Electricity is an area where everything needs to be done correctly and thoroughly. In this regard, many people prefer to figure things out on their own rather than trust strangers. One of key points— connection of wires in the junction box. Firstly, the correct operation of the system, and secondly, safety - electrical and fire safety - depends on the quality of work.
What is a junction box
From the electrical panel, the wires disperse throughout the rooms in the house or apartment. Each room, as a rule, has more than one connection point: there are several sockets and a switch. To standardize the methods of connecting wires and collect them in one place, distribution boxes are used (they are also sometimes called branch boxes or junction boxes). They contain cables from all connected devices, the connection of which occurs inside the hollow housing.
So that in the process next repair do not look for wiring, it is laid according to certain rules that are prescribed in the PUE - Rules for the Construction of Electrical Installations.
One recommendation is to carry out all connections and branch wires in the junction box. Therefore, the wires are run along the top of the wall, at a distance of 15 cm from the ceiling level. Having reached the branch point, the cable is lowered vertically down. A distribution box is installed at the branch point. It is where all the wires are connected according to the required circuit.
According to the type of installation, junction boxes are internal (for hidden installation) and external. Under the internal ones, a hole is made in the wall into which the box is built. With this installation, the cover is flush with the finishing material. Sometimes it is closed during the renovation process. finishing materials. However, such installation is not always possible: the thickness of the walls or finishing does not allow it. Then a box for external mounting is used, which is attached directly to the wall surface.
The shape of the junction box can be round or rectangular. There are usually four conclusions, but there may be more. The terminals have threads or fittings to which it is convenient to attach a corrugated hose. After all, it is more convenient to lay wires in a corrugated hose or plastic pipe. In this case, replacing the damaged cable will be very simple. First, disconnect it in the distribution box, then from the consumer (socket or switch), pull it and pull it out. Tighten a new one in its place. If you lay it the old fashioned way - in a groove, which is then covered with plaster - you will have to drill into the wall to replace the cable. So this is the recommendation of the PUE, which is definitely worth listening to.
What do distribution boxes generally provide:
- Increased maintainability of the power supply system. Since all connections are accessible, it is easy to determine the area of damage. If the conductors are laid in cable channels (corrugated hoses or pipes), replacing the damaged section will be easy.
- Most electrical problems arise in the connections, and with this installation option they can be inspected periodically.
- Installing junction boxes increases the level fire safety: everything is potential dangerous places are located in certain places.
- Requires less money and labor than laying cables to each outlet.
Wire connection methods
Conductors can be connected in the box different ways. Some of them are more difficult to implement, others are easier, but if implemented correctly, they all provide the required reliability.
Twist
The most popular method among folk craftsmen, but the most unreliable. It is not recommended by the PUE for use, as it does not provide proper contact, which can lead to overheating and a fire. This method can be used as a temporary method, for example, to check functionality assembled circuit, with mandatory subsequent replacement with a more reliable one.
Even if the connection is temporary, everything must be done according to the rules. The methods for twisting stranded and single-core conductors are similar, but have some differences.
When twisting stranded wires, the procedure is as follows:
- the insulation is stripped to 4 cm;
- the conductors unwind by 2 cm (item 1 in the photo);
- connect to the junction of untwisted conductors (pos. 2);
- the veins are twisted with your fingers (position 3);
- the twist is tightened with pliers or pliers (pos. 4 in the photo);
- insulated (insulating tape or heat-shrinkable tubing placed before the connection).
Connecting wires in a distribution box with one core using twisting is easier. The conductors, stripped of insulation, are crossed and twisted with fingers along their entire length. Then take a tool (pliers and pliers, for example). In one, the conductors are clamped near the insulation, in the second, the conductors are intensively twisted, increasing the number of turns. The connection point is isolated.
Twist with pliers or pliers
Twist with mounting caps
Twisting is even easier using special caps. With their use, the connection is more reliably insulated and the contact is better. The outer part of such a cap is cast from flame retardant plastic; a metal conical part with a thread is inserted inside. This insert provides a larger contact surface, improving electrical characteristics connections. This great way connect two (or more) wires without soldering.
Twisting wires using caps is even simpler: 2 cm of insulation is removed, the wires are slightly twisted. A cap is put on them and turned with force several times until the metal is inside the cap. That's it, the connection is ready.
Caps are selected depending on the cross-section and number of conductors that need to be connected. This method is more convenient: it takes up less space than conventional twisting, and everything fits more compactly.
Soldering
If you have a soldering iron in the house and you know how to handle it at least a little, it is better to use soldering. Before twisting, the wires are tinned: a layer of rosin or soldering flux is applied. The heated soldering iron is dipped in rosin and passed several times over the part that has been stripped of insulation. A characteristic reddish coating appears on it.
After this, the wires are twisted as described above (twisting), then they take the tin on a soldering iron, heat the twist until the molten tin begins to flow between the turns, enveloping the connection and ensuring good contact.
Installers do not like this method: it takes a lot of time, but if you are connecting the wires in the junction box for yourself, spare no time and effort, but you will sleep peacefully.
Welding wires
If available, you can use a welded connection. This is done on top of the twist. Set the welding current on the machine:
- for a cross section of 1.5 mm 2 about 30 A,
- for a cross section of 2.5 mm 2 - 50 A.
The electrode used is graphite (this is for welding copper). Using grounding pliers, we carefully cling to the upper part of the twist, bring the electrode to it from below, briefly touch it, achieving ignition of the arc, and remove it. Welding occurs in a fraction of a second. After cooling, the joint is insulated. Watch the video for the process of welding wires in a junction box.
Terminal blocks
Another connection of wires in the distribution box is using terminal blocks - terminal blocks, as they are also called. Eat different types pads: with clamps and screw ones, but, in general, the principle of their design is the same. There is a copper sleeve/plate and a wire fastening system. They are designed so that by inserting into Right place two/three/four conductors, you connect them securely. The installation is very simple.
Screw terminal blocks have a plastic housing in which the contact plate is fixed. They are of two types: with hidden contacts (new) and with open contacts (old style). In any of them, a conductor stripped of insulation (length up to 1 cm) is inserted into the socket and clamped with a screw and a screwdriver.
