This part of GB 3836 specifies requirements for the construction, testing and marking for Group II electrical equipment with type of protection, "n" intended for use in explosive gas atmospheres. This part applies to electrical equipment where the rated voltage does not exceed 15 kV r.m.s. a.c. or d.c.
This part of GB 3836 is applicable to non-sparking electrical equipment and also to electrical equipment with parts or circuits producing arcs or sparks or having hot surfaces which, if not protected in one of the ways specified in this standard, could be capable of igniting a surrounding explosive gas atmosphere. This standard describes several different methods by which this can be achieved which may be combined with other methods described in GB 3836.1-2010.
This standard supplements and modifies the general requirements of GB 3836.1-2010, except as indicated in Table 1. Where a requirement of this standard conflicts with a requirement of GB 3836.1-2010, the requirement of this standard takes precedence.
Table 1 Relationship of This Part to GB 3836.1-2010
Clause of GB 3836.1-2010 GB 3836.1-2010 clause application to GB 3836.8
GB 3836.1-2010
(informative) Clause / Subclause title
(normative) Protected sparking
nC Non sparking nA Restricted breathing
nR
4 Equipment grouping Applies Applies Applies
4.1 Group I Excluded Excluded Excluded
4.2 Group II Applies Applies Applies
4.3 Group III Excluded Excluded Excluded
4.4 Equipment for a particular explosive atmosphere Applies Applies Applies
5.1 Environmental influences Applies Applies Applies
5.1.1 Ambient temperature Applies Applies Applies
5.1.2 External source of heating or cooling Applies Applies Applies
5.2 Service temperature Applies Applies Applies
5.3.1 Determination of maximum surface temperature Applies Applies Applies
5.3.2.1 Group I electrical equipment Excluded Excluded Excluded
5.3.2.2 Group II electrical equipment Applies Applies Applies
5.3.2.3 Group III electrical equipment Excluded Excluded Excluded
5.3.3 Small component temperature for Group I and Group II electrical equipment Applies Applies Excluded
6.1 General Applies Applies Applies
6.2 Mechanical strength Applies Applies Applies
6.3 Opening times Excluded Excluded Applies
6.4 Circulating currents Applies Applies Applies
6.5 Gasket retention Applies Applies Applies
6.6 Electromagnetic and ultrasonic radiating equipment Applies Applies Applies
7.1.1 Applicability Applies Applies Applies
7.1.2 Specification of materials Applies Applies Applies
7.1.3 Plastic materials Applies Applies Applies
7.1.4 Elastomeric materials Applies Applies Applies
7.2 Thermal endurance Applies Applies Applies
7.3 Resistance to light Applies Applies Applies
7.4 Electrostatic charges on external non-metallic materials Applies Applies Applies
7.5 Threaded holes Applies Applies Applies
8.1.1 Group I Excluded Excluded Excluded
8.1.2 Group II Applies Applies Applies
8.1.3 Group III Excluded Excluded Excluded
8.2 Threaded holes Applies Applies Applies
9.1 General Applies Applies Applies
9.2 Special fasteners Excluded Excluded Excluded
9.3 Holes for special fasteners Excluded Excluded Excluded
10 Interlocking devices Excluded Excluded Excluded
11 Bushings Applies Applies Applies
12 Materials used for cementing Modified Modified Modified
13 Ex components Applies Applies Applies
14 Connection facilities and termination compartments Modified Modified Modified
15 Connection facilities for earthing and bonding conductors Applies Applies Applies
16 Entries into enclosures Applies Applies Applies
17 Supplementary requirements for rotating electrical machines Excluded Modified Excluded
18 Supplementary requirements for switchgear Applies Applies Applies
19 Supplementary requirements for fuses Modified Modified Modified
20 Supplementary requirements for plugs and sockets Modified Modified Modified
21 Supplementary requirements for luminaires Modified Modified Modified
22 Supplementary requirements for caplights and handlights Applies Applies Applies
23 Equipment incorporating cells and batteries Modified Modified Modified
24 Documentation Applies Applies Applies
25 Compliance of prototype or sample with documents Applies Applies Applies
