Is it necessary to lay the cable in a corrugated pipe when installing electrical wiring?

In what cases is corrugation needed when laying cables?

Corrugation is a special pipe of a special shape, which is characterized by increased flexibility and can be made of polymer PVC plastic, polypropylene, polyethylene, polyamides or metal.

The main function of the corrugation is to provide protection for electrical wiring in a private house, apartment, or any other place where cable and wire products are installed from mechanical influences, the influence of precipitation, moisture, UV radiation and other negative factors. Having the ability to self-extinguish, the corrugation takes the first “blow” if the power line ignites.

Let's consider situations where the use of corrugated pipes is strictly regulated by regulations and is simply rational:

• installation of exposed electrical wiring indoors on non-flammable surfaces (concrete, brick, etc.). To lay cables on wooden planes, you will need a special substrate made of a material that does not ignite, or ordinary metal corrugation;
• laying cables in a hidden way in rooms, for example, in a concrete pour, is recommended to be supplemented with corrugated protection;
• installation of external electrical routes, including overhead ones. Important: you should choose a corrugated pipe that is not afraid of UV rays;
• laying unarmored cables in the ground. For these purposes, you will need stainless metal or HDPE corrugation;
• installation of electrical routes in areas with a high probability of causing damage to cable products;
• creation of moving parts of an electrical circuit;
• planning to replace the cable line in the future (to simplify installation, the corrugation can be taken a larger size).

Corrugation for wires: design and materials

Corrugated pipe for cable is used for installation of all kinds of lines, as well as for various wiring options: disguised, underground and external. They differ in their design, technology and raw materials.

The following types of materials can be used:

HDPE is a flexible wire;

Application of HDPE material

• polyvinyl chloride is a self-extinguishing type of raw material;
• pnd is used for hidden lines. It is laid in concrete structures or bricks;
• polypropylene is a plastic line that is used to install the cable;
• polyamide provides good waterproofing.

Structure of a polyamide product

If the wiring is laid over flammable types of material, then heat-resistant metal corrugation is used. Pipes can have different designs. In the single-layer version, the main has one wall between the outer and inner surfaces. A two-layer product has an inner layer that is placed in a protective casing.

Corrugated wires are in demand due to many advantages:

• long service life;
• does not allow moisture to pass through;
• fire resistance;
• increased resistance to various types of load;
• does not corrode;
• light weight.

Electric wires

Standards and rules for laying cables in corrugated cables

The requirements of state regulatory documents do not directly indicate the need to lay electrical cables in corrugation. However, from some standards one can draw clear conclusions about the use of corrugated pipes. For example:

- in table 2.1.3 PUE

(Fig. 1) it is recommended to install unprotected and protected cable and wire products in pipes made of difficult/non-combustible materials;

— clause 7.1.37 PUE

indicates that electrical wiring in the premises must be replaceable. It is easier to do this if the method of pulling the cable in a corrugation is used, because the procedure for replacing an electrical line that is laid in a groove or embedded is very labor-intensive;

— clause 3.58 SNiP 3.05.06-85

obliges to take measures to protect cable lines from mechanical damage.

Features of installation of electrical wiring in corrugated open method

When installing open electrical wiring in accordance with the requirements of the PUE, the distance from the corrugated pipe to the combustible base must be at least ten millimeters. It is clear that, for example, in a wooden house such a condition cannot be met without the use of special gaskets. Penofol, which has the most balanced combination of price and quality, is often used for such purposes. It should be taken into account that in order to comply with fire safety requirements, the gasket must protrude 10 mm in all directions from the border of the plastic corrugation.

According to the PUE, installation of open electrical wiring in rooms at a height of two meters above the surface is allowed. The use of corrugations allows you to circumvent this limitation, since they all have the necessary degree of strength to protect cables from damage by penetrating objects with a diameter exceeding 12.5 millimeters (IP20). Indeed, according to the same PUE, the fulfillment of this condition allows the installation of open electrical wiring in rooms at any height, but it should be taken into account that wiring of this type cannot be used on roofs, with the exception of the place where the cable enters the building.

Features and nuances of installing corrugated cables in the ground

Installation of cable and wire products in corrugated structures in the ground does not contradict the requirements of the PUE and profile SNiPs. It is important to choose the right material and diameter of the corrugated pipe, as well as take into account all the nuances of this part of the electrical installation work. Below is a list of features to consider:

• You should not use corrugation made of ordinary metal. It will quickly become unusable under the influence of corrosive forces (moisture, chemical compounds);

• Polymer PVC corrugation is a possible, but not ideal option. This material does not withstand temperature changes well enough, it can become brittle and begin to “crumble”;

• Corrugated HDPE is the best choice. Low-density polyethylene copes well with all the “challenges” of underground cable laying;

• it is necessary to take care of special protective cases that will be placed over the corrugation in rocky areas of the cable route, in areas with an increased likelihood of soil pushing and disruption of the integrity of the power line (roads and paths, near trees, in shallow trenches, near other pipelines). The cases are made from asbestos-cement pipes or modern plastic materials, including detachable ones in the form of a pair of half-cylinders;

• when laying the corrugation together with the cable, you must not pull it; there should be a slight slack or even a wavy laying;

• We must not forget about grounding the armor of protected cables and stretching the signal tape.

