Do you want to protect the electrical wires by putting a corrugated sleeve on them when mounting? Cable protection against external damage must be ensured, right? But you do not know how to properly assemble the flexible corrugation for wiring?
We will show you how to install the corrugated sleeve. You will learn from us what types of flexible channels are used for these purposes, their pros and cons are disassembled. The article highlights the subtleties of the installation of existing variants of electrical pipes made of different materials.
The article is equipped with thematic photos, tips on choosing a corrugated hose and video recommendation on how to lay wires on its own are given. Visual illustrations greatly simplify the installation and dismantling.
The content of the article:
- Why do I need a corrugated?
Types of corrugations for electrical cables
- Type # 1 - metal hose
- Type # 2 - Polyvinyl Chloride (PVC)
- Type # 3 - Polyethylene and Polypropylene
- Nuances of selection and installation of corrugated channels
- Conclusions and useful video on the topic
Why do I need a corrugated?
Electrical installation is a matter of responsibility and not tolerating errors. Safety of stay in electrified premises directly depends on its quality.
The blessings of civilization in the form of luminous bulbs and numerous household appliances, by definition, cannot work without being connected to the electrical grid. And any electrical cable under voltage is a source of damaging current, dangerous to humans.
It is recommended to use corrugation for electrical wires everywhere (with hidden and open installation methods, when laying outdoors and indoors). If this is impossible for aesthetic reasons, then it should be replaced with a decorative cable channel.
The first protection against electric shock is the insulating sheath of the cable itself. Regardless of the material of the performance, it reliably protects the person from the current flowing through the veins.
However, the insulation is not durable. This aluminum or copper wire can last for 15-25 years, but the outer braid on them is often damaged within 3-4 years after commissioning wiring.
The service life of the insulation of the electric wire is greatly reduced due to:
- high humidity (outdoor or room);
- overheating at increased loads;
- ultraviolet and other factors.
The result - a breakdown, circuit, fire and electric shock person. To minimize the risks, electricians and lay the wires in hard cable channels or flexible corrugated sleeves. On the one hand, it serves as an additional barrier between electric current and a person, and on the other hand, it serves as cable protection.
If it becomes necessary to replace the old wire in the corrugation, it is simply pulled out of the sleeve, and a new one is inserted in its place - and it does not matter whether this channel is under the trim or in the concrete screed
The cable laid in a corrugated pipe receives protection from:
- squeezing and other mechanical damage;
- ultraviolet and precipitation (when laying wires on the street);
- moisture exposure.
And the last - fire safety. This quality is especially important when laying wiring in a wooden house. All corrugated sleeves for electrical cables are made of non-combustible or self-extinguishing materials.
This reduces the likelihood of an open flame on the wire inside the corrugations, and also prevents the spread of fire in the event of short circuits and fires of plastic cable sheath.
Types of corrugations for electrical cables
Gofrorukava for electrical wiring is used when open wiring devicewhen laying lines on the street or in a channel formed in a wooden wall. Corrugated pipes from various plastics and metals are produced. There are composite versions of iron wrapped with a layer of PVC.
For the street, it is recommended to choose one sleeve, for laying in a screed or ground another, and for mounting behind an interior facing - the third.
If the wiring is laid in a dusty room and a duct is required for it, then it is best to take plastic sleeve - its joints with distribution panels and boxes are much easier to seal
All corrugations on strength, wall thickness and design are divided into:
- lungs (withstand loads up to 320 N / 5 cm2) - thin-walled, flexible and fragile, designed for laying under the cladding on the ceilings and walls;
- medium (designed for loads up to 750 N / 5 cm2) - recommended for installation in wall chitches;
- heavy (stand up to 1250 N / 5 cm2) - thick-walled and rigid, used when installing wires in screeds on the floor;
- super heavy reinforced (designed for 4000 N / 5 cm2 and above) - sleeves made of coiled steel wire and plastic sheathing are needed for laying cables underground and on the streets by hanging.
