Terminal Blocks For Connecting Wires: Which Terminal Blocks Are Better And Why

Maintenance of electrical networks is inevitably accompanied for electricians by work with terminals. It is a kind of small mounting hardware, without the use of which it is difficult to do without when making connections between wires or with electrical equipment.

Time has eliminated obsolete terminals for connecting wires from practice, but steadily adds new developments - more perfect.

We will help you to understand the variety of electrical fittings. The article deals with the different types of terminal blocks and describes their application and mounting features.

The contents of the article:

  • Types of electrical connections by terminal clamp
    • Variant #1 -\"sheath\"
    • Variant #2 - ring
    • Variant #3 - pin
    • Variant #4  - coupling clamps
  • foreign products
    • Coupling #1 - Push Wire
    • Coupling #2 - universal power cage clamp
    • Coupling #3 - set cage clamp
    • Coupling #4 - cage clamp S
  • Twisted wire connectors
  • Conclusions and a helpful video on the subject

Types of electrical connections by terminal clamp

In examining all the terminals produced by industry for connecting wires, it is necessary at once to stipulate and divide the products into two kinds: electrical and electrotechnical.

In fact, the difference (in terms of current load) between the types is often small, but still it is there. This should be kept in mind when selecting electrical terminals for installation, repair or other activities.

Terminal blocks for connecting wires: which terminal blocks are better and why

Terminal connections are used everywhere in the electrical industry. It is one of those electrical components without which a quality installation of any plan is unthinkable

Faced with the need to select electrical terminals for wires, you should start with the simplest designs made at home - reliable, durable, tried and tested more than once.

There are the following types of \"clamps\":

  • knife;
  • ring;
  • pin;
  • muff.

Connections in electrical schemes can be made by different methods and terminals are only one of the choices. But this is the one which seems to be the simplest, most convenient and even economical in comparison with, for example, soldering, welding, including cold welding.

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Tools and appliances for electric installations

Fabrication of firm, protective connections

Healing the conductor tightly

Terminal clamps for lighting connection

Positioning of terminals in the appliance housing

Wiring terminal clamps

Pressing terminal block models

Complex connection terminal blocks

Variant #1  - \"sheaths\"

These are probably the most common design variants of the products. You can often find them in the electric circuits of many household appliances: irons, refrigerators, heating devices, etc.

But they are not designed for connecting the conductors of power wiring, for example in the electrical boards of an apartment.

Terminal blocks for connecting wires: which terminal blocks are better and why

A familiar to many electricians and widely used type of terminals, whose connection is done on the principle of a knife contact. It is sufficient to insert one part (papa) into another (mama)

Installation of this type of products is allowed on conductors (stranded) with a cross section of 0.26 - 6.0 mm by means of a power crimping method.

There are two types of products: insulated and non-insulated. The insulation is usually colored in different colors (red, blue, yellow) depending on the rated capacity of the terminal block. Products are used in pairs in a \"Pa-Ma\" arrangement.

Variant #2 - ring

Ring products are configured for screw mounting and are represented by two groups. Both groups are classified as non-insulated terminals.

The first group includes closed ring designs with a shank. The second group consists of forked-type designs with a broken ring contour, also with a shank. Both are widely used in electronic circuits.

Terminal blocks for connecting wires: which terminal blocks are better and why

Another \"ancient\" kind of element which creates an electrical connection between a conductor and some modular circuit element. These terminals may be used for connection of two wires, but in practice this is rare

Ring terminals of the first kind are produced in a wider range than the second kind. And the application possibilities are wider given the technical characteristics.

This type of electrical products is allowed to be mounted on electrical conductors of 0.25 - 16.8 mm cross-section. And the forked configuration of wire connection terminals is designed only for wire cross-sections of 0.25 to 4.6 mm.

Variant #3 - pin

This group of electrical wire connection terminals is made on the principle of a connector piece consisting of two separate elements, a plug and a socket.

The plug is marked with an \"A\" symbol, such as F2A. The socket is marked with a \"B\", e.g. F2B. Installation on conductors of 1.25 to 6.64 mm cross-section is supported. The main purpose of pin terminals is to provide a connection of electrical conductors.

