows into the twist.
After the soldering has cooled, it is insulated with electrical tape or a piece of heat-shrinkable tubing is put on it and heated with a hairdryer, lighter or soldering iron. When using a lighter or soldering iron, be careful not to overheat the heat shrink.
This method reliably connects wires, but is only suitable for thin wires, no more than 0.5 mm², or flexible ones up to 2.5 mm².
How to connect headphone wires
Sometimes the cable near the plug breaks off in working headphones, but there is a plug from faulty headphones. There are also other situations in which it is necessary to connect the wires in the headphones.
To do this you need:
- cut off a broken plug or an unevenly torn cable;
- strip the external insulation by 15–20 mm;
- determine which of the internal wires is common and check the integrity of all conductors;
- trim internal wiring according to the principle: do not touch one, common by 5 mm and the second by 10 mm. This is done to reduce the thickness of the connection. There can be two common conductors - each earphone has its own. In this case they are twisted together. Sometimes a screen is used as a common conductor;
- strip the ends of the wires. If varnish is used as insulation, it will burn off during the tinning process;
- tin the ends to a length of 5 mm;
- put a piece of heat-shrink tubing on the wire 30 mm longer than the expected length of the connection;
- put pieces of thinner heat-shrinkable tube 10 mm long on the long ends, do not put on the middle (general) ends;
- twist the wires (long with short, and middle with middle);
- solder the twists;
- bend the soldered twists outward to the unprotected edges, slide pieces of thin heat-shrinkable tubing onto them and heat it with a hairdryer or lighter;
- Slide a larger diameter heat-shrinkable tube onto the joint and warm it up.
If everything was done carefully and the color of the tube was matched to the color of the cable, then the connection will be invisible and the headphones will work no worse than new ones.
How to brew twist
For good contact, the twist can be welded with a graphite electrode or gas burner. Torch welding has not become widespread due to the complexity and the need to use gas and oxygen cylinders, so this article only talks about electric welding.
Electric welding is performed using a graphite or carbon electrode. Graphite electrode is preferable. It is cheaper and provides best quality welding Instead of a purchased electrode, you can use a rod from a battery or a brush from an electric motor. It is better not to use copper electrodes. They often get stuck.
For welding, you first need to make a twist 100 mm long, so that the finished one turns out to be about 50. The protruding wires need to be trimmed. For welding, it is best to use an inverter welding machine with adjustable current. If this is not the case, then you can take a regular transformer with a power of at least 600 W and a voltage of 12–24 V.
Near the insulation, “ground” or “minus” is connected using a thick copper clamp. If you simply wrap a wire around a twist, the twist will overheat and melt the insulation.
Before starting welding, it is necessary to select the current. The required current varies depending on the number and thickness of the wire that makes up the twist. The welding duration should be no more than 2 seconds. If necessary, welding can be repeated. If everything was done correctly, then a neat ball will appear at the end of the twist, soldered to all the wires.
How to connect wires by crimping
Another way to connect wires is crimping. This is a method in which a copper or aluminum sleeve is placed on the wires or cables to be connected, and then crimped with a special crimper. For thin sleeves, a manual crimper is used, and for thick ones, a hydraulic one is used. This method can even connect copper and aluminum wires, which is unacceptable with a bolted connection.
To connect using this method, the cable is stripped to a length greater than the length of the sleeve, so that after putting on the sleeve, the wire sticks out 10–15 mm. If thin conductors are connected by crimping, then twisting can be done first. If the cable has a large cross-section, then, on the contrary, in the stripped areas it is necessary to align the wire, fold all the cables together and give them round shape. Depending on local conditions, the cables can be folded with the ends in one direction or in the opposite direction. This does not affect the reliability of the connection.
A sleeve is tightly placed on the prepared cables or, when laid in opposite directions, the wires are inserted into the sleeve from both sides. If there remains in the sleeve free place, then it is filled with pieces of copper or aluminum wire. And if the cables do not fit in the sleeve, then a few wires (5–7%) can be cut off with side cutters. In the absence of a sleeve the right size You can take a cable lug by sawing off the flat part of it.
The sleeve is pressed 2–3 times along its length. The crimping points should not be located at the edges of the sleeve. It is necessary to retreat 7–10 mm from them so as not to crush the wire during crimping.
The advantage of this method is that it allows you to connect wires of different sections and from different materials, which is difficult with other connection methods.