Types and differences

Pipes vary in material, purpose and color. Their color indicates the material of the product:

1. Grey. The polyvinyl chloride tube is fire-resistant and moisture-resistant. The possibility of fire from a short circuit is excluded. Well suited for installation inside a house or apartment, but not outside: it can quickly crack, as it is sensitive to ultraviolet radiation.

1. Blue. Made from self-extinguishing polypropylene. Its distinctive features: UV resistant (suitable for outdoor installation), can be used and installed at temperatures from -40˚C to 100˚C, easy to install due to its high elasticity.

1. Black and orange. One of the most common due to its affordable price, reliability and resistance to moisture is corrugated. The disadvantage of such products is that they support fire well: if the entire ceiling in the house consists of such pipes, the fire will easily spread to other rooms.

Hidden and open laying of wires in a corrugated pipe

Hidden electrical wiring in walls has its advantages, for example from an aesthetic point of view. In addition, the conductors are cooled better.

The disadvantages of this type of installation of power lines traditionally include:

- high labor intensity; — a large amount of construction waste; — increased likelihood of subsequent damage to the wires, for example, with a hammer drill; — a problem with installing hidden power lines in wooden buildings; — difficulty or impossibility of replacing electrical wires.

These problems are partially solved by pulling the cable into a corrugated cable and laying the pipe in prepared grooves or monolithic concrete.

It is easier to install open wiring in a corrugated pipe by making bends to lamps, sockets and switches. Flexible corrugation is excellent for laying even on uneven walls. The corrugated pipe is secured with special clips or ties.

Rules for installing corrugated cables in walls and ceilings

When laying corrugated cables along wall or ceiling surfaces, you must follow simple rules:

• cable power lines must be mounted in a horizontal or vertical plane;
• Mutual intersections of power lines should be avoided;
• power supply to switches is usually supplied from above, and to sockets from below;
• clips for mounting corrugations are secured using special anchors, screws or dowel nails;
• the distance between the corrugated pipe fastenings should not exceed 40 cm, otherwise the structure may sag;
• the joints of corrugated sections are formed by connecting couplings;
• the inter-wall passage of the corrugated route is made through a special sleeve and can be sealed;
• The rotation of the power line placed in a corrugated pipe is carried out to a radius the value of which is higher than permissible for the corresponding brand of cable product. It is important to remember that bends make future cable replacement more difficult;
• The corrugation must be secured to a suspended ceiling only on a concrete base.

Basic installation rules

To properly install the corrugation, you must adhere to the following procedure:

1. Using a tape measure, measure the required amount of pipe and cut it with a utility knife. There is a wire inside the pipe: you need to carefully cut it with side cutters while holding it. If the wire has sunk into the corrugation, the broach can only be retrieved by cutting the corrugation to the required length.
2. Connect the cable to the end of the wire. You need to bend the string with a hook and pierce the edge of the insulation, or wrap it around the cable several times.
   

   The connection point must be insulated, otherwise the protrusions will cling when pulling the conductor.

3. Secure the free end of the broach. If two people are involved in the installation, one of them just needs to hold the wire. During independent electrical installation, the broach can be fixed to any stationary object: a door handle or a battery. The purpose of fastening is to create tension, which will later allow the wire to be pulled through.
4. The last step is to fully tighten the wire inward. This must be done carefully, since if the tension is too strong, it will break and the work will have to start all over again. If the cable can be tightened, the corrugation can be secured with clips.

How to quickly pull a cable into a corrugation? — Recommendations, video

In order to quickly pull wires into the corrugation, you will need a certain skill. This procedure itself is not difficult if you follow the instructions:

cut the corrugated pipe to the required length. Be careful not to damage the wire inside - it will be needed later;

twist the end of this wire (“conductor”) with the cable/wire;

insulate the joint for smoother pulling;

create tension in the corrugation, for example, by securing the second free end of the “conductor” to the door handle or battery;

pull so that the conductor gradually, without jerking or catching, enters the corrugation.

The entire algorithm for pulling the cable into the corrugation is clearly shown in the video.

How to stretch a wire into a corrugation with your own hands

Expert builder Viktor Petrovich says:

Now we will tell you and show you how to correctly route the wire into the corrugation using a conductor. That is, we will have a special wire running in the corrugation, and one end of the wire will cling to this conductor, to the wire, and we will tie one end of the conductor to some kind of anchor, for example, to a pipe or a metal rod.

In our specific example, we will use a stud that is directly embedded in the wall. It holds well in the wall, and, accordingly, we will fasten the conductor at one end and pull the wire into the corrugation.

Attach the wire to a stud in the wall

At the same time, you should not tie the wire to the pipe, since, for example, in this case we have a polypropylene pipe, and it can be damaged. It is better to use a metal element attached to the pipe - a clamp pin. You also need to first straighten the corrugation well so that there are no bends in it, and so that the wire passes well inside it.

Then we take the wire and strip it. We make a puncture at one end of it (pierce a hole with a wire), pull the wire through it, and then twist it there. We bite off the twisted end of the wire with a tool so that it does not interfere with the movement of the wire in the corrugation. At the next stage of work, we wrap this place with electrical tape. For what? So that the wire also slides well in our corrugation, and so that its corners do not cling to the stiffening ribs.