26.1 General Applies Applies Applies
26.2 Test configuration Applies Applies Applies
26.3 Tests in explosive test mixtures Applies Applies Applies
26.4 Tests of enclosures Applies Applies Applies
26.4.1.1 Metallic enclosures, metallic parts of enclosures and glass parts of enclosures Applies Applies Applies
26.4.1.2.1 Group I electrical equipment Excluded Excluded Excluded
26.4.1.2.2 Group II and Group III electrical equipment Applies Applies Applies
26.4.2 Resistance to impact Applies Applies Applies
26.4.3 Drop test Applies Applies Applies
26.4.4 Acceptance criteria Applies Applies Applies
26.4.5 Degree of protection by enclosure Applies Applies Applies
26.5 Thermal tests Applies Applies Applies
26.6 Torque test for bushings Applies Applies Applies
26.7 Non-metallic enclosures or non-metallic parts of enclosures Modified Modified Modified
26.8 Thermal endurance to heat Modified Modified Modified
26.9 Thermal endurance to cold Applies Applies Applies
26.10 Resistance to light Applies Applies Applies
26.11 Resistance to chemical agents for Group I electrical equipment Excluded Excluded Excluded
26.12 Earth continuity Applies Applies Applies
26.13 Surface resistance test of parts of enclosures of non-metallic materials Applies Applies Applies
26.14 Charging tests Applies Applies Applies
26.15 Measurement of capacitance Applies Applies Applies
27 Routine tests Applies Applies Applies
28 Manufacturers responsibility Applies Applies Applies
29 Marking Applies Applies Applies
30 Instructions Applies Applies Applies
Annex A Supplementary
requirements for Ex cable glands Applies Applies Applies
Annex B Requirements for Ex components Applies Applies Applies
Annex G Example of rig for resistance to impact test Applies Applies Applies
Annex E Introduction to an alternative risk assessment method encompassing “equipment protection levels” fro Ex equipment Applies Applies Applies
Applies : this requirement of GB 3836.1-2010 is applied without change.
Excluded : this requirement of GB 3836.1-2010 does not apply.
Modified : this requirement of GB 3836.1-2010 is modified as detailed in this standard.
Note 1: The clause number in the above table is shown for information only. The applicable requirements of GB 3836.1-2010 are identified by the clause title which is normative. This document was written against the specific requirements of GB 3836.1-2010). The clause numbers for the previous edition are shown for information only. This is to enable the General Requirements GB 3836.1-2010) to be used where necessary with this part.
Note 2: A non-incendive component is limited in use to the particular circuit for which it has been shown to be non-ignition capable and, therefore, cannot be separately assessed as complying with this standard.
Note 3: Compliance with this standard does not imply any removal of, or lowering of the requirements of any other standard with which the electrical equipment complies.
Note 4: This part supplements, and may enhance, the requirements for equipment for normal industrial applications. Where compliance with other IEC standards is indicated, such as GB 755-2008 for motors and GB 7000 for luminaires, proving compliance to those standards is normally the responsibility of the manufacturer.
Note 5: Type of protection “n” provides Equipment Protection Level (EPL) Gc. For further information, see GB 3836.1-2010.
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 755-2008 Rotating Electrical Machines — Rating and Performance (IEC 60034-1:2004, IDT)
GB 1312-2007 Lampholders for Tubular Fluorescent Lamps and Starter Holders (IEC 60400:2004, IDT)
GB/T 1406.1-2008 Types and Dimensions of Lamp Caps — Part 1: Screw Caps (IEC 60061-1:2005, MOD)
GB/T 1406.2-2008 Types and Dimensions of Lamp Caps — Part 2: Pin Lamp Caps (IEC 60061-1:2005, MOD)
GB/T 1406.3-2008 Types and Dimensions of Lamp Caps — Part 3: Prefocus Caps (IEC 60061-1:2005, MOD)
GB/T 1406.4-2008 Types and Dimensions of Lamp Caps — Part 4: Miscellaneous Caps (IEC 60061-1:2005, MOD)
GB/T 1406.5-2008 Types and Dimensions of Lamp Caps — Part 5: Bayonet Caps (IEC 60061-1:2005, MOD)
GB/T 2423.5-1995 Environmental Testing for Electric and Electronic Products — Part 2: Test Methods — Test Ea and Guidance: Shock (idt IEC 60068-2-27:1987)
