Categories: Featured Articles » Electrician Secrets
Number of views: 72784
Comments on the article: 22

Why welding is always better than other wire connection methods

 

Why welding is always better than other wire connection methodsAccording to the Rules of Electrical Installations (p. 2.1.21): connection, branching and termination of wires and cables should be carried out using crimpingwelding, soldering or clamping (screw, bolt, etc.) in accordance with applicable instructions.

No matter how convenient (for lazy people) methods of connecting wires, they did not come up with, none of them can be compared with welding in terms of durability and conductivity of the contact. Even soldering is destroyed over time: there is a third, more fusible and loose metal (solder), at the boundary of different alloys there always exists transition resistancedamaging chemical reactions and so on are possible.

The duration and complexity of high-quality soldering is not inferior to welding: thorough cleaning of the ends, the use of fluxes, deep heating of the whole twisting (whereas wire welding usually done in a couple of seconds).

twist weldingVarious crimps and terminal blocks do not stand any comparison at all. Copper - the main material of conductors - metal is completely inelastic, ductile. It has the ability to "leak" from under the load, even the Grover washers do not help.

In enough deep spring self-locking terminal blocksas a rule, the area of ​​the effectively contacting surface is too small. At high currents, this leads to heating on the release of these same springs: they lose their elasticity.

After welding, the concept of “contact” disappears altogether: the electric current does not pass through some (even very tightly touching) boundaries of the conductors, but flows through a monolithic metal of the same type. Of course, the resistance of such compounds turns out to be record low, and, accordingly, heat generation practically does not occur (due to the thickening during reflow and the absence of dense insulation, the temperature of the connection at maximum current can even be lower than that of the lead wires).

Welding is carried out at the ends of previously twisted conductors with a carbon electrode using apparatuses with a power of about 500 W (for a twist section up to 25 mm2). Due to the relatively low currents and low (compared with steel) melting temperature, the process occurs without a large blinding arc, without deep heating of materials and spatter of metal. Of course, this does not negate goggles, heat-resistant linings, etc., but all safety measures can be greatly simplified in comparison with power welding.

Wire welding machine

Coil welding machine

To prevent the oxidation of conductors, a special flux “VAMI” or an ordinary drill is used. It is most convenient to lower the twisted conductors from above into the hole with a flux done in the corner. But some craftsmen perfectly melt the twist with a sharp electrode "on weight".

If after cooling and removing the flux such a compound is varnished and then insulated with PVC tape or a special cap, it will be almost eternal.

See also at bgv.electricianexp.com:

  • Connection by welding aluminum wires
  • Why wire twisting is prohibited
  • Methods of connection, termination and branching of wires and cable cores. Ray ...
  • Wiring methods: from twists to soldering
  • Welding wire connection

  •  
     
    Comments:

    # 1 wrote: Alexei | [quote]

     
     

    I agree that WELDING is the most reliable way to connect wires. But !!, WAGO spring terminal blocks, if you believe the information in the catalog, have heaps of all kinds of certificates for the quality of their products in different countries and in different energy sectors .... this makes you think about the quality of this type of connection. ps I do not advertise wago))), until recently, I myself thought that it was better to twist, there was no connection (apart from welding, of course)))

     
    Comments:

    # 2 wrote: Vitaliy | [quote]

     
     

    bulky and hemorrhoid

     
    Comments:

    # 3 wrote: | [quote]

     
     

    I completely agree. And with what varnish to cover the twist?

     
    Comments:

    # 4 wrote: | [quote]

     
     

    And in facilities where there is no electricity? Press tongs (mechanical, hydraulic) and copper sleeves = "cold welding" !!! After all, the compression force is 8tn or more. Monolith is not worse than welding.

     
    Comments:

    # 5 wrote: | [quote]

     
     

    We do not need eternal contacts - we will remain without work.
    For Victor - any nitro-varnish, as it is quick-drying, even nitro-paint, with a zapon varnish, but do you need it?
    Sometimes I cook wires with an inverter, in especially critical places (high humidity, high power)

     
    Comments:

    # 6 wrote: | [quote]

     
     

    Thank you Tell me how to cook with an inverter, if it’s not difficult for me, I don't know the power lowering by 12 V, but more than 10 mm 2 it is difficult to cook for a long time.

     
    Comments:

    # 7 wrote: | [quote]

     
     

    I have a tr-r converted from the school LATR to a secondary 14 volts, the cross section of the secondary winding is 25 sq.mm. Brews almost any wire. Coal rod with a diameter of 20 mm. It works for three years without any problems. Heavy only

     
    Comments:

    # 8 wrote: Sergei | [quote]

     
     

    Of course it’s easier, faster and better to cook twisting !!!!!!!!!!! Very fast!!!! soldering does not compare in any way, except in an industrial crucible, but trance is much simpler. With all sorts of cogs and springs there is nothing to compare))))))) It is welded easily and on weight, it was described in a textbook for technical schools of the years 60 - 70, recently found))))

     
    Comments:

    # 9 wrote: Andrew | [quote]

     
     

    All twists and crimping with welding, even nothing to compare. The most convenient, fast and reliable wire connection.

