This standard specifies Part 4 of the "Electrical Installations in Buildings" standard: Protection against atmospheric transient overvoltages introduced by the power supply and distribution system and protection against operating overvoltages generated by equipment inside the electrical installation in safety protection. The following points should be considered: possible overvoltages in the power supply line section of the electrical installation; the expected lightning strike level in the local area; the location and characteristics of overvoltage protection devices. The purpose of the consideration is to reduce the possibility of accidents caused by overvoltage intrusion to a level allowed by the safety of personnel and property and the uninterrupted power supply of equipment. The transient overvoltage value depends on the type of power supply and distribution system (underground or overhead), the possibility of low-voltage protection devices installed on the incoming side of the power supply line end of the electrical installation, and the withstand voltage level of the power supply and distribution system. This standard provides guidance on two overvoltage protection measures, including self-suppression (relying on the insulation level of the system itself) or protection suppression (relying on overvoltage protection of installed protective electrical appliances). If overvoltage protection is not provided in accordance with the requirements of this standard, insulation coordination cannot be guaranteed, and an assessment of the danger of overvoltage should be made. GB 16895.12-2001 Electrical installations of buildings Part 4: Safety protection Chapter 44: Overvoltage protection Section 443: Atmospheric overvoltage or operating overvoltage protection GB16895.12-2001 Standard download decompression password: www.bzxz.net

GB 16895. 12
Article 443.2.2, Article 443.3.2.1 and Article 443.4.1 of this standard are mandatory, and the rest are recommended. This standard is equivalent to IEC60364-4-443: 1995 Electrical installations in buildings Part 4: Safety protection Chapter 44: Overvoltage protection Section 443: Atmospheric overvoltage or operational overvoltage protection and its first revision (1998). GB16895 "Electrical installations in buildings" is divided into the following 7 parts under the general title: Part 1: Scope, purpose and basic principles Part 2: Definitions
Part 3: Evaluation of general characteristics
Part 4: Safety protection
Part 5: Selection and installation of electrical equipment Part 6 Inspection
Part 7 Requirements for special installations or locations
Appendix A of this standard is a suggestive appendix.
This standard is proposed by the China Electrical Equipment Industry Association. This standard is under the jurisdiction of the National Technical Committee for Standardization of Electrical Installations in Buildings. The responsible drafting unit of this standard is: Tianjin Architectural Design Institute. The main drafters of this standard are: You Daqian, Yin Xiuwei, Li Fengli. This standard is entrusted to Tianjin Architectural Design Institute for interpretation. GB16895.12—2001
IEC Foreword
1) IEC International Electrotechnical Commission is a worldwide standardization organization, which is composed of all national electrotechnical committees (IEC National Committees). The purpose of IEC is to promote international cooperation on standardization issues in the electrical and electronic fields. For this purpose, among other activities, IEC publishes international standards. The preparation of standards is entrusted to technical committees; any IEC National Committee interested in the issues covered by the standards participates in this work. International, governmental and non-governmental organizations associated with IEC also participate in this work. IEC and the national standardization organization SO work closely under the conditions determined by the cooperation between the two organizations. 2) IEC formal resolutions or agreements on technical issues are developed by technical committees in which national committees with special interest in these issues participate, and express international consensus on the subject as far as possible. 3) These resolutions or agreements published in the form of standards, technical reports or guidelines are recommended for international use and are recognized by the national committees in this sense. 4) In order to promote international consensus, IEC national committees should undertake to apply IEC international standards to the greatest extent possible in their national or regional standards. Any differences between IEC standards and corresponding national or regional standards should be clearly stated in their national or regional standards.
International Standard IEC60364-4-443 was developed by IEC Technical Committee 64 (Electrical Installations in Buildings). This second edition cancels and replaces the first edition of 1990, forming a technical revision. The text of this standard is based on the following documents: DIS
64(CO)244/244A
Voting Report
64/777/RVD
In the voting report mentioned above, all the information on the voting for this standard can be found. GB 16B95.12
IEC Introduction
The purpose of this chapter is to specify some measures to limit transient overvoltages so that the risk of failure of electrical installations and electrical equipment connected to them is reduced to an allowable level. This measure is consistent with the insulation coordination requirements in IEC60664. IEC60664-1 requires each technical committee to specify an appropriate impulse withstand category (i.e. overvoltage category) for its equipment, that is, to determine the minimum impulse withstand voltage of the equipment according to the corresponding impulse withstand category based on the purpose of the equipment.
