Direct quote for installation of signal tape. Signal and protective signal tapes

Question: Good afternoon, Liliya Yakovlevna! Please tell me what price should be applied for covering a cable with signal tape? Is it correct to use the price FERm08-02-143-01 “Coating a cable laid in a trench with bricks: one cable”, excluding the cost of mechanisms? Is it necessary to apply a reduction factor to the basic salary? Or should I use a different rate? Thank you.

Answer: Incl. and to Question No. 63.
Hello! The question of determining the costs of laying signal tape has been around for a long time. The need to create estimate standards for this type of work has already become “overripe.” Of course, there is a ready-made recipe, but it does not at all meet the aspirations of the estimators. The only correct answer is contained in clauses 2.3 (third paragraph from the bottom) and 2.15 of MDS 81-35.2004, as well as clauses 1.4 ÷ 1.5 of MDS 81-37.2004, where in such situations it is proposed to develop appropriate individual estimate standards for the work technologies provided for in the project. Having analyzed the available solutions of estimators (methods for determining the estimated cost) of this issue and those posted on the forums of various sites, I was once again convinced of the ingenuity of the estimate compilers. The used (proposed) standards of the following Collections: No. 12 GESN-2001 (FER, TER) “Roofs” (roof fencing or as a vapor barrier device for a gasket in one layer), GESNm-2001 (FERm, TERm) No. 8 “Electrical installations” (coating cable laid in a trench with bricks with the replacement of basic materials), No. 10 “Communication equipment” (laying identification tape), do not reflect the consumption of resources, and therefore the costs of carrying out work on the use of signal tape in cases of laying electrical cables for different voltages. Many, I believe, mistakenly believe that the signal tape is laid simultaneously with the cable and the worker running, unwinding a roller with tape along the laid cable, will complete the job. Not so! Please study the technology of performing work not only on laying the tape, but also pay special attention to the accompanying work, namely the thoroughness and accuracy of backfilling the trench with soil, with the cable and signal tape laid in it. The use of warning tapes is regulated by PUE and SNiP 3.05.06-85 “Electrical devices”. In clause 2.3.83 “Laying cable lines in the ground”, chapter 2.3. “Cable lines with voltage up to 220 kV” PUE provides the rules and requirements for carrying out this work and here are some of them:
“It is not allowed to use signal tapes at the intersections of cable lines with utility lines and above cable couplings at a distance of 2 m in each direction from the crossed utility line or coupling, as well as at the approaches of lines to switchgears and substations within a radius of 5 m.
The signal tape should be laid in a trench above the cables at a distance of 250 mm from their outer covers. When placing one cable in a trench, the tape must be laid along the axis of the cable; with a larger number of cables, the edges of the tape must protrude beyond the outer cables by at least 50 mm. When laying more than one tape across the width of a trench, adjacent tapes must be laid with an overlap of at least 50 mm wide.
When using warning tape, laying cables in a trench with a cable cushion, sprinkling the cables with the first layer of earth and laying the tape, including sprinkling the tape with a layer of earth along the entire length, must be carried out in the presence of a representative of the electrical installation organization and the owner of the electrical networks.” In this case, work should be carried out in compliance with such points of this chapter of the PUE as clauses 2.3.84÷2.3.87, etc.
In addition, you should remember and know that signal tapes are used as underground warning signals about cable networks and pipelines laid in the ground and they are not protective, protecting against mechanical damage to the insulation, sheathing of cables or pipes. I draw the following conclusion: it is necessary to draw up estimate standards taking into account the technology and features of the work on laying signal tapes of all sizes and the number of cables in the trench. Signal detection tapes “Electro” LSE 150 ÷ ​​LSE 900 (respectively tape width: 150, 250, 300, 450, 600, 750 and 900 mm) are used to identify electrical cables with the logo “CAUTION CABLE”, produced wound on rollers of 100 p. .m, thickness - 300 microns and color red (GOST 2245-002-21696750-04). For comparison, I will give the characteristics of other tapes used, for example:
“Signal detection tapes LSO 40, 70 “Optics” are intended for identification of optical cables. The color is yellow, the text on the tape is “Caution, optical cable.” Width 40 and 70 mm, tape thickness 100 microns, roller winding 500 meters.”
“Signal detection tapes LSS 40, 50, 75, 100 LSS “Svyaz” are intended for identification of communication cables. The color is orange, the text on the tape is “Do not dig, below the cable.” Available in widths of 40, 50, 75 and 100 mm, thickness 300 microns. Roller winding 250 meters.”
It turned out a lot and took a long time, but I wanted it to be clear to everyone, namely: compilers of estimate standards, designers, installers, customers, inspectors, etc. I wish you success! Sincerely, L.Ya. Podyniglazova

Cable lines for transmitting electricity from a source to a consumer can be laid in trays or channels, along special overpasses or galleries, in pipes, tunnels, or fixed on the walls of buildings. However, the most common method remains laying the cable in the ground. Its popularity is explained primarily by its cost-effectiveness, as well as the good protection of the conductor from the effects of weather conditions and electromagnetic fields. Laying a cable in the ground occurs in several stages, performed in a strictly defined sequence.

• selection, marking and layout of the cable route
• mechanized or manual trenching
• sand bed filling device
• cable laying (if necessary, pulling in pipes)
• cable powder
• cable protection with a brick (if provided by the project)
• signal tape laying
• backfilling the cable line trench with soil

Correct laying of the power cable in the ground and the stages of laying it in trenches affect the price of work per linear meter.

Selection, marking and breakdown of the route for laying the cable in the ground

The route must meet several requirements. First of all, it is necessary to take into account the safety of operation, as well as provide for the possibility of its subsequent maintenance. At the same time, in order to reduce the costs of work and materials, the route should, if possible, be laid over the shortest distance.

The distance from the cable to other communications, forests, building foundations, roads, supports and other obstacles should not be less than the minimum established by the standard. If this requirement cannot be met, additional measures are taken to protect the cable.

Mechanized or manual digging of a trench for cable laying

Regardless of the method of excavation work, it can only be carried out after obtaining the necessary permits issued by the relevant administrative authorities. When crossing with other communications or passing the route in close proximity to them, coordination with the operating organizations is also required.

