标准编号:	GB/T 3836.8-2021
中文名称:	爆炸性环境 第8部分：由“n”型保护的设备
英文名称:	Explosive atmospheres—Part 8: Equipment protection by type of protection “n”
中标分类:	K35    防爆电器
行业分类:	GB    国家标准
ICS分类:	29.260.20 29.260.20    易爆环境用电气设备 29.260.20
发布机构:	国家市场监督管理总局 国家标准化管理委员会
发布日期:	2021-10-11
实施日期:	2022-5-1
标准状态:	valid
替代旧标准:	GB 3836.8-2014 爆炸性环境 第8部分: 由n型保护的设备
翻译语言:	英文
文件格式:	PDF
中文字符数:	27000 字
翻译价格(元):	1735.0
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This document is drafted in accordance with the rules given in the GB/T 1.1-2020 Directives for Standardization — Part 1: Rules for the Structure and Drafting of Standardizing Documents. This part is Part 8 of GB/T 3836 Explosive Atmospheres. The following parts of GB/T 3836 have been published: — Part 1: Equipment — General Requirements; — Part 2: Equipment Protection by Flameproof Enclosures “d”; — Part 3: Equipment Protection by Increased Safety “e”; — Part 4: Equipment Protection by Intrinsic Safety "i"; — Part 5: Equipment Protection by Pressurized Enclosure “p”; — Part 6: Equipment Protection by Oil Immersion “o”; — Part 7: Equipment Protection by Powder Filling “q”; — Part 8: Equipment Protection by Type of Protection “n”; — Part 9: Equipment Protection by Type of Protection “m”; — Part 11: Material Characteristics for Gas and Vapour Classification — Test Methods and Data; — Part 12: Material Characteristics for Combustible Dusts — Test Methods; — Part 13: Equipment Repair, Overhaul and Reclamation; — Part 14: Classification of Areas — Explosive Gas Atmosphere; — Part 15: Electrical Installations Design, Selection and Erection; — Part 16: Electrical Installations Inspection and Maintenance; — Part 17: Equipment Protection by Pressurized Room “p” and Artificially Ventilated Room “v”; — Part 18: Intrinsically Safe Electrical Systems; — Part 20: Equipment with Equipment Protection Level (EPL) Ga; — Part 21: Application of Quality Systems for Equipment Manufacture; — Part 22: Protection of Equipment and Transmission System using Optical Radiation; — Part 23: Group I, Category EPL Ma Equipment Intended to Remain Functional in Atmospheres Endangered by Firedamp and/or Coal Dust — Part 24: Equipment Protection by Special Protection “s”; — Part 25: Requirements for Process Sealing between Flammable Process Fluids and Electrical Systems; — Part 26: Electrostatic Hazards — Guidance; — Part 27: Electrostatic Hazards — Test; — Part 28: Non-electrical Equipment for Potentially Explosive Atmospheres — Basic Method and Requirements; — Part 29: Non-electrical Equipment for Explosive Atmospheres — Constructional Safety “c”, Control of Ignition Source “b”, Liquid Immersion “k; — Part 30: Equipment and Components in Explosive Atmospheres in Underground Mines; — Part 31: Equipment Dust Ignition Protection by Enclosure “t”; — Part 32: Intrinsically Safe Systems with Electronically Controlled Spark Duration Limitation; — Part 33: Equipment in Adverse Service Conditions; — Part 34: Equipment Assemblies; — Part 35: Classification of Areas for Explosive Dust Atmospheres; This standard replaces GB 3836.8-2014 Explosive Atmospheres — Part 8: Equipment Protection by Type of Protection “n” in whole, and the following technical deviations have been made with respect to the GB 3836.8-2014: — The range of internal working voltage is modified (see Clause 1; Clause 1 of Edition 2014); — The non-sparking device “nA” is deleted and transferred to GB/T 3836.3, "ec” (see Clause 3 of Edition 2014); — The enclosed-break device “nC” is deleted and transferred to GB/T 3836.2, "dc” (see Clause 3 of Edition 2014); — The term and definition of hermetically-sealed device “nC” is modified (see Clause 3; Clause 3 of Edition 2014); — The term and definition of normally sparking device is added (see Clause 3); — The provisions of small components are deleted (see 5.2 of Edition 2014); — The requirements for connection facilities and terminal compartments are deleted (see Clause 7 of Edition 2014); — The supplementary requirements for non-sparking electrical rotating machines are deleted (see Clause 8 of Edition 2014); — The supplementary requirements for non-sparking fuses and fuse assemblies are deleted for instrumentation (see Clause 9 of 2014 Edition); — The supplementary requirements for non-sparking plugs and sockets are deleted (see Clause 10 of Edition 2014); — The supplementary requirements for non-sparking luminaires are deleted (see Clause 11 of Edition 2014); — The supplementary