Translated English of Chinese Standard: GB7251.1-2013 www.chinesestandard.net Sales@ChineseStandard.net GB NATIONAL STANDARD OF THE PEOPLE S REPUBLIC OF CHINA ICS 29.130 K 31 GB 7251.1-2013 / IEC 60439-1:2011 Replacing GB 7251.1-2005 Low-voltage switchgear and controlgear assemblies - Part 1: General rules (IEC 61439-1:2011, IDT) Issued on: December 31, 2013 Implemented on: January 13, 2015 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration of the People's Republic of China. www.chinesestandard.net Page 1 of 179
Table of Contents Foreword... 8 Introduction... 13 1 Scope... 15 2 Normative references... 16 3 Terms and definitions... 19 3.1 General terms... 19 3.2 Constructional units of assemblies... 22 3.3 External design of assemblies... 23 3.4 Structural parts of assemblies... 25 3.5 Conditions of installation of assemblies... 27 3.6 Insulation characteristics... 28 3.7 Protection against electric shock... 32 3.8 Characteristics... 35 3.9 Verification... 39 3.10 Manufacturer/user... 40 4 Symbols and abbreviations... 41 5 Interface characteristics... 41 5.1 General... 41 5.2 Voltage ratings... 41 5.3 Current ratings... 42 www.chinesestandard.net Page 2 of 179
5.4 Rated diversity factor (RDF)... 43 5.5 Rated frequency (fn)... 44 5.6 Other characteristics... 44 6 Information... 45 6.1 assembly designation marking... 45 6.2 Documentation... 46 6.3 Device and/or component identification... 46 7 Service conditions... 47 7.1 Normal service conditions... 47 7.2 Special service conditions... 48 7.3 Conditions during transport, storage and installation... 49 8 Constructional requirements... 49 8.1 Strength of materials and parts... 49 8.2 Degree of protection provided by an assembly enclosure... 51 8.3 Clearances and creepage distances... 52 8.4 Protection against electric shock... 54 8.5 Incorporation of switching devices and components... 63 8.6 Internal electrical circuits and connections... 65 8.7 Cooling... 68 8.8 Terminals for external conductors... 68 9 Performance requirements... 70 www.chinesestandard.net Page 3 of 179
9.1 Dielectric properties... 70 9.2 Temperature rise limits... 71 9.3 Short-circuit protection and short-circuit withstand strength... 72 9.4 Electromagnetic compatibility (EMC)... 74 10 Design verification... 74 10.1 General... 74 10.2 Strength of materials and parts... 76 10.3 Degree of protection of assemblies... 81 10.4 Clearances and creepage distances... 82 10.5 Protection against electric shock and integrity of protective circuits 82 10.6 Incorporation of switching devices and components... 84 10.7 Internal electrical circuits and connections... 84 10.8 Terminals for external conductors... 84 10.9 Dielectric properties... 84 10.10 Verification of temperature rise... 88 10.11 Short-circuit withstand strength... 102 10.12 Electromagnetic compatibility (EMC)... 110 10.13 Mechanical operation... 110 11 Routine verification... 111 11.1 General... 111 11.2 Degree of protection of enclosures... 112 www.chinesestandard.net Page 4 of 179
11.3 Clearances and creepage distances... 112 11.4 Protection against electric shock and integrity of protective circuits... 112 11.5 Incorporation of built-in components... 112 11.6 Internal electrical circuits and connections... 112 11.7 Terminals for external conductors... 112 11.8 Mechanical operation... 113 11.9 Dielectric properties... 113 11.10 Wiring, operational performance and function... 113 Annex A (normative) Minimum and maximum cross-section of copper conductors suitable for connection to terminals for external conductors (see 8.8)... 122 Annex B (normative) Method of calculating the cross-sectional area of protective conductors with regard to thermal stresses due to currents of short duration... 123 Annex C (informative) User information template... 124 Annex D (informative) Design verification... 130 Annex E (informative) Rated diversity factor... 132 E.1 General... 132 E.2 Rated diversity factor of an assembly... 132 E.3 Rated diversity factor of a group of outgoing circuits... 132 E.4 Rated diversity factor and intermittent duty... 137 Annex F (normative) Measurement of clearances and creepage distances 6... 139 www.chinesestandard.net Page 5 of 179