Before digging a trench, the route is carefully inspected for the presence of substances in the soil that could destroy the protective sheath of the cable. If there are any, and there are no ways to bypass these sections, measures are taken to additionally protect the cable. The standard trench depth for laying cables in a populated area is 1-1.2 meters, but it can be changed depending on the type of soil and other conditions.

Device for adding a sand cushion under the power cable

The sand cushion reduces the mechanical load on the cable during subsequent compaction of the soil. The thickness of the sand layer is at least 100 mm. It is allowed to use ordinary quarry sand, as well as loosened soil without foreign inclusions.

Cable laying and pulling in pipes

The cable in the trench is laid with a small margin, in wavy twists. This is necessary to prevent its tension and rupture during soil subsidence and temperature fluctuations. Where it intersects with other communications, when passing at shallow depths, when protection from aggressive environments is necessary, or in other cases when there is a high risk of damage, the cable is placed in plastic, asbestos-cement, ceramic or steel pipes.

Cable powder

Cable powdering is carried out in stages. First, it is covered with a 100 mm thick layer of sand. Backfilling with soft soil, which should not contain foreign solid inclusions, is also allowed. Before backfilling, the cable insulation resistance and the absence of a short circuit to the ground and between the cores are checked.

Cable protection with a brick

In cases where there is a high risk of mechanical damage to the cable, for example, as a result of maintenance work on communications located in close proximity to the route, additional cable protection with bricks can be used.

Laying warning tape to avoid damage to cable lines

Laying a warning tape reduces the risk of cable damage when excavating mechanically. It is laid at a distance of 250 mm from the cable surface without breaks. The tape is made of polymer or other materials that are resistant to aggressive environments, and the warning inscription “Caution cable!” is applied to its upper side.

Backfilling the cable line trench with soil

The final backfilling of the cable line trench with soil is carried out sequentially, with compaction every 200 millimeters. The soil used for backfilling should not contain solid inclusions - stones, construction waste

Installation of connecting cable boxes

Installation of couplings is necessary in cases where the total length of the route exceeds the length of the cable in the coil. Before installing the couplings on the cable length determined by the technical documentation, the protective covers are sequentially removed. In this case, a special heat-shrinkable tube is put on the cleaned conductors, which ensures insulation from each other after installation of the coupling. If there is a screen in the cable, it must be restored by soldering.

Posted 10/27/2009 (valid until 10/27/2010)

Studying TNLA is the path to the emergence of new resource-saving technologies.

It seems that everyone reading this article has at least once dug up the soil on their summer cottage. Several years ago, the author of this article purchased a plot of land in one of the villages near Minsk. Putting the land in order for planting turned out to be a very problematic task, since the previous owners buried garbage and waste in the ground. The shovel did not pierce the plastic film buried in the ground, “springing” back from it, so the exhausted summer resident had to first remove the top layer of soil, remove the obstacle in the form of a film, and only then continue digging up the summer cottage.

The properties of polyethylene have been known for a long time. In 1933, raw materials in the form of granules and the first products made from them were produced in England. The result is a plastic material with good dielectric properties, impact-resistant, unbreakable, with low absorption capacity, physiologically neutral, and odorless. Has low vapor and gas permeability. Polyethylene does not react with alkalis of any concentration, with solutions of any salts, carboxylic, concentrated hydrochloric and hydrofluoric acids. Resistant to alcohol, gasoline, water, oils. Destroyed by 50% nitric acid, as well as liquid and gaseous chlorine and fluorine. Virtually harmless. Polyethylene is easily recycled by all major plastics processing methods.

A study of foreign construction practice has shown that polymer materials are widely used in the construction of underground utility networks and communications as gas and water pipes, insulated cables, etc. There is also a “niche” in electrical grid construction.

In the Republic of Belarus, solid clay bricks are traditionally used to protect cable lines from mechanical damage (despite the rather irrational nature of this application). Close communication with our power engineers, builders, as well as a study of the technical regulatory framework of the former USSR showed that the market has been waiting for a new product for a long time, and the issue of replacing brick with another material has received attention over the past 20 years.

At the end of the 1980s. Soyuzenergo issued a letter No. 106-25/57 dated December 30, 1986 “On the use of tapes made of polymer compounds to protect cables” and “Decision of the Main Technical Directorate and Main State Energy Supervision of the USSR Ministry of Energy dated June 10, 1990 No. E-4/90 on changes requirements of Ch. 2.3 PUE “Cable lines with voltage up to 220 kV”, signed by the Deputy Head of the Main Technical Directorate and the Deputy Head of the Main State Energy Supervision Department of the Ministry of Energy with the following content: “... to gain experience in operating cable lines laid in trenches using signal plastic tapes instead of bricks, using the specified tapes when laying cable lines up to 20 kV. Experience in operating these cable lines has not revealed any negative consequences of replacing brick with warning plastic tape. Taking this into account, as well as the shortage of bricks, the Main Technical Directorate and the Main State Energy Supervision Office consider it possible to allow wider use of signaling plastic tapes when laying cable lines in the ground. To streamline the use of signal plastic tapes, organizations of the USSR Ministry of Energy and the USSR Ministry of Montazhspetsstroy have developed technical requirements for the tape (application), which should be used to guide the selection of tape material and its technical characteristics. In order to expand the scope of application of signal plastic tapes when laying cable lines in trenches, the Glavtechnical Directorate and Glavgosenergonadzor, taking into account the requirements of CHiP 3.05.06-85 “Electrical devices”, regulating the use of signal tape, decide to make changes to Chapter. 2.3 “Cable lines with voltage up to 220 kV” PUE, sixth edition, adding clause 2.3.83 at the end with the following text:

“For cable lines up to 20 kV, except for lines above 1 kV that supply power receivers of category 1*, it is allowed in trenches with no more than two cable lines to use signal plastic tapes instead of bricks that meet the technical requirements approved by the USSR Ministry of Energy. The use of signal tapes is not allowed at the intersections of cable lines with utility lines and above cable couplings at a distance of 2 m in each direction from the crossed utility line or coupling, as well as at the approaches of lines to switchgears and substations within a radius of 5 m. Signal tape must be laid in a trench above the cables at a distance of 250 mm from their outer covers. When placing one cable in a trench, the tape must be laid along the axis of the cable; with a larger number of cables, the edges of the tape must protrude beyond the outermost cables by at least 50 mm. When laying more than one tape across the width of a trench, adjacent tapes must be laid with an overlap of at least 50 mm wide.