requirements for equipment incorporating non-sparking cells and batteries are deleted (see Clause 12 of Edition 2014). — The supplementary requirements for non-sparking low power equipment are deleted (see Clause 13 of Edition 2014); — The supplementary requirements for non-sparking current transformers are deleted (see Clause 14 of Edition 2014); — The requirements for other non-sparking electrical equipment are deleted (see Clause 15 of Edition 2014); — The general supplementary requirements for equipment producing arcs, sparks or hot surfaces are deleted (see Clause 16 of Edition 2014). — The requirements for enclosed-break devices are deleted (see Clause 17 of Edition 2014); — The voltage and current limiting for non-incendive components are added (see 7.2); — The requirements for sealed devices are modified (see Clause 9; Clause 19 of Edition 2014); — The requirements that the COT for device use in a luminaire shall be at least 20 K are deleted (see 19.5 of Edition 2014); — The requirements for in accordance with the relevant industrial standards are added (see 10.2.1); — The requirements for cells and batteries are added (see 10.2.2); — The requirements for cable glands and conduit entries are modified (see 10.2.3; 20.2.2 of Edition 2014); — The requirements for gasketed windows are modified (see 10.2.5.2; 20.2.4.2 of Edition 2014); — The documentation requirements for gasket and seal requirements are added (see 10.2.6); — The requirements for non-resilient seals are modified (see 10.2.7; 20.2.6 of Edition 2014); — The requirements for internal fans with restricted breathing enclosures are added (see 10.2.9); — The type tests for enclosed break devices and non incendive components are deleted (see 22.4 of Edition 2014); — The preparation of non-incendive component samples is added (see 11.1.1); — The requirements for electric strength test are modified (see 12.1; 22.5.2 of Edition 2014); — The type tests of enclosed devices, screws, starters, lamps, ignitors and triggers are deleted (see Clause 22 of Edition 2014); — All tests for batteries are deleted (see 22.11 and 22.12 of Edition 2014); — All tests for electric machines are deleted (22.13 of Edition 2014); — The requirements for routine tests are modified (see Clause 12; Clause 23 of Edition 2014); — The requirements for markings are modified (see Clause 13; Clause 24 of 2014 edition); — The requirements for documentation are modified (see Clause 14; and Clause 25 of Edition 2014); — The requirements for instructions are added (see Clause 15); This document has been redrafted and modified adoption of International Standard IEC 60079-15:2017 Explosive Atmospheres — Part 15: Equipment Protection by Type of Protection “n”. The technical deviations between this document and the International Standard IEC 60079-15:2017, together with their justifications, are given below: — The adjustments on technical deviations have been made for the normative references of this document to adapt to the technical conditions in China, which are mainly reflected in Clause 2 "Normative References”, with the following specific content:  IEC 60079-0 is replaced by GB/T 3836.1 which is redrafted and modified adoption of the international standard (see Clause 1, etc.);  IEC 60079-7 is replaced by GB/T 3836.3 which is redrafted and modified adoption of the international standard (see 10.2.2, etc.); — The reference column with IEC 60079-0:2011 (Ed.6.0) in Table 1 of IEC 60079-15:2017 is deleted to be consistent with the Chinese standard version. For the purposes of this document, the following editorial changes have also been made: — In order to be consistent with the current standard series, the name of this document is modified to Explosive Atmospheres — Part 8: Equipment Protection by Type of Protection “n”; — Note 1 in Table 1 regarding standard version information is modified; — The note regarding GB/T 2900.35 is added (see Clause 3); — Bibliography is modified. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights. This document was proposed by China Electrical Equipment Industry Association. This document is under the jurisdiction of National Technical Committee 9 on Explosion Protected Electrical Apparatus of Standardization Administration of China (SAC/TC 9). The previous editions of this document and documents replaced by this document are as follows: — The first edition was issued in 1987 as GB 3836.8-1987, first edition was revised in 2003, and second revision was issued in 2014; — This is the second revised edition.   