Metal boxes for electrical wiring

A metal cable box is a structure of rectangular section, flat shape, used for laying wires and cables.

Cable boxes are made of black, galvanized metal and stainless steel. Its main function is to protect wires and cables from dirt, moisture, and mechanical impact.

The metal cable box is convenient for both installation and dismantling on any surface. It is additional insulation for cable wires. The cover is easy and quick to install/remove, providing easy access to the electrical wiring in the event of any failure. The cable box set includes: a tray, a cover, a connector, as well as bolts, nuts and washers.

By choosing the right materials, you will ensure the smooth operation of the entire cable system. If cable boxes of different sizes are used in the premises, it is recommended to purchase products from the same manufacturer, because when choosing several manufacturers, there may be a problem in fastening the sections to each other, thereby breaking the tightness of the structure.

Electricians prefer to use metal boxes in their work, rather than plastic or wooden ones. And this is a logical explanation. In the event of a short circuit, plastic boxes will not only not protect the wires from further ignition, but will also contribute to it. Unlike the metal box, which guarantees fire prevention, as well as reliable protection of the cable from external actions.

Also, a tangible advantage of perforated boxes is that their installation is easier than the installation of “dull” products, since such structures can be attached to a vertical or horizontal surface with dowels or bolts directly through the holes on the walls.

Variants of the tray:

from stainless steel;
from steel, galvanized after production by means of immersion;
from steel galvanized by the Sedzimer method.

The third method is mainly used – the Sedzimer method. Its essence is that heated sheet steel is lowered into a vat of molten zinc. The steel is covered with a substantial layer of zinc. Provides steel with protection against oxidation and aging.

The main feature of this type of trays is the presence of perforations on the sides along the entire length, thanks to which the process of laying the cable is greatly simplified, as well as the installation of the tray segments one to another. Perforated trays have special holes, which helps to connect. The presence of holes and perforation excludes overheating of the cable and the possibility of further ignition.

The edges of the trays are pressed in a special way so that they can be quickly and reliably attached to each other in an overlapping manner.

Types of metal boxes

A metal box for a wire can be of several types. At the same time, these boxes differ not only in appearance, but also in the structure of the material from which they are made. The differences in the shape of the box and the method of fastening are so wide that they hardly lend themselves to description.

So:

For private households, so-called deaf or perforated boxes are most often used. They have a solid structure and completely hide communications from prying eyes. At the same time, such boxes require proper installation, because moisture can accumulate in them.

Perforated boxes are free of this drawback. They can be used in dusty rooms, because their structure does not allow dust to accumulate. But their appearance leaves much to be desired, which is why they are used much less often in private households.

The so-called mesh boxes are used for laying cable products. Their price is somewhat lower than that of boxes of the above type. At the same time, such a box practically does not protect the cables from external influences and serves only for their support.

The same function is performed by so-called stairwells. They have enough rigidity for laying a large number of power cables. And we are not talking about any kind of protection here. The last two types of boxes are intended mainly for industrial use.

As for materials, the wire box can be made of stainless steel, galvanized metal, and hot-dip galvanized steel. Here, the choice depends entirely on the operating conditions and the required durability indicators. It is clear that stainless steel boxes are the most expensive, and galvanized boxes are the cheapest.

Application of metal boxes

Use of metal boxes for hidden wiring

For hidden wiring, metal boxes are used mainly in industry. After all, they make it possible to ensure one of the most important conditions for the installation of the wire – the possibility of replacing it. After all, the box provides such an opportunity even during laying inside the walls.

Metal box for wires, according to the table. 2.1.2 PUE can be used for wires of any type. It can be any dry premises.

For humid and especially humid rooms, as well as for outdoor installation according to table. 2.1.2 steel boxes with a wall thickness of at least 2 mm should be used. At the same time, it must be possible to remove accumulated moisture and condensate.

Pay attention! The rules require a particularly careful approach to blind boxes. Connection points must be made in such a way that dust and moisture cannot penetrate into them.

What is most important, when installing metal boxes according to table. 2.1.3 PUE, no additional means of protection are required. This rule applies to both installation work on non-combustible structures and combustible materials.