GB 3836.1-2010 Explosive Atmospheres — Part 1: Equipment — General Requirements (IEC 60079-0:2007, MOD)
GB 3836.2-2010 Explosive Atmospheres — Part 2: Equipment Protection by Fameproof Enclosures “d” (IEC 60079-1:2007, MOD)
GB 3836.3-2010 Explosive Atmospheres — Part 3: Equipment Protection by Increased Safety “e” (IEC 60079-7:2006, IDT)
GB 3836.4-2010 Explosive Atmospheres — Part 4: Equipment Protection by Intrinsic Safety “i” (IEC 60079-11:2006, MOD)
GB 3836.9-2014 Explosive Atmospheres — Part 9: Equipment Protection by Type of Protection “m” (IEC 60079-18:2009, MOD)
GB 3836.16-2006 Explosive Atmospheres — Part 16: Electrical Installations Inspection and Maintenance (IEC 60079-17:2002, IDT)
GB/T 3956-2008 Conductors of Insulated Cables (IEC 60228:2004, IDT)
GB/T 4207-2012 Method for the Determination of the Proof and the Comparative Tracking Indices of Solid Insulating Materials (IEC 60112:2009, IDT)
GB 4208-2008 Degrees of Protection Provided by Enclosure (IP Code) (IEC 60529:2001, IDT)
GB 7000 (all parts) Luminaires
GB 7000.1-2007 Luminaires — Part 1: General Requirements and Tests (IEC 60598-1:2003, IDT)
GB 13140.5-2008 Connecting Devices for Low-voltage Circuits for Household and Similar Purposes — Part 2: Particular Requirements for Twist-on Connecting Devices (IEC 60998-2-4:2004, IDT)
GB 13539.3-2008 Low-voltage Fuses — Part 3: Supplementary Requirements for Fuses for Use by Unskilled Persons (Fuses Mainly for Household and Similar Applications) — Examples of Standardized Systems of Fuses A to F (IEC 60269-3:2006, IDT)
GB/T 14048.7-2006 Low-voltage Switchgear and Controlgear — Part 7-1: Ancillary Equipment — Terminal blocks for Copper Conductors (IEC 60947-7-1:2002, MOD)
GB/T 14048.8-2006 Low-voltage Switchgear and Controlgear — Part 7-2: Ancillary Equipmentr — Protective Conductor Terminal Blocks for Copper Conductors (IEC 60947-7-2:2002, MOD)
GB/T 16935.1-2008 Insulation Coordination for Equipment within Low-voltage Systems — Part 1: Principles, Requirements and Tests (IEC 60664-1:2007, IDT)
GB 17464-2012 Connecting Devices — Electrical Copper Conductors — Safety Requirements for Screw-type and Screwless-type Clamping Units — Part 1: General Requirements and Particular Requirements for Clamping Units for Conductors from 0.2 mm2 up to 35 mm2 (Included) (IEC 60999-1:1999, IDT)
GB 17935-2007 Edison Screw Lampholders (IEC 60238:2004, IDT)
GB 17936-2007 Bayonet Lampholders (IEC 61184:2004, IDT)
GB 18489-2008 Capacitors for Use in Tubular Fluorescent and Other Discharge Lamp Circuits — General and Safety Requirements (IEC 61048-2006, IDT)
GB 18774-2002 Double-capped Fluorescent Lamps — Safety Specifications (idt IEC 61195:1999)
GB 19510.1-2009 Lamp Controlgear — Part 1: General and Safety Requirements (IEC 61347-1:2007, IDT)
GB 19510.2-2009 Lamp Controlgear — Part 2: Particular Requirements for Starting Devices (Other Than Glow Starters) (IEC 61347-2-1:2006, IDT)
GB 19510.3-2009 Lamp Controlgear — Part 3: Particular Requirements for d.c.or a.c. Supplied Electronic Step-down Convertors for Filament Lamps (IEC 61347-2-2:2006, IDT)
GB 19510.4-2009 Lamp Controlgear — Part 4: Particular Requirements for a.c. Supplied Electronic Ballasts for Fluorescent Lamps (IEC 61347-2-3:2000, IDT)
GB 19510.5-2005 Lamp Controlgear — Part 5: Particular Requirements for d.c. Supplied Electronic Ballasts for General Lighting (IEC 61347-2-4:2000, IDT)
GB 19510.8-2009 Lamp Controlgear — Part 8: Particular Requirements for d.c. Supplied Electronic Ballasts for Emergency Lighting (IEC 61347-2-7:2006, IDT)
GB 19510.9-2009 Lamp Controlgear — Part 9: Particular Requirements for Ballasts for Fluorescent Lamps (IEC 61347-2-8:2006, IDT)
GB 19510.10-2009 Lamp Controlgear — Part 10: Particular Requirements for Ballasts for Discharge Lamps (Excluding Fluorescent Lamps) (IEC 61347-2-9:2003, IDT)
GB/T 19655-2005 Auxiliaries for Lamps — Starting Devices (Other Than Glow Starters) — Performance Requirements (IEC 60927:1996, IDT)
GB 20550-2013 Glow-starters for Fluorescent Lamps (IEC 60155:2006, IDT)
GB/T 20636-2006 Connecting Device — Electrical Copper Conductors — Safety Requirements for Screw-type and Screwless-type Clamping Units — Particular Requirements for Conductors above 35mm2 up to 300mm2 (IEC 60999-2:2003, IDT)