Note: According to Article 9 of IEC 60664-1, each technical committee should list relevant information and recommend that the rated impulse withstand voltage value and the means for providing the impulse withstand voltage be marked with the equipment.
IEC Amendment Document No. 1 Preface
This amendment was proposed by IEC Technical Committee 64 (Electrical Installations in Buildings). The text of this standard is based on the following documents: FDIS
64/1024/FDIS
Voting Report
64/1035/RVT
All information on the voting for this standard can be found in the voting report mentioned above. National Standard of the People's Republic of China
Electrical installations of buildings
Part 4: Protection for safety
Chapter 44: Protection against overvoltages
Section 443: Protection against overvoltages of atmospheric origin or due to switching443.1 General
443.1.1 Scope and purpose
GB 16895. 12- 2001
idt IEC 60364-4-443:1995
This standard specifies Part 4 of the "Electrical Installations in Buildings" standard: Protection against atmospheric transient overvoltages introduced by the power supply and distribution system and protection against operating overvoltages generated by equipment inside the electrical installation in safety protection. The following points should be considered: the overvoltage that may occur at the power supply line end of the electrical installation, the expected local lightning strike level, and the location and characteristics of the overvoltage protection device. The purpose of the consideration is to reduce the possibility of accidents caused by overvoltage intrusion to a level allowed by the safety of personnel and property and the uninterrupted power supply of the equipment. The transient overvoltage value depends on the type of power supply and distribution system (underground or overhead), the power supply side of the power supply line end of the electrical installation equipped with a low-voltage protection device The possibility and withstand voltage level of the power supply and distribution system. This standard provides guidance on two overvoltage protection measures, including self-suppression (relying on the insulation level of the system itself) or protective suppression (relying on overvoltage protection of installed protective devices). If overvoltage protection is not provided in accordance with the requirements of this standard, insulation coordination cannot be guaranteed, and an assessment of the danger of overvoltage should be made.
1 In this standard, the term "transient overvoltage" is used to define the meaning of lightning overvoltage in a statistical sense as follows: the statistical level of overvoltage refers to the overvoltage applied to the equipment due to a specific type of event (line power supply, reclosing, accident, residual discharge, etc.) in the system, and the probability of its peak voltage being exceeded is equal to a certain specified reference probability. 2 Regarding transient atmospheric overvoltage, no distinction is made between grounded and ungrounded systems. 3 Provisions for operating overvoltages introduced by the power grid and generated outside the electrical device are under preparation. 4 The provisions of this standard do not apply to telecommunications systems. 443.1.2 References
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. The versions shown are valid when the standard is published. All standards are subject to revision. Parties using this standard should investigate the possibility of using the latest version of the following standards. GB16895.11-2001 Electrical installations in buildings Part 4: Safety protection Chapter 41: Overvoltage protection Section 442: Protection of low-voltage electrical installations against temporary overvoltages and faults between the high-voltage system and earth (idt IEC 60364-4-442:1993)
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on November 21, 2001 and implemented on November 1, 2002
GB/T16935.1—[997
GB 16895. 12—2001
Insulation coordination for equipment in low-voltage systems Part 1: Principles, requirements and tests (idt IEC 60664-1:1992)
EC60038:1983 Standard voltage 11
IEC60050(826):1990 International Electrotechnical Dictionary (IEV) Chapter 826: Electrical installations in buildings IEC60364-5-534:1997 Electrical installations in buildings Part 5: Selection and installation of electrical equipment Chapter 53: Switchgear and controlgear Section 534: Overvoltage protection devices 3 [EC61024-1.1990 Lightning protection for buildings Part 1 i Basic principles 443.2 Division of impulse resistance categories (overvoltage categories) 443-2.1 Purpose of impulse resistance category (overvoltage category) Note See Table 44H
Impact resistance category is to distinguish different levels of equipment applicability based on the expected uninterrupted power supply to the equipment and the consequences of accidents that can be tolerated. By selecting the impulse resistance level of the equipment, the insulation coordination of the entire electrical installation is achieved, and the harmfulness of the fault is reduced to the allowable level to provide a basis for suppressing overvoltage.
