Do you want to protect electrical wires by wearing a corrugated sleeve on them during installation? The cable must be protected from external damage, right? But you do not know how to mount a flexible corrugation for electrical wiring?
We will show you how to install a corrugated sleeve. Here you will find out what types of flexible channels are used for these purposes. The article discusses their pros and cons, highlights the intricacies of installing existing options for electrical pipes made of different materials.
The article is equipped with thematic photos, tips for choosing a corrugated sleeve and video recommendations for laying wires on your own are provided. Visual illustrations will greatly simplify installation and dismantling work.
Why do I need a corrugated sleeve?
Installation of wiring is a responsible and error-free business. The safety of staying in electrified rooms directly depends on its quality.
The benefits of civilization in the form of luminous bulbs and numerous household appliances, by definition, can not work without connecting to the mains. And any electric cable under voltage is a source of damaging current, dangerous to humans.
Corrugation for electric wires is recommended to be used everywhere (with a hidden and open installation method, when laying on the street and in rooms). If this is not possible 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 execution, it reliably protects a person from the current flowing through the veins.
However, insulation is not durable. It is aluminum or copper wire that can last 15–25 years, but the outer braid on them is often damaged 3-4 years after putting the wiring into operation.
The service life of the insulation of the electric wire is greatly reduced due to:
- high humidity (outdoor or indoor);
- overheating at high loads;
- ultraviolet and other factors.
As a result, breakdown, short circuit, fire and electric shock. To minimize risks, electricians also lay wires in rigid cable channels or flexible corrugated hoses. On the one hand, it serves as an additional barrier between electric current and a person, and on the other hand, it serves as a 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 doesn’t matter whether this channel is under the finish or in the concrete screed
A cable laid in a corrugated pipe receives protection from:
- squeezing and other mechanical damage;
- ultraviolet radiation and precipitation (when laying wires on the street);
- exposure to moisture.
And the last one is fire safety. This quality is especially important when wiring in a wooden house. All corrugated hoses for electrical cables are made of non-combustible or self-extinguishing materials.
This reduces the likelihood of exposure to an open flame on the wire inside the corrugation, and also prevents the spread of fire during short circuits and fire cable braid made of plastic.
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Corrugated Polymer Pipes
Corrugated Metal Channel
Varieties of polymer pipes
Wiring device in steel corrugation
Types of corrugations for electric cables
Corrugated hoses for electrical wiring are used with an open wiring device, when laying lines on the street or in a channel formed in a wooden wall. Corrugated pipes are made from various plastics and metals. There are also composite versions of iron wrapped in a layer of PVC.
For the street, it is recommended to choose one sleeve, for laying in a screed or earth another, and for installation behind interior cladding - a third.
If the wiring is laid in a dusty room and the channel for it needs to be sealed, it is best to take a sleeve made of plastic - the places of its joints with distribution boards and boxes are much easier to seal
All corrugations according to strength, wall thickness and structure are divided into:
- lungs (withstand loads up to 320 N / 5 cm2) - thin-walled, flexible and fragile, designed for laying under the skin on ceilings and walls;
- medium (rated for loads up to 750 N / 5 cm2) - recommended for installation in wall gates;
- heavy (withstand up to 1250 N / 5 cm2) - thick-walled and rigid, used when mounting wires in cable ties on the floor;
- superheavy reinforced (designed for 4000 N / 5 cm2 and above) - sleeves made from a spiral twisted steel wire and plastic sheath, are needed for laying cables underground and on the streets by hanging.
The thinner the walls of the corrugation, the softer and more flexible it is. However, with increased flexibility, the corrugated sleeve decreases resistance to mechanical damage. At the same time, it is difficult to bend a too thick-walled pipe at a right angle, it can simply break.
But such heavy corrugated hoses provide more reliable protection against 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 is obviously a more advantageous 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 hose made of metal is more fireproof and reliable than a competitor made of plastic, but it should not be laid in the ground - rust will inevitably do its dirty job
Metal corrugations for laying cables are divided into several types:
- RZ-Ts, RZ-TsH, RZ-TSA - made of galvanized steel.
- RZ-SL and RZ-SL-X - from tinned steel tape (tinplate with tin spraying).
- RZ-CPU - with PVC insulation.
Letter "X" in the first two options indicates the presence of cotton, and "AND" asbestos-cement seals. "P" in the latter type of 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 the high pressure hoses in explosion-proof design and under high pressure.
