Wire connectors: the best types of connectors + what to look at when choosing a connector

Vasily Borutsky
Checked by a specialist: Vasily Borutsky
Author: Tatyana Zakharova
Last update: May 2019

The electrical network of a single house is a complex system of wires, electrical installations and a protective automatic group. The most vulnerable points are the switching points of two or more conductors.

The task of the electrician is to select and correctly install the wire connectors that will be most suitable for the characteristics, perform their function perfectly and, most importantly, ensure reliability and safety.

We will figure out what types of connectors are most often used in everyday life, what kind of switching devices are suitable for which work, what are the features of their installation. In addition, we will provide practical recommendations for choosing the appropriate type of connector.

Classifications and GOST requirements

Wire connectors are any devices that serve to close / open an electrical circuit. This can be wiring products - sockets, switches, as well as metal tires and plates, lugs, terminals and terminal blocks - blocks with several sockets.

We will focus on connectors in a narrower sense - on elements that create collapsible and non-collapsible connections and ensure their reliability and functionality - that is, on all kinds of terminals, terminal blocks and sleeves.

Crimping the wire with a sleeve
The simplest example of a lug for a stranded wire. The terminal is a metal sleeve-tube fixed on the end of the conductor with crimping pliers

Terminals are called as metal elements for the design of the ends of single and multicore wires, and small plates inside the connecting devices - sockets, terminal blocks, patch panels.

Wires are fixed by terminals
The terminals differ in material of manufacture, shape and size, but are similar in purpose - they provide mechanically strong switching of two or more wires, without electrical losses and installation difficulties

The classification of electrical connectors is presented in GOST 10434-82, where information is given on the division into classes (1, 2, 3) and into groups (A, B).Also, contact connections, according to standards, are divided into detachable and one-piece, requiring stabilization or working without it.

Some recommendations may be useful not only for professionals, but also for home masters who independently equip wiring.

For example, it talks about the most preferred methods of joining aluminum plates — by soldering or welding, and aluminum tips — by crimping or welding.

Popular types of connectors

Switching wires by soldering or welding in households is becoming less common. Special devices have come to replace that facilitate the installation process and shorten the time of work. Their main advantage is accessibility for lovers.

For example, to connect two conductors with a Vago terminal block, you do not need to know its design or principle of operation - it is important to correctly install it.

Consider the features of products that may be useful if necessary. wire connections without soldering during wiring or electrical repairs.

Cable type terminals

For quick detachable connections, cable terminals are installed on the conductors on one or both sides.

They participate in various electrical procedures:

  • when connecting inductive coils;
  • in power supplies, generators and starters;
  • in windings of transformers and motors, etc.

The material and number of cores does not matter: they are installed on single and multicore wires made of aluminum or copper. Moreover, the elements themselves are produced mostly from copper, nickel, brass or bronze.

Consider 4 types of terminals required for the assembly of electrical circuits.

Option # 1 - knife

On sale you can find a variety of brass and nickel tips, uninsulated and insulated. The simplest and cheaper - non-insulated products, their cost starts from 0.2 rubles. a piece.

Crimped knife terminals
Knife elements can be found if you disassemble an iron, heating device or other household appliance. They are part of the circuit and connect two or more conductors to each other

This type is not used to equip power wiring, for example, in assembly of electrical panels they are not involved. Most often, multi-stranded wires are crimped with knife tips, the cross section of which is no more than 6 mm².

The shell of insulated products varies in color, which depends on the rated power of the connection block or other terminal block.

Option # 2 - Ring

The shape of the elements is reflected in the name - they resemble a closed ring. Like the previous version, they are isolated and uninsulated. The flat part of the first is placed inside the polymer winding.

Ring connectors
The connection with the ring terminal is considered more reliable by increasing the area of ​​contact of the flat circle with the oncoming terminal. Strong fixing is provided with a bolt or screw clamp

The fixing screw is inserted into the “circle” of the terminal, the nut is screwed on the reverse side, after which the probability of the conductor slipping out of the connection is reduced to zero.

Production material - aluminum, nickel, copper, brass. Ring products are used not only in low-current, but also in powerful lines of force of large cross section, under a bolt of 27 mm or more. They are connected to the conductors by soldering, welding or crimping.

