- A little about wires
- Possible wire problems in unprotected walls
- The most popular ways to protect the track
- Corrugated pipe (corrugated pipe, corrugation)
- Plastic pipe
- Armor sleeve metal
The article describes the main measures to protect electrical wiring from problems. You will learn about the advantages and disadvantages of different channel device options, as well as about the dangers of laying an unprotected cable into walls and screeds. The article also provides prices for cable protection.
It is difficult to imagine external wiring of two twisted wires running under the ceiling, although it is this outdated type of highway that is the safest. Over time, the wires become more and more perfect and allow them to be laid in boxes, filled with ties and walled up in walls. How not to harm your home during electrical work, we will tell you further.
A little about wires
According to the material, the wires are of different types, but for the household network two are usually used – aluminum and copper. The first, although less flexible, keeps its shape better after bending. The second has the best performance in terms of current carrying capacity, but costs more.
By their structure, the wires are monolithic and multi-core (twisted and braided). The monolith conducts current better, and it is easier to lay a stranded wire in a confined space, for example, in the body of a household appliance. Aluminum wires are only monolithic. To pass a current of 2.2 kW (10 A), a copper wire with a cross section of 1 mm is required2, or aluminum wire with a cross section of 1.3 mm2.
Possible wire problems in unprotected walls
Overheating or fire.Occurs in wires due to overloads, especially if they are systematic and / or continuous. In this case, the cable insulation first collapses (melts or burns), and then the temperature is transferred to the surrounding space..
Short circuit.A common cause of fires due to old wiring. The metal of the cable tends to wear out and lose its cross section. If the loss of 10% of the cross-section on the highway is most often acceptable (it is extinguished by the margin taken in the calculations), then on the twists in the distribution nodes this leads to a weakening of the contact and, as a result, the appearance of an electric arc or sparks. If there is wallpaper, wood or other combustible material around such a place, fire cannot be avoided..
Note.Every electrician knows that wires need to be soldered when wiring, but in practice this is not always done. Contact terminals do not solve the problem – the “thinned” wire can come out of it.
Accidental highway violation.This refers to the drilling of walls and screeds “at random”, without checking with a cable detector. Only strong protection will protect the wire from breaking through with a drill.
Excessive heating of the wire.They try to make walls and screeds from materials with low thermal conductivity, but none of them can compare in thermal insulation with the air itself *. The heated wire transfers heat to the solid material, which also begins to heat up – this leads to premature wear of the wires. If this continues long enough, the wire melts under excessive temperature and a short circuit occurs..
* All heaters are formed air cells.
Unlike concealed installation of an unprotected cable, laying it in a hollow sleeve makes it possible to compensate for heating due to the supply of air.
The most popular ways to protect the track
Corrugated pipe (corrugated pipe, corrugation)
It is a flexible plastic thin-walled tube with a cross section of 16 to 63 mm. The most versatile and common way to protect a cable. It is delivered in coils of 5–500 m and has a pull-out wire laid inside. To place a wire or a group of wires in a corrugation, it is enough to fix the wire at one end of the wire and pull it out of the corrugation – the wire will stretch behind it.
The cable is placed in the corrugation before installation. It is suitable for any type of wiring, but practice has shown that it is most convenient to use it with flexible wires – low-current, twisted up to 2.5 mm2, telephone, monolithic up to 1.5 mm2.
- Ease of installation.
- Easy to cut.
- Most affordable cost.
- Least protection.
- Brittleness (tightness may be broken).
- It is difficult to push the wire through it – the ribs interfere.
* Refers to low and medium price categories. Expensive corrugation is quite durable, non-combustible, there are also frost-resistant models.
In general, the corrugation satisfies all the needs for the protection of household wiring – it can be concreted, laid in frame walls, or put outside instead of a cable channel.
Table. Approximate prices for Russian-made thin-walled corrugation
Diameter, mm Price 1 rm. m, y. e. sixteen 0.5 20 0.7 thirty 0.8 35 0.9 40 1 50 1.1 63 1,2
This is an ordinary smooth-walled technical polyethylene pipe. Wall thickness from 1 to 3.5 mm, diameter from 16 to 50 mm. Wire range: twisted – any section and shape, monolith – up to 20 mm2.
- Creates a reliable channel that is difficult to invisibly damage even with a drill.
- Strong walls eliminate leakage or accidental damage.
- Conveniently push the wire along smooth walls.
- Inflexible, because of this – a narrow field of application, more often technical objects.
- When bending, it can happen in a hall, which will complicate further work.
As a channel, you can use any technical pipe – water supply, sewer or drain. However, stacking it in a gutter can be too time consuming. If the diameter is too large, split the wire group into two thinner pieces.
Scope of application – any objects that fit the technical properties of the pipe that do not have a fire, explosion or thermal hazard..
Table. Plastic pipe prices
Diameter, mm Price 1 rm. m, y. e. sixteen 0.7 20 0.8 25 0.9 40 1,2 50 1.4
Armor sleeve metal
It is a flexible metal hose, sometimes with a plastic tube inside. It is designed to prevent physical damage to the track, but it can also perform sealing functions. Diameter – from 12 to 26 mm.
- Best protection against damage.
- Does not burn or melt.
- Reliably keeps temperature.
- High price.
- Corroded *.
* There is a product in anti-corrosion design, but it costs an order of magnitude more.
Armored sleeve (metal hose) is used in places of fire or thermal hazard, in transport. In suburban housing construction, it is recommended to use it when laying hidden wiring in walls made of solid wood material (timber, log).
Table. Armored sleeve prices
Brand Diameter, mm Price 1 rm. m, y. e. “Svetozar” IP65 15 0.8 “Svetozar” IP65 20 0.9 “Svetozar” IP65 25 1.1 P3-CA (anticorrosive) 20 1.1 P3-CA (anticorrosive) 22 1.25 P3-CA (anticorrosive) 25 1.35 P3-CA (anticorrosive) 32 1.7
The descriptions do not mention tightness for nothing. This is one of the main requirements for highways laid in protection. In a sealed air system, overheating does not cause ignition, since there is no access to oxygen for combustion. Consider this fact when installing electrical wiring.