Their disadvantage is that it is not very convenient to connect a large number of wires in them. The contacts are arranged in pairs, and if you need to connect three or more wires, you have to squeeze two wires into one socket, which is difficult. But they can be used in branches with significant current consumption.
Another type of block is Vago terminal blocks. These are pads for quick installation. There are mainly two types used:
The peculiarity of these terminal blocks is that they can only be used at low currents: up to 24 A with a copper wire cross-section of 1.5 mm, and up to 32 A with a cross-section of 2.5 mm. When connecting loads with high current consumption, the wires in the junction box must be connected in a different way.
Crimping
This method is possible with special pliers and a metal sleeve. A sleeve is put on the twist, it is inserted into the pliers and clamped - crimped. This method is just suitable for lines with a large ampere load (such as welding or soldering). Watch the video for details. It even contains a model of a distribution box so it will be useful.
Basic wiring diagrams
Knowing how to connect the wires in the junction box is not everything. You need to figure out which wires to connect.
How to connect sockets
As a rule, the socket group runs on a separate line. In this case, everything is clear: you have three cables in the box, each with three (or two) conductors. The color may be the same as in the photo. In this case, usually brown is the phase wire, blue is neutral (neutral), and yellow-green is ground.
In another standard, the colors may be red, black and blue. In this case, the phase is red, blue is neutral, green is ground. In any case, the wires are collected by color: all of the same color in one group.
Then they are folded, stretched, and trimmed so that they are the same length. Do not cut short, leave a margin of at least 10 cm so that if necessary you can re-seal the connection. Then the conductors are connected using the chosen method.
If only two wires are used (in houses of old construction there is no grounding), everything is exactly the same, only there are two connections: phase and neutral. By the way, if the wires are the same color, first find the phase (with a probe or multimeter) and mark it, at least by wrapping a piece of electrical tape around the insulation.
Connecting a single-key switch
If there is a switch, the matter is more complicated. There are also three groups, but their connection is different. Eat
- input - from another junction box or from a panel;
- from the chandelier;
- from the switch.
How should the circuit work? Power - “phase” - goes to the switch key. From its output it is fed to the chandelier. In this case, the chandelier will light only when the switch contacts are closed (the “on” position). This type of connection is shown in the photo below.
If you look carefully, this is what happens: the phase with a light wire goes to the switch. It leaves from another contact, but this time blue (do not mix it up) and connects to the phase wire that goes to the chandelier. Neutral (blue) and ground (if network) are twisted directly.
Connecting a two-gang switch
Connecting wires in a junction box with a two-button switch is a little more complicated. The peculiarity of this circuit is that a three-core cable must be laid to the switch for two groups of lamps (in a circuit without grounding). One wire is connected to the common contact of the switch, the other two to the key outputs. In this case, it is necessary to remember what color the conductor is connected to the common contact.
In this case, the phase that has arrived is connected to the common contact of the switch. The blue wires (neutral) from the input and two lamps are simply twisted all three together. There are wires left - phase wires from the lamps and two wires from the switch. So we connect them in pairs: one wire from the switch to the phase of one lamp, the second output to the other lamp.
Once again about connecting the wires in the junction box when two-button switch in video format.
Wire connection methods
Contact connections of conductors are a very important element of the electrical circuit, therefore, when performing electrical installation work, you must always remember that the reliability of any electrical system is largely determined by the quality of workmanship electrical connections.
All contact connections have certain technical requirements. But first of all, these connections must be resistant to mechanical factors, reliable and safe.
With a small contact area, quite significant resistance to the passage of current can arise in the contact zone. The resistance at the point where current passes from one contact surface to another is called transition contact resistance, which is always greater than the resistance of a solid conductor of the same size and shape. During operation, the properties of a contact connection under the influence of various external and internal factors can deteriorate so much that an increase in its contact resistance can cause overheating of the wires and create an emergency situation. The transient contact resistance largely depends on the temperature, with an increase in temperature (as a result of the passage of current) the transition resistance of the contact increases. Contact heating is of particular importance due to its influence on the oxidation process of contact surfaces. In this case, the oxidation of the contact surface is more intense, the higher the contact temperature. The appearance of an oxide film, in turn, causes a very strong increase in contact resistance.
This is an element of an electrical circuit where the electrical and mechanical connection of two or more separate conductors is made. At the point where the conductors touch, an electrical contact is formed - a conductive connection through which current flows from one part to another.
Simple overlay or slight twisting of the contact surfaces of the connected conductors does not provide good contact, since due to micro-irregularities, actual contact does not occur over the entire surface of the conductors, but only at a few points, which leads to a significant increase in the transition resistance.
At the point of contact of two conductors, a transition resistance of the electrical contact always arises, the value of which depends on physical properties contacting materials, their condition, compression force at the point of contact, temperature and actual contact area.
From the point of view of the reliability of electrical contact aluminum wire cannot compete with copper. After a few seconds of exposure to air, the pre-cleaned aluminum surface is covered with a thin, hard and refractory oxide film with high electrical resistance, which leads to increased transient resistance and strong heating of the contact zone, resulting in an even greater increase in electrical resistance. Another feature of aluminum is its low yield strength. A tightly tightened connection of aluminum wires weakens over time, which leads to a decrease in the reliability of the contact. In addition, aluminum has poorer conductivity. That is why use in household electrical systems aluminum wires are not only inconvenient, but also dangerous.
Copper oxidizes in air at normal residential temperatures (about 20 °C). The resulting oxide film does not have great strength and breaks easily when compressed. Particularly intense oxidation of copper begins at temperatures above 70 °C. The oxide film on the copper surface itself has insignificant resistance and has little effect on the value of the contact resistance.
The condition of the contact surfaces has a decisive influence on the growth of the contact resistance. To obtain a stable and durable contact connection, high-quality cleaning and surface treatment of the connected conductors must be performed. The insulation from the conductors is removed to the required length with a specialized tool or knife. Then the exposed parts of the veins are cleaned with emery cloth and treated with acetone or white spirit. The length of the cutting depends on the characteristics of the specific method of connection, branching or termination.
The transient contact resistance decreases significantly with increasing compression force of the two conductors, since the actual contact area depends on it. Thus, to reduce the transition resistance in the connection of two conductors, it is necessary to ensure sufficient compression, but without destructive plastic deformations.
