Electric Shock Final Report

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Electric Shock Prevention Project

Final Report


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Electric shock prevention project

1 Table Of Contents

1 TABLE OF CONTENTS I

2 ACKNOWLEDGMENTS 1

3 EXECUTIVE SUMMARY 2

3.1 List of recommendations 23.1.1 Fit For Purpose equipment 23.1.2 Competency of people doing electrical work and welding 33.1.3 Procedures 33.1.4 Management systems 43.1.5 Legislation 4

4 ABBREVIATIONS AND DEFINITIONS 5

4.1 Abbreviations 5

4.2 Definitions 5

5 INTRODUCTION 7

5.1 Electric shock 75.1.1 Effects of electric shock 75.1.2 Types of electric shock 7

5.1.3 Causes of shock 8

5.2 Assessment project 85.2.1 Terms of reference 95.2.2 The project team 9

6 BACKGROUND AND CONTEXT 10

6.1 Electrical inspectors 10

6.2 Philosophy of operation 10

6.3 Electrical engineering safety 11

7 METHODOLOGY 12

7.1 Referenced documents 12

7.2 Electric shock victim management procedure 13

7.3 Management of electrical engineering safety 137.3.1 Risk management 137.3.2 Ownership of electrical work 13

7.4 AS 3000 and AS 3007 audits 13

7.5 Competence 13

7.6 Commissioning and testing 14

7.7 Electrical maintenance 14

7.8 Portable apparatus 14

7.9 Isolation 14

7.10 Welding 14

7.11 Site compliance inspections 157.12 Process 15

7.13 Actions 15

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Electric shock prevention project

8 FINDINGS AND RECOMMENDATIONS 16

8.1 Role of electricity in mining 16

8.2 Procedure for the management of victims of electric shock 16

8.3 Management of electrical engineering safety 178.3.1 Risk management 17

8.3.2 Ownership of electrical engineering safety 17

8.4 AS/NZS 3000 and AS 3007 audits 17

8.5 Competency standards 188.5.1 Knowledge and Training 19

8.6 Commissioning and testing 198.6.1 Test equipment 20

8.7 Maintenance 21

8.8 Portable Electrical Apparatus 24

8.9 Isolation 28

8.9.1 Internal isolation 29

8.10 Welding 30

8.11 Site compliance inspections 348.11.1 Risk of direct contact 348.11.2 Risk of indirect contact 398.11.3 Fit for purpose electrical equipment 41

9 LEGISLATION 56

9.1 Differences between mining and non mining electrical installations 56

9.2 Legislative models for electrical engineering safety 57

9.2.1 NSW non mining workplace 579.2.2 NSW coal mines 579.2.3 NSW metalliferous and extractive mines and quarries 589.2.4 Comparison of models 589.2.5 Standards of Engineering Practice 58

10 LIST OF APPENDICES 60

10.1 Appendix A: List of Figures 61

10.2 Appendix B: Electric Shock Statistics 64

10.3 Appendix C: Assessment Statistics 6810.3.1 Procedures 70

10.3.2 Equipment Inspections 7310.3.3 Knowledge of Electricity Workers 75

10.3.4 Enforcement Actions 75

10.4 Appendix D: Case Study 1 76

10.5 Appendix E: Case Study 2 79

10.6 Appendix F: Case Study 3 83

10.7 Appendix G: Extracts from AS3859 89

10.8 Appendix H: Extract from Coal Mines (General) Regulation 91

10.9 Appendix I: Extract from the General Rule 2000 9210.10 Appendix J: DMR assessment document 94

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2 Acknowledgments

The authors wish to acknowledge the following bodies whose support contributed to the

success of the project:

The management and field officers of the Department of Mineral Resources (DMR) whoassisted in conducting the assessments.

The mine managers and mine engineers whose high level of cooperation with the minesafety officers (MSOs) conducting the assessments contributed largely to the success of

the project.

The Hunter Industrial Electrical Safety Network (HIESN), a working group constitutedfor the sharing of safety information and learning. The authors wish to acknowledge

HIESN, and in particular member institutions BHP Billiton and Incitec, for their

willingness to share knowledge and experience and guidance documents such as the

Electric Shock Victim Management Protocols.

NSW Department of Mineral Resources Page 1


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3 Executive summary

The DMR identified an emerging problem of electric shocks at NSW mines and developed a

systematic program to identify the issues.

