Power supply reliability categories according to PUE 7

General requirements. Electricity supply

7.1.13. Electrical receivers must be powered from a 380/220 V network with a TN-S or TN-CS grounding system.

When reconstructing residential and public buildings with a network voltage of 220/127 V or 3x220 V, the network should be switched to a voltage of 380/220 V with a TN-S or TN-CS grounding system.

7.1.14. External power supply to buildings must meet the requirements of Ch. 1.2.

7.1.15. In dormitories of various institutions, in schools and other educational institutions, etc. the construction of built-in and attached substations is not allowed.

In residential buildings, in exceptional cases, it is allowed to place built-in and attached substations using dry-type transformers in agreement with state supervisory authorities, while sanitary requirements for limiting noise and vibration levels must be fully met in accordance with current standards.

The construction and placement of built-in, attached and free-standing substations must be carried out in accordance with the requirements of the chapters of Section. 4.

7.1.16. It is recommended that power and lighting electrical receivers be powered from the same transformers.

7.1.17. The location and layout of transformer substations must provide for the possibility of round-the-clock unhindered access to them for personnel of the energy supply organization.

7.1.18. Power supply for safety lighting and evacuation lighting must be carried out in accordance with the requirements of Chapter. 6.1 and 6.2, as well as SNiP 23-05-95 “Natural and artificial lighting”.

7.1.19. If there are elevators in the building, which are also intended for transporting fire departments, their power supply must be provided in accordance with the requirements of Chapter. 7.8.

7.1.20. Electrical networks of buildings must be designed to power advertising lighting, shop windows, facades, illumination, outdoor, fire-fighting devices, dispatch systems, local television networks, light indicators of fire hydrants, safety signs, bell and other alarms, light fencing lights, etc., in in accordance with the design specifications.

7.1.21. When supplying single-phase consumers of buildings from a multiphase distribution network, it is allowed for different groups of single-phase consumers to have common N and PE conductors (five-wire network) laid directly from the ASU; combining N and PE conductors (four-wire network with PEN conductor) is not allowed.

When supplying single-phase consumers from a multiphase supply network with branches from overhead lines, when the PEN conductor of the overhead line is common to groups of single-phase consumers powered from different phases, it is recommended to provide protective shutdown of consumers when the voltage exceeds the permissible limit, arising due to load asymmetry when the PEN breaks conductor. The disconnection must be carried out at the entrance to the building, for example, by influencing the independent release of the input circuit breaker using a maximum voltage relay, and both the phase (L) and neutral working (N) conductors must be disconnected.

When choosing devices and devices installed at the input, preference, other things being equal, should be given to devices and devices that remain operational when the voltage exceeds the permissible voltage, arising due to load asymmetry when the PEN or N conductor breaks, while their switching and other operating characteristics may not be fulfilled.

In all cases, it is prohibited to have switching contact and non-contact elements in PE and PEN conductor circuits.

Connections that can be disassembled with a tool are allowed, as well as connectors specially designed for this purpose.

Categories of power supply reliability according to PUE

• residential premises equipped with electric stoves;
• residential premises on 6 or more floors, equipped with gas stoves;
• dormitories housing 50 or more people;
• enterprises and organizations employing from fifty to 2 thousand people;
• pharmacies, as well as medical institutions;
• institutions for children;
• sports facilities with a covering for 300-800 seats;
• sports facilities without cover, with at least 20 rows;
• catering establishments with 100-500 seats;
• retail outlets with a trading area of ​​250-2021 m2;
• laundries, baths and dry cleaners;
• organizations involved in servicing city transport;
• studios and household factories with at least 50 jobs;
• hairdressing and beauty salons for at least 10 jobs;
• pumping stations for water pipelines in settlements from 50 to 50 thousand people;
• pumping stations for sewerage with the possibility of emergency release at least once a day, structures for sewerage and water supply systems;
• educational institutions for 200-1000 people;
• buildings housing exhibitions and museums of local importance;
• hotels with 200-1000 beds;
• libraries and archival organizations, where they charge from 10 thousand to 1 million units;
• laboratories, as well as centers conducting calculations;
• central heating centers located in microdistricts;
• dispatch centers located in residential areas;
• lighting installations for roads and tunnels;
• Transformer substations and central processing centers in cities with a total load of 400 to 10 thousand kV•A.

