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GB/T 16935.5-2008 English PDF (GBT16935.5-2008)

GB/T 16935.5-2008 English PDF (GBT16935.5-2008)

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GB/T 16935.5-2008: Insulation coordination for equipment within low-voltage systems -- Part 5: Comprehensive method for determining clearances and creepage distances equal to or less than 2mm

GB/T 16935.5-2008
Insulation coordination for equipment within low-voltage systems. Part 5. Comprehensive method for determining clearances and creepage distances equal to or less than 2mm ICS 29.120
National Standards of People's Republic of China
GB/T 16935.5-2008/IEC 60664-5..2007
Low voltage system equipment with the insulation
Clearance and creepage distance determination method
(IEC 60664-5..2007, IDT)
2008-07-16 released
2009-04-01 implementation
General Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China China National Standardization Administration released
Preface Ⅰ
Introduction Ⅱ
1 Scope and purpose 1
2 Normative references 1
3 Terms and definitions 2
4 Basic rules for determining clearances and creepage distances 2
4.1 Introduction 2
4.2 The basic principle 2
4.3 voltage and its rating 3
4.4 Frequency 4
4.5 withstand voltage time 4
4.6 Pollution 4
4.7 Equipment to provide information 5
4.8 Insulation material 5
5 Requirements and rules for sizing 6
5.1 Overview 6
5.2 Determination of clearance 6
5.3 Determination of creepage distance 9
5.4 solid insulation design requirements 13
6 Test and Measurement 15
6.1 Test 15
Appendix A (informative) to determine the minimum size to maintain insulation resistance 21 Appendix B (Normative) Water absorption test 23
Appendix C (informative) Block diagram to determine the size 26
Appendix D (Informative) Creepage withstand withstand test under wet conditions 29 References 30
GB/T 16935.5-2008/IEC 60664-5..2007
GB/T 16935 "Low-voltage system equipment with insulation" is divided into 5 parts. --- Part 1. Principles, requirements and tests;
--- Part 2. Application Guide;
--- Part 3. The use of coating, sealing and molding anti-fouling protection; --- Part 4. high frequency voltage stress considerations;
--- Part 5. Determination of clearances and creepage distances not exceeding 2mm. This section GB/T 16935 Part 5.
This section identical with IEC 60664-5..2007 "Insulation coordination of equipment within low-voltage systems Part 5. Electrical no more than 2mm Clearance and creepage distance determination method "(in English).
For ease of use, this section made the following editorial changes.
a) delete the preface to international standards;
b) Chapter 2, "Normative references," supplemented reference to the GB/T 17045-2006, GB/T 17627.1-1998, GB/T 17627.2-1998, IEC 60068, IEC 60364-5-51..2005, IEC 60664-4..1997 (cited in the article cited use).
This part of the Appendix B is a normative appendix, Appendix A, Appendix C, Appendix D is an informative annex. This part is proposed by China Electrical Equipment Industry Association. This part of the National Standardization Technical Committee of low-voltage electrical (SAC/TC189) centralized. This section is responsible for drafting unit. Shanghai Electric Institute of Science (Group) Co., Ltd.. Participated in the drafting of this section. Schneider Electric (China) Investment Co., Ltd.. The main drafters of this section. Huang Jingye, Liu Jinyan, Wu Qingyun. Participate drafters of this section. Liu Zhenzhong.
GB/T 16935.5-2008/IEC 60664-5..2007
This section specifies the humidity on the creepage distance humidity level. This section describes the following guidelines for determining sizes to consider together. --- Fill level 2 and 3 under Table 1, Part F The values specified in 2 are more accurate than the new minimum of 2 mm or less clearance;
--- Part 1 of Table 1 printed circuit boards and similar structural parts at pollution level 3. 4 provisions of the smaller creepage distance; --- Avoid the occurrence of flashover on the insulating surface minimum creepage distance requirements, the value of the material according to the water absorption characteristics; --- In humid conditions to ensure adequate insulation resistance of the minimum creepage distance requirements. Note. Table A. 2 gives information on the determination of the size of the creepage distance so that the root mean square value of the voltage does not exceed 10000V and the corresponding creepage distance does not exceed 250mm, to maintain adequate insulation resistance.