Terminal blocks for connecting wires: which terminal blocks are better and why

One of the pin terminal block designs used generally in low current circuits. Designed to allow easy handling during assembly/disassembly

This group of mounting hardware refers to insulated products. The back of the terminals is covered with insulating material. Depending on the rated capacity of the terminal block for connecting wires, the insulator is painted correspondingly.

The insulators of electrical terminals for conductor cross-sections up to 2 mm are painted blue, the others (from 2 to 6.64 mm) are painted yellow.

Variant #4 -coupling clamps

Another type of connection fitting is the coupling clamp made in the form of a metal tube.

Terminal blocks for connecting wires: which terminal blocks are better and why

The so called coupling clamp. Available in different configurations including power crimping. The figure shows a terminal block capable of carrying high currents

Coupling sockets designed for mounting on electric conductors of 0.25 - 16.78 mm.

Coupling is achieved by power crimping of part of the tube or by screwing into threaded holes on the body of the socket. As a rule, crimp sockets are not used to connect solid wires.

Foreign made products

In recent years the market has been flooded with foreign made terminal blocks. One has to give the credit: technologically foreign designs look more perfect in comparison with domestic products. They are more convenient to work with - faster and easier to make connections.

But in terms of reliability of the connections made by the foreign product is not so unambiguous. In this respect, the domestic product often looks preferable. However, let's look at some examples.

WAGOWorthy electric terminals. The company's engineers have invented several attractive constructions, where a normal terminal is transformed into a useful connection interface: Push wire, Power cage clamp, Cage clamp.

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The leader in wiring products

Mounting of electrical Electrical connection

Transparent terminal blocks by Wago

The transparent terminal block series for assembly control

Flat spring connector

Flat Multiple wire clamping

connection of multi-metal conductors

Joint #1 - Push Wire

The Push Wiretechnology is based on the stiffness properties of the electric conductor, which results in a quite secure contact.

This type of terminal block is the most suitable for use with solid wire. Indeed, Push Wire provides a fast connection method without any compromise.

Terminal blocks for connecting wires: which terminal blocks are better and why

The product of a well-known German company is a modification called Push wire. Easy to use variation of single and group connector

Just peel a part of the wire (10-15 mm) and push the peeled end inside the terminal with a small effort. And to extract the conductor just as quickly, it is necessary to pull it out while turning it on its axis.

Two kinds of Push Wire connectors have been designed:

  1. A single conductor.
  2. A group of conductors.

The group connection configuration is designed to run with wires of lower rigidity than the single version. A slightly different mechanical clamp design is used here.

To access the wire entry holes, some force must be applied to the push button. There are also Push wire models without push button - for screwdriver push action.

Connector #2 - Universal Power cage clamp

This terminal block belongs to the category of universal designs. It is made for any type of electric wire with a cross section from 6 - 95 mm.

Formally Power cage clamp is a so called double cage with a spring press and a current carrying rail.

Terminal blocks for connecting wires: which terminal blocks are better and why

A universal terminal for the connection of different conductor cross sections. An engineering solution which assures a firm and tight contact. This kind of connection accessory is suitable for the assembly of lines with different wattages

The electrical conductors are connected to these terminals by means of a hexagonal key. The spring is pressed by turning the wrench, the wire end is inserted under the press and then a counterclockwise turn is made with the wrench. As a result, the press is lowered and grips the inserted wire end securely.

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Wago terminals are carefully designed and calculated to facilitate the wire connection. The operator only has to peel off 5-10mm of insulation from one wire or group of wires to install them

Installing the wire up to the stop in the hole provided for the wire, just press the button and release it

To test the fixing strength of the wires in the holes, pull on the wire with a small effort in an attempt to disconnect it. If the conductor is not firmly fixed, the connection must be redone. To do this, press the button and swing the wire left and right, removing from the connector

Nodes of the connection terminals dive into mounting boxes and sub-sockets in order to rationally organize the space and to protect the connections from all kinds of external influences

Before you sink a sub-socket or junction box in the selected wall recess connections should be checked multimeter. The probe is inserted into the test socket on the terminal block.