Introduction GB/T 3836 Explosive Atmospheres is prepared in order to establish the basic technical requirements for equipment used in explosive atmospheres and its application, covering the design, manufacture, inspection, selection, installation, inspection, maintenance, repair and site classification of equipment used in explosive atmospheres, and adopts the form of partial standards, including but not limited to the following parts: — Part 1: Equipment — General Requirements; — Part 2: Equipment Protection by Flameproof Enclosures “d”; — Part 3: Equipment Protection by Increased Safety “e”; — Part 4: Equipment Protection by Intrinsic Safety "i"; — Part 5: Equipment Protection by Pressurized Enclosure “p”; — Part 6: Equipment Protection by Oil Immersion “o”; — Part 7: Equipment Protection by Powder Filling “q”; — Part 8: Equipment Protection by Type of Protection “n”; — Part 9: Equipment Protection by Type of Protection “m”; — Part 11: Material Characteristics for Gas and Vapour Classification — Test Methods and Data; — Part 12: Material Characteristics for Combustible Dusts — Test Methods; — Part 13: Equipment Repair, Overhaul and Reclamation; — Part 14: Classification of Areas — Explosive Gas Atmosphere; — Part 15: Electrical Installations Design, Selection and Erection; — Part 16: Electrical Installations Inspection and Maintenance; — Part 17: Equipment Protection by Pressurized Room “p” and Artificially Ventilated Room “v”; — Part 18: Intrinsically Safe Electrical Systems; — Part 20: Equipment with Equipment Protection Level (EPL) Ga; — Part 21: Application of Quality Systems for Equipment Manufacture; — Part 22: Protection of Equipment and Transmission System using Optical Radiation; — Part 23: Group I, Category EPL Ma Equipment Intended to Remain Functional in Atmospheres Endangered by Firedamp and/or Coal Dust — Part 24: Equipment Protection by Special Protection “s”; — Part 25: Requirements for Process Sealing between Flammable Process Fluids and Electrical Systems; — Part 26: Electrostatic Hazards — Guidance; — Part 27: Electrostatic Hazards — Test; — Part 28: Non-electrical Equipment for Potentially Explosive Atmospheres — Basic Method and Requirements; — Part 29: Non-electrical Equipment for Explosive Atmospheres — Constructional Safety “c”, Control of Ignition Source “b”, Liquid Immersion “k; — Part 30: Equipment and Components in Explosive Atmospheres in Underground Mines; — Part 31: Equipment Dust Ignition Protection by Enclosure “t”; — Part 32: Intrinsically Safe Systems with Electronically Controlled Spark Duration Limitation; — Part 33: Equipment in Adverse Service Conditions; — Part 34: Equipment Assemblies; — Part 35: Classification of Areas for Explosive Dust Atmospheres; Type of protection “n” is one of the most important explosion-proof types. In terms of standardization of this technology, China formulated GB 3836.8-1987 in 1987, and then revised it twice by IEC 60079-15 in 2003 and 2014. Since the release and implementation of the standard, there has been a certain new development in type of protection “n” explosion-proof technology. In terms of international standards, the current version of the corresponding standard is IEC 60079-15:2017, and its content and structure have been greatly adjusted. The requirements of non-sparking device "nA” and enclosed-break device “nC” have been transferred to other relevant standards, and the main technical content can also be applied to the situation of China. In order to adapt to the development of explosion-proof technology and industry and be consistent with the development of international standards, it is necessary to revise GB 3836.8. Based on the main technical content of IEC 60079-15:2017, appropriate modifications have been made in this revision to adapt to the specific situation in China. This standard is a supplement and modification of GB/T 3836.1 as a specific type of protection part. Explosive Atmospheres — Part 8: Equipment Protection by Type of Protection “n” 1 Scope This document specifies requirements for the construction, testing and marking for Group II electrical equipment with type of protection “n” which includes: sealed devices “nC”, hermetically sealed devices “nC”, non-incendive components “nC” and restricted breathing enclosures “nR” intended for use in explosive gas atmospheres. This document