When using warning tape, laying cables in a trench with a cable cushion, sprinkling the cables with the first layer of earth and laying the tape, including sprinkling the tape with a layer of earth along the entire length, must be carried out in the presence of a representative of the electrical installation organization and the owner of the electrical networks.”

To be fair, I would like to note that on the eve of the complete collapse of the USSR, the Scientific and Production Association “Belstroynauka” of the State Construction Committee of the BSSR developed recommendations for the pilot industrial implementation of protective polymer coatings when laying electrical cables with a voltage of 0.4–10 kV, where, in particular, the physical and mechanical properties, The polymer materials used to protect underground cables were required to have a tensile strength of over 10 MPa. Unfortunately, the accumulated potential of the construction science of the BSSR was not practically in demand in the electrical grid construction of the already independent Republic of Belarus, where in the second decade of the 21st century brick continues to be used everywhere to protect underground cable lines, which is regulated by clause 2.3.83, in our opinion, morally and technically outdated, 6th edition of the PUE, the last changes to which were made before August 31, 1985. At the same time, the use of the protective properties of polyethylene tapes studied by Belarusian scientists was limited to the development of “Temporary instructions for the use of signal tapes”, approved by some regional power grids of the Republic Belarus.

Rice. 1. Appearance of the tape.

Communication with Lithuanian power engineers on this issue showed that the Lithuanian SSR, despite its active desire to secede from the USSR, most fully complied with the instructions of Soyuzenergo letter No. 106-25/57 dated December 30, 1986 “On the use of tapes made of polymer compounds to protect cables." It was from this time that Lithuania began to develop its own technical regulatory documents regulating and rationalizing the use of building materials for the protection of underground cable lines. Technical terms were introduced: “Polyethylene signal tape for cable lines” and “Polyethylene protective tape for cable lines”, standards for their production were developed, and their areas of application were determined. The Soviet “Rules for the Construction of Electrical Installations” were revised into the “Rules for the Installation of Electrical Equipment”, which have already gone through several reissues in this short period of time due to the increasing scientific and technical integration of Lithuania with the European Union. In this regard, I would like to provide a translation of the chapter in the current edition of the Lithuanian “Rules for the installation of electrical equipment” dedicated to underground cable lines:

"VII. Cable lines in the ground

169. Protection of cables laid in trenches from mechanical damage depends on the significance of the cable, its voltage, depth and location of installation. The mechanical strength of cable protective equipment (protective tapes) must be at least 6 MPa.

Cables with voltages of 110 kV and above must be covered with reinforced concrete slabs with a thickness of at least 50 mm.

Cables with a voltage of 6–35 kV in the city must be protected from mechanical damage by covering them with special caps, slabs, solid clay bricks or protective tapes 1.5–5 mm thick at a distance of 0.10–0.15 m above the cable or cables must be laid in ceramic, plastic, asbestos-cement or cast iron pipes. The width of the protective tape for one cable must be at least 100 mm, for two cables – 200 mm. When using protective tapes, at a distance of 0.3 m from the ground surface, for each parallel laid cable, a warning tape with a thickness of at least 0.5 mm is laid with the inscription “Attention! Cable!".

Cables with a voltage of 6–10 kV laid in uncultivated soil at a depth of at least 0.7 m, and with a voltage of 35 kV at a depth of at least 1 m, must be protected from mechanical damage by covering them with protective tapes and laying warning tapes at a depth of 0.3 m from the surface of the earth.

If cables are laid in pipes or covered with special caps, slabs, or solid clay bricks, then it is not necessary to lay signal tapes.

It is not necessary to protect cables with a voltage of 6–35 kV in arable lands from mechanical damage, however, it is necessary to lay a warning tape at a depth of at least 0.5 m from the ground surface.

Cables with voltages up to 1000 V, laid at a depth of 0.35–0.7 m and in those sections of routes where there is a risk of damage (for example, in places of frequent excavation), must be protected with slabs, caps, solid clay bricks or laid in pipes . In other cases, in the city, as well as under the pavement and in uncultivated soil at a depth of 0.3 m from the surface of the earth, in arable soil at a depth of 0.5 m from the surface of the earth, it is enough to lay only a warning tape ... "

In January 2009, having summarized all available information and assessed the relevance of new resource-saving technology for our country in the context of the global economic crisis, Interbeltrade LLC decided to begin developing technical documentation for the production of products that had never previously been produced in the Republic of Belarus. The main problem that had to be solved was the requirements for the product and the properties that this product should have, since there are no technical regulations for this kind of product. I will not describe all the attempts to obtain intelligible information from practitioners in this area, I will only quote verbatim the recommendation received from power engineers: “We believe that you have to go to Gosstandart, everyone knows there...” Indeed, the advice turned out to be practical. An appeal to BelGISS (the head enterprise of Gosstandart in the field of technical regulation and standardization) and the subsequent scientific and methodological assistance not only solved the problem at hand, but also showed the importance and significance of the knowledge and application of technical regulations. The range of existing polymer materials is diverse: GOST 26996-86 “Polypropylene and propylene copolymers”, GOST 16338-85 “Low pressure polyethylene”, GOST 20282-86 “General purpose polystyrene”, GOST 19459-87 “Moulding polyamide copolymers”, GOST 16337- 77 “High pressure polyethylene”. These standards established the range of raw materials for security and signal tape.

Analysis of the requirements contained in the TNLA data determined the requirements for the tape we are developing: tensile strength, frost resistance, specific surface electrical resistance, electrical strength. A comparative analysis of the physical and mechanical properties of the above polymers, as well as the final products obtained from these polymers (GOST 12998-85 “Polystyrene film”, GOST 10354-82 “Polyethylene film”), allowed us to draw an unambiguous conclusion in favor of the use of high-quality polyethylene pressure for the production of protective signal tape for the protection of underground cable lines.

In June 2009, TU BY101333870.002-2009 “Protective and signal tape of the LZS series” LLC “Interbeltrade”, Minsk, was registered with Gosstandart. In September 2009, GPO Belenergo approved these technical specifications without comments, thereby allowing the use of protective signal tape in the electrical grid construction of the Republic of Belarus. The protective signal tape is made of high-density polyethylene (or its waste) and is used to protect cable lines with voltages up to 20 kV from mechanical damage and to mark places for laying cables laid in trenches underground. The protective signal tape has a red front side with a warning inscription (Fig. 1) and must be laid in a trench above the cables at a distance of 250 mm from their outer covers on compacted fine soil poured onto the cable, without debris (Fig. 2). When laid in this way, a 3.5 mm thick polyethylene sheet has increased resistance to mechanical stress.

