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GOST R 50571­4­44­2011

GOST R 50571­4­44­2011 (IEC 60364­4­44: 2007) Group E08

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Electrical low­voltage

Part 4­44

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Safety requirements. Protection against voltage fluctuation and electromagnetic interference

Low­voltage electrical installations. Part 4­44. Safety requirements. Protection against voltagedisturbances and electromagnetic disturbances

ACS 91.140.50 OKS 3402

Introduced 2012­07­01

Foreword

Aims and principles of standardization in the Russian Federation established by the Federal Law ofDecember 27, 2002 N 184­F3 "On Technical Regulation", and rules for the application of nationalstandards of the Russian Federation ­ GOST 1.0­2004 "Standardization in the Russian Federation. Themain provisions"

For information about the standard

1 PREPARED Private educational institution of higher professional education "Moscow Institute ofEnergy and Energy Conservation" (LEU VPO "MIEE") on the basis of their own authentic Russiantranslation of the standard referred to in paragraph 4

2 Make the Technical Committee for Standardization TC 337 "Electrical installations of buildings"

3 APPROVED and put into effect by the Order of the Federal Agency for Technical Regulation andMetrology of September 22, 2011 N 329­Article

4 This standard is modified in relation to the international standard IEC 60364­4­44: 2007 * Edition 2"Electrical installations of buildings. Part 4­44. Protection for safety. Protection against voltagevariations and electromagnetic interference" (IEC 60364­4­ 44: 2007 "Low­voltage electricalinstallations ­ Part 4­44: Protection for safety ­ Protection against voltage disturbances andelectromagnetic disturbances"). ________________

* Access to international and foreign documents mentioned here and hereinafter can be obtained byclicking on the link. ­ Note manufacturer's database.

The name of this standard is changed with respect to the name of this international standard toconform to GOST R 1.5 (item 3.5).

The "Normative references" is presented in accordance with GOST R 1.5 and the correspondingreferences in the text of the standard in italics

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5 INSTEAD GOST 50571.18­2000, GOST R 50571.19­2000, GOST R 50571.20­2000

Information about changes to this standard shall be published in the annually issued InformationIndex "National standards", and the text changes and amendments ­ in a monthly published informationsigns "National Standards". In the case of revision (replacement) or cancellation of a notification of thestandard will be published in a monthly index published by the information, "national standards".Relevant information notice and the text is placed in the public information system ­ the official websiteof the Federal Agency for Technical Regulation and Metrology on the Internet

Introduction

This standard has been prepared by the direct application of the international standard IEC 60364­4­44: 2007 "Electrical installations of buildings. Part 4­44. Protection for safety. Protection against voltagevariations and electromagnetic interference" and is part of national standards GOST R 50571 LowVoltage installation.

The standard establishes requirements to ensure the protection of electrical equipment and consumeby:

­ Short­term (pulse) voltage surge that may occur in the low­voltage electrical installation duringthunderstorms and thereby switching surges in circuits with high inrush currents. The requirements arebased on the basic standard IEC 60664­1 "Insulation coordination for equipment within low­voltagesystems. Part 1: Principles, requirements and tests" about the ability of electrical equipment insulation towithstand short­term surge of certain values for each of the four categories in the standard powerconsumers;

­ Undervoltage;

­ Electromagnetic interference.

440.1 Scope

This standard applies to low­voltage electrical installation (hereinafter ­ plant) and establishesrequirements to ensure their safety in case of voltage variations and electromagnetic interference.

This standard does not apply to electricity distribution system user and systems for power generationand transmission for such systems (see. GOST R 50571.1, section 1), despite the fact that the surge andelectromagnetic interference can be transmitted to electrical or between electrical installations throughsuch systems .

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440.2 Normative references

In this standard references to the following regulatory standards.

GOST R 50571.1­2009 (IEC 60364­1: 2005) Electrical installations of low voltage. Part 1: Basicprovisions, assessment of general characteristics, terms and definitions

GOST R 50571.3­2009 (IEC 60364­4­41: 2005) Electrical installations of low voltage. Part 4­41.Requirements for safety. Protection against electric shock

GOST R 50571.10­96 (IEC 60364­5­54­80) Electrical installations of buildings. Part 5: Selectionand erection of electrical equipment. Chapter 54. Earthing arrangements and protective conductors

GOST R 50571.16­2007 (IEC 60364­6: 2006) Electrical installations of low voltage. Part 6: Tests

GOST R 51317.2.5­2000 (IEC 61000­2­5­95) compatibility of technical equipment. ElectromagneticEnvironment. Classification of electromagnetic interference at the locations of hardware

GOST R 51317.6.1­2006 (IEC 61000­6­1: 2005) Electromagnetic compatibility of technicalequipment. Immunity technical means used in residential and commercial and industrial environmentswith low power consumption. Requirements and test methods

GOST R 51317.6.2­2007 (IEC 61000­6­2: 2005) Electromagnetic compatibility of technicalequipment. Immunity of technical equipment used in industrial areas. Requirements and test methods

GOST R 51317.6.3­2009 (IEC 61000­6­3: 2006) Electromagnetic compatibility of technicalequipment. Electromagnetic interference on the technical means used in residential and commercialareas and industrial areas with low power consumption. Limits and test methods

GOST R 51317.6.4­2009 (IEC 61000­6­4: 2006) Electromagnetic compatibility of technicalequipment. Electromagnetic interference on the technical means used in industrial areas. Limits and testmethods

GOST R IEC 60950­1­2009 Information technology equipment. Safety requirements. Part 1: Generalrequirements

GOST 29322­92 (IEC 38­83) Standard voltages

441 (Free)

442 low­voltage electrical protection from temporary surgecaused by ground fault in the high voltage systems and injuries inlow­voltage

442.1 Scope

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This section contains the requirements for the safety of low­voltage electrical installations in thefollowing cases:

­ Earth fault in the high voltage transformer substation, installation of low­voltage supply (see para.442.2);

­ Break the neutral supply chain of low­voltage (cm. 442.1.3);

­ Accidental grounding line conductor in an IT system with low­voltage neutral conductor (see para.442.4);

­ Short­circuit between the line conductor and the neutral conductor in low voltage systems (see para.442.5), which usually leads to the most severe temporary overvoltage.

The requirements for the grounding devices of transformer substations are given in IEC 61936­1 [1].

442.1.1 General requirements

The requirements of section 442 shall be taken into account when designing and building substationsin the event of a ground fault on the high voltage distribution substations.

The design should have the following information relating to the high­voltage system:

­ Characteristics of the grounding system;

­ The maximum level of current ground fault;

­ The value of resistance grounding device.

442.1.2 Designations

In section 442, the following notation (see. Figure 44.A1):

­ Part of the earth current in the high voltage, which flows through the grounding devicesubstation;

­ Resistance grounding device substation;

­ Resistance grounding device exposed conductive parts of the installation of low­voltageequipment;

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­ Resistance neutral grounding device of low voltage electrically independent grounding devicesubstation and neutral system of low voltage;

­ TN systems and TT ­ nominal rms AC voltage line conductor with respect to ground, systemsIT ­ AC voltage between line conductor and neutral conductor or conductor medium, respectively;

­ Damage to the power frequency voltage that occurs in the low voltage between the exposedconductive parts and earth during a fault;

­ Critical power­frequency voltage between line conductor and the exposed conductive parts ofthe low voltage transformer substation during a fault;

­ Critical power­frequency voltage between line conductor and the exposed conductive parts ofthe low voltage installation of low voltage during the fault.

Note 1 ­ Critical power­frequency voltage (and) ­ a voltage that appears on the insulation oflow voltage equipment and overvoltage protection devices connected to low­voltage systems;

­ The fault current flowing in the grounding device exposed conductive parts of the equipment setat a low voltage during the period when there is damage on the high side and the first fault in theinstallation of low voltage (see. Table 44.A1);

­ The fault current in accordance with 411.6.2 flowing through the grounding device exposedconductive parts of the installation of low voltage during the first damage in the low voltage (see. Table44.A1);

­ Impedance (for example, the impedance of the insulation monitoring device (USP), theimpedance of the artificial neutral) between the low voltage and ground connection.

Note 2 ­ Earthing device can be considered electrically independent of the other grounding device, ifthe excess capacities relative to the ground on one of the grounding device does not cause unacceptableexcess capacities relative to ground on another grounding device (see. IEC 61936­1 [1]).

Figure 44.A1 ­ typical simplified scheme of the possible ways of earthing substation and the installation of low­voltageand overvoltage, occurring in the case of damage

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GOST R 50571­4­44­2011 (IEC 60364­4­44: 2007) Electrical installations of low voltage.Part 4­44. Safety requirements. Protection against voltage variations and electromagnetic

interference

Figure 44.A1 ­ typical simplified scheme of the possible ways of earthing substation and the installationof low­voltage and overvoltage, occurring in the case of damage

442.2 Overvoltage in low­voltage ground fault on the high voltage side

In the event of a ground fault on the high­voltage substation on the installation of low voltage mayaffect the following types of surge:

­ Fault voltage of industrial frequency ();

­ The critical frequency voltage (and).

Suitable methods for calculating various kinds of surges are shown in Table 44.A1.

Note 1 ­ Table 44.A1 apply to IT systems derived from the neutral point. For IT systems withoutderived neutral point should be selected corresponding to the formula listed in Table 44.A1.

Table 44.A1 ­ Critical power frequency voltage and power frequency voltage damage in low­voltageinstallations

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GOST R 50571­4­44­2011 (IEC 60364­4­44: 2007) Electrical installations of low voltage. Part 4­44. Safety requirements. Protection against voltage variations and electromagnetic interference

For the case where the grounding device of high and low voltage are located in close proximity toeach other, there are two ways of applying the operation:

­ Connect all the high () and low voltage () grounding devices to each other;

­ Separation of high () and low voltage () grounding devices from each other.