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Wooden floor with wiring in a metal hose
False ceiling wiring device
Polymer coated metal corrugation
Putting a power line into a wooden house
However, such corrugated pipes are more suitable for industrial conditions. For the installation of electrical wiring in the house they are not used because of the high price and the principle unnecessary.
Conventional metal hoses are made of steel tape by wrapping it with a spiral. At the same time, the resulting corrugation is not leakproof. With a strong press, the tape joints immediately diverge, the sleeve simply spreads to pieces.
The metal hose is ideally suited for wiring in a wooden house and outdoors in the open air, here its main plus (incombustibility) is very useful
If a metal sleeve is needed tight, then you should take a product with additional insulation from polyvinyl chloride. In this case, the top layer of self-extinguishing plastic will definitely not allow moisture and dust to the steel base.
Only such corrugations are recommended to be used in bathrooms and in outbuildings, where constant changes in humidity and temperature are the norm.
Type # 2 - Polyvinyl Chloride (PVC)
Gray electrotechnical corrugations made of PVC are characterized by low price and self-extinguishing. In a fire, they not only do not burn, but due to additives in plastic, they themselves die out.
The main disadvantage of any polyvinyl chloride products is the poor tolerance of UV rays. Under the influence of the sun, this material begins to “deteriorate”, which dramatically reduces their actual life.
Corrugated PVC pipes should be used exclusively indoors for electrical wiring according to hidden technology with laying them behind the casing or other decor
Another disadvantage of PVC corrugation is intolerance to low and too high temperatures, as well as excessive humidity. When frozen, this plastic becomes brittle. In the cold, it collapses even from a mild blow.
And in extreme heat (and even if it is in the sun), the polyvinyl chloride corrugated sleeve begins to soften slightly and “leak”. This does not lead to its immediate destruction or damage, but 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 collapse. This PVC pipe for water supply was originally designed for a similar effect, while the characteristics of corrugated pipes 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 mounting wires in dry, heated rooms. They are cheap and flexible, there should be no difficulties with laying. But their gray appearance is frankly not happy with presentability and aesthetics.
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Fake wall wiring device
Ceiling wiring packages
Monolithic polymeric corrugated sleeve
Mounting in brackets for false ceilings
From above, such corrugations are best covered with finish (wall panels, gypsum with wallpaper on top or lining).
Type # 3 - polyethylene and polypropylene
Corrugations made of polyethylene PND (or LDPE) and polypropylene PPR are approximately equal in cost and characteristics. They are resistant to strong moisture, temperature extremes and ultraviolet rays. Such corrugated hoses are universal.
They can be used both in the house and in street installation. For example, with a device for connecting a heating cable, an electrical panel when entering a site, outdoor lighting branches, activating an irrigation system, etc.
Polypropylene and polyethylene are similar in many properties, the main difference between them is that PP sleeves for cables are self-extinguishing, and from PE they are combustible
Both versions of these electrical corrugated hoses calmly feel 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.
It is recommended to use corrugated products from it in garages, utility rooms and on the streets - that is, wherever aggressive technical fluids can get on the wires.
The nuances of the choice and installation of corrugated channels
Plastic corrugations for cables are available in various colors. Gray ones are usually made of PVC, black ones from polyethylene, and blue ones from polypropylene. But strict rules in terms of color do not exist.
Each manufacturer adds dye to the polymer in the manufacture of corrugated pipes as they wish. However, there is an international standard for coloring such products and wires in them, which provides for the choice of color in accordance with the purpose of the cable route.
It is recommended to use white wires and corrugations for computer networks, gray and black for general purposes, green for telephone lines, and red - 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 immediately clear.
