Plastic and metal corrugated pipe for electrical wiring
When laying electrical wiring cables, a corrugation or metal hose is often or even almost always used. These are materials that are partly similar and partly different from each other. Where and how the corrugated pipe is used for electrical wiring will be described in this article.
What is a corrugated pipe
- The corrugated pipe for electrical wiring has a high resistance to external factors. Thick-walled sections provide high impact resistance.
- The pipe stretches easily.
- When stretching or twisting the corrugation, the electrical cable placed inside it is not affected by these mechanical factors.
It should be noted that the corrugated pipe for the cable, which is widely used when laying electrical wiring, can be different. The differences of the corrugations from each other make it possible to use it for different purposes and for different cables.
What is a corrugated pipe for electrical wiring
Corrugated pipe, depending on the materials of manufacture, can be of two types:
- plastic;
- metal.
Plastic corrugation has the following advantages:
- High strength.
- The corrugation for the cable protects people from electric shock.
- It is fireproof.
- Protects the cable from exposure to water and air with high humidity.
- Can be laid in any premises, along lines with any turns.
Nevertheless, the plastic corrugation for the cable has one serious drawback: it cannot be used outdoors or in rooms with unstable temperature conditions, since the corrugation bursts and breaks due to sudden temperature changes or exposure to subzero temperatures. Its further use becomes impossible, since the pipe ceases to fulfill its functions.
The metal hose is used for the same purpose as the plastic corrugation. Of the differences between these two pipes, one can single out the fact that the metal corrugation for the cable easily tolerates temperature changes, it can be used outdoors. This sleeve is considered to be more reliable, however, unfortunately, it is also more expensive, which makes its use more rare. In some cases, its use is impractical or even impossible due to its technical characteristics. So, corrugated pipes for electrical wiring, made of metal, can rust, so they should not be laid in the grooves of plastered walls. For this, a plastic corrugation is used. The corrugation made of plastic, depending on the thickness of the thick-walled sections and the pipe diameter, is intended for different purposes. It also differs in withstanding loads.
Variety of plastic corrugated pipes
Plastic corrugation for a cable, depending on its thickness, is designed not only for cables of different thicknesses, but also for different loads assumed on the plastic sleeve. So, the load is calculated based on their compressive resistance under certain conditions. Measurement at a temperature of 20 ° C is considered standard, and depending on the wall thickness, it can be different.Depending on this parameter, the classification implies the presence of such types of corrugation:
- lightweight;
- easy;
- heavy;
- super heavy.
The most common use in home wiring is the use of a corrugated pipe from a light series. This pipe is designed to withstand a load of 350 N over 5 cm of length.
The corrugation from the heavy and superheavy series is designed for pouring into concrete and for use when laying hidden electrical wiring in houses with monolithic-frame housing construction. This pipe can withstand loads from 750 N to 1250 N (depending on series and diameter.)
Corrugated plastic wiring pipes can be of different diameters. The most standard diameters are from 16 to 50 mm. When calculating the required diameter of the corrugation, it must be borne in mind that the diameter given in the technical characteristics of the product indicates the outer diameter of the pipe measured over the section of the thick-walled ring. The difference in the inner diameter to the smaller side in comparison with the outer one can be up to several mm. Therefore, having calculated the total diameter of the electrical cables that will be laid in the corrugation, you need to choose a pipe with diameters several mm larger, and the larger the diameter of the electrical cables, the larger the diameter of the corrugation.
So, for a corrugated hose for electrical wiring with an indication in the technical characteristics of a diameter of 0.16 cm, the inner one will be only 1.07 cm, and for an outer ring of 2.0 cm, the inner one will be 1.41 cm. In the same way, the diameters of other corrugations are calculated. They are 2.50 and 1.83 cm, respectively, 3.20 and 2.45 cm, respectively, 4.0 and 3.15 cm, respectively, 5.0 and 3.96 cm, respectively. In the same way, for a metal hose, the data for the outer and inner diameters also differ. When choosing the dimensions of the corrugation for the cable, these data should be taken into account.
Differences between metal hoses
According to the data indicating the differences between the outer and inner diameters of the tight ring of the plastic sleeve, the metal hose also has distinctive characteristics of these data. When calculating the inner diameter of a sleeve made of metal, you must rely on the data specified by the technical manufacturer. Data for metal hoses and rubber crimps may differ. For a metal hose with an outer diameter of a thick-walled ring of 1.35 cm, the inner diameter will be only 0.97 cm, and for an outer diameter of 5.8 cm - 4.95 cm of the inner diameter.
Packing and transportation
Corrugations, both plastic and metal, are supplied in coils. These coils can have different diameters, depending on the diameter of the thickest ring. Thus, a light-type corrugation can be supplied in coils with a total length of the pipe itself from 50 to 100 meters. The heavy-duty sealing sleeve is supplied in coils ranging from 2 to 25 meters long.
In most cases, for ease of transportation, coils are packed by wrapping them in a film with a heat shrink effect. This protects the material from damage and contamination during transportation.
As you can see from the information described in this article, when choosing which corrugation to use to protect the cable when laying electrical wiring, you need to take into account many factors. Among them are the diameter and purpose of the cable, the impact resistance of a particular corrugation, its intended purpose, the need to roll the sleeve into concrete structures or wall grooves, and so on. Particular attention should also be paid to the difference in diameters along the outer circumference of the thick-walled ring and the inner one. By choosing the right corrugation or metal hose for the cable, you can provide additional insulation for the wiring.