A fairly common connection method is a bolted connection. For this type you need a bolt, at least two washers and a nut. The diameter of the bolt depends on the thickness of the wire. It should be such that a ring can be made from the wire. If wires of different sections are connected, then the bolt is selected according to the largest one.
To make a bolted connection, the end is cleared of insulation. The length of the stripped part should be such as to make a ring that fits onto the bolt using round pliers. If the wire is stranded (flexible), then the length should allow, after making the ring, to wrap the free end around the wire near the insulation.
In this way, you can connect only two identical wires. If there are more of them, or they are different in cross-section, rigidity and materials (copper and aluminum), then it is necessary to install conductive, usually steel washers. If you take a bolt of sufficient length, you can connect any number of wires.
Terminal block connection
A development of the bolted connection is the terminal connection. Terminal blocks come in two types - with a rectangular pressure washer and with a round one. When using a terminal block with a pressure washer, the insulation is removed to a length equal to half the width of the terminal block. The bolt is released, the wire is slipped under the washer and the bolt is clamped again. On one side, you can connect only two wires, preferably of the same cross-section and only flexible or only single-core.
Connecting to a terminal block with a round washer is no different from using a bolted connection.
The connection of the wires is reliable, but cumbersome. When connecting wires with a cross-section of more than 16 mm², the connection is unreliable or the use of lugs is necessary.
Self-clamping terminal blocks WAGO
In addition to terminal blocks with bolts, there are also terminal blocks with clamps. They are more expensive than usual, but they allow the connection to be made much faster, especially in connection with the new requirements of the PUE and the ban on twisting.
Most famous manufacturer Such terminal blocks are made by WAGO. Each terminal is a separate device with several holes for connecting wires, each of which is inserted into a separate wire. Depending on the version, it connects from 2 to 8 conductors. Some types are filled inside with conductive paste for better contact.
They are available for both detachable and permanent connections.
The stripped wire is simply inserted into the terminals for a permanent connection and spring tendrils fix the wire inside. Only hard (single-core) wire can be used.
In terminals for detachable connections, the wire is clamped using a folding lever and spring clamp, allowing you to easily connect and disconnect wires.
Since the wires do not touch each other, the terminals allow you to connect wires of different sections, single-core to stranded, copper to aluminum.
This method of connecting conductors has proven to work best at low currents and is most widespread in lighting networks. These terminals are small in size and easily fit into adapter boxes.
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. Connect if necessary copper cable with aluminum, special tips 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.
Soldering tips
Another way to use the tip is to solder it. To do this you need:
- stripped copper cable;
- tip designed for soldering. It is distinguished by a hole near the flat part and a thinner wall;
- bath of molten tin;
- a jar of phosphoric acid;
- a jar of soda solution.
Carefully! Wear protective glasses and gloves!
In order to solder the tip, the cable is cleared of insulation along the length of the tubular part and inserted into the tip. Then the tip is successively immersed in orthophosphoric acid, in molten tin for a time sufficient for the acid to boil away and the solder to flow into the tip. This is checked by periodically briefly removing it from the solder. After impregnating the tip and cable with solder, the tip is dipped in a soda solution. This is done to neutralize acid residues. The cooled tip can be washed clean water and ready for further work. Such a tip can be connected to aluminum busbars and lugs without the use of adapter washers.
Connectors for cables and wires
Cables can also be connected using special connectors. These are sections of pipe in which threads are cut and bolts are screwed in. There are detachable connectors, in which the bolts are unscrewed, and permanent ones. In permanent connectors, the bolt heads break off after clamping. There are also connectors designed to connect wires and cables of different sections. The cables are inserted end-to-end into the connectors, facing each other.
Connectors used on air lines power transmission, consist of two halves connected by bolts. The wires are laid in special grooves towards each other, parallel to each other, after which both halves are clamped with bolts.
Connecting wires and cables using couplings
If the cable to be connected is in the ground, water or rain, then conventional methods of isolating the connection are not suitable. Even if you apply a layer to the cable silicone sealant and compress it with heat shrink tube, this will not guarantee tightness. Therefore, it is necessary to use special couplings.
Couplings are available in plastic and metal casings, poured and heat-shrinkable, high-voltage and low-voltage, regular and small-sized. The choice of coupling depends on the specific operating conditions and the presence or absence of mechanical loads.