The main method is the mutual connection. If the system is a low voltage is fully located on theterritory of grounding devices of high voltage, grounding devices of high and low voltage must beconnected together (see. IEC 61936­1 [1]).

Note 2 ­ Features various types of earthing system (TN, TT, IT) are given in Standard 50571­1.

Note 3 ­ Requirements for and obtained on the basis of the criteria adopted in the design forthe isolation of low­voltage equipment, taking into account the temporary power frequency overvoltage(see. Also table 44.A2).

Note 4 ­ The system, which is connected to the neutral grounding device substation, such temporaryovervoltage may occur as the isolation that is not in a grounded shell, if the equipment is located outsidethe building.

Note 5 ­ systems TT and TN expression "coupled" and "Section" refer to the electrical connectionbetween and. For an IT system, these terms refer to the electrical connection between and and between

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the compound and.

442.2.1 The value and duration of the power frequency voltage in case of damage

The voltage at damage specified in the table 44.A1 that occurs in the installation of low voltage

between the exposed conductive parts and earth must not exceed the values for the correspondingduration of the damage, the curve shown in the figure 44.A2.

Figure 44.A2 ­ allowable stress damage in the low­voltage ground fault in the high voltage

GOST R 50571­4­44­2011 (IEC 60364­4­44: 2007) Electrical installations of lowvoltage. Part 4­44. Safety requirements. Protection against voltage variations and

electromagnetic interference

Figure 44.A2 ­ allowable stress damage in the low­voltage ground fault in the high voltage

Typically PEN­conductor is a low voltage system is connected to the earth at more than one point. In

this case, the overall resistance decreases. For such multiple­PEN grounded conductors may bedefined as:

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.

Note ­ The curve shown in Figure 44.A2 ­ IEC 61936­1 [1]. On the basis of probability and statistics,this curve shows a low level of risk for a simple worst case, when the neutral conductor is grounded onlyon the grounding device substation. Explanations for other situations are given in IEC 61936­1 [1].

442.2.2 The value and duration of the critical power frequency

The value and duration of the critical frequency voltage (and) low­voltage equipment in theinstallation of low­voltage ground fault in the high voltage, calculated in accordance with the table 44.A1should not exceed the values shown in Table 44.A2.

Table 44.A2 ­ Possible critical frequency voltage

The duration of an earth fault in the high voltagesystems, t

Permissible critical power frequency voltage on theequipment in low­voltage installations

> 5c In 250

<5c In 1200

In systems without neutral conductor value should be equal to the line voltage

Note 1 ­ The first line of the table refers to a system with a lot of time off, such as high­voltagesystems with isolated neutral or high voltage systems, grounded through the resonance resistance.

The second line refers to a high­voltage system with a short trip, for example to systems of highvoltage through a grounded low impedance. Together both of these lines are the design criterion forthe insulation of low­voltage equipment for temporary power frequency overvoltage (see. IEC 60664­1[2]).

Note 2 ­ The system, which is connected to the neutral earthing system of the transformersubstation, the emergence of such temporary surge is also possible on the isolation that is not in shellgrounded for equipment located outside of buildings.

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442.2.3 Requirements for the calculation of limit values

Permissible critical frequency voltage should not exceed the values shown in Table 44.A2.

Permissible fault voltage power frequency shall not exceed the value shown in Figure 44.A2.

For systems powered by electricity distribution network of low voltage requirements of 442.2.1 and442.2.2 run.

To fulfill the above requirements should be coordinated between the operator of the high voltage andlow voltage systems developer. Ensuring compliance with these requirements is the responsibility of thebuilder (owner operator) substation, which should also ensure compliance with the requirements of IEC

61936­1 [1]. Therefore, the calculation, and for the developer system voltage low, usually notrequired.

Possible measures for the implementation of the above requirements are, for example:

­ The separation of grounding devices of high voltage and low voltage;

­ Change the type of earthing system of low voltage;

­ Reduction of earth resistance.

442.3 The critical voltage of industrial frequency in the event of loss of neutralconductor in TN and TT systems

Please note that in case of breakage of the neutral conductor in a multiphase system, the basic, doubleand reinforced insulation and components designed for the voltage between line and neutral conductors

may be temporarily exposed to the line voltage, which can reach values.

442.4 The critical voltage of industrial frequency in the event of an earth fault in anIT system with neutral conductor

Please note that in case of accidental earth fault of neutral conductor IT system insulationcomponents designed for the voltage between the linear and neutral conductors may be temporarily

exposed to the line voltage, which can reach values.

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442.5 The critical voltage of industrial frequency in the event of a short circuitbetween the line conductor and the neutral conductor

Note that in the event of a short circuit in the installation of low voltage between line conductor andneutral conductor voltage between the other line conductors and the neutral conductor can reach a value

of 1.45 for up to 5 seconds.

443 protection from atmospheric or switching overvoltage

443.1 General requirements

This section establishes the requirements for the protection of electrical equipment from transientovervoltage of atmospheric origin transmitted by the supply of electric power distribution system, and byswitching surges.

Values switching surges are lower than arresters, so compliance with the requirements for protectionagainst overvoltage of atmospheric origin also provide protection against switching overvoltage.

Note 1 ­ The statistical evaluation of the measurements show that the risk of exceeding the switchingovervoltage surge level of Category II is small (see para. 443.2).

Values surges that may occur at the input to the electrical system, the expected number ofthunderstorm days a year, accommodation and features surge protection devices must be considered sothat the probability of accidents due to the surge has been lowered to a level acceptable for the safety ofpeople and material values as well as to provide the desired continuity of the service.

Values Transient surge depends on the method of implementation of the feed distribution system(line laid in the ground. Or overhead line), from the possible presence of surge protection devicesupstream input to the electrical system in the course of distribution of electricity, and the level of thesupply voltage.

This section provides guidance to determine in which cases the overvoltage protection is provided bysurge protection measures provided in the installation, and public should be provided with externalprotection devices.

If the protection in accordance with this section is not provided, it means that the coordination of theinsulation is not guaranteed and should be evaluated damage that may be caused by overexertion.

This section does not apply to surge arising from a direct lightning strike and lightning strikesoccurring in the vicinity of the installation. To protect against overvoltage transients generated by a directlightning strike, it is necessary to use IEC 62305­1 [3] IEC 62305­3 [4] and IEC 62305­4 [5], as well as

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the IEC 61643 series of standards [6].

This section does not apply to surge, resulting in data transmission systems.

Note 2 ­ In respect of transient overvoltage of atmospheric origin differences for grounded andungrounded systems available.

Note 3 ­ Switching overvoltages generated outside the unit and transmitted over a power line, areunder consideration.

Note 4 ­ The risk of damage from surges in IEC 62305­2 is considered [7].

443.2 Classification of equipment resistance to surge voltage (over­voltageclassification categories)

443.2.1 Appointment resistance classification equipment to the surge voltage (over­voltage categoryclassification)

Note 1 ­ For the purpose of insulation coordination in electrical overvoltage category are determinedand presented to the appropriate classification of resistance of electrical equipment to the surge voltage(see. Table 44).

Note 2 ­ The nominal resistance of the equipment to the surge voltage ­ it withstand impulse voltageequipment, the manufacturer of the equipment or part thereof and is characterized by the ability of itsspecified insulation withstand surge (in accordance with IEC 60664­1 [2], para 3.9.2).

Resistance of equipment to the surge voltage (overvoltage category) is used to classify the equipmentis powered directly from the mains.

The values of resistance to the surge voltage equipment selected for the rated voltage are given todetermine the different levels of fitness equipment on the life expectancy and acceptable risk of damage.The choice of equipment classified resistance to pulse voltage across the electrical installation can beensured coordination of insulation, lowering the risk of damage to an acceptable level.

Note 3 ­ The majority of electrical overvoltage transients transmitted supply system downstream ofthe power distribution are attenuated slightly.

443.2.2 The relationship between the resistance of equipment to the surge voltage and overvoltagecategory

Equipment with resistance to pulse voltage corresponding to overvoltage category IV is suitable foruse in commissioning the installation, or near it, for example, above the main switchboard. Equipment

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category IV has a very high resistance to surge voltage, providing the required high level of reliability.

NOTE 1 ­ Examples of such equipment include electrical measuring instruments, devices, primaryovercurrent protection devices and ripple smoothing.

Equipment with resistance to pulse voltage corresponding to overvoltage category III, suitable for usein fixed installations downstream distribution of electricity, including the main switchboard, and providesa high level of operational efficiency.

NOTE 2 ­ Examples of such equipment are distribution boards, circuit breakers, wiring, includingcables, busbars, junction boxes, switches, socket­outlets in the fixed installations, equipment for use inindustrial environments and some other equipment, such as fixed­mounted engine with a permanentconnection fixed installations.

Equipment with resistance to pulse voltage corresponding to overvoltage category II is suitable forconnection to fixed installations and provide a normal level of compliance with the requirementsgenerally to power consumers.

Note 3 ­ Examples of such equipment are household appliances and similar loads.

Equipment with resistance to pulse voltage corresponding to overvoltage category I is suitable for usein fixed electrical installations of buildings when to limit overvoltage transients to a predetermined levelapplied remedies set out equipment.

Note 4 ­ Examples of such equipment is equipment containing electronic circuit, such as computers,appliances with electronic programming, etc.

Equipment with resistance to pulse voltage corresponding to overvoltage category I should not beconnected directly to the electricity distribution network.

