GB/T 16935.3-2016Insulation coordination for equipment within low-voltage systems -- Part 3: Use of coating, potting or moulding for protection against pollution (English PDF)

Foreword

GB/T 16935 "Insulation coordination for equipment within low-voltage systems" is

expected to consist of the following parts.

- Part 1.Principles, requirements and tests;

- Part 2-1.Application guide. Explanation of the application of the GB/T 16935 series,

dimensioning examples and dielectric testing;

- Part 2-2.Interface considerations - Application guide;

- Part 3.Use of coating, potting or moulding for protection against pollution;

- Part 4.Consideration of high-frequency voltage stress;

- Part 5.Comprehensive method for determining clearances and creepage

distances equal to or less than 2 mm.

This Part is Part 3 of GB/T 16935.

This Part is drafted in accordance with the rules given GB/T 1.1-2009.

This Part replaces GB/T 16935.3-2005 "Insulation coordination for equipment within

low-voltage systems - Part 3.Use of coating, potting or moulding for protection against

pollution". Compared with GB/T 16935.3-2005, main technical differences are as

follows.

- In 4.4 "Dimensioning procedures", it is clearly state that the specified values of

minimum spacing of type 2 protection may also be applied to functional insulation;

- In 5.5 "Scratch resistance test", modify the content of the first paragraph and add

a note, and detail the description for the specific parts of scratch resistance test;

- REPLACE 5.6 "Visual examination", 5.8.3 "Insulation resistance between

conductors", 5.8.4 "AC withstand voltage test", 5.9.1 "Resistance to soldering

heat", 5.9.2 "Flammability" and the reference standard IEC 60326-2 "Printed

boards; Part 2.test methods" in Annex A WITH IEC 61189-3 "Test methods for

electrical materials, printed boards and other interconnection structures and

assemblies. Part 3.Test methods for interconnection structures (printed boards)",

and UPDATE the test basis and method;

- In 5.9.3 "Solvent resistance" and Annex A, modify the solvent resistance

requirement from "According to 8.5 in IEC 60326-2, use methylene chloride" to

"Solvent as agreed between purchaser and supplier".

This Part uses the translation method to identically adopt IEC 60664-3.2010 (2.1

edition) "Insulation coordination for equipment within low-voltage systems - Part 3.Use

of coating, potting or moulding for protection against pollution".

This Part shall be used together with GB/T 16935.1-2008 "Insulation coordination for

equipment within low-voltage systems - Part 1.Principles, requirements and tests"

(IEC 60664-1.2007, IDT).

China's national document that correspond in a consistent manner to the International

document normatively referenced in this Part is as follows.

- GB/T 4677-2002 Test methods of printed boards (eqv IEC 60326-2.1990).

This Part has made the following editorial modification.

- "93" in 5.7.4.1 and 5.8.1 is wrong, which is modified to "93 % ± 3 %".

This Part is proposed by China Electrical Equipment Industry Association.

This Part is under the jurisdiction of National Technical Committee on Low Voltage

Equipment Insulation Coordination of Standardization Administration of China

(SAC/TC 417).

Responsible drafting organization of this Part. Shanghai Electric Apparatus Research

Institute.

Participating drafting organizations of this Part. Delixi Electric Co., Ltd., Changshu

Switch Manufacturing Co., Ltd. (formerly Changshu Switch Factory).

Main drafters of this Part. Huang Jingye, Bao Ge, Wu Qingyun, Zhang Lili, Lin Chuan,

Zhou Jianxing.

The historical edition of the standard replaced by this Part is.

- GB/T 16935.3-2005.

1 Scope

This Part of GB/T 16935 applies to assemblies protected against pollution by the use

of coating, potting or moulding, thus allowing a reduction of clearance and creepage

distances as described in Part 1 or Part 5.

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 2423.1-2008 Environmental testing - Part 2.Test methods - Tests A. Cold (IEC

60068-2-1.2007, IDT)

3 Definitions

For the purposes of this document, the definitions given in GB/T 16935.1-2008 as well

as the following definitions apply.

Any kind of measure which reduces the influence of the environment.

4 Design requirements

For type 1 protection, the dimensioning requirements of 5.1 and 5.2 of Part 1 or Part 5

apply.

For type 2 protection, the spacing between the conductors before the protection is

applied shall not be less than the values as specified in Table 1.T