GB/T 21209-2007 Guide for the Design and Performance of Cage Induction Motors Specifically Designed for Converter Supply (IEC/TS 60034-25:2004, IDT)
IEC 60034 (all parts) Rotating Electrical Machines
IEC 60061 (all parts) Lamp Caps and Holders Together with Gauges for the Control of Interchangeability and Safety
IEC 60079-29-2 Explosive Atmospheres — Part 29-2: Gas Detectors — Selection, Installation, Use and Maintenance of Detectors for Flammable Gases and Oxygen
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB 3836.1-2010 and the following apply.
3.1
Cable sealing box
Auxiliary enclosure provided specifically for the purpose of sealing the insulation of a cable (for example, oil insulated cable) where it is connected to an apparatus.
The enclosure may also provide for the connection of separate cable tails to the cable.
3.2
Clearance
Shortest distance in air between two conductive parts.
3.3
Creepage distance
Shortest distance along the surface of a solid insulating material in contact with air between two conductive parts.
3.4
Duty cycle
Repetitive variation of load in which the cycle time is too short for thermal equilibrium to be attained in the first cycle.
3.5
Separation
Shortest distance through solid insulating material between two conductive parts.
3.6
Sealing device
Device employing a method other than encapsulation to prevent the flow of a gas or a liquid between apparatus and a conduit by providing sealing facilities.
3.7
Type of protection "n"
Type of protection applied to electrical equipment such that, in normal operation and in certain specified regular expected occurrences, it is not capable of igniting a surrounding explosive gas atmosphere.
Note 1: Additionally, the requirements of this standard are intended to ensure that a malfunction capable of causing ignition is not likely to occur.
Note 2: An example of a specified regular expected occurrence is a luminaire with failed lamp.
3.7.1
Non-sparking device “nA”
Device constructed to minimize the risk of occurrence of arcs or sparks capable of creating an ignition hazard during conditions of normal operation.
Note: For the purposes of this standard normal operation is considered to exclude the removal or insertion of components with the circuit energized.
3.7.2
Devices and components “nC”
3.7.2.1
Enclosed-break device “nC”
Device incorporating electrical contacts that are made and broken and that will withstand an internal explosion of the flammable gas or vapour which may enter it without suffering damage and without communicating the internal explosion to the external flammable gas or vapour.
Note: The principle difference between enclosed break devices “nC” and flameproof “d” are that the dimensions are not controlled and that safety factors have not been added.
3.7.2.2
Hermetically-sealed device “nC”
Device which is so constructed that the external atmosphere cannot gain access to the interior and in which the seal is made by fusion, for example by soldering, brazing, welding or the fusion of glass to metal.
3.7.2.3
Non-incendive component “nC”
Components having contacts for making or breaking a specified ignition capable circuit but in which the contacting mechanism is designed and constructed so that the component is not capable of causing ignition of the specified explosive gas atmosphere.
Note: The enclosure of the non-incendive component is not intended to either exclude the explosive gas atmosphere or contain an explosion. This is usually applied to specially constructed switch contacts that are mechanically designed to quench any arc or spark so that they are not a source of ignition.
3.7.2.4
Sealed device “nC”
Device which is so constructed that it cannot be opened during normal service and is sealed effectively to prevent entry of an external atmosphere.
3.7.3
Rrestricted-breathing enclosure “nR”
Enclosure that is designed to restrict the entry of gases, vapours and mists.
3.8
Test port
Facility to test the integrity of restricted breathing equipment in the field after installation, during initial inspection and during maintenance.
