8 Options For High-quality Stranded Copper Wire Connection. How To Choose A Reliable Way

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-05-24 22:24

• Various twisting options
• Professional connection
• Soldering wires
• Welding method
• Crimping
• Threaded connection
• Self-clamping terminal block
• Screw terminals
• Insulating clamps (PPE)

In the process of installing electrical wiring, especially in residential premises, it is necessary to use wire and cable connection technologies. This process requires some skill and knowledge. After all, an incorrect connection can lead to irreversible processes. Disruption of the general power supply may occur, as well as fires. The fact is that a carelessly executed connection of stranded wires can lead to a fire, which in turn leads to a threat to the life and health of people. The requirements for the installation of wiring in residential buildings are spelled out in the Rules for Electrical Installations, in abbreviated form - PUE. PUE allows the use of electrical wiring in residential premises, made only with copper wires. The connection of stranded and solid wires is allowed only by crimping, welding, soldering or using crimps. In clamps, the connection is made mechanically, using screws or bolts and terminals.

Various twisting options

Unprofessional connection. This is a twisting of a stranded wire with a solid one. This type of connection is not provided for by the rules, and if such a connection of wires is detected by the admission committee, then the object will simply not be accepted into operation.

Twisting a stranded copper wire in a steamed box is used as an intermediate operation before soldering or welding the junction, and it is imperative to solder or make crimp connections.

However, twisting is still used and here you need to know how the correct twisting of stranded wires is performed. It is often used in emergency cases when it is not possible to professionally perform a connection, and the service life of such a connection will be short. And yet, twisting can be temporarily used only for open wiring, so that you can always inspect the connection.

Why can't the wires be twisted together? The fact is that during twisting, an unreliable contact is created. When the load currents pass through the twist, the twist heats up, and this increases the transition resistance at the junction. This in turn contributes to even more heating. Thus, the temperature at the junction rises to dangerous values, which can cause a fire. In addition, a breakdown in contact leads to the appearance of a spark in the place of twisting, which can also cause a fire. Therefore, in order to achieve good contact, it is recommended to twist wires with a cross section of up to 4 mm ². Details about the color coding of wires.

There are several types of twists. When twisting, it is necessary to achieve good electrical contact, as well as create mechanical tensile strength. Before proceeding with the connection of the wires, they should be prepared. Preparation of wires is carried out in the following sequence:

• insulation is removed from the wire at the junction. The insulation is removed so as not to damage the wire core. If an incision appears on the wire core, it may break at this point;
• the bare place of the wire is degreased. To do this, it is wiped with a rag dipped in acetone;
• to create a good contact, the degreased section of the wire is cleaned with sandpaper to a metallic sheen;
• after connection, the wire insulation must be restored. For this, an insulating tape or heat-shrinkable tube can be used.

In practice, several types of twists are used:

• simple parallel twist. This is the simplest and most common type of connection. With good parallel twisting at the junction, good contact quality can be achieved, but the mechanical tensile forces will be minimal. Such twisting can loosen in the event of vibration. To correctly perform such a twist, it is necessary that each wire twists around each other. In this case, there must be at least three turns;

  

  

• method of "winding". This method is used if it is necessary to branch off the wire from the main trunk. For this, the insulation of the wire is removed at the branch section, and the branch wire is connected to the bare place by winding;

• bandage twisting. This type of twisting is often used when connecting two or more solid wires. For bandage twisting, an additional conductor is used made of the same material as the wire cores. First, a simple parallel twist is performed, and then a bandage from an additional conductor is applied to this place. The bandage increases the mechanical tensile strength at the joint;

  

• connection of stranded and solid wires. This type is the most common and simple, at first a simple wrapping is performed, and then clamped;

other various connection options

In detail, about the methods for connecting single-core wires

Professional connection

Consider various options for a reliable connection according to technology: soldering, crimping, welding and terminal connection of wires. You will give up unreliable twisting when installing unsoldered boxes and other connections.