443.3 Performing surge protection

Overvoltage protection to be performed in accordance with the following requirements.

443.3.1 Surge protection in the installation

This paragraph shall not apply if there must be a risk assessment carried out in accordance with443.3.2.2.

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If the unit is powered by a low voltage, fully laid in the ground, and has no overhead lines, the valuesof resistance equipment Surge corresponding table 44, are sufficient, and special protection againstovervoltage of atmospheric origin is not required.

Note 1 ­ The cable with insulated conductors and the grounded shell, hung on the supports,considered equivalent to cable laid in the ground.

If the unit is powered by a low voltage overhead line and includes the air line and the number ofthunderstorm days per year less than or equal to 25 (AQ1 in accordance with IEC 60364­5­51 [8]),special protection against overvoltage of atmospheric origin is not required.

Note 2 ­ Regardless of the AQ (in accordance with IEC 60364­5­51 [8]), overvoltage protectionequipment may be necessary, if you want higher reliability and expected higher risks (eg fire).

In both cases, attention should be paid to protection against overvoltage transients equipment withresistance to pulse voltage corresponding to overvoltage category I (see para. 443.2.2).

443.3.2 Overvoltage protection with external devices

In all cases, attention should be paid to protection against overvoltage transients equipment withresistance to pulse voltage corresponding to overvoltage category I (see para. 443.2.2).

443.3.2.1 Overvoltage protection depending on external factors

If the electrical installation is fed by an air line or includes the air line and the number ofthunderstorm days per year is more than 25 (AQ2 according to IEC 60364­5­51 [8]), protection againstovervoltage of atmospheric origin is required, without the need to protective level of protective deviceswas higher than the level of overvoltage category II, given in Table 44 B.

Note 1 ­ The level of surge can be controlled by surge protection devices installed near the input inelectrical or air lines (see. Annex B), or in the installation of the building.

Note 2 ­ In accordance with IEC 62305­3, paragraph A.1 [4], the number of storm days per year,

equal to 25, equivalent to 2.5 lightning strikes per 1 km per year. It is derived from the formula

.

where ­ frequency of lightning strikes per 1 km per year;

­ The number of thunderstorm days per year.

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443.3.2.2 Overvoltage protection depending on the risk assessment

Note 1 ­ The method of overall risk assessment is given in IEC 62305­2. [7] In section 443 accepted

a substantial simplification of the method. It is based on the critical length of the incoming lines andthe level of the effects listed below.

For different levels of protection covers the following consequences:

a) relating to human life, such as security systems, medical equipment in hospitals;

b) concerning the provision of public services, such as disturbances in utility networks, informationtechnology centers, museums;

c) relates to the commercial and industrial activities, such as hotels, banks, industrial enterprises,commercial markets, agricultural enterprises;

d) relating to groups of individuals, such as large residential buildings, churches, offices, schools;

e) relating to individuals, such as apartment buildings, small offices.

To level the consequences set out in a) to c), overvoltage protection is needed.

Note 2 ­ No need for an estimate of the risk to the effects of the levels specified in a) to c), as resultof this calculation is always a need to implement protection.

To level the consequences referred to in items d) and e), the requirement to implement overvoltageprotection depends on the results of calculation. The calculation must be performed using the formulaspecified in Annex C to determine the length, which was adopted by agreement, and is called theconditional length.

Surge protection is required if,

where ­ conditional length in km power line reporting structure with a maximum value of 1 km;

­ The critical length;

Km is ­ the consequences for the level specified in item d), and is ­ the consequencesfor the level specified in item f)

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where ­ frequency of lightning strikes per 1 km per year.

If the calculation shows that the installation of surge protection devices is required, then the securitylevel of these devices should be higher than the level of overvoltage category II, given in Table 44 B.

443.4 required resistance to the surge voltage equipment

The equipment should be selected so that the nominal resistance to pulse voltage was not less thanthe required resistance to surge voltage shown in Table 44 B.

Table 44 ­ Required resistance to the surge voltage equipment

Rated voltage installations, in

The required resistance to impulse voltage kV

The three­phasesystem

Single­phase

system to amidpoint

Equipment forentering intothe unit (IVcategoryperena­ voltage)

Equipmentdistribution andfinal circuits (IIIovervoltagecategory)

Electricalappliances andpower consumers(II overvoltagecategory)

Speciallyprotected

equipment (Iovervoltagecategory)

­ 120­240 4 2.5 15 0.8

230/400 277/480 ­ 6 4 2.5 15

400/690 ­ 8 6 4 2.5

1000 ­ 12 8 6 4

­ In accordance with IEC 60038 [9].

­ Impulse withstand voltage between line conductors and PE.

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444 Protection against electromagnetic influences

444.1 General requirements

This section contains the basic recommendations for the suppression of electromagnetic interference.Electromagnetic interference can disrupt or damage the information technology system, informationtechnology equipment, as well as equipment with electronic components or circuits. The currents causedby lightning discharges, switching operations, short circuits, and other electromagnetic phenomena maylead to a surge and electromagnetic interference.

These impacts are most severe:

­ If the closed metal loops and a large area

­ The laying of the common routes of various electrical wiring in a building, for example, for powersupply and for the transmission of data signals intended for information technology equipment.

The value of the induced voltage is dependent on the steepness of the rise of the currentinterference and the size of the circuit. Power cables, through which flows a large current with highsteepness of current rise GOST

R(eg, motor starting currents elevators or currents adjustable semiconductor

rectifiers) may direct cables information technology systems surge that may affect the informationtechnology equipment and similar equipment, or damage him.

The premises of medical devices and near their electric or magnetic fields associated with electricalinstallations can interfere with medical equipment.

This section contains information for professionals in the construction of buildings and for specialistsin the design and installation of electrical installations of buildings, regarding certain decisions that limitelectromagnetic effects. The focus is on impacts that can cause interference.

444.2 (free)

444.3 Definitions

Basic terms and definitions given in GOST R 50571.1. This standard uses the following terms anddefinitions:

444.3.1 system of potential equalization (bonding network BN): The set of interconnected conductivestructures that provides "electromagnetic shield" for electronic systems at frequencies from dc to low rf.

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Note ­ The term "electromagnetic screen" means any structure used to divert another channel,blocking or hampering the passage of electromagnetic energy. In general, the potential equalizationsystem requires no connection to the land, but the system of equalization of potentials considered in thisstandard is connected to the ground.

444.3.2 annular conductor potential equalization (bonding ring conductor BRC): Earth bar, designedas a closed ring.

Note ­ Normally, the annular conductor potential equalization as part of potential equalization hasmultiple connections with the general system of equalization of potentials to improve its effectiveness.

444.3.3 combined potential equalization system (common equipotential bonding system CBN):potential equalization system, which provides a protective equalizing potentials and functional potentialequalization.

444.3.4 potential equalization (equipotential bonding): The electrical connection of conductive parts inorder to achieve equipotential.

444.3.5 network of earth electrodes (earth electrode network): Part of the grounding device, consistingof interconnected grounding electrodes.

444.3.6 system equipotential mesh type (meshed bonding network MESH­BN): The system ofequalization of potentials in which all the relevant support structures, racks, cabinets, as well as the returnwire DC power line connected and with a combined system of equalization of potentials in set points andmay form a mesh shape.

Note ­ The system equalization of potentials in a grid system enhances the efficiency of the combinedpotential equalization.

444.3.7 shunt conductor potential equalization / parallel earth conductor (by­pass equipotentialbonding conductor / parallel eaarthing conductor PEC): The grounding conductor connected in parallelshielded cable, transmitting signals and / or information to limit the current flowing through the screens.

444.4 EMI suppression

When designing and installing the electrical system should be used in this section referred to measurereduction of electric and electromagnetic effects on the electrical equipment.

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Use only such electrical equipment which complies with the relevant standards for electromagneticcompatibility (EMC) and the requirements of the relevant EMC product standards.

444.4.1 sources of electromagnetic interference

Electrical equipment that is sensitive to electromagnetic influences, should not be placed nearpotential sources of electromagnetic emissions such as:

­ Switching devices for inductive loads;

­ Electric motors;

­ Fluorescent lighting;

­ Welding machines;

­ Computers;

­ Rectifiers;

­ Breakers;

­ Frequency converters / regulators;

­ Lifts;

­ Transformers;

­ Complete switchgear;

­ Power distribution busbars.

Safety 444.4.2 reducing electromagnetic interference

The following measures reduce the effects of electromagnetic interference:

a) The application for electrical equipment sensitive to electromagnetic interference, surge protectiondevices and / or filters for improved electromagnetic compatibility with respect to conductedelectromagnetic phenomena;

b) joining metal sheaths of cables to the combined system of equalization of potentials;

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c) elimination of inductive circuits using common routes for laying of power, information and signalcircuits in wiring.

Note ­ Data cables ­ a cable for transmitting signals and data for the information technologyequipment and other sensitive to electromagnetic interference equipment;

d) separating power and signal cables and perform the intersection of each other, if possible almost atright angles (see. 444.6.3);

e) the use of cables with concentric conductors to reduce currents induced in the protective conductor;

f) The use of symmetric multi­core cables (eg shielded cables with separate protective conductor) forelectrical connections between the inverter and electric motors with variable frequency drives;

g) Application of signal and data cables that meet the requirements of the manufacturer toelectromagnetic compatibility;

h) in the presence of a lightning protection system

­ Power and signal cables must be separated from the electrodes of the lightning protection system, orthe minimum distance or through screening. The minimum distance should be determined by the designof the lightning protection system in accordance with IEC 62305­3 [4];

­ Metal sheaths and armor of power and signal cables must be connected to the equipotential bondingsystem in accordance with the requirements of lightning protection given in IEC 62305­3 [4] and IEC62305­4 [5];

i) if using shielded signal and data cables for the transmission of signals and information measuresshould be taken to limit the flow of fault currents on power systems earthed screens and veins signal ordata cables. In this case, you may need to pad the additional conductors such as shunt conductor potentialequalization to increase cable screen (see. Figure 44.R1).

