To create reliable contact between several copper wires, the twisting method is used. With its help, industrial and household electrical networks are equipped. Additionally, it is recommended to make a welded connection, which prevents the oxidation process between the cores and reduces the likelihood of the bundle unwinding. Reliable welding of copper wires with graphite electrodes is carried out after studying the basic rules.
Copper wire welding technology
The connection must be made only after the final installation of electrical wiring in the room. For convenience, the minimum length of the mounting ends should be 10 cm. Additionally, the distance between the wires and the possibility of their placement in a closed junction box are taken into account.
Technology for welding copper wires using graphite electrodes:
- Cleaning cores from insulation - at least 5 cm.
- Trimming the ends of the wires to remove possible oxide.
- Twisting. The wires should fit snugly against each other. To do this, it is recommended to fix them at the bottom, where there is insulation. Twisting is done using pliers or similar tools.
- Welding. It is performed using graphite electrodes.
- The final insulation of the twist occurs after the cores have cooled. They are then placed in a protective box.
This technology ensures reliable contact of the wires and also eliminates the need for periodic tightening of the connection of the wires. But to ensure this, you must select the right tools, consumables, and also calculate the optimal parameters.
Selecting electrodes and welding machine
The use of graphite wire electrodes is due to the relatively high temperature heating the working surface and the possibility of processing them. The choice of diameter depends on the planned current density. You also need to take into account their main technical characteristics.
Since the thickness of the welded twist can be different and depends on the number of cores and their diameter, there is no standard values current strength. Based on experience, to create a reliable connection from 3 copper wires with a cross-section of each 1.5 mm², a current of up to 90 A will be required. The exposure time is about 2 seconds. As a result, an even ball should form at the end of the twist. It is important to prevent the cores from overheating, which can lead to loss of insulation properties.
To perform welding, you must choose the right machine. You can choose from the following device types:
- Special machines for welding twists. The most common model is TS-700. Structurally, this is a standard inverter of small size and low power. Differences from other devices of this type are the ability to be worn on a belt while working.
- factory production. These can be any model whose characteristics meet the requirements for connecting copper wires.
- Homemade devices. Made from step-down transformers. Advantages - the ability to develop a design for performing narrow-profile work.
During welding, it is necessary to control the quality of the connection. There should be no shells, the formed ball should be heterogeneous.
Experts recommend using graphite electrodes without copper plating. This is due to the fact that when the angle burns out, its resistance will drop, which can lead to long contact. This will subsequently affect the quality of the connection.
It is also worth considering the following points:
- Before starting work, the end of the graphite electrode is processed - a recess is formed on it. This will facilitate the formation of a properly shaped adhesive ball.
- As an alternative to factory-made graphite electrodes, you can consider using current collectors used in trolleybuses or rods from batteries. They are relatively small in size and can be attached to the inverter handle.
- It is mandatory to use protective equipment (dark glasses), gloves and long sleeves.
Upon completion of welding of copper wires, it is necessary to check the quality of the connection. To do this, they put the maximum permissible load on the network and check whether there is heating on the twist. Only then can the connection be completely isolated.
When replacing wiring, it is better to weld or solder all twists of copper wires; I have even seen such welding on aluminum wires in the wiring of a house built in 1960. Even then, builders knew about welding wires... Read on to learn how to make a machine for welding copper strands with your own hands.
Wago terminals
Many will probably say: What about Wago type terminals? It's the 21st century!
I answer right away: I installed these “super terminals” when replacing the wiring in the apartment, and when I turned on the electric kettle, such a terminal melted, I really didn’t like it, I even took apart one such terminal and saw that the contact there was very thin.
Therefore, sometimes the good old twist will be more reliable than all this modern “good”!
At one time, of course, there were good dead-end terminals - you insert a twist there and tighten it with a screw - it turns out insulated and firmly fixed - an awesome thing, but now they have completely disappeared from sale. It's a shame 😥
How is welding copper wires better than soldering?