is applicable to electrical equipment where the rated input voltage does not exceed 15 kV r.m.s. AC or DC including where the internal working voltages of the Ex product exceeds 15 kV, for example starters for HID luminaires. This document supplements and modifies the general requirements of GB/T 3836.1, except as indicated in Table 1. Where a requirement of this document conflicts with a requirement of GB/T 3836.1, the requirement of this document will take precedence. Table 1 Relationship of this document to GB/T 3836.1 Clause of GB/T 3836.1 GB/T 3836.1 clause application to this document Clause/Sub-clause number (informative) Clause/Sub-clause title (nominative) Protected sparking “nC” Restricted breathing “nR” 3 Terms and definitions Applies Applies 4 Equipment grouping 4.1 General Excluded Excluded 4.2 Group I Excluded Excluded 4.3 Group II Applies Applies 4.4 Group III Excluded Excluded 4.5 Equipment for a particular explosive atmosphere Applies Applies 5 Temperatures 5.1 Environmental influences Applies Applies 5.2 Service temperature Applies Applies 5.3 Maximum surface temperature 5.3.1 Determination of maximum surface temperature Applies Applies 5.3.2 Limitation of maximum surface temperature 5.3.2.1 Group I electrical equipment Excluded Excluded 5.3.2.2 Group II electrical equipment Applies Applies 5.3.2.3 Group III electrical equipment Excluded Excluded 5.3.3 Small component temperature for Group I and Group II electrical equipment Applies Excluded 5.3.4 Component temperature of smooth surfaces for Group I or Group II electrical equipment Applies Excluded 6 Requirements for all electrical apparatus 6.1 General Applies Applies 6.2 Mechanical strength of equipment Applies Applies 6.3 Opening time of equipment enclosure Excluded Applies 6.4 Circulating currents in enclosures (e.g. of large electrical machines) Applies Applies 6.5 Gasket retention Applies Applies 6.6 Electromagnetic and ultrasonic radiating equipment Applies Applies 7 Non-metallic enclosures or non-metallic parts of enclosures 7.1 General 7.1.1 Applicability Applies Applies 7.1.2 Specification of materials Applies Applies 7.2 Thermal endurance 7.2.1 Tests for thermal resistance Applies Applies 7.2.2 Material selection Applies Applies 7.2.3 Alternative qualification for elastomeric sealing O-rings Applies Applies 7.3 Resistance to ultraviolet light Applies Applies 7.4 Electrostatic charges on external non-metallic materials 7.4.1 Applicability Applies Applies 7.4.2 Avoidance of a build-up of electrostatic charge for Group I or Group II equipment Applies Applies 7.4.3 Avoidance of a build-up of electrostatic charge for Group III equipment Excluded Excluded 7.5 Attached external conductive parts Applies Applies 8 Metallic enclosures and metallic parts of enclosures 8.1 Material composition Applies Applies 8.2 Group I equipment Excluded Excluded 8.3 Group II equipment Applies Applies 8.4 Group III equipment Excluded Excluded 8.5 Copper alloy Applies Applies 9 Fasteners 9.1 General Applies Applies 9.2 Special fasteners Excluded Excluded 9.3 Holes for special fasteners Excluded Excluded 9.4 Hexagon socket set screws Excluded Excluded 10 Interlocking devices Excluded Excluded 11 Insulating bushings Applies Applies 12 (Reserved for future use) Excluded Excluded 13 Ex components Applies Applies 14 Connection facilities Applies Applies 15 Connection facilities for earthing and bonding conductors Applies Applies 16 Entries into enclosures Applies Applies 17 Supplementary requirements for electric machines Excluded Excluded 18 Supplementary requirements for switchgear Excluded 18.1 Flammable dielectric Excluded Applies 18.2 Disconnectors Excluded Applies 18.3 Group I equipment – Provisions for locking Excluded Excluded 1 8.4 Doors and covers Excluded Applies 19 Supplementary requirements for fuses Excluded Excluded 20 Supplementary requirements for plugs and sockets for field wiring connection 20.1 General Applies Applies 20.2 Explosive gas atmospheres Excluded Excluded 20.3 Explosive dust atmospheres Excluded Excluded 20.4 Energized plugs Applies Applies 21 Supplementary requirements for luminaires 21.1 General Applies Applies 21.2 Covers for luminaires of EPL Mb, EPL Gb or EPL Db Excluded Excluded 21.3 Covers for luminaires of EPL Gc or EPL Dc Applies Applies 21.4 Sodium lamps Applies Applies 22 Supplementary requirements for caplights and handlights 22.1 Group I caplights Excluded Excluded 22.2 Group II and