Figure 44.R1 ­ shunt conductor to increase the screen in a combined system of equalization of potentials

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Figure 44.R1 ­ shunt conductor to increase the screen in a combined system of equalization of potentials

Note 1 ­ Installation of the conductor near the shell of the signal or data cable reduces the area of thecircuit associated with the equipment attached to the ground only to the protective conductor. Thismeasure significantly reduces the level of pulsed electromagnetic influences by lightning discharges;

j) If the signal or data cables are common to several buildings, powered by the CT system should beapplied to the bypass conductor potential equalization (see. Figure 44.R2). Minimum cross­section of the

copper conductor shunt should be 16 mm or the equivalent conductivity of other metals. The equivalentconductivity cross­sectional area must be determined in accordance with IEC 60364­5­54 (paragraph544.1) [10].

Figure 44.R2 ­ examples of replacement or bypass conductor potential equalization system TT

Figure 44.R2 ­ examples of replacement or bypass conductor potential equalization system TT

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Note 2 ­ If a grounded shield conductor is used as the reverse current signal circuit may be used dualcoaxial cable.

Note 3 ­ If no agreement on how to connect the screens of telecommunications cables to the mainpotential equalization system can not be achieved, the responsibility for avoiding a risk that may arisedue to such cables unconnected to the main potential equalization system rests with the owner oroperator.

Note 4 ­ The correction of problems caused by the voltage difference on the ground in the extendedmunicipal telecommunication networks, is assigned to the telecommunications network operators, whichcan use other ways;

k) impedance connections to the equipotential bonding system should be as small as possible, which isprovided as follows:

­ As short as possible due to the length of the connection and / or cross­sectional shape of theconductor, provides a low inductance values of resistance and impedance per meter of track (forexample, woven braid with a width to thickness ratio of five to one);

l) if the earthing bar is designed to perform the functions of the equipotential bonding apparatuscomprising a significant amount of information technology equipment in the building, it may be formedas a closed ring.

Note 6 ­ This measure should be preferred in the buildings of the telecom industry.

444.4.3 TN system

To reduce electromagnetic interference must meet the requirements of the following items:

444.4.3.1 In existing buildings, which contain or may contain a significant amount of informationtechnology equipment, it is not recommended to keep the system TN­C.

In the newly constructed buildings, which contain or may contain a significant amount of informationtechnology equipment, should not be used system TN­C.

Note ­ In any installation of TN­C is likely course of load currents or fault currents, branchingthrough the potential equalization at the metal structure of the building and communications.

444.4.3.2. In existing buildings, powered by electricity distribution networks of low voltage, whichcontain or may contain a significant amount of information technology equipment should be installedTN­S, from entering into the electrical system (see. Figure 44.R3A).

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In the newly constructed buildings, which contain or may contain a significant amount of informationtechnology equipment should be installed TN­S, from entering into the unit (see. Figure 44.R3A).

Figure 44.R3A ­ Exception neutral conductor currents in design, connected to the equipotential bonding system, usingthe system TN­CS division PEN­conductor to the protective conductor PE and neutral conductor N on the input powerelec

_______________

In normal operation the voltage drop in the PE conductor is absent.

The contours of a limited area caused by signal or data cables for the transmission of signals orinformation.

Figure 44.R3A ­ Exception neutral conductor currents in design, connected to the equipotential bonding

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system, using the system TN­CS division PEN­conductor to the protective conductor PE and neutralconductor N on the power input of the electrical system in the municipal network

Note ­ The effectiveness of the system TN­S can be enhanced using differential current monitoringdevices (RCM) in accordance with IEC 62020 [11].

444.4.3.3 In existing buildings, where the installation of low voltage completely, including transformer,served only by the consumer and that contain or may contain a significant amount of informationtechnology equipment should be installed TN­S (see. Figure 44.R3V).

Figure 44.R3V ­ Exception neutral conductor currents in design, connected to the equipotential bonding system, using asystem of TN­S electrical installations in buildings, powered by its own transformer consumer

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_______________

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In normal operation the voltage drop in the PE conductor is absent.

The contours of a limited area caused by signal or data cables for the transmission of signals orinformation.

Figure 44.R3V ­ Exception neutral conductor currents in design, connected to the equipotential bondingsystem, using a system of TN­S electrical installations in buildings, powered by its own transformer

consumer

444.4.3.4 If the existing installation made system TN­C­S (see. Figure 44.R4), the contours formed bysignal and data cables for the transmission of signals or information that can be eliminated:

­ Replacing all electrical parts, executed by system TN­C shown in Figure 44.R4, system TN­S, asshown 44.R3A, or

­ If such a replacement is impossible, except for compounds of various parts of the system TN­Ssignal or data cables for the transmission of signals or information.

Figure 44.R4 ­ System TN­C­S division PEN­conductor to the protective conductor PE and neutral conductor N into anexisting electrical installation of the building

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_______________

The voltage drop in the PE conductor in the normal mode.

The contours of a limited area caused by signal or data cables for the transmission of signals orinformation.

Extraneous conductive parts.

Note ­ The current system, which in TN­S takes place only at the neutral conductor in the TN­C­Salso takes place on the screen or reference conductors of the signal cables, * an open conductive partsand extraneous conductive parts, such as steel structures. _______________

* Probably the original error. It should read: open. ­ Note manufacturer's database.

Figure 44.R4 ­ System TN­C­S division PEN­conductor to the protective conductor PE and neutralconductor N into an existing electrical installation of the building

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444.4.4 TT system

The CT system such as that shown in Figure 44.R5, must be considered overvoltages which mayexist between the conductive parts and conductive parts exposed in those cases where the exposedconductive parts of different buildings are connected to different earth connections.

Figure 44.R5 ­ the CT system in the electrical installation of the building

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_______________

The voltage drop in the PE conductor in the normal mode.

The contours of a limited area caused by signal or data cables for the transmission of signals orinformation.

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Figure 44.R5 ­ the CT system in the electrical installation of the building

444.4.5 IT system

The three­phase IT (see. Figure 44.R6) should take into account that the single fault isolationbetween the line conductor and the exposed conductive part of the voltage between the intact linearconductor and an exposed conductive part can reach the level of the line voltage.

Note ­ Electronic equipment, food which provides a direct connection between the linear conductorand the neutral conductor must withstand such over­voltage between line conductor and the exposedconductive parts (see. The requirement to GOST R IEC 60950­1 for equipment of informationtechnology).

Figure 44.R6 ­ IT system in the electrical installation of the building

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_______________

The voltage drop in the PE conductor in the normal mode.

The contours of a limited area caused by signal or data cables for the transmission of signals orinformation.

Figure 44.R6 ­ IT system in the electrical installation of the building

444.4.6 Power from multiple sources

When powered by multiple sources should apply measures specified in 444.4.6.1 and 444.4.6.2.

Note ­ When using multiple grounding points neutral power source currents in the neutral conductorcan flow in the opposite direction to the corresponding neutral point not only in the neutral conductor butalso on the protective conductor, as shown 44.R7A. For this reason the sum of the partial currentsflowing in the installation, will not be zero, and therefore the parasitic electromagnetic field is createdsimilar to the created solid cable.

Figure 44.R7A ­ TN­S system with multiple power sources and unacceptable multiple connections between PEN­conductor and earth

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and electromagnetic interference

Figure 44.R7A ­ TN­S system with multiple power sources and unacceptable multiple connectionsbetween PEN­conductor and earth

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In the case of single­core cables in which an alternating current around the conductor cable conductorformed circular electromagnetic field, which can affect the electronic equipment. Similar fields arecreated as harmonic currents, but these fields are attenuated faster than those created by major currents.

444.4.6.1 Powered by multiple sources in TN

In the case of electrical power in the system from several sources TN neutral point sources ofelectromagnetic compatibility considerations must be interconnected insulated conductor connected toground in common to the audio source point located in the center between the sources (see. Figure44.R7B) .

Figure 44.R7V ­ System TN­S c multiple sources of power with the addition of neutral point to earth in the same point

_______________

Avoid direct connection to the earth no neutral point of transformer or generator.

The conductor connecting the neutral points of transformers and generators of all, must be isolated.This conductor is the PEN­conductor and be well marked, but it should not accede to power consumers,about what must be done warning sign attached to it or installed next to it.

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It should be performed only one connection between the interconnected neutral point of the supplyand the PE conductor. This connection must be inside the main switchboard.

Can be made extra grounding of the PE conductor in the installation.

Figure 44.R7V ­ System TN­S c multiple sources of power with the addition of neutral point to earth inthe same point

444.4.6.2 Power from several sources in the CTs

In the case of electrical power supply from multiple sources in the CT system EMC reasons it isrecommended that the neutral points of all sources are interconnected and connected to ground at onlyone point located at the center between the sources (see. Figure 44.R8)

Figure 44.R8 ­ TT system c multiple sources of power with the addition of neutral point to earth in the same point

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Avoid direct connection to the earth no neutral point of transformer or generator.

The conductor connecting the neutral point of transformer or generator should be isolated. Thisconductor is a neutral conductor, and may be so designated, but it should not accede to power consumers,about what must be done warning sign attached to it or installed next to it.

It should be done only one connection between the interconnected neutral point of the supply andthe neutral conductor. This connection must be inside the main switchboard.