Connecting wires and cables is one of the most important points during electrical installation. Therefore, all methods of connecting electrical wires must ensure good contact. Poor contact or poor insulation may result in short circuit and fire.
Video on the topic
Power terminal
Soldering wires in headphones
Knowledge of modern technologies and methods of working with electrical fittings, is it really necessary? Yes, you need to know how to connect electrical wires correctly.
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. Great choice to implement a modern method of connecting wires.
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 stranded wire conductors themselves. 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 are an excellent product for such work. 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 the usual version, this product is used for one-time use; during repair work in the future it cannot be restored. 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. Simple mechanism lever type 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: A unique opportunity to combine 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 you're done. 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 on different sides of the tube or on one side. The sleeves are quite inexpensive. Good way how to reliably connect the wires to each other.
There are also disadvantages. Disposable use of sleeves, they are not dismountable. 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 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 regulatory framework fastening wires with twists in a junction box, not recommended for use 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 disconnect 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
It would seem that what could be simpler than connecting wires? After all, there are several ways to connect wires. This includes twisting wires, soldering wires, welding wires, crimping and connecting wires using a terminal block. Even a schoolboy knows the easiest way to twist conductors. You need to put the ends of the metal wires, called strands, together and twist them into one “pigtail”, and then wrap them with electrical tape. There is no need for a soldering iron, terminal block, connecting caps and other “unnecessaries”.
Any “own electrician” has mastered this operation. And, when the need arises, he applies this method in his daily practice. For example, it splices the power cord wires of a household appliance, tablet or computer adapter after a break.
Russian “technicians” use this technology for fastening wires everywhere. It’s just that the rules for constructing electrical installations of PES do not provide for “twisting”, all kinds of “bends” and “rivets”. There are no such methods of electrical installation in other regulatory documents. Why?
We often don’t think about the consequences of such a “simplification”. Meanwhile, an unreliable contact will fail at the most inopportune moment; the power supply to consumers/power receivers can always be cut off. Voltage surges cause breakdown of elements of complex power cascades. household appliances SBT. They don’t even save you from breakdown special devices protection used in the most sophisticated models of foreign manufacturers.
Induction of short electromagnetic pulses with a voltage of several thousand volts onto electronic stuffing causes “harmless” sparking at the joints. At the same time, the standard protection equipment that apartments are now equipped with (RCD, circuit breakers, fuses) such short low-current pulses are not “seen”, so they simply do not trigger, and we do not customarily install special devices for this. Sources uninterruptible power supply Computers also did not become a panacea for transient impulses. The occurrence of “poke” causes malfunctions in the operation of electronic equipment and computer equipment, leading to failure of electrical components and expensive functional modules.
Overheating at the site of a poor connection leads to even more catastrophic consequences; when current passes, the weakened connecting node becomes red-hot. This often causes fires and fires, causing enormous damage to the owners of the premises. Statistics show that 90% of all electrical wiring faults occur due to twists and poor contact connections of conductors. In turn, the very malfunction of electrical wiring and equipment, according to the Ministry of Emergency Situations, is the cause of one third of the fires that occur in Russia.
However, it so happened historically that several decades ago, in conditions of a shortage of electrical accessories/copper conductors, twisting aluminum wires was considered the main method used in electrical installation work. Twisting as a connection can be used in electrical engineering when carrying out repair and restoration work.
How to connect wires correctly
How to connect the wires: we start by removing the insulation. Correct connection of conductors must satisfy three basic requirements:
- Ensure reliable contact with a minimum transition resistance between each other, close to the resistance of a single piece of wire.
- Maintain tensile strength, fracture resistance and vibration resistance.
- Connect only homogeneous metals (copper to copper, aluminum to aluminum).
There are several connection methods that satisfy these requirements. Depending on the requirements for electrical wiring and the possibilities of practical application, the following types of wire connections are used:
All these methods require preliminary preparation wire or cable - stripping the insulation to expose the connected cores. Traditionally, rubber, polystyrene, and fluoroplastic are used as insulating shell materials. Additionally, polyethylene, silk and varnish serve as insulation inside. Depending on the structure of the conductive part, the wire can be single-core or multi-core.
By single-core is meant a wire whose cross-section is formed by an insulating sheath with a metal core or wiring inside.