• medical institutions, where even a short absence of electricity can cause death to patients;
• fire-fighting equipment in medical institutions;
• boiler houses, which are the main source of heat for category 1 consumers;
• make-up, as well as network pumps in boiler houses, which belong to category 2 and are equipped with hot water boilers with a capacity of more than 10 Gcal/h;
• pumping stations for water pipelines supplying settlements with a population of more than 50,000 people;
• pumping stations for sewerage that have emergency release at least once every 2 days;
• pumping artesian wells of 3 categories that work for the general water supply network;
• emergency or evacuation equipment, elevators, consisting of at least 17 floors;
• fire protection systems, alarms, elevators in premises with a height of at least 17 floors, institutions where at least 2 thousand people work and hotels with 1 thousand beds;
• institutions financed by union or republican organizations;
• libraries and archives , where the collection is approximately 100 thousand items;
• exhibitions, museums of regional importance, as well as alarm and fire protection systems in these buildings;
• fire-fighting devices in educational institutions where at least 1 thousand people are trained;
• fire protection systems, fire pumps, emergency and evacuation equipment in sports buildings with 800 seats;
• catering establishments with at least 500 seats;
• alarm and fire-fighting equipment in stores with an area of ​​at least 2 thousand m2;
• traction systems for power supply of category 3 for electric transport in the city;
• computer centers performing tasks , processes and problems of category 1;
• points for dispatchers in gas supply networks, electrical networks, lighting and water management networks;
• centralized security;
• heating points that serve buildings with 17 or more floors;
• CPUs in cities with a total load of at least 10 thousand kV•A.

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Grounding and grounding

7.3.132. Explosive zones of any class indoors and outdoor explosive installations are subject to the requirements given in 1.7.38 regarding the admissibility of using a solidly grounded or insulated neutral in electrical installations up to 1 kV. With an isolated neutral, automatic control of the network insulation must be provided with an effect on the signal and monitoring of the serviceability of the breakdown fuse.

7.3.133. In hazardous areas of classes BI, B-Ia and B-II, it is recommended to use protective shutdown (see Chapter 1.7). In hazardous areas of any class, potential equalization must be performed in accordance with 1.7.47.

7.3.134. In explosive zones of any class, the following must also be grounded (grounded):

a) as amended by 1.7.33 - electrical installations at all AC and DC voltages;

b) electrical equipment installed on neutralized (grounded) metal structures, which in accordance with 1.7.48, paragraph 1 in non-explosive areas are allowed not to be neutralized (not grounded). This requirement does not apply to electrical equipment installed inside neutralized (grounded) cabinets and control panels.

Conductors specially designed for this purpose must be used as neutral protective (grounding) conductors.

7.3.135. In electrical installations up to 1 kV with a solidly grounded neutral, grounding of electrical equipment must be carried out:

a) in power networks in explosive areas of any class of a separate residential cable or wire;

b) in lighting networks in explosive zones of any class, except for class BI, - in the area from the luminaire to the nearest branch box - with a separate conductor connected to the neutral working conductor in the branch box;

c) in lighting networks in an explosive zone of class BI - with a separate conductor laid from the luminaire to the nearest group panel;

d) on the network section from the switchgear and transformer substations located outside the explosive zone to the switchboard, assembly, distribution point, etc., also located outside the explosive zone, from which power is supplied to electrical receivers located in explosive zones of any class, is allowed as For the neutral protective conductor, use the aluminum sheath of the power cables.

7.3.136. Neutral protective conductors in all parts of the network must be laid in common shells, pipes, boxes, bundles with phase conductors.

7.3.137. In electrical installations up to 1 kV and higher with an insulated neutral, grounding conductors can be laid either in a common shell with phase conductors or separately from them.

Grounding lines must be connected to grounding conductors in two or more different places and, if possible, from opposite ends of the room.

7.3.138. The use of metal building structures, industrial structures, steel electrical wiring pipes, metal cable sheaths, etc. as neutral protective (grounding) conductors is allowed only as an additional measure.

7.3.139. In electrical installations up to 1 kV with a solidly grounded neutral, in order to ensure automatic shutdown of the emergency section, the conductivity of the neutral protective conductors must be selected such that, in the event of a short circuit to the housing or neutral protective conductor, a short-circuit current occurs that is at least 4 times greater than the rated current of the fuse link of the nearest fuse and at least 6 times the current of the circuit breaker release, which has an inverse current characteristic.

When protecting networks with automatic circuit breakers that have only an electromagnetic release (without a time delay), you should be guided by the requirements regarding the short-circuit current multiplicity and given in 1.7.79.

7.3.140. A calculated check of the impedance of the phase-zero loop in electrical installations with voltages up to 1 kV with a solidly grounded neutral must be provided for all electrical receivers located in explosive zones of classes BI and B-II, and selectively (but not less than 10% of the total number) for electrical receivers located in explosive zones of classes B-Ia, B-Ib, B-Ig and BIIa and having the highest phase-zero loop resistance.

7.3.141. Passages of specially laid neutral protective (grounding) conductors through the walls of rooms with explosive zones must be made in pipe sections or in openings. The openings of pipes and openings must be sealed with non-combustible materials. The connection of neutral protective (grounding) conductors in passage areas is not allowed.

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PUE status?

— Partially valid (not all articles are approved by the federal executive authority), reference (since it is not a document in the field of standardization under the Federal Law on TR, and only technical regulations of the Customs Union or the Russian Federation are mandatory), the procedure for application is not defined .

