AS 3007.2-1987

1 - AS 3007.2-1987 ELECTRICAL INSTALLATIONS-SURFACE MINES AND ASSOCIATED PROCESSING PLANT - GENERAL PROTECTION REQUIREMENTS
4 - PREFACE
5 - CONTENTS
8 - SCOPE OF PART
8 - REFERENCED DOCUMENTS
9 - SECTION 1. PROTECTION AGAINST DIRECT CONTACT
9 - INTRODUCTION.
9 - 1 GENERAL REQUIREMENTS.
9 - 1.1 Exceptions to the general requirements.
9 - 2 COMPLETE PROTECTION BY MEANS OF BARRIERS OR ENCLOSURES.
9 - 2.0 General.
9 - 2.1 Protection from live parts.
9 - 2.2 Strength and stability of barriers and enclosures.
10 - 2.3 Access to installation.
11 - 3 COMPLETE PROTECTION BY INSULATION OF LIVE PARTS.
11 - 3.1 Degree of insulation.
11 - 3.2 Type of insulation.
11 - 4 PARTIAL PROTECTION BY PLACING LIVE PARTS OUT OF REACH.
11 - 5 PARTIAL PROTECTION BY THE PROVISION OF OBSTACLES.
11 - 6 MINIMUM DISTANCES TO BE OBSERVED IN OPERATING AND MAINTENANCE GANGWAYS FOR INDOOR INSTALLATIONS.
11 - 6.1 Minimum distances.
11 - 6.2 Minimum width.
11 - 6.3 Access.
11 - 7 MINIMUM CLEARANCES FOR OUTDOOR INSTALLATIONS.
11 - 7.1 Application.
11 - 7.2 Minimum clearances to boundary fences.
11 - 7.3 Minimum clearances from accessible areas.
12 - 7.4 Minimum clearances to barriers.
17 - SECTION 2. PROTECTION AGAINST INDIRECT CONTACT - A. C.
17 - INTRODUCTION.
17 - 8 GENERAL.
17 - 8.1 Use of protective conductors.
17 - 8.2 Automatic disconnection of supply.
17 - 8.3 Characteristics of protection.
17 - 8.4 Protective measures other than use of protective conductors.
17 - 8.5 Distinction of supply to fixed and portable or mobile apparatus.
18 - 8.6 Disconnection time for systems above 1000 V.
18 - 8.7 Coordination of protection.
18 - 8.8 Exemption from use of protective conductors.
18 - 9 TN, TT AND IT SYSTEMS DESCRIPTION.
18 - 9.1 General.
18 - 9.2 Description of the systems.
18 - 10 PROTECTIVE MEASURESFOR TNSYSTEMS.
18 - 10.0 General.
18 - 10.1 Bonding of exposed conductive parts.
23 - 10.2 Disconnection following fault.
23 - 10.3 Single conductor as combined protective and neutral conductor.
23 - 10.4 Interruption of combined protective and neutral conductor.
23 - 10.5 Separation of protective conductor from a combined protective and neutral conductor.
23 - 10.6 Conductor identification.
23 - 10.7 Protective devices.
24 - 10.8 Residual-current-operated protective devices.
24 - 10.9 Voltage balance.
24 - 11 PROTECTIVEMEASURES FOR TT SYSTEMS.
24 - 11.0 General.
24 - 11.1 Neutral conductor insulation and installation.
24 - 11.2 Bonding of exposed conductive parts.
24 - 11.3 Conditions to be fulfilled following a fault.
24 - 11.4 Protective devices.
24 - 12 PROTECTIVE MEASURES FOR IT SYSTEMS.
24 - 12.0 General.
25 - 12.1 Isolation or earthing of the power system earthable point.
25 - 12.2 Neutral conductor insulation and installation.
25 - 12.3 Bonding of exposed conductive parts.
25 - 12.4 Operation of the protective devices under fault condition.
25 - 12.5 Protective devices.
25 - 13 REQUIREMENTS FOR EARTH FAULT CURRENT LIMITATION DEVICES.
25 - 13.0 General.
25 - 13.1 Neutral earthing resistors.
25 - 13.2 Neutral earthing reactors and arc suppression coils.
25 - 13.3 Three-phase earth fault current limiting neutral displacement reactor (zero sequence reactor).
25 - 14 EARTHING ARRANGEMENTS AND PROTECTIVE CONDUCTORS.
25 - 14.1 General requirements.
25 - 14.1.1 Performance of earthing arrangements.
26 - 14.1.2 Required components.
26 - 14.1.3 Design, selection and installation.
26 - 14.1.4 Precautions against damage due to electrolysis.
26 - 14.2 Earth electrodes.
26 - 14.2.1 Acceptable types.
26 - 14.2.2 Material and cross-sectional area.
26 - 14.2.3 Type and embedded depth.
26 - 14.2.4 Design of electrodes.
26 - 14.2.5 Allowance for deterioration.
26 - 14.2.6 Measurement of earth resistance.
26 - 14.2.7 Use of metallic pipe systems.
26 - 14.2.8 Use of metallic coverings of cables.
26 - 14.3 Earthing conductors.
26 - 14.3.1 Minimum cross-sectional area.
28 - 14.3.2 Connections to earth electrodes.
28 - 14.4 Main earthing terminals or bars.
28 - 14.4.1 Recommended connection facilities.
28 - 14.4.2 Means of disconnection.
28 - 14.4.3 Current carrying capacity.
28 - 14.5 Interconnection with earthing arrangements of other systems.