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It is also possible to solder copper wires, but the resistance of tin solder is tens of times higher than that of copper. In principle, everything works with soldering, but when large currents flow, there is a possibility of heating the section of the circuit with a higher resistance. Although in most cases electricians neglect this.
In the end, I decided to assemble a machine for welding copper wires.
The design of the machine for welding twists is not final, because according to advice good people from the Chipmaker.ru forum there is an opportunity to further improve this device.
Why do you need a welding machine?
My goals for this device were:
- welding copper wires when renovating an apartment (I’m not going to weld aluminum ones), i.e. within one box in each room, so I considered the length of the wires 3 meters sufficient
- to get as compact a machine as possible for welding twists, so I used a case from a computer power supply and a transformer from a microwave, which combines small size (considerable weight) and high power.
How to assemble a machine for welding twists with your own hands
So, how was the wire welding machine assembled?
I disassembled the transformer from the microwave, sawing it with a grinder at the welding points. I will not describe this process in detail, because... this has been done many, many times, and you can at least find a video on YouTube.
BUT, please note that a microwave transformer is dangerous to life! Those. it should not be connected to the network for testing until the secondary winding is removed, because The voltage on it is about 2000V and it can kill a person from a distance!
In general, the trans was cut, the secondary winding was thrown out, my own winding was wound with 6 mm square copper wire, I only got about 16 turns, either the trans was too small, or I’m not a very experienced winder, but oh well, after turning it on trans to the network, I received a voltage of 14 volts, which is normal for such welding (12-24v is needed). I then glued the trance core together with epoxy. At this point, work with the microwave transformer was completed.
I installed it in the case, I also installed 2 16A circuit breakers there (after the first welding experience, in order to know the maximum current consumption, it turned out to be 11A).
Why didn’t you install a two-terminal device?
And I assembled the welding wires from what was at hand. My motto: First use what is lying around idle, unless of course it spoils the design 🙂
I used 10 mm square stranded copper wires for the output.
One wire was soldered to the terminal of a graphite brush from a powerful electric motor (you can find such a brush on the market for 20-30 rubles). The holder for it was made from a file handle, into which I inserted a part in the shape of a key blank from a piece of 4mm steel; here, I think, you can just use an unnecessary key to the apartment where the money is :)
I heated the “key” and inserted it into the file handle, made a clamp from thin tin and used it to pull the brush to the handle. I also tied the wire to the holder using a regular tie (where would we be without it these days).
In a graphite brush, I drilled two holes of different diameters for the twists - this will make it more convenient to weld the twists so that a drop of copper does not try to jump off.
I made the second clamp like everyone else - from unnecessary pliers.
The wire was connected to them like this.
He took off one handle and ground off the iron part under a 10 mm circle, put a 10 mm copper bus on it, inserted a wire into the other end of the bus and soldered it all using flux for ferrous metal, tin, soldering iron and gas burner(I first heated the pliers with a torch, so that I could solder with a soldering iron later). The connection turned out to be strong, but if it breaks off, I’ll practice soldering again :) I put 2 heat shrinks on top, and in the end it turned out neat. I drilled 2 holes in the jaws of the pliers, 3 mm and 5 mm, to make it more convenient to clamp the twist.
I connected the wires to the transformer using 30A screw terminals, it seems...
I attached a green power indicator to the front, sawed a window for the machine guns in the case lid, glued pieces of linoleum to the inside of the case lid so that it would not rattle - this helped. Well, I made a handle for easy carrying of the device from an old door handle.
And below, I screwed the legs from the old Soviet equipment into the standard threaded holes.
Advantages and disadvantages of wire welding machine
- the device cooks quite well, the voltage is enough to ignite the arc and the transformer does not heat up from the microwave, but if you have a larger trans, it is better to wind the secondary winding with a 10 sq mm wire.
