GB/T 3836.9-2021Explosive atmospheres - Part 9: Equipment protection by encapsulation 'm' (English PDF)

Foreword

This document was drafted in accordance with the rules in GB/T 1.1-2020 Directives

for Standardization - Part 1.Rules for the Structure and Drafting of Standardizing

Documents.

This document is Part 9 of GB/T 3836 Explosive Atmospheres. GB/T 3836 has

released 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 Liquid Immersion "o";

---Part 7.Equipment Protection by Powder Filling "q";

---Part 8.Equipment Protection by Type of Protection "n";

---Part 9.Equipment Protection by Encapsulation "m";

---Part 11.Material Characteristics for Gas and Vapor Classification - Test Methods

and Data;

---Part 12.Material Characteristics for Combustible Dusts - Test Methods;

---Part 13.Equipment Repair, Overhaul, Reclamation and Modification;

---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 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 document serves as a replacement of GB 3836.9-2014 Explosive Atmospheres -

Part 9.Equipment Protection by Type of Protection "m" and GB 12476.6-2010

Electrical Apparatus for Use in the Presence of Combustible Dust - Part 6.Protection

by Encapsulation "mD". This document focuses on GB 3836.9-2014 and integrates the

main content of GB 12476.6-2010.In comparison with GB 3836.9-2014, apart from

structural adjustments and editorial modifications, the main technical changes are as

follows.

---Additional requirements for protection level "mb" are added (see 4.2);

---The requirements for thermal conductivity are added to the specification (see

5.2);

---The option of determining reliable components and isolation compounds in a

fault is added (see 7.2);

---The dimensional drawing of compound thickness is modified (see 7.4.1; 7.4.1

of Version 2014);

---Standard options for multi-layer printed circuit boards with rigid through-

connections are added (see 7.4.3.1);

---Additional requirements for batteries are modified and added (see 7.8.3; 7.8.3

of Version 2014);

---The requirements for 2 protective devices with protection level "ma" are added

(see 7.9.2);

---The requirements for 2 thermal protective devices with protection level "mb" are

added (see 7.9.3);

---The restriction of two-thirds of the rated voltage of the resettable thermal

protective device with switching contacts is deleted (see 7.9.3 of Version 2014);

---The requirements for the determination of the maximum surface temperature of

protection level "Da" are added (see 8.2.2);

---The reference service temperature of the thermal endurance test is modified

(see 8.2.3.1; 8.2.3.1 of Version 2014);

---The option of type test of dielectric strength is added (see 8.2.4.1);

---An alternative method for the pressure test of equipment with protection level

"mb" is added (see 8.2.6);

---The requirement for the number of samples for sealing test with built-in

protective devices and the method of reducing samples are added (see 8.2.8);

---Different situations of routine dielectric strength test are added (see 9.2);

---The requirements for the dielectric strength test between the circuit and the

environment are added (see Appendix C).

This document adopts the re-drafting method in the modification and adoption of IEC

60079-18.2014 Explosive Atmospheres - Part 18.Equipment Protection by

Encapsulation "m".

The technical differences between this document and IEC 60079-18.2014, and the

causes for the differences are as follows.

---In terms of Normative References, this document makes certain adjustments

with technical differences, so as to adapt to the technical conditions of China.

The adjustments are intensively reflected in Chapter 2 "Normative References".

See the specific adjustments below.

 GB/T 1408.1, which equivalently adopts international standard, is used to

replace IEC 60243-1 (see 5.2);

 GB/T 3836.1, which modifies and adopts international standard, is used to

replace IEC 60079-0 (see Chapter 1);

 GB/T 3836.3, which modifies and adopts international standard, is used to

replace IEC 60079-7 (see 7.2.2);

 GB/T 3836.4, which modifies and adopts international standard, is used to

replace IEC 60079-11 (see 7.2.2);

 GB/T 3836.8, which modifies and adopts international standard, is used to

replace IEC 60079-15 (see 7.5.2);

 GB 3836.20, which modifies and adopts international standard, is used to

replace IEC 60079-26 (see 7.6.2);

 GB/T 3836.31, which modifies and adopts international standard, is used

to replace IEC 60079-31 (see 7.6.2);

 GB/T 7153, which equivalently adopts international standard, is used to

replace IEC 60738-1 (see 7.9.3);

 GB/T 9816.1, which modifies and adopts international standard, is used to

replace IEC 60691 (see 7.8.5);

 GB/T 14536.10, which equivalently adopts international standard, is used

to replace IEC 60730-2-9 (see 7.9.3);

 GB/T 17045, which equivalently adopts international standard, is used to

replace IEC 61140 (see 7.2.3);

 GB/T 19212.1, which modifies and adopts international standard, is used

to replace IEC 61558-1 (see 7.2.3);

 GB/T 19212.7, which equivalently adopts international standard, is used to

replace IEC 61558-2-6 (see 7.2.3);

 GB/T 9364 (all parts) is used to replace IEC 60127 (all parts) (see 7.8.5).

The degree of consistency between the various parts of the two standards

is as follows.