This program has shown that:

Industry performance is well below DMR expectations because a significant amount ofequipment is not fit for the purpose for which it is being used. This fitness for purposebegins at the design and carries on through installation and commissioning, operation,

maintenance, modification, decommissioning and finally disposal.

Some important procedures do not exist, some are not known to all people on site and, insome cases, are not complied with.

The training and skill levels of electricity workers have not kept up to date withcontemporary requirements.

Prevention of electric shock is based on multiple barriers being present. The project has

shown that these barriers to preventing electric shock are often absent. When all the barriers

are absent, the result is an electric shock. This absence of multiple barriers shows a failure ofmine management systems. This failure of management systems is shown by the fact that:

A number of mining operations have not identified electricity as a serious hazard

Good electrical engineering practice is not always a prime consideration

The number of non-conformances shows that a number of mines have not paid highregard to complying with legislation

The following section 3.1 summarises the recommendations made in respect to the electrical

safety of all workers at mining operations.

3.1 List of recommendations

3.1.1 Fit For Purpose equipment

All mines carry out a comprehensive AS/NZS 3000 and AS 3007

audit on all surface electrical installations. Rank any non-

conformances according to the risk and prepare a schedule for the

rectification work to be carried out over a reasonable time frame.

Particular attention should be paid to:

Refer Section 8.4

(p18)

Ensuring earthing requirements of AS/NZS 3000 and AS 3007are met

Refer Section 8.11.2(p40)

Targeting the risk of electric shock due to direct and indirectcontact

Refer Section 8.4

(p18)

Section 8.11.1 (p38)

Ensuring the tests detailed in AS/NZS 3000 Section 6 are carriedout on all electrical installations where required by AS/NZS

3000 and records of such tests are retained at the mine for future

reference

Refer Section 8.6

(p20)

Signs and notices at all electrical installations should be checked toensure that the requirements of the Coal Mines (General)

Regulations, AS/NZS 3000 and AS 3007 are complied with.

Refer Section8.11.3.2.4 (p50)



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Welding equipment must be in a fit for purpose state, and voltage

reduction device (VRD) units should be fitted to the output of

welding machines where the voltage is above extra low voltage.

Refer Section 8.10

(p34)

Consider the fitting of residual current devices (RCDs) to all lighting

circuits, socket outlets and control circuits to field devices that

operate at low voltage.

Refer Section 8.11.2.4

(p40)

Workers doing electrical work have access to suitable test equipment

that has an adequate safety rating.Refer Section 8.6.1

(p20)

Review the means for isolation that are present on site with due

regard to the risk to the operator while carrying out isolation.

Refer Section 8.9.1

(p29)

3.1.2 Competency of people doing electrical work and welding

All mines should detail requirements for the competency of

electricity workers on site. The requirements should contain those

competency elements that relate to all aspects of electricalengineering safety and standards compliance. In particular:

Refer Section 8.5

(p19)

Implement a structured training program aimed to refresh theskills of electricity workers in the area of AS/NZS 3000 and AS

3007 compliance

Refer Section 8.5.1

(p19)

People who do electrical work are sufficiently trained so thatthey are capable of determining the suitability of the instrument

for the circuit under test

Refer Section 8.6.1

(p20)

3.1.3 Procedures

Mines should develop and implement a procedure detailing the steps

necessary to ensure that all victims of electric shock are provided

with transport for professional medical assessment that includes a 12

lead ECG.

Refer Section 8.2 (16)

Mines should review procedures for the safe use and maintenance of

portable tools and leads. The procedures should consider the

adoption of the manufacturers safety directions, AS/NZS 3760 and

AS/NZS 3012, and make particular reference to requirements for

wet areas.

Refer Section 8.8

(p27)

Isolation procedures should contain detailed steps for testing for zero

energy.

Refer Section 8.9

(p29)

Mines should review their welding practices to ensure that they

comply with the requirements of AS 1674.2.Refer Section 8.10

(p34)



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3.1.4 Management systems

Mines should recognise electricity as a serious hazard. Refer Section 8.3

(p17)

Mines should implement engineering risk controls using a

management system approach consistent with AS 4081.