Figure 44.R8 ­ TT system c multiple sources of power with the addition of neutral point to earth in thesame point

444.4.7 Switching power supplies

In TN systems, switching power supply from one source to another source should be performed usinga switching device, the switching simultaneously linear conductors and the neutral conductor, if presentin the installation (see. Figures 44.R9A, 44.R9B, 44.R9C).

Figure 44.R9A ­ Switching to an alternate power source is a three­phase 4­pole switch

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Note ­ This switch prevents the occurrence of electromagnetic fields generated by stray currents in themain electrical power supply system. The amount of current in the same cable must be zero. This ensuresthat the flow of the current difference of linear conductors of the neutral conductor is only one circuit,which switches the electrical power supply.

Currents third harmonic (150 Hz) are added to the linear conductors of the neutral conductor currentwith the same phase angle.

Figure 44.R9A ­ Switching to an alternate power source is a three­phase 4­pole switch

Figure 44.R9V ­ The flow of currents in the neutral conductor when switching to an alternative power supply three­phase three­pole switch inappropriate

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Note ­ Switching to a backup power source in a three­phase network with a three­pole switchinappropriate results in the flow of unwanted circulating currents that create electromagnetic fields.

Figure 44.R9V ­ The flow of currents in the neutral conductor when switching to an alternative powersupply three­phase three­pole switch inappropriate

Figure 44.R9S ­ Switch to single­phase alternative power source 2­pole switch

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GOST R 50571­4­44­2011 (IEC 60364­4­44: 2007)Electrical installations of low voltage. Part 4­44. Safetyrequirements. Protection against voltage variations and

electromagnetic interference

Note ­ Connection to earth the secondary circuit unit uninterruptible power supply (UPS) is optional. Ifthis joining is not performed in the mode of power supply from the UPS, the power will be carried outaccording to the type of IT, and power mode with parallel power sources type of ground will beappropriate for the type of ground the main source.

Figure 44.R9S ­ Switch to single­phase alternative power source 2­pole switch

444.4.8 Communications, included in the building

Metal pipes (eg water supply pipes, gas and central heating), power and control cables shouldpreferably enter the building in the same place. Metal pipes and metal cable armor must be connected tothe main ground bus using conductors having a minimum impedance (see. Figure 44.R10).

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Note ­ The interconnection of communications is permitted only with the consent of the operator ofexternal networks.

Figure 44.R10 ­ Example of entry armored cables and metal pipes into the building in one place

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GZSH ­ the main earthing bar; ­ induced current

Note ­ It is preferred to enter into one place, since wherein the value of the potential differencebetween the different communications is close to zero 0 V.

Figure 44.R10 ­ Example of entry armored cables and metal pipes into the building in one place

For reasons of EMC closed cavities of the building, which houses part of the electrical installation,should be reserved exclusively for electrical and electronic equipment (for example, devices formonitoring, control, protection and connection devices) for which the service should be accessible.

444.4.9 Installation in separate buildings

If different buildings are separate potential equalization system for signaling and data can be usedfiber­optic cables that do not have metal parts or other non­wired system, such as high­frequencyisolation transformers in accordance with IEC 61558­2­1 [12] , IEC 61558­2­4 [13] IEC 61558­2­6 [14]

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IEC 61558­2­15 [15] and GOST R IEC 60950­1.

Notes

1 The problems caused by the voltage difference on the ground in the extended municipaltelecommunication networks, are assigned to the network operators, which can use other ways.

2 In the case of data transmission systems neprovodnyh shunt conductor pad is not necessary.

444.4.10 Installation inside buildings

If the existing buildings are electrical problems associated with electromagnetic effects, to improvethe situation can be applied the following measures (see. Figure 44.R11):

1) use of fiber optic connectors, without metal parts, connections or signaling information (see. 444.4.9);

2) the use of equipment of class II;

3) the use of two­winding transformers in accordance with IEC 61558­2­1 [12] IEC 61558­2­4 [13] IEC61558­2­6 [14] IEC 61558­2­15 [15]. Compound secondary winding should preferably be executed onthe type of system TN­S, but for special applications the system may be adopted IT.

Figure 44.R11 ­ Examples of protection against interference in the existing building

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Designations

­ The point of connection of the protective conductor and functional ground;

FE ­ functional earth conductor (if necessary), and joins used as directed by the operator;

SPD ­ surge protection device;

­ Symbol of the PE conductor;

­ Symbol of the neutral conductor;

­ The symbol of a linear conductor

Link Description of the measure Sub / standard

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1) Entering cables and metallic pipes to a building in a place 444.4.8

2) Common routing to the appropriate division and exclusionloops

444.4.2

3) Jumpers shortest length for potential equalization and agrounded conductor parallel cable

GOST R 51317.2.5 444.4.2

4) Shielded signal cables and / or wires with twisted pairs 444.4.12

5) Exclusion of TN­C below the input power 444.4.3

6) The use of transformers with separate windings 444.4.10

7) Local horizontal system of equalization of potentials 444.5.4

8) Application of Class II equipment 444.4.10

Figure 44.R11 ­ Examples of protection against interference in the existing building

444.4.11 Protective devices

To avoid false alarms at high transient currents should be selected with the appropriate protectivedevices functional characteristics, such as delayed or filters.

444.4.12 Signal cables

As the signal cables should be screened cables and / or wires with twisted pairs.

444.5 Grounding and potential equalization

444.5.1 Interconnection grounding electrodes

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For several buildings if the electronic equipment used in communications systems and informationexchange between the various buildings, the principle of the implementation of separate, unrelatedgrounding electrodes attached to the equipotential bonding system, may not be relevant for the followingreasons:

­ Between such separate grounding electrodes, there is a mutual influence, which can lead to anuncontrolled increase in voltage on the equipment;

­ Interconnected equipment can have different voltages with respect to ground;

­ There is a risk of electric shock, especially in the event of overvoltage of atmospheric origin.

Therefore, all PE conductor and functional ground must be connected to the same main earthing bus.Moreover, referring to the building grounding electrodes of different functions, such as protective,functional earthing and lightning protection ground should be connected together (see. Figure 44.R12).

Figure 44.R12 ­ Related grounding electrodes

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Figure 44.R12 ­ Related grounding electrodes

For several buildings if the interconnection of ground electrodes is practically impossible orimpractical, it is recommended to perform galvanic separation of communication networks of variousbuildings, such as through the use of fiber­optic inserts (see. 444.4.10).

The protective and functional bonding must be separately attached to the main earthing bus so as todetach any one of the conductor does not impair the reliability of connection of the remainingconductors.

444.5.2 Methods of connection of protective conductors and grounding devices

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The exposed conductive parts of information technology equipment and electronic equipment in abuilding must be interconnected by means of protective conductors.

For residential buildings, where electronic equipment is usually used to a limited extent, acceptableradial network of protective conductors (see. Figure 44.R13).

Figure 44.R13 ­ Examples of the radial connection of protective conductors

­ Grounding conductor;

­ Protective conductor

Figure 44.R13 ­ Examples of the radial connection of protective conductors

For public and industrial buildings with multiple more effective use of electronics is combinedpotential equalization system to ensure the requirements of the electromagnetic compatibility of differenttypes of equipment (see. Figure 44.R15).

444.5.3 Different wiring of conductors and potential equalization grounding conductors

Depending on the importance and sensitivity of the equipment may be used four main circuitscontained in the following paragraphs:

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444.5.3.1 Protective conductor connected to the ring conductor potential equalization

Potential equalization system using a ring conductor potential equalization is shown in Figure 44.R16on the top floor of the building. The annular conductor preferably be copper, bare or insulated, andshould be available at any location that can be achieved, for example, using a cable tray, metal pipes (see.The series IEC 61386 [16]) on the exposed surface of the gasket or conduit.

By the annular conductor potential equalization can be attached all protective conductors andfunctional earth.

444.5.3.2 Radial circuit connection of protective conductors

This scheme is applicable to small plants respective living quarters and a small commercial buildings,and in general ­ for equipment not having the interconnections made signal cables for the transmission ofinformation (see. Figure 44.R13).

444.5.3.3 The radial connection of several mesh systems

This connection is applicable for small installations with a small private group of relatedcommunication equipment and contributes to the local dispersion currents due to electromagneticinterference (see. Figure 44.R14).

Figure 44.R14 ­ Example of radial connecting several mesh systems

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­ Grounding conductor (protective or functional ground);

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­ Functional equipotential conductors.

The length of these conductors must be the shortest as possible (eg, <50 cm)

Figure 44.R14 ­ Example of radial connecting several mesh systems

444.5.3.4 Combined reticulate­radial system

This type of connection is used in systems with a high density of communication equipment and thespecial responsibility of the terms of its application (see. Figure 44.R15). Net potential equalizationsystem leverages existing hardware Buildings and supplemented conductors forming square cells.

Figure 44.R15 ­ Example of combined reticulate­radial system of equalization of potentials

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Figure 44.R15 ­ Example of combined reticulate­radial system of equalization of potentials

Dimensions of the grid should cover the entire area in which the equipment is located. The mesh sizeof the area expressed in square bounded conductors, forming a square.

The cell size is dependent on the level of a received lightning protection equipment of the level ofresistance to electromagnetic influences and from the frequencies used for information transmission. Thesize of the cells to be matched to the size of the protected installation, but not to exceed (2x2) m in theareas of installation, sensitive to electromagnetic interference.

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This scheme is suitable for local area networks (eg, PBX with incoming and outgoing calls) and forcentralized information processing systems. Where necessary, in the presence of specific requirements incertain areas a common grid cell sizes can be reduced.