Rice. 2. Laying the tape in the trench above the cable.

Despite the fact that, according to European requirements, the minimum value of the withstand mechanical load for the material used in the protection of underground cable lines should be at least 6 MPa, and from the recommendation on the pilot-industrial introduction of protective polymer coatings when laying electrical cables, NPTO "Belstroynauky" Gosstroy of the BSSR follows the requirement for tensile strength of such coatings is more than 10 MPa, the specialists of our company decided to set much higher strength requirements for their tape. From the protocol issued during tests on the protective signal tape by the Testing Center of OAO Stroykompleks, it follows that the minimum value in MPa for longitudinal tension of this product is 14.86, and in transverse tension - 13.99. At the same time, according to STB 1160-99 "Brick and ceramic stones", the average tensile strength of solid clay brick grade 150, used to protect underground cable lines, is 2.8 MPa in bending. In addition, the test report of the Testing Center confirmed the high resistance of the protective signal tape to shock loads.

Estimated calculations for a conditional cable line confirmed the reduction in the cost of its construction when using this tape. To deliver the protective-signal tape to the construction site, a crane and heavy trucks are not needed, as required by the delivery of bricks, and the use of machines and mechanisms is not required when laying this tape directly into the trench to protect the cable, and the laying itself takes little time. The weight of a roll of 50 meters of 250x3.5 mm tape is 35 kg. With a brick width of 12 cm, 417 pieces are needed to cover 50 meters of cable. brick, its weight will be about 1330 kg. We also consider (an important circumstance in favor of the use of tape to protect against mechanical damage to the cable) that the use of solid clay bricks is advisable only for its intended purpose - exclusively for the construction of buildings.

In conclusion, I would like to say that the study and application of domestic standards makes it possible to create new products and technologies that are not inferior to foreign analogues.

Discuss on the forum

When drawing up a project for laying a cable line, you should take into account the need to lay signal tape. What price should be taken into account in this case? Is it possible to use the FERm pricing, which specifies the conditions for covering a cable laid in a trench with bricks? What coefficients should be taken into account in this case? We answer these questions with the head of the department of estimate standards of the company “TsNIIEUS” Lidia Podyniglazova.

According to the expert, the need to determine installation costs has been around for a long time. However, there are still no standards in this area. And it is not entirely correct to solve the issue by simply eliminating the cost of operating the mechanisms. Individual estimate standards should be developed that take into account the types of work provided for in a specific project.

Most design organizations use standards that are completely inappropriate for this type of work. Non-specialized publications do not reflect either technology or resource consumption. Therefore, in the end, the costs of purchasing and installing a signal line turn out to be completely different from what was envisaged in the project. And this already means a discrepancy with the estimate and significant financial problems.

Accounting for installation technology

The inattention shown by designers to the preparation of cost estimates for laying the signal tape is based on an erroneous idea of ​​​​the features of the work technology. Most of the technique seems to be extremely simple: here the cable is laid, here a man with a reel in his hands runs over the trench and unwinds the signal tape. Then you just need to dig a trench, what other additional costs can there be?

But installation according to current standards looks completely different! The technology includes the main and related works regulated by the PUE for laying cable lines in the ground. In particular, they note that signal tapes cannot pass at the intersections of cable ducts with other engineering communications. That they should not be laid over cable boxes, but only at a distance of two meters from them in each direction. They cannot be located in the immediate vicinity of substations, transformer devices, but only at a distance of at least five meters. There are other norms that are important to consider when drawing up a project estimate. We will talk about them in a new review.

03.11.16

Question No. 129; Date: 05/18/2010

Question: Good afternoon, Liliya Yakovlevna! Please tell me what price should be applied for covering a cable with signal tape? Is it correct to use the price FERm08-02-143-01 “Coating a cable laid in a trench with bricks: one cable”, excluding the cost of mechanisms? Is it necessary to apply a reduction factor to the basic salary? Or should I use a different rate? Thank you.

Answer: Incl. and to Question No. 63. Hello! The question of determining the costs of laying signal tape has been around for a long time. The need to create estimate standards for this type of work has already become “overripe.” Of course, there is a ready-made recipe, but it does not at all meet the aspirations of the estimators. The only correct answer is contained in clauses 2.3 (third paragraph from the bottom) and 2.15 of MDS 81-35.2004, as well as clauses 1.4 ÷ 1.5 of MDS 81-37.2004, where in such situations it is proposed to develop appropriate individual estimate standards for the work technologies provided for in the project. Having analyzed the available solutions of estimators (methods for determining the estimated cost) of this issue and those posted on the forums of various sites, I was once again convinced of the ingenuity of the estimate compilers. The used (proposed) standards of the following Collections: No. 12 GESN-2001 (FER, TER) “Roofs” (roof fencing or as a vapor barrier device for a gasket in one layer), GESNm-2001 (FERm, TERm) No. 8 “Electrical installations” (coating cable laid in a trench with bricks with the replacement of basic materials), No. 10 “Communication equipment” (laying identification tape), do not reflect the consumption of resources, and therefore the costs of carrying out work on the use of signal tape in cases of laying electrical cables for different voltages. Many, I believe, mistakenly believe that the signal tape is laid simultaneously with the cable and the worker running, unwinding a roller with tape along the laid cable, will complete the job. Not so! Please study the technology of performing work not only on laying the tape, but also pay special attention to the accompanying work, namely the thoroughness and accuracy of backfilling the trench with soil, with the cable and signal tape laid in it. The use of warning tapes is regulated by PUE and SNiP 3.05.06-85 “Electrical devices”. In clause 2.3.83 “Laying cable lines in the ground”, chapter 2.3. “Cable lines with voltage up to 220 kV” PUE provides the rules and requirements for carrying out this work and here are some of them: “The use of signal tapes is not allowed at the intersections of cable lines with utilities and above cable couplings at a distance of 2 m in each direction from the intersection communications or couplings, as well as at the approaches of lines to switchgears and substations within a radius of 5 m. The signal tape should be laid in a trench above the cables at a distance of 250 mm from their outer covers. When placing one cable in a trench, the tape must be laid along the axis of the cable; with a larger number of cables, the edges of the tape must protrude beyond the outer cables by at least 50 mm. When laying more than one tape across the width of a trench, adjacent tapes must be laid with an overlap of at least 50 mm wide. When using warning tape, laying cables in a trench with a cable cushion, sprinkling the cables with the first layer of earth and laying the tape, including sprinkling the tape with a layer of earth along the entire length, must be carried out in the presence of a representative of the electrical installation organization and the owner of the electrical networks.” In this case, work should be carried out in compliance with such paragraphs of this chapter of the PUE as clauses 2.3.84÷2.3.87, etc. In addition, you should remember and know that warning tapes are used as underground warning signals about cable networks and pipelines laid in the ground and they are not protective, protecting against mechanical damage to insulation, cable sheaths or pipes. I draw the following conclusion: it is necessary to draw up estimate standards taking into account the technology and features of the work on laying signal tapes of all sizes and the number of cables in the trench. Signal detection tapes “Electro” LSE 150 ÷ ​​LSE 900 (respectively tape width: 150, 250, 300, 450, 600, 750 and 900 mm) are used to identify electrical cables with the logo “CAUTION CABLE”, produced wound on rollers of 100 p. .m, thickness - 300 microns and color red (GOST 2245-002-21696750-04). For comparison, I will give the characteristics of other tapes used, for example: “Signal detection tapes LSO 40, 70 “Optics” are intended for identifying optical cables. The color is yellow, the text on the tape is “Caution, optical cable.” Width 40 and 70 mm, tape thickness 100 microns, roller winding 500 meters.” “Signal detection tapes LSS 40, 50, 75, 100 LSS “Svyaz” are intended for identification of communication cables. The color is orange, the text on the tape is “Do not dig, below the cable.” Available in widths of 40, 50, 75 and 100 mm, thickness 300 microns. Roller winding 250 meters.” It turned out a lot and took a long time, but I wanted it to be clear to everyone, namely: compilers of estimate standards, designers, installers, customers, inspectors, etc. I wish you success! Sincerely, L.Ya. melons