We drag the wire through the corrugation

You can say a few words about electrical tape. It turns out that in this particular apartment we will have three wires - phase, neutral and ground. And now, just now, we use electrical tape of a color that directly indicates that our wire is earthen, that is, its color is green-yellow with stripes.

After we have wrapped the end of the wire with electrical tape, we insert it into the corrugation and pull it there with the help of a conductor. In this case, the corrugation needs to be pulled out so that it is straight. That is, the wire with the corrugation is stretched, and the wire is pushed inside the corrugation until our end of the wire wrapped with electrical tape appears.

On one side of the corrugation a wire appeared, wrapped in electrical tape.

As soon as its end has appeared, then everything is done: the wire is in the corrugation, its end is stripped and protected with electrical tape, so you can safely lay it and seal it in the place where it is needed.

Is it possible to lay wiring without corrugation?

For every property owner, sooner or later there comes a time when he needs to decide which electrical wiring will be most optimal in his building. Someone decides to spend an unreasonably large amount of money on installing cables in a corrugated pipe, thereby enriching the contractor. Some people, in order to save money, decide to ignore regulations, putting people’s lives in danger, and install electrical wiring without corrugation. Let's try to understand all the nuances and find out: what kind of wiring should be in the room and how to make it safe without spending extra money.

• Is corrugation necessary?
• Cases of justified use of corrugation
• Cable laying without corrugation
• Open installation method
• Hidden electrical wiring in the walls
• Conclusion

Corrugation classification

Corrugated hoses are distinguished according to the following characteristics:

• material of manufacture (see above);
• color and type of corrugation;
• fire-fighting qualities:
• sizes.

Color and type of corrugation

Corrugated pipe

The coloring of corrugated products complies with international standards. The color of the corrugated pipe determines its scope of application.

Color code chart for corrugated hoses

Note! Electrical engineers use color coding not only in connection with the scope of application. Multi-colored corrugation indicates cables leading to certain consumers. At the same time, the fire-fighting qualities of one or another type of corrugated hose are often neglected.

Color and type of corrugation

Fire properties

Of all the materials from which corrugation is made, only products made from high-density polyethylene are flammable. Other polymer pipes have self-extinguishing properties. That is, when the source of open fire ceases to affect the pipeline, the corrugation stops burning. The metal hose can only melt if the fire is not put out in time.

The fire resistance of corrugation can also be determined by its color. The most dangerous are black and orange (red) sleeves. They support combustion very well. You can imagine the danger posed by electrical wiring enclosed in such corrugation behind a suspended ceiling, or when wires are laid in a corrugated hose along wooden walls, instead of enclosing them in steel pipes.

Fastening the corrugation with ties to the suspended ceiling frame

In areas where there is a risk of fire, only gray hoses should be used. After all, if only one pipe catches fire, the whole house will be engulfed in fire.

Dimensions

The difference between the outer and inner diameters determines the thickness of the corrugation wall, which significantly affects the load-bearing capacity of the product. The table provides information on the sizes of corrugated pipes for electrical wiring.

Table of sizes of polymer corrugated pipes

Cases of justified use of corrugation

In places where the wiring may be subject to mechanical damage, the cable is installed in a corrugated pipe.

It is used practically without restrictions in low-current systems:

• in signaling,
• in cable television,
• in telephone lines,
• on the Internet.

You should not do without corrugation when laying cables in a floor screed.

If the supply lines are placed under plasterboard or suspended ceilings, then it is more convenient to use a corrugated pipe. Then the wiring changeability requirement given in Chapter 7.1 will be met. clause 7.1.37. PUE, and additional mechanical protection of the power line will be provided.

Why do you need corrugated wires?

Today, most often, corrugation for electrical wiring is used from PVC material or metal.

This will solve several issues at once:

1. The wires will not be deformed.
2. Protection from all external precipitation will be provided.

Such a part is important for protection against electric current, for example, during construction work.

Note! When building a house, the wiring is laid with special care, since any building shrinks. Corrugated pipe for electrical wiring acts as an additional protection factor

In what cases can corrugation not be used?

In cases where the design is not a strictly required part of the electrical wiring. There are cases when the cable is installed in grooves, after which plastering is carried out.

The design also does not occur if the electrical wire is pulled while external insulation work is being carried out.

Note! The wire is designed to withstand cold and humidity and has an increased level of strength.

Methods for protection

It is mandatory to use corrugated cables for wiring inside a wooden structure.

So:

1. In some cases, the structure is replaced with PVC cable. But in terms of safety it is inferior to corrugated. At the same time, the cable is resistant to complex mechanical damage.
2. For attic structures, it is best to use corrugated material or durable pipe.
3. A cable is used for new wiring if there are no plans to renovate the premises.
4. In a residential area, such a wire will not look beautiful due to its unaesthetic appearance.

Note! You can also do without corrugation in cases where reliable fixation and quality of insulation are ensured.

Cable laying without corrugation

Electrical wiring in a home can be installed in several ways, depending on:

• cable type;
• the environment in which the wiring is planned;
• base material on which installation work will be carried out.

Cable laying without corrugation can be done in an open or hidden way.