444.5.4 Equipotential bonding in multi­storey buildings

In multi­storey buildings it is recommended to potential equalization system on each floor. The figureshows 44.R16 potential equalization system for the general case. Each floor is an example of one type ofpotential equalization. Potential Equalization various floors must be interconnected by at least twoconductors.

Figure 44.R16 ­ Example of a system of equalization of potentials in high­rise building without lightning

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Figure 44.R16 ­ Example of a system of equalization of potentials in high­rise building without lightning

444.5.5 functional ground conductor

For proper operation of some electronic equipment requires a reference voltage whose value is closeto the earth potential. This reference voltage is provided by a conductor functional ground.

Functional ground conductor may be metal strips, flat braided pigtails and cables with concentricarrangement of conductors.

For equipment operating at high frequencies, preferred are metal strips or flat braids, the length ofconnection which should be as short as possible.

For conductor functional ground is not a special color, but to refer to functional ground conductorsshould not be used a combination of the colors yellow and green set for the protective earthingconductor. Use of one and the same color to indicate the functional grounding conductors at each endwithin the whole plant.

For equipment operating at low frequencies, cross­section of conductors specified in IEC 60364­5­54, paragraph 544.1.1 [10] are sufficient regardless of the profile section of the conductor (see. Alsolisted b) and k) 444.4.2).

444.5.6 commercial or industrial building with a large volume of information technologyequipment

The following additional requirements are intended to reduce the effects of electromagneticinterference in the work of information technology equipment.

In conditions of strong electromagnetic influences it is recommended to use the combined reticulate­radial system of potential equalization in accordance with 444.5.3.3.

444.5.6.1 Dimensions and installation of conductors of the ring system of equalization of potentials

Ring bus provided by the project for potential equalization must have the following minimum cross­section:

­ Flat copper cross­section (30x2) mm;

­ Round copper, diameter of 8 mm.

Bare conductors must be protected against corrosion in places of attachment and pass through walls.

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444.5.6.2 parts to be attached to the system of equalization of potentials

For potential equalization system must be attached to the following parts:

­ Conducting screens, conductive sheath or armor of cables transmitting information data, and theshell of information technology equipment;

­ Grounding conductor antenna systems;

­ Grounding grounding conductor poles DC circuits supplying information technology equipment;

­ Guides functional ground.

444.5.7 Earthing and potential equalization for functional purposes of information technologysystems

444.5.7.1 Earth bar

If required for functional purposes grounding tire length of the main building electrical groundingclamp can be increased by the addition thereto a ground bus. This facilitates the connection ofinformation technology equipment to the main earthing terminal of the building at any point of thebuilding is almost the shortest route. If grounding rail mounted to improve the equipotential large amountof information equipment in the building, it may be formed as a ring (see. Figure 44.R16).

Notes

1 grounding rail can be bare or insulated.

Two grounding bus should be set so that access to it is provided over its entire length, for example on thesurface of the cable duct. At fixing and passageways through walls may require protection of conductorsagainst corrosion.

444.5.7.2 Efficiency bus functional ground depends on its track laying and the impedance of theconductor used. For installations connected to the supply chain with load capacity of 200 A per phase or

more cross sectional area of the bus functional ground must be at least 50 mm of copper, and the sizeand shape of the cross­section must comply with the requirements of listing k) 444.4.2.

Note ­ This requirement is valid for frequencies up to 10 MHz.

If the grounding bus is used as part of the return path of DC, its cross­section should be selected bythe calculated inverse DC. The maximum calculated DC voltage drop along each ground bus for use as areverse current conductor in the distribution chain, should be less than 1 V.

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444.6 Separation chains

444.6.1 General requirements

Laying of cables intended for information technology power supply cables in the same wiringsystem, or one track should be carried out in accordance with the requirements of this section.

Must meet the test for compliance with the electrical safety (see. GOST R 50571.16 and / or IEC60364­5­52, paragraph 528.1 [17], also requires electrical separation of circuits (see. GOST R 50571.3,section 413 and / or 444.7.2 ).

The requirements for separation distances under the terms of electrical safety and electromagneticcompatibility conditions may in some cases be different.

The exposed conductive parts of electrical wiring systems, such as shell, fasteners, partitions shouldbe protected in accordance with the requirements of the protection when insulation fault (see. GOST R50571.3, section 413).

444.6.2 Design information

The minimum distance between the cables for communication and power cables required to reducethe electromagnetic interference, depend on many factors, such as:

a) Level of resistance of the equipment connected to the data cable to the surge voltage andelectromagnetic influence of various kinds (current transients, pulse currents, current pulses of lightningflash, a circular wave, sustained oscillations, etc.);

b) connect equipment to the grounding device;

c) the nature of the local electromagnetic environment (the simultaneous occurrence of various types ofinterference, such as harmonics, plus flash, plus sustained oscillations);

d) range of the electromagnetic spectrum;

e) Distance between cables in parallel streams cables (zone of mutual influence);

f) The type of cables;

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g) the attenuation of the mutual influence of the cables;

h) The quality of contact connection between the cable and connector;

i) the nature and design of the electrical wiring system.

For the purposes of this standard it is assumed that the levels of electromagnetic interference in theenvironment do not exceed the test levels given in the GOST R 51317.6.1, GOST R 51317.6.2, GOST R51317.6.3 and GOST R 51317.6.4 for conducted and radiated noise.

With parallel cables for communication and power cables must meet the following conditions (see.Figures 44.R17A and 44.R17V).

Figure 44.R17A ­ Separation of power cables and cabling information technology in long cable runs less than or equalto 35 m

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­ power cable;

GOST ­ Data cable

Figure 44.R17A ­ Separation of power cables and cabling information technology in long cable runs of35 m

Figure 44.R17B ­ Separation of power and data cables during long cable runs> 35 m

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GOST ­ power cable;

GOST ­ Data cable;

­ Separation using distance or see the partition. Figure 44R18

Figure 44.R17B ­ Separation of power and data cables during long cable runs> 35 m

If the length of cables laid in parallel is equal to or less than 35 m, the separation is not required.

If the length of laying parallel with unshielded cables exceed 35 m separation distances between datacable to transfer data and power cables must be met for the entire length of the track, except for the final15 meters, attached to the terminals of the equipment.

Note ­ The separation can be achieved by air separation distance equal to 30 mm, or by a metal bafflemounted between the cables (see. Figure 44.R18).

Figure 44.R18 ­ Separation of cables in the wiring

Figure 44.R18 ­ Separation of cables in the wiring

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For shielded cables with a length of laying parallel with a 35 m separation is not required.

444.6.3 Installation instructions

The minimum distance between data cable to transfer information and fluorescent, neon, mercury (orother discharge lamps with high­intensity discharge) must be equal to 130 mm. Device for connectingdata cables and power cables have to be usually in different cabinets. Rack clamp for data cablestransmitting information and electric machinery must always be separated from each other.

Intersections cables should, where practicable, be carried out at a right angle. Cables of variouspurpose (such as power cables and transmission of information) should not be in the same bundle.Bunches of cables for different purposes should be separated from each other with regard toelectromagnetic interference (see. Figure 44.R18).

444.7 Systems wirings

444.7.1 General requirements

Systems for wirings are in metal and nonmetal performance. Hardware system for wirings providevarying degrees of enhanced protection under the terms of electromagnetic compatibility, provided thatthey are installed in accordance with 444.7.3.

444.7.2 Design information

The choice of material and shape of wirings depends on the following conditions:

a) the impact of the electromagnetic field strength along the route (the proximity of sources ofelectromagnetic interference conducted and radiated);

b) the allowable levels of conducted and radiated emissions;

c) the type of laid cables (shielded, twisted, fiber optic);

d) level of immunity to electromagnetic influences of equipment connected to the cable system, thetransmission of information;

Table of contents

Introduction440.1 Scope440.2 Normative references

441 (Free)442 low­voltage electrical protection from temporary surge caused by groundfault in the high voltage systems and injuries in low­voltage

442.1 Scope442.1.1 General requirements442.1.2 Designations

Figure 44.A1 ­ typical simplified scheme of the possibleways of earthing substation and the installation of low­voltage and overvoltage, occurring in the case of damage

442.2 Overvoltage in low­voltage ground fault on the high voltage side442.2.1 The value and duration of the power frequency voltagein case of damage

Figure 44.A2 ­ allowable stress damage in the low­voltageground fault in the high voltage

442.2.2 The value and duration of the critical power frequency

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e) other restrictive environmental conditions (chemical, mechanical, environmental, fire and others.);

f) any subsequent extension of the information cable network.

Non­metallic electrical wiring systems are suitable for applications:

­ Electromagnetic environments with consistently low levels of disturbances;

­ Cable system with low emissions;

­ The use of fiber optic cables.

In the case of metal components of the support system for the characteristic impedance of the cablewiring system is largely dependent on the profile construction (plane, U­shaped design, the tube and al.),Than from the cross­sectional area thereof. The best profiles are closed because they reduce the effects ofcommon mode.

Used space inside the cable tray should permit subsequent additional lining a predetermined numberof cables. The height of the cable bundle should be lower side of the tray as shown in Figure 44.R19. Theproperties of the tray in terms of electromagnetic compatibility improved by applying caps installedoverlapped.

Figure 44.R19 ­ Laying cables in metal cable trays

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Figure 44.R19 ­ Laying cables in metal cable trays

For trays U­shaped greatest attenuation of the magnetic field occurs at two corners of the tray, so it ispreferable to use deep tray (see. Figure 44.R19).

Note ­ The depth of the tray should be at least twice the size of the largest diameter of the cables laid.