F.1 Basic principles... 139 F.2 Use of ribs... 139 Annex G (normative) Correlation between the nominal voltage of the supply system and the rated impulse withstand voltage of the equipment... 144 Annex H (informative) Operating current and power loss of copper conductors... 146 Annex I... 149 Annex J (normative) Electromagnetic compatibility (EMC)... 150 J.1 General... 150 J.2 Terms and definitions... 150 Annex K (normative) Protection by electrical separation... 158 K.1 General... 158 K.2 Electrical separation... 158 K.3 Class II equipment or equivalent insulation... 161 Annex L (informative) Clearances and creepage distances for North American region... 162 Annex M (informative) North American temperature rise limits... 163 Annex N (normative) Operating current and power loss of bare copper bars... 164 Annex O (informative) Guidance on temperature rise verification... 167 O.1 General... 167 O.2 Temperature-rise limits... 167 O.3 Test... 168 www.chinesestandard.net Page 6 of 179
O.4 Calculation... 170 O.5 Design rules... 170 Annex P (normative) Verification of the short-circuit withstand strength of busbar structures by comparison with a tested reference design by calculation... 174 P.1 General... 174 P.2 Terms and definitions... 174 P.3 Method of verification... 175 P.4 Conditions for application... 176 Bibliography... 178 www.chinesestandard.net Page 7 of 179
Foreword All technical content of this Part is mandatory. GB 7251 Low-voltage switchgear and controlgear assemblies includes the following parts: - Part 0: Guidance to specifying assemblies - Part 1: General rules - Part 2: Power switchgear and controlgear assemblies - Part 3: Distribution boards operated by unskilled persons 1) - Part 4: Assemblies for construction sites (ACS) 2) - Part 5: Particular requirements for assemblies for power distribution in public networks - Part 6: Busbar trunking systems (busways) - Part 7: Assemblies for specific applications such as marinas, camping sites, market squares, electric vehicles charging stations This Part is Part 1 of GB 7251. This Part was drafted according to the rules given in GB/t 1.1-2009. This Part replaces GB 7251.1-2005 Low-voltage switchgear and controlgear assemblies - Part 1: Type-tested and partially type-tested assemblies. Compared this Part with GB 7251.1-2005, main technical changes are as follows: - DELETE the dual functions of the original GB 7251.1/IEC 60439-1 as the product standard itself and the General standard of GB 7251/IEC 60439 series; - GB 7251.1 is only a General standard for the GB 7251 series of products; - GB 7251.12 replaced the original GB 7251.1 product standards; 1 ) Being declared a project. 2) Being declared a project. www.chinesestandard.net Page 8 of 179
- GB/T 11021-2007 Electrical insulation - Thermal classification (IEC 60085:2004, IDT) - GB/T 11026 (all parts) Electrical insulating materials - Properties of thermal endurance [IEC 60216 (all parts)] - GB 14048.1-2012 Low-voltage switchgear and controlgear - Part 1: General rules (IEC 60947-1:2011, MOD) - GB/T 16422.2-1999 Plastics - Methods of exposure to laboratory light sources Part 2: Xenon-arc sources (ISO 4892-2:1994, IDT) - GB 16895 (all parts) Electrical installations of buildings [IEC 60364 (all parts)] - GB 16895.3-2004 Electrical installations of buildings - Part 5-54: Selection and erection of electrical equipment - Earthing arrangements, protective conductors and protective bonding conductors (IEC 60364-5-54:2002, IDT) - GB 16895.4-1997 Electrical installations of buildings - Part 5: Selection and erection of electrical equipment Chapter 53: Switchgear and controlgear (IEC 60364-5-53:1994, IDT) - GB 16895.6-2000 Electric installations of buildings - Part 5: Selection and erection of electrical equipment - Chapter 52: Wiring systems (IEC 60364-5-52:1993, IDT) - GB/T 17626.2-2006 Electromagnetic compatibility (EMC ) - Testing and measurement techniques - Electrostatic discharge immunity test (IEC 61000-4- 2:2001, IDT) - GB/T 17626.28-2006 Electromagnetic compatibility(emc) - Testing and measurement techniques - Variation of power frequency immunity test (IEC 61000-4-28:2002, IDT) - GB/T 17626.3-2006 Electromagnetic compatibility - Testing and measurement techniques - Radiated radio-frequency electromagnetic field immunity test (IEC 61000-4-3:2006, IDT) - GB/T 17626.6-2008 Electromagnetic compatibility - Testing and measurement techniques - Immunity to conducted disturbances induced by radio-frequency fields (IEC 61000-4-6:2006, IDT) - GB/T 17627 (all parts) High-voltage test techniques for low-voltage equipment [IEC 61180 (all parts)] - GB 17799.4-2001 Electromagnetic compatibility - Generic standards - Emission STANDARD for industrial environments (IEC 61000-6-4:1997, IDT) www.chinesestandard.net Page 10 of 179
