Wire Terminal Blocks: An Overview of Reliable Options

Making connections with a conductor with such devices is not only convenient, but also safe

Today it is difficult to imagine the work of an electrician without the use of mounting accessories, namely, various terminal blocks. With the development of technology, new requirements are being established for safety and parameters of electrical networks in various premises, new requirements are being issued and standards are being established that have already banned the use of twists that were irreplaceable some 20-30 years ago.

As you might have guessed, today we will be talking about modern terminal blocks for wires - let’s tell you how remarkable it is, considering long-known and innovative models.

Types of individual terminals

It looks like a prefabricated terminal block for several cores, and inside it separate clamps are huddled

Let's go straight to the main point. To begin with, all the terminals can be divided into two types: electrical and electrical.

The difference between them is small, and lies in the maximum current load, so when choosing an option for a specific connection, always pay attention to this. In the rest, the models will differ from each other in their shape and way of fixing the cables, which determines the convenience of working with one or another device.

In the first part of the article, we will list the simplest versions of individual terminals, mostly related to electrical engineering.

Interesting to know! In addition to terminal connections, electricians use many other ways to connect wires, for example, soldering or welding, but these terminals are considered to be the fastest and most convenient to install.

Scabbard Terminals

Such terminals usually have two male and female connectors.

This type of terminal can be considered the most common. Probably everyone who saw them at least once inside some iron or under the hood of a car saw them. It is considered electrotechnical, since it is not intended for connections in power electrical circuits, that is, in an apartment or electrical panels you will not meet it.

• It is allowed to install such a solution on wires, mainly stranded, with a cross section of 0.26 to 6 millimeters.
• This is done simply - the end of the wire stripped of insulation is inserted into the crimping shank, after which its blades are pressed tightly against the center with the help of pliers, thus ensuring a reliable connection.
• Such terminals for the wire have counterparts, conventionally they are called "fathers and mothers." After installing each such part on the corresponding ends of the wire, they are inserted into each other. In finished products, “dad” is usually firmly soldered to some part, such as a relay, so you only need the “mother”, which is shown in the photo above.
• Two types of these terminals can be purchased: with and without insulation. The color of insulation is different and usually indicates the power of the product. The second option is more convenient to use when connecting individual wires, and then close the connection with electrical tape or heat shrink.

Ring terminals

Another common terminal variant

Here are the terminals used for screw connections of conductors. This option can also be divided into two groups that are non-insulated.

• The first type includes closed-ring models. To connect it, you need to completely disassemble the bolt connection, and after putting on the ends to be connected, tighten everything again.

Horn terminal

• The second type is a model with a broken contour, a fork or carob type, so to speak. Similar options can be used on unassembled bolted connections - just loosen the screed a little to make room for contact.

It is worth noting that both versions are widely used in electrical engineering. They can be found in the same cars or, for example, in various acoustic Hi-Fi systems.

However, the first type, nevertheless, is whiter than the common one, due to better technical characteristics. They can be used with wires of different cross sections: from 0.25 to 16.8 millimeters - whereas the fork type is designed for a much smaller range - from 0.25 to 4.6 millimeters.

Male terminals

Male terminal

In fact, it also relates to the knife type of connection of wires, but unlike the ones considered earlier, it has a completely dissimilar form of connectors. The terminals are completely isolated and have two mating connectors: a plug and a socket. Connection with wire conductors is also carried out through a crimp shank.

Similar tips can already be applied in electric chains. They are very convenient to use in combination with screw terminal blocks, which we will discuss below. This combination is used if the connected wires are stranded.

Coupling terminals

Coupling connection

This type of terminal is intended for single-core wires, which means that it can be used already in powerful electrical circuits. A connection similar to that shown in the picture above can withstand significant current loads. Terminals are available in various configurations.

Such devices are used together with wires with a cross section of 0.25 millimeters to the largest power cables. The conductor is fixed by power crimping of the cores with screws that complete the body of the product.

Terminal Block Options

Everything that we examined above is certainly interesting, but not applicable in terms of connecting wires in intra-house electrical networks. For these purposes, ready-made terminal blocks are used, which we will consider in the second part of the article. These devices can be screw or spring - the last option we have not yet considered, but be sure to correct along the way.

Advice! Sometimes it becomes necessary to connect an aluminum wire with a copper wire, but this cannot be done directly, since these metals form a galvanic pair with each other, and metal oxides can decompose into charged ions, and electrolysis begins, as a result of which they break down. Terminal connections made from a third metal, such as brass, will help out.

All terminal blocks are usually made of brass. Inside the housing are assemblies from several terminals, which allows you to simultaneously connect several current-carrying conductors.

There are models in which a special gel is pumped that prevents corrosion of metals. As in the case of individual terminals, the models presented below will differ in the cross-section of the conductors and the maximum tolerated load.

Legrand - terminal blocks that conquered the world

Screw terminal blocks

Screw terminals are very widespread in the world. In fact, the product consists of parallel couplings, separated by a dielectric body.