444.7.3 Installation instructions

442.2.3 Requirements for the calculation of limit values442.3 The critical voltage of industrial frequency in the event of loss ofneutral conductor in TN and TT systems442.4 The critical voltage of industrial frequency in the event of anearth fault in an IT system with neutral conductor442.5 The critical voltage of industrial frequency in the event of a shortcircuit between the line conductor and the neutral conductor

443 protection from atmospheric or switching overvoltage443.1 General requirements443.2 Classification of equipment resistance to surge voltage (over­voltage classification categories)

443.2.1 Appointment resistance classification equipment to thesurge voltage (over­voltage category classification)443.2.2 The relationship between the resistance of equipment tothe surge voltage and overvoltage category

443.3 Performing surge protection443.3.1 Surge protection in the installation443.3.2 Overvoltage protection with external devices443.4 required resistance to the surge voltage equipment

444 Protection against electromagnetic influences444.1 General requirements444.2 (free)444.3 Definitions444.4 EMI suppression

444.4.1 sources of electromagnetic interferenceSafety 444.4.2 reducing electromagnetic interference

Figure 44.R1 ­ shunt conductor to increase the screen in acombined system of equalization of potentialsFigure 44.R2 ­ examples of replacement or bypassconductor potential equalization system TT

444.4.3 TN systemFigure 44.R3A ­ Exception neutral conductor currents indesign, connected to the equipotential bonding system,using the system TN­CS division PEN­conductor to theprotective conductor PE and neutral conductor N on theinput power elecFigure 44.R3V ­ Exception neutral conductor currents indesign, connected to the equipotential bonding system,using a system of TN­S electrical installations inbuildings, powered by its own transformer consumerFigure 44.R4 ­ System TN­C­S division PEN­conductor tothe protective conductor PE and neutral conductor N intoan existing electrical installation of the building

444.4.4 TT systemFigure 44.R5 ­ the CT system in the electrical installationof the building

444.4.5 IT systemFigure 44.R6 ­ IT system in the electrical installation ofthe building

444.4.6 Power from multiple sources

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444.7.3.1 metal or composite wirings system designed specifically for the purpose of electromagneticcompatibility

Metal or composite wirings system designed specifically for the purpose of electromagneticcompatibility must always be connected to the local equipotential bonding system at both ends. For largelengths, such as 50 m, it is recommended to perform an additional connection to the system ofequalization of potentials. All conductors connections must be of the shortest possible length. If thewiring system is composed of several elements must be taken to ensure the continuity of the circuit usingsecure connections adjacent elements. Preferably, the elements have to be welded together completelyaround the perimeter. Application rivet, bolt, screw connections are allowed if the contact surfaces aregood conductors, that is, no painting and insulation coatings are protected from corrosion and ensure areliable electrical contact.

Metal profile sections must be maintained over the entire length. All connections must have a lowimpedance. Compound sections wiring system using a short single wire will cause local high impedanceand deterioration of the properties of the system due to EMC (see. Figure 44.R20).

Figure 44.R20 ­ continuous system consisting of metal components

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Figure 44.R20 ­ continuous system consisting of metal components

At frequencies of several MHz and above mesh bar length of 10 cm between two parts of the systemreduces the electrical shielding effect of more than 10 times.

When making changes or extensions is very important that the work was done under close

Figure 44.R7A ­ TN­S system with multiple powersources and unacceptable multiple connections betweenPEN­conductor and earthFigure 44.R7V ­ System TN­S c multiple sources of powerwith the addition of neutral point to earth in the same pointFigure 44.R8 ­ TT system c multiple sources of powerwith the addition of neutral point to earth in the same point

444.4.7 Switching power suppliesFigure 44.R9A ­ Switching to an alternate power source isa three­phase 4­pole switchFigure 44.R9V ­ The flow of currents in the neutralconductor when switching to an alternative power supplythree­phase three­pole switch inappropriateFigure 44.R9S ­ Switch to single­phase alternative powersource 2­pole switch

444.4.8 Communications, included in the buildingFigure 44.R10 ­ Example of entry armored cables andmetal pipes into the building in one place

444.4.9 Installation in separate buildings444.4.10 Installation inside buildings

Figure 44.R11 ­ Examples of protection againstinterference in the existing building

444.4.11 Protective devices444.4.12 Signal cables

444.5 Grounding and potential equalization444.5.1 Interconnection grounding electrodes

Figure 44.R12 ­ Related grounding electrodes444.5.2 Methods of connection of protective conductors andgrounding devices

Figure 44.R13 ­ Examples of the radial connection ofprotective conductors

444.5.3 Different wiring of conductors and potential equalizationgrounding conductors

Figure 44.R14 ­ Example of radial connecting severalmesh systemsFigure 44.R15 ­ Example of combined reticulate­radialsystem of equalization of potentials

444.5.4 Equipotential bonding in multi­storey buildingsFigure 44.R16 ­ Example of a system of equalization ofpotentials in high­rise building without lightning

444.5.5 functional ground conductor444.5.6 commercial or industrial building with a large volume ofinformation technology equipment444.5.7 Earthing and potential equalization for functionalpurposes of information technology systems

444.6 Separation chains444.6.1 General requirements444.6.2 Design information

Figure 44.R17A ­ Separation of power cables and cablinginformation technology in long cable runs less than or

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supervision to guarantee compliance with its recommendations for EMC, for example, to the metalsection of pipe was replaced with plastic.

Metal structural elements of buildings can successfully serve the purpose of electromagneticcompatibility. Steel beams L­, H­, U­, T­profile often are continuous with the grounded structure potentcross­section, with a large surface area with multiple intermediates to ground. Laying cables in suchbeams is preferred. Preferably, the gasket inside corners and not on the outer surface (see. Figure 44R21).

Figure 44.R21 ­ Location of cables inside the elements of metal structures

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Figure 44.R21 ­ Location of cables inside the elements of metal structures

Caps, metal trays must meet the same requirements as the trays. Preferred cover with a large numberof fasteners to section. If not, the cover should be attached to the section at least at both ends of theconductors short length of less than 10 cm, for example woven mesh or strips.

If the metal or composite wiring system designed specifically for the purpose of EMC, is divided topass through a wall, for example, through ognepregraditelny barrier two metal sections should beinterconnected webs with low resistance, such as woven or mesh strips.

Figure 44.R22 ­ The connection metal sections

equal to 35 mFigure 44.R17B ­ Separation of power and data cablesduring long cable runs> 35 mFigure 44.R18 ­ Separation of cables in the wiring

444.6.3 Installation instructions444.7 Systems wirings

444.7.1 General requirements444.7.2 Design information

Figure 44.R19 ­ Laying cables in metal cable trays444.7.3 Installation instructions

Figure 44.R20 ­ continuous system consisting of metalcomponentsFigure 44.R21 ­ Location of cables inside the elements ofmetal structuresFigure 44.R22 ­ The connection metal sections

445 undervoltage protection445.1 General requirements

Annex A (informative). Explanation of the items 442.1 and 442.2Annex B (informative). Information about protection against overvoltage byusing surge protection devices (SPDs) are installed on overhead linesAnnex C (normative) / Determination of the conventional power line length d

Figure 44.Q ­ Examples d (1), d (2) and d (3) to determine dApplication YES (informative). Information on the reference line of nationaland interstate standards with international standards, used as reference in theapplication of international standardsBibliography

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Figure 44.R22 ­ The connection metal sections

444.7.3.2 metallic wiring systems

If the equipment attached unshielded cables are not exposed to low­frequency noise, the protectiveproperties of non­metallic electrical improved seal inside the single conductor is used as the shuntconductor equipotential. This conductor must be securely attached to the grounding device to which theequipment at both ends of the conductor, for example, by attaching to a metal shell of the cabinet.

Shunt potential equalization conductor should be selected under the terms of the resistance to themost common mode currents and the branch is damaged.

445 undervoltage protection

445.1 General requirements

445.1.1 If undervoltage or loss of voltage and its reconstitution can lead to dangerous situations forpeople or property, shall be provided appropriate precautions. Also, precautions should be provided, ifthe result of lowering the voltage may be damaged or parts of the installation of electrical equipment.The device of the undervoltage protection is not required if the damage to the installation or electricalequipment relates to the risk tolerance and there is no danger to people.

445.1.2 If the protected equipment allows for a short break power supply, poses no risk, triggering deviceundervoltage protection can be performed with a time delay.

445.1.3 When using contactors lag when opening and closing should not prevent an instantaneousshutdown of the protected equipment controls or safety devices.

Characteristics 445.1.4 devices undervoltage protection must comply with the requirements establishedin the standards for the launch and operation of protected equipment.

If re­enabling the security device may cause a dangerous situation, reclosing should not be automatic.

Annex A (informative). Explanation of the items 442.1 and 442.2

Annex A (informative)

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A.442.1 General

The rules set out in these two paragraphs are intended to ensure the safety of people and property inLV installations when an earth fault in the installation of HV.

Damage between systems of different voltages are those which can occur on the high­voltagesubstations, low voltage supply system of the distribution network, operating at high voltage. Suchdamage causes leakage current through the ground electrode, which is attached to the exposed conductiveparts of the substation.

Fault current depends on the impedance of the circuit on which the fault current flows, i.e. of howgrounded neutral to high voltage.

The fault current flowing through the ground electrode exposed conductive parts of the substation,causes an increase in the capacity of the substation exposed conductive parts with respect to the land,whose value depends on the value of the fault current and the resistance of the earth electrode exposedconductive parts of the substation.