In a stranded wire, the metal core is formed by several thin wires. They are usually intertwined and represent a lay, surrounded on the outside by an insulator. Often individual veins become covered polyurethane varnish, and nylon threads are added to the structure between them to increase the strength of the wire. These materials, like the fabric braid on the outside, complicate the process of removing the insulation.
Depending on the type of connection, 0.2–5.0 cm of insulation is removed from each end of the wire. Several types of tools are used for this.
Using a 5-point system, you can evaluate the quality of insulation removal and the degree of protection against cutting - damage to cores by each device:
Damage to insulation/core
Monter (kitchen) knife – 3/3
Side cutters (nippers) - 4/3
Stripper - 5/4
Soldering iron or electric loop burner - 4/4
In low-current television/computer networks, coaxial cables are used. During the cutting process, it is important to carefully cut and remove the insulating jacket without damaging the shielding braid. To access the central vein, it is fluffed up and removed, exposing the trunk. After which the polyethylene insulation is cut with a knife or a special device, the trim is removed from the core.
The bifilar in the screen consists of a pair of wires in the screen, which, in order to access the conductors, is also pre-fluffed into wires, allowing access to each core.
Important! To remove the insulating material of an enameled wire with a cross-section of less than 0.2 mm², a soldering iron should be used. The enamel is carefully removed using sandpaper and moving the paper along the wires.
How to twist wires correctly
Most often, twisting is used in the repair of electrical wiring, cords and adapters (including low-current) household appliances and equipment. If we are talking about the home electrical network, then the standards provide for the use in homes of wires with a current-carrying core cross-section of 1.5–2.0 mm made of copper and 2.5–4.0 mm made of aluminum. Typically, wires of the VVG and PV brands in a polyvinyl chloride sheath are used for wiring. Power cords of the ShVL and ShTB brands with rubber or PVC insulation have a cross-section of 0.5 - 0.75 mm.
You can splice the wires together step by step as follows:
- Degrease the bare ends of the wires by wiping with acetone/alcohol.
- We remove the varnish layer or oxide film by sanding the conductors with sandpaper.
- Apply the ends so that they intersect. We wind clockwise at least 5 turns of one core onto another. To make the twist tight, use pliers.
- We insulate the open current-carrying parts of the wires using electrical tape, or screw on an insulating cap. They should extend beyond the insulation for 1.5–2.0 s to cover the exposed areas of the conductors.
To splice a stranded stripped wire with a single-core wire, another winding technique is used:
- A single wire is wrapped with a stranded wire, leaving the end free without winding.
- The end of the single-core wire is bent 180° so that it presses the twist, then pressed with pliers.
- The connection point must be firmly fixed with electrical tape. For better efficiency an insulating heat pipe should be used. To do this, a piece of cambric of the required length is pulled over the connection. To make it grip the wiring more tightly, the tube should be heated, for example, with a hair dryer or lighter.
With a bandage connection, the free ends are placed next to each other and wrapped on top with an existing piece of wire (bandage) made of a homogeneous material.
Coupling with a groove provides that before mutual twisting, small hooks are configured from the ends of the wire, they are interconnected, then the edges are wrapped.
There are more complex varieties of parallel/serial connections. Connecting wires using the twisting method is used by professional electrical repairmen when carrying out restoration work.
Important! Copper and aluminum have different ohmic resistances; when they interact, they actively oxidize; due to different hardnesses, the connection turns out to be fragile, so the connection of these metals is undesirable. In case of emergency, the ends to be connected should be prepared - tinned with tin-lead solder (PLS) using a soldering iron.
Why is it better to crimp (crimp) wires?
Wire crimping is one of the most reliable and quality ways mechanical connections currently in use. With this technology, loops of wires and cables are crimped into a connecting sleeve using press pliers, ensuring tight contact along the entire length.
The sleeve is a hollow tube and can be made independently. For liner sizes up to 120 mm², mechanical pliers are used. For large sections, products with a hydraulic punch are used.
When compressed, the sleeve usually takes the shape of a hexagon; sometimes local indentation is made in certain parts of the tube. In crimping, sleeves made of electrical copper GM and aluminum tubes GA are used. This method allows crimping of conductors from different metals. This is largely facilitated by the treatment of the constituent components with quartz-vaseline lubricant, which prevents subsequent oxidation. For joint use, there are combined aluminum-copper sleeves or tinned copper sleeves GAM and GML. Wire connections using the crimp method are used for conductor bundles with a total cross-sectional diameter between 10 mm² and 3 cm².