28 - 14.5.1 High voltage systems.
28 - 14.5.2 Lightning protection systems.
28 - 14.6 Protective conductors.
28 - 14.6.1 Types of protective conductor.
28 - 14.6.2 Minimum cross-sectional area.
29 - 14.6.3 Preservation of electrical continuity of protective conductors.
29 - 14.7 Earthing arrangements for protective purposes.
29 - 14.7.1 Protective conductors used with overcurrent-operated protective devices.
29 - 14.7.2 Earthing and protective conductors for fault-voltage-operated protective devices.
29 - 14.8 Equipotential bonding.
29 - 14.8.1 Main equipotential bonding.
30 - 14.8.2Supplementary equipotential bonding.
31 - SECTION 3. PROTECTION AGAINST OVERCURRENT
31 - INTRODUCTION.
31 - 15 GENERAL RULE.
31 - 16 NATURE OF PROTECTIVE DEVICES.
31 - 16.1 Devices ensuring protection against both overload current and short-circuit current.
31 - 16.2 Devices ensuring protection against overload current only.
31 - 16.3 Devices ensuring protection against short-circuit current only.
31 - 17 AUTOMATIC INTERRUPTION - PROTECTION AGAINST OVERCURRENT DUE TO OVERLOAD
31 - 17.1 Conditions of application.
31 - 17.2 Rating of protective devices and conductors.
32 - 17.3 Arrangement of the overload protective device.
32 - 17.3.1 Electrical apparatus and live conductors.
32 - 17.3.2 Live conductors.
32 - 18 AUTOMATIC INTERRUPTION - PROTECTION AGAINST SHORT CIRCUITS.
32 - 18.1 Conditions of application.
32 - 18.2 Determination of prospective short-circuit currents.
32 - 18.3 Operating requirements for short-circuit protection.
33 - 18.4 Arrangements of devices for short-circuit protection only.
33 - 19 COORDINATION OF OVERLOAD AND SHORT-CIRCUIT PROTECTION.
33 - 19.1 Protection afforded by one device.
33 - 19.2 Protection afforded by separate devices.
33 - 20 LIMITATION OF OVERCURRENT BY CHARACTERISTICS OF SUPPLY OR LOAD.
33 - 20.1 Limitation by nature of the load.
33 - 20.2 Limitation by nature of the source.
34 - SECTION 4. SELECTION OF PROTECTIVE DEVICES AND PROTECTION SYSTEMS
34 - INTRODUCTION.
34 - 21 BASIC REQUIREMENTS.
34 - 21.1 Fuses.
34 - 21.2 Operating characteristics.
34 - 22 SELECTION PROCEDURE.
34 - 22.1 Selection of protection systems.
34 - 22.2 Selection of devices for protection against short circuits.
34 - 22.3 Selection of devices for protection against overload.
34 - 22.4 Selection against indirect contact.
34 - 23 DISCRIMINATION BETWEEN PROTECTIVE DEVICES.
37 - APPENDIX A - SELECTION OF FACTOR k FOR CALCULATING THE MINIMUM CROSS-SECTIONAL AREA OF PROTECTIVE CONDUCTORS.
37 - A1 PROCEDURE FOR SELECTING VALUES.
37 - A2 SUGGESTED INITIAL TEMPERATURES.
38 - A3 SUGGESTED FINAL TEMPERATURES.
39 - APPENDIX B - DESCRIPTION OF CERTAIN TYPES OF PROTECTIVE DEVICES AND THEIR USES
39 - B1 MEASURING TRANSFORMERS.
39 - B2 RESIDUAL CURRENT OPERATED PROTECTIVE DEVICES.
39 - B3 RESIDUAL VOLTAGE OPERATED PROTECTIVE DEVICES.
39 - B4 FAULT VOLTAGE OPERATED PROTECTIVE DEVICES.
39 - B5 COMBINED RESIDUAL CURRENT/VOLTAGE OPERATED PROTECTIVE DEVICES.
39 - B6 INSULATION MONITORING DEVICES.
39 - B7 DISTANCE RELAYS.
40 - B8 DIFFERENTIAL PROTECTION.
40 - B9 OVERCURRENT OPERATED PROTECTIVE DEVICES.
41 - ANNEX - SUMMARY OF TECHNICAL DEVIATIONS BETWEEN THIS STANDARD AND IEC 621-2*

Specifies the measures which are required for protection against electric shock in normal service from direct contact with live parts, for protection against electric shock from parts which may become live in the case of a fault, and for protection against the effects of over-current and fault current resulting from overload or short-circuit conditions. Includes requirements for the selection of protective devices and protection systems. Technically equivalent to IEC 621-2.

This standard prescribes general protection requirements for electrical installations within the scope of AS 3007.1. It outlines the measures which are required for protection against electric shock in normal service from direct contact with live parts; for protection against electric shock from parts which may become live in the event of a fault (indirect contact); and for protection against the effects of overcurrent resulting from overload or short-circuit conditions.