Option # 3 - Forklift

Switching of both power and secondary circuits is also carried out using fork tips, in the form of a plug with two rounded teeth. The terminals are fixed either on the devices or on the busbars with a screw connection.

Insulated fork terminal
This form, unlike the ring one, is convenient when the conductors often need to be reconnected or connected only temporarily with subsequent disconnection. To remove the conductor, you do not need to completely unscrew the screw, just loosen it slightly

However, the connection itself is no less reliable than the ring, the contact due to the twisted screw is quite tight. Terminals in the shape of a plug are suitable for wires with a cross section of up to 6 mm², the method of attachment is crimping.

Option # 4 - pin

Tips in the form of pins are used in detachable connections, which differ in marking: the plug is indicated by the letter "A", and the socket - "B". Suitable for conductors of various sizes, up to approximately 6.5 mm².

Different terminal blocks
The element itself consists of two parts: a metal open pin and an insulated part, to which a copper or aluminum conductor is attached

The color of the insulating shell is tied to the cross section: for example, for some manufacturers the polymer part of the terminals with a cross section of up to 2 mm² is blue, and with a large cross section - yellow.

Sleeves for pressure testing

Excellent contact between two or more conductors provides a crimping method, which is produced using metal sleeves of various diameters.

As a result of pressing operations with a special tool, the cores turn into a monolithic, but already inseparable connection.

Sectional pressure sleeve
The pressed sleeve cannot be removed to separate the conductors. If you cut it across, you can see how the veins form a single monolith

If separation of spliced ​​conductors is necessary, then mechanical cutting should be performed and the sleeve removed - it cannot be used again. On the one hand, one-time use and one-piece use are disadvantages.

Sleeves as connectors have some advantages:

  • they do not destroy the conductors, like the same screw clamps, but make the connection as strong as possible, not burnt;
  • maximally protect copper conductors from contact with moisture and air, that is, from oxidation;
  • create a reliable connection from a mechanical point of view - it cannot be accidentally broken.

For crimping, they use a special crimping tool - pincers, which are also called a crimper. In addition to it, they can come in handy stripping stripper and nippers for trimming.

The use of cartridges:

As a result, we obtain durable, well-conducting, one-piece connections that do not deform when heated and do not melt during power surges.

Connection by sleeves in the junction box
The power wires are often connected with a sleeve in precisely junction boxes, the approach to which will later be blocked by sheets of drywall or other cladding

The most reliable GM - copper sleeves without additional processing and GMF - tinned copper sleeves coated with an alloy of bismuth and tin. The second option is more reliable, since the protective layer protects against corrosion and oxidation.

Both types of sleeves are not suitable for connecting aluminum conductors. For this, special GA - aluminum sleeves. To connect copper and aluminum used Gam.

Insulated sleeves for connecting wires
The best of the existing ones are GSI - insulated products. When crimping, additional insulation is not required, it is only necessary to crimp

The size of the sleeve is selected depending on the total value of the conductors. The choice is large - for example, on the market are GMDs for wires with a cross section from 2.5 mm² to 300 mm².

Terminal Blocks - Switching Devices

The terminal blocks are not part of the wires, as are the terminals, but rather devices for switching.

They can connect different types of wires:

  • in isolation;
  • with insulation removed;
  • with installed terminals.

The species assortment is large, we dwell only on the most common, affordable and widely represented in stores.

Option # 1 - Screw Pads

Wiring accessories designed to connect paired conductors are called pads.

They are a dielectric strong plastic case, inside of which there are sockets with terminals and screw fasteners for conductors.

Screw connection
To ensure the switching of a pair of conductors, it is necessary to insert their ends into sockets located opposite each other, and fixation by screw method

Pads are sold in large blocks, which can be reduced if necessary. To do this, cut off the desired number of paired cells with a construction knife. For example, to connect three pairs of wires in a junction box, you will need a section with 3 pairs of sockets.

The disadvantage of using pads is that they do not provide a reliable connection. Over time, the screw mount becomes loose, as a result of which the connection weakens.

If copper can withstand this situation, then aluminum will overheat and spark. The way out is regular revision and tightening of screw fasteners.

Connection of solid conductors with a terminal block
Another minus of terminal boxes: they are used only for connecting conductors to one core. Stranded wires are deformed and broken during fixation, which leads to overheating

Product advantages: “fitting” in the number of connections, quick installation, only a screwdriver is required from the tools.