Refer Section 8.3

(p17)

Mines should reassess their maintenance strategy to ensure that it

covers standards compliance and pays particular attention to:

The identification of direct contact risk

The regular testing of earth continuity

Regular insulation resistance testing, and

A testing program aimed to ensure that electrical protectionsystems are set correctly and functional

Refer Section 8.7

(p24)

3.1.5 Legislation

Future revisions to mining regulations for both the coal and the

metalliferous and extractive sectors should:

Require the development, implementation and monitoring ofstandards of engineering practice and that a clear definition of

standards of engineering practice be developed to cover the life

cycle of the equipment

Require records of tests required by AS 3000 to be retained atthe mine

Refer Section 9.2.5

(p59)



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4 Abbreviations and definitions

The following abbreviations are used throughout this report.

4.1 Abbreviations

AS Australian Standard

CMRA Coal Mines Regulation Act 1982

DMR NSW Department of Mineral Resources

ESA Electricity Safety Act 1945

ESEIR Electricity Safety (Electrical Installations) Regulation 1998

GR2000 General Rule 2000

HBA Home Building Act 1989

HBR Home Building Regulations 1997

HIESN Hunter Industrial Electrical Safety Network

IEC International Electrotechnical Commission

IEE Inspector of Electrical Engineering - DMR

IP Ingress Protection rating

MIA Mines Inspection Act 1901

MSO Mine Safety Officer - DMR

OHSA Occupational Health and Safety Act 2000

OHSR Occupational Health and Safety Regulation 2001

PPE Personal Protective Equipment

RCD Residual Current Device (Safety Switch)

SEP Standards of Engineering Practice

SMP Safety Management Plan

SWP Safe Work Procedure

VRD Voltage Reduction Device

4.2 DefinitionsStandards of engineering practice

Standards of Engineering Practice (SEP) are prescribed for the coal mining industry in the

Coal Mines (General) Regulation 1999 (CMRA) and inferred in the General Rule 2000

(GR2000). There is no definition for SEP in legislation. For the purposes of this report the

following working description has been adopted.

A document or set of documents that set the minimum acceptable engineering

standards for all electrical equipment, activities and competencies at a mining

operation. It details the minimum acceptable criteria for the design, manufacture,

installation, commissioning, use, maintenance, modification, decommissioning anddisposal of electrical equipment.



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The term SEP is used throughout the document in both the legislative and generic sense.

Because the authors believe that SEPs are fundamental to achieving a structured approach to

electrical engineering safety there has been no distinction made in the way it has been applied

to either the coal or metalliferous and extractive mining sectors.

Pole filler

A device used for blanking off unused circuit breaker positions in distribution boards. Such

devices provide protection against direct contact by providing an ingress protection of IP2X.

Ingress protection

The level of physical protection afforded by a piece of electrical equipment. This is

concerned with protection against the inadvertent entry of personnel and the entry of water

and dust that may adversely affect the safe operation of the equipment. The levels of ingress

protection are detailed in AS 1939-1990Degrees of protection provided by enclosures for

electrical equipment (IP Code).



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5 Introduction

The mining industry has previously had a good record with regards to the number of

electrocutions, with the last death in the NSW mining industry occurring on 13 October 1992.

There have been 119 incidents of electric shock reported in the period 1 September 1999 to

30 June 2002, the period covered by the electric shock statistics in this report (eg Appendix

B). This number had risen to 153 by 30 March 2003. The number of reported electric shocksis at an unacceptable level and shows no indication of declining.

The DMR developed a program to assess and improve electrical engineering safety

performance in the NSW mining industry.

5.1 Electric shock

5.1.1 Effects of electric shock

The effects of electric shock are described in the Australian Standard: AS 3859-1991 Effectsof current passing through the human body (See Appendix G for extracts from AS 3859).

(Note: In late 2002, AS/NZS60479.1Effects of current on human beings and livestock

replaced this standard.)

It is generally known that the human body depends for its survival on oxygen being

transported to the brain. The lungs take oxygen into the blood that is pumped to the brain and

other parts of the body by the heart. Life will be under threat should the normal function of

either the heart or lungs be disrupted. The magnitude and the effect of an electric shock

depend on the current passing through the body. Relatively low levels of voltage and current

can be lethal. Voltages above 50V a.c. are considered lethal and currents as low as 20mA can

affect breathing and 50mA can affect the operation of the heart.(Note: a standard 100 Watt light globe has a current of approximately 400 milliamps (mA)

flowing through it.)