In Appendix 2 to the order of OJSC RAO <> dated 08/14/2003 N. 422, “List of scientific and technical documentation approved in ministries and departments of the Russian Federation before 07/01/2003, subject to mandatory execution,” the document is listed under N. 28.

according to the Register of scientific and technical documentation operating in the electric power industry in accordance with Appendix 1 to the order of OJSC RAO <> dated 08/14/2003 No. 422 document is listed under No.580.

Has identification number: SO 153-34.20.120-2003

Name: Rules for the installation of electrical installations (Section 6, Chapter 7.1 and 7.2 - Approved by Order of the Minister of Energy of the Russian Federation dated 06.10.1999; Chapters 1.1, 1.2, 1.7, 1.9, 7.5, 7.6, 7.10 - Approved by Order of the Minister of Energy of the Russian Federation dated 08.07. 2002 No. 204; Chapters 2.4, 2.5 - Approved by the Minister of the Ministry of Energy of the Russian Federation dated May 20, 2003 No. 187; Chapters 4.1,

4.2 - Approved Minister of the Ministry of Energy of the Russian Federation dated June 20, 2003 No. 242; Chapter 1.8 - Approved.

Minister of the Ministry of Energy of the Russian Federation dated 04/09/2003 No. 150) In the order of the Federal Service for Environmental, Technological and Nuclear Supervision dated July 28, 2011 No. 435 “On approval of section I <> List of normative legal acts and normative documents related to the scope of activity of the Federal Service for Environmental, Technological and Nuclear Supervision as of July 1, 2011” PUE is listed for use in current activities to the extent that does not contradict the law Russian Federation, in subsection IV. Regulatory legal acts and regulatory documents of federal executive authorities, regulatory documents of executive authorities (divisions of executive authorities) of the USSR and the RSFSR”, in paragraph 5.

“Safety of electrical and thermal installations and networks”, subclause 5.2.

"Safety of Electrical Installations and Networks", No. 5.2.54.

But, besides this, I would like to note that:

1 From 2008 to the present, about 47 STO 70238424 have been approved and put into effect. ... series “Conditions for creation” (read design rules) of specific electrical equipment, systems, devices, stations, substations, power lines, etc. . and about a dozen STO 56947007-... relating to design standards and creation conditions.

2 According to the Federal Law of the Russian Federation dated December 27, 2002 N 184-FZ “On

technical regulation" PUE cannot be classified (attributed) to documents in the field of standardization (status is not defined).

3 Recent changes that removed from the scope of the Federal Law of the Russian Federation dated December 27, 2002 N 184-FZ “On Technical Regulation” “... relations related to the development, adoption, application and implementation ... of requirements for ensuring the reliability and safety of electric power systems and electric power facilities , with the exception of cases of development, adoption, application and execution of such requirements for products or for products and the processes of design (including research), production, construction, installation, commissioning, operation, storage, transportation, sales and disposal related to the requirements for products.” (the status of the PUE is even more uncertain).

4 Latest Amendments to the Federal Law of March 26, 2003 N 35-FZ “On Electric Power Industry” The Government of the Russian Federation (the Ministry of Energy in particular) does not have the authority to determine (approve) the rules for the design of electrical installations and the rules for the technical operation of power plants and networks.

Powers of the Government of the Russian Federation in the field of state regulation and control in the electric power industry The Government of the Russian Federation, federal executive authorities and executive authorities of the constituent entities of the Russian Federation in accordance with the legislation of the Russian Federation on the electric power industry are authorized to:

- approve:

rules of the wholesale market and basic provisions for the functioning of retail markets; essential terms of the agreement on joining the trading system of the wholesale electricity and capacity market; the procedure for the development, coordination and approval of schemes and programs for the development of a unified national (all-Russian) electric network for a long-term period, rules of non-discriminatory access to electric energy transmission services, operational dispatch control services in the electric power industry and services of commercial infrastructure organizations; rules for the provision of services for the transmission of electric energy, for operational dispatch control in the electric power industry and services for commercial infrastructure organizations; rules for the implementation of antimonopoly regulation and control in the electric power industry; sample contracts for the purchase and sale of electrical energy (energy supply) with consumers; rules of operational dispatch control in the electric power industry, including a list of technologically isolated territorial electric power systems, a list of subjects of operational dispatch control in these systems and the procedure for implementing operational dispatch control in them; rules for concluding and executing public contracts on the wholesale and retail markets; rules and procedures for guaranteeing suppliers; the procedure for providing intersystem electrical connections, including the methodology for carrying out mutual settlements related to the settlement of relations regarding the transmission of electrical energy; procedure for investigating the causes of accidents in the electric power industry; the procedure for the creation and functioning of headquarters to ensure the safety of power supply in order to prevent disruption of power supply for reasons beyond the control of the actions of power industry entities and caused, along with other reasons, by dangerous natural phenomena or other emergency situations; the main directions of state policy in the field of increasing the energy efficiency of the electric power industry, containing target indicators for the volume of production and consumption of electrical energy using renewable energy sources in the total balance of production and consumption of electrical energy; a plan or program of activities to achieve the specified targets; criteria for providing subsidies from the federal budget in order to compensate for the cost of technological connection of generating facilities with an installed generating capacity of no more than 25 MW, recognized as qualified facilities in accordance with the provisions of paragraph 3 of Article 33 of this Federal Law, operating on the basis of the use of renewable energy sources, to persons who such objects belong by right of ownership or other legal basis; rules for the technological functioning of electric power systems;