Group III caplights and handlights Excluded Applies 23 Equipment incorporating cells and batteries Applies Applies 23.12 Replacement battery pack Applies Applies 24 Documentation Modified Modified 25 Compliance of prototype or sample with documents Applies Applies 26 Type tests Applies Applies 26.4 Tests of enclosures 26.4.1 Order of tests 26.4.1.1 Metallic enclosures, metallic parts of enclosures and glass or ceramic parts of enclosures Applies Applies 26.4.1.2 Non-metallic enclosures or non-metallic parts of enclosures 26.4.1.2.1 General Applies Applies 26.4.1.2.2 Class I equipment Excluded Excluded 26.4.1.2.3 Group II and Group III equipment Applies Applies 26.4.2 Impact resistance test Applies Applies 26.4.3 Drop test Applies Applies 26.4.4 Acceptance criteria Applies Applies 26.4.5 Degrees of protection provide by enclosure (IP) Applies Applies 26.5 Thermal tests 26.5.1 Temperature measurement Applies Applies 26.5.1.1 General Applies Applies 26.5.1.2 Service temperature Applies Applies 26.5.1.3 Maximum surface temperature Applies Applies 26.5.2 Thermal shock test Applies Applies 26.5.3 Small component ignition test (Group I and Group II) Applies Excluded 26.6 Torque test for insulating bushings Applies Applies 26.7 Non-metallic enclosures or non-metallic parts of enclosures 26.7.1 General Applies Applies 26.7.2 test temperature Applies Applies 26.8 Test for thermal endurance to heat Applies Applies 26.9 Test for thermal endurance to cold Applies Applies 26.10 Ultraviolet (UV) resistance test 26.10.1 General Applies Applies 26.10.2 Light exposure Applies Applies 26.10.3 Acceptance criteria Applies Applies 26.11 Test for resistance to chemical agents for Group I electrical equipment Excluded Excluded 26.12 Earth continuity Applies Applies 26.13 Surface resistance test of parts of enclosures of non-metallic materials Applies Applies 26.14 Measurement of capacitance 26.14.1 General Applies Applies 26.14.2 Test procedure Applies Applies 26.15 Verification of ratings of ventilating fans Excluded Excluded 26.16 Alternative qualification of elastomeric sealing O-rings Applies Applies 26.17 Transferred charge test Applies Applies 27 Routine test Applies Applies 28 Manufacturers responsibility Applies Applies 29 Marking 29.1 Applicability Applies Applies 29.2 Location Applies Applies 29.3 General Applies Applies 29.4 Ex marking for explosive gas atmospheres Applies Applies 29.5 Ex marking for explosive dust atmospheres Excluded Excluded 29.6 Combined types (or levels) of protection Applies Applies 29.7 Multiple types of protection Applies Applies 29.8 Ga equipment using two independent Gb types (or levels) of protection Excluded Excluded 29.9 Boundary wall Excluded Excluded 29.10 Ex components Applies Applies 29.11 Small Ex equipment and small Ex components Applies Applies 29.12 Extremely small equipment and extremely small Ex components Applies Applies 29.13 Warning markings Applies Applies 29.14 Battery Applies Applies 29.15 Electrical machines operated with a converter Applies Applies 29.16 Examples of marking Examples Examples 30 Instructions 30.1 General Applies Applies 30.2 Cells and batteries Applies Applies 30.3 Electric machines Excluded Excluded 30.4 Ventilating fans Excluded Excluded 30.5 Cable glands Applies Applies Annex A Supplementary requirements for Ex cable glands Applies Applies Annex B Requirements for Ex components Applies Applies Annex C Example of rig for resistance to impact test Informative annex Informative annex Annex D Motors supplied by converters Informative annex Informative annex Annex E Temperature evaluation of electric machines Informative annex Informative annex Annex F Guideline flowchart for tests of non-metallic enclosures or non-metallic parts of enclosures Informative annex Informative annex Annex G Guidance flowchart for tests of cable glands Informative annex Informative annex Annex H Shaft voltages resulting in motor bearing or shaft brush sparking. Discharge energy calculation Informative annex Informative annex Annex I Special requirements for Group I electrical equipment Excluded Excluded Appendix J Inspection procedure for obtaining Ex certificate Applies Applies Applies: This requirement of GB/T 3836.1 is applied without change. Excluded: This requirement of GB/T 3836.1 does not apply. Modified: This requirement of GB/T 3836.1 is modified as detailed in this document. Note 1: The clause number in the above table is shown for