There are several ways to make an electrical connection. The highest quality of them will always be the one that provides, under specific conditions, the lowest value of transient contact resistance for the longest possible time.
According to the “Rules for Electrical Installations” (clause 2.1.21), connection, branching and terminating of wires and cables must be done by welding, soldering, crimping or clamping (screw, bolt, etc.) in accordance with current instructions. In such connections it is always possible to achieve a consistently low transient contact resistance. In this case, it is necessary to connect the wires in compliance with technology and using appropriate materials and tools.
This is an important and responsible operation. It can be performed different ways: using terminal blocks, soldering and welding, crimping, and often ordinary twisting. All of these methods have certain advantages and disadvantages. It is necessary to select a connection method before starting installation, as this also involves the selection of appropriate materials, tools and equipment.
At connecting wires the same color of neutral, phase and ground wires should be observed. Typically, the phase wire is brown or red, the neutral wire is blue, and the protective ground wire is yellow-green.
Very often, electricians have to connect a wire to an existing line. In other words, it is necessary to create a branch of wires. Such connections are made using special branch clamps, terminal blocks and piercing clamps.
In direct contact, copper and aluminum form a galvanic couple, and an electrochemical process occurs at the point of contact, as a result of which the aluminum is destroyed. Therefore, to connect copper and aluminum wires, you need to use special terminal or bolt connections.
Wires connected to various devices, often require special tips that help ensure reliable contact and reduce contact resistance. Such lugs can be attached to the wire by soldering or crimping.
There are the most various types. For example, for copper stranded conductors, lugs are produced from a solid-drawn copper pipe, flattened and drilled for a bolt on one side.
Welding. Connecting wires by welding.
It gives a monolithic and reliable contact, so it is widely used in electrical installation work.
Welding is performed at the ends of pre-stripped and twisted conductors with a carbon electrode using welding machines with a power of about 500 W (for twist cross-sections up to 25 mm2). The current on the welding machine is set from 60 to 120 A depending on the cross-section and number of wires being welded.
Due to the relatively low currents and low (compared to steel) melting point, the process occurs without a large dazzling arc, without deep heating and spattering of the metal, which makes it possible to use safety glasses instead of a mask. At the same time, other security measures may be simplified. After welding is completed and the wire has cooled, the bare end is insulated using electrical tape or heat-shrink tubing. After a little training, welding can be used to make connections quite quickly and efficiently. electrical wires and cables in the power supply system.
When welding, the electrode is brought close to the wire being welded until it touches, then withdrawn a short distance (OD-1 mm). The resulting welding arc melts the twisted wires until a characteristic ball is formed. Touching the electrode should be short-term to create the desired melting zone without damaging the wire insulation. It is impossible to make a longer arc length, since the welding site turns out to be porous due to oxidation in the air.
Currently welding work It is convenient to connect electrical wires using an inverter welding machine, since it has a small volume and weight, which allows the electrician to work on a stepladder, for example, under the ceiling, hanging a welding inverter apparatus on your shoulder. To weld electrical wires, a graphite electrode coated with copper is used.
In a welded joint, electric current flows through a monolithic metal of the same type. Of course, the resistance of such connections turns out to be record low. In addition, this connection has excellent mechanical strength.
Of all the known methods of connecting wires, none of them can be compared with welding in terms of durability and contact conductivity. Even soldering breaks down over time, since the connection contains a third, more fusible and loose metal (solder), and at the border of different materials there is always additional contact resistance and destructive chemical reactions are possible.
Soldering. Connecting wires by soldering.
Soldering is a method of joining metals using another, more fusible metal. Compared to welding, soldering is simpler and more affordable. It does not require expensive equipment, is less fire hazardous, and the skills needed to perform good quality soldering will require more modest skills than when making a welded joint. It should be noted that the metal surface in air is usually quickly covered with an oxide film, so it must be cleaned before soldering. But the cleaned surface can quickly oxidize again. To avoid this, apply to the treated areas chemical substances- fluxes that increase the fluidity of molten solder. This makes the soldering stronger.
Soldering is also the best way termination of copper stranded conductors into a ring - the soldered ring is evenly covered with solder. In this case, all wires must completely fit into the monolithic part of the ring, and its diameter must correspond to the diameter of the screw clamp.
The process of soldering wires and cable cores consists of covering the heated ends of the connected wires with molten tin-lead solder, which after hardening provides mechanical strength and high electrical conductivity of the permanent connection. The soldering must be smooth, without pores, dirt, sagging, sharp bulges of solder, or foreign inclusions.
To solder copper conductors of small cross-sections, use solder tubes filled with rosin, or a solution of rosin in alcohol, which is applied to the joint before soldering.
To create a high-quality soldered contact connection, the wire (cable) cores must be thoroughly tinned, and then twisted and crimped. From correct twist The quality of the soldered contact largely depends.
After soldering, the contact connection is protected by several layers of insulating tape or heat shrink tubing. Instead of insulating tape, the soldered contact connection can be protected with an insulating cap (PPE). Before this, it is advisable to coat the finished joint with a moisture-resistant varnish.
Heating of parts and solder is carried out with a special tool called a soldering iron. Required condition To create a reliable connection using the soldering method, the temperature of the surfaces being soldered is the same. The ratio of the temperature of the soldering iron tip and the melting temperature is of great importance for the quality of soldering. Naturally, this can only be achieved with the help of a properly selected tool.
Soldering irons vary in design and power. To perform household electrical work, a conventional electric rod soldering iron with a power of 20-40 W is quite sufficient. It is advisable that it be equipped with a temperature regulator (with a temperature sensor) or at least a power regulator.
Experienced electricians often use an original method for soldering. In the working rod of a powerful soldering iron (at least 100 W), a hole with a diameter of 6-7 mm and a depth of 25-30 mm is drilled and filled with solder. In a heated state, such a soldering iron is a small tin bath, which allows you to quickly and efficiently solder several multi-core connections. Before soldering, a small amount of rosin is thrown into the bath, which prevents the appearance of an oxide film on the surface of the conductor. The further soldering process involves lowering the twisted connection into such an improvised bath.
