AS 1076.1-1977

1 - AS 1076, Part 1-1977 SELECTION, INSTALLATION AND MAINTENANCE OF ELECTRICAL APPARATUS AND ASSOCIATED EQUIPMENT FOR USE .....
4 - PREFACE
6 - CONTENTS
8 - FOREWORD
10 - SECTION 1. GENERAL PRINCIPLES
10 - 1.1 SCOPE OF PART
10 - 1.2 APPLICATION
10 - 1.3 DEFINITIONS
10 - 1.3.1 Combustible material
11 - 1.3.2 Explosive gas/air mixture
11 - 1.3.3 Explosive dust/air mixture
11 - 1.3.4 Hazard
11 - 1.3.5 Hazardous area
11 - 1.3.6 Non-hazardous area
11 - 1.3.7 Source of release
12 - 1.3.8 Flashpoint
12 - 1.3.9 Ignition temperature
12 - 1.3.10 Maximum surface temperature
12 - 1.3.11 Temperature class
12 - 1.3.12 Grouping of apparatus in Class I areas
13 - 1.3.13 Chemical compatibility
13 - 1.3.14 Glow temperature (of dusts)
13 - 1.3.15 Type of protection
13 - 1.3.16 Unprotected surface
13 - 1.3.17 Degrees of protection of enclosures
13 - 1.3.18 Portable apparatus
13 - 1.3.19 Transportable apparatus
13 - 1.3.20 Combustible gas
14 - 1.3.21 Combustible vapour
14 - 1.3.22 Combustible mist
14 - 1.3.23 Intrinsic safety (Ex i)
14 - 1.3.24 Flameproof enclosure (Ex d)
14 - 1.3.25 Gas or vapour exclusion (Ex p)
14 - 1.3.25.1 Pressurized enclosure
14 - 1.3.25.2 Purged enclosure
14 - 1.3.26 Protection by ventilation (Ex v)
14 - 1.3.26.1 Gas or vapour dilution
15 - 1.3.26.2 Heat dissipation
15 - 1.3.27 Oil-immersed equipment (Ex o)-
15 - 1.3.28 Sand-filled enclosure (Ex q)-
15 - 1.3.29 Hermetically sealed equipment (Ex h)-
15 - 1.3.30 Protection by encapsulation (Ex c)-
15 - 1.3.31 Increased safety protection (Ex e)-
15 - 1.3.32 Non-speaking equipment (Ex n)-
15 - 1.3.33 Dust-excluding ignition-proof enclosure (DIP)-
15 - 1.3.34 Type of Protection ‘s’: Special Protection-
16 - 1.4 STATUTORY REGULATION AND ELECTRICITY REGULATIONS
16 - 1.4.1 General.
16 - 1.4.2 Mining.
16 - 1.4.3 Industry Above Ground.
16 - 1.4.4 Other Regulatory Authorities.
16 - 1.5 CLASSIFICATION OF HAZARDOUS AREAS
16 - 1.5.1 Basis of Classification.
17 - 1.5.2 General Classes.
17 - 1.6 TOXIC RISKS
17 - 1.7 IGNITION SOURCES OTHER THAN THOSE ASSOCIATED WITH ELECTRICAL APPARATUS
17 - 1.8 CONSEQUENTIAL EFFECTS
18 - 1.9 PROTECTION AGAINST STATIC ELECTRICITY
18 - 1.10 PROTECTION AGAINST LIGHTNING
18 - 1.11 PROTECTION AGAINST ELECTROMAGNETIC RADIATION
18 - 1.12 LIGHT METALS AS CONSTRUCTIONAL MATERIALS
19 - SECTION 2. PREVENTION OF EXPLOSION
19 - 2.1 SCOPE OF SECTION.
19 - 2.2 GENERAL CONSIDERATIONS.
19 - 2.2.1 Occurrence of Fire or Explosion.
19 - 2.2.2 Probability of Fire or Explosion.
19 - 2.2.3 Exchange of Information.
19 - 2.2.4 Assessment of the Type and Extent of the Explosion Risk.
19 - 2.2.5 Methods of Protection.
20 - 2.2.6 Segregation.
20 - 2.2.7 Total Enclosure of Combustible Material.
20 - 2.2.8 Conditions of Control.
20 - 2.2.9 Certification and Assessment of Apparatus and System.
22 - 2.3 CLASS I HAZARDOUS GASES AND VAPOURS.