information only. The applicable requirements of GB/T 3836.1 are identified by the clause title which is normative. This document was written against the specific requirements of GB/T 3836.1. Note 2: A shaded row in the above table indicates that this is a clause heading. In cases where the applicability is the same for all of the sub-clauses the ‘Applies’ or ‘Excluded’ is listed in the heading row and the sub-clauses are not expanded. Where the application of the individual sub-clauses may be different, these are expanded in the above table and the applicability for each is listed. Note 3: A non-incendive component is limited in use to the particular circuit for which it has been shown to be non-ignition capable and, therefore, cannot be separately assessed as complying with this document. 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 3836.1 Explosive Atmospheres — Part 1: Equipment — General Requirements (GB 3836.1-2021, IEC 60079-0:2017, MOD) GB/T 3836.3 Explosive Atmospheres — Part 3: Equipment Protection by Increased Safety “e” (GB/T 3836.3-2021, IEC 60079-7:2015, MOD) 3 Terms and Definitions For the purposes of this document, the terms and definitions given in GB/T 3836.1 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC: http://www.electropedia.org/; — ISO: http://www.iso.org/obp. Note: Additional definitions applicable to explosive atmospheres can be found in GB/T 2900.35. 3.1 devices and components “nC” 3.1.1 hermetically-sealed device “nC” device which is so constructed that it cannot be opened and is sealed effectively by fusion to prevent entry of an external atmosphere 3.1.2 non-incendive component “nC” component having contacts for making or breaking a specified ignition capable circuit but in which the contacting mechanism is designed and constructed so that the component is not capable of causing ignition of the specified explosive gas atmosphere Note: The enclosure of the non-incendive component is not intended to either exclude the explosive gas atmosphere or contain an explosion. This is usually applied to specially constructed switch contacts that are mechanically designed to quench any arc or spark so that they are not a source of ignition. 3.1.3 sealed device “nC” device which is so constructed that it cannot be opened during normal service and is sealed effectively to prevent entry of an external atmosphere 3.2 normally sparking device device with spacings in line with the industrial requirements and which produces arcs and sparks during normal operating conditions Note: Normally sparking devices include switches, relays, and contactors not otherwise Ex protected. 3.3 restricted-breathing enclosure “nR” enclosure that is designed to restrict the entry of gases, vapours and mists 3.4 sealing device device employing a method other than encapsulation to prevent the flow of a gas or a liquid between equipment and a conduit or between separate parts of the equipment by providing sealing facilities Note: This device is not a device covered by GB/T 3836.25. 3.5 separation shortest distance through solid insulating material between two conductive parts 3.6 test port facility to test the integrity of restricted breathing equipment in the field after installation, during initial inspection and during maintenance 3.7 type of protection "n" type "n” type of protection applied to electrical equipment such that, in normal operation and in certain specified regular expected occurrences, it is not capable of igniting a surrounding explosive gas atmosphere Note: Additionally, the requirements of this document are intended to ensure that a malfunction capable of causing ignition is not likely to occur. 4 General 4.1 Equipment grouping and temperature classification Equipment grouping and temperature classification shall be in accordance with the equipment grouping and temperature classification clauses of GB/T 3836.1. 4.2 Potential ignition sources In normal operation and in certain regular expected occurrences specified by this document, the equipment shall not: a) produce an operational arc or spark unless that arc or spark is prevented from causing ignition of a surrounding explosive atmosphere by one of the methods described in Clauses 7 to 10; b) develop a maximum surface temperature in excess of the maximum value appropriate to the temperature class of the equipment, unless the temperature of the surface or hot spot is prevented from causing ignition of a surrounding explosive atmosphere by one of the methods described in Clauses 7 to 10 as appropriate, or is otherwise shown to be safe as specified in Clause 5. 