- determine:

procedure and conditions for the construction and financing of electric power facilities; the procedure for decommissioning electrical power facilities for repairs and decommissioning; the procedure for interaction between subjects of operational dispatch control in the electric power industry and grid organizations that carry out operational and technological control; features of the forced separation of business entities carrying out monopolistic activities in the electric power industry; essential terms of agreements on the procedure for the use by the organization for managing the unified national (all-Russian) electrical network of power grid facilities belonging to the owners or other legal owners and included in the unified national (all-Russian) electrical network; the procedure for complete and (or) partial limitation of the mode of consumption of electrical energy, including its level, in the event of violation of their obligations by consumers of electrical energy (including in relation to certain categories of consumers for whom a special procedure may be provided for providing security for obligations to pay for electrical energy ), as well as if it is necessary to take urgent measures to prevent or eliminate accidents; a list of individual parts of the price zones of the wholesale market, which establish the features of the functioning of the wholesale and retail markets; and change the boundaries of price and non-price zones of the wholesale market, taking into account the technological and systemic limitations of the Unified Energy System of Russia; the main directions of state policy in the field of energy saving; a mechanism for stimulating the use of renewable energy sources by selling electrical energy produced by qualified generating facilities operating on their basis on the wholesale market at equilibrium prices of the wholesale market, taking into account a premium determined in the manner established by the Government of the Russian Federation, or by selling the capacity of qualified generating facilities in the amount production of electrical energy based on the use of renewable energy sources using the capacity trading mechanism provided for by the rules of the wholesale market for the sale of capacity of the specified generating facilities.

- install:

criteria and procedure for classifying electrical grid facilities as part of the unified national (all-Russian) electrical network; the procedure for technological connection of power receiving devices of legal entities and individuals to electrical networks; rules for the provision of services to ensure system reliability, services to ensure the recovery of the Unified Energy System of Russia from emergency situations, services to form a technological power reserve; criteria and procedure for classifying subjects of the electric power industry and consumers of electric energy as persons subject to mandatory servicing when providing services for operational dispatch control in the electric power industry; criteria for classifying electric power industry entities as entities whose investment programs (including determining the sources of their

financing) are approved by the authorized federal executive body and (or) executive bodies of the constituent entities of the Russian Federation; the procedure for approving (including the procedure for coordination with executive authorities of the constituent entities of the Russian Federation) investment programs and monitoring the implementation of such programs; features of the functioning of the wholesale and retail markets in certain parts of the price zones of the wholesale market, the procedure for submitting price applications by subjects of the wholesale market, the procedure for their selection and determination of the equilibrium price of the wholesale market, taking into account the characteristics of its price zones; rules for maintaining mandatory separate accounting by type of activity in the electric power industry; rules, criteria and procedure for qualifying a generating facility operating on the basis of the use of renewable energy sources as meeting the target indicators established in accordance with the main directions of state policy in the field of increasing energy efficiency of the electric power industry (hereinafter referred to as qualified generating facilities operating on the basis of the use of renewable energy sources) . Generating facilities operating on the basis of the use of renewable energy sources also include facilities that carry out combined generation of electrical and thermal energy, if these facilities use renewable energy sources to generate electrical and thermal energy; the procedure for coordinating the transfer of electric grid facilities included in the unified national (all-Russian) electric grid to lease to territorial grid organizations; procedure for federal state energy supervision;

take measures for social protection of certain categories of citizens, including in the form of approving the procedure for providing such citizens with security for their obligations to pay for electric energy in accordance with the budgetary legislation of the Russian Federation;

support the use of renewable energy sources and stimulate the use of energy efficient technologies in accordance with the budget legislation of the Russian Federation;

And according to Art. 38. “Guarantees of reliable supply of electrical energy to consumers”:

— responsibility to consumers of electrical energy for reliability

providing them with electrical energy and its quality in accordance with the requirements of technical regulations (which do not exist and their development is not envisaged in the near future within the framework of the Customs Union) and other mandatory requirements (it is not clear what they are) bear (within their

responsibility) subjects of the electric power industry that ensure the supply of electric energy to consumers of electric energy, including energy sales organizations, guaranteeing suppliers and territorial network organizations;

— the basis of the system for reliable provision of electrical energy to consumers is a reliable power supply scheme and compliance with all requirements of the rules of technical operation of power plants and networks, as well as the presence of specialized organizations in the retail markets - guaranteeing suppliers.

Sincerely,

Head of the Technical Regulation Department of the Department of Regulatory and Technical Policy of NP "INVEL"

Ganin Vyacheslav Sergeevich

Grounding devices

1.8.36. Grounding devices are tested to the extent provided for in this paragraph.

1. Checking the elements of the grounding device. This should be done by inspecting the elements of the grounding device within the scope of inspection. The cross-sections and conductivity of the elements of the grounding device must comply with the requirements of these Rules and design data.

2. Checking the circuit between grounding conductors and grounding elements. You should check the cross-sections, integrity and strength of the grounding and grounding conductors, their connections and connections. There should be no breaks or visible defects in the grounding conductors connecting the devices to the grounding loop. The reliability of welding is checked by hitting a hammer.

3. Checking the condition of breakdown fuses in electrical installations up to 1 kV. Breakdown fuses must be in good working order and correspond to the rated voltage of the electrical installation.

4. Checking the phase-zero circuit in electrical installations up to 1 kV with solid neutral grounding. The check should be carried out in one of the following ways: by directly measuring the current of a single-phase fault to the housing or wire using special instruments; by measuring the impedance of the phase-zero loop with subsequent calculation of the single-phase fault current.

The current of a single-phase fault to the housing or neutral wire must ensure reliable operation of the protection, taking into account the coefficients given in the relevant chapters of these Rules.

5. Measuring the resistance of grounding devices. The resistance values ​​must comply with the values ​​given in the relevant chapters of these Rules.

PUE 7. Rules for electrical installations. Edition 7

1.1.1. The Rules for the Construction of Electrical Installations (PUE) apply to newly constructed and reconstructed electrical installations of direct and alternating current with voltage up to 750 kV, including special electrical installations discussed in Section 7 of these Rules.

The construction of special electrical installations not discussed in Section 7 must be regulated by other regulatory documents. Separate requirements of these Rules may be applied to such electrical installations to the extent that they are similar in design and operating conditions to the electrical installations discussed in these Rules.

The requirements of these Rules are recommended to be applied to existing electrical installations if this increases the reliability of the electrical installation or if its modernization is aimed at ensuring safety requirements.

In relation to reconstructed electrical installations, the requirements of these Rules apply only to the reconstructed part of the electrical installations.

1.1.2. PUEs are developed taking into account the obligatory conduct of scheduled preventive and maintenance tests, repairs of electrical installations and their electrical equipment under operating conditions.

1.1.3. An electrical installation is a set of machines, apparatus, lines and auxiliary equipment (together with the structures and premises in which they are installed) intended for the production, transformation, transformation, transmission, distribution of electrical energy and its conversion into other types of energy.

1.1.4. Open or outdoor electrical installations are electrical installations that are not protected by the building from atmospheric influences.

Electrical installations protected only by canopies, mesh fences, etc. are considered external.

Closed or internal electrical installations are electrical installations located inside a building that protects them from atmospheric influences.

1.1.5. Electrical rooms are rooms or fenced off (for example, nets) parts of the room in which electrical equipment is located, accessible only to qualified service personnel.

1.1.6. Dry rooms are rooms in which the relative air humidity does not exceed 60%.

If the conditions specified in 1.1.10-1.1.12 are absent in such premises, they are called normal.

1.1.7. Wet rooms are rooms in which the relative air humidity is more than 60%, but does not exceed 75%.

1.1.8. Damp rooms are rooms in which the relative air humidity exceeds 75%.

1.1.9. Particularly damp rooms are rooms in which the relative air humidity is close to 100% (the ceiling, walls, floor and objects in the room are covered with moisture).

1.1.10. Hot rooms are rooms in which, under the influence of various thermal radiation, the temperature constantly or periodically (more than 1 day) exceeds +35 ° C (for example, rooms with dryers, kilns, boiler rooms).

1.1.11. Dusty rooms are rooms in which, due to production conditions, process dust is released, which can settle on live parts and penetrate into machines, devices, etc.

Dusty rooms are divided into rooms with conductive dust and rooms with non-conductive dust.

1.1.12. Rooms with a chemically active or organic environment are rooms in which aggressive vapors, gases, liquids are constantly or for a long time contained, deposits or mold are formed that destroy the insulation and live parts of electrical equipment.