What to do if it is necessary to connect several stranded pairs, and only pads at hand? It is possible to carry out switching using connectors for wires - install on the ends of the terminals.

Crimped pin lugs suitable for diameter cells are ideal.

Option # 2 - Spring Terminal Blocks

Connectors with a spring mechanism clamp one or more conductors and hold them, without reducing the pressure density.

There are two types of "spring loaded":

  • disposableproviding one-piece connection;
  • reusablewhich can be disassembled if necessary.

The design of the product is simple: inside a polyamide or polycarbonate body that can withstand high temperatures, a steel spring fixed with a chromium-nickel alloy is fixed. The connection terminal is made of tinned copper.

Lever wagon terminal block
Dismantling the conductor from the reusable terminal block is carried out by pressing the lever located on the housing. It is used if it is again necessary to make switching.

One of the varieties of spring terminal blocks is designed specifically for installation under a DIN rail, that is, for the equipment of electrical panels and cabinets.

Terminal block
Spring connectors are often used in domestic conditions, for example, for connecting lighting circuits. They can be single or block, consisting of several terminal blocks

Product Advantages:

  • provide a reliable connection;
  • carry out the switching of conductors from different materials;
  • have low resistance;
  • do not require the use of a special tool;
  • reusable without loss of functionality.

The disadvantage of spring elements is the inability to maintain powerful power lines, only small currents are available.

Option # 3 - self-locking connectors

Expensive, but the most convenient to install switching devices. A pressure plate is enclosed inside the case, which is triggered if the conductor is inserted according to the instructions to the stop. The bare part of the core is pressed against the tinned tire.

Self-locking terminal block in box
The design is designed in such a way that over time, the connection does not weaken and does not lose its qualities. Strong manufacturing materials also contribute to this.

The disadvantage of most self-clamping devices is their one-time use. However, there are products with levers that can be used several times.

In the product line connectors Wago There are several varieties of self-clamping terminal blocks that have proven themselves from the best side.

In addition to the listed connectors for electrical wires use:

  • knife terminal blocks - suitable for switching conductors without stripping;
  • couplings - fasten by a screw method.

The latter version of the device is used less often.

How to choose the right connector?

When choosing the right type of connector, everything is important: the brand, the material of manufacture, the diameter of the switched conductors. Do not forget about the current load - even the most reliable terminal blocks have limitations.

Professional installers clearly know which connectors to use in a given situation, while amateurs can make a mistake and install the wrong connector. We will analyze cases that cause difficulties in choosing.

If you want to put the connected area in water, then it is better to make a soldering commutation, after which fill everything with hot glue and close it with heat shrink from above.

Conclusions and useful video on the topic

Briefing on the use of various types of connectors:

In detail about sleeves and crimping pincers:

Why are self-clamping terminal blocks good:

The right choice of terminals and connectors ensures safety without which any electrical network cannot exist.. If you have a tool, you can connect the wires yourself using the appropriate type of connector.

VAGO connectors are especially easy to install, however, subject to the switching instructions.

Have experience connecting wires? Or want to ask questions about the choice and use of connectors? Please comment on the publication and participate in the discussions. The feedback block is located below.

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Visitors Comments
  1. Wago is, of course, easy to use. It is also convenient that they can be repeatedly connected and disconnected. I made a friend lights on them on a summer terrace, so that you can shoot for the winter. But there are low-power LED lamps, I'm not worried about them. But a big load - a stove or a microwave, is scary to connect to Vago. The contact area is too small there, would not warm up.

  2. Zhenya

    Which connection is better to use for powerful equipment? They say that the usual twisting of wires does not work, why?

    • Expert
      Vasily Borutsky

      As I like to say, but it was not me who invented it, but I heard from my teacher: “Good twisting is better than bad soldering”. And this has been confirmed in practice more than once! But now there are so many different terminals that it is easy to connect wires from different materials and different sections. Without special terminals for connecting copper and aluminum wires, the usual nut, bolt and washer will help.

      If there is no experience in soldering, then the twisting will be more reliable, for an example I will attach a photo of a high-quality twist of wires. Plus an example of a terminal and twisting of copper and aluminum using improvised tools.

      Attached photos: