More than a hundred years ago, with the introduction of electricity into everyday life, humanity finally adopted the technogenic direction of our civilization. Now we are surrounded by various electrical appliances and equipment everywhere. Almost every house has electric wires, and if the housing is located in a remote area, then people find a way out of the situation: they install wind generators, solar panels, and so on. But not all people know that almost any electrical appliance needs an element such as a terminal box. What is it and what is it for? In the article we will try to answer these questions.
The terminal box is a rectangular or round box with a terminal block inside. Typically, the block is designed for the maximum cross-section of the switched wire (35 mm) and for the number of direct connections - 7-12 pcs.
Terminal box depending on the purposehappens:
- for dry rooms;
- for objects with aggressive environment (chemical production);
- for outdoor use (temperature and moisture resistant).
Classification of terminal boxes
1. According to the installation method, there are:
- for open installation;
- for concealed installation in concrete;
- for hidden installation in plaster, drywall.
2. Depending on materials used:
- polypropylene, ABC, self-extinguishing PVC, etc.;
- from metals.
3. By degree of protection (dust, moisture, etc.):
- boxes IP20;
- IP44, IP54, IP65;
- explosion-proof.
4. They are divided by climatic version:
- for external use U1;
- for placement under a canopy U2;
- for premises U3.
5. Depending on the form of execution, there are:
- rectangular;
- square;
- round.
6. By availability of terminal blocks:
- with terminal blocks;
- without terminal blocks.
It should also be mentioned about the instrument boxes. They are slightly larger than the terminal boxes. They allow you to place small devices, switches, sockets in addition to the pads.
The terminal box can have hermetic glands in its housing for the supply of wires and cables. Often the glands are replaced by metal or plastic pipes. Glands can be rubber with cut concentric circles or plastic to allow adjustment of the mounting hole. The use of glands can significantly increase the tightness of the product. The box is closed with a lid, which is attached to the case with screws or latches with gaskets.
All terminal boxes, depending on the purpose, application and performance, have different markings. This allows the consumer to quickly select the desired product. After all, the terminal box can be used both under water and at a height (say, five thousand meters above sea level), it can be sewn into the wall, or it can be constantly exposed to aggressive influences in the chemical industry. All this information is contained in the product code. For example, an explosion-proof terminal box is marked 1ExeIIT5. There are many types of markings even among explosion-proof boxes. The marking encodes information about the degree of explosion protection, and the place of application of the product, and much more.