The thinner the walls of the corrugations, the softer and more flexible it is. However, with an increase in the flexibility of the corrugated sleeve, the resistance to mechanical damage decreases. In this case, too thick-walled pipe is difficult to bend at a right angle, it can simply break.
But such heavy corrugated provide more reliable protection from moisture and dust. This is especially true when laying cables in the ground.
Type # 1 - metal hose
Metal in terms of strength when compared with plastics - certainly a better option. It perfectly protects the cable from the effects of chemistry, moisture, ultraviolet radiation, shock and compression. And in case of fire, the metal hose will last much longer than the plastic counterpart.
A corrugated metal sleeve is more fireproof and reliable than a plastic competitor, but you shouldn’t put it into the ground - rust will inevitably do its “dirty” business
Metal corrugations for cable laying are divided into several types:
- РЗ-Ц, РЗ-ЦХ, РЗ-ЦА - from galvanized steel.
- РЗ-СЛ and РЗ-СЛ-Х - from a steel tinned tape (a white tin with a tin dusting).
- RZ-CPU - PVC insulated.
Letter "X" in the first two variants indicates the presence of cotton, and "BUT" asbestos cement seal. "P" in the latter type, the corrugation indicates the outer layer of PVC.
Also, metal hoses for wires exist with flanges at the ends and ends for welding. Plus, there are variations of high-pressure explosion-proof RVD.
However, such corrugated pipes are more designed for industrial conditions. For installation of electrical wiring in the house they are not used because of the high price and the basic uselessness.
Conventional metal sleeves are made of steel tape by winding it into a coil. In this case, the resulting corrugation does not differ tightness. With a strong push, the tape joints instantly diverge, the sleeve simply crawls apart.
The metal hose is ideal for the installation of electrical wiring in a wooden house and outdoors in the open air, here its main advantage (non-combustibility) is just the way
If you need a metal sleeve sealed, you should take the product with additional insulation of polyvinyl chloride. In this case, the top layer of self-extinguishing plastic exactly will not allow moisture and dust to the steel base.
Only such corrugations are recommended for use in bathrooms and in outbuildings, where constant changes in humidity and temperature are the norm.
Type # 2 - Polyvinyl Chloride (PVC)
Gray electrical PVC corrugations have a low price and self-extinguishing. In the event of a fire, they do not just not burn, but by themselves in plastic additives fade out.
The main drawback of any PVC products is poor tolerance of UV rays. Under the influence of the sun, this material begins to trite "deteriorate", which sharply reduces the actual period of their service.
Corrugated PVC pipes should be used exclusively indoors for electrical wiring using a hidden technology with their laying behind the plating or other decor
Another disadvantage of PVC corrugation - intolerance to low and too high temperatures, as well as excessive moisture. When freezing, this plastic becomes brittle. In the cold, it collapses even from a light blow.
And in case of strong heat (and even if it is in the sun), a corrugated polyvinyl chloride sleeve begins to soften slightly and “flow”. This does not lead to its immediate destruction or damage, however, its service life is sharply reduced due to such operating conditions.
A similar situation with water. With constant exposure to moisture, the walls of such corrugations begin to gradually break down. This PVC pipe for water supply was originally designed for a similar effect, while for corrugated sleeves the characteristics are somewhat different.
If the wiring must be laid in the bathroom or on the street in direct sunlight, it is better to look for another version of the cable channel for it.
Corrugated PVC pipes are ideal for wiring in dry heated rooms. They are cheap and flexible, with gasket should not be difficult. But their gray appearance is frankly not happy with presentability and aesthetics.
From above, such corrugations are best closed with a finish (wall panels, plaster with wallpaper on top or clapboard).
Type # 3 - Polyethylene and Polypropylene
Corrugated polyethylene HDPE (or LDPE) and PPR polypropylene are approximately equal in cost and performance. They are resistant to strong moisture, temperature extremes and ultraviolet rays. Such corrugated sleeves are universal.
