Electrical connection blocks: types of terminal blocks for wires

Those who repair the wiring at home on their own have more than once faced such a problem as connecting wires. Today, there are many methods for this, from the familiar old-fashioned way of twisting to modern electrical connector blocks. Regardless of the type of work - repairing the network or connecting new elements (socket, switch, etc.) - the connection must be reliable, because the safety of the home depends on it.

Ways to connect wires

There are many methods for connecting conductors. The most basic:

• mechanical twisting;
• soldering switching;
• using terminal blocks to connect conductors.

Absolutely any connection must meet a number of requirements that ensure its strength and safety. Some of them:

• mechanical strength;
• stable properties throughout the entire period of service;
• accessible location so that you can get to them for integrity checks and repairs;
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• the electrical resistance should be no more than 1.2 times the resistance value of the entire conductor.

The method of twisting wires is no longer provided for by the rules for the design of electrical installations, but it is still widely used in practice, especially in old houses. Now this method has been replaced by a connection using insulating clamps, which are presented in the form of plastic caps with a steel spring inside. Such a cap must be screwed onto a bundle of wires, forming a strong contact between them. This connection method is used for wires of the same material.

Soldering or welding is a very time-consuming process that requires sufficient qualifications of the foreman and special equipment. This method is often used when installing low-current electrical systems. In addition, the method refers to one-piece connections, is used for homogeneous materials.

The connection terminals avoid direct contact of different materials with each other, such as aluminum and copper. Contact of these materials can cause electrical corrosion, which will rapidly oxidize the compound.

Varieties of terminal blocks

Often, wire connection terminals are made of brass. Basically, a standard assembly consists of two pieces, but there are types with a large number. More expensive clamp options are filled with a special gel that prevents corrosion of the wires being connected. These devices differ in the diameter of the conductors, the permissible voltage and current. Today there are 3 types of electrical pads:

• knife;
• screw;
• spring.

Legrand Terminals

This is a kind of screw terminals for electrical wires of various diameters and materials. It should be noted that this type of terminal is not used to connect stranded conductors. The exception is conductors, which are crimped with a special brass tip. It is undesirable to switch aluminum wires with screw clamps. This is due to the low strength of the latter, because it is easy to push aluminum with a clamping screw until the metal structure is damaged.

A well-known manufacturer of screw connection terminals is Legrand. The fixtures are made of brass and then coated with a layer of nickel. Thanks to this, a reliable contact of the connection and high current carrying properties are achieved. Polypropylene is used as an insulating material, with which you can work at temperatures from -20 to +100 degrees. In addition, the material is resistant to open fire.

The popularity of Legrand connection systems is due to a number of characteristics that distinguish the terminals of this company from others. Key Features:

• high-strength connections;
• wide size range;
• the ability to work not only with low-current, but also with power circuits;
• a variety of colors that allow you to differentiate between wires for different purposes;
• a multistage testing system for finished products, which ensures compliance with all the necessary parameters.

The reliability and durability of the wire terminal can only be ensured with proper operation and installation.. The main advice of specialists when installing an electrical block:

• copper and aluminum wires must not touch inside the terminal;
• when making a connection using the Legrand system, mechanical stresses must be avoided, which can cause weakening of the contact;
• it is necessary to inspect the wires annually and tighten the screws to the desired voltage.

Before starting the fastening, you need to strip the insulating winding of the wire to a length that is half the size of the metal bus. Then, using a screwdriver, unscrew the clamping screw and insert the wire into the hole in the terminal. After that, tighten the clamping device with force to ensure reliable contact of the wire with the bus.

The company produces terminals in blocks of 12 pieces. They are able to withstand a voltage of 380 volts. These parameters depend on the wire size. The required amount can be easily separated from the general block with a knife.

Self-clamping devices

Wago produces connection types that do not need to be serviced annually like the previous version. The spring terminals without screws can be used to connect wires of different diameters. Such compounds have advantages over other species. Some of them:

• resistant to vibrations;
• the spring gives constant pressure to the wires, compensating for their deformation and providing continuous electrical resistance;
• easy installation that does not require special tools;
• the possibility of reusable connections without damaging the conductors.

Wago wire terminal blocks are made of tinned copper. Some types are filled with anti-corrosion grease.

The wire is clamped by a flat spring made of steel and plated with a chromium-nickel alloy. The insulating body is made of polycarbonate. This material has a wide temperature range, chemical resistance to weathering and corrosive materials. There are several design options:

• Push Wire - this type is used for permanent connections. A stiff spring prevents the wire from being pulled out without damaging it.
• Cage Clamps are used for reusable connections. Even very flexible conductors can be switched with it.

Before installing the electrical block, you need to strip the insulation winding of the conductor by 10-13 mm. Then use pliers to install the conductor into the terminal block. After carrying out the manipulation, visually check the depth of the wire installation.

Knife attachments

The connection of conductors with knife terminal blocks is used when the standards provide for the installation of a chain using an unbreakable conductive core. Often, such requirements apply to the earthing circuit.

Installation of such a switching system is carried out without stripping the conductors from the insulating winding. To do this, you need to insert the wires into the device and crimp them. Blade contacts cut through the insulating winding to ensure reliable contact. Connecting pads of this type are produced by Legrand, Klemsan. They are rated for 220 V. The maximum current varies depending on the cross-section of the conductors.

Experienced Electrician Tips

A good connection contact depends not only on the quality of the terminal blocks, but also on the preparatory steps. Some of them:

• You need to strip the wires with special tools. This is necessary in order not to damage the conductive core.
• It is imperative to remove oxide films from the surface of the conductors.
• To crimp stranded conductors, it is necessary to select the sleeve as accurately as possible.
• It is necessary to lead the conductor into the terminal block as deep as possible, almost before the beginning of the insulating winding.
• Using the method of pulling the conductor, you need to check the strength of the commutation.
• It is necessary to have a supply of wire in order to exclude mechanical stress on the terminals.
• In the junction box, the connections should be as far apart as possible. This is necessary in order to minimize the chance of a short circuit due to excessive heat.

Connecting wires is one of the simplest operations during electrical installation. It should be noted that the full functioning of the network depends on the quality of the procedure. A reliable connection can provide stable network characteristics that affect the uninterrupted operation of electrical appliances.