HDPE for laying cables in the ground. Why do you need a pipe for laying cables in the ground, technical specifications

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And electrical wiring inside the house requires additional insulation, which will protect the cable from external influences, and residents from electric shock if its insulating layer is damaged. HDPE cable pipe copes well with this task. In this article I will talk about the features of these products, existing varieties And in different ways styling

Permissible operating temperature is from -25 ºС to +70 ºС.
The permissible installation temperature is not lower than -30 ºС.
The density of polyethylene is 0.949–0.953 g/cm3.
Flammability class - B1, B2.
Nominal pressure depending on the type of pipes:
light - 0.25 MPa;
medium-light - 0.4 MPa;
average - 0.6 MPa;
heavy - 1 MPa.
Coefficient thermal expansion- 0.15–0.2 mm/mºK.
The brittleness temperature is from –70 ºС.

Areas of application

HDPE pipes are used as protective sleeves for cables laid in open, hidden and semi-hidden ways when installing:

power supply networks;
telephone lines;
telecommunications;
video surveillance;
computer networks;
fire, control, emergency alarms.

Reasons for high popularity

By doing electrical installation work HDPE pipe is very popular for a number of reasons:

She provides reliable protection cables, virtually eliminating the risk of electric shock if the cable insulation is damaged.
It has special design, facilitating the pulling of cables of all types.
HDPE pipe products, unlike metal boxes, are more convenient to transport and are absolutely not susceptible to corrosion.
Does not conduct electricity, therefore does not require additional costs for cathodic protection.

Life time

The service life of HDPE pipes for cable is at least 50 years.

Requirements and Standards

The requirements for the technical characteristics of cable ducts made of HDPE pipes are regulated by GOST 32126.1–2013. Recycled material grades must comply with:

GOST 16338-85. The standard applies to polyethylene low pressure the following brands: 271, 273, 276, 277, 286.
GOST 16337-85. Defines technical requirements to polyethylene high pressure grades 10803-020, 15303-003, 15803-020, 16803-170.

The outer surface of the HDPE technical pipe must be smooth, without noticeable peeling, cracks, chips and bubbles. The internal surfaces of the products should not have bumps or protrusions that would prevent the wire from being pulled through.

Polyethylene pipes are sold in lengths of 5–12 meters or in coils of 25, 50, 100, 200 meters.

Marking

Marking is applied by the manufacturer with outside HDPE pipes along the entire length in increments of 1 meter. It consists of the following notations:

manufacturer's name (trademark);
brands of polyethylene (for example, PE-63, PE-80);
SDR indicator (ratio outer diameter product to wall thickness). It determines the level of ring strength;
geometric parameters: diameter and wall thickness;
production standard (GOST or TU);
purpose of the product (technical, drinking, gas or sewer);
production dates.

Here is an example of a typical marking: PE63 SDR 11 - 40*2 technical GOST 16338-85.

Classification of HDPE pipes for cable laying

Manufacturers offer HDPE pipes for installation of cable ducts in two versions:

smooth;

These types pipe products differ in technical characteristics and are used for operation in different conditions.

Smooth

Smooth HDPE pipes are black, rigid, and have a high mechanical strength. They are:

Non-reinforced walls with a single-layer structure. Used for laying cables in brick walls, concrete structures, floor screeds.
Double-layer reinforced. Used for operation in more difficult conditions.

For turns, transitions in cable ducts from smooth pipes HDPE uses special fittings.

Corrugated

Polyethylene corrugated pipes are used for the installation of both surface and underground communications. They have a two-layer wall, in which the inner layer is smooth, made of LDPE, and the outer corrugated one is made of HDPE. Can be supplied with or without an internal probe.

Based on their ability to withstand external pressure they are divided into:

easy;
average;
heavy look.

Depending on the purpose they are painted in different colors:

red - for high-voltage routes;
blue - for laying communication lines and telecommunications;
black - general purpose products.

HDPE corrugated pipes are distinguished by excellent flexibility, can withstand heavy loads, and therefore can be used for laying curved mains and placed at different depths.