Such devices are sold with plates that can be divided with a knife into parts with the required number of joints. Instructions for their use is no different from the same couplings, but the presence of insulation speeds up and simplifies the work.

Aluminum wire

Interesting to know! In terminals of this type it is not recommended to put on aluminum wires, in view of their low mechanical strength - by transferring the core, we create a point with increased resistance, which means local overheating.

• The products of the French company Legrand are very popular in the world. Their terminal blocks are not just made of brass - the metal is additionally coated with a layer of nickel, which allows to increase the conductive properties and make the contact connection more reliable.
• Polypropylene is used as an insulating material, which is able to maintain its technical characteristics in a rather wide temperature range - from -25 to +100 degrees Celsius.
• The material is quite resistant to the effects of open fire, although not very long time, but still.

Surely you have met many similar connectors from different manufacturers, but products from France are not in vain trusted by consumers:

Wire Connection Example

• Very high mechanical bond strength;
• Wide range, up to options for wire cross-section of 25 mm2;
• Switching by such terminal blocks can be carried out both in low-current circuits inside living rooms and in industrial premises where the corresponding equipment is connected;
• Isolation of the terminal blocks is done in different colors, which allows you to conveniently navigate the purpose and capabilities of individual models;
• All products are certified and meet all the requirements and standards of the Russian Federation and the European Union.

We here, in fact, worked a little on advertising, but this is not entirely true - the conversation was about the most famous world manufacturer. At the same time, products from other companies that are not inferior in quality to the French are presented on the market.

Among such manufacturers will be both domestic producers, and Turkish, and other European, therefore, if you wish, ask the seller for a quality certificate to make sure of the quality of the goods being purchased.

Packing with terminal blocks

However, despite all the obvious advantages of such connectors, their reliability will also depend on the correct installation.

Here are some tips:

• If copper and aluminum wires are connected, then it is necessary to exclude their contact inside the terminal, due to the reasons stated above;
• If you use such connectors inside the junction box, then first of all you need to take care of the absence of mechanical stresses (that is, bring the wires to a sufficient length, and carefully lay them), otherwise situations with weakening of the contact are possible, which is fraught with a deterioration in its quality;
• If the mechanical stress of the wires could not be eliminated, then periodically (once a year) it is recommended to audit the connection and tighten the screws.

All Legrand terminal blocks of this type are capable of operating at 380 volts and can withstand loads of up to 101 amperes.

Wago terminals

German quality

The disadvantage of screw connections, as you understand, is the need for periodic revision of the connection. The following hero of our review does not have this drawback.

Here is a spring terminal block from the German company Wago. Such designs provide maintenance-free high-quality connection of wires of different sections.

These devices are characterized by the following features:

• The joint is very resistant to vibrations;
• The spring exerts constant pressure on the cores - this feature is able to compensate for the deformation of the conductors;
• Do-it-yourself installation is extremely simple , and only what is required from the tool that will help remove the insulation from the wire;
• The design of the terminals provides easy access for the measuring tool , which is convenient for repairs.

The structure of the terminal "Wago"

• The core is fixed due to a flat spring , which has a very ornate shape.
• The spring itself is made of steel and coated with an alloy of chromium and nickel.
• Core insulation is carried out through a polycarbonate or polyamide housing . Both materials have a wide temperature operating range, are chemically resistant to weathering and various substances.

A contact group can be performed in various ways, among which the most common ones can be identified - PUSH WIRE and CAGE CLAMP:

Schematic structure of the terminal block

1. PUSH WIRE - the connection is designed in such a way that it is applicable only to conductors of sufficient stiffness, mainly single-core. To fix, you need to strip the wire 10-15 mm and just push the core into the desired hole on the terminal block. Although the connection is considered to be one-piece, it is simple to remove the wire - it is enough to simultaneously rotate it around the axis while pulling, which is not always possible to do.

Collapsible connection

1. CAGE CLAMP - an option used for detachable switching. The spring structure of such a terminal block is unique and patented by the company. They are suitable not only for working with single-core, but also stranded wires. Moreover, their cross section can reach 4 mm2. To fix the wire in such a terminal strip, it needs to be stripped 10-15 mm, inserted into the hole and lower the clamp lever. In this case, the compression force of the core will depend entirely on its cross section - this is a feature of the spring design.

Among the shortcomings of such compounds can be distinguished: a higher price, but it is not surprising, because quality always costs money, and the larger space occupied by the terminals.

Vago terminal blocks are available for connecting from 2 to 8 conductors, designed for different characteristics of wires. The operating voltage is 220 volts, and the maximum possible load is 32 Amperes, which at home meets all requirements - for example, almost all sockets are designed for 16 Amperes.

Conclusion

This concludes our review. As you can see, wires, terminals, reliable connections, mechanical strength - everything that does not leave the head of a professional electrician should be applied and taken into account by amateurs in the field of electrical engineering. Of course, in the material we did not name all the terminal options, since we did not want to tighten it much - the video that we picked up will complement the article.