Energy engineers believe: preparation of a project for carrying out work in accordance with the PUE. Although the sixth edition is greatly truncated by the seventh, today we will look through the old one and refresh our memory. PUEs evoke deep respect from the masters; the rules prescribe elementary truths. Most of the text (if not all) has been agreed upon with the relevant government authorities. Cable laying in a trench is carried out by an organization that can provide qualified personnel and holds a license.

Laying the cable correctly

We would strongly recommend studying PUE 6, finding out how to correctly lay the power cable in a trench. The document is devoid of legislative support (although approval was carried out, it has become overgrown with feather grass over time); many organizations are guided by verified lines to this day. Reading the document is complicated by its complex structure. Basic notes that a beginner needs to know so as not to get confused:

1. Protected and unprotected cables are understood as a unified definition by disclosing standards. A separate GOST for SIP has been issued. Paper products are called protected. This means that the installation of SIP is carried out according to the scheme specified by the PUE for protected cables.
2. The description of working with electrical lines begins with a section (discarded PUE 7 of the new edition), links are provided to other parts of the rules.
3. The analysis begins with general provisions, according to the increase in voltage. Not strictly. For example, specific provisions are indicated for all lines; the full rules, complete with disclaimers, are given below. The section on voltage up to 220 kV discusses laying other cables in the ground. Violation of the chronological order will confuse the beginner; you need to carefully read section 2, select the one that relates to the existing line (for most people, 220 or 380 volts, up to 1 kV). Russia introduced 230 volts after the text of PUE 6 was approved. A review of the VashTekhnik portal provides verbatim information.

Cable trench

Having read PUE 6, we will say the following regarding cable laying in a trench...

Laying depth

The cables are laid to a depth of 0.7 meters, a fact clearly demonstrated in YouTube videos. At the same time, a nuance is kept silent: the distance is specified for cables in the range up to 35 kV. Further the depth increases to a meter. But not just relative to the soil, but to the planning mark. To the best of our understanding - a certain sign left by surveyors on the plan, transferred to the area. The soil can be uneven, and you have to find some average level. The depth reaches 1.5 meters, starting with a voltage of 110 kV. Evaluate YouTube videos with a touch of criticism.

Under plowing, the 6 - 10 kV cable is laid deeper - buried 1 meter. There are some other exceptions to the rule.

Cable hole

The hole is dug with a slight slope of the walls outward. The width is not as important as fulfilling the bookmark requirements. No more than six cables with voltage up to 35 kV are laid together. There is another trench under the remaining swarm, and so on. The distance between groups exceeds 0.5 meters.

The trench is obviously dug 10 centimeters deeper. According to the rules, drainage sand is poured under the cable and compacted. There is no special technique - craftsmen use their own legs. The chosen method is determined by the scope of work.

The trench for laying the cable is equipped no closer than 0.6 meters to the foundation of the building or any other underground engineering structure. Curiously, not a word is said about the blind area (the path around the perimeter of the house). The normalized distance to tree trunks is at least two meters. Indirectly indicates: the area of ​​the route is devoid of green spaces (in fact, industrial lines are specially marked, everyone has seen signs: be careful, cable!). The forest is being uprooted. The specified distance is reduced when laying forest belts in the territory of parks (the project is approved).

Laying steel cable

What follows is determined by the type of cable. Those with steel armor are covered with cleaned earth (devoid of construction debris). 25 cm above the cable, lay a tape of insulating material on which it is written: there is a high-voltage line. The PUE is categorically at odds with some practices, which are limited to this.

According to the standards, it is necessary to protect the cables from above, using special ceramic (for lines above 35 kV - reinforced concrete) slabs, bricks (for lines above 35 kV is unacceptable) made of the same material with a thickness of at least 5 cm. Ordinary exceeds the specified dimensions. Bricks are laid across the line, tiles - as indicated by the manufacturer's instructions. The vertical distance to the cable is 15 cm. For support, two rows of bricks are laid on the sides along the line (one each from left to right), and a transverse one is placed on top.

Please note that the ground above the cable must be clean. The foremen, trying to find the soil, sprinkle it with sand. There is still a mole warning tape on top of the bricks; special slabs contain this on the surface. No additional signaling is required. Signal tape for laying cables in a trench is laid purely theoretically.