The higher the impulse resistance category identification number, the higher the impulse resistance performance of the equipment and the more methods of suppressing overvoltage can be selected. The concept of impulse resistance category applies to equipment that is directly connected to the power line. Note: Atmospheric overvoltage will not decay significantly and naturally downstream in most electrical installations. Investigations have shown that the concept of probability encounter has been proven to be reasonable and practical.
443.2.2 Impulse resistance category (overvoltage category) Description [Class impulse resistance equipment is intended to be connected to the fixed electrical installation of the building. The protective measures should be outside this equipment, either fixed in the electrical installation or fixed between the electrical installation and this equipment to limit the transient overvoltage to a specified level. Class I impact-resistant equipment is equipment connected to the fixed electrical installation of a building. Note: Examples of this type of equipment: household appliances, portable tools and similar loads. Class II impact-resistant equipment is a component of a fixed electrical installation and other equipment that is expected to have a higher applicability category. Note: Examples of this type of equipment: distribution boards, circuit breakers, wiring systems (see TEC60050 (826) [TEVB26-06-01] of fixed electrical installations, including cables, busbars, junction boxes, switches, sockets), industrial equipment and certain other equipment, such as fixed motors permanently connected to fixed electrical installations. Class V impact-resistant equipment is equipment used at or near the power supply line terminal on the incoming side of the main distribution board of the building's electrical installation. Note: Examples of this type of equipment: electrical measuring instruments, primary overcurrent protection devices and filters. 443.3 Configuration of overvoltage suppression
This standard does not consider the overvoltage protection of low-voltage power supply lines or electrical installations in buildings subjected to direct lightning strikes (environmental influence AQ3), see JEC61024-1
2 In many cases, it is not necessary to suppress switching overvoltages, because the statistical evaluation of measurements shows that the probability of switching overvoltages exceeding the class overvoltage is very low. 3 The use of a hazard assessment method to replace the method of applying environmental influence AQ in this clause is being proposed. If it is necessary to install an electric shock protector according to the provisions of this standard, the following items shall be met: 443-3.1 Self-suppression
Adoption instructions:
1 This standard has been adopted as a national standard in a non-equivalent manner: GB1561998 Standard Voltage 2 When the 1EC: version of this standard was published, the standard was still in the draft stage. Therefore, the standard number in the IEC original text of this standard is LEC/1>1S361-5.534+1994. In 1997, IEC announced the official version of the standard. Therefore, the standard number in the technical standard was changed to IEC60364-5-534:1997. GB16895.12—2001
443.3.1.1 When the electrical installation is powered by a low-voltage underground system without overhead lines, the equipment impulse withstand voltage value specified in Table 44B is sufficient, and no additional atmospheric overvoltage protection is required. Note: Suspension insulated conductor cables with grounded metal shielding are considered to be equivalent to underground cables. 443.3.1.2 When the electrical installation is powered by a low-voltage overhead line or contains a low-voltage overhead line, and the external environmental impact is AQ1 (thunderstorm number <25/year), no additional atmospheric overvoltage protection is required. Note
1 When higher reliability is required or higher danger is expected (such as fire), additional atmospheric overvoltage protection may be considered. 2 According to IEC61024-1, 25 thunderstorm days per year is equivalent to 2.24 thunderstorm days/km, year, which is derived from the following formula: N, — 0. 04T1 z5
Where: N, — a lightning rate, that is, the number of lightning strikes per km* per year: T — the number of thunderstorm days per year.
