Please refer to this standard for details. GB 16895.2-1997 Electrical installations in buildings Part 4: Safety protection Chapter 42: Thermal effect protection GB16895.2-1997 Standard download decompression password: www.bzxz.net

GB 16895.2—1997
This standard is an expansion standard of GB16895 "Electrical installations of buildings" and is equivalent to IFC364-4-42:1980 "Electrical installations of buildings Part 4: Safety protection Chapter 42: Protection against thermal effects". GB16895 is divided into the following seven parts under the general title of "Electrical installations of buildings": Part 1: Scope, purpose and basic principles Part 2: Definitions Part 3: Evaluation of general characteristics Part 1: Safety protection Part 5: Selection and installation of electrical equipment Part 6: Inspection Part 7: Requirements for special installations or locations Each part includes the following independent chapters. This standard is Chapter 42 in Part 4 "Safety protection". This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Electrical Installations in Buildings. The drafting unit of this standard is China Machinery and China Electric Design Institute. The main drafters of this standard are He Xiangkun, Fan Gending and Gu Xin. GE16895.2-1997
IEC Foreword
1) [EC's final resolutions or agreements on technical issues are formulated by technical committees participated by those national committees that are particularly concerned with these issues, and express international consensus on the subjects involved as much as possible. 2) These resolutions or agreements are in the form of recommendations for international use and are accepted by the various national committees in this sense. 3) In order to promote international consensus, IEC expresses the desire that the national committees adopt the texts recommended by TEC in their respective national regulations when national conditions permit. Any differences between the text recommended by the TEC and the corresponding national regulations should be clearly pointed out in the national regulations.
IEC Foreword
This standard is the draft of this standard prepared by IFC Technical Committee No. 64 (Electrical Installations in Buildings) after discussion at the Moscow meeting in 1977 and the Sydney meeting in 1979. According to the results of the latter meeting, the draft, namely Document No. 64 (Central Office) 87, was submitted to the national committees for voting in December 1979 in accordance with the "six-month method": the national committees of the following countries voted clearly in favor: Australia
CanadabZxz.net
New Zealand
+ refers to the former Soviet Union.
Roman Mud Industry
South Africa (Republic)
Soviet Union"
National Standard of the People's Republic of China
Electrical installations of buiidingsPart 4: Protection for safetyChapter 42: Protection against thermal effects42 Protection against thermal effects
GB 16895.2--1997
ideIEC364-4-42:1980
Note: "Fire\ This name test and its related tests are considered by the International Organization for Standardization (IS) and IEC in joint consideration: This name is used in this chapter: 421 General
People, fixed equipment and fixed materials near electrical equipment should be protected to prevent the harmful effects of heat accumulation or heat radiation generated by the electrical equipment, in particular the following effects:
. Burning or aging of materials
- Danger of purchase:
- Impairment of the safety functions of the installed equipment
Note: Overcurrent protection is in IEC 364-4-43 Regulations in the standard. 422 Fire protection || tt || 422.1 Electrical equipment should not cause fire hazards to adjacent materials. In addition to complying with the requirements of GB16895 "Electrical Installations in Buildings": The manufacturer's installation instructions should also be followed. 422.2 When the surface temperature of fixed equipment may cause fire hazards to adjacent materials, the equipment should: - be installed on or in materials that can withstand such temperatures and have low thermal conductivity; or - be separated from building components by materials that can withstand such temperatures and have low thermal conductivity; or - be installed at a sufficient distance from any material that may cause harmful thermal effects at such temperatures to allow the heat to spread safely. At this time, any supporting parts should have low thermal conductivity. 422.3 For permanently connected equipment that will produce arcs or sparks during normal operation, the equipment should: - be completely surrounded by arc-resistant materials. or use arc-resistant materials to isolate the equipment from building components where the arc may introduce harmful thermal effects, or install it at a sufficient distance from such building components where the arc may cause harmful thermal effects, so that the arc heat can be safely dissipated. The arc-resistant materials used for this protection measure should be non-combustible, have low thermal conductivity, and have sufficient thickness to ensure mechanical stability.
422.4 Fixed equipment that may cause heat focusing or heat collection should be kept at a sufficient distance from any fixed object or building component so that the object or component will not be subjected to dangerous temperatures under normal circumstances. 422.5 When the equipment in the environment contains more than a certain amount of flammable liquid, precautions should be taken to prevent the burning liquid and the National Technical Supervision Bureau. Approved on June 28, 1997 and implemented on September 1, 1998
GB 16895.2—1997
When the liquid burns, the flame, smoke or toxic gas will spread to other parts of the building. Note
1 The following are some of the precautions: t
Set up a drainage pit to collect the leaked liquid and ensure that the fire is extinguished when the fire is strong, or - install the equipment in a small space with sufficient fire resistance and set up a sill or take other measures to prevent the burning liquid from spreading to other parts of the building. This is related to the small room. There should be a separate ventilation between the room and the outside. 2 The lower limit of the recognized constant is 251..
3 When it is less than 25 L, the arrangement can prevent the leakage of the body: 4 It is best to cut off the power supply in the event of a fire.
422.6 The material of the outer sheath around the electrical equipment used in the installation should be able to withstand the maximum temperature that the electrical equipment may produce. Combustible materials are not suitable for use in such outer coverings unless measures are taken to prevent ignition, such as covering with non-combustible or low thermal conductivity materials.
423 Burn protection
The temperature of accessible parts of electrical equipment within the scope of use shall not reach a level that may cause burns to personnel, and shall comply with the corresponding temperature limits listed in Table 12A. All parts of the equipment, in normal operation, whose temperatures may exceed the limits listed in Table 42A, even for a short period of time, should be protected to prevent any accidental contact. In order to prevent burns, some equipment adopts the Chinese standard or IEC standard of the TFC standard, which has specified the temperature limits of exposed surfaces. For equipment that complies with these regulations, the values ​​in Table 42A are not applicable. Table 42A Temperature limits of accessible parts of equipment within the range of the intermediate arm during normal operation
Accessible parts
Parts prohibited from operation
Parts that are not easily touched
Parts not required to be touched during normal operation
424 Overheating protection
424.1 Forced air heating system
Accessible surface materials
Metal
Non-metallic
Metal
Metal
Non-metallic
Maximum temperature
424.1.1 The heating elements of the forced air heating system, except the central heat accumulator, shall be inoperable before the specified air flow is established and shall stop working when the air flow stops. In addition, there shall be two independent temperature limiters to prevent the temperature in the ventilation duct from exceeding the permissible value. 424.1.2 The base and outer covering of the heating element shall be of non-combustible material. 424.2 Equipment producing hot water or steam
All equipment producing dust-producing hot water or steam shall be designed or installed to protect the equipment from overheating under various operating conditions, unless the equipment fully complies with the provisions of the Chinese standard adopting the corresponding IFC standard or the corresponding IEC standard, otherwise it shall be protected by an appropriate non-automatic reset element, the operation of which is independent of the overflow regulator. If such equipment is equipped with a safety valve, a water suppressor shall also be provided.
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