Open installation method

When installing power cables on combustible structures or in places where it is difficult to make grooves, open wiring is used. It is laid over the walls and along the ceiling with a finished finish.

Fastening is carried out with brackets (clamps) at least every 40-50 cm, and in places of bending, 10 cm on each side of the bending point. The fastening frequency should be such that the cable does not sag.

This installation method is used mainly in basements, utility rooms, and garages. It is also possible to install wiring in residential premises on walls and ceilings without corrugation, if the cable has a fireproof sheath.

Open wiring in retro style in wooden houses is performed with single-core conductors twisted together, attached to the surface of the walls (ceilings) using porcelain insulators. There may be two or three wires, depending on whether there is grounding in the house.

In the manufacture of modern retro cables, copper wires with a cross-section of 0.75-2.5 square meters are used. mm. First, they are covered with a layer of PVC, after which there is decorative insulation made of silk impregnated with a composition that does not support combustion. Fiberglass covering may be used.

Installation in a metal pipe is one of the most labor-intensive, expensive and at the same time reliable methods of open wiring. Most often used:

• in fire and explosive areas;
• when passing through ceilings and walls;
• for inputs into cable kiosks;
• for outdoor installation;
• in wooden houses, baths, etc.

Metal pipes reliably protect communication networks from mechanical damage and aggressive environments. In addition, open wiring in metal pipes can be an interesting design solution when decorating a room.

Hidden electrical wiring in the walls

To give the room the most aesthetic appearance, hidden electrical wiring is used. The cables are hidden in the wall (ceiling) material, hidden under a layer of plaster.

The cable is laid in grooves - specially cut grooves, the width of which must correspond to the thickness of the conductor. Obviously, it is better to do without corrugation here, since making furrows for it is much more difficult.

It is more convenient to install electricity before finishing work, then you can do without gating. First, the wires are fixed, and then the walls are plastered.

Before installation work, markings are made for the future electrical system of the apartment. Mark the installation locations of sockets, switches, junction boxes, and wiring lines.

Then they start cutting the grooves. To do this, you can use a hammer drill, wall chaser, grinder with a diamond blade, or impact drill.

After the places for sockets, switches, junction boxes and grooves for laying cables are ready, installation of the electrical network begins.

When is corrugation used?

Firstly, the corrugation will allow the cable to be laid inside structures. According to the rules, if the building material is combustible, it is necessary to fence off hidden wiring. The role will be played, for example, by aluminum corrugation. Next, select the text relevant to the situation:

Shared lines

In mechanically strong hoses it is allowed to lay together lines for the following purposes:

1. Power circuits of one unit.
2. Power and control circuits of technologically interconnected equipment.
3. A circuit that powers complex lamps (a chandelier with two keys).
4. Single-purpose lighting lines (emergency, main), provided that the number of wires is less than 8. The total cross-section, including insulation, does not exceed 35% of the internal diameter of the corrugation.
   Wiring replaceability and maintainability are ensured. The corrugations go between the distribution boxes. The connection points are accessible to visitors. Corrugated is unable to provide opportunities. Corrugation, tubes
5. Lighting circuits up to and above 42 volts, which are prohibited from being laid together. The low-voltage part is additionally insulated with a pipe. Circuits up to and above 42 volts may be laid in one sleeve, provided there is a partition with a fire resistance of at least 0.25 hours (15 minutes).

Cross-section of conductor and ground electrode

The smallest conductor cross-section is selected according to table 2.1.1 PUE 6 (https://files.stroyinf.ru/Data1/42/42611/index.htm#i42831785). The diameter of the core depends on the purpose of the wire.

Grounding conductors, regardless of the installation location, provide a certain minimum cross-section. For a rectangular shape, 48 square millimeters in steel with a thickness of at least 4 mm. Round potential equalization lines can be made using wire rod with a diameter greater than 6 mm. The minimum cross-sections of aluminum, copper zero-working, grounding conductors are, respectively, 2.5, 1 square millimeter. For individual insulated wires, the parameters are 2.5 and 1.5, for non-insulated wires - 6 and 4. Let us recall that the cross-section for copper and aluminum of the main grounding line going to the circuit is 6, 10 square millimeters.

One channel - several wires

It is prohibited to lay main and backup cable lines, working and emergency lighting cores in one channel. The phase and neutral working wires are laid in one pipe.

Forming connections

Electrical connections of wires are formed through terminal blocks, soldering, welding, and crimping. Note that twists do not appear. The laying of corrugated pipes in the walls is designed to ensure the replaceability of wiring. Wire connections are available for inspection and repair. Use junction boxes.

Corrugation plexus

Combustible and non-combustible base

A fireproof corrugation is laid along the combustible base in the form of open wiring. Concealed installation in a groove (cutout) is allowed. The corrugation is fireproof, or a gasket is installed to separate it from the base. The top can be sealed with plaster.

Plastic corrugation can be placed in the grooves of concrete and brick walls to form channels (needed to change electrical wiring). With subsequent finishing with plaster and other fireproof materials. If necessary, if you want to use lining, read above - lay it with fireproof material. To avoid breaking your brain, use Penofol. Easily withstands the pressure of a gas burner. External laying of the cable along the walls in plastic corrugation on fireproof bases is allowed.