22 - 2.3.1 Zones of Class I Areas.
23 - 2.3.2 Apparatus Grouping in Class I Areas.
25 - 2.3.3 Temperature Classification.
25 - 2.3.4 Selection of the Type of Protection According to the Zone of Risk.
27 - 2.3.5 Procedure for Selecting the Electrical Apparatus.
27 - 2.3.5.1 Information required.
27 - 2.3.5.2 Selection of type of protection.
27 - 2.3.5.3 Apparatus grouping.
27 - 2.3.5.4 Protection against environmental hazards.
27 - 2.3.5.5 Ambient temperature limitations.
28 - 2.4 CLASS II HAZARDOUS DUSTS, FIBRES AND FLYINGS.
28 - 2.4.1 Division of Class II Areas.
29 - 2.4.2 Selection of the Type of Protection in Class II Areas According to the Division of Risk.
30 - 2.4.3 Procedure for Selecting the Electrical Apparatus in Class II Areas.
30 - 2.4.3.1 Information required.
30 - 2.4.3.2 Selection of type of protection.
30 - 2.4.3.3 Protection against environmental hazards.
30 - 2.4.3.4 Ambient temperature limitation.
31 - SECTION 3. GENERAL INSTALLATION REQUIREMENTS
31 - 3.1 SCOPE OF SECTION.
31 - 3.2 ACCESS FOR INSPECTION.
31 - 3.3 PLANS AND RECORDS.
31 - 3.4 ELECTRICAL RATINGS.
31 - 3.5 INSTALLATION OF APPARATUS.
32 - 3.6 INTEGRITY OF INSULATION.
32 - 3.7 EARTHING.
32 - 3.8 BONDING.
32 - 3.9 AUTOMATIC ELECTRICAL PROTECTION.
32 - 3.9.1 General.
32 - 3.9.2 Earth-fault Protection.
33 - 3.9.3 Installations Not Exceeding 650 V.
34 - 3.9.4 Location of Protection and Control Apparatus.
34 - 3.9.5 Unearthed Systems.
34 - 3.10 ISOLATION.
34 - 3.10.1 General.
35 - 3.10.2 Location of Means of Isolation.
35 - 3.11 EMERGENCY SUPPLIES.
35 - 3.12 WIRING SYSTEMS.
35 - 3.12.1 General Installation Requirements for Wiring Systems.
35 - 3.12.1.1 General.
35 - 3.12.1.2 Consideration of hazardous environment.
35 - 3.12.1.3 Types of wiring.
36 - 3.12.1.4 Electrical continuity of metallic enclosures, conduits, sheaths and armour.
36 - 3.12.1.5 Circuits traversing a hazardous area.
36 - 3.12.1.6 Contact with other equipment or pipework.
37 - 3.12.1.7 Location of wiring.
37 - 3.12.1.8 Flexible terminal connections to fixed apparatus.
37 - 3.12.1.9 Cables and conduits passing through floors.
37 - 3.12.1.10 Precautions with cableways.
37 - 3.12.1.11 Marking.
37 - 3.12.1.12 Overhead lines for power supply and telecommunication circuits.
38 - 3.12.1.13 Wiring entry.
38 - 3.12.1.14 Unused cable entries.
38 - 3.12.1.15 Interconnections.
38 - 3.12.1.16 Cable runs.
38 - 3.12.1.17 Glands and seals.
38 - 3.12.2 Factors Affecting Choice of Wiring System.
38 - 3.12.2.1 General.
39 - 3.12.2.2 Steel conduits.
39 - 3.12.2.3 Cables for underground installation.
39 - 3.12.2.4 Mineral-insulated metal-sheathed cables.
39 - 3.12.2.5 Plastics-insulated and armoured cables.
39 - 3.12.2.6 Telecommunication circuits.
39 - 3.12.3 Installation of Conduit Systems.
39 - 3.12.3.1 Type of conduit.
39 - 3.12.3.2 Elbows.
40 - 3.12.3.3 Conduit runs between hazardous and non-hazardous areas.
40 - 3.12.3.4 Surface-mounted conduit.
40 - 3.12.3.5 Joints in conduit.
40 - 3.12.3.6 Bends in conduit.
40 - 3.12.3.7 Additional requirements.
40 - 3.12.4 Installation of Cable Systems.
40 - 3.12.4.1 Conductor material.