Advantages and disadvantages

HDPE pipes for cable protection have the following advantages:

Light weight compared to metal hoses.
Good electrical insulating properties.
Resistant to chemicals.
High degree of wear resistance.
Ability to withstand prolonged contact with an aggressive environment.
Low thermal conductivity, due to which condensation does not form.
Frost resistance. Pipes do not collapse when water freezes in them.
Affordable price. For electrical work, pipes made from recycled materials are used, the cost of which is 30–50% lower than products made from primary polymer granules.
Elasticity. It can be bent in difficult areas without using shaped parts.
The smoothness of the inner walls makes it easy to pull the cable through.
Sufficient rigidity.
Bacteriological resistance.
Resistant to mechanical damage and vibration loads.
Low coefficient of linear expansion.
Resistance to temperature changes.

Disadvantages include the ability of HDPE pipes to support and spread combustion. Therefore, they must be embedded inside fire-resistant materials, such as concrete screed, cement mortar, or laid in the ground.

The following indicators should be the determining factors when choosing HDPE pipes for cable:

Bandwidth. The internal diameter of the pipe must correspond in size to the total cross-sectional area of the cables that are supposed to be inserted into its cavity. The range of polyethylene pipe products includes products with a diameter from 16 to 225 mm and a wall thickness from 2 to 30 mm. If you need to stretch 2 wires with a cross-sectional area of 5 mm² each, then a pipe with internal diameter 20 mm. For 3 cables with a total cross-section of 24 mm², the optimal diameter will be 30 mm.
Strength characteristics. To assess the strength level of a product, take the SDR value in the labeling. The lower it is, the stronger the pipe and can withstand greater loads.

Methods and rules for laying HDPE pipes

The technology for laying protective sleeves from HDPE pipes has features depending on the location of the cable and its operating conditions.

The general rules for all installation methods are as follows:

It is not recommended to lay cables of different networks in the cavity of one protective channel.
, this may lead to the formation of a crease.
The joints between the pipes must be sealed. You can connect individual products using compression couplings, press fittings or butt welding.
The length of the section between the boxes should not exceed 25 meters.
At open method When laying outside the building, black HDPE corrugation, resistant to ultraviolet radiation, should be used.
To ensure the drainage of condensate formed on external surfaces, the pipelines must have a slope directed towards the duct boxes. Moisture will collect in them.
When the channel is buried more than 2 meters into the soil, it is necessary to make a protective layer on top concrete screed 8–10 cm thick.

Laying pipes inside buildings

Installation of cable channels inside buildings is carried out in the following order:

Cable routing markings.
Punching grooves in the building envelope (if necessary).
Connecting individual HDPE pipes into a pipeline and fixing them. To fasten products to walls or ceilings, special holders with a latch are used; to the floor, metal brackets are used.
Sealing of the structure depending on the location of the channel and its diameter. To seal the walls, use plaster or other Decoration Materials. Pipelines laid in the floor are poured with concrete.
Cable pulling. Wire inside plastic pipeline should be positioned freely, without tension.

Laying outdoors in a trench

In many cases, underground installation electric cable preferable to air routes. In the ground it will be protected from precipitation, icing and gusts of wind, and will be inaccessible to thieves of non-ferrous metals.

The process of laying HDPE pipes for cables in the ground consists of the following steps:

marking the dimensions of the trench;
trench excavation and bottom leveling;
laying out pipes along the trench;
backfilling the base of the ditch with sand or soft soil 10 cm;
sequential laying of pipe sections with sealing of joints by resistance welding;
checking the integrity of the cable sheath and pulling it into the pipe cavity without tension;
backfilling the finished pipeline with soft soil or sand with a layer thickness of 10–15 cm;
backfilling the trench with soil.

So that the laid route can be found in the future, signal posts are placed above it. When installing cables underground, fittings cannot be used to connect parts of a polyethylene pipeline. They can break its tightness.

Trenchless method of laying in the ground

In cramped conditions of private courtyards or dachas, where it is not possible to dig a trench, a trenchless cable laying method is used. For this purpose they use special equipment, allowing you to drill the soil in a horizontal direction. Before starting work, you need to obtain a drilling permit and perform an analysis of the geological composition of the soil.