One common way to create a contact is to use screw terminal blocks. In them, reliable contact is ensured by tightening the screw or bolt. In this case, it is recommended to connect no more than two conductors to each screw or bolt. When using stranded wires in such connections, the ends of the wires require preliminary tinning or the use of special tips. The advantage of such connections is their reliability and disassembly.
According to their purpose, terminal blocks can be feed-through or connecting.
Designed for connecting wires to each other. They are usually used for switching wires in junction boxes and distribution boards.
Feed-through terminal blocks are used, as a rule, for connecting various devices (chandeliers, lamps, etc.) to the network, as well as for splicing wires.
When connecting wires with stranded conductors using screw terminal blocks, their ends require preliminary soldering or crimping with special lugs.
When working with aluminum wires, the use of screw terminal blocks is not recommended, since aluminum cores, when tightened with screws, are prone to plastic deformation, which leads to a decrease in the reliability of the connection.
Recently, a very popular device for connecting wires and cable cores has become self-clamping terminal blocks WAGO type. They are designed for connecting wires with a cross-section of up to 2.5 mm2 and are designed for an operating current of up to 24 A, which allows you to connect a load of up to 5 kW to the wires connected by them. In such terminal blocks you can connect up to eight wires, which significantly speeds up the installation of wiring in general. True, compared to twisting, they occupy in unsoldered boxes more space, which is not always convenient.
The screwless terminal block is fundamentally different in that its installation does not require any tools or skills. The wire, stripped to a certain length, is inserted into place with little effort and securely pressed by a spring. The design of a screwless terminal connection was developed by the German company WAGO back in 1951. There are other manufacturers of this type of electrical products.
In spring-loaded self-clamping terminal blocks, as a rule, the effective contacting surface area is too small. At high currents, this leads to heating and release of the springs, resulting in a loss of their elasticity. Therefore, such devices should be used only on connections that are not subject to heavy loads.
WAGO produces terminal blocks both for installation on a DIN rail and for fastening with screws to a flat surface, but when installed as part of home electrical wiring, construction terminal blocks are used. These terminal blocks are available in three types: for distribution boxes, for lamp fittings and universal.
WAGO terminal blocks for distribution boxes they allow connecting from one to eight conductors with a cross-section of 1.0-2.5 mm2 or three conductors with a cross-section of 2.5-4.0 mm2. And terminal blocks for lamps connect 2-3 conductors with a cross section of 0.5-2.5 mm2.
The technology for connecting wires using self-clamping terminal blocks is very simple and does not require special tools or special skills.
There are also terminal blocks in which the conductor is fixed using a lever. Such devices allow you to achieve good pressure, reliable contact and are easy to disassemble.
One of the connecting products popular among electrical installers is. This clamp is a plastic case, inside of which there is an anodized conical spring. To connect the wires, they are stripped to a length of about 10-15 mm and folded into a common bundle. Then the PPE is screwed onto it, rotating clockwise until it stops. In this case, the spring compresses the wires, creating the necessary contact. Of course, all this happens only when the PPE cap is selected correctly according to its rating. Using such a clamp, it is possible to connect several single wires with a total area of 2.5-20 mm2. Naturally, the caps in these cases are of different sizes.
Depending on the size, PPE has specific numbers and is selected according to the total cross-sectional area of the strands being twisted, which is always indicated on the packaging. When choosing PPE caps, you should focus not only on their number, but also on the total cross-section of wires for which they are designed. The color of the product has no practical significance, but can be used for marking phase and neutral conductors and grounding wires.
PPE clamps significantly speed up installation, and due to the insulated housing, they do not require additional insulation. True, their connection quality is somewhat lower than that of screw terminal blocks. Therefore, other things being equal, preference should still be given to the latter.
Twisting. Twisted connection of wires.
Twisting bare wires as a connection method is not included in the “Electrical Installation Rules” (PUE). But despite this, many experienced electricians consider a correctly performed twist as a completely reliable and high-quality connection, arguing that the transition resistance in it is practically no different from the resistance in the whole conductor. Be that as it may, good twisting can be considered one of the stages of connecting wires by soldering, welding or PPE caps. Therefore, high-quality twisting is the key to the reliability of all electrical wiring.
If the wires are connected according to the “as it happens” principle, a large transition resistance may arise at the point of their contact with all the negative consequences.
Depending on the type of connection, twisting can be performed in several ways, which, with a small transition resistance, can provide a completely reliable connection.
First, the insulation is carefully removed without damaging the wire core. Sections of cores exposed to a length of at least 3-4 cm are treated with acetone or white spirit and cleaned sandpaper to a metallic shine and twist tightly with pliers.
Crimping method Widely used to make reliable connections in junction boxes. In this case, the ends of the wires are stripped, combined into appropriate bundles and pressed. The connection after crimping is protected with electrical tape or heat shrink tubing. It is one-piece and does not require maintenance.
Crimping It is considered one of the most reliable methods of connecting wires. Such connections are made using sleeves by continuous compression or local pressing with special tools (press jaws), into which replaceable dies and punches are inserted. In this case, the wall of the sleeve is pressed (or compressed) into the cable cores to form a reliable electrical contact. Crimping can be done by local pressing or continuous compression. Continuous crimping is usually done in the shape of a hexagon.
Before crimping, it is recommended to treat copper wires with a thick lubricant containing technical petroleum jelly. This lubrication reduces friction and reduces the risk of damage to the core. Non-conducting lubricant does not increase the contact resistance of the connection, since if the technology is followed, the lubricant is completely displaced from the contact point, remaining only in the voids.
For crimping, manual press pliers are most often used. In the most common case, the working parts of these tools are dies and punches. In general, the punch is a movable element that produces local indentation on the sleeve, and the matrix is a shaped fixed bracket that perceives the pressure of the sleeve. Dies and punches can be replaceable or adjustable (designed for different cross-sections).
When installing ordinary home wiring, small crimping pliers with shaped jaws are usually used.
As a sleeve for crimping, you can, of course, use any copper tube, but it is better to use special sleeves made of electrical copper, the length of which corresponds to the conditions for reliable connection.
When crimping, the wires can be inserted into the sleeve either from opposite sides until mutual contact is strictly in the middle, or from one side. But in any case, the total cross-section of the wires must correspond to the inner diameter of the sleeve.