 GB/T 9364.1-2015 Miniature Fuses - Part 1.Definitions for Miniature

Fuses and General Requirement for Miniature Fuse-links (IEC 60127-

1.2006, MOD);

 GB/T 9364.2-2018 Miniature Fuses - Part 2.Cartridge Fuse-links (IEC

60127-2.2014, MOD);

 GB/T 9364.3-2018 Miniature Fuses - Part 3.Sub-miniature Fuse-links

(IEC 60127-3.2015, MOD);

 GB/T 9364.4-2016 Small Fuses - Part 4.Universal Module Fuse-links

(UMF) - Perforated and Surface Mount (IEC 60127-4.2012, MOD);

 GB/T 9364.5-2011 Miniature Fuses - Part 5.Guidelines for Quality

Assessment of Miniature Fuse-links (IEC 60127-5.1988, IDT);

 GB/T 9364.6-2001 Miniature Fuses - Part 6.Fuse-holders for

Miniature Cartridge Fuse-links (IEC 60127-6.1994, IDT);

 GB/T 9364.7-2016 Small Fuses - Part 7.Small-sized Fuse-links for

Special Applications (IEC 60127-7.2013, MOD);

 GB/T 9364.10-2013 Miniature Fuses - Part 10.User Guide for

Miniature Fuses (IEC 60127-10.2001, MOD).

---e) is deleted from Chapter 10 Marking, because this requirement is already

included in GB/T 3836.1-2021.

This document makes the following editorial modifications.

---In order to be consistent with the existing standard series, the title of this

document is modified into Explosive Atmospheres - Part 9.Equipment

Protection by Encapsulation "m";

---The FOOTNOTE and NOTE in Table 1 are incorporated;

---The Amendment of IEC 60079-18.2014/AMD1.2017 and the Corrigendum of

IEC 60079-18.2014/COR1.2018 are incorporated; the outer margin of the

involved clauses is marked with a vertical double line ();

---The Bibliography is modified.

Please be noted that certain content of this document may involve patents. The

institution issuing this document does not undertake the responsibility of identifying

these patents.

This document was proposed by China Electrical Equipment Industry Association.

This document shall be under the jurisdiction of National Technical Committee 9 on

Explosion Protected Electrical Apparatus of Standardization Administration of China

(SAC/TC 9).

The drafting organizations of this document. Nanyang Explosion-proof Electrical

Research Institute Co., Ltd.; CCTEG Shenyang Institute; Shanghai Inspection and

Testing Institute of Instruments and Automation Systems Co., Ltd.; CCTEG Chongqing

Engineering Co., Ltd.; Wolong Electric Nanyang Explosion Protection Group Co., Ltd.;

Sunleem Technology Incorporated Company; WAROM Technology Incorporated

Company; FEICE Explosion-proof Electric Co., Ltd.; CZ Explosion-proof Electric

Appliances Co., Ltd.; Nanyang Zhongtian Explosion-proof Electric Co., Ltd.

1 Scope

This document gives the specific requirements for the construction, testing and

marking of electrical equipment, parts of electrical equipment and Ex components with

the type of protection encapsulation "m" intended for use in explosive gas atmospheres

or explosive dust atmospheres.

2 Normative References

The contents of the following documents constitute indispensable clauses of this

document through normative references in the text. In terms of references with a

specified date, only versions with a specified date are applicable to this document. In

terms of references without a specified date, the latest version (including all the

modifications) is applicable to this document.

GB/T 1408.1 Electrical Strength of Insulating Materials - Test Methods - Part 1.Tests

at Power Frequencies (GB/T 1408.1-2016, IEC 60243-1.2013, IDT)

GB/T 3836.1 Explosive Atmospheres - Part 1.Equipment - General Requirements

(GB/T 3836.1-2021, IEC 60079-0.2017, MOD)

3 Terms and Definitions

For the purposes of this document, the terms and definitions given in GB/T 3836.1 and

the following definitions apply.

moisture, gas and dust tight permanent bonding of a compound to a surface.

insulation material, which is extruded or molded, but not poured.

4 General

The working voltage at any point in the circuit shall not exceed 1 kV.

5 Requirements for Compounds

Either the compound shall be tested in accordance with 8.1.1 or, if this test is not

performed, the certificate number for the equipment shall include the "X" suffix in

accordance with the marking requirements of GB/T 3836.1 and the specific conditions

of use listed on the certificate shall detail the precautions necessary.

Where the dielectric strength according to GB/T 1408.1 at the maximum service

temperature according to 8.2.2 a), of the compound is not available from the material

manufacturer, a test shall be performed in accordance with 8.1.2.

6 Temperatures

Where the equipment may be subject to fault in accordance with 7.2.1, or where there

is the possibility of an increased temperature, for example by an unfavorable input

voltage in accordance with 7.2.1 or an unfavorable load, this shall be considered in

determining the limiting temperatures.

7 Constructional Requirements

For levels of protection "ma" and "mb" the following components shall be considered

as not to fail if they are encapsulated according to the requirements of this standard, if

they are suitable for the service temperature and if they are not operated at more than

2/3 of their rated voltage, rated current and rated power related to the rating of the

device, the mounting conditions and the temperature range specified.

8 Type Tests

After testing, the sample shall be subjected to a visual inspection. Visible displacement

of the cable, which affects the type of protection, shall not be evident. No damage to

the compound or cable that could impair the type of protection shall be evident, for

example, cracks in the compound, exposure of the encapsulated components or failure

of adhesion.

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