Cable laying using the trenchless method is carried out in the following sequence:

Drilling a pilot well. It is performed using a special tip attached to a flexible rod. It allows you to change direction when encountering natural obstacles in the ground. The tip is equipped with special cooling holes and a navigation device. This allows you to control the drilling trajectory and correct its direction.
Well expansion to required sizes. At this stage, the tip is replaced with an expander, which makes it possible to increase the diameter of the well to the design parameters;
Pipe laying. First, you need to insert a cable into the pipeline, and then attach the assembled structure to a special rod of the HDD installation, which will pull it through the well. To reduce the friction force when passing a line of communication through a horizontal channel, drilling fluid is used.

For cable is the undisputed leader in the field of protection power wiring, communication communications and optical cable. Properties such as smooth inner walls, flexibility and great service life make HDPE pipe optimal solution in any large projects.

HDPE technical pipe for cable. The optimum ratio of price and quality.

Technical HDPE pipes carry exclusively protective functions without special structural loads. Therefore, their production is made as cheap as possible through the use of recycled materials. However, this does not at all affect the quality: technical HDPE pipe for cable has proven its excellent reliability over decades of trouble-free service. Modern technologies ensure stability of the profile geometry along the entire length of the pipe, uniformity of wall thickness and density. The price of technical HDPE pipes is unattainable for analogues made from other materials.

Smooth technical HDPE pipe for cable - pulling without obstacles.

The HDPE material initially has a very useful quality for cable laying - smoothness. Due to the specific surface smoothness effect on the walls, the cable easily slides along the internal cavity of the pipe. No less convenience when pulling the cable is ensured by the absence of joints over a section of up to two hundred meters due to the length of the pipe. In fact, when a smooth technical HDPE pipe is used to protect the cable, any mechanical obstacle when pulling wires is eliminated.

HDPE technical pipes for laying cables in buildings and ground.

HDPE pipe has average resistance to ultraviolet radiation, which limits its outdoor use. To increase stability, black pigment is added to the composition, which extends service life in open spaces. But it is ideal for cabling indoors and closed ground. HDPE pipe is used for trench laying and laying using the trenchless soil puncture method. As a protective sheath for the cable, it is laid in monoliths during the construction of buildings and structures. HDPE technical pipes for cable laying can withstand various manifestations of static and dynamic loads over a wide range, temperature fluctuations, and exposure to most acids, alkalis, and organic compounds.

HDPE technical pipe for electrical wiring cable.

The dielectric properties of low-density polyethylene are used for the manufacture of electrical protective covers. HDPE technical pipe for cable is used when laying power cables with low and high voltage. The electrical strength of HDPE is comparable to that of mica, the best natural dielectric. Additional protection in case of cable insulation breakdown is provided by the fire resistance of the electrical pipe.

Technical HDPE polyethylene pipes for laying communication cables.

There are special technical conditions for laying communication lines, including optical lines. They involve the use of HDPE technical pipes. Simplicity of installation, the possibility of hermetic joining, low cost, physical and chemical properties, durability of at least half a century determine the advantage of technical polyethylene pipe HDPE for laying cables when choosing a protective sheath for communication lines.

Main technical characteristics of HDPE pipes for cable laying.

The main technical characteristics of the HDPE pipe for cable laying are the parameters that fix dimensions, physical, chemical and operational properties.

Based on the outer diameter and wall thickness, the SDR coefficient is derived, which determines the type of pipe - light, medium-light, medium, heavy.

Important control indicators are the density and the degree of tensile stress that determine the flexibility and elasticity of the pipe. The thermal conductivity of the material is directly related to the flammability class. For HDPE technical pipes this is class B1 or B2 (difficult to ignite and normally flammable).

Resistance to aggressive environments, low specific gravity, wide temperature Range, ease of installation and long service life have determined the popularity of HDPE pipes for electrical work. Our company sells any batches of pipes in Moscow and in the regions. In the catalog of our organization HDPE pipes different types, diameters and lengths. Wholesale deliveries and retail sales are possible.

HDPE pipes are designed to protect the power cable from external negative factors (mechanical, organic and chemical), as well as the effects of stray currents. Depending on the purpose of communication networks, the technology for laying them is different.

For installation power lines In the ground, protective cases are used that have high strength, elasticity and the ability to self-heal to their original dimensions - corrugated HDPE pipes.

