Corrugation is a special type of protection of electrical wires from mechanical stress. Prevents the spread of fire during a short circuit in the network. Corrugation for wires serves as additional insulation of power cables, which eliminates the possibility of electric shock if the integrity of their insulation is damaged.
Corrugation: definition
The corrugated hose or corrugation is a hollow tube of a special shape that protects the wires from fractures and prevents them from getting wet. This type of product appeared on the markets relatively recently, at the end of the last century.
Outwardly, the corrugation for wires looks like an alternation of rings: dense wide and thin, smaller in diameter. In a section, the tube resembles a comb with protrusions. This ensures sufficient rigidity under transverse loads, it is provided by dense outer rings and flexibility due to thin inner rings.
Production material
The material for making corrugations can be different. Use:
- polyvinyl chloride, which is practically resistant to combustion;
- low-pressure polyethylene - bends perfectly;
- high-pressure polyethylene - used for the production of two-layer corrugations;
- polypropylene - used in monolithic construction for the installation of electrically conductive channels;
- polyamide - provides more reliable protection against water.
The industry has mastered the production of corrugations not only plastic, but also metal. Of course, it is stronger at a break, more resistant to low temperatures. But there are some drawbacks: this corrugation is prone to oxidation, sensitive to precipitation, conductive. Stainless steel pipes for laying cables because of their high cost are used much less often. Metal protection costs several times more than a plastic corrugation. The price can reach tens of thousands of rubles.
Types of corrugation
Pipes differ in design features:
- single-layer, the inner wall serves as the basis for the surface;
- two-layer, outside the corrugation, inside a flexible tube with a smooth surface.
The modification of a two-layer corrugation can be different: for one wire or several at once. In this case, the inner smooth tube has a number of cells isolated from each other.
Another performance classification:
- Lightweight, very flexible with thin walls. Mainly used for mounting cables on walls and ceilings under the casing.
- Reinforced - heavy corrugated pipes with thick walls, increased strength. Such corrugation is used for wires on the street, in a concrete-cement screed, when laying the cable underground or in a concrete floor.
Dimensions
The corrugated pipe is released in bays of different lengths: 15, 20, 25, 50 and 100 meters. They are sealed in sealed bags from a special (heat-shrink) plastic film. A rigid pipe is cut into pieces 2-3 meters long.
There is a different corrugation for wires. Diameters of pipes can be from 16 mm to 63 mm. The following sizes are recommended:
- 16 mm - for signaling and telephone communication wires, lighting devices;
- 20 mm - for sockets and switches;
- 25 mm - for connecting shields with junction boxes ;
- 50 mm - for wiring between floors.
Determining the required diameter is not difficult. A wire or several is placed in a piece of pipe, if installation requires it. Half of the internal volume of the corrugation should be free - this is the desired diameter. Using correctly selected pipes, you can mount computer or television networks.
Corrugation Properties
Regardless of the design, diameter and modification, the plastic corrugation for wires has the following properties:
- not subject to decay and corrosion;
- burns badly;
- durable, service life up to 50 years;
- resistant to mechanical damage (shock);
- it is not affected by environmental factors ;
- environmentally friendly and safe;
- easy to install;
- provides reliable protection of electrical wiring at temperature drops from - 20 0 to + 55 0 ,
- has high chemical resistance;
- allows you to quickly replace a damaged cable;
- light weight provides easy transportation;
- does not conduct electricity;
- Helps to avoid rupture and deformation of wires during shrinkage of the building;
- Perfectly protects from water.
In addition, the color of the corrugation may be different. The main ones include red, black and gray, but the choice can be much wider.
For internal wiring, the choice of insulation is obvious - corrugation. The price is affordable for any consumer. Depending on a number of characteristics, it can range from 50 rubles per linear meter to several hundred.
Mounting
Corrugation for wires is widely used in the installation of the power grid both indoors and outdoors. The wires can be laid open or closed (hidden behind a suspended ceiling, plasterboard walls, in a concrete floor or gates, underground) in a way.
With open installation, the corrugation is attached to the base with the help of special clamps. The ability of the corrugated material to easily bend significantly reduces the number of fasteners and connection elements. With the closed method, cement mortar can be used to fix the pipe, and concrete can also be used on the floor.
Installation is not difficult, any beginner can handle it. Only some dexterity and caution are required when pulling the cable into the pipe.
Laying the wire in the corrugation does not take much time. After the final installation, the pipes begin to assemble the mains itself. If this is a floor covering, then the wiring is pulled after the final solidification of the solution into which the rigid pipe is mounted.
Pulling the wire into the corrugation
The instructions describe how to extend the wire into the corrugation. For this, a simple device in the form of a thin steel wire is provided in the pipe itself . There is a corrugated pipe on sale without a conductor, it costs less. The end of the electric wire is securely twisted with a broach and very carefully, without sharp jerks, pass the cable through the pipe.
If suddenly a break occurs, you will have to cut the pipe, again twist the cable and cable together and continue to work.
When mounting the corrugation in the floor, its diameter should always be considered. It is better that the wires pass freely in the pipe, this will greatly facilitate the work and prevent the cable from getting stuck. If it is necessary to insert several wires, then they are drawn at once, all together.
The universality of the corrugated pipe as a protective casing for electric networks is so high that it is difficult to list all areas of its application. Use in everyday life helps to avoid many troubles - fires from short circuits in the mains or electric shock in case of wire breakage.
This is especially true for wooden houses in the private sector. Correctly selected in color and neatly mounted corrugation will not spoil the appearance of the structure and provide reliable protection of the mains.