When laying corrugation along a fireproof wall along the route, it must be at least 10 cm away from combustible areas. If they are unable to provide this, use a separating layer at least 10 mm thick: plaster, alabaster, cement.

Protective functions

The metal corrugation is connected to the building's potential equalization system, which goes to the grounding circuit of the lightning rod. At the same time, the step will provide protection against radiation outside the 50 Hz industrial frequency.

The metal corrugation is protected against corrosion according to environmental conditions.

The corrugation is laid to avoid moisture accumulation. The housings of distribution boxes and panels are equipped with cable entries. Conical ones are equipped with expanding sectors. The diameter increases starting from the top. By trimming, we achieve the desired size. The junction of the corrugation and the junction box is impermeable to moisture. If necessary, add adhesive sealant around the cut perimeter.

Posting planning

Using this method, power cables are laid along the walls of buildings from the outside, from the inside. If the requirement is ignored, a small amount of liquid may cause the system to fail. Applies to communication systems where signals are weak. If you take power wires, liquid entering a phase will certainly cause a complete failure of the line.

Note that the broken corrugation needs to be repaired. Hooligans have many opportunities to ruin an electrician's life. How to repair? The plastic one can be sealed (if you have the skills) with polyethylene, the metal one can be sealed with a special acid. Increased attention is paid to rooms with high steam levels.

Metal corrugation

It is sometimes prohibited to use metal corrugation. In bathrooms and toilets, the use of metal corrugation is limited. It is allowed to be placed under the floor surface, covered with a grounding mesh. Applies to metal screens and cable armor.

In other places the aluminum corrugation is grounded. The resistance up to the bus output point does not exceed 10 ohms. It is measured by a tester (if you have the skills) or a special device.

Open wiring

When laying open, the distance from the corrugation to the combustible base is 10 mm. If the condition cannot be met, re-use gaskets (for example, Penofol). Should protrude 10 mm away from the corrugation border.

According to the regulations, unprotected open wiring is carried out at a height of at least two meters from the floor (surface, ground). The condition can be radically changed by using corrugation with a degree of protection of at least IP20 (against penetrating objects with a diameter of more than 12.5 mm). You don't have to choose. Any corrugation fits the definition. Of course, at the same time we will fulfill the requirements according to which the cable is laid along the wall of the building.

Laying open wiring on roofs is prohibited. With the exception of building entry points.

How to lay the cable

We firmly believe: the PUE was written by sensible people. They are well familiar with Russian realities, they left few loopholes in the theses, and closed those contained in other documents. Switchboards cannot be installed in bathrooms. Obvious fact? Find information in standards and building regulations. It turns out that an apartment switchboard can be installed in zone 3 (classification GOST 50571.11). Let's start the search by examining PUE 6, although the collection of rules is completely deprived of legal force.

It’s not the law that’s important; we want to build a house. We begin the classification of the installation method by determining whether the wiring is hidden or open. It's easy to distinguish. Hidden electrical wiring is hidden by elements that are a structural part of buildings. If you put the corrugation in plain sight, there will be exposed electrical wiring. Although the insulation of the wire is not visible, no one outside will be able to tell what is inside. A similar corrugation will take on a different meaning when laid under the floor. Hidden electrical wiring.

Hidden point: PUE operate with the concept of a protected wire. There are references to GOST, we know (we saw it on the Internet), the definitions are misinterpreted. One forum provides a link to the GOST 15845 standard. Complaints follow, saying that it is not clear how open cable laying along the wall is carried out, the distinction is made on the basis of security. There is no such thing among the definitions. Each cable and wire is equipped with GOST, TU, act according to the text.

SIP refers to GOST R 52373. The standard indicates: protected wire. What and how is the tenth question. The PUE follows the vocabulary, referring to GOST. SIP installation is carried out like a protected wire. We emphasize again - the term defines the structure of the cable, alien to boxes, sleeves (corrugations).

Lay corrugation along the wall and floor

Many people are probably interested in how corrugated pipes are connected to distribution boxes. We weren’t going to get away with general phrases, listen!

• Individual pieces of corrugation are joined using couplings (price is about three rubles per piece). Use the products offered by the manufacturer. There are many ways to connect the coupling and corrugation. If there are no cable connections in a given area of ​​the site, it is possible to seal the joints with sealant.
• There is a steel broach inside the expensive corrugated models. Pipes for laying wiring in the apartment are used as efficiently as possible: a channel is made in the wall (on the surface), and according to the electrical diagram, the required number of wires is pulled inside.
• The corrugation is attached to the wall with specially shaped anchors. Installation on brackets made of metal packaging tape, which is pressed onto dowel-nails, is allowed.
• As for the accumulation of water inside the corrugation, the forums are full of the topic. The legislative part of PUE 6, which we are considering today, has not been adopted. If you are building for yourself, it is more important to feel confident in the quality than to comply with the letter of the law. In dry rooms, it is allowed to use corrugated joints without compaction or sealing.
• The cable is laid through a corrugated wall through a special sleeve, selected in diameter. The passage is sealed if necessary.

• The turn is performed by bending the route with a radius higher than that allowed for the bundle cable brands. Similar parameters are often indicated for corrugation. Please note that if it is necessary to replace part of the cores, problems may arise. When rounding the corrugation, be careful not to bend it. Otherwise, the requirement for filling the section (35%) will be violated.
• In the attic, the height of the cable on the wall is not standardized when using any corrugation. However, the requirements listed above are met.