Contents of the article

Types and characteristics

Thanks to , power communication (engineering) lines can be reliably and inexpensively laid underground in any corner of the city, as well as in a private house or holiday village.

In addition, laying the wire through a protective elastic pipe underground will protect it much better from mechanical, chemical or atmospheric influences, compared to ground laying. But first of all you need to choose the right one protective case, corrugation.

HDPE pipes that are suitable for protecting cables when installed in the ground:

flexible corrugated pipe;
double-sided corrugation (the outer side is made of low-density polyethylene, the inner (smooth) side is made of high-density polyethylene);
products made from recycled materials (technical insulating corrugation);
flexible corrugation, with reinforced coating;
hard and smooth pipe.

Properties of HDPE cases for installation in the ground

The corrugation used for pulling power wires along the ground should not have magnetizing properties. Therefore, for its manufacture, special ceramics, plastic or asbestos cement are most often used.

The diameter of the required protection directly depends on the length of the cable you want to install: a power cable of up to 5 meters can be placed in a 50 mm pipe; if its length is 5 meters and above, a product with a diameter of 100 mm is used.

There are several layers in a HDPE pipe:

outer layer – protective case, made of structural steel;
insulating layer over the screen (PVC);
the screen itself (Cu layer);
XLPE – insulating layer along the core;
core (material: Al or Cu).

The current will flow through the core, behind the screen and pipe (eddy currents). Regarding production of this product, high quality manufacturing takes place in special workshops, where visual designs (layouts) are used, taking into account the mechanism for further laying the power wire.

Advantages of corrugated HDPE pipe

Differs from metal products because it is much cheaper. Both products manufactured in accordance with GOST and pipes made from recycled materials can withstand long-term operation (the characteristics and color will differ slightly).

The main advantages of this product include:

the cable can be laid along a curved path without the use of auxiliary frames (but, despite the increased flexibility, if the corrugation is strongly bent, it will break, and you simply will not be able to stretch the power cable);
under normal conditions, the operating period reaches 50 years;
there is no need to use welding machines to connect individual sections;
a corrugated pipe is much lighter than a metal pipe;
has excellent electrical insulating properties and does not require grounding;
have excellent properties, therefore they are not destroyed under the influence of external negative factors;
resistance to temperature changes from -25 to +75 degrees;
do not accumulate condensate on the ground surface, do not oxidize and do not emit toxic substances.

Methods of laying in the ground

There are two ways to lay cables in the ground using corrugated cases: with digging a trench and trenchless laying. Which one is best depends on the installation location.

The method of laying cables through a protective corrugated pipe by digging a trench in the ground is ideal for private homes and summer cottages. The installation depth must be at least 70-80 cm. This type of installation does not require additional connecting couplings or blocks, but only for bringing the wire out of the ground and connecting to electrical system Houses.

Trenchless cable laying in HDPE pipes is carried out in hard-to-reach places and is most often used public utilities, since its implementation requires special equipment and devices.

Trenchless laying involves horizontal, directional drilling of soil without damaging its surface. A pipe with a wire inside is installed into the resulting well.

Preparatory stage

First of all, you need to decide in the best possible way installation of a corrugated case. For this purpose, all information about the work site and soil is collected (to avoid increased influence groundwater; alkalis, acids, etc.).

Underground installation is used in the case of a normal groundwater level, good soil conditions, and the absence of obstructing buildings or roadways. Also local conditions affect laying depth cable.

Before starting installation, it is also necessary to check the condition of the exits and connections of the corrugated cases - they must be clean, with a prepared (specially treated) surface.

For easy pulling, an oily substance is applied to the wire, which, moreover, acts as an alarm for the pressure level in the pipe. The wire must not be damaged or defective. The installation must be carried out as safely as possible, therefore, before starting work, all workers are additionally instructed, their tools and special clothing are checked.

Laying cables in the ground (video)

The process of laying cables in a pipe

At the power line design stage, it is necessary to determine the exact length of the channel into which the pipe will be inserted. Draw a plan for laying the power rein.

Let's look at the installation process by digging a trench:

on prepared soil with sand cushion(10 cm of loosened sand) a pipe is laid (without tension, in small horizontal waves);
we stretch the wire (the pipes can be laid with the wire already stretched inside or, by tying it to copper wire, stretch it after laying the corrugation);
cover the pipes with a layer of sand so that they are not visible;
cover them with a 15 cm layer of soil and compact it;
We stretch the signal tape along its entire length;
completely fill the trench and compact the soil;
We make a test measurement of the insulation resistance of the power wire.