The information in this section is based on published research [1,2] 1). The following research details give relevant background information.
--- Research conducted on the test sample, the test pattern with the circuit pattern spacing from 0.16mm ~ 6.3mm printed circuit board the same Process for production;
--- Test using 10 different materials, the manufacturing process on the surface of the material, such as molding, processing, etc., not as the research item Part of purpose
--- Test sample placed in different regions, such as urban, rural, industrial, desert and coastal areas; --- Specimen exposed to voltage stress on a regular basis, the relevant data has accumulated for a long period of time. Appendix B specifies the water absorption test method for distributing unclassified insulating materials to the relevant water absorption group. When using different materials Test Methods For further empirical data, this appendix will be revised. 1) The numbers in square brackets refer to the references.
GB/T 16935.5-2008/IEC 60664-5..2007
Low voltage system equipment with the insulation
Clearance and creepage distance determination method
1 Scope and purpose
GB/T 16935 provisions of this part of printed circuit boards and similar structures of not more than 2mm clearance and creepage distances Dimensional determination method in which the clearances and creepage distances are the same and are all along the surface of the solid insulation as in 6.2 in Part 1 2) The described path (examples 1, 5 and 11).
2) Part 1 refers to GB/T 16935.1.
This method of dimensioning is more accurate than the method specified in Part 1. However, Part 1 is applicable if exact dimensions are not required. This section can only be used as a whole, does not allow the selection of one or a few uses of this section, they are not allowed to replace the first Part of the corresponding terms to use. And this part can only be used in conjunction with Part 1. When using this section to determine the dimensions of clearance and creepage distances, the full clause shall supersede the corresponding clause given in Part 1. Part 1 applies to clearances and creepage distances greater than 2 mm and to general solid insulation. Note 1. The limit of 2 mm or less applies to basic or supplementary insulation, and the total distance of reinforced or double insulation may be greater than 2 mm. This section is based on the following criteria to determine the size.
--- Minimal clearance independent of the micro-environment (see Table 2); --- For pollution levels 1, 2 and 3 to avoid the minimum creepage distance due to tracking (see Table 4); --- Avoid creepage insulation surface flashover minimum creepage distance (see Table 5). Note 2. See Table A for minimum creepage distances for adequate insulation resistance. 2. Note 3. This section does not apply to the micro-environmental conditions than the pollution level 3 or humidity level 3 poor. This standard specifies a test method for the distribution of unclassified insulating materials to the relevant water absorption group. 2 Normative references
The terms of the following documents through the GB/T 16935 of this part of the reference and become the provisions of this section. For dated references, All subsequent amendments (not including errata content) or revisions do not apply to this section, however, to encourage the agreement reached under this section The parties study whether the latest versions of these documents are available. For undated references, the latest version applies to this section. Part 1, Chapter 2 and the following apply.
GB/T 4798.3-2007 Environmental conditions for the application of electrical and electronic products Part 3. a fixed place with climate protection (IEC 60721-3-3..2002, MOD)
GB/T 4798.7-2007 Environmental conditions for the application of electric and electronic products Part 7. Portable and non-fixed use (IEC 60721-3- 7..2002, MOD)
GB/T 4798.9-1997 Environmental conditions for the application of electrical and electronic products Micro-climate within the product (idt IEC 60721-3-9..1993) GB/T 16895.18-2002 Electrical installations in buildings - Part 5. Selection and installation of electrical equipment Chapter 51. General regulations Then (IEC 60364-5-51..1997, IDT)
Insulation coordination of equipment in low-voltage systems - Part 1. Principles, requirements and tests (IEC 60664-1. 2007, IDT)
GB/T 17045-2006 Shock protection devices and equipment common part (IEC 61140..2001, IDT) GB/T 17627.1-1998 high voltage test techniques for low voltage electrical equipment - Part 1. Definitions and test requirements (eqv IEC GB/T 16935.5-2008/IEC 60664-5..2007
GB/T 17627.2-1998 high voltage test techniques for low voltage electrical equipment Part II. Measurement systems and test equipment (Eqv IEC 61180-2..1994)
IEC 60068 Environmental Testing
IEC 60664-4..1997 Insulation coordination of equipment in low voltage systems - Part 4. Considerations for high frequency voltage stress 3 Terms and definitions
In addition to GB/T 16935.1-2008 provisions, the following terms and definitions apply. 3.1
The ability of insulating materials to adsorb their surface moisture.