Electricity is not an area where you need to save. It is advisable to do everything carefully, select high-quality materials, and take a balanced approach to the choice of sizes/diameters/values. Let's start with the fact that even the conductors must be connected correctly. And choosing ways to connect wires is not as easy as it seems.
There are about a dozen ways to connect wires. In general, they can be divided into two groups: those that require special equipment or specific skills and those that can be successfully used by anyone. House master— they do not require any special skills.
The first group includes:
- Soldering. When connecting wires of small diameter in the amount of -2-3 pieces - very reliable method. True, it requires a soldering iron and some skills in using it.
- Welding. You need a welding machine and special electrodes. But the contact is reliable - the conductors are fused into a monolith.
- Crimping with sleeves. You need sleeves and special pliers. The sleeves are selected according to certain rules that you need to know. The connection is reliable, but it will have to be cut to re-seal.
All these methods of connecting wires are performed mainly by specialists. If you have skills in handling a soldering iron or welding machine, after practicing on unnecessary scraps, you can make them yourself.
Some methods of connecting wires are more popular, others less so.
Methods of connecting wires that do not require any specific skills are becoming increasingly popular. Their advantage is quick installation and reliable connection. Disadvantage - you need “connectors” - terminal blocks, clamps, bolts. Some of them cost quite a lot of money (Wago terminal blocks, for example), although there are also inexpensive options - screw terminal blocks.
So here are ways to connect wires that are easy to implement:
There are two opposing opinions among professionals. Some believe that new methods of connecting wires - clamps - are the best solution, as they speed up installation without compromising the quality of the connection. Others say that the springs will eventually weaken and contact will deteriorate. In this matter, the choice is yours.
Technical nuances of different types of wire connections
All types of wire connections described above are used when laying electrical wiring, but the specific type is selected based on several characteristics:
Let's consider each connection method, the technology for its implementation and the advisability of use in various situations.
Soldering electrical wires
One of the oldest and most widespread types of connection. To work you will need rosin, solder and a soldering iron. The soldering process is as follows:
Actually, this completes the soldering of electrical wires. Not the best difficult process but requires certain skills. The main thing is to heat the joint enough so that the solder flows between all the wires. In this case, you must not overheat, otherwise the insulation will melt. This is where the art lies - not to burn the insulation, but to ensure reliable contact.
When can soldering be used? This method of connecting wires works well in low-current electrical applications. When connecting wires in a junction box, it is no longer very convenient. Especially if there are a lot of wires and/or they are of large diameter. Soldering such a twist is not a task for beginners. In addition, when trying to make a connection in a junction box, the soldering begins to break down. To the point where some wires fall off. In general, the method is good for connecting conductors of small diameters.
Welding conductors in electrical connections
One of the most reliable methods of connecting wires is welding. During this process, the metal of individual conductors is brought to the melting point, mixed, and after cooling it forms a monolith. This method works very well with large diameters or with a large number of connected conductors. It is distinguished by not just excellent contact, which does not weaken or change its characteristics over time. It is also mechanically very strong - the fused part does not allow the connection to fall apart even under heavy loads.
A drop at the end of the twist is molten aluminum
There are also disadvantages. The first is that the conductors are fused, that is, the connection is absolutely permanent. If you need to re-seal it, you have to remove the fused part and start all over again. To be able to do this, you must always leave a small gap along the length of the wires. The second drawback is that you need a welding machine, skills in handling it, and special electrodes for welding aluminum or copper. The main task in this case is not to burn the insulation, but to melt the conductors. To make this possible, they are stripped of about 10 cm of insulation, tightly twisted into a bundle, and then welded at the very end.
Another disadvantage of welding wires is that it is a labor-intensive process, which also requires pinpoint precision in handling the welding machine. Due to the combination of these qualities, many professional electricians do not like this method. If you do the wiring “for yourself” and know how to handle the equipment, you can spend some time. Just practice first on scraps, select the current strength and welding time. Only after you get everything perfect several times can you start welding wires “in real life”.
Crimping
Another method that requires special equipment is crimping wires with sleeves. There are copper and aluminum sleeves of different diameters. The material is selected depending on the material of the conductor, and the size is selected according to the diameter and number of wires in a particular connection. They should fill almost the entire space inside the sleeve, but at the same time there should be free place. The quality of contact depends on the correct choice of sleeve size. This is the main difficulty with this method of connecting wires: the sleeve should not be too large or too small.
The technology of work is as follows:
- The conductors are stripped of insulation (the length of the stripped section is slightly longer than the length of the sleeve).
- Each conductor is stripped to bare metal (we remove oxides with fine-grain sandpaper).
- The wires are twisted and inserted into the sleeve.
- They are crimped with special pliers.
It seems to be simple, but it is in the selection of the sleeve and the presence of pliers that the whole difficulty lies. You can, of course, try to crimp it with pliers or pliers. But it is impossible to guarantee normal contact in this case.
Twist
In the first section of the article, we deliberately omitted twisting the wires. According to the current standard, it cannot be used, since it does not provide proper contact and reliability of the connection. This method can replace any other methods of connecting wires.
Yes, wiring was done on twists 20-30 years ago and everything worked perfectly. But what were the loads on the networks then, and what are they now... Today, the amount of equipment in ordinary apartment or a private home has increased significantly and most equipment is demanding on power supply. Some types simply will not work at reduced voltage.
Why is twisting so bad? Wires twisted into a bundle do not make good enough contact. At first, everything is fine, but over time the metal becomes covered with an oxide film, which significantly worsens the contact. If there is insufficient contact, the joint begins to heat up; an increase in temperature causes more active formation of an oxide film, which further worsens the contact. At some point, the twist becomes very hot, which can lead to a fire. It is for this reason that it is better to choose any other method. There are some that can be done even faster and easier, but which are more reliable.
Connection insulation
All the methods of connecting wires described above - welding, soldering, crimping with a sleeve - provide for their insulation, since the exposed conductors must be protected. For these purposes, electrical tape or heat-shrinkable tubes are used.
Everyone probably knows how to use electrical tape, but we’ll tell you a little about heat-shrinkable tubes. This is a hollow polymer tube, which, with increasing temperature, significantly reduces its diameter (2-6 times, depending on the type). The size is selected so that the pre-shrink volume is larger than the diameter of the insulated wires, and the post-shrink volume is smaller. In this case, a tight fit of the polymer is ensured, which guarantees a good degree of insulation.