They can be applied both in the house, and at street installation. For example, when connecting the device line heating cable, electric switchboard when entering the plot, branches of outdoor lighting, activating the irrigation system, etc.
Polypropylene and polyethylene are similar in many properties, the main difference between them is the PP cable sleeves are self-extinguishing and PE is flammable.
Both variants of these electrical corrugated sleeves feel comfortable at air temperatures in the range of -40... + 45 degrees Celsius. At the same time PND is famous for its resistance to oils, acids and solvents.
Corrugated products from it is recommended to use in garages, utility rooms and on the streets - that is, everywhere where aggressive technical fluids can get on the wires.
Nuances of selection and installation of corrugated channels
Plastic corrugations for cables are available in various colors. Gray is usually made of PVC, black is polyethylene, and blue is polypropylene. But strict rules in terms of color does not exist.
Each manufacturer adds a colorant to the polymer in the manufacture of corrugated pipes at its discretion. However, there is an international standard for coloring these products and wires in them, which provides for the choice of color in accordance with the purpose of the cable route.
White wires and corrugations are recommended to be used for computer networks, gray and black for general use, green for telephone lines, and red ones - exclusively for outdoor street installation.
Following these recommendations greatly simplifies the life of electricians when they come to make repairs in an unfamiliar place. So the direction of each line is clear immediately.
Several types of cables with different purposes in one corrugated sleeve are strictly prohibited to be laid, it is better to use a separate pipe for each wire
Installation of the corrugation and electrical wiring in them is made in five stages:
- Corrugated hose and cable is cut into segments of the desired length.
- With the help of a cable stocking, built-in broach, or just a wire inserted into the pipe, the wire is pulled into the corrugation.
- Sleeves with a cable inside are fixed in a shtrob, on a floor or a wall.
- The laid and fixed corrugations are connected to the inlet openings on the cases of boxes, shields and bottom plates, or simply inserted into them, and the wires are brought out.
- Further - the usual electrical installation of devices connected to the mains.
To simplify yourself electrical installation, in the sale of corrugated sleeve should be searched with a special plait (broach) inside. This is a common wire that was previously stretched through a corrugated pipe in a factory.
Only when cutting corrugations, you need to be careful that this broach does not go inside. The cable on it for pulling into the sleeve is attached with a conventional electrical tape.
It is possible to cope with cable pulling into the corrugated channel even alone, but the two of you can perform this procedure much easier.
Metal corrugation must be grounded. And it is worth doing on both sides of the sleeves. The inner diameter of the corrugated pipe is selected by doubling the total cross-section of all cables laid into it. This is necessary both to simplify installation and to prevent overheating of the wires inside.
The corrugation must be flush with the socket, switch or shield. Any “peeping” of the cable or gaps between the end of the pipe and the body of the installation or distribution device are not allowed.
In this case, you can forget about the protection of wiring corrugated. Such a wrong installation only takes time and money, the sense of it will be zero.
Conclusions and useful video on the topic
So that you can understand all the nuances of the corrugations for low-current and electrical cables, we have made for you a selection of video materials on this topic.
After reviewing the following reviews and descriptions of the installation, you just do not have questions about the relevance, types and features of the electrical work with corrugated sleeves.
Video # 1. The importance of installing additional insulation on electrical wiring in the form of special corrugations:
Video # 2. Wire pulling through a corrugated sleeve in detail:
Video # 3. Overview of different types of electrical corrugations:
Cable channels in the form of corrugated sleeves are extremely simple to install. They are inexpensive, and the benefits of such additional protection for wiring are enormous..
The cost of repair in case of fire from a short circuit will obviously be higher. Pulling through the cable sleeve only at first glance looks complicated. Everything can be done independently.
Please write comments in the box below. Tell us how you constructed or repaired the wiring using corrugations as a cable channel. Perhaps you have any questions, have useful information and photos on the topic of the article?