The relative humidity value when the creepage withstand voltage of the creepage distance (its value is measured at 70% relative humidity) drops to 95%. 4 to determine the basic principles of clearance and creepage distance
4.1 Introduction
The first publication on the insulation coordination of equipment in low-voltage systems is published by IEC 60664, It only covers clearances and numbers According to the breakdown voltage from the basic data. Then, published in 1981 by IEC 60664A, the publication deals with creepage distances and data from Many years of practical experience and printed circuit board test obtained. In.1992, the above publication was merged and published IEC 60664-1 (Part 1) Points), but the revised version did not change the basic data.
4.2 The basic principle
Insulation coordination refers to the selection of the electrical insulation characteristics of a device based on the use of the device and its surrounding environment. Insulation coordination can only be achieved if the design of the equipment is based on the stresses experienced during its expected lifetime. Except as provided in the following clauses, 4.2 in Part 1 applies.
4.2.5 on the temporary over-voltage insulation coordination
Insulation coordination for temporary overvoltages The temporary overvoltages specified in 442 of IEC 60364-4-44 (see of this part) are basis.
Note. Current surge protectors (SPDs) do not adequately absorb the energy generated by temporary overvoltages. 4.2.6 on the environmental conditions of the insulation coordination
Insulation should be considered micro-environmental conditions. This depends mainly on the macro environment in which the device is located. In many cases, microenvironments and macros The concept of environment is the same. However, the micro-environment may be better or worse than the macro environment. For example, the enclosure, heating, ventilation or dust may be shadowed Micro-environment.
Note. Shell protection in accordance with the degree of protection GB 4208 [3] can improve the micro-environmental humidity. The main environmental parameters are as follows.
--- For the electrical clearance.
● pressure;
● temperature, if the range of changes;
--- For the creepage distance.
● pressure;
● pollution;
● relative humidity;
● condensation;
GB/T 16935.5-2008/IEC 60664-5..2007
--- For solid insulation.
● temperature;
● Relative humidity.
4.3 Voltage and its rating
4.3.1 Overview
Part 1 of 4.3.1 applies.
4.3.2 long-term role in the determination of voltage Overview
Part 1 of applies. determine the basic insulation voltage Equipment powered directly from the low-voltage network
Table 1 in Part 1 3a and Table F 3b has been the nominal voltage of low-voltage power grid into a rationalization voltage, this voltage can be used as a Set the minimum creepage distance voltage can also be used to select the rated insulation voltage equipment. The electrical equipment can have several rated voltages so that it can be used in low voltage networks with different nominal voltages. Such equipment voltages should be chosen The highest rated voltage.
Each product standard technical committee should consider how to choose the voltage. --- Based on "line to line" voltage; or
--- Based on "line to neutral" voltage.
In the latter case, the technical committee of the product standard should specify how the user should be informed that the device can only be used in a neutral earthing system. Systems, equipment and internal circuits not directly fed by the low-voltage network Part 1 of applies. to determine the function of insulation voltage
Part 1 of applies.
4.3.3 Determination of the rated impulse voltage Overview
Part 1 applies. Overvoltage category Overview
Part 1 of applies. Equipment powered directly by the grid
Part 1 of applies. Systems and equipment not directly powered by a low-voltage network Part 1 of applies. Equipment rated impulse voltage of choice
Part 1 applies. Insulation coordination of impulse voltage inside the equipment Components or circuits internal to the equipment that are significantly affected by external transient overvoltages Part 1 applies. Components or circuits inside the equipment with specific transient overvoltage protection Due to the external transient over-voltage has little effect, the basic insulation requirements of these components, the impact of withstand voltage and the rated impact of equipment The voltage has nothing to do with the actual conditions of the component or circuit, it is recommended that the preferred value of the impulse voltage listed in 4.2.3, part 1, Quasi-chemical, other cases, can be obtained using the insert value method of Table 2 of this section. GB/T 16935.5-2008/IEC 60664-5..2007 Operation overvoltage generated by the equipment
Part 1 of applies. interface requirements
Part 1 applies.