Heat-shrinkable tubes for insulating conductors can be of different diameters and colors
In addition to size, heat shrink tubes are selected according to special characteristics. They are:
- heat resistant;
- light-stabilized (for outdoor use);
- oil-gasoline resistant;
- resistant to chemicals.
The cost of heat-shrinkable tubes is not very high - from $0.5 to $0.75 per 1 meter. Their length should be slightly longer than the length of the bare conductors - so that one edge of the tube stretches over the insulation of the conductors by about 0.5 cm, and the other sticks out by 0.5-1 cm. After the tube is stretched, take a heat source (you can use a lighter) and heat the tube. The heating temperature can be different - from 60°C to +120°C. After the joint is tightened, the heating stops, after which the polymer quickly cools.
Insulating wires with heat-shrinkable tubing takes little time—seconds count—and the quality of the insulation is high. Sometimes, for greater reliability, two tubes can be used - a slightly smaller and a slightly larger diameter. In this case, first one tube is put on and warmed up, then the second. Such connections can be used even in water.
Terminal blocks
This method is also preferred by electricians, but can be easily used by a person who can hold a regular screwdriver. This is one of the first ways to connect electrical wires without soldering. Today, on almost every electrical appliance you can see a version of this connection - this is the output block to which the power cord is connected.
Terminal blocks are a contact plate that is sealed in a plastic (polymer) or carbolite housing. They cost very little and are available in almost any store that sells electrical goods.
Terminal blocks are convenient, inexpensive, allow you to connect copper and aluminum wires, conductors of different diameters, single- and multi-core
The connection occurs literally in seconds. The insulation is removed from the conductor (approximately 0.5-0.7 cm), and the oxide film is removed. Two conductors are inserted into the socket - one opposite the other - and secured with bolts. These bolts press the metal against the contact plate, making the connection.
The advantage of this connection method: you can connect wires of different sections, single-core to multi-core. The disadvantage is that only a pair of wires are connected. To connect three or more, jumpers must be installed.
PPE caps
Another way to connect wires that does not require special skills is to install PPE caps. They are a plastic cone-shaped body with a spring sealed inside. They come in different sizes - from 0 to 5. You can connect wires different diameters— on each package there is written the minimum, maximum and minimum total cross-section of the wires to be connected. In addition, there are cases simply in the form of a cone, and some with stops “ears” that make their installation easier. When choosing, pay attention to the quality of the plastic - it should not bend.
Connecting wires using PPE is very simple: strip the insulation, collect the wires into a bundle, insert them inside the cap and start twisting. A spring inside the cap grips the conductors, helping to twist them. The result is a twist that outside wrapped with spring wire. That is, the contact turns out to be very high quality and good. This method of connecting wires with PPE caps has been used for a long time in Europe and America; it came to us about 10 years ago.
If you need ways to connect wires without welding, consider PPE
There is another way: first the wires are twisted, then caps are put on them. This method was invented by the Russian company that produces these wire connectors - KZT. But this technique requires more time, and the quality of the connection is no different.
There is one more point: how long to strip the insulation from the wires. Manufacturers give clear instructions on this matter - each size has its own length of exposed conductors. It is designed so that all conductors without insulation are inside the housing. If you do this, the connection does not require additional insulation, which greatly speeds up the process. In addition, the expanded lower part does not interfere with heat dissipation and such a connection heats up less.
Practicing electricians advise stripping the wires by 5-10 cm, and insulating the twist that remains without insulation. This is argued by the fact that the contact area with this option is larger. It is true, but this option heats up more. And the standard solution is reliable. There are no problems with contact (if the quality of PPE is normal).
Wago Clamps
The heated debates flared up specifically about Vago. Some people absolutely love this product, while others don’t. Moreover, no less categorically. Opponents of using the Wago don't like the fact that the contact is based on a spring. They say that it may weaken. This will lead to poor contact and overheating. And they show a photo with melted clamps. Proponents of this method conduct tests and comparisons and say that a properly selected branded clamp lasts for many years without signs of contact deterioration. And manufacturers say that, if the technology is followed, Wago terminal blocks can be used for 25-35 years. It is important to choose the right type and parameters and not buy a fake (there are a lot of them).
There are two types of Vago clamps. The first series is slightly less expensive, called Wago. These clamps are suitable for connecting single-core and stranded wires with a cross-section of 0.5-4 mm2. For conductors of smaller or larger cross-sections there is another series - Cage Clamp. It has a very wide range of use - 0.08-35 mm2, but also high cost. In any case, contact is ensured by a contact plate made of good copper. Special shape plate allows you to achieve reliable contact.
Detachable
In addition, Vago spring-loaded clamps are detachable (222 series) and permanent (773 and 273 series). Detachable ones are convenient to install in places where changes to the network configuration are possible. For example, in junction boxes. They have levers with which the wires are clamped or released. Wago detachable terminal blocks can connect from 2 to 5 conductors. Moreover, they can be different sections, type (single-core and stranded). The order of connecting the wires is as follows:
We repeat the same operation with the other wire(s). All this takes a matter of seconds. Very fast and convenient. It's not surprising that many professional electricians have forgotten other ways to connect wires.
One-piece
One-piece series differ in structure: there is a clamp body and a cap. The cap can be made of transparent polymer (773 series) or opaque plastic (223). The housing has holes into which wires stripped of insulation are inserted.
To ensure normal contact, you just need to remove the insulation correctly - exactly 12-13 mm. These are the requirements set by the manufacturer. After the conductor is inserted, its bare part should be in the terminal block, and the insulation should rest against the housing. Under such conditions, contact will be reliable.
Bolted connection
Another type of connection of electrical wires with solid experience is bolted. It is called so because a bolt, nut and several washers are used to connect the wires. Contact through the use of washers is quite good, but the entire structure takes up a lot of space and is inconvenient to install. It is mainly used if it is necessary to connect conductors made of different metals - aluminum and copper.
The order of assembling the connection is as follows:
- We strip the wires of insulation.
- From the stripped part we form a loop, the diameter of which is equal to the diameter of the bolt.