1.1.13. With regard to the danger of electric shock to people, the following are distinguished:

1) premises without increased danger, in which there are no conditions that create increased or special danger (see paragraphs 2 and 3);

2) premises with increased danger, characterized by the presence of one of the following conditions creating increased danger:

• dampness or conductive dust (see 1.1.8 and 1.1.11);
• conductive floors (metal, earthen, reinforced concrete, brick, etc.);
• high temperature (see 1.1.10);
• the possibility of simultaneous human contact with metal structures of buildings connected to the ground, technological devices, mechanisms, etc., on the one hand, and with metal casings of electrical equipment (exposed conductive parts), on the other;

3) especially dangerous premises, characterized by the presence of one of the following conditions creating a special danger:

• special dampness (see 1.1.9);
• chemically active or organic medium (see 1.1.12);
• simultaneously two or more conditions of increased danger (see 1.1.13, clause 2);

4) the territory of open electrical installations in relation to the danger of electric shock to people is equated to especially dangerous premises.

1.1.14. Qualified service personnel are specially trained workers who have passed a knowledge test to the extent required for this job (position), and have an electrical safety group provided for by the current labor protection rules when operating electrical installations.

1.1.15. The nominal value of a parameter is the value of a parameter of an electrical device specified by the manufacturer.

1.1.16. AC voltage is the effective value of voltage.

DC voltage - direct current voltage or rectified current voltage with a ripple content of no more than 10% of the effective value.

1.1.17. To indicate the mandatory compliance with the requirements of the PUE, the words “must”, “should”, “necessary” and derivatives from them are used. The words “as a rule” mean that this requirement is predominant, and deviation from it must be justified. The word “allowed” means that this decision is applied as an exception as forced (due to cramped conditions, limited resources of necessary equipment, materials, etc.). The word “recommended” means that this solution is one of the best, but not required. The word “may” means that the decision is lawful.

1.1.18. The standardized values ​​of quantities accepted in the PUE with the indication “not less” are the smallest, and those with the indication “no more” are the greatest.

All values ​​of quantities given in the Rules with the prepositions “from” and “to” should be understood as “inclusive”.

Marking

You need to know what color the ground wire is.
Typically, the ground wire, in the form of a separate conductor, is part of the stranded wire that powers an electrical appliance or outlet.

Thus, in a 1-phase network it will be the 3rd conductor, and in a 3-phase network it will be the 5th.

In this case, a special marking is provided for the grounding wire, which makes it possible to distinguish it from the phase or neutral conductors and thus prevents confusion when connecting:

1. Letter. PUEs require that the letters “PE” be applied to the insulation of the grounding wire. The same designation is provided for in international standards. Indication of the cross-sectional area, grade and material is optional.
2. Colored. Domestic and foreign standards specify a combination of yellow and green colors for the ground wire. Some foreign manufacturers of cable products designate such a core only in yellow or only in green.

In addition to grounding conductors, combined conductors are used, which simultaneously perform the functions of zero working and zero protective. They are designated by the letters “PEN” and a combination of blue with yellow or green. One color of the ground wire is the main one, the second is applied in the form of stripes at the ends.

Installation of the ground wire

Thus, it is quite simple to distinguish the ground wire from the neutral wire, which is marked with a blue color and the letter “N,” and from the phase wire (it has brown, black or white insulation, designated by the letter “L”). Color coding has simplified not only the installation of electrical systems, but also such tasks as finding and replacing burnt, broken or overloaded wires.

Some manufacturers paint the phase conductor in other colors: gray, purple, red, turquoise, pink, orange.

Please note that color coding cannot determine whether the network is 1-phase or 3-phase, or whether it is supplied with alternating or direct current. Thus, the cores and buses of DC networks (used in construction, electric transport, substations, etc.) are also painted in red (“+”), blue (“-”) and blue (zero bus) colors. In 3-phase networks, phases A, B and C are usually designated yellow, green and red, respectively.

The designation of cores in different colors is not used in all wires. So, in a 3-core cable of the PPV brand, which seems attractive due to its relatively low cost, you will not find yellow-green insulation, so it is very easy to confuse the cores when connecting.

Working ground

If the marking is not visible or missing, you can determine the grounding conductor in a wire connected to the network using a voltmeter: the voltage is measured between the phase conductor (it is determined by the phase indicator) and each of the two remaining ones. When the probe contacts the “ground”, the value on the device display will be higher than when it contacts “zero”.

You can also measure the voltage between the conductors being tested and any grounded device, for example, an electrical panel housing or a heating battery. If the core is zero, the device will show some small value; if it is “ground”, the display will display zero.

The phase indicator, which is used to determine the wire connected to the phase, is similar to a screwdriver, only on the handle there is a diode light bulb and a special contact (usually in the form of a ring under the light bulb). To determine the phase, you need to place your finger on this contact and at the same time the tip of a screwdriver on the conductor being tested. If it is energized, the light will light up.

It should be understood that connecting a consumer to a ground wire is not a sufficient safety condition. The wire itself, on the other side, must be connected to the ground loop.

A resident of an apartment in a city high-rise building only needs to find the appropriate contact in the distribution board, but the owner of a private house will have to create such a circuit himself.

