Methods for connecting wires in a junction box

There are many reasons for reworking old wires in home electrical systems. In particular, this concerns the reconstruction of old housing stock. Aluminum wiring with two cores is susceptible to corrosion and disintegration. A characteristic reason for this condition is the very poor insulation of many Soviet cables. Chemically, aluminum is more active than copper (the main material of pure cables). But this is in its purest form. When exposed to air, aluminum becomes coated with a strong oxide film and, in theory, should be more durable. But when the insulation shell crumbles or water flows into it while the wire is not energized, the wires are destroyed. The second factor is fire hazard. In some old houses, the insulation is made... from ordinary fabric. Which, of course, has decayed over the decades. The modern polymer sheath of the cables is also much better than the Soviet cambric worn out over decades.

Ordinary twisting of two wires

The abundance of new joining methods does not at all replace conventional twisting. In conditions of extreme repair, this is almost the only correct way out.The simplest curling of two wires, subject to an approximate estimate of the current strength (do not place a thin wire on a strong current), almost always works. But it is prohibited to combine copper with aluminum. They have relatively similar resistance values, but the copper is still less - and this creates an excellent thermocouple. The melting point of aluminum is slightly above six hundred degrees, so such twisting is a priori a fire hazard.
Pros: anyone can do it. There would be wires and hands.
Minuses: twisting is not airtight. Over time, the contact weakens, the resistance increases due to poor contact, the structure begins to heat up... and then everything is as in the case of twisting copper with aluminum. That is why this method is prohibited according to the rules of the PUE.

Stranding with soldering

An attempt to solve the problem of weak contact under ordinary twisting conditions. Actually, mechanical twisting is performed, and then you need to solder the contact point. You need a standard soldering iron, solder and flux. Solder - both ordinary tin-lead and newer variations. Flux can also be traditional rosin or new synthetic resins. The method works for a very long time and is therefore beneficial for capital docking for many years.
Minuses: all the delights of the “tin plague” or oxidized lead (depending on what was more in the solder). Soldering helps, of course, but more reliable methods of insulation are better. Boxes with separated wiring are most often shoved under the ceiling, which is why problems with soldering while hanging with your head thrown back are common. The problem of combining copper with aluminum is also not solved at all.

Welding wires

A new and popular method that is increasingly preferred by installers.A compact inverter and electrodes are taken, after which the ends of the formed twist are grabbed. Fast, practical, no fuss with solder, monolithic.
Pros: Reliability. With a properly homogeneous seam, the conductivity is simply excellent.
Minuses: Almost not. It is guaranteed that you will need a welder's qualification; whether this is considered a minus is an individual matter. In general, the requirements for welding qualifications are much greater than for simple electrical work.

Terminal blocks

Terminals are a fairly convenient and aesthetic type of connection. Simple assembly of the unit will not require much effort and time.
Pros: Simple, fast, without unnecessary stress. You can connect wires from different metals.
Minuses: To connect a stranded wire, you will first need to crimp it into a special tip. Do not connect more than two wires. It is necessary to periodically check the connecting unit.

Wago connection

Vago is a flat plastic box with an all-in-one concept. We strip the wire as if twisting it, insert it into the latch clip - ready. Suitable for a combination of any number of wires; there are many varieties for different current strengths and number of contacts. Ideal for quick electrical installation.
Pros: perfect sealing. Finally, you can connect copper to aluminum, you just need to follow the markings on the connectors. It is also possible to contact wires of different diameters, which is a plus in installing a “mixed” fleet of wires.
Minuses: Vago is expensive. It is very expensive. The Vago boxes do not change with anything, except for the same boxes, which cannot be assembled “on the knee” a priori.Therefore, this connection method is used either when you have a very good budget for electrical equipment, or when you need to connect wires going to expensive electrical equipment.

Bolted connection

Full compliance with the original name. A bolt, nut and three washers provide a strong connection between two different wires. Selecting a bolt from the appropriate material makes the joint resistant to electrical fluctuations. The main problem in this case is the dimensions. A lot of things are used as a distribution box. From store boxes to cans of instant Nescafe or tooth powder. But their fundamental property is the same - a bolted connection does not fit there. Or it will fit, but then it will cling to adjacent wiring and short-circuit. Therefore, it is better not to use this solution at all in a house where the distribution box has to be hidden.

Crimping

Performed with a special device. Another type of almost ideal, but very labor-intensive options for connecting wires. However, this is more than compensated for by the highest insulating abilities. Crimping is relatively inexpensive, the main part of the payment is the work of a specialist.
The above described wiring connection methods are selected in full accordance with the repair or construction strategy. In the ideal case, of course, it’s better to put everything into a crimping machine or Wago, but in fact it usually turns out that that kind of money is not budgeted for electrical peripherals. In urgent circumstances, you can use any type of connection, observing safety precautions and efficiently laying electrical networks. All “temporary solutions” must be immediately converted to capital ones at the first opportunity.This will significantly improve fire safety at the facility, as well as improve the quality of electricity transmission with a reduction in current losses, which can result in significant material savings.