HB 242-2007

1 - HB 242-2007 HIGH VOLTAGE MINING EQUIPMENT FOR USE UNDERGROUND
4 - PREFACE
5 - CONTENTS
7 - SECTION 1 SCOPE AND GENERAL
7 - 1.1 PURPOSE
7 - 1.2 SCOPE
7 - 1.3 REFERENCED STANDARDS
8 - 1.4 DEFINITIONS
8 - 1.4.1 Active (or active conductor)
8 - 1.4.2 Area, hazardous
8 - 1.4.3 Area, non-hazardous (safe)
8 - 1.4.4 Authorised person
8 - 1.4.5 Barrier (screen)
8 - 1.4.6 Circuit-breaker
9 - 1.4.7 Circuit interrupting device
9 - 1.4.8 Clearance
9 - 1.4.9 Competent person
9 - 1.4.10 Continuous rating
9 - 1.4.11 Creepage distance
9 - 1.4.12 Current, overload
9 - 1.4.13 Current, short-circuit
9 - 1.4.14 Direct contact
9 - 1.4.15 Disconnect switch
9 - 1.4.16 Earth continuity protection system
9 - 1.4.17 Earth/static discharging stick
9 - 1.4.18 Earth fault current
9 - 1.4.19 Earth-fault current limitation
10 - 1.4.20 Earth-fault protection
10 - 1.4.21 Earthable point
10 - 1.4.22 Earthed
10 - 1.4.23 Electrical equipment
10 - 1.4.24 Electrical installation
10 - 1.4.25 Enclosure
10 - 1.4.26 Equipotential bonding
10 - 1.4.27 Examination
10 - 1.4.28 Fault current
10 - 1.4.29 Feeder cable
10 - 1.4.30 High voltage
10 - 1.4.31 Indirect contact
10 - 1.4.32 Instructed persons
11 - 1.4.33 Insulated
11 - 1.4.34 International protection (IP) classification
11 - 1.4.35 Leakage current (in an installation)
11 - 1.4.36 Lockout earth-fault protection
11 - 1.4.37 Maintenance
11 - 1.4.38 Mobile machine
11 - 1.4.39 Neutral conductor (symbol N)
11 - 1.4.40 Ordinary persons
11 - 1.4.41 Plant
11 - 1.4.42 Portable equipment
11 - 1.4.43 Prospective touch voltage
12 - 1.4.44 Protection device
12 - 1.4.45 Protective earthing conductor
12 - 1.4.46 Reeling and trailing cable
12 - 1.4.47 Restrained plug and receptacle
12 - 1.4.48 Safe work method statement
12 - 1.4.49 Shunt release
12 - 1.4.50 Skilled persons
12 - 1.4.51 Substation
12 - 1.4.52 Switchgear
12 - 1.4.53 Transportable equipment
12 - 1.4.54 Undervoltage release
13 - 1.4.55 Working earths
13 - 1.5 APPLICABLE LEGISLATION
14 - SECTION 2 HAZARD IDENTIFICATION AND RISK ASSESSMENT
14 - 2.1 HAZARD ASSESSMENT
14 - 2.2 CONSULTATION
15 - SECTION 3 HV SAFETY MANAGEMENT PLAN
15 - 3.1 GENERAL
15 - 3.2 ELEMENTS
16 - SECTION 4 ELECTRICAL PROTECTION
16 - 4.1 STRATEGY
16 - 4.2 SECTIONALISING THE DISTRIBUTION SYSTEM
17 - 4.3 EARTH-CONTINUITY PROTECTION
17 - 4.4 EARTH-FAULT LIMITATION
21 - 4.5 EARTH-LEAKAGE PROTECTION
21 - 4.6 SHORT CIRCUIT
21 - 4.7 OVERCURRENT/OVERLOAD PROTECTION
21 - 4.7.1 Overcurrent protection
21 - 4.7.2 Overload protection
22 - 4.7.3 Current transformer (CT) considerations
22 - 4.8 EARTH-FAULT LOCKOUT
22 - 4.9 RESETS
22 - 4.10 MAINTENANCE AND TESTING OF PROTECTION DEVICES
23 - SECTION 5 HIGH VOLTAGE ISOLATION
23 - 5.1 ISOLATION AND SWITCHING DEVICES
23 - 5.1.1 General recommendations
23 - 5.1.2 Isolation devices for electrical work
24 - 5.1.3 Isolation for mechanical maintenance of equipment
25 - 5.1.4 Devices for emergency stopping
26 - 5.1.5 Devices for functional (control) switching
26 - 5.2 ISOLATION PRACTICES FOR ELECTRICAL WORK
26 - 5.2.1 Training and competency
26 - 5.2.2 HV access procedures-lockout and tagging
26 - 5.2.3 Operator protection
27 - 5.2.4 Environment for operating HV switch gear
27 - 5.2.5 Work crew protection
28 - SECTION 6 ENCLOSURES
28 - 6.1 ARC FAULT CONTAINMENT
28 - 6.1.1 Flameproof equipment
29 - 6.1.2 IP enclosures
29 - 6.2 CREEPAGE AND CLEARANCE
30 - 6.3 MINIMUM FREE DISTANCE
30 - 6.4 PERMITTED TECHNIQUES
30 - 6.5 IP CONSIDERATIONS
31 - SECTION 7 DISTRIBUTION AND CONTROL ARRANGEMENTS
31 - 7.1 GENERAL
31 - 7.2 MAIN DISCONNECTING SWITCH
31 - 7.3 TRAILING CABLE DISCONNECTING SWITCHES
31 - 7.4 DISCONNECTING SWITCHES
31 - 7.4.1 Rating
32 - 7.4.2 Visible break