Usually it consists of metal pins driven into the ground (in the form of an isosceles triangle) connected by reinforcement.

How to do it right

First, let's look at the shape of the ground electrode. The most popular is in the form of an equilateral triangle with pins hammered into the vertices. There is also a linear arrangement (the same three pieces, only in a line) and in the form of a contour - the pins are driven around the house in increments of about 1 meter (for houses with an area of ​​more than 100 sq. m). The pins are connected to each other by metal strips - metal bonding.

The most popular ground electrode model

Procedure

From the edge of the blind area of ​​the house to the installation site of the pin there must be at least 1.5 meters. In the selected area, they dig a trench in the form of an equilateral triangle with a side of 3 m. The depth of the trench is 70 cm, the width is 50-60 cm - so that it is convenient to cook. One of the peaks, usually located closer to the house, is connected to the house by a trench with a depth of at least 50 cm.

Digging a trench

At the vertices of the triangle, pins are hammered (a round rod or corner 3 m long). Leave about 10 cm above the bottom of the pit

Please note that the ground electrode is not brought to the surface of the earth. It is located 50-60 cm below ground level

A metal bond is welded to the protruding parts of the rods/corners - a strip of 40 * 4 mm. The created ground electrode is connected to the house with a metal strip (40*4 mm) or a round conductor (cross-section 10-16 mm2). The strip with the created metal triangle is also welded. When everything is ready, the welding areas are cleaned of slag and coated with an anti-corrosion compound (not paint).

Welded strip

After checking the grounding resistance (in general, it should not exceed 4 Ohms), the trenches are covered with earth. There should be no large stones or construction debris in the ground; the earth is compacted layer by layer.

At the entrance to the house, a bolt is welded to the metal strip from the ground electrode, to which a copper conductor in insulation is attached (traditionally the color of the ground wires is yellow with a green stripe) with a core cross-section of at least 4 mm2.

Grounding outlet near the wall of the house with a bolt welded at the end

In the electrical panel, the grounding is connected to a special bus. Moreover, only on a special platform, polished to a shine and lubricated with grease. From this bus, the “ground” is connected to each line that is distributed throughout the house. Moreover, wiring the “ground” with a separate conductor according to the PUE is unacceptable - only as part of a common cable. This means that if you have two-wire wiring, you will have to completely change it.

Why you can’t make separate groundings

Rewiring the entire house is, of course, time-consuming and expensive, but if you want to operate modern electrical appliances and household appliances without problems, it is necessary. Separately grounding certain outlets is ineffective and even dangerous. And that's why. The presence of two or more such devices sooner or later leads to the output of the equipment plugged into these sockets. The thing is that the resistance of the circuits depends on the condition of the soil in each specific place. In some situation, a potential difference occurs between two grounding devices, which leads to equipment failure or electrical injury.

How to properly make closed-type grounding in a private house without the help of specialists?

After the preparatory work stage, the turn of installation comes. At first glance, the usual task of driving grounding conductors into the ground can, at a minimum, result in damaged rolled metal. And all this is due to ignorance of the process technology.

It is important to properly sharpen the electrodes before driving. Experienced electricians already know how to properly make protective grounding in a private home - they recommend making the tip with a bevel of 30-35°

You need to retreat 40-45 mm from its edge and make a descent of about 45-50°. A channel, I-beam or T-beam may have several bevels; it is recommended to sharpen the rods by forging. The further process can be observed in the video; it consists of performing the following transitions:

• Using a bayonet shovel, dig an equilateral triangular trench with sides of 1.2 meters, as well as a ditch towards the building for laying a grounding bus. The depth of the trench is 50-70 cm.
• For ease of driving, you can drill holes up to 50 cm deep in the corners of the triangle.
• Using a sledgehammer or a hammer drill with a nozzle, hammer in the electrodes, leaving 20-30 cm above the surface of the bottom of the ditch.
• Using electric welding, it is good to weld metal strips to the protruding parts of the ground electrodes.
• Lay a strip connecting the corner of the contour and the foundation of the building, first bending it along the profile.
• Weld the grounding bar to the corner of the triangle. From the house side, weld a bolt to the strip to secure the copper wire.
• Treat welding areas with anti-corrosion paint or bitumen. Let the paint dry and bury the ditch.

Checking ground loop parameters

The final stage in organizing the system is considered to be measuring the resistance of the finished circuit, because high-quality protection is needed not only when using a city line, but also when connecting a backup power generator. This stage will indicate how correctly the protective grounding was done in a private house, and whether any errors were made during installation. Resistance can be determined in several ways:

• Using a 220 Volt electric lamp, connecting one contact to the phase and the other to the ground bus. A brightly burning light indicates a well-functioning system, while a dimly lit one forces you to check the reliability of the welds.
• Using a soil megohmmeter, which measures the resistance between the circuit elements and control electrodes driven into the ground to a depth of 15 and 20 meters from the ground to a depth of 50 cm.
• Using a tester in voltage meter state. The measurement values ​​“phase-zero” and “phase-ground” should not have a significant difference (no more than 10 units).