- We put it on the bolt in this order
- washer (it rests on the bolt head);
- one of the conductors;
- another washer;
- second conductor;
- third washer;
- We tighten everything with a nut.
This way you can connect not only two, but also three or more wires. Please note that you must not only tighten the nut by hand. You have to use wrenches and put in a lot of effort.
The best ways to connect wires for different occasions
Since different wires can be connected and they can be used in different conditions, then the best way you need to choose taking into account all these nuances. Here are the most common situations:
These are the most common options for non-standard connections.
To joints without soldering or fastening together. Unfortunately, this dream will never come true. No one would agree to have so many cables used in their apartment. And this pleasure will cost a tidy sum, because a lot of wiring will be required. This is the main reason that the network has many contacts. In each average apartment there may be up to hundreds of such associations. It should be noted that wiring problems most often occur in the places where the ends of the wires touch. In order to connect contacts correctly and safely, it is necessary to carefully study all the methods and options that are practiced by electricians.
Any living space today has wiringHow to connect wiring in a house
So, if the question arises of how to connect wires at home, it is best to turn to the bible of every self-respecting electrician - the Electrical Installation Rules (ELR). Paragraph 2.1.21 of this reference book states that it is best to use the following methods:
- soldering;
- welding;
- crimping;
- bolted connection.
But other methods are also practiced that are not listed here. Twisting remains illegal, but connections with screws, insulating clamps such as PPE, and WAGO terminals are, one way or another, permitted. Let's look at each of them in more detail.
Twist
Be that as it may, the method that uses twisting is now the most popular among electricians and those users who are trying to create a connection of wires in their apartment. The danger of this technique is the high risk of fire. It can happen due to overheating of the cable, which is under the influence of high resistance caused by the weakening of the twist itself.
But it also needs to be said that with proper operations, the twisting will last for decades. If it is not possible for you to use other methods, then twisting is exactly what you will need. The only condition is to be careful and do everything right.
You should not use twisting in cases where you can create a wire connection using another method. If technical support of electrical circuits is your job responsibilities or you simply do it for money, then the use of twisting may entail liability under the Criminal Code. You also have the right not to pay for the work of the craftsmen who used it.
You cannot use methods for connecting wires where different types of metal are used. Also pay attention to the number of cores at each end - you cannot twist a single-core cable with a multi-core one. To connect the ends correctly and efficiently using this method, first remove the insulation from the end by 6–8 cm. Then fold the wires perpendicular to each other and twist. It is best to do this with pliers, this way you will achieve maximum twist density. But if you are dealing with small cross-section wires, then this can be done by hand. The length of the twist should ultimately be greater than 10 diameters of the wires you connected.
The final stage of twisting will be insulation. You will need caps, PVC or heat shrink tubing, or simple electrical tape. Be sure to ensure that your insulation overlaps the original insulation. This way you will protect the system from moisture.
Soldering
The soldering method requires a significant amount of theoretical and practical skills in working with equipment and wires. Experienced electricians know what's best good twist than bad soldering. First you need to rid the wires of oxidation, tin them, and then twist them. Moreover, you don’t need to twist as much as in the previous case. Flux and solder also need to be carefully selected, since different metals require different materials. In terms of time, connecting wires in this way is the longest, but the result is better than using other methods. After the wires have cooled, they must be insulated using any available method.
Welding
This method is the most common and popular today. As for practical skills, this method can be considered the fastest and most reliable. You can use both variable and D.C. voltage from 15 to 30 V. If you are dealing with two wires with a diameter of up to 1.5 sq. mm, use a current of 70 A. If you need to connect three wires, then use 90 A. Three wires with a diameter of up to 2.5 square meters. mm require a current of 100 A, and four - 120 A.
First you need to strip the wires of insulation at a distance of 6 cm from the edge. Then twist them as if twisting, but leave 6mm at the ends. Straighten them and place them parallel.
Remember that when working with it, you must adhere to all fire safety rules and regulations, and also use all types of protective equipment (gloves, clothing, goggles or mask).
Place the ends of the wires into the clamp and begin welding. You need to achieve a melt ball. It should extend to the twist itself. Welding should be carried out no longer than 3 seconds, otherwise you risk breaking the insulation. After you have connected the wires and they have cooled completely, insulate them.
PPE is made in the form of a cap. Inside the connecting wire there is a steel wire bent in the shape of a cone. Modern manufacturers they also fill the cavity of the cap with a special mixture, which protects the connection from moisture getting inside. The first condition for high-quality use of PPE is the correctly selected clamp size. You can read the parameters on the product packaging in more detail.
To make a connection of wires in this way, you need to strip them of their original insulation at a distance that is equal to the length of the cap. Next, insert the ends of the wires into the clamp and fix them there according to the mechanism. Most installers and electricians use the twisting technique for reliability, and place such clamps on top.
The advantage of this method over others is that this way you can simultaneously connect the wires and isolate the twisted points. But there is also a minus - it is unreliable, since the clamp constantly unwinds.
Screw clamps are very popular when conducting minor works in the apartment. The advantage of this method is the speed and accuracy of the connection. You don't have to insulate the wires. Also, using the clamping technique, you can connect wires of different metals.
The disadvantages of this technique include, first of all, the fact that you cannot connect wires that are made of different metals. They must first be soldered or combined with a tip. Also, such clamps are not entirely reliable - they need to be tightened periodically. So they are best used in places where there is easy, constant access.
The terminal block is a relatively new method of connecting wires. It is based on the use of special clamps that have been developed by German company WAGO. You can now find many analogues on the market, but they are inferior in quality and reliability. If you decide, then it is best to buy terminals in specialized certified supermarkets. You are offered many options to choose from for a variety of sizes, number of cores, and so on.
The advantage of this method is ease of use, no need to apply optional equipment or possess certain skills. You can quickly and efficiently connect wires and insulate them using one clamp. WAGO products have passed all the necessary tests and are the world leader in the production of wire clamps.
The crimping method involves using a sleeve or lug to connect the wires. This technology stands out among others for its reliability. All that is required of you is to choose the right sleeves and be able to use special equipment - pliers (hydraulic or electric) or a press.