4.3 Equipment requirements Equipment or components which in normal operation produce arcs, sparks or hot surfaces which otherwise would be capable of igniting a surrounding atmosphere shall be protected against causing ignition by one or more of the following methods, all of which provide Equipment Protection Level Gc: a) non-incendive component (see Clause 7); b) hermetically sealed device (see Clause 8); c) sealed device (see Clause 9); d) restricted-breathing enclosure (see Clause 10). 5 Maximum Surface Temperature The maximum surface temperature shall be determined in accordance with the determination of maximum temperature classification requirements of GB/T 3836.1. The surface to be considered shall be the external surface of the equipment including the surface of internal parts of non-incendive components to which the explosive gas atmosphere has access. Note: This is often the outside surface of type of protection “nC” components located within level of protection “ec” equipment. 6 Requirements for Electrical Equipment 6.1 General Electrical equipment with type of protection "n" shall comply with the requirements of this document and the applicable parts of GB/T 3836.1 for the method(s) of protection used. 6.2 Electric strength insulation from earth or frame Where the electrical circuits within the equipment are not connected directly to the frame of the equipment or not intended to be connected to the frame in service, the insulation or separation distance used shall withstand without breakdown one of the following tests:

Foreword II Introduction VIII 1 Scope 2 Normative References 3 Terms and Definitions 4 General 5 Maximum Surface Temperature 6 Requirements for Electrical Equipment 7 Requirements for Non-incendive Components 8 Requirements for Hermetically Sealed Devices 9 Requirements for Sealed Devices 10 Requirements for Restricted-breathing Enclosures 11 Type Test 12 Routine Verifications and Routine Tests 13 Marking 14 Documentation 15 Instructions Bibliography

爆炸性环境 第8部分：由“n”型保护的设备 1 范围 本文件规定了Ⅱ类爆炸性气体环境由“n”型保护的电气设备的结构、试验和标志的要求。防爆型式包括“nC”密封装置、“nC”气密装置、“nC”非点燃元件和“nR”限制呼吸外壳。 本文件适用于额定输入电压不超过15 kV交流有效值或直流的电气设备，Ex产品内部的工作电压可以超过15 kV，例如HID灯具的启动器。 本文件是对GB/T 3836.1通用要求的补充和修改，如表1所示。当本文件的要求与GB/T 3836.1的要求有冲突时，本文件的要求优先。 表1 本文件与GB/T 3836.1的关系 GB/T 3836.1的条款 GB/T 3836.1条款对本文件的适用性 章条号 (资料性) 章条标题 (规范性) 火花保护 “nC” 限制呼吸 “nR” 3 术语和定义 适用 适用 4 设备分类 4.1 总则 排除 排除 4.2 I类 排除 排除 4.3 Ⅱ类 适用 适用 4.4 Ⅲ类 排除 排除 4.5 特定爆炸性气体环境用设备 适用 适用 5 温度 5.1 环境影响 适用 适用 5.2 工作温度 适用 适用 5.3 最高表面温度 5.3.1 最高表面温度的测定 适用 适用 5.3.2 最高表面温度的限制 5.3.2.1 I类电气设备 排除 排除 5.3.2.2 Ⅱ类电气设备 适用 适用 5.3.2.3 Ⅲ类电气设备 排除 排除 5.3.3 I类或Ⅱ类电气设备的小元件温度 适用 排除 5.3.4 I类或Ⅱ类电气设备光滑表面的元件温度 适用 排除 6 对所有设备的要求 6.1 总则 适用 适用 6.2 设备的机械强度 适用 适用 6.3 设备外壳打开时间 排除 适用 6.4 外壳中的环流(如大型电机) 适用 适用 6.5 衬垫保持 适用 适用 6.6 电磁能和超声波能辐射设备 适用 适用 7 非金属外壳和外壳的非金属部件 7.1 通则 7.1.1 适用范围 适用 适用 7.1.2 材料要求 适用 适用 7.2 热稳定性 7.2.1 热稳定性试验 适用 适用 7.2.2 材料选择 适用 适用 7.2.3 O形弹性密封圈替换 适用 适用 7.3 耐紫外线 适用 适用 7.4 外部非金属材料上的静电电荷 7.4.1 适用性 适用 适用 7.4.2 避免静电电荷在I类或Ⅱ类设备上积聚 适用 适用 7.4.3 避免静电电荷在Ⅲ类设备上积聚 排除 排除 7.5 附属外部导电部件 适用 适用 8 金属外壳和外壳的金属部件 8.1 材料成分 适用 适用 8.2 I类设备 排除 排除 8.3 Ⅱ类设备 适用 适用 8.4 Ⅲ类设备 排除 排除 8.5 铜合金 适用 适用 9 紧固件 9.1 通则 适用 适用 9.2 特殊紧固件 排除 排除 9.3 特殊紧固件的孔 排除 排除 9.4 内六角紧定螺钉 排除 排除 10 联锁装置 排除 排除 11 绝缘套管 适用 适用 12 (预留将来使用) 排除 排除 13 Ex元件 适用 适用 14 连接件 适用 适用 15 接地导体或等电位导体连接件 适用 适用 1 6 外壳的引入装置 适用 适用 17 电机的补充要求 排除 排除 18 开关的补充要求 排除 18.1 可燃性绝缘介质 排除 适用 18.2 隔离开关 排除 适用 18.3 I类设备——联锁措施 排除 排除 1 8.4 门和盖 排除 适用 19 熔断器的补充要求 排除 排除 20 现场布线连接用外部插头、插座和连接器的补充要求 20.1 通则 适用 适用 20.2 爆炸性气体环境 排除 排除 20.3 爆炸性粉尘环境 排除 排除 20.4 带电插头 适用 适用 21 灯具的补充要求 21.1 通则 适用 适用 21.2 EPL Mb、EPL Gb或EPL Db级灯盖 排除 排除 21.3 EPL Gc或EPL Dc级灯盖 适用 适用 21.4 钠灯 适用 适用 22 帽灯和手提灯的补充要求 22.1 I类帽灯 排除 排除 22.2 Ⅱ类和Ⅲ类帽灯和手提灯 排除 适用 23 装有电池的设备 适用 适用 23.12 可更换电池包 适用 适用 24 文件 修改 修改 25 试样或样机与文件的一致性 适用 适用 26 型式试验 适用 适用 26.4 外壳试验 26.4.1 试验顺序 26.4.1.1 金属外壳、外壳的金属部件和外壳的玻璃或陶瓷部件 适用 适用 26.4.1.2 非金属外壳或外壳的非金属部件 26.4.1.2.1 通则 适用 适用 26.4.1.2.2 I类设备 排除 排除 26.4.1.2.3 II类和Ⅲ类设备 适用 适用 26.4.2 抗冲击试验 适用 适用 26.4.3 跌落试验 适用 适用 26.4.4 合格判据 适用 适用 26.4.5 外壳防护等级(IP) 适用 适用 26.5 热试验 26.5.1 温度测定 适用 适用 26.5.1.1 通则 适用 适用 26.5.1.2 工作温度 适用 适用 26.5.1.3 最高表面温度 适用 适用 26.5.2 热剧变试验 适用 适用 26.5.3 小元件点燃试验(I类和Ⅱ类) 适用 排除 26.6 绝缘套管扭转试验 适用 适用 26.7 非金属外壳和外壳的非金属部件 26.7.1 通则 适用 适用 26.7.2 试验时的温度 适用 适用 26.8 耐热试验 适用 适用 26.9 耐寒试验 适用 适用 26.10 耐紫外线(UV)试验 26.10.1 通则 适用 适用 26.10.2 光暴露 适用 适用 