- GB/T 20641-2006 Empty enclosures for Low-voltage switchgear and controlgear assemblies - General requirements (IEC 62208:2002, IDT) This Part makes the following editorial modifications: - CHANGE this standard BY this Part ; - USE the decimal symbol. to replace the symbol, ; - DELETE the foreword of the international standard. This Part was proposed by China Electrical Equipment Industry Association. This Part shell be under the jurisdiction of National Technical Committee on Standardization of Low-voltage Switchgear and Controlgear Assemblies (SAC/TC 266). Drafting organizations of this Part: Tianjin Electric Drive Design Institute Co., Ltd., Changshu Switch Manufacturing Co., Ltd. (former Changshu Switch Factory), Power Transmission and Distribution Branch of Shanghai Electric Group Co., Ltd., Chuan Kai Electric Co., Ltd., Tianjin Tianchuan Electronic Control & Power Distribution Co., Ltd., China Quality Certification Center, National Electric Control Equipment Quality Supervision and Inspection Center, Gansu Institute of Electrical Science and Technology (former Tianshui Great Wall Electric Test Research Institute), Guangzhou Baiyun Electrical Equipment Co., Ltd., Anhui Xinlong Electric Appliance Co., Ltd., Shanghai Kawamura Electric Co., Ltd., Zhuhai Guangle Power Busway Co., Ltd., Zhejiang Electric (Hangzhou) Group Co., Ltd., Jiangsu Borui Electric Co., Ltd., Zhongfa Electric Co., Ltd., Fatai Electric (Jiangsu) Co., Ltd., Daquan Group Co., Ltd., Hangzhou Hangkai Electric Co., Ltd., Chengdu Kexing Power Electric Co., Ltd., Hangzhou Yanmei Assembly Manufacturing Co., Ltd., Guangdong Zhujiang Switchgear Co., Ltd., Huapeng Group Co., Ltd., Jiuchuan Group Co., Ltd., Jiangxi Hengzhu Electric Cabinet Lock Co., Ltd., Yuyao Power Equipment Repair Plant, Shanghai Nanhua Lanling Electric Co., Ltd., Suzhou Electric Appliance Research Institute Co., Ltd., Fujian Senda Electric Co., Ltd., Zhejiang Fangyuan Electrical Equipment Testing Co., Ltd., Linhai Yaoming Power Equipment Company, Ningbo Yaohua Electric Technology Co., Ltd., Zhenjiang Siemens Bus Co., Ltd., Tianjin Tianchuan Yingke Science and Technology Development Co., Ltd., Jilin Longding Electric Co., Ltd., Jiangsu Modern Power Technology Co., Ltd., China Coal Electric Co., Ltd., Zhenjiang Moeller Electric Appliance Co., Ltd. Main drafters of this Part: Zhong Mingzhen, Wang Yang, Liu Jie, Guan Ruiliang, Wang Chunling, Xia Jinhui, Cui Jing, Chen Xin, Mo Weiqiang, Hu Xinming, Wang Yi, Yuan Yuchao, Cheng Jun, Zheng Gungle, Lin Bibao, Zhu Wentang, Yu Chunsheng, Jin Minyi, Pei Jun, Mao Shuiquan, Zeng Qingcai, Huang Wukang, Zhang Bocheng, Chen Yunhua, Liu Xiaolin, Zhong Jijiang, Zhou Qihong, Zhou Fubo, Hu Delin, Chen Zeyin, www.chinesestandard.net Page 11 of 179
Low-voltage switchgear and controlgear assemblies - Part 1: General rules 1 Scope This Part of the GB 7251 lays down the definitions and states the service conditions, construction requirements, technical characteristics and verification requirements for low-voltage switchgear and controlgear assemblies (hereafter referred to as assemblies) (see 3.1.1). This Part cannot be used alone to specify an assembly or used for a purpose of determining conformity, assemblies shall comply with the relevant part of the GB 7251 series; Parts 2 onwards. This Part applies to low-voltage switchgear and controlgear assemblies only when required by the relevant assembly standard as follows: - assemblies for which the rated voltage does not exceed 1 000 V in case of a.c. or 1 500 V in case of d.c.; - stationary or movable assemblies with or without