40 - 3.12.4.2 Interruptions to cable runs.
40 - 3.12.4.3 Identification of cable trenches.
40 - 3.12.4.4 Cable runs between hazardous and non-hazardous areas.
41 - 3.12.4.5 Mechanical protection of cables.
41 - 3.12.4.6 Ambient temperature during installation.
41 - 3.12.4.7 Cable installation in open air.
41 - 3.12.4.8 Armoured cables.
42 - 3.12.4.9 Mineral-insulated metal-sheathed cables.
42 - 3.12.4.10 Aluminium-sheathed cables.
42 - 3.13 PORTABLE AND TRANSPORTABLE APPARATUS AND ITS CONNECTIONS.
42 - 3.13.1 Necessity for Certification.
42 - 3.13.2 Protection of Apparatus.
42 - 3.13.3 Safeguarding of Flameproof Plugs and Sockets.
42 - 3.14 FLEXIBLE CABLES AND CORDS.
42 - 3.14.1 Construction of Cables.
43 - 3.14.2 Ambient Temperature.
43 - 3.14.3 Clamping at Points of Entry to Apparatus and Plugs.
43 - 3.15 TESTS.
43 - 3.15.1 Installation Tests.
43 - 3.15.2 Periodical Electrical Tests.
45 - SECTION 4. INSPECTION AND MAINTENANCE
45 - 4.1 SCOPE OF SECTION.
45 - 4.2 GENERAL CONSIDERATIONS.
45 - 4.3 STAFF.
45 - 4.4 INSPECTION AND TESTING IN HAZARDOUS AREAS.
45 - 4.4.1 Apparatus to be Rendered Dead.
45 - 4.4.2 Check on Accumulation of Gas, Vapour and Dust.
46 - 4.5 PRECAUTIONS CONCERNING THE USE OF IGNITING AGENCIES.
46 - 4.6 PERIODICAL MECHANICAL INSPECTION.
46 - 4.7 MAINTENANCE REQUIREMENTS.
46 - 4.7.1 General.
46 - 4.7.2 Maintenance of Flexible Cables and Cords.
46 - 4.7.2.1 Storage of out-of-used cables and cords.
47 - 4.7.2.2 Inspection before and during use.
47 - 4.7.3 Precautions Against Corrosion.
47 - 4.7.4 Cleanliness.
47 - 4.7.5 Precautions Against Excessive Temperature Rise.
47 - 4.7.5.1 Freedom from deposits of dust.
47 - 4.7.5.2 Correct servicing of lighting fittings.
47 - 4.7.6 Alterations to Apparatus.
47 - 4.8 WITHDRAWAL FROM SERVICE.
48 - SECTION 5. PROPERTIES OF COMBUSTIBLE LIQUIDS, VAPOURS AND GASES
48 - 5.1 SCOPE OF SECTION.
48 - 5.2 MELTING POINT AND BOILING POINT.
48 - 5.3 VAPOUR DENSITY.
48 - 5.3.1 General.
49 - 5.3.2 Effects of Temperature Changes.
49 - 5.4 FLASHPOINT.
49 - 5.4.1 General.
50 - 5.4.2 Materials Having High Flashpoints.
50 - 5.4.3 Classification of Flashpoints.
50 - 5.5 EXPLOSIVE (FLAMMABLE) LIMITS.
50 - 5.6 EXPLOSIVE (FLAMMABILITY) RANGE.
55 - 5.7 EFFECT OF ENVIRONMENTS HAVING OTHER THAN NORMAL ATMOSPHERIC CONDITIONS.
55 - 5.8 IGNITION TEMPERATURE.
55 - 5.8.1 General.
55 - 5.8.2 Basis of Ignition Temperatures.
55 - 5.8.3 Use of Ignition Temperature.
56 - 5.9 TEMPERATURE CLASSIFICATION.
56 - 5.10 APPARATUS GROUPING.
56 - 5.11 GENERAL CONSIDERATIONS.
56 - 5.11.1 Relation Between Ignition Temperature and Maximum Surface Tempera-ture.
57 - 5.11.2 Mixtures of Compounds.
58 - 5.11.3 Mists.
58 - 5.11.4 Impurities.
59 - SECTION 6. PROPERTIES OF COMBUSTIBLE DUSTS, FLYINGS AND FIBRES*
60 - SECTION 7. MARKING OF APPARATUS
60 - 7.1 SCOPE OF SECTION.