Laying armor cable

The armored cable, according to what is written, is laid in the ground; other grades need protection. You can use corrugated lines (for power lines black, red, communication lines - blue), HDPE pipes. The first is used in most cases; when passing roads, when horizontal drilling is carried out, polyethylene is more often used. Significantly reduces friction and simplifies the cable laying process.

Protective corrugation

Brick protection

When laying a depth of 1 - 1.2 meters, it is allowed to do without protection by slabs for networks below 20 kV (including 220/380 V). It is allowed to lay the brick lengthwise, if there is only one cable, the trench width does not exceed 25 cm. It will help to save approximately twice the cost of the material. The use of silicate, hollow bricks is prohibited. Cables with voltages below 1 kV may be deprived of protection.

One exception that can be used to save money. The route is formed by 5 cables up to 20 kV (not supplying category I consumers). According to the rules, you need to protect it with slabs and bricks. And here smart heads came up with the idea of ​​dividing it into three trenches (leaving the required half a meter), where the cable is laid according to the 2x2x1 pattern. Laying cables in a trench using the specified PUE method is an exception. You can limit yourself to laying warning tape. Bricks and slabs constitute a net saving. Is the volume of excavation work increasing? In the PPR for cable laying in a trench, we will provide for the use of equipment that leaves a wide trail (over one and a half meters). We will fill the bottom with sand, install the cables according to the diagram, add clean earth, and lay a warning strip.

Signal tapes

The technological map of the work excludes the use of signal tapes in the area where cables intersect with utilities (water supply, sewerage) 2 meters in each direction, above the couplings. Similar requirements, only with an increase in distance to 5 meters, exist for approaches to distribution boards and substations. The signal tape is laid with a margin of at least 5 cm on the sides of the cable axes, adjacent tapes (if there is a wide route) are overlapped by 5 cm.

High voltage warning tape

Trench cable laying technology

There are restrictions on the horizontal distance between lines: 10 cm - below 10 kV; 25 cm - 10-35 kV; 50 cm – between cables operated by organizations and above 110 kV. However, the vertical distance is hushed up (the authors did not find it). Some organizations skillfully use the space by assembling in pairs with bundles. In each cables are arranged vertically. Allows you to significantly reduce the width of the recess, avoiding the use of bricks protecting the routes. Digging a trench for laying cables is simplified and financial costs are reduced.

Parallel cable management

Parallel laying of communication cables in a trench, power lines, and utilities is allowed. The distance to the latter is at least one meter (to gas pipelines, heating pipelines - 2 meters). The distance between the cables is maintained according to the instructions given above. The distance to utilities can be reduced by half of lines up to 35 kV, using installation in a protected version (inside the HDPE pipe), the range is completely ridiculous - 25 cm. Some other exceptions to the PUE are given.

Cable crossing points

Where cables intersect, the vertical distance is at least 0.5 meters. Parallel following is hushed up! At an intersection, the size of the gap can be reduced by using concrete slabs and pipes with a margin of one meter in each direction. The communication cable runs above the power lines.

Distance to ground electrodes

The distance to the grounding conductors of high-voltage lines (bursts under the poles) is standardized: up to 1 kV - 1 meter; 1-35 kV – 5 meters; above 110 kV – 10 meters.

Cable trench

Cable laying practice

We painted the norms, now readers are probably interested in how the methods are implemented in practice. The depth of the trench for laying the cable is maintained by private traders approximately, a shovel will serve as a tool. Enterprises use tractors equipped with a harrow (cutter), bulldozers (removal of a wide layer). The cable snakes a little and goes in a slight wave. Helps compensate for temperature changes over the seasons. They try to put a large piece at once:

1. A system of rollers is mounted along the route, repeating the bends of the crooked bulldozer driver.
2. Horizontal drilling is being carried out under the highway and ravines with the cable channel exiting to the other side. HDPE pipes are laid inside. Some types of cable can be directly thrown to the bottom (mesh screen).
3. Sometimes concrete blocks are used to serve as channels.

A typical project shows the sequence of actions. Let’s say that a cable is laid in a trench inside a pipe by pulling the cable with a winch. The tension does not exceed 30 N/sq. mm aluminum and 50 N/sq. mm copper wires. A cross section of pure metal is taken and the area of ​​the braid is discarded. The length of the cable section pulled by the winch is estimated, and the friction forces and load are calculated according to the coefficients. Typical examples of numbers:

• The coefficient of friction when moving on rollers is 0.2-0.3
• When pulled into a concrete box - 0.4-0.6.
• When pulling the HDPE pipe inside, it is determined by the technique (reducing the coefficient, using lubricant, oil, water). It fluctuates between 0.1 – 0.25.

The load of three braided cables is calculated by the ratio as if one were stretching. No one can guarantee that the lengths of the elements are exactly the same. In practice it is difficult to achieve. The curvature radius of a single cable must be greater than 15 diameters of the outer insulation. For three-wire cables – 12. It is not enough to learn the types of cable laying trenches and read the PUE. You will need to study many norms, standards, rules, regulations.

Laying mutually redundant cables in a trench according to the PUE does not seem to be prohibited. But the introductory part says: it is prohibited to install lines in one sleeve. In the event of force majeure, simultaneous failure of both lines may occur (melt by an arc). The primary reason why joint laying of cables is not encouraged.

We conclude the review; we hope that we have explained how to use the documents. You can’t provide advice on entire life situations. Practical examples were taken, projects were implemented and put into operation. You shouldn't take advantage of loopholes in the law too much. Suddenly they change!

When laying cable lines directly in the ground, the cables must be laid in trenches and have a backfill on the bottom and a layer of fine earth on top that does not contain stones, construction waste and slag.

Cables along their entire length must be protected from mechanical damage by covering them at voltages of 35 kV and above with reinforced concrete slabs with a thickness of at least 50 mm; at voltages below 35 kV - with slabs or ordinary clay bricks in one layer across the cable route; when digging a trench with an earth-moving mechanism with a cutter width of less than 250 mm, as well as for one cable - along the cable line route. The use of silicate, as well as clay hollow or perforated bricks is not allowed.

When laid at a depth of 1-1.2 m, cables of 20 kV and below (except for city power supply cables) may not be protected from mechanical damage.