     
    Comments:

    # 10 wrote: | [quote]

     
     

    Welding, and where there is no electricity, a gas burner from a small spray can. Welding drives, I cook in 24V transom through power diodes 50A, welding current about 30A, electrode - copper-carbon brushes from the Volga starter cost a penny. If necessary, I disassemble the welding in such a way - I bite off the ball, bring another wire and weld again, it will not work to weld after welding, and vice versa.

     
    Comments:

    # 11 wrote: Alexei | [quote]

     
     

    The article reminded me of a slightly redone joke:

    A kindergarten teacher comes to complain to the ZhEkvoyenny part that her pupils began to swear after fixing electric wiring by electricians of this ZhEK.

    The boss calls subordinates and requires explanation.

    One of the electricians:

    Comrade boss, we fixed the electrical wiring, I held the stairs, and Ivan welded the lighting wires, and suddenly the molten copper began to drip onto my head, so I told him: “Ivan, shame on you, don’t you see that the molten copper is dripping right on your comrade’s head? I ask you to stop immediately! ”

    This is the question of how you will cook the joints on the ceiling, or in some uncomfortable conditions. What is the supply of wire you need to not float the junction box? ) In addition, welded copper and wire rod are two very big differences, it is not necessary to say that a monolithic wire is obtained, this is not true.

    For myself, I definitely chose crimping - quickly, conveniently, reliably. In fact, “cold welding” since the conductors at the contact point are compressed so much that after some time the metal will diffuse. Without the formation of carbon deposits, oxides and other defects.

     
    Comments:

    # 12 wrote: | [quote]

     
     

    Alexei, did it ever occur to you that every thing, as well as every method of work, has its own application? For example, the use of terminal blocks greatly simplifies and speeds up the work, but they can only be used in relatively low-current circuits. But when mounting the junction boxes, there is no better welding method. If there is no welding, then for copper wires - soldering. I have already had a welding machine for the third year, and before it was exclusively soldering. How many apartments and how many mansions were remade - the very first ones have probably been standing for more than 20 years - and not a single gripe.Pressure testing also has its own scope. The main application is for the installation of large switchboards, pressure testing of cable lugs, etc. By the way, about the wire rod you mentioned. It is usually used (as an extreme option) with the grounding device, and even then, only in the absence of a strip. And I don’t remember something, so that someone somewhere with something rolled out a wire rod. In the case of wire rod, it is simply corny cooked by electric welding, and at the end, a bolt is welded onto which a tip is pressed on the wire and tightened with a nut. Well, and, of course, regarding the mutual diffusion of metals, you have clearly gone too far. To obtain diffusion, the pressure must be at least an order of magnitude higher (or even more). As for the concept of "cold welding" - this is just a beautiful metaphor, and nothing more. For all your laudatory ode to pressure testing, the latter, alas, has such a parameter as the contact transition resistance. And, being in adverse conditions, this transition resistance tends to increase. And given that very serious currents flow through the cables, at substations, sometimes, you have to re-trim the cable lugs.

     
    Comments:

    # 13 wrote: | [quote]

     
     

    It was hard to get past this article. almost everything is right! But just about everything:
    first: The most reliable connection should probably be considered spring-loaded, in them the entire life of the connection is drawn by a special steel plate, which eliminates contact failure (an example of this Wago - patented German technology! but the quality of these terminals in Russia leaves much to be desired, therefore their use should be limited by express connection and in cases when the rated currents are much lower than the rated ones. By the way, the connection described in the article using self-insulating clamps (PPE) also applies to spring connections;
    in second place you should put the connection by crimping, but the procedure is quite time-consuming and requires the presence of sleeves and special equipment (special pliers);
    on the third place I would put the wire connection by welding and soldering. A very good connection method, however, during welding, there is some “burnout” of the wires just below the place of welding itself and, as a result, a decrease in the diameter of the wire, so that the contact will occur all due to the same twist and at high currents only a correctly selected automatic protection device will save;
    Well and further on the list.

     
    Comments:

    # 14 wrote: | [quote]

     
     

    I combine crimping and welding - wire sleeve, leaving a 2 mm outlet, and then I weld the end of the sleeve with wires into a single unit (ball). This connection is really more reliable than the wiring itself.

     
    Comments:

    # 15 wrote: | [quote]

     
     