The following gallery of step-by-step photos will familiarize you with the procedure for laying the cable in the corrugated pipe:
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To lay electrical wiring in a corrugated pipe, we directly buy a cable, a corrugation, the meter of which will be more than the length of the designed routes by about 10% and mounting clips that are placed after 30-35 cm
We manufacture corrugated pipes taking into account their laying “without tension” and the plant of one or two rings in junction boxes and socket boxes. Cut corrugation first with a construction knife
We bite the metal probe located inside the corrugation for wiring, using wire cutters after cutting the pipe with a construction knife
Slightly pull out the probe from the corrugated pipe - a metal wire designed to pull the cable
With an awl, in the cable planned for drawing, in its insulation, we pierce the hole
We insert a probe into the hole punctured in the insulation and bend its edge with pliers or a similar tool
We press into the corrugated channel the bent edge of the probe with a cable attached to it. We try to enter as far as possible to push the wire from the opposite side of the corrugation
Grasping the edge of the probe on the opposite side of the corrugated channel, gently stretch it. Pull out so that approximately equal lengths of cable remain free on both sides
Step 1: Purchasing Corrugation Wiring Material
Step 2: Cutting the Corrugated Pipe to Size
Step 3: Biting the Metal Probe
Step 4: Pulling the edge of the metal wire
Step 5: Piercing the hole in the cable with an awl
Step 6: Pulling the Probe into the Hole
Step 7: Pressing the cable probe into the corrugation
Step 8: Pull the cable through the corrugated pipe
After pulling the cable into the corrugated channel, we proceed to fasten the lines to the building structures:
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According to the pre-made marking, we install mounting clips. for their fastening we drill holes in advance
We drive the cable through the corrugated channel into the mounting clips. Try not to stretch the line
After checking for tension or sagging along the electrical path, we snap the wiring in the mounting clips
For clips mounted on the ceiling and at the top of the walls, we are preparing additional fasteners - plastic ties
First, we’ll extend the plastic coupler under the loop, then grab the corrugated pipe with the cable with it
Once again checking the route for the absence of stretch marks and sagging, tighten the corrugated pipe and the mounting clip with a tie
All excess plastic ties obtained after tightening the pipes and clips, cut with wire cutters, leaving 2-3 mm after the clamp closed
We install all the wiring lines laid in the corrugation in an open way, following the above algorithm. After assembly, we check the system performance
Step 9: Install the mounting clips for the layout
Step 10: Insert the wiring line into the holders
Step 11: snap the corrugated pipe into the clips
Step 12: Preparing Additional Mounts
Step 13: Pulling the Tie Under the Clip
Step 14: Tighten the Loops on the Corrugation
Step 15: Cutting the Tails of the Polymer Screeds
Step 16: Complete wiring in the corrugation
For cable wiring with a cross-section of 3 × 2.5 mm², a corrugated pipe with a diameter of 16 mm and mounting clips of the appropriate size are usually purchased.
It is strictly forbidden to lay several types of cables with different purposes in one corrugated hose, it is better to use a separate pipe for each wire
Installation of corrugations and wiring in them is carried out in five stages:
- Corrugated hose and cable are cut into pieces of the desired length.
- With the help of a cable stocking, a built-in broach, or simply inserted into the pipe, the wire is drawn into the corrugation.
- Sleeves with a cable inside are fixed in a strob, on a floor or a wall.
- The laid and fixed corrugations are connected to the input holes on the cases of boxes, shields and socket boxes or simply inserted into them, and the wires are brought out.
- Next - the usual wiring of devices connected to the mains.
To simplify the installation of electrical wiring, you should look for a corrugated sleeve with a special harness (broach) inside for sale. This is an ordinary wire that was previously pulled through a corrugated pipe in a factory.
Only when cutting the corrugation, you need to be careful that this broach does not go inside. The cable on it for pulling into the sleeve is attached using conventional electrical tape.
Pulling the cable into the corrugated channel can be done even alone, but the two of them are much easier to carry out.
Metal corrugation must be grounded. And to do this is on both sides of the sleeve. The inner diameter of the corrugated pipe is selected by doubling the total cross-section of all cables laid in it. This is necessary both to simplify installation and to prevent overheating of wires inside.
The corrugation must enter the body of the socket, switch or flap flush. Any “peeping” of the cable or gaps between the end of the pipe and the housing of the installation or switchgear are not allowed.
In this case, you can forget about protecting the wiring with a corrugated sleeve. Such improper installation will only take time and money, there will be zero sense from it.
So that you can understand all the nuances of the varieties of corrugations for low-current and electric cables, we have made a selection of video materials for you on this topic.
After reviewing the following reviews and descriptions of the installation, you definitely will not have any questions about the need, types and characteristics of the implementation of electrical work using corrugated hoses.
Video # 1. The importance of installing additional insulation on the wiring in the form of a special corrugation:
Video # 2. Pulling the wire through the corrugated hose in detail:
Video # 3. Overview of different types of electrical corrugations:
Cable channels in the form of corrugated hoses are extremely easy to install. They are inexpensive, and the benefits of such additional protection for wiring are enormous.
The cost of repairs in the event of a fire from a short circuit will obviously be higher. The pull through the wiring sleeve of the cable only at first glance looks complicated. Everything can be done independently.
Please write comments in the block below. Tell us about how you built or repaired the wiring using the corrugation as a cable channel. Perhaps you have questions, have useful information and photos on the topic of the article?