Cables up to 1 kV should have such protection only in areas where mechanical damage is likely (for example, in places of frequent excavation). Asphalt surfaces of streets, etc. are considered as places where digging is carried out in rare cases. For cable lines up to 20 kV, except for lines above 1 kV that supply power receivers of category I*, it is allowed in trenches with no more than two cable lines to use signal plastic tapes instead of bricks that meet the technical requirements approved by the USSR Ministry of Energy. It is not allowed to use warning tapes at the intersections of cable lines with utility lines and above cable couplings at a distance of 2 m in each direction from the crossed utility line or coupling, as well as at the approaches of lines to switchgears and substations within a radius of 5 m.

* According to local conditions, with the consent of the line owner, it is allowed to expand the scope of application of signal tapes.

The signal tape should be laid in a trench above the cables at a distance of 250 mm from their outer covers. When placing one cable in a trench, the tape must be laid along the axis of the cable; with a larger number of cables, the edges of the tape must protrude beyond the outer cables by at least 50 mm. When laying more than one tape across the width of a trench, adjacent tapes must be laid with an overlap of at least 50 mm wide.

When using signal tape, laying cables in a trench with a cable cushion, sprinkling the cables with the first layer of earth and laying the tape, including sprinkling the tape with a layer of earth along the entire length, must be carried out in the presence of a representative of the electrical installation organization and the owner of the electrical networks.

2.3.84

The depth of cable lines from the planning mark must be no less than: lines up to 20 kV 0.7 m; 35 kV 1 m; when crossing streets and squares, regardless of voltage 1 m.

Oil-filled cable lines 110-220 kV must have a laying depth from the planning mark of at least 1.5 m.

It is allowed to reduce the depth to 0.5 m in sections up to 5 m long when entering lines into buildings, as well as where they intersect with underground structures, provided that the cables are protected from mechanical damage (for example, laying in pipes).

The laying of 6-10 kV cable lines across arable land must be done at a depth of at least 1 m, while the strip of land above the route can be occupied for crops.

2.3.85

The clear distance from a cable laid directly in the ground to the foundations of buildings and structures must be at least 0.6 m. Laying cables directly in the ground under the foundations of buildings and structures is not allowed. When laying transit cables in basements and technical undergrounds of residential and public buildings, one should be guided by the SNiP of the Gosstroy of Russia.

2.3.86

When laying cable lines in parallel, the horizontal clear distance between the cables must be at least:

1) 100 mm between power cables up to 10 kV, as well as between them and control cables;

2) 250 mm between 20-35 kV cables and between them and other cables;

3) 500 mm* between cables operated by different organizations, as well as between power cables and communication cables;

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4) 500 mm between oil-filled cables 110-220 kV and other cables; in this case, low-pressure oil-filled cable lines are separated from one another and from other cables by reinforced concrete slabs placed on edge; in addition, the electromagnetic influence on communication cables should be calculated.

It is allowed, if necessary, by agreement between operating organizations, taking into account local conditions, to reduce the distances specified in clauses 2 and 3 to 100 mm, and between power cables up to 10 kV and communication cables, except for cables with circuits sealed by high-frequency telephone communication systems, up to 250 mm, provided that the cables are protected from damage that may occur during a short circuit in one of the cables (laying in pipes, installing fireproof partitions, etc.).

The distance between control cables is not standardized.

2.3.87

When laying cable lines in the plantation zone, the distance from the cables to the tree trunks should, as a rule, be at least 2 m. It is allowed, in agreement with the organization in charge of the green spaces, to reduce this distance, provided that the cables are laid in pipes laid by digging .

When laying cables within a green area with shrub plantings, the specified distances can be reduced to 0.75 m.

2.3.88

When laying in parallel, the horizontal clear distance from cable lines with voltages up to 35 kV and oil-filled cable lines to pipelines, water supply, sewerage and drainage must be at least 1 m; to gas pipelines of low (0.0049 MPa), medium (0.294 MPa) and high pressure (more than 0.294 to 0.588 MPa) - at least 1 m; to high pressure gas pipelines (more than 0.588 to 1.176 MPa) - at least 2 m; to heat pipelines - see 2.3.89.

In cramped conditions, it is allowed to reduce the specified distances for cable lines to 35 kV, with the exception of distances to pipelines with flammable liquids and gases, to 0.5 m without special cable protection and to 0.25 m when laying cables in pipes. For oil-filled cable lines 110-220 kV in a convergence section with a length of no more than 50 m, it is allowed to reduce the horizontal clear distance to pipelines, with the exception of pipelines with flammable liquids and gases, to 0.5 m, provided that a protective wall is installed between the oil-filled cables and the pipeline , eliminating the possibility of mechanical damage. Parallel laying of cables above and below pipelines is not permitted.

2.3.89

When laying a cable line parallel to a heat pipe, the clear distance between the cable and the wall of the heat pipe channel must be at least 2 m, or the heat pipe throughout the entire area of ​​proximity to the cable line must have such thermal insulation so that additional heating of the ground by the heat pipe in the place where the cables pass does not occur at any time of the year. exceeded 10°C for cable lines up to 10 kV and 5°C for lines 20-220 kV.

2.3.90

When laying a cable line parallel to railways, the cables must, as a rule, be laid outside the road exclusion zone. Laying cables within the exclusion zone is allowed only in agreement with organizations of the Ministry of Railways, and the distance from the cable to the axis of the railway track must be at least 3.25 m, and for an electrified road - at least 10.75 m. In cramped conditions It is permissible to reduce the specified distances, while the cables throughout the approach area must be laid in blocks or pipes.

For electrified roads running on direct current, the blocks or pipes must be insulating (asbestos-cement, impregnated with tar or bitumen, etc.)*.

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2.3.91

When laying a cable line parallel to tram tracks, the distance from the cable to the axis of the tram track must be at least 2.75 m. In cramped conditions, this distance can be reduced, provided that the cables throughout the approach area will be laid in insulating blocks or pipes specified in 2.3.90.

2.3.92

When laying a cable line parallel to highways of categories I and II (see 2.5.145), the cables must be laid on the outside of the ditch or the bottom of the embankment at a distance of at least 1 m from the edge or at least 1.5 m from the curb stone. Reducing the specified distance is allowed in each individual case in agreement with the relevant road departments.

2.3.93

When laying a cable line in parallel with an overhead line of 110 kV and above, the distance from the cable to the vertical plane passing through the outermost wire of the line must be at least 10 m.