enclosure; - assemblies intended for use in connection with the generation, transmission, - distribution and conversion of electric energy, and for the control of electric energy consuming equipment; - assemblies designed for use under special service conditions, for example in ships and in rail vehicles provided that the other relevant specific requirements are complied with; NOTE 1: Supplementary requirements for assemblies in ships are covered by GB 7251. - assemblies designed for electrical equipment of machines provided that the other relevant specific requirements are complied with. NOTE 2: Supplementary requirements for assemblies forming part of a machine are covered by the GB 7251 series. This Part applies to all assemblies whether they are designed, manufactured and verified on a one-off basis or fully standardised and manufactured in quantity. www.chinesestandard.net Page 15 of 179
The manufacture and/or assembly may be carried out other than by the original manufacturer (see 3.10.1). This Part does not apply to individual devices and self-contained components, such as motor starters, fuse switches, electronic equipment, etc. which will comply with the relevant product standards. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 2423.17-2008 Basic environmental testing procedures - Part 2-11: Tests - Test Ka: Salt mist (IEC 60068-2-11:1981, IDT) GB/T 2423.2-2008 Environmental testing - Part 2-2: Tests - Test B: Dry heat (IEC 60068-2-2:2007, IDT) GB/T 2423.4-2008 Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic (12 + 12 h cycle) (IEC 60068-2-30:2005, IDT) GB/T 4025-2012 Basic and safety principles for man-machine interface, marking and identification - Coding principles for indicators and actuators (IEC 60073:2002, IDT) GB/T 4205-2010 Basic and safety principles for man-machine interface, marking and identification - Actuating principles (IEC 60447:2004, IDT) GB 4208-2008 Degrees of protection provided by enclosures (IP Code) (IEC 60529:1989, IDT) GB/T 5013.3-2008 Rubber insulated cables - Rated voltages up to and including 450/750 V- Part 3: Heat resistant silicone insulated cables (IEC 60245-3:1994, IDT) GB/T 5169.10-2006 Fire Hazard testing - Part 2-10: Glowing/hot-wire based test methods - Glow-wire apparatus and common test procedure (IEC 60695-2-10:2000, IDT) GB/T 5169.11-2006 Fire hazard testing - Part 2-11: Glowing/hot-wire based test methods - Glow-wire flammability test method for end-products (IEC 60695-2- 11:2000, IDT) GB/T 5269.5-2008 Fire hazard testing - Part 11-5: Test flames - Needle-flame test method - Apparatus, confirmatory test arrangement and guidance (IEC 60695-11- 5:2004, IDT) www.chinesestandard.net Page 16 of 179
GB/T 9341-2008 Plastics - Determination of flexural properties (ISO 178:2001, IDT) GB/T 16895.10-2010 Low-voltage electrical installations - Part 4-44: Protection for safety - Protection against voltage disturbances and electromagnetic disturbances (IEC 60364-4-44:2007, IDT) GB 16895.21-2011 Low-voltage electrical installations - Part 4-41: Protection for safety - Protection against electric shock (IEC 60364-4-41:2005, IDT) GB/T 16935.1-2008 Insulation coordination for equipment within low-voltage systems - Part 1: Principles, requirements and tests (IEC 60664-1:2007, IDT) GB/T 17626.11-2008 Electromagnetic compatibility (EMC) - Part 4-11: Testing and measurement techniques - Voltage dips, short interruptions and voltage variations immunity tests (IEC 61000-4-11:2004, IDT) GB/T 17626.13-2006 Electromagnetic compatibility (EMC) - Part 4-13: Testing and measurement techniques - Harmonics and interharmonics including mains signalling at a.c. power port, low-frequency immunity tests (IEC 61000-4-13:2002 3), IDT) GB/T 17626.4-2008 Electromagnetic compatibility (EMC) - Part 4-4: Testing and measurement techniques - Electrical fast transient/burst immunity test (IEC 61000-4-4:2004, IDT) GB/T 17626.5-2008 Electromagnetic compatibility (EMC) - Part 4-5: Testing and measurement techniques - Surge immunity test (IEC 61000-4-5:2005, IDT) GB/T 20138-2006 Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code) (IEC 62262:2002, IDT) GB/T 24276-2009 A method of temperature-rise assessment by extrapolation for partially type-tested assemblies (PTTA) of low-voltage switchgear and controlgear (IEC/TR 60890:2007 + IEC/TR 60890:1087/Amd1:1995, IDT) IEC 60085:2007 Electrical insulation - Thermal evaluation and designation IEC 60216 (all parts) Electrical insulating materials - Properties of thermal endurance IEC 60227-3:1993 Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V - Part 3: Non-sheathed cables for fixed wiring 3) There is a unified version 1.1 (2009), which includes IEC 61000-4-13 (2002) and its amendment 1 (2009). www.chinesestandard.net Page 17 of 179