Indoors, it is practiced to lay cable ducts along the walls, because the technique looks elegant. And in basements and attics, corrugation is appropriate due to its excellent insulating properties.

How to fasten the wire in the groove

After the preparatory work, you will need to think about how to securely fasten the wire laid in the groove. There are several methods.

Alabaster

Preparing the wire for fastening with alabaster
Construction gypsum mixture is used if it is necessary to fix the wiring in the grooves. Alabaster will hold up well to a minimal amount of soft-insulated cables. The composition is applied in small portions. The disadvantage of this method is that the mixture sets quickly, so it cannot be prepared in large volumes.

Dowel clamps

Dowel clamps
Products are available in black and white colors for cable diameters of 19-15 mm, 5-10 mm and 11-18 mm. The polyamide fastener is 6 mm in diameter and is a loop with clamps at the lower ends. Before using dowel clamps, you will need to make a groove with a hammer drill, install fasteners and secure the wiring. The disadvantage of the technology is the strict selection of the cable diameter to the size of the dowel clamps.

Dowel-ties

The product looks like a dowel-nail combined with a cable tie, and is made from self-extinguishing plastic compounds. Dowel ties are equipped with detachable and permanent locks. In the first case, the master can add or remove wires. Used for open and hidden installation of a single or bundled cable line on brick, concrete and other surfaces.

To attach the wire with a dowel tie, you will need to place a tie in the drilled grooves and secure it with an expanding peg. The cable is laid in the open product. The tie is pressed.

Dowel clips

Suitable for open laying of communications on drywall or when performing retro finishing. The fastener is a curved plastic strip with elastic branches at the ends. These elements hold the latch. The clips are suitable for mounting a flat or round conductor with a small cross-section (television, telephone, Internet connection).

Installing the dowel clip is easy. You will need to drill a niche of the required diameter, insert a tourniquet into the clip, tucking its ends into the hole. The element is inserted into the hole with force. Electrical communications look neat and do not interfere with operation.

Cable ties for dowels

Cable tie for dowel
Modifications in the form of a dowel with threads and a tie plate. An element made of non-flammable plastic compound or nylon is easy to attach to aerated concrete, wooden, brick or concrete walls. Compatible with screws, screws, self-tapping screws, standard and dowel nails.

Before installation, it is necessary to make a hole to match the diameter of the fastener. First, a dowel is placed, then the cavity in the screed and the base are aligned. Then the tie-plate is hammered and screwed, and the wires are laid on the finished route.

Plastic dowel for screed

Plastic dowel for the tie
Polyamide dowels for the tie with a rectangular head-hole allow you to fix the wire without any problems. You will need to hammer the element in and then pull the wire through the head. It will be securely and firmly fixed in the groove.

Aluminum plates

Most often, cut strips of thin metal are used. Several cables are wrapped around a plate, which is then drilled through and attached to the bottom of the groove with dowel nails.

The strip is punched exclusively in the center, and the cable strips are laid on top of it. After placing the wiring, the ends of the box are bent.

Fasteners for organizing a bundle of conductors

Cable routes made on the basis of a vertical metal tray
Not all types of wires are fixed permanently. Problems arise when equipping a workplace where it is necessary to install lighting, internet, and connect a PC. Special wire holders eliminate holes from nails and screws and allow you to quickly move communications. There are several types:

• Cable clip with double-sided adhesive tape on the back. Suitable for installing wires on furniture or plastic panels.
• Installation site. To fix the wire, first secure the pad with the adhesive part. The bundle is attached to the holes with a standard tie.
• Cable trays. Made from galvanized wire or perforated metal. Used if you need to fix wires to the ceiling.

Trays can be used in contact with flammable materials.

Homemade devices

Homemade devices for fastening wires
If specialized fasteners are not at hand, home craftsmen use improvised material:

• Dowels or nails. Fastening is carried out before laying the wires. Using a dowel or nail, punch a piece of telephone cable in the center and screw another one.
• Corrugated hose. You will need a piece longer than the width of the shtrof. The corrugated hose is slightly compressed and placed in the groove. Fasteners can be removed as the plaster layer is applied.
• Perforated strips. The technology is suitable for Khrushchev-era buildings and involves fixing perforated sections with dowels across the pipe. In this way you can attach bundles of wires.
• Staples made of galvanized sheets. The material must be cut into strips 1 cm thick and the staples bent. The products are suitable for fastening cables to walls and ceilings. They are located in increments of 50-80 cm and are secured with nails.

Homemade fasteners are easy to manufacture, allow you to save money on the purchase of special consumables, can be installed many times, and securely fix a single wire and a bundle.

Is corrugation needed when laying cables?

Some people confuse the concepts of wire and cable. Let's first take a moment to clarify this issue. A wire is a core with insulation, and a cable is several such wires with additional insulation. Many people ask whether corrugation is needed when laying cables? The answer to this question is given by the PUE.