Bolted connections
This method is best used when working with networks with high current. The idea is simple - wires are laid between two washers on a bolt, and then tightly fixed with a nut of a suitable size. Moreover, you can connect aluminum and copper wire if you use steel nuts. However, this method is not particularly popular because it does not look aesthetically pleasing.
Finally, we need to remind you that all wire connections, no matter how you do it, must be accessible for correction and inspection. If you've ever connected two or more wires yourself, please share your comments below.
We have to do these procedures in the process of repairing apartment electrical wiring or when laying new electrical wiring, as well as when connecting wires in junction boxes. In order to splice, branch or connect electrical cables, we need the following tools: pliers, wire cutters, construction knife, electrical tape and, of course, the wires themselves. It is advisable to have two rolls of electrical tape of different colors.
We will show you the process of connecting wires simply using scraps. These wires will be in your wall either in electrical plastic boxes or laid in some other way.
Connecting electrical cables
Let's start by connecting the electrical wires. Let's assume that we have three wires going into the electrical box, and they need to be connected to each other. How it's done? First you need to cut off the excess cable and leave the cable at such a length that it does not interfere with the placement of cables in electrical box, but at the same time it was not very short, because the cable is too short and cannot be properly stripped, and it will not be possible to connect properly. It should extend about 5 cm out of the box, then we will trim it anyway.
Now we do the following: we strip each cable to a length of approximately 2–2.5 cm. We carefully cut it, trying not to damage the inner conductor. Here the technology is the same for all types of conductors - aluminum, copper, single-core and stranded.
We remove the insulation without damaging the cable, then be sure to strip the conductor, because most cables have it covered thin layer varnish to prevent corrosion of the conductive layer. We clean it with the end of the knife specially designed for this purpose, so as not to cut our hands or dull the knife.
We twist the veins. You can twist them in any direction you like.
To do this, you can use pliers or own hands, if you don't feel sorry for them. Naturally, only multi-core cables are twisted. If you have a single-core cable, then we simply strip it. We perform the same procedure with the second cable, then with the third: remove the insulation, strip it, twist it. Then we take two cables, lean them against the insulation and tightly twist them like this:
Why is this being done? First, we bite off the excess. We don’t need a strongly protruding twist, it’s inconvenient to insulate, and it won’t fit well in the box. Secondly, we get something like cold welding.
This is also very important, as it improves electrical contact and, therefore, the functionality of our wiring. With such a connection, our wiring will work much longer. Then we isolate the twist.
In order not to constantly check with an indicator probe whether it is phase or “zero,” it is best to mark the phase wire, for example, with red or brown electrical tape. As a rule, phase wires in electrical networks are designated with these colors, and the neutral cable is either black or blue. If you don’t have blue or black electrical tape, you can use yellow or some other kind. We take electrical tape, start about 1 cm along the insulation and wrap it as tightly as possible.
Then we wrap a second layer of electrical tape to create reliable insulation. The insulating tape will not only insulate the cable, but also hold it together, because with aluminum strands it often happens that the strand weakens over time. Aluminum oxidizes slightly and twisting becomes unreliable. If we insulate everything tightly, then the electrical tape will additionally secure this twist. The twist will last much longer; there will be no need to disassemble it after 5-6 years and twist it. Twisted and cut. This can be done with pliers or a construction knife.
One more point: it is recommended to insulate electrical boxes in such a way that there is access to the electrical contact:
What is it for? The cable remains insulated, that is, a short circuit will not occur, but when repairing this wiring, it will be very easy for you to check whether it is a phase or “zero”, whether there is a phase or not. This check is easy to carry out, but the insulation remains reliable and does not in any way affect the performance of the connection. This is very convenient during repairs, since you don’t have to unwind the insulation and, therefore, everything can be checked under voltage - you don’t need to turn off the electrical packages and then turn them on again. They just opened the box, checked it, and that’s it. Thus, we connected three wires. In the same way you can connect large quantity wires, as a rule, up to six. It will no longer work, because too much twisting becomes non-functional and inconvenient to use.
Splicing electrical cables
The cables have to be spliced in the electrical box or outside it. To do this, you need to strip these cables in the same way as in the previous example. We make cuts, remove insulation, and strip the cables. In order to splice the cables, we lay them crosswise:
We twist them, about 3-4 turns, and we get a fairly strong twist:
You can use pliers for this work. We work with them, trying to ensure that the cable does not diverge.
If desired, if you have a soldering iron, you can also solder this connection to give it additional strength. If you don’t have a soldering iron, you can do it this way. We begin to isolate the resulting twist. We take electrical tape, start about a centimeter before the connection and insulate it.
We also go about a centimeter from the other edge and return to improve the dielectric properties of our connection with a second layer. We bite off the excess electrical tape.
That's it - we spliced the cable.
Electrical cable branch
Suppose we have wiring in the wall that has already been installed earlier, but we forgot to install some kind of socket or switch. In order to install them, it is necessary to make a cable outlet, that is, connect to our central core.
For electrical connections, it is better to do this in a box, but in any case you will have to connect it with a branch. How to do it?
We take the outlet cable, remove the insulation in the same way as in the previously described cases, strip it, twist it. Then we prepare the central core. To do this, we remove the insulation in a certain area, also 1.5–2 centimeters, but the peculiarity here is that we remove the insulation not from the edge, but in the middle of the wire. Since this cable is not wound, the length of the stripped section will be shorter. We cut through the insulation in a circle on one side and the other:
Now, carefully, so as not to cut yourself, cut the insulation in the center, remove it and cut off the excess:
Here we have a prepared cable:
We clean it, if possible, twist it. But if the cable has already been laid, then it may not be possible to twist it. We have prepared the cable, take a branch, apply it to the left edge, insulation to insulation, and wind it tightly.
We try not to let anything stick out. The result is a fairly reliable branch:
We take the electrical tape, start a centimeter before the twist, go through one layer, move smoothly to our connection, and also go about a centimeter along the insulation.
Returning back, we wrap it not on the central cable, but on the branch:
Trim off the excess tape:
We ended up with this branch:
The central cable remained in its place, and the branch went to the outlet or switch. It should be remembered that all these procedures must be done with the voltage turned off! Take care of your health, and maybe your life. Such work with electrical wiring does not forgive mistakes!
All rights to the video belong to: Popular electronics / For the home electrician