You can stretch the cable in the pipe and install it by digging a trench yourself, without complex devices or equipment. All installation steps must be carried out according to the instructions, All materials have been tested and prepared for use.

Before you purchase it in the ground, be sure to make sure that it is not damaged by inspecting it along its entire length. Choice of quality building material and strict adherence to the instructions for installing utility power wires is the key to their long-term operation without the threat of short circuits or other life-threatening incidents.

To protect communication lines when laying wires, it is most often used for cables in the ground. Its use as a protective shell eliminates the risk of damage to products during the construction of highways and during their operation.

Low pressure can protect wires (incl. power cable) from the influence of soil, mechanical shocks, as well as stray currents. Read on to find out which ones are used to protect utility networks and how to choose the right ones.

Reasons for the high popularity of products

The most popular method of arranging electrical, communication, signaling and other networks is laying cables underground. And most often it is in the HDPE pipe. Therefore, manufacturers strive to make the range of manufactured polyethylene products as diverse as possible. special purpose. Despite the fact that this method of laying cables and wires is quite expensive, it is considered very popular.

For laying cables in the ground, they prevent the most different problems that are possible during the operation of utility networks.

The reasons for the growing popularity of these collectors in the construction of underground highways are:

Reduce the risk of line damage external factors(for example, in adverse weather conditions).
Protection from vandals and frost.
Fire due to short circuit is excluded.

What types of products can be used to protect wires?

On the building materials market you can find all kinds of products that are suitable for laying utility lines in the ground. These can be not only HDPE collectors, but also PVC pipes, asbestos or asbestos-cement, steel. However, most often polyethylene materials are used to protect wires and power lines underground.

HDPE pipes (pipe for cable in the ground) come in several types:

or heavy
Hard with a smooth shell
(with 2 walls)
Halogen-free.

The main types of pipes that can be used in the ground.

Collectors representing one type or another are designed for specific purposes. For example, products with double walls can be used for underground wiring, one of which is corrugated, and the second is a LDPE sheath. Corrugated pipe Not suitable for laying cables in the ground. Even though it is characterized by increased elasticity and strength.

You can understand what certain materials are used for by looking at the markings on the product. It indicates (GOST, shell diameter and thickness, strength, nominal pressure indicator, product class and sometimes its purpose).

If you need an HDPE pipe for underground cables, consider its purpose further application And specifications. Thus, corrugated material is suitable for hidden electrical wires in rooms. Usually these are highways that are created during the arrangement of houses and run into the walls or ceiling. The most durable DSK corrugated collectors can even be used in construction utility network in the floor (for pouring with concrete or cement).

Depending on the number of cables in the intended network, the pipe may be different diameters. For example, if 2-3 wires with a cross-section of 95 mm² are laid, a product with an internal diameter of 63 mm can be used. They are sold in 15 m coils or in separate sections.

If it is necessary to lay a line of 2-5 cables with a cross-section of 25 mm² each, you can use collectors with an internal hole of 32, 40 or 50 mm, etc. Some manufacturers offer HDPE manifolds with large diameters ranging from 160 mm to 250 mm. Such materials are sold in 12 m lengths or 100 m (200 m) coils.

Laying methods and features

Laying cables in pipes can be carried out above ground or underground. It is also practiced to lay sheathed cables indoors. If you need to arrange electrical or communication system in a residential building, before carrying out work you should familiarize yourself with the features of the process. First of all, it is recommended to lay networks at temperatures down to -30⁰С.

It is necessary to ensure the tightness of all joints and nodes on the line to eliminate the risk of moisture and other contaminants getting inside the collector. If the operating conditions of the network suggest the formation of condensation in the pipe, additionally install a draw-through pipe to collect excess liquid.

Having made sure that such points have been taken into account, you can proceed to the next stage of work. Laying a cable in the ground in a HDPE pipe is not a very labor-intensive process, the main part of which is digging trenches. After preparing a recess of the required size, the collector is first laid, and then the cable is inserted into it. After inspecting the lines for damage and depressurization of nodes, developers fill the structure with sand and earth. Finally, warning tape can be laid around the entire perimeter.