The PUE has its own requirements for both cable and wire. It is logical to conclude that the requirements for a conductor with additional insulation should be softer and in most cases, it does not need corrugation. On the contrary, the installation of wires must be approached more seriously. Here corrugation is almost mandatory. In this article we will take a closer look at the moments when laying a cable in a corrugated cable is necessary and when it is not.

Dowel-ties

A dowel-tie is actually a combination of two types of fasteners - a dowel-nail and a cable tie for the dowel. In fact, this is an analogue of a facade dowel, only with reduced dimensions. They are very convenient to use. A dowel tie is inserted into the pre-drilled holes and secured by driving in an expansion peg. The fastener is ready to “accept” the wire and fix it with a tie. Convenient for both bundles and single cables.

Read also: What is the difference between an alcohol meter and a hydrometer?

In what cases is corrugation needed and in what cases is it not?

If you plan to use a cable with fire protection (for example, VVGng-LS 3x1.5 flat), then in most cases corrugation is not needed. However, there are exceptions. If the conductor needs to be laid in the ground or there is a possibility of damage, then corrugation is required. For example, when pouring a concrete screed, or when it is planned to replace it in the future. Just note that in this situation, PVC corrugation will not work. The metal version in this case will be more appropriate. There are no restrictions on the use of a protective tube when laying telephone lines, Internet lines, etc. Laying several cables in one corrugation according to the rules of the Electrical Installation Code is allowed, in particular, group lighting lines and sockets. However, it is worth remembering that if a failed conductor is replaced, this task can become difficult and unsafe.

When installing internal wiring (not cable), corrugation is required. In such cases, the cable can be placed in a corrugation if there is a possibility of its replacement. However, such a conductor must be flexible and the protective tube is selected 1 size larger. The PUE states that when installing power cables in frame or wooden structures, the use of corrugation is strictly prohibited. Also, if the cable is planned to be laid in a wall, under the floor or baseboard, there is no need to use corrugation. According to the PUE, the requirements for the corrugation are much stricter than for the cable itself. For internal wiring, there must be at least 10 cm of plaster or other fireproof material around such a protective tube. There are no such conditions for cable installation.

Wire connection methods

There are several methods for connecting electrical wires. You can choose the most convenient and suitable option for your case.

Prices for cables and wires for construction and repair

Cables and wires for construction and repair

Twist

Twisting
Currently, connecting cables in junction boxes using the twisting method is prohibited - it is considered extremely unreliable compared to other existing options. By choosing twisting, you consciously accept all possible responsibility upon yourself.

How to properly splice and branch wires using twisting

The connection itself is extremely simple: approximately 10 mm of insulation is removed from the wires, and then they are carefully screwed onto each other. When connecting wires with a diameter of up to 1 mm, we perform at least 5 turns, in the case of twisting more “serious” cables - from 3 turns.

Crimping

Crimping tool
Popular connection option. It is performed using a special sleeve according to the size of the wire bundle. The sleeve material must also match the cable material.

To crimp the product, press pliers are used to crimp the sleeves. Craftsmen often try to perform crimping using pliers, but professionals recommend refraining from this option, because the connection will not be as reliable.

The work is performed in the following order.

First step

We remove the insulation from the wires, focusing on the length of the sleeve used.

Second step

We twist the wires into a bundle and insert them into the connector.

Third step

We crimp the sleeve with the wires using press pliers.

Crimping process

Fourth step

We insulate the finished connection with heat shrink or regular electrical tape.

Crimping process

Welding

Welding
After making such a connection, what is essentially a solid wire is obtained, which is not afraid of either oxidation processes or other negative effects characteristic of detachable methods.

To connect wires using the welding method, you need to prepare the following:

• 24V welding machine with power from 1 kW;
• flux;
• carbon electrode;
• protective equipment (gloves, mask/goggles).

  
  Wire welding diagram

We work in this order.

First step

We remove the insulation from the cables and strip the conductors until they shine. To do this we use sandpaper.

Second step

We connect the wires using the twisting method.

Third step

We pour flux into the recess of our electrode.

Fourth step

Apparatus for welding strands TS 700 2
Turn on the welding machine, press the electrode against the cables and hold until a ball forms - the so-called. "contact point".

Fifth step

Welding
We clean the resulting contact point from flux and coat it with varnish.

Finally, all we have to do is insulate the finished connection.

Soldering

Soldering
The procedure remains the same as when connecting wires by welding. The only difference is that the cables are connected using solder melted with a soldering iron. The molten solder should flow into the twist.

Important note! The connection is very reliable and durable, but professionals recommend refraining from using it in places where the cables can get very hot.

It is also not recommended to use soldering in areas of possible mechanical stress on the connection.

Screw terminals

Screw Terminals
An excellent method for quickly and easily connecting wires in a junction box. Compact, inexpensive clamps allow you to connect both homogeneous and dissimilar conductors.

The job is done in two simple steps. You need to do the following:

• strip off approximately 5 mm of insulation from the ends of the wires;
• insert the wires into the clamp and tighten with a screw.

Important! Control the clamping force so as not to damage the integrity of the cores. Be especially careful when connecting aluminum wires.

Bolted connections

Bolted connections Termination of wires
The connection is reliable, but very cumbersome. Suitable for the same bulky old-style boxes. In a modern box, a bolted connection may simply not fit.

The work is performed in the following order.

First step

We put a steel washer on the bolt.