IEC 60245-4:1994, Rubber insulated cables - Rated voltages up to and including 450/750 V- Part 4: Cords and flexible cables IEC 60364 (all parts), Low-voltage electrical installations IEC 60364-5-52:2009 Low-voltage electrical installations - Part 5-52: Selection and erection of electrical equipment - Wiring systems IEC 60364-5-53:2001 Electrical installations of buildings - Part 5-53: Selection and erection of electrical equipment - Isolation, switching and control IEC 60364-5-54:2011 Low-voltage electrical installations - Part 5-54: Selection and erection of electrical equipment - Earthing arrangements and protective conductors IEC 60439 (all parts) Low-voltage switchgear and controlgear assemblies IEC 60445:2010 Basic and safety principles for man-machine interface, marking and identification - Identification of equipment terminals, conductor terminations and conductors IEC 60865-1:1993 Short-circuit currents - Calculation of effects - Part 1: Definitions and calculation methods IEC 60947-1:2007 Low-voltage switchgear and controlgear - Part 1: General rules IEC 61000-4-2:2008 Electromagnetic compatibility (EMC) - Part 4-2: Testing and measurement techniques - Electrostatic discharge immunity test IEC 61000-4-3:2006 Electromagnetic compatibility (EMC) - Part 4-3: Testing and measurement techniques - Radiated, radio frequency, electromagnetic field immunity test 4) IEC 61000-4-6:2008 Electromagnetic compatibility (EMC) - Part 4-6: Testing and measurement techniques - Immunity to conducted disturbances, induced by radiofrequency fields IEC 61000-4-8:2009 Electromagnetic compatibility (EMC) - Part 4-8: Testing and measurement techniques - Power frequency magnetic field immunity test EC 61000-6-4:2006 Electromagnetic compatibility (EMC) - Part 6-4: Generic standards - Emission standard for industrial environments 4) 4) There is a unified version 3.2 (2010), which includes IEC 61000-4-3 (2006) and its amendment 1 (2007) and amendment 2 (2009). 5) There is a unified version 2.1 (2011), which includes IEC 61000-4-4 (2006) and its amendment 1 (2010). www.chinesestandard.net Page 18 of 179
IEC 61082-1 Preparation of documents used in electrotechnology - Part 1: Rules IEC 61180 (all parts) High-voltage test techniques for low-voltage equipment IEC/TS 61201:2007 Use of conventional touch voltage limits - Application guide IEC 61439 (all parts) Low-voltage switchgear and controlgear assemblies IEC 62208 Empty enclosures for low-voltage switchgear and controlgear assemblies - General requirements IEC 81346-1 Industrial systems, installations and equipment and industrial products - Structuring principles and reference designations - Part 1: Basic rules IEC 81346-2 Industrial systems, installations and equipment and industrial products - Structuring principles and reference designations - Part 2: Classification of objects and codes for classes IEC/CISPR 11:2009 Industrial, scientific and medical equipment - Radio-frequency disturbance characteristics - Limits and methods of measurement 6) IEC/CISPR 22 Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement ISO 179 (all parts) Plastics - Determination of Charpy impact strength ISO 2409:2007 Paints and varnishes - Cross-cut test ISO 4628-3:2003 Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and size of defects, and of intensity of uniform changes in appearance - Part 3: Assessment of degree of rusting ISO 4892-2:2006 Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc lamps 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 General terms 3.1.1 6) There is a unified version 5.1 (2010), which includes CISPR 11 (2009) and its amendment 1 (2010). www.chinesestandard.net Page 19 of 179