Valuable product qualities

HDPE pipes designed for cables and their protection in the ground (their price is relatively low, if we take into account their long service life) have a huge number of valuable qualities:

lightweight and easy to guide the cable using a probe;
possibility of underground wiring with large radius angles;
resistance to different conditions operation (from mechanical influences before temperature changes);
possibility of operation for 50 years or more;
light weight;
use without additional grounding, etc.

As you can see, the use of HDPE pipes when laying underground utility lines is the key to their successful and reliable operation. Therefore, it is important to choose the right collector and take into account all the nuances of its use.

The video demonstrates testing corrugated materials for PVC and HDPE electrical wiring for fire:

The concept of “dacha” often implies the presence of not only the main residential building, but also several additional economic facilities.

Garage, summer cuisine, gazebo, sauna - these buildings are necessary on the farm and must be uninterruptedly supplied with electricity.

Subtleties of underground wiring in a summer cottage. How to choose a cable corrugation

One of the ways to lay an electrical cable through a summer cottage is underground. This option is solid, reliable, aesthetic (wires do not spoil appearance courtyard). However, it requires strict adherence to technology and instructions. A mandatory item is the purchase of cable corrugations and a special protective sheath.

Of course, you need to pay special attention to choosing a cable suitable for laying in the ground - this cannot be done without consulting an electrician. But it is equally important to choose the protection in which it (the cable) will be “packed” when laid at depth in order to ensure its integrity and functionality for the entire period of operation.

The main thing you need to know: underground wiring requires the use of special HDPE corrugation. “HDPE” is an abbreviated name for the main material of such a pipe, low-density polyethylene. This corrugated pipe is characterized by increased strength and has a number of specific characteristics. The installation process itself is another story, but below we will share what we obtained from an electrician advice on selection.

The main differences between corrugations for underground cable laying and conventional ones

Double-walled design: the outer shell is corrugated, which guarantees high strength of the pipes, and the inner wall is smooth (this ensures easy cable pulling along the entire length).

Resistance to shock loads and vibration and at the same time plasticity in operation. This allows you to use HDPE corrugation for laying cables on open areas, and in soil or concrete screed.

A wide range of operating temperatures that the corrugation can withstand without damaging consequences (from -40 to +90°C).

The double-walled corrugated pipe in coils is equipped with a special broach (probe) for the convenience of threading the cable along long sections. Bays are found in lengths of 20, 50 and 100 meters (larger lengths for wiring on private properties are rarely required).

Visually, a corrugated pipe suitable for underground use also differs from a regular gray PVC pipe in red or orange(less common, depending on the manufacturer, is black).

The diameter of the HDPE corrugation depends on the characteristics of the cable selected for laying in the ground. For dacha underground wiring, most often a pipe with an external Ø40 mm and an internal Ø32 mm (also the minimum possible) is chosen. For example, .

Why? The fact is that for underground installation in the courtyards of private cottages, electricians often recommend VVG 3x2.5 with an external Ø10.5 mm (the cross-section of such a cable is sufficient for the household power supply of most outbuildings). Judge for yourself: a cable of this girth fits into double layer pipe with internal Ø32 mm. The maximum possible values of corrugated pipes reach Ø200 mm, but these are used for purely industrial purposes.

When purchasing corrugated pipes in pieces 6 meters long (by the way, not all specialized stores sell such pieces, check this point right away) be prepared for the fact that there is no broach in them. And this is justified because It is not difficult to stretch the cable over a short length without pulling.

Try to choose even a corrugated pipe for laying in the ground, non-flammable.

The compressive strength of the selected pipe should be high - focus on a minimum of 6-8 kPa.

But the level of resistance to ultraviolet radiation can be neglected here, because underground the issue of sun protection is not relevant.

Special corrugation is important

Imagine the titanic physical, time and material costs that will entail replacing a failed cable buried in the ground summer cottage at a depth of 70-80 cm. This is not for you to dig up potatoes! Purchasing a special protective corrugation is not an extra (note, one-time) expense, but the necessary insurance in order to enjoy the benefits of your dacha comfortably and easily for many decades.

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