- The device turned out to be very compact, although I won’t say that it is light, because... A microwave transformer usually weighs 3-5 kg
- The device lacks a switch, because It is difficult to immediately hit a hole in graphite with a twist. It would be more convenient to first insert the twist into the hole and then turn on the welding, it would be better to place the button on the graphite terminal holder, I think I will implement this in the future...
- How to make a good terminal - you need to use a larger piece of graphite, for example a brush from a powerful engine or a brush from a trolleybus, several holes are drilled into it. Then a twist is put into these holes and then the drop will be smooth and beautiful, but if you boil the battery with an electrode, a drop will appear, but it tends to jump down. Also, the electrode from the battery smokes quite a bit and stinks, apparently due to various impurities.
- Keep in mind that when welding copper strands there will be smoke, a burning smell and the graphite electrode will sometimes catch fire, so it is better to weld with an open window.
- It is better to dip the twist in borax before welding and do not overheat the twist, because The insulation of the wires will begin to melt and the copper at the welding site will become brittle.
- Remember to cut the ends of the twisted wires evenly so that they are the same length.
- If you make a choke, the welding will be more gentle (I will try this later).
In general, I got an excellent machine for welding twists and a lot of pleasure from making it.
And wait for updates to this article, because... The device will still be improved...
Photo of a machine for welding copper strands
Most often for production electrical wiring use copper wires. The aluminum analogue is practically not used. Welding of wires made of copper is done using not only alternating voltage, but also DC. Its voltage is within the following range: 12–36 V. In this case, the current supply must change. Welding wires with an inverter has its own characteristics.
Inverter type devices
The advantages of inverter units are well known to specialists. Certain models are equipped with a strap that allows you to carry the inverter on your shoulder. This makes it possible to carry out welding work with twisting in a junction box while standing on a stepladder. The inverter can be connected to household electrical wiring, since the device has low power consumption.
Inverters have a wide range of electric current regulation. Their arc is very stable and ignites perfectly at low welding currents. For this reason, even an untrained electric gas welder can quickly achieve an amazing effect and achieve optimal quality of wire welding.
Household welding devices are marked with the abbreviation MMA. Then numbers are indicated indicating the operating current - 200 or 250 V. The professional device operates in a temperature range of up to 150 degrees. The home device has a spectrum from 0 to +30. Another difference between a home device and a professional and industrial device is the duration of the operating cycle.
A professional type inverter will operate for 8 hours with short breaks, an industrial type - 24 hours with a break of 30 minutes. The device, intended for household use, operates without interruption for 30 minutes, and then cools down for an hour.
When welding a copper type cable, a special copper-plated carbon electrode is used, which is popularly called a “pencil”. If you don't have a carbon electrode, you can take a standard carbon rod from an unusable battery. Welding current, depending on the cross-section and number of wires, is used at different voltages. A suitable mode is one in which the electrode does not stick to the welding area and the arc is stable.
Process
Welding of wires is carried out using technology, thanks to which an optimal result is obtained. Welding wires with an inverter is carried out in stages:
- It is necessary to strip the cable of external insulation.
- Then they make a twist, cutting it so that the ends of the wires are at the same level, while the minimum twist length should be 50 mm.
- Then you need to install a copper clamp that removes heat and turn on the inverter.
- Bring the tip of the charcoal pencil to the finished twist, clamped in the holder, and connect the wires by welding.
- After a few seconds, a small ball of molten metal will form at the end of the twist, after which the work is stopped. To prevent the insulating shell from melting during operation, work with each twist for no more than 2 seconds.
- After the cable has completely cooled, the wires are insulated using ordinary insulating tape or heat-shrink tubing.
Specifics of welding work with aluminum wires
The most reliable method of welding the twist end is considered to be the spot method. The advantage of this method is that when welding work Ah there is a fusion of metal conductors. And if with other options a transition resistance of the contact area may arise, then with the point mode this does not happen. Electrically welded wires are durable and do not require periodic maintenance, inspection or repair.