If the node with terminal connections is located in the place of possible damage, it must be covered with a plastic case or a similar device

Up to eight wires can be connected to one terminal block. In the wiring box, all connections must be arranged so that there are no crossings and overlaps

If there must be more than eight holes to connect the conductors, for example when assembling a panel, use a terminal mounting holder

Positioning of a solid conductor

Fixing the conductors in the Wago terminal

Checking the mechanical connection

Positioning of the terminals in the wiring boxes

Testing the connections connections with multimeter

Plastic cover to protect the connectors

Location of conductors in the box

The application of the mounting holder

Cage clamp #3 - the Cage clamp

It is unique, patented WAGOproduct which takes the characteristics of a cage clamp. WAGO® terminal blocks are designed for mounting cross sections of 0.5 - 35 mm.

They are not only suitable for solid conductors but also for stranded wires regardless of the fineness of the individual wires.

Terminal blocks for connecting wires: which terminal blocks are better and why

The simplest but effective terminal block design by WAGO. The figure shows the open type version, but in practice we usually have to deal with buried type set clamps

The clamp worksCage clamp simply: use a screwdriver (or a special lever in other versions) to lift the spring clamp, insert the wire under the busbar and then lower the clamp back into place. This product is of the self-clamping type.

Despite its simplicity, the manufacturer claims: the clamping force on the contact is automatically adjustable and depends directly on the wire cross section.

Cage clamp S connector #4

A version of the wire connector almost similar to the product described above. But the Cage clamp S construction is still somewhat different. The peculiarity of the \"S\" modification is shown by the possibility to work with this type of terminal without using any electrician's tools.

Plus to this, the \"S\" modification kit clamp is designed for conductors of rather high rigidity - stranded and single conductors. It is also possible to connect wires with metal end ferrules to the terminal.

Handling with Cage clamp S is very simple: the wire end (stripped) is pushed in with some force up to the stop and the connection is established.

Terminal blocks for connecting wires: which terminal blocks are better and why

Modified version of the Cage clamp S wire-connector (Figure 3). Features more convenient operation. The Cage clamp S series of wire-connectors has a place in almost all versions of group-type multi-row terminal blocks. But also the closed Cage clamp S is successfully used in high current circuits.

Terminal blocks for connecting wires: which terminal blocks are better and why

The modified \"S\" series terminal blocks are shown here. It shows step by step how the wire connection is made with a screw driver

There are two modifications of the fully encapsulated \"S\" design. One involves securing the wire by pushing the plate away from the front. The other  is designed to be executed by side pressure of a screwdriver on the spring plate.

Twist Wire Connectors

Widely used in the electrical industry, screw connectors are essentially a variation of the tubular (socket) product. They are made in the form of a rectangular tube but with a rounded (oval) bottom.

There are threaded holes in the upper plateau of such a tube, where the locking screws are screwed in. The entire structure is encased in kapron insulation. Passageways are made in the body of the insulation to access the screws. There are two types of such terminals for connecting wires - single and group.

Terminal blocks for connecting wires: which terminal blocks are better and why

Design (one of many) of a screw terminal for connecting electric wires. Closed type DIN-rail version

Wire connection screw terminals offer:

  • strong mechanical strength;
  • capable of handling cables up to 25mm cross section;
  • use in low current and power circuits.

Handling with this type of connector is easy.

The wire ends are inserted inside a brass tube and the locking screws (usually two screws) are tightened with a screwdriver. The screws in turn press the conductor to the bottom of the metal tube.

Besides terminals, there are alternative methods for connecting wires. More information on the use of terminals and other methods without soldering can be found in this article.

Conclusions and a helpful video on the subject

This video will expand your knowledge about terminal types and installation methods.

Electrical wiring works are rarely done without the accessories described. It would seem that these are small details which can easily be dispensed with by replacing the technical connection with a simple twisting of the wire.

But Electrical engineering practice is marked by many cases where exactly the trivial twisting of conductors instead of a reliable terminal connection leads to tragic consequences.

Are you experienced with wire terminals? Or still have questions about the topic? Please share your opinion and leave comments. The contact block is located below.

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