Detail of GB/T 16895.2-2017

Introduction of GB/T 16895.2-2017

GB/T 16895 Low-voltage electrical installations is divided into five parts, and each part is divided into several sub-parts: ——Part 1: Fundamental principles, assessment of general characteristics, definition; ——Part 4: Protection for safety; ——Part 5: Selection and erection of electrical equipment; ——Part 6: Verification; ——Part 7: Requirements for special installations or locations. This part is sub-part 42 of GB/T 16895 Low-voltage electrical installations—Part 4: Protection for safety. This part is developed in accordance with the rules given in GB/T 1.1-2009. This part replaces GB/T 16895.2-2005 Electrical installations of buildings—Part 4-42: Protection for safety—Protection against thermal effects, and the following main technical changes have been made with respect to GB/T 16895.2-2005: ——The scope now includes protection against all thermal effects and flames in case of a fire hazard being propagated from electrical installations to other fire compartments segregated by barriers which are in the vicinity. ——Requirements associated with escape routes for evacuation in an emergency have been expanded/modified; ——Requirements associated with the nature of processed or stored materials have been expanded/modified; ——Requirements associated with combustible constructional materials have been expanded/modified; ——Requirements associated with fire propagating structures have been expanded/modified; ——New requirements for the selection and erection of installations in locations which might endanger precious goods have been added; ——Protection against overheating now includes space heating appliances. This part, by means of translation, is identical to IEC 60364-4-42: 2010 Low-voltage electrical installations—Part 4-42: Protection for safety—Protection against thermal effects. The Chinese documents identical to the normative international documents given in this part are as follows: ——GB 7000.17-2003 Safety requirements for luminaires with limited surface temperatures (IEC 60598-2-24: 1997, IDT) ——GB/T 18380 (all parts) Tests on electric and optical fiber cables under fire conditions [IEC 60332 (all parts)] ——GB/T 19215 (all parts) Cable trunking and ducting systems for electrical installations [IEC 61084 (all parts)] ——GB/T 19215 (all parts) Cable trunking and ducting systems for electrical installations [IEC 61084 (all parts)] ——GB/T 20041 (all parts) Conduit systems for cable management [IEC 61386 (all parts)] ——GB/T 21762—2008 Cable management—Cable tray systems and cable ladder systems (IEC 61537: 2006, IDT) This part is identical to IEC 60364-4-42: 2010 in clause and article numbers and technical contents, with only the following editorial changes: Annex A has been deleted in this part as it is the national note of other countries applying this standard and is irrelevant to China. This standard was proposed by and is under the jurisdiction of SAC/TC 205 National Technical Committee on Electrical Installations of Buildings of Standardization Administration of China. The previous editions of this standard are as follows: ——GB/T 16895.2-1997, GB 16895.2-2005, GB/T 16895.2-2005. Low-voltage electrical installations— Part 4-42: Protection for safety—Protection against thermal effects 420.1 Scope This part of GB/T 16895 applies to electrical installations with regard to measures for the protection of persons, livestock and property against ——thermal effects, combustion or degradation of materials, and risk of burns caused by electrical equipment, ——flames in case of a fire hazard being propagated from electrical installations to other fire compartments segregated by barriers which are in the vicinity, and the impairment of the safe functioning of electrical equipment including safety services. Note: Protection against overcurrent is dealt with in IEC 60364-4-43. 420.2 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 16895.18-2010 Electrical installations of buildings—Part 5-51: Selection and erection of electrical equipment—Common rules (IEC 60364-5-51: 2005, IDT) GB/T 16895.21-2011 Low-voltage electrical installations—Part 4-41: Protection for safety—Protection against electric shock (IEC 60364-4-41:2005, IDT) IEC 60332 (all parts) Tests on electric and optical fibre cables under fire conditions IEC 60598-2-24 Luminaires Part 2-24: Particular requirements—Luminaires with limited surface temperatures IEC 61084 (all parts) Cable trunking and ducting systems for electrical installations IEC 61386 (all parts) Conduit systems for cable management IEC 61534 (all parts) Powertrack systems IEC 61537 Cable management—Cable tray systems and cable ladder systems 420.3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 420.3.1 combustible capable of burning 420.3.2 fire ——a process of combustion characterized by the emission of heat and effluent accompanied by smoke, and/or flame and/or glowing ——rapid combustion spreading uncontrolled in time and space 420.3.3 flammability ability of a material or product to burn with a flame under specified test conditions 420.3.4 ignitability measure of the ease with which a specimen can be ignited due to the influence of an external source, under specified test conditions 420.3.5 ignition initiation of combustion Note: For more information see IEC 60695-4. 420.3.6 non-flam propagating component component which is liable to ignite, as a result of an applied flame, but in which the flame does not propagate and which extinguishes itself within a limited time after the flame is removed [IEC 60050-442:1998, 442-01-12] 421 Protection against fire caused by electrical equipment 421.1 General requirements Persons, livestock and property shall be protected against damage or injury caused by heat or fire which may be generated or propagated in electrical installations by taking into account the requirements of this standard and the instructions of equipment manufacturers. The heat generated by electrical equipment shall not cause danger or harmful effects to adjacent fixed material or to material which may foreseeably be in proximity to such equipment. Electrical equipment shall not present a fire hazard to adjacent materials. Note: Damage, injury or ignition may be caused by effects such as ——heat accumulation, heat radiation, hot elements, ——reduction of the safe function of electrical equipment, e.g. protective devices such as protective switchgear, thermostats, temperature limiters, seals of cable penetrations and wiring systems, ——overcurrent, ——insulation faults and/or arcs causing interference, ——harmonic currents, ——lightning strikes, see the IEC 62305 series, ——overvoltage, see Clause 443 of GB/T 16895.10-2010, ——inappropriate selection or erection of equipment. Any relevant manufacturer’s erection instructions shall be taken into account in addition to the requirements of the GB/T 16895 series. 421.2 Where fixed equipment may attain surface temperatures which could cause a fire hazard to adjacent materials, the equipment shall either · be mounted on or within materials that will withstand such temperatures and are of low thermal conductance, or · be screened from elements of building construction by materials which will withstand such temperatures and are of low thermal conductance, or

Contents of GB/T 16895.2-2017

Foreword i 420.1 Scope 420.2 Normative references 420.3 Terms and definitions 421 Protection against fire caused by electrical equipment 422 Precautions where particular risks of fire exist 422.1 General 422.2 Conditions of evacuation in an emergency 422.3 Locations with risks of fire due to the nature of processed or stored materials 422.4 Locations with combustible constructional materials 422.5 Fire propagating structures 422.6 Selection and erection of installations in locations with endangering of irreplaceable goods 423 Protection against burns 424 Protection against overheating 424.1 Forced air heating systems 424.2 Appliances producing hot water or steam 424.3 Space heating appliances Bibliography