Bibliography [1] GB/T 2900.50-2008 Electrotechnical terminology - Generation transmission and distribution of electricity - General [2] GB/T 2900.57-2008 Electrotechnical terminology - Generation transmission and distribution of electricity - Operation [3] GB/T 2900.71-2008 Electrotechnical terminology - Electrical installations [4] GB/T 2900.73-2008 Electrotechnical terminology - Earthing and protection against electric shock [5] GB/T 2900.8-2009 Electrotechnical terminology - Insulators [6] GB/T 2900.83-2008 Electrotechnical terminology - Electrical and magnetic devices [7] GB/T 3956-2008 Conductors of insulated cables [8] GB/T 4207-2003 Method for determining the comparative and the proof tracking indices of solid insulating materials under moist conditions [9] GB/T 5023.4-2008 Polyvinyl chloride insulated cables of rated voltages up to and including 450/750V - Part 4:Sheathed cables for fixed wiring [10] GB 5226 (all parts) Safety of machinery - Electrical equipment of machines [11] GB 5226.1-2008 Electrical safety of machinery - Electrical equipment of machines - Part 1: General requirements [12] GB/T 7061-2003 General specification for low-voltage switchgear and controlgear assemblies in ships [13] GB/T 17045-2008 Protection against electric shock - Common aspects for installation and equipment [14] GB 17625.2-2007 Electromagnetic compatibility (EMC) - Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current 16 A per phase and not subject to conditional connection [15] GB/Z 17625.3-2000 Electromagnetic compatibility - Limits - Limitation of voltage fluctuations and flicker in low-voltage power supply systems for equipment with rated current greater than 16A [16] GB/T 24277-2009 A method for assessing the short-circuit withstand Strength of partially type-tested assemblies (PTTA) [17] GB/Z 25842.1-2010 Low-voltage switchgear and controlgear - Overcurrent protective devices www.chinesestandard.net Page 178 of 179
- Part 1: Application of short-circuit ratings GB 7251.1-2013 [18] GB/Z 25842.2-2012 Low-voltage switchgear and controlgear - Overcurrent protective devices - Part 2: Selectivity under over-current conditions [19] IEC 60038, IEC standard voltages [20] IEC 60050-441:1984, International Electrotechnical Vocabulary - Chapter 441: Switchgear, controlgear and fuses [21] IEC 60079 (all parts), Explosive atmospheres [22] IEC 60417-SN:2011, Graphical symbols for use on equipment [23] IEC 60502-1:2004, Power cables with extruded insulation and their accessories for rated voltages from 1 kv (U m = 1.2 kv) up to 30 kv (U m = 36 kv) - Part 1: Cables for rated voltages of 1 kv (U m = 1.2 kv) and 3 kv (U m = 3.6 kv) [24] IEC 60947 (all parts), Low-voltage switchgear and controlgear [25] IEC 61000-3-2:2005, Electromagnetic compatibility (EMC) - Part 3-2: Limits - Limits for harmonic current emissions (equipment input current 16 A per phase) [26] IEC 61000-3-11, Electromagnetic compatibility (EMC) - Part 3-11: Limits - Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems - Equipment with rated current 75 A and subject to conditional connection [27] IEC 61000-3-12, Electromagnetic compatibility (EMC) - Part 3-12: Limits - Limits for harmonic currents produced by equipment connected to public low-voltage systems with input current 16 A and 75 A per phase [28] IEC 61000-6-1, Electromagnetic compatibility (EMC) - Part 6-1: Generic standards - Immunity for residential, commercial and light-industrial environments [29] IEC 61000-6-2, Electromagnetic compatibility (EMC) - Part 6-2: Generic standards - Immunity for industrial environments [30] IEC 61000-6-3, Electromagnetic compatibility (EMC) - Part 6-3: Generic standards - Emission standard for residential, commercial and light-industrial environments [31] IEC/TR 61912-1:2007, Low-voltage switchgear and controlgear - Overcurrent protective devices - Part 1: Application of short-circuit ratings [32] IEC 61241 (all parts), Electrical apparatus for use in the presence of combustible dust [33] DIN 43671:1975, Copper busbars; design for continuous current END www.chinesestandard.net Page 179 of 179