26.10.3 合格判据 适用 适用 26.11 I类设备的耐化学试剂试验 排除 排除 26.12 接地连续性 适用 适用 26.13 非金属材料外壳部件的表面电阻测定 适用 适用 26.14 电容测量 26.14.1 通则 适用 适用 26.14.2 试验程序 适用 适用 26.15 风扇额定值验证 排除 排除 26.16 O形弹性密封圈替换评定 适用 适用 26.17 转移电荷试验 适用 适用 27 例行试验 适用 适用 28 制造商责任 适用 适用 29 标志 29.1 适用性 适用 适用 29.2 标志位置 适用 适用 29.3 通则 适用 适用 29.4 爆炸性气体环境防爆标志 适用 适用 29.5 爆炸性粉尘环境防爆标志 排除 排除 29.6 混(复)合型防爆型式 适用 适用 29.7 多种防爆型式 适用 适用 29.8 使用两个独立Gb级防爆型式(保护等级)的Ga级设备 排除 排除 29.9 边界墙 排除 排除 29.10 Ex元件 适用 适用 29.11 小型Ex设备和Ex元件 适用 适用 29.12 超小型Ex设备和Ex元件 适用 适用 29.13 警告标志 适用 适用 29.14 电池 适用 适用 29.15 由变频器控制的电机 适用 适用 29.16 标志示例 示例 示例 30 使用说明书 30.1 通则 适用 适用 30.2 电池说明书 适用 适用 30.3 电机说明书 排除 排除 30.4 通风扇说明书 排除 排除 30.5 电缆引入装置说明书 适用 适用 附录A 电缆引入装置的附加要求 适用 适用 附录B 对Ex元件的要求 适用 适用 附录C 抗冲击试验装置示例 资料性附录 资料性附录 附录D 连接到变频器的电机 资料性附录 资料性附录 附录E 电机温升评估 资料性附录 资料性附录 附录F 非金属外壳或外壳的非金属部件试验的指导流程图 资料性附录 资料性附录 附录G 电缆引入装置试验的指导流程图 资料性附录 资料性附录 附录H 轴电压导致电机轴承或电刷火花放电能量计算 资料性附录 资料性附录 附录I I类电气设备的特殊要求 排除 排除 附录J 取得防爆合格证的检验程序 适用 适用 “适用”：GB/T 3836.1的要求适用，没有修改。 “排除”：GB/T 3836.1的要求不适用。 “修改”：GB/T 3836.1的要求在本文件有修改。 注1：表中的章条号仅作为信息。GB/T 3836.1适用的要求由章条标题确定，属于规范性内容。本文件按照GB/T 3836.1—9021的具体要求编写。 注2：表中的阴影行表示标题。在标题栏里的“适用”或“排除”适用于所有子条款，而且子条款不再扩展。个别子条款的适用性与标题栏不相同时，在表格中列出每条适用与否。 注3：非点燃元件限定只能用在已经表明不能点燃的特定电路中，因此不单独按照本文件的要求评定。 2规范性引用文件 下列文件中的内容通过文中的规范性引用而构成本文件必不可少的条款。其中，注日期的引用文件，仅该日期对应的版本适用于本文件；不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 3836.1 爆炸性环境 第1部分：设备 通用要求(GB/T 3836.1—2021，IEC 60079—0：2017，MOD) GB/T 3836.3 爆炸性环境 第3部分：由增安型“e”保护的设备(GB/T 3836.3—2021，IEC 60079—7：2015，MOD) 3术语和定义 GB/T 3836.1界定的以及下列术语和定义适用于本文件。 ISO和IEC在以下地址维护用于标准化的术语数据库： ——IEC：http：//www.electropedia.org/； ——ISO：http：//www.iso.org/obp。 注：适用于爆炸性环境的其他定义见GB/T 2900.35。 3.1 “nC”装置和元件devices and components “nC” 3.1.1 “nC”气密装置hermetically-sealed device “nC” 结构上使其不能打开，并且通过熔接有效地密封阻止外部大气进入的装置。 3.1.2 “nC”非点燃元件non—incendive component “nC” 接通或断开具有规定的点燃能力的电路的触头，但是接触机构的设计和结构使其不能够点燃规定的爆炸性气体环境的元件。 注：非点燃元件的外壳不用于阻止爆炸性气体环境或承受爆炸。通常适用于特殊结构的开关触点.这些开关触点的机械设计能够熄灭电弧或火花，使它们不会成为点燃源。 3.1.3 “nC”密封装置 sealed device “nC” 结构上使其在正常运行期间不能打开，并且有效地密封阻止外部大气进入的装置。 3.2 普通火花装置normally sparking device 在正常运行条件下产生电弧和火花，电气间隙和爬电距离是符合工业要求的装置。 注：普通火花装置包括未采用防爆保护的开关、继电器和接触器。 3.3 “nR”限制呼吸外壳restricted-breathing enclosure “nR” 设计成能限制气体、蒸气和薄雾进入的一种外壳。 3.4 密封装置sealing device 不用浇封面采用密封件，阻止气体或液体在设备和导管之间或设备的不同部件之间流动的装置。 注：该装置不是GB/T 3836.25包括的装置。 3.5 间距 separation 两导电部件之间通过固体绝缘材料的最短距离。 3.6 测试接口test port 安装后，在初始检查和维护期间，在现场测试限制呼吸设备完整性的装置。 3.7 防爆型式“n” type of protection “n” “n”型 电气设备的一种防爆型式，采用该型式的电气设备，在正常运行时和本文件规定的一些常规预期条件下，不能点燃周围的爆炸性气体环境。 注：本文件的要求用于确保不出现能引起点燃的故障。 4 通则 4.1 设备类别和温度组别 设备类别和温度组别应符合GB/T 3836.1设备类别和温度组别的规定。 4.2潜在点燃源 设备在正常运行和本义件规定的一些常规预期条件下应： a) 不能产生操作电弧或火花，除非按第7～10章所述的方法之一来防止其点燃周围的爆炸性环境； b)不能产生超过设备温度组别所对应的最高表面温度，除非按第7～10章所述的方法之一来防止表面温度或最热点的温度点燃周围的爆炸性环境，或者按第5章的规定证明是安全的。 4.3 设备要求 在正常运行中，有能力点燃周围环境的电弧、火花或热表面的设备或元件应采用下列一种或多种方法防止点燃(这些方法提供设备保护级别Gc)： a)非点燃元件(见第7章)； b)气密装置(见第8章)； c)密封装置(见第9章)； d)限制呼吸外壳(见第10章)。 5最高表面温度 应按照GB/T 3836.1确定最高表面温度的要求来确定最高表面温度。考虑的表面应是设备的外表面，也包括爆炸性气体环境有可能进入的非点燃元件的内部部件的表面。 注：这可能是位于“cc”级设备内部的“nC”元件的外表面。 6对电气设备的规定 6.1 通则 “n”型保护电气设备应符合本文件的要求和GB/T 3836.1适用部分的要求。 6.2 对地或机架绝缘的电气强度 如果设备中的电路不直接连接到设备机架上，或者在设备运行时不连接到机架上，则所用的绝缘或间距应能承受下列试验： a) 电气设备各部件的有关工业标准规定的试验。或 b)如果上述试验要求不存在，至少试验电压应按下列1)或2)要求，历时至少1 min不击穿。 1) 对于设备供电电压峰值不超过90 V或设备内部峰值电压不超过90 V的电气设备，试验电压的有效值为500 V(相对误差0％～5％)； 2) 对于其他电气设备，或设备内部电压峰值超过90 V，试验电压的有效值为2 U+1 000 V(相对误差0％～5％)或有效值1 500 V(相对误差0％～5％)，取二者之中较大值。 允许用直流试验电压代替规定的交流试验电压，对于绝缘绕组应为规定的交流试验电压有效值的170％，或者对于在绝缘介质中的电气间隙或爬电距离，应为规定的交流试验电压有效值的140％。 注：U是额定供电电压或者设备内部出现的最高电压中的较高值。 对于具有电隔离部件的设备，应在适当的电压下对各部件分别施加试验电压。 7非点燃元件的要求 7.1 型式试验 非点燃元件应进行11.1规定的型式试验。 7.2 电路限制 非点燃元件的最大额定值应限制在254 V和16 A交流有效值或直流。 注：非点燃元件触头的布置熄灭了初始火焰，因此不会点燃外部的爆炸性环境。非点燃元件限定用于与元件在试验时构成的电路或危险更小的电路具有相同电气特性值的电路中，例如电压、电流、电感、电容、冲击电流或过载条件。 8气密装置的要求 气密装置是由金属与金属或玻璃熔合而成的，符合密封装置的要求，不需要试验。 外壳应能承受正常的操作和组装作业而不损坏密封。 9密封装置的要求 9.1非金属材料 当密封装置不构成防爆设备外壳的一部分时，应按照11.2进行试验。当设备由一个独立的腔体和基座密封在一起时，腔体和基座不认为是密封的一部分。 按照GB/T 3836.1的要求，资料应包括密封装置制造商提供的数据表或者声明，以证明用于密封的材料满足将要承受的工作温度范围。用于密封的材料连续运行温度(COT)范围，下限应低于或等于最低工作温度并且上限比最高工作温度至少高10 K。该数据表或者声明，可以是密封或浇封材料，也可以是整个密封装置。当密封装置构成防爆设备外壳的一部分或全部时，GB/T 3836.1的要求适用。 9.2 开启 密封装置的结构在正常运行时应不能开启。 9.3 内部空间 密封装置的内部净容积应不超过100 cm3，并且必要时应设置外部连接件，例如引出线或外接端子。 9.4 操作 外壳应能承受正常的操作和组装作业而不损坏。 9.5衬垫和密封 衬垫和密封，包括灌封密封，安装位置应能使其在正常运行条件下不受机械损伤，并能在装置的预期寿命期间保持密封性能。 9.6型式试验 应进行11.2规定的型式试验。 10 限制呼吸外壳的要求 10.1 通则 限制呼吸设备应限制耗散功率，使测定的外部温度不超过GB/T 3836.1规定的最高表面温度。 限制呼吸外壳仅应以完整的设备来进行评价，包括全部配件和附件。 或者设备应配有引入装置，或者在“nR”设备的说明书中明确引入装置的选择信息。 10.2 结构要求 10.2.1 设备类型 10.2.1.1 装有普通火花装置的设备 装有普通电弧或火花装置的限制呼吸设备，或者有频繁温度循环的热表面的设备，应限制耗散功率，使在正常运行时外壳外部测得的温度不会高于环境温度20 K。