    The more I read the comments of electricians - the more they look like electricians. There are of course the right options, but without explanation. The most correct in my opinion was Gennady No. 13 who commented. BUT only when considering the connection of wires in a WIRING box. The thing is that everyone either forgot or never knew (most likely) the properties of the electric current. One of the main properties of electric current is that it tries to flow along the shortest path (the same property, by the way, did not allow the development of the so-called "English" ring wiring system ... but about it like a thread another time .. .a need to know this system, in cottages and apartments the very thing). What is the result of this property? Nothing special, except that your favorite twist welding makes no sense in terms of electrical conductivity. The current simply does not reach your welding. The highest current density will be exactly where the insulation ends, and where the place of welding is, its value will be meager. And since you created an integral connection at the end of the twist, then where will be the greatest susceptibility to thermal deformation? That's right, in the twist body, just in the zone where the isolation ends. Continue to think for yourself.And the connection will not fail until it works in critical modes (this is for those that have been working for 20 years without complaints ... my father won’t twisted aluminum at the dacha 35 years ago and wrapped it with some kind of electrical tape, and it’s working, it works .. the truth is under my control .... but I do not replace, because it is interesting how much it will work if not overloaded). Welding is good when you overlap the wires, then this is really the best connection, and crimp in second place ... let's leave the solder for multi-conductor conductors with a cross-section of up to 1 mm.sq. But when you use twisting, the best tool is not welding, but PPE, since it makes it possible to twist the wires at the same level of stripping the insulation and constantly spring the contact along the entire length of the bare core (only please do not first twist and then put on PPE on it is just a mockery, because One of the indicators of reliable contact is just the twisting of the wires when wrapping the PPE). And finally, WAGO ... long-suffering .... but .. the best for wires of 1.5 and 2.5 mm.kv. Namely, these wires account for 99% of all soldering and mounting boxes. Cables of a larger cross section usually go straight from the shield to the consumers (well, if designed by a competent person) or branch using special junction boxes with screw pads.

    yes ... WAGO is WAGO and not iEK, TDM Elektric and similar terminal blocks .... if the progenitor of these terminal blocks is the most expensive .... that means in its competitors for 1/3 of the price well, clearly something is wrong .. ... USE ONLY ORIGINAL TERMINALS ..... All customer pays one)))))

     
    Comments:

    # 16 wrote: | [quote]

     
     

    Yes, I completely agree with the last comment. Everything is written quite accurately, but I also want to add that the connection by welding, T-shirt, and other types of non-detachable connections in household electrical installations DO NOT PLACE.
    Reason 1: let's say a short circuit has occurred in one of the cables; we need to find it so that we will bite this connection. And after two such or three times what is left of the ends in the box is to change anything all the cables.
    Reason 2 the owner wanted to add a socket or switch to himself; in the same way, the connection must be bit off and then similar to the first case.
    Reason 3 there are not so large currents flowing to make non-detachable connections so that more than enough high-quality screw or self-locking terminals.
    So Dear colleagues, let's not complicate the life of ourselves and others, we are doing everything normal.

     
    Comments:

    # 17 wrote: Alexander | [quote]

     
     

    Judging by the kamenty, people still drive horse-drawn carts, but the car is not reliable! There speed WOW! Your twisting x..yutki protect circuit breakers! Unless of course you know how to properly select them. Or are you still using traffic jams? For the WAGO terminal block to melt, you must exceed the permissible current for the cable! Question: what do you care about the terminal block or the twist if there is no insulation on the wires?
    Rzhunimagu with kamentov)))

     
    Comments:

    # 18 wrote: Oleg | [quote]

     
     

    There are only three of the most reliable connection methods: welding, crimping, soldering. Soldering is not recommended for PUE. Welding is as easy as welding. But crimping is easier.

     
    Comments:

    # 19 wrote: Vladimir | [quote]

     
     

    I read everything .... and here’s what I can say .... the best reliable and fastest connection in electrical installation is ... UNIQUE ...--- welding ... the wire becomes cast .... subject to careful installation in a box ...

     
    Comments:

    # 20 wrote: Nikita | [quote]

     
     

    #15 I would correct you. The current does not go the shortest way, but the path of least resistance, so all your conversations about cooking are not entirely accurate. There will be no transition resistance at the welding site, but partially burnt wires (as they say, with a reduced conductor diameter because of this) are compensated by twisting to the cooking place. I do a twist of 5 centimeters and brew the tip.

     
    Comments:

    # 21 wrote: Dmitriy | [quote]

     
     

    Quote: Sergey
    The thing is that everyone either forgot or never knew (most likely) the properties of the electric current. One of the main properties of electric current is that it tries to flow along the shortest path

    After such a "statement" the rest of your words based on it, it makes no sense to take seriously. How the current behaves can be determined using Ohm's law and the rules of Kirghoff. Current will flow everywhere, both through the twist point and through the weld point, where there is more resistance, there is less current and vice versa. (10/01/2018)

     
    Comments:

    # 22 wrote: Petya | [quote]

     
     

    Sergei,

    The thing is that everyone either forgot or never knew (most likely) the properties of the electric current. One of the main properties of electric current is that it tries to flow along the shortest path


    You say it almost correctly, but you haven’t finished it up a bit. The current does not flow discretely along only one path, but is evenly distributed along all possible routes in proportion to their resistance. Therefore, your conclusions are fundamentally wrong. The current will be distributed throughout the contact zone of the wires and the welding spot will have the least resistance and the current will mainly flow there. But let's say at the point of contact through which the current was going, resistance suddenly increased. An automatic new current distribution will occur. Even if the whole twist is oxidized, the current will flow ONLY at the place of welding, since there the resistance does not increase. That is why welding is more reliable than simple twisting.