The clear distance from the cable line to the grounded parts and grounding conductors of overhead line supports above 1 kV must be at least 5 m at voltages up to 35 kV, 10 m at voltages of 110 kV and above. In cramped conditions, the distance from cable lines to underground parts and grounding conductors of individual overhead line supports above 1 kV is allowed at least 2 m; in this case, the distance from the cable to the vertical plane passing through the overhead line wire is not standardized.

The clear distance from the cable line to the overhead line support up to 1 kV must be at least 1 m, and when laying the cable in the approach area in an insulating pipe, 0.5 m.

In the territories of power plants and substations in cramped conditions, it is allowed to lay cable lines at distances of at least 0.5 m from the underground part of overhead communication supports (current conductors) and overhead lines above 1 kV, if the grounding devices of these supports are connected to the grounding loop of the substations.

2.3.94

*. When cable lines cross other cables, they must be separated by a layer of earth at least 0.5 m thick; this distance in cramped conditions for cables up to 35 kV can be reduced to 0.15 m, provided that the cables are separated throughout the entire intersection area plus 1 m in each direction with slabs or pipes made of concrete or other equal strength material; in this case, communication cables must be located above power cables.

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* Agreed with the USSR Ministry of Communications.

2.3.95

When cable lines cross pipelines, including oil and gas pipelines, the distance between the cables and the pipeline must be at least 0.5 m. This distance can be reduced to 0.25 m, provided that the cable is laid at the intersection plus at least 2 m in each direction in pipes.

When an oil-filled cable line crosses pipelines, the clear distance between them must be at least 1 m. For cramped conditions, a distance of at least 0.25 m is allowed, but provided that the cables are placed in pipes or reinforced concrete trays with a lid.

2.3.96

When cable lines up to 35 kV cross heat pipes, the distance between the cables and the ceiling of the heat pipe in the clear must be at least 0.5 m, and in cramped conditions - at least 0.25 m. In this case, the heat pipe at the intersection plus 2 m in each direction from the outer cables must have such thermal insulation that the temperature of the ground does not increase by more than 10 ° C in relation to the highest summer temperature and by 15 ° C in relation to the lowest winter temperature.

In cases where the specified conditions cannot be met, one of the following measures is allowed: deepening the cables to 0.5 m instead of 0.7 m (see 2.3.84); use of a cable insert with a larger cross-section; laying cables under the heat pipeline in pipes at a distance of at least 0.5 m from it, while the pipes must be laid in such a way that cable replacement can be done without excavation work (for example, inserting pipe ends into chambers).

When an oil-filled cable line crosses a heat pipe, the distance between the cables and the ceiling of the heat pipe must be at least 1 m, and in cramped conditions - at least 0.5 m. In this case, the heat pipe at the intersection plus 3 m in each direction from the outermost cables must have such thermal insulation so that the ground temperature does not rise by more than 5°C at any time of the year.

2.3.97

When cable lines cross railways and highways, the cables must be laid in tunnels, blocks or pipes across the entire width of the exclusion zone at a depth of at least 1 m from the roadbed and at least 0.5 m from the bottom of drainage ditches. In the absence of an exclusion zone, the specified laying conditions must be met only at the intersection plus 2 m on both sides of the road surface.

When cable lines cross electrified and subject to direct current* railways, the blocks and pipes must be insulating (see 2.3.90). The intersection must be at a distance of at least 10 m from the arrows, crosses and points of connection of suction cables to the rails. The intersection of cables with the tracks of electrified rail transport should be made at an angle of 75-90° to the axis of the track.

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* Agreed with the Ministry of Railways.

The ends of blocks and pipes must be recessed with jute braided cords coated with waterproof (crumpled) clay to a depth of at least 300 mm.

When crossing dead-end industrial roads with low traffic intensity, as well as special paths (for example, on slips, etc.), cables, as a rule, should be laid directly in the ground.

When the route of cable lines crosses a newly constructed non-electrified railway or highway, relocation of existing cable lines is not required. At the intersection, reserve blocks or pipes with tightly sealed ends should be laid in the required quantity in case of cable repairs.

In the case of a transition of a cable line into an overhead line, the cable must exit to the surface at a distance of at least 3.5 m from the base of the embankment or from the edge of the canvas.

2.3.98

When cable lines cross tram tracks, the cables must be laid in insulating blocks or pipes (see 2.3.90). The intersection must be carried out at a distance of at least 3 m from the switches, crosses and points of connection of suction cables to the rails.

2.3.99

When cable lines cross vehicle entrances to courtyards, garages, etc., cables must be laid in pipes. Cables at intersections of streams and ditches should be protected in the same way.

2.3.100

When installing cable boxes on cable lines, the clear distance between the cable box body and the nearest cable must be at least 250 mm.

When laying cable lines on steeply inclined routes, installing cable couplings on them is not recommended. If it is necessary to install cable joints in such areas, horizontal platforms must be made underneath them.

To ensure the possibility of reinstalling the couplings in the event of their damage on the cable line, it is necessary to lay the cable on both sides of the couplings with a reserve.

2.3.101

If there are stray currents of dangerous quantities along the cable line route, it is necessary to:

1. Change the cable line route in order to bypass dangerous areas.

2. If it is impossible to change the route: provide measures to minimize the levels of stray currents; use cables with increased resistance to corrosion; carry out active protection of cables from the effects of electrocorrosion.

When laying cables in aggressive soils and areas with stray currents of unacceptable values, cathodic polarization must be used (installation of electrical drains, protectors, cathodic protection). For any methods of connecting electrical drainage devices, the norms for potential differences in the suction areas provided for #M12291 871001027SNiP 3.04.03-85 #S "Protection of building structures and structures from corrosion" of the State Construction Committee of Russia. It is not recommended to use cathodic protection with external current on cables laid in saline soils or saline bodies of water.

The need to protect cable lines from corrosion should be determined based on the combined data of electrical measurements and chemical analyzes of soil samples. Protection of cable lines from corrosion should not create conditions that are dangerous for the operation of adjacent underground structures. The designed corrosion protection measures must be implemented before the new cable line is put into operation. If there are stray currents in the ground, it is necessary to install control points on cable lines in places and at distances that make it possible to determine the boundaries of dangerous zones, which is necessary for the subsequent rational selection and placement of protective equipment.

To control potentials on cable lines, it is allowed to use the places where cables exit to transformer substations, distribution points, etc.