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.