3 In some cases, overvoltage protection measures can replace the external environmental influence conditions AQ based on the results of risk assessment. 443.3.2 Protection suppression
443.3.2.1 When the electrical installation is powered by overhead lines or lines containing overhead lines, and the local lightning activity meets the external influence conditions AQ2 (thunderstorm days> 25 days/year), atmospheric overvoltage protection should be installed. The protection level of the protection device should not be higher than the Class 1 overvoltage level listed in Table 44B.
1 The level of overvoltage is suppressed by overvoltage protection devices installed on overhead lines near the power supply input end of the electrical installation (see Appendix A) or in the electrical installation of the building.
2 Special protection measures may be considered where reliability is required to be high or where higher risks (such as fire) are expected and where the ability to withstand risks is particularly low according to the purpose of the electrical installation.
443.3.2.2 Under the conditions of 443.3.2.1, the atmospheric overvoltage protection of the electrical installation of the building may be taken by the following measures: Install a surge protector with a protection level of [class] in accordance with 1EC60364-5-534. - Or provide at least equivalent voltage attenuation by other means. Note: The coordination guidelines for series-stage surge protectors are under preparation. 443.4 Selection of equipment in electrical installations
443.4.1 The selection of equipment shall ensure that its rated impulse withstand voltage value is not less than the impulse withstand voltage requirement value listed in Table 44B. The product standards committee for installation materials is responsible for proposing the rated impulse withstand voltage requirements specified in Table 44B in the relevant standards. Note: The rated impulse withstand voltage is the impulse withstand voltage value of the equipment or a part of the equipment specified by the manufacturer to indicate its specified insulation overvoltage withstand capability (according to Article 1.3.9.2 of [EC 60664-1]. 443.4.2 If a higher degree of fault damage is allowed, equipment with a lower impulse withstand voltage value listed in Table 44B can be used. Surge protectors and their various protection measures should be able to safely withstand the temporary overvoltages described in GB16895.112001. Table 441 Required rated impulse withstand voltage values ​​for equipment Nominal voltage for electrical equipment:
With neutral point
Three-phase system
230/400
277/480
Single-phase system
120~240
Power supply for electrical equipment
Equipment at the line end
(Impact resistance category N:)
Required impulse resistance Voltage value bzxZ.net
Equipment for distribution and final circuits
(impact resistance category 1)
Electrical appliances
Impact resistance category)
Equipment with special protection
(impact resistance category 1)
Nominal voltage of electrical installations'
400/690
*According to IEC60038.1983.
For special equipment engineering.
GB 16895.12—2001
Table 44B (end)
Required impulse resistance voltage values
For product standard committees for equipment connected to the line. 6
Quickly determined by system engineers
For product standard committees for installation materials and certain special product standard committees. For use by power supply departments and system engineers (see 443.2.2). 2.5
GB16895.12—2001
(Reminder Appendix)
Guidelines for the application of protection suppression in overhead according to Note 1 in 443.3.2.1 are given in 443.3.2.Under the conditions listed in item 1, protection against overvoltage levels can be obtained by installing surge protectors directly in the electrical installation or, with the agreement of the network operator, by installing surge protectors on the overhead lines of the supply and distribution network. For example, the following measures can be taken:
a) In the case of an overhead supply and distribution network, overvoltage protection should be established at the nodes of the network, especially at the end of each line with a length of more than 500 m. Overvoltage protection devices should be installed every 500 m along the supply and distribution line. The distance between overvoltage protection devices should be less than 1 000 m. b) If part of the supply and distribution network is an overhead line and part is an underground line, overvoltage protection should be provided in the overhead network in accordance with item a) above, and overvoltage protection should be provided at the transition point from the overhead line to the underground cable. c) In electrical installations supplied by a TN distribution network, where protection for contact is provided by automatic disconnection of the power supply, the earthing conductor of the overvoltage protection device connected to the phase conductor is connected to the PEN conductor or to the PE conductor. d) In electrical installations supplied by the TT distribution network, where protection for indirect contact is provided by automatic power cut-off, overvoltage protection devices shall be provided for phase conductors and neutral conductors. Where the neutral conductor of the supply network is directly earthed, it is not necessary to install overvoltage protection devices for the neutral conductor.
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