Possible complications of work
When working with aluminum cables, a number of difficulties arise:
- It is difficult to make a high-quality connection due to the oxide film that rapidly forms on the metal. This makes it difficult to obtain a uniform connection of wires.
- The increased fluidity of aluminum in the molten state makes it difficult to achieve good quality welds when welding tight joints.
- Metal shrinkage should be taken into account. But the obtained result can always be improved with additional twist processing.
Carry out actions with aluminum cable at home - difficult task. The correct welding mode must be carefully selected. There is a misconception that inverters have a constant output voltage.
In fact, the device is equipped with an electric current control and the voltage can be lowered, depending on the diameter of the wire:
| Voltage,B | Diameter of wires, mm |
| 25 | 0,5–1,0 |
| 20 | 0,3–0,5 |
| 12 | 0,1–0,3 |
| 10 | 0,05–0,1 |
You should also choose the correct diameter of the electrode, depending on the area of the core:
The magnitude of the welding electric current varies depending on the number of wires and their diameter:
When welding with alternating current, it is difficult to achieve a good result and it takes a lot of skill to get a quality connection. This is why a non-professional will need good device to master the basics.
When carrying out electrical installation work, in particular when installing, repairing or replacing electrical wiring, it is impossible to do without wire connections. They are always found in junction boxes; they are used when replacing a faulty section of the circuit.
One type of reliable permanent connection is strand welding, when the wires are first twisted and then welded.
There are quite a few ways to connect wires - using screw and self-clamping terminals, crimp sleeves, a bolt and nut (through a washer). But most often, the ends of the wires are connected by twisting, that is, they are simply twisted.
All of the above methods have one significant drawback. Even if the rules and technology of work are observed, the area of the contact zone of two conductors turns out to be less than the working cross-section of the core.
At a sufficiently high load (not exceeding, however, the permissible load), the contact area will heat up. Which can lead to insulation melting, short circuit, or fire.
Twists have an advantage over other types of connections, since twists can increase the contact area of the wires. To do this, it is enough to solder the ends of the cores in a twist or weld them.
Soldering connections are quite labor intensive. And if you consider that distribution boxes, as a rule, are located at a level of 2.3-2.5 meters from the floor, it is very inconvenient to carry out the work.
After all, in addition to a soldering iron, you need to have solder with you, and sometimes also flux. And all this is at its best. In addition, in order for the connection to be of high quality, it must be heated for quite a long time, which also does not speed up the work process.
Advantages of the method
Twist welding is a more technologically advanced type of connection. It is faster and does not require any filler material. The melted ends of twisted wires form a strong connection that is not subject to electrochemical corrosion.
Welding requires additional equipment, and this is the only drawback. In the absence of a special welding machine for welding twists, you can, or you can make such a machine with your own hands.
A special feature of twist welding is that it is carried out with a carbon non-consumable electrode, which for convenience is better sharpened to a cone.
Process technology
Before connecting, the ends of the wires to be welded must be cleared of 7-8 cm of insulation. After this, they are twisted and cut so that the length of the twist is about 5 cm. A heat sink is installed on it near the insulation, which can be used as an electric alligator clip.
Next, “ground” is applied to the wires and by briefly touching the end of the twist with the electrode, an arc is excited, which melts the copper conductors. The duration of the arc should not exceed 1-2 s, otherwise the twist will become very hot and the insulation may melt.
As a result of welding, at the end of the twist you should get a homogeneous frozen drop of metal in the shape of a ball. The cooled connection is isolated by any acceptable method. At the moment, heat-shrinkable tubing is popular, which is first placed on one of the wires.
Using an inverter device
To weld twists, you can use an inverter-type welding machine. The advantages of such devices are that, with a relatively low weight, they have significant welding power, while consuming a small amount of electricity.
This allows you to use inverter devices by connecting them to a household AC network without fear of voltage surges and drops. Inverters provide excellent output current parameters, which allows you to maintain an even and powerful arc.