60 - 7.2 MARKING REQUIREMENTS FOR APPARATUS.
62 - 7.3 IDENTIFICATION OF THE TYPE OF PROTECTION.
63 - 7.4 EXAMPLES OF MARKING OF APPARATUS.
63 - 7.4.1 General.
63 - 7.4.2 Flameproof Enclosure.
63 - 7.4.3 Increased Safety Apparatus.
64 - 7.4.4 Intrinsic Safety.
64 - 7.4.4.1 Self-contained intrinsically safe apparatus.
64 - 7.4.4.2 Intrinsically safe systems and associated safe-area apparatus.
64 - 7.4.5 Type of Protection ‘n’.
64 - 7.4.6 Other Types of Protection.
64 - 7.5 GENERAL NOTES ON MARKING.
64 - 7.5.1 Significance of the ‘Ex’ Symbol.
65 - 7.5.2 Certificate Number.
65 - 7.5.3 Component Approval.
65 - 7.5.4 Marking for Multiple Types of Protection.
67 - APPENDIX A DEGREES OF PROTECTION OF ENCLOSURES
67 - A1 CLASSIFICATION CODE.
67 - A2 ENCLOSURE MARKING.
68 - A3 PROTECTION OF PERSONS AGAINST CONTACT WITH LIVE OR MOVING PARTS INSIDE THE ENCLOSURE AND PROTECTION OF EQUIPMENT.....
69 - A4 PROTECTION OF EQUIPMENT AGAINST INGRESS OF LIQUID.
70 - A5 PROTECTION OF EQUIPMENT AGAINST MECHANICAL DAMAGE.
70 - A6 DEGREES OF PROTECTION.
70 - A7 PARTICULAR REQUIREMENTS FOR ROTATING ELECTRICAL MACHINES.
71 - APPENDIX B FRICTIONAL SPARKING RISKS WITH LIGHT METALS AND THEIR ALLOYS
73 - APPENDIX C CALCULATION OF THE FLAMMABILITY LIMITS FOR A MIXTURE OF GASES
73 - C1 LIMITS FOR SIMPLE MIXTURES.
74 - C2 LIMITS FOR COMPLEX INDUSTRIAL GAS MIXTURES.
80 - APPENDIX D CERTIFICATION STANDARDS AND RELEVANT SPECIFICATIONS AND CODES OF PRACTICE
80 - D1 DEVELOPMENTS IN INTERNATIONAL STANDARDS.
80 - D2 AUSTRALIAN STANDARDS BASED ON IEC PUBLICATIONS.
81 - D3 NATIONAL CERTIFYING BODY FOR ELECTRICAL APPARATUS FOR USE IN HAZARDOUS AREAS.
82 - D4 RELEVANT CODES OF PRACTICE AND RULES.
82 - D5 OTHER RELEVANT AUSTRALIAN STANDARDS.
84 - APPENDIX E LIST OF ORGANISATIONS AND REGULATIONS
84 - E1 AUSTRALIAN ELECTRICITY AUTHORITIES.
85 - E2 AUSTRALIAN STATE MINING AUTHORITIES.
86 - E3 REGULATIONS.
86 - E3.1 Mining Regulations.
87 - E3.2 Other Regulations.

Provides basic information on the selection of electrical apparatus, and its installation, alteration and maintenance to ensure safe use in areas where combustible materials are generated, prepared, processed, handled, stored or otherwise used, and which are therefore potentially hazardous. It supplements the requirements of Section 9 of AS 3000-SAA Wiring Rules.

This Part of the code offers guidance on the selection of electrical apparatus and associated equipment, and on its installation, alteration and maintenance to ensure safe use in areas where combustible materials are generated, prepared, processed, handled, stored or otherwise used, and which are therefore potentially hazardous. The term 'combustible material' (see Rule 1.3.1) includes gases, vapours, liquids, mists, solids and dusts, but does not include those materials which are inherently explosive. The latter may require special considerations which are beyond the scope of the code. The recommendations of the code do not apply to the underground mining industry for which other precautions are necessary. It is recognised, however, that the recommendations of the code may be applied to certain parts of the surface mining industries.Precautions which may be necessary against the effects of static electricity and against lightning are also outside the scope of this code, except for the general recommendations indicated in Rules 1.8 and 1.9.

Obsolescent 1991 (Use AS 2381.1-1991)