32 - 7.4.3 Working earths
33 - 7.4.4 Provision for locking
33 - 7.4.5 Labelling
33 - 7.5 BARRIERS AND COVERS
33 - 7.6 COVER INTERLOCKS
33 - 7.7 EMERGENCY°STOP SWITCH
33 - 7.8 CAUTION LABELS
34 - SECTION 8 RETICULATION
34 - 8.1 INSTALLATION AND SAFEGUARDING OF CABLES
34 - 8.1.1 General
34 - 8.1.2 Feeder cables
35 - 8.1.3 Ring mains and parallel feeds
35 - 8.1.4 Multiple feeds
35 - 8.1.5 Trailing cables
37 - 8.1.6 Temporary storage of trailing cables
37 - 8.1.7 Safeguarding of cables
37 - 8.2 TRAILING CABLE HANDLING AND PULLING
37 - 8.2.1 Handling
37 - 8.2.2 Pulling
38 - 8.2.3 HV testing
40 - 8.2.4 Repair of cables
41 - SECTION 9 MOBILE MACHINES AND MOTORS
41 - 9.1 GENERAL
41 - 9.2 ELECTRICAL ENCLOSURES
41 - 9.3 MACHINE SWITCHING DEVICES
41 - 9.4 BARRIERS
41 - 9.5 ELECTRICAL INTERLOCKING
41 - 9.6 EMERGENCY SWITCHING
42 - 9.7 HV MACHINE CABLES
42 - 9.8 CABLE ANCHOR POINT
42 - 9.9 EARTHING
42 - 9.10 VARIABLE SPEED DRIVES (VSD)
42 - 9.10.1 General
42 - 9.10.2 Problems
43 - 9.10.3 Issues
43 - 9.10.4 Other considerations
44 - SECTION 10 TRANSPORTING HIGH VOLTAGE EQUIPMENT
44 - 10.1 GENERAL
44 - 10.2 CABLES
44 - 10.2.1 General
44 - 10.2.2 Paper insulated lead sheathed steel wire armoured (PILSSWA) cables
44 - 10.2.3 XLPE
44 - 10.2.4 Rubber cables to AS/NZS 1802
44 - 10.2.5 Installations, recovery and storage
48 - 10.3 OTHER HIGH VOLTAGE EQUIPMENT
49 - SECTION 11 COMMISSIONING PROCEDURES
49 - 11.1 GENERAL
49 - 11.2 FIRST TIME COMMISSIONING
49 - 11.3 RECOMMISSION/DECOMMISSION
51 - SECTION 12 OPERATING PROCEDURES SWITCHGEAR/EQUIPMENT
51 - 12.1 OPERATING PROCEDURES FOR OPERATORS OF HV MACHINES
52 - 12.2 OPERATING PROCEDURES FOR ELECTRICAL MAINTENANCE AND/OR REPAIR OF HV EQUIPMENT
54 - SECTION 13 INSPECTION AND MAINTENANCE
54 - 13.1 TROUBLESHOOTING AND TESTING
54 - 13.1.1 General
54 - 13.1.2 Trailing cable and mining machine electrical work procedures
55 - 13.1.3 Trailing cable troubleshooting and testing
55 - 13.1.4 DCB electrical work procedures
56 - 13.1.5 HV access procedures - lockout and tagging
56 - 13.2 MAINTENANCE OF HV SYSTEMS
56 - 13.2.1 General
56 - 13.2.2 Safety
57 - 13.2.3 Items to be considered
57 - 13.2.4 Trailing cable inspections
57 - 13.2.5 Maintenance on HV switchgear
57 - 13.2.6 Special considerations for SF6 switchgear
59 - APPENDIX A - TOUCH POTENTIAL CALCULATIONS FOR A HIGH VOLTAGE AFC
59 - A1 FACTORS AFFECTING TOUCH POTENTIAL
59 - A2 EXAMPLE
59 - A3 CALCULATION
61 - A4 CALCULATION FOR A BROADER RANGE OF VALUES
65 - APPENDIX B - PLANT STANDARDS
66 - APPENDIX C - USEFUL PUBLICATIONS
66 - C1 DESIGN & TESTING
66 - C2 APPLICATION
68 - APPENDIX D - EXAMPLES OF SAFETY ALERTS INVOLVING HV EQUIPMENT

This Handbook outlines safety guidelines for electrical mining equipment where the voltage of the supply system is above 1200 V and covers non-hazardous and hazardous area applications. It contains provisions relating to equipment design, commissioning, operation, and maintenance of such equipment. This Handbook should be read in conjunction with the joint Australian and New Zealand Standard AS/NZS 4871.

This Handbook outlines safety guidelines for electrical mining equipment where the voltage of the supply system is above 1200 V and covers non-hazardous and hazardous area applications. It contains provisions relating to equipment design, commissioning, operation, and maintenance of such equipment. This Handbook should be read in conjunction with the joint Australian and New Zealand Standard AS/NZS 4871. Recommendations for plant Standards are contained in Appendix B, while useful publications are noted in Appendix C. Appendix D provides examples of safety alerts involving HV equipment.

First published as HB 242-2007.