The current value may vary depending on the core material and cross-section. Since aluminum cables with aluminum conductors are currently not used for internal electrical wiring, the parameters of the welding machine can be selected based on the requirements for welding copper conductors.
Example requirements are:
- for welding two wires with a cross-section of 1.5 mm², a current value of 70-75 A is required;
- the twisting of three such wires is welded with a current of 80-90 A;
- two or three wires with a cross-section of 2.5 mm² need to be welded with a current of 80-100 A;
- three or four of the same wires are connected using a current of 100-120 A.
Due to the high cost of inverter welding machines, it is unprofitable to purchase them to perform only strand welding. If you use some parts that can be easily purchased or removed from old electrical appliances, making a device for welding twists with your own hands will not be particularly difficult.
Homemade apparatus
The main component when assembling a machine for twist welding is a transformer with a power of at least 600 W, with an output voltage of 12-36 V. It must provide such voltage when connecting a supply voltage of 220-230 V.
When assembling the device, a durable metal case is required suitable sizes, in which it is necessary to provide the possibility of installing a fuse or circuit breaker rated 16 A.
The supply voltage to the transformer must be supplied by a cable with copper conductors and a cross-section of at least 1.5 mm². It is better to use a KG 3x1.5 cable with rubber insulation for this. The device body and the transformer core must be connected to the grounding conductor.
To connect the transformer to the ground contact and the holder, two wires with a cross-section of 10.0 mm² are used, for example KG 1x10. Their length should be as short as possible to avoid current loss. The holder can be used from any used welding machine.
A carbon electrode can be made by disassembling an old 373 battery. The core, also known as the positive electrode, is perfect for this purpose.
If you cannot get such a core, you can purchase carbon brushes for electric motors used in electrical appliances or power tools at the store. The brush is clamped into the holder and sharpened into a cone shape.
It is convenient to use pliers as a ground, connecting one of their handles to the transformer with a KG 1x10 wire. After this, the handles must be insulated. This device will allow you to comfortably hold the twist while welding. At the same time, the pliers will also act as a heat sink.
Security measures
Welding twists homemade device The efficiency is not inferior to welding with an inverter machine. When carrying out work, it is necessary to take into account harmful factors that appear during normal welding.
It is necessary to use shields with light filters to protect against ultraviolet radiation, gloves and clothing made of fireproof material. In addition, it is necessary to ensure compliance with fire safety measures.
Proper use of equipment and adherence to technology, as well as safety measures when working with welding, will allow you to obtain a reliable connection of cables. Ultimately, the reliability of all electrical wiring increases and the period of its trouble-free use increases.
Today we will look at a machine for welding copper and aluminum wires, and consider the technology of the welding process. Let's learn how to make a welding machine with our own hands.
Description of the welding process
Highest quality connection electrical wires can be done by welding them. High-quality welding guarantees reliability and durability of the connection. To weld wires, you need low electrical contact resistance. Welding requires special equipment in the form of a transformer or inverter.
The welding process itself is not complicated. First, the twisting of the wires is prepared. This work consists of stripping the connecting ends of the wire from insulation. You need to strip it to a length of up to ten centimeters. After stripping the cores, they must be twisted together. The result is a twist approximately 5 cm long. The end of the twist is cut off with pliers to align the end.
After you have prepared the twist, you need to put the wire welding machine into working condition. To do this, the cable coming from the holder is connected to the positive terminal on the device. The ground cable is connected to the terminal with the minus sign.
For welding you will need graphite electrodes. If there are no electrodes, then you can, instead, use brushes from the engine commutator or a graphite rod from a battery.
When welding, you must wear a protective mask or goggles and gloves.
When everything is prepared for welding, the end of the grounding cable is connected to the twist at some distance from the end. You can attach it using pliers, holding them in your left hand. In the right hand there is a holder with an electrode. The end of the electrode is brought to the end of the twist for 1-2 seconds. At this time, the welder usually notices the appearance of a red glow and moves the electrode to the side. If a frozen alloy in the form of a ball has formed at the welding site, and rainbow tints appear on the twist, then the welding was successful. The cooling field of the twist from welding must be insulated.
