Electrical wiring terminals: what is it and whyIt is difficult to imagine our life without electrical appliances, and, of course, without electricity in general. During the construction of the premises, the builders lay electric wires through the walls, in accordance with a special scheme, and also establish the point of their branches. The place of collection of all electrical conductors is placed in a special box called a terminal box.


  • 1 Junction box - what is it?
  • 2 Types of terminal blocks
    • 2.1 Self-tightening terminal blocks
    • 2.2 Screw terminal blocks
    • 2.3 Advantages and disadvantages of terminal blocks
  • 3 How to choose terminal blocks?

Junction box - what is it?

When installing electrical wiring it is impossible to do without the terminal box. It is intended for reliable and safe connection of all electrical wires, in accordance with the previously drawn wiring diagram in the room. Exists two common types of terminal boxes depending on the method and installation scheme - for hidden wiring and for open.

Most often in the modern world, the first type of terminal boxes is used, when all electrical wiring hides under the walls. Installation of hidden wiring is not an easy process, which must be treated with special responsibility and care. Otherwise, after installation you may have a lot of problems, and fix them will be very difficult, because the wires will be hidden under the walls.

The terminal box is used to collect all electrical wires in one place. And nowadays, when the number of wires in a room can reach several dozen, this element is simply necessary. Enclosed box wires are connected using special terminalsthat guarantee the reliability and security of the connection.

What are the terminals for?

The main purpose of all terminals is the connection of wires into one, taking into account their features and electrochemical characteristics. Regardless of the design, the terminal block should provide high-quality and reliable connection of wires in the terminal box, to prevent short circuits or breakdowns.

Types of terminal blocks

Nowadays, two main types of terminal blocks are most often used - self-tightening and screw connecting terminal blocks.

Self-tightening terminal blocks

Wiring box installationSelf-tightening terminal blocks characterized by particular simplicity and convenience in terms of electrical wiring in the terminal box. Even a person with insufficient qualifications will be able to understand the design of the self-tightening terminal block and seamlessly connect the two wires in the box. When choosing this connecting element, it is necessary to pay attention to the thickness of the hole through which the electrical wire will shortly drain.

In ordinary rooms with a current of 24A, 0.75-2 square meters are most often used. mm terminal blocks. This type of terminal blocks is found with a different number of outputs - from two to ten. Such an amount is usually quite sufficient for the further replacement of conductors.

It is worth noting that all self-tightening terminal blocks are made of quality plastic onlythat defies burning.

Screw terminal blocks

How to make a connection in the boxThis type of connecting terminals is also actively used in the electrical installation field, but as the experience says, there are many problems with them. The material used for the production of screw terminal blocks is used:

  • polypropylene;
  • polyamide;
  • polycarbonate and other materials.

The main disadvantage of connecting screw terminal blocks are all kinds of installation difficulties in places with insufficient free space. For reliable fixation of wires it is necessary to use a screwdriver and bolts. Besides not very hard aluminum wires are clamped with a screwwhich may cause short circuits or fatal wire breakage.

The advantage of screw terminal blocks for terminal boxes is a relatively low cost, as well as the ability to connect wires from different materials.

In the modern world, another type of terminal strip is used - SZI (connecting-isolating clip). SZI is a fairly simple and understandable device that can only be used to connect two wires. The connection is made by twisting the wires into a pigtailafter which the cap is placed on them when applying the appropriate thread.

Despite the fact that this type of terminal blocks for terminal boxes is very simple and understandable, under heavy loads it will not be able to cope with heating.

Advantages and disadvantages of terminal blocks

  1. The most important advantage of terminal blocks for terminal boxes is the reliability and safety of the connection.
  2. It is also worth noting that even with time the resistance of the circuit does not change and does not increase. If the connection will be made using stranding, then in the near future in the contact area the wire may oxidize, stretch or deform. Thereby resistance may increase, and the contact itself overheats and there is a risk of fire. In the case of terminal blocks for terminal boxes, this is excluded.
  3. The design of the terminal blocks is very simple and clear and its installation does not take you much time.
  4. Maximum protection against overheating and fire due to high-quality fixation and application of heat-conducting substrate.

The only drawback terminal is considered need for additional spacewhen it comes to multiple wires.

How to choose terminal blocks?

Terminal blocks: types.In order not to be mistaken when choosing terminals for terminal boxes, you must first deal with all the features of the upcoming purchase. The first step is to understand for what functions the connector will be used. Then you need to take into account such factors as cable section, number of connections and sequence. Only after you take into account all these factors, you can make the final choice.

As a rule, its technical parameters, as well as the maximum allowable values ​​of voltage and current, are always indicated on the terminal strip. Exactly these indicators need to pay attention when making a purchase, because they must be ideally suited to the existing wiring.

Installation of wiring in the house should be performed with the highest quality and correct, as this will be the key to safety and comfort for many years. The use of terminal blocks for terminal boxes is good way to secure reliable and safe wiring own hands.