Second step

We put one of the wires to be connected on top of the bolt. First you need to peel off the insulation and form a ring from the cable. We do the same with the second wire in advance.

Third step

We put on the next steel washer.

Fourth step

We put on the ring of the second wire.

Fifth step

We put on the last washer and tighten the connection with a nut.

Of course, a bolted connection also needs insulation, which will not have the best effect on its dimensions.

Methodology for using RCD

We compare according to various criteria which is better, a difavtomat or an RCD, in our new article.

Self-clamping connections

The most modern and popular option today. The clamps are extremely easy to use. In addition, such connections initially contain a paste that eliminates the risk of metal oxidation, which allows dissimilar conductors to be inserted into the clips without any fear.

We work in this order.

Self-clamping connections

First step. We remove approximately 10 mm of insulation from each wire.

Second step. Raise the clip lever up.

Third step. Insert the conductors into the connector.

Fourth step. We lower the lever down.

Clamps without levers simply snap into place.

Self-clamping connections

Corrugation for laying cables in the ground

During installation work on laying cables in the ground, protective cases are used, such as a metal hose or HDPE corrugation. The latest version of the tube has the following properties:

1. elasticity;
2. high strength;
3. the ability to restore its original size.

Using this method of laying, when compared with external laying, has enormous advantages, namely:

• weather protection;
• mechanical;
• chemical

Metal corrugation is also suitable for these purposes, but its price will be approximately 2 times higher. But the service life of such a metal hose will be longer.

Corrugation for underground cable installation should not have magnetic properties. It is worth knowing that the diameter of the protective tube directly depends on the length of the cable. So, for example, if the conductor is up to 5 meters, then it can be placed in a 50mm corrugation. If the length is more than 5 meters, then the protective tube must be at least 100mm in diameter. We draw the attention of interested parties that HDPE corrugated cable in Moscow costs between 7-36 rubles per meter, depending on its diameter.

Analysis of common mistakes when laying underground corrugation

The following are common incorrect practices:

1. Construction of a line from SIP wire. It is designed for laying by air; in the ground, due to the lack of armor and intolerance to condensation, it quickly fails.
2. Assembling a casing for a power line from several fragments. Such cables are especially sensitive to moisture, so they need the most sealed corrugation.
3. Using copper cable with a core cross-section of 6 square meters. mm or aluminum 10 sq. mm. Even if such a conductor is suitable for the load, its use is contrary to regulatory requirements: the minimum cross-section is 10 square meters. mm for copper cable and 16 for aluminum.
4. Placing the conductor near the foundation. It is necessary not only to maintain a distance of 60 cm, but also to extend the cable beyond the line drawn from the base of the foundation at an angle of 45°.
5. The conductor is located close to the ground loop. These are often installed in the same trench to save labor and time. The minimum distance is 30–35 cm.

Another common mistake is laying the cable directly on the ground, without an underlying sand cushion. Under such conditions, the corrugation is likely to be damaged by sharp stones and other debris. In the absence of sand, carefully sift the soil.

Corrugation for external cable laying

To lay the power cable outside, the following types of protective pipes will be appropriate:

1. HDPE;
2. polypropylene;
3. metal hose

Let's look at them in a little more detail. The first option is the cheapest of the above. Resistant to sun and low temperatures. The next corrugation for outdoor cable laying costs about 2 times more than the first, but its use is possible in small areas from the equipment to the highway. The latter option has a long service life. Also well suited for laying near the ground, where there is a risk of cable damage by rodents.

Studying the box wiring diagram

When connecting wires in a junction box, it is very important to know the specific markings of each cable. This will create a secure, reliable and generally correct connection.

Let's study the wiring diagram of the box. Connecting wires with grounding (PE)

Connecting wires without grounding (PE)

So, the “zero” wires (in the diagram they are blue) and the ground cables (indicated in yellow) are connected accordingly by color, as shown in the image. When arranging two-wire wiring, the circuit remains the same, only the grounding wires are excluded.

The phase desoldering procedure (indicated in black or red) is more complex. If only cables are routed through the box to connect the socket, the phase wires are also connected together.

Scheme in a junction box, two lamps

If cables go from the box to a switch with one button, then the wire that goes to the switch must be twisted with all the wires of the phase. The same cable that comes from the switch is connected to the phase wire going to the lighting fixture. As a result, 4 connections will be made.

Scheme in a junction box, two lamps and a group of sockets

In the case of connection through a junction box of a switch with two keys in conditions of three-wire wiring, a cable with four cores is connected to the chandelier. If the wiring is two-wire, the number of wires is reduced to three, because grounding is excluded from the circuit, as shown in the figure.

Studying the box wiring diagram

Without taking into account the separate twisting of the ground electrode, 4 connections are created in the box. All the “zero” wires (indicated in blue) are connected to each other.

The phases of the sockets and the power cable are twisted together and then connected to the common terminal of the switch with two keys. From the latter there are 2 separate wires going to the lighting fixture.

Thus, there is nothing super complicated about wiring the box. You just need to understand the peculiarities of the wire designation and the order of their connection. After this, you can begin to consolidate the acquired theoretical knowledge in practice.

Proper connection of wires in the junction box

Prices for distribution boxes

Distribution boxes