Soldering wires

The connection of copper stranded and solid wires by soldering is one of the reliable methods. This connection creates good electrical contact and the connection is mechanically resistant to breaking loads. This method can be used when: splicing two damaged wires, lengthening wires, moving outlets or switches. The wires connected in this way can be used in hidden wiring. If you insulate the junction well, then such a wire is not inferior to a solid section.

The technology for such a connection is as follows:

• preparation of wires is carried out in the same sequence as before starting twisting;
• cleaning to a metallic sheen of wire sections;
• solder coating of joints (tinning);
• wires are connected with one of the types of twisting;
• twisted wires are soldered with solder;
• the place of soldering is processed with emery cloth. There should be no burrs at the soldering point that can damage the insulation;
• the junction is carefully insulated.

The wires connected in this way can be placed under the plaster. For reliability, the joint should be placed in a PVC tube.

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Welding method

Welding belongs to the category of permanent connections. This type is the most reliable. It is with this method that the connection section acquires solidity. The contact resistance and mechanical strength of the connection section are no different from a solid wire. Welding is carried out both on direct and alternating current.

For professional welding of wires, various types of welding machines are used, but the most widely used are inverter current machines. These devices are mobile, they are easily carried on the shoulder of an electrician, they are small in size.

Inverter devices are distinguished by a wide range of operating current regulation. The welding arc is easily ignited even at low operating currents, and is stable during the entire welding period.

In addition to the welding machine for welding copper wires, it is also necessary to have carbon, copper-plated electrodes.

Welding technology consists of a few simple steps. First, the insulation is removed from the wire. Then, according to the technology described above, the wires are twisted. The twisted wires are straightened by trimming their ends. In order not to overheat the wires and their insulation, it is necessary to remove heat during the soldering process. For this, a special clamp is used, which is connected to one of the poles of the welding machine. Welding is carried out by touching the ends of the wires of the working electrode, which is held in a welding holder connected to the other pole of the welding machine.

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Crimping

When crimping, the wires are placed in special mounting sleeves, which are made of the same material as the wires. In this case, made of copper. Then the sleeves are compressed with a special tool. When the sleeve is compressed, the wires are deformed, Deforming, the wires are tightly compressed with each other. When pressed locally, the wires are deformed in such a way that their individual points penetrate into each other's body. Thus, a reliable electrical contact is created and the connection point becomes mechanically strong. Crimping is used to connect the wires that are placed in junction boxes and electrical cabinets.

To perform crimping, special assembly pliers are used. For connecting wires when installing wiring in residential premises, crimping pliers of the PK-16 model have gained wide popularity. To connect copper wires, connecting copper sleeves of the GM type are used. They are made of copper and are red in color.

So that the junction does not come into contact with oxygen, it is preserved with a special technical petroleum jelly. Thus, the junction is isolated from the harmful effects of the environment. The wires will not oxidize and the connection will last for a long time. The connection can still be sealed with a heat-shrinkable tube.

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Threaded connection

This type of connection, the connection of solid and stranded wires, belongs to the category of detachable connections. For this, special terminal blocks are used, consisting of both cases and devices built into them, designed for screw clamping of the wire. It is necessary for a reliable connection to communicate or tin the wire. The most widespread use was obtained when connecting end consumers. (lamps and chandeliers)

Self-clamping terminal block

It is used to connect wires with a cross section of not more than 2.5 mm ². With this type of terminal block, up to 8 wires can be connected simultaneously. They are used to connect wires in electrical cabinets. It is mainly used for lighting routing. Use more reliable connection options in the socket group under heavy loads.

Screw terminals

This type of terminal blocks is one of the most demanded devices. With their help, only copper wires are connected. Due to their small dimensions, they are used when connecting wires in junction boxes.

Insulating clamps (PPE)

These clamps are used to connect wires of small cross-sections up to 25 mm ². The clamp structure consists of a plastic body. A cone-shaped spring is located inside the housing. To connect the wires, they are first twisted into a bundle, and then a clamp is screwed onto it. The wires are connected by holding them with a spring. The junction does not require additional insulation, since the cap body is made of insulating material.