Voltage damage may reach several thousand volts, depending on the type of earthing installations tocause:

­ A general increase in potential with respect to ground on the exposed conductive parts of the low­voltage system, which can lead to increased stress and damage to the contact voltage;

­ A general increase in potential with respect to ground in the low voltage, which can lead to failureof the low­voltage electrical equipment.

Usually the removal of damage in the high voltage requires a longer time than in the low voltage,since have a time delay relay for the selective protection against nuisance tripping current transients.

Off time of high­voltage switching devices are also more durable than the low­voltage devices.

This means that the resulting damage to the duration of the presence of voltage and the correspondingcontact voltage on exposed conductive parts of the low­voltage installations can be greater than requiredby regulations for low­voltage electrical installations.

Also, there is a risk of failure in the low­voltage substation and a consumer installation. Theprotective device under abnormal conditions, a voltage after transients may lead to difficulties or evenfailure in the open circuit.

If the damage to the high voltage installations should take into account the following conditions.

High­voltage systems with effectively earthed neutral

Such systems include a system which is connected to the neutral earth either directly or through a lowimpedance, and in which ground fault are removed within a relatively short time determined protectionequipment.

Accession to the neutral ground in substation is not considered appropriate.

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Capacitive currents are usually not taken into account.

High­voltage systems with isolated neutral.

The consideration received only single fault condition at the first earth fault between live parts ofhigh voltage and exposed conductive parts of the transformer substation.

This capacitive current can be turned off or disabled depending on its value and the protectionsystem.

Systems with high voltage arc suppression coil.

Arc suppression coil in the respective substation not taken into account.

If the closure system high voltage occurs between the high voltage conductor and the exposedconductive parts of the substation, having only small fault currents (differential currents typically of theorder of tens of amperes). These currents can persist for a long time.

A.442.2 Overvoltage in low­voltage ground fault on a high voltage

Figure 44.A2 derived from the curve pattern 20 IEC 60479­1 [18], and accepted as almost aninformed decision in IEC 61936­1 [1].

When considering the voltage values of damage should be considered:

a) low risk of earth fault in the high voltage system;

b) the fact that the contact voltage is always lower than the voltage of damage due to the presence of themain potential equalization specified in GOST R 50571.3, (sub 411.3.1.2), and additional earthing in theelectrical consumers and elsewhere.

The values given in ITU­T: 650V ­ for 0.2 and 430V ­ to automatically switch off with a time of 0.2seconds, slightly higher than the values indicated in Figure 44.A2.

Annex B (informative). Information about protection againstovervoltage by using surge protection devices (SPDs) are installedon overhead lines

Annex B (informative)

B.1 In accordance with 443.3.2.1 and note 1 to it the required level of surge protection can be achievedby installing surge protection devices in an installation, either directly or with the consent of the networkoperator on the routes of the distribution network of electricity supply.

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For example, can be applied the following measures:

a) in the case of an air distribution mains electricity overvoltage protection is established at points ofnetwork connections and mainly at the end of each distribution line having a length of more than 500 m.Overvoltage protection devices should be deployed along the distribution line supply power in the regionevery 500 m. The distance between the surge protective device must be less than 1000 m;

b) if the distribution mains electricity has been partially implemented as the air network, and partly as asnare laid in the ground, overvoltage protection in accordance with the listing of a) on overhead linesshould be installed at each point of transition from the overhead line to the cable laid in the ground;

c) The distribution network TN, feeding the electrical installations in which protection indirect contactautomatically cuts off power, grounding conductors overvoltage protection devices, connected to the lineconductors attached to the PEN­conductor or PE conductor;

d) The distribution network of the CT supply electrical installation, in which protection indirect contactautomatically cuts off power, surge protection device must be provided for line conductors and theneutral conductor. In a place where the neutral conductor is effectively grounded mains, install surgeprotectors in the neutral conductor is not required.

Table B.1 ­ Various possibilities for system IT (taking into account the first fault in the installation LV)

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Annex C (normative) / Determination of the conventional powerline length d

Annex C (normative)

Determining the length of the conventional power line

The configuration of the low voltage distribution network, the method of its ground insulation leveland nature of the phenomenon (inductive coupling, resistive coupling) leads to the choice of different lengths.

The method for calculating the conditional length proposed below represents the worst case.

Note ­ This simplified method is set to IEC 62305­2 [7].

GOST R 50571­4­44­2011 (IEC 60364­4­ .

Usually limited to a length of 1 km,

where ­ the length of the low­voltage overhead transmission line that feeds the building, less than 1km;

­ The length of unshielded low­voltage line supplying the building, laid in the ground, not morethan 1 km;

­ The length of high­voltage overhead line supplying the building, less than 1 km;

The length of transmission line laid in the ground, neglected.

Long shielded low­voltage lines, laid in the ground, neglected.

4 ­ reduction factor proportional to the impact of discharges between overhead lines and unshieldedcables in the ground, calculated for the earth resistivity of 250 ohms / m;

4 ­ the usual reduction factor for the transformer.

Figure 44.Q ­ Examples d (1), d (2) and d (3) to determine d

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Note ­ If the transformer is located inside the building GOSTR

0.

Figure 44.Q ­ Examples of use, and to determine the

Application YES (informative). Information on the reference lineof national and interstate standards with international standards,used as reference in the application of international standards

Application YES (informative)

Table DA.1

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Reference designation ofnational, interstate standards

Degree ofcompliance

Symbol and name of the international standard

GOST R 50571­1­2009 MOD IEC 60464­1: 2005 "Electrical installations of lowvoltage. Part 1: Basic provisions, assessment ofgeneral characteristics, terms and definitions"

GOST R 50571.3­2009 MOD IEC 60364­4­41: 2005 "Electrical installations of lowvoltage. Part 4­41. Requirements for safety.Protection against electric shock"

GOST R 50571.10­96 MOD IEC 60364­5­54­80 "Electrical installations ofbuildings. Part 5­54. Selection and installation ofelectrical equipment. Earthing and protectiveconductors"

GOST R 50571.16­2007 MOD IEC 60364­6: 2006 "Electrical installations of lowvoltage. Part 6: Tests"

GOST R 51317.2.5­2000 MOD IEC 61000­2­5­95 "compatibility of technicalequipment. Electromagnetic environment.Classification of electromagnetic interference on theplacements of technical means"

GOST R 51317.6.1­2006 MOD IEC 61000­6­1: 2005 "compatibility of technicalequipment. Immunity of technical equipment used inresidential and commercial areas and industrial areaswith low power consumption. Requirements and testmethods"

GOST R 51317.6.2­2007 MOD IEC 61000­6­2: 2005 "compatibility of technicalequipment. Immunity of technical equipment used inindustrial areas. Requirements and test methods"

GOST R 51317.6.3­2009 MOD IEC 61000­6­3: 2006 "compatibility of technicalequipment. Electromagnetic interference on thetechnical means used in residential and commercialareas and industrial areas with low power

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consumption. Limits and test methods"

GOST R 51317.6.4­2009 MOD IEC 61000­6­4: 2006 "compatibility of technicalequipment. Electromagnetic interference on thetechnical means used in industrial areas. Limits andtest methods"

GOST R IEC 60950­1­2009 IDT IEC 60950­1: 2005 "Information technologyequipment. Safety. Part 1: General requirements"

GOST 29322­92 MOD IEC 38­83 "standard voltage"

Note ­ This table uses the following conventions degree of compliance with the standards:

­ IDT ­ identical standards;

­ MOD ­ modified standards.

Bibliography

[1] IEC 61936­1 Power electrical voltages above 1 kV AC. Part 1: Generalrequirements

[2] IEC 60664­1: 2007 Insulation coordination for equipment within low voltage systems.Part 1: Principles, requirements and tests

[3] IEC 62305­1 Lightning protection. Part 1: General requirements

[4] IEC 62305­3 Lightning protection. Part 3: Physical damage to structures fromdamage and risk to life

[5] IEC 62305­4 Lightning protection. Part 4. Electrical and electronic systems inbuildings

[6] IEC 61643 (all parts) Low­voltage surge protectors

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[7] IEC 62305­2: 2006 Lightning protection. Part 2. Management torians *

________________* The text of the document corresponds to the original. ­ Note manufacturer's database.

[8] IEC 60364­5­51: 2005 Low­voltage electrical installations. Part 5­51. Selection andinstallation of electrical equipment. General rules

[9] IEC 60038 Voltage standard IEC

[10] IEC 60364­5­54 Low­voltage electrical installations. Part 5­54. Selection andinstallation of electrical equipment. Earthing, protective conductorand potential equalization

[eleven] IEC 62020: 1998 Electrical accessories. Control and measuring devices to determinethe residual current (RCM) household and similar purposes

[12] IEC 61558­2­1 Safety of power transformers, power supply units, reactors andsimilar products. Part 2­1. Specific requirements for the testsisolating transformers and power supply units comprising isolatingtransformers of general application

[13] IEC 61558­2­4 Safety of power transformers, power supply units and similarproducts. Part 2­4. Particular requirements for isolatingtransformers of general application

[14] IEC 61558­2­6 Safety of power transformers, power supply units and similarproducts. Part 2­6. Specific requirements for safety isolatingtransformers of general application

[15] IEC 61558­2­15 Safety of power transformers, power supply units and similarproducts. Part 2­15. Particular requirements for isolatingtransformers for the supply of medical facilities

[16] IEC 61386 (series) Conduit systems for electrical installations

[17] IEC 60364­5­52 Low­voltage electrical installations. Part 5­52. Selection andinstallation of electrical equipment. Wiring systems

12/9/2015 GOST R 50571­4­44­2011 Electrical low voltage. Part 4­44.

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[18] IEC 60479­1­2005 Impact of current on human beings and animals. Part 1: General

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