4.3.4 Determination of reproduction peak voltage
Part 1 of 4.3.4 applies.
4.3.5 temporary over-voltage determination Overview
Part 1 of applies. fault voltage
Part 1 of applies. temporary over-voltage caused by stress
The magnitude and duration of the temporary overvoltage caused by the low voltage equipment due to the earth fault of the high voltage system is given in 4.4 Frequency
Part 1 4.4 applicable.
4.5 to withstand the role of voltage time
Part 1 4.5 is applicable.
4.6 pollution
4.6.1 Overview
Contamination not only attenuates the insulation associated with the long-term rms voltage stress that causes tracking, but also weakens the peak voltage and water absorption Related insulation. Contamination caused by short-range impact resistance endurance decreased, the result may flash across the insulation surface flashover. The effect of humidity on the insulating surface is determined by the moisture level specified in 4.6.4. The impact of water absorption on the insulating surface is defined in 4.8.6 The water absorption group OK.
4.6.2 Micro-environmental pollution levels
Section 1 4.6.2 applies.
4.6.3 conductive pollution conditions
Not applicable.
4.6.4 Humidity level
In order to determine the creepage distance or minimum insulation resistance associated with the flashover on the insulating surface, the micro-environment humidity specifies the following three grade.
--- Humidity Level 1 (HL1). The relative humidity of the insulating surface will never reach the level of condensation, so the flashover is not affected by humidity influences;
--- Humidity Level 2 (HL2). Occasionally, the relative humidity of the insulating surface in the micro-environment changes will produce condensation, so the flashover by Influence of humidity
--- Humidity Level 3 (HL3). The relative humidity of the insulation surface often produce condensation, so the flashover is seriously affected by humidity. 4.6.5 Humidity levels and the relationship between the macro environment Macroscopic environmental conditions in GB/T 16895.18-2002, GB/T 4798.3-2007, GB/T 4798.7-2007 and GB/T 4798.9- 1997 made.
Note. Different climate classification is used in GB/T 4798.9-1997.
Table 1 shows the relationship between the micro-environmental humidity level and the specified macro-environmental classification. GB/T 16935.5-2008/IEC 60664-5..2007
Table 1 the relationship between the humidity level and the macro environment level Criteria for setting climate classification (macro environment) Climatic classification Humidity level GB/T 4798.9-1997 Y2 Y3 Y4
GB/T 4798.3-2007 3K1 3K3 3K6
GB/T 4798.7-2007 7K1 7K3
GB/T 16895.18-2002
= (-) (-) → HL1
(+) = (-) → HL2
(+) (+) = → HL3
= The same micro-environment and macro-environment humidity;
(-) Micro-environment humidity is lower than macro-environment humidity; (+) Micro-environment humidity is higher than macro-environment humidity. 4.7 Equipment provided information
In Part 1, 4.7 applies.
4.8 Insulation material
4.8.1 Overview
Insulation materials should be divided into different groups according to their CTI values. Each product standard technical committee should consider the electrical strength characteristics of insulation, thermal, mechanical, chemical and water absorption characteristics. About solid absolutely Marginal requirements, 5.4 of this section applies.
4.8.2 Compared to the tracking index (CTI) Insulating material performance under flicker in Part 1 applies. CTI values for the classification of insulating materials
In Part 1, applies. Material groups
Part 1 applies. compared to the tracking index (CTI) test
In Part 1, applies. Electroless materials
For glass, ceramic or other inorganic insulating material, does not occur tracking, creepage distances need not be greater than the corresponding insulation The required electrical clearance. The dimensions used in Table 2 for non-uniform electric field conditions apply. 4.8.3 Electrical Strength Characteristics
Part 1 applies to 4.8.2.
4.8.4 Thermal Characteristics
4.8.3 Part 1 applies.
4.8.5 Mechanical and Chemical Properties
Part 1 4.8.4 applies.
4.8.6 Water absorption characteristics
Water absorption is a surface phenomenon associated with the properties of insulating materials. In view of the impact of water absorption on the withstand voltage capability, according to the attached Record B test procedures, insulation materials a...

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