The current strength of the device is adjusted depending on the cross-section of the wires, the number of wires, and the thickness of the twist.
On video: The process of welding copper wires
Before twisting the cable, it must be cleared of insulation. The insulation is removed from the end of the wire to a length of up to 10 cm. Then the ends of the wire are connected by twisting. The length of the twist will be somewhere around 5 cm. To ensure that the end of the twist is even, it is cut off with wire cutters.
After preparing the twist, welding is prepared. The holder wire is connected to the terminal with a plus sign. The ground wire is connected to the negative terminal. After this, they begin to weld the twist. Welding must be done wearing a protective mask or goggles. With one hand, using pliers, the ground wire is pressed against the twist at some distance from the end. In the other hand there is a holder with an electrode. You need to touch the end of the twist with the end of the electrode for 1-2 seconds. At the same time, you need to notice with your eyes the moment when a red glow appears on the welded area. The rounded surface formed during welding of the ball and the rainbow tints on the twist indicate good welding. When the twist cools down after welding, it must be insulated.
Welding aluminum wires
When welding aluminum wires, it is necessary to prepare the twist in the same way as when preparing the twist of copper wires. Then the welding machine is ready for operation. The welding process is the same as when welding copper strands. After welding and twisting, it must be treated with a solvent, varnished and insulated.
Aluminum wires are welded using devices with voltages up to twenty volts. The arc used is not large. This is due to the low melting point of aluminum.
Inverter devices
The most reliable type of connecting electrical wires is welding using direct and alternating current, voltage from 12 to 36 V. For welding, electricians are increasingly using inverter welding machines. They are economical, lightweight, easy to carry and use. To weld wires, you can use graphite or simple carbon rods from a battery. You can set the current mode on the device, taking into account the diameter and number of wires being welded
How to choose a device
Preference is given to a welding inverter. Its main advantages are: wide range, the ability to softly regulate current, stability in operation, small size and weight.
For welding wires, you can choose a universal inverter machine. This device is the most modern. With this device you can perform all kinds of welding, and not just wires. When choosing a device, you need to look at the power source and its power. For work at home, a device with a power of 4 - 5 kW, with a current strength of up to 160 A, is suitable. It is advisable to have a “hot start”. It is needed to protect against sticking during welding and voltage surges. Such a device is useful for welding wires and for performing other welding work at home. Another advantage is that it is easy to use and does not require great skills. The disadvantages include its high price.
In practice, electricians use compact, portable, easy-to-use DC machines for welding wires.
Welding transformers are compact and inexpensive. Transformers with a power of 500 W or more and 25 V secondary voltage can be used.
DIY wire welding machine
Do you want to make a wire welding machine? Don't know how? It's done like this. Get a strong magnet and copper wire, insulated with fiberglass or cotton. It is needed for the transformer core. It is desirable that its cross-sectional area is no more than 50 square centimeters. If desired, you can also do the wire wrapping yourself. The required material is taken, wound on a wire, coated with electrical varnish and the primary winding is ready. The core is made in a U-shape for convenient winding of wire. It must have a rod structure. The reel frame can be made of PCB or cardboard. The secondary winding is wound on top of the primary winding. After applying the winding to one side of the coil, it is applied in the same way to the other half. If you place cardboard or fiberglass between the layers of the winding, the quality of the insulation will improve. A copper wire welding machine is connected to the network to measure the voltage on the secondary winding. It should be about 60 V. If it is much more or less, then by decreasing or increasing the winding, you can set the desired voltage value. A cable is connected to the primary winding. It must be two-wire. Instead, you can use an internal wire. A PRG wire is connected to the terminals of the secondary winding. The primary winding is used to receive current from the mains at 220 W through the cable. The secondary winding is used directly for welding.
On video: Do-it-yourself welding machine