As such, the protection system does not require maintenance; it is enough to prevent excavation work in the contour area and moisten the soil in a timely manner. The ingress of aggressive substances is also not allowed, since they reduce the service life of the structure to 2-3 years.

Issues covered in the PUE

Grounding loop in a private house
The Rules for the Construction of Electrical Installations approved by the Ministry of Energy of the Russian Federation regulate the scope of application of protective equipment, grounding rules and the procedure for its arrangement.

This term refers to a set of metal parts that, when assembled, provide electrical contact between the devices and the ground. The document describes equipment grounding requirements, technical specifications and standards.

PUEs apply to the following objects:

1. Means of production. These include machine tools, lifts of all types for people and goods, refrigeration units, generators, electric motors, heaters, conveyors and other products installed on factory floors.
2. Electrical appliances for household and industrial use. The grounding of the transformer neutral is regulated according to the PUE, stabilizers, transformer substations, rectifiers and storage devices.
3. Residential and private houses, dachas and cottages. In old buildings, only grounding of cabinets is carried out according to the PUE. Connection of apartments with outlets is carried out individually at the initiative of the residents.
4. Pipelines that transport explosive and flammable materials - oil, gas, gasoline, diesel fuel, solvents.
5. Power line supports. It is necessary to ground structures made of metal, which is an excellent conductor of current. It is also necessary to equip concrete pillars with protective structures, the height of which does not exceed 6 m.
6. Metal towers for floodlights, antennas and observer placement. In addition, buildings are equipped with lightning rods.

In accordance with the PUE, the grounding loop must ensure guaranteed acceptance of electrical leakage under any conditions. For this purpose, installation standards in various types of soil have been developed.

Color

The colors of grounding single-core and multi-core wires must be the same. It is regulated by electrical installation rules. When grounding is carried out independently, and the wire is selected without taking into account the color, it is wrapped at the contact with two-color yellow-green electrical tape or plain green.

In old-type houses built before the rules were approved, the colors of the ground wires can be any color. In electrical distribution devices and panels they are blue, red, black, because no identification marks have been made before.

It can be difficult to identify a boring core in a common cable. In this case, a reasonable question arises: how to determine the ground wire.

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When looking for grounding in a three-wire wire, use a multimeter. One contact is connected to the phase, the other to the wire under test. If the arrow on the instrument scale shows less than 220 V, this is the required wire; a grounding loop can be connected to it.

Grounding and grounding

5.4.56. Grounding and grounding must be carried out in accordance with the requirements of Chapter. 1.7. It is considered sufficient if the parts to be grounded or neutralized are connected to the metal structures of the crane, and the continuity of the electrical circuit of the metal structures must be ensured. If the crane's electrical equipment is installed on its grounded metal structures and there are cleared and unpainted areas on the supporting surfaces to ensure electrical contact, then additional grounding is not required.

The crane runway rails must be securely connected at the joints (by welding, welding jumpers of sufficient cross-section, welding to metal crane beams) to one another to create a continuous electrical circuit. In electrical installations for which grounding or grounding is used as a protective measure, the rails of the crane runway must be grounded or grounded accordingly.

When installing a crane outdoors, the rails of the crane track must, in addition, be connected to each other and grounded, and to ground the rails, it is necessary to provide at least two grounding rods connected to the rails in different places.

5.4.57. When powering the crane with a cable, in addition to the requirement of 5.4.56, the requirements of Ch. 1.7, requirements for mobile electrical installations.

5.4.58. The body of the push-button control device of a crane controlled from the floor must be made of insulating material or grounded (zeroed) with at least two conductors. A cable on which a push-button device is suspended can be used as one of the conductors.

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Read with this

• How to check grounding
• Why is the grounding system TT (to its circuit) more dangerous than tn (to neutral)
• Concept and operating principle of protective grounding
• Gzsh. main ground bus
• Safety guarantee, or how to properly ground in a private home
• Where to get grounding in Khrushchev
• What color is phase and zero in electrical engineering?
• Features of the use of zero buses
• Pue 7. rules for electrical installations. edition 7
• Protective conductors (PE conductors)

What category of power supply reliability, according to the PUE, do educational institutions belong to?

1.2.18. Category I power receivers must be provided with electricity from two independent, mutually redundant power sources, and an interruption in their power supply in the event of a power failure from one of the power sources can be allowed only for the duration of automatic power restoration.

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If power supply redundancy cannot ensure the necessary continuity of the technological process or if power supply redundancy is not economically feasible, technological redundancy must be implemented, for example, by installing mutually redundant technological units, special devices for emergency shutdown of the technological process, operating in the event of a power supply failure.