Soldering as a reliable alternative to twisting
The closest alternative to twisting, which is prohibited for electrical installation, is to connect wires using the soldering method. It requires special tools and Supplies, but provides absolute electrical contact.
Advice! Overlapping wire soldering is considered the most unreliable in technology. During operation, the solder crumbles and the connection opens. Therefore, before soldering, apply a bandage, wrap a piece of wire of a smaller diameter around the parts being connected, or twist the conductors together.
You will need an electric soldering iron with a power of 60–100 W, a stand and tweezers (pliers). The soldering iron tip should be cleaned of scale, sharpened, having first selected the most suitable shape of the tip in the form of a spatula, and the body of the device should be connected to the ground wire. Among the “consumables” you will need POS-40, POS-60 solder from tin and lead, rosin as a flux. You can use solder wire with rosin placed inside the structure.
If you need to solder steel, brass or aluminum, you will need a special soldering acid.
Important! Do not overheat the junction points. To prevent the insulation from melting when soldering, be sure to use a heat sink. To do this, hold the bare wire between the heating point and the insulation with tweezers or needle-nose pliers.
- The wires stripped of insulation should be tinned, for which the tips heated with a soldering iron are placed in a piece of rosin; they should be covered with a brown-transparent layer of flux.
- We place the tip of the soldering iron tip into the solder, grab a drop of molten solder and evenly process the wires one by one, turning and moving along the tip blade.
- Attach or twist the wires together, securing them motionless. Warm up with the tip for 2–5 s. Treat the areas to be soldered with a layer of solder, allowing the drop to spread over the surfaces. Turn over the wires to be connected and repeat the operation on the reverse side.
- After cooling, the soldering joints are insulated in the same way as twisting. In some compounds, they are pre-treated with a brush dipped in alcohol and coated with varnish.
Advice! During and after soldering for 5–8 s. The wires cannot be pulled or moved, they must be in a stationary position. A signal that the structure has hardened is when the solder surface acquires a matte tint (it shines in the molten state).
But welding is still preferable
In terms of connection strength and contact quality, welding surpasses all other technologies. Recently, portable welding inverters, which can be transferred to the most inaccessible places. Such devices are easily held on the welder's shoulder using a belt. This allows you to work in hard to reach places, for example, welding from a stepladder in a distribution box. To weld metal cores, carbon pencils or copper-plated electrodes are inserted into the holder of the welding machine.
The main disadvantage of welding technology - overheating of the parts being welded and melting of the insulation - is eliminated using:
- Correct adjustment welding current 70–120 A without overheating (depending on the number of welded wires with a cross-section from 1.5 to 2.0 mm).
- The duration of the welding process is no more than 1–2 seconds.
- Tightly pre-twist the wires and install a copper heat sink clamp.
When connecting wires by welding, the twisted wires should be bent and the cut side must be turned upward. An electrode is brought to the end of the wires connected to ground and the electric arc is ignited. The molten copper flows down in a ball and covers the twisted wire with a sheath. During the cooling process, an insulating belt made from a piece of cambric or other insulating material is put on the warm structure. Lacquered fabric is also suitable as an insulating material.
Terminal blocks are the most ergonomic electrical installation products
The PUE rules, clause 2.1.21 provide for the type of connections using clamps (screws, bolts). There is a connection directly using hanging fasteners, when a screw and washer are threaded through the loops of each wire and secured with a nut on the reverse side.
This installation is wrapped with several turns of electrical tape and is considered quite practical and reliable.
Electrical installation products called screw terminal blocks are more ergonomic. They represent a contact group housed in a housing made of insulating material (plastic, porcelain). The most common way to connect wires using terminal blocks is in junction boxes and electrical panels. To connect the wire, you need to insert it into the socket and tighten the screw, clamping bar will securely fasten the core to the seat. Another connecting wire is connected to the mating socket, short-circuited with the first one.
In self-clamping terminal blocks of the WAGO type, the wire is snapped into the socket; for better contact, a special paste or gel is used.
Branch clamps represent a permanent version of a screw terminal block with several short-circuited taps; they are used mainly on the street and in places with unfavorable conditions environment.
The connecting clamps are an insulating cap with a thread inside; it is screwed onto the twist, simultaneously compressing and protecting from mechanical stress.