5.1.2 Types of electric shock

AS/NZS 3000 describes types of electric shock and the methods that may be used to prevent

them occurring.

5.1.2.1 Direct contact

AS/NZS 3000 defines direct contact as contact with a conductor or conductive part that is

live in normal service. It further requires that persons and livestock be protected againstelectric shock by direct contact. The methods that may be employed in the prevention of

direct contact are:

Insulation: by completely covering the live parts with an insulating material

Barriers and enclosures: by placing live parts inside enclosures designed to protect againstinadvertent contact with live parts. The level of protection that is required is an ingress

protection rating of IP2X as defined in AS 1939

Obstacles: these shall prevent unintentional approach to the live parts and unintentionalcontact with live parts in normal service

Placing out of reach: by placing accessible parts at different voltages out of arms reach



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5.1.2.2 Indirect contact

AS/NZS 3000 defines indirect contact as contact with a conductive part which is not

normally live but has become live under fault conditions (due to insulation failure or some

other cause). AS/NZS 3000 requires that persons and livestock be protected against the

dangers arising from indirect contact. The methods of prevention against indirect contact are:

Automatic disconnection of supply: by automatically disconnecting the supply on the

occurrence of a fault between live parts and exposed conductive parts or a protectiveearthing conductor

Use of Class II equipment: by the use of appliances and other equipment that do not relyonly on basic insulation for safety

Electrical separation: by the use of supply that is derived from an isolating transformercomplying with AS 3108

5.1.3 Causes of shock

The statistics relating to the incidence of electric shock are contained in Appendix B. The

data shows that the majority of shocks have occurred on the surface areas of mines on fixed

equipment operating at low voltage. It further shows that 62% of shocks were categorised as

being indirect and that in 73% of cases the victim was not an electrical worker. This

information leads to the conclusion that the equipment was not fit for the purpose for which it

was being used. This is further identified in that for 75% of cases not fit for purpose was

identified as the primary cause of the incident.

The fitness for purpose of electrical equipment begins at the design stage and covers the

installation and commissioning, use, maintenance, overhaul and repair, modification,

decommissioning and finally disposal. In any of these stages, the safety of people must not be

compromised by exposure to the risk of electric shock.

In order to achieve fitness for purpose at all stages of the life cycle of electrical equipment,

the people who undertake the tasks associated with each stage must be suitably competent to

carry out those tasks. In the area of compliance with legislation and standards it is vital that

the people who are responsible for achieving compliance are suitably trained in the

requirements of the standards.

5.2 Assessment project

John Waudby, Senior Inspector of Electrical Engineering, NSW Department of Mineral

Resources, initiated this project to investigate the state of electrical installations, current

practices and procedures that mining operations have in place to manage the risk of electric

shock.

The project focussed on, but was not limited to, compliance with the applicable mining

legislation. Compliance with AS/NZS 3000 and AS 3007 is required by the relevant

legislation for both the coal, and metalliferous and extractive sectors of the industry.

Compliance with other Australian Standards was assessed due to their particular relevance in

the mining industry.

This report makes recommendations that are necessary to improve the electrical engineering

safety and reduce the incidence of electric shock throughout the mining industry.



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5.2.1 Terms of reference

Analyse available data on electric shock incidence in the NSW mining industry.

Prepare an assessment document for use during site inspections aimed at identifyingissues that have an impact on the risk of electric shock.

Carry out an assessment on the surface of NSW mining operations to give the DMR anoverview of the management of electrical technology and the state of installations in

relation to issues that have an impact on the incidence of electric shock.

Carry out inspections at all coal operations and a selection of metal mines and quarryingoperations.

Supply operations inspected with a report detailing findings of the inspection.

Construct a database to hold the results of the inspections.

Review legislation for appropriateness.

Make recommendations to reduce the risk of electric shock in the NSW mining industry.

Communicate the findings of the project to the mining industry and other interestedbodies.

5.2.2 The project team

Project manager: Steve Millington, IEE, DMR

Team members: Paul Lackey, MSO (Electrical), DMR

John Weaver, MSO (Electrical), DMR



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6 Background and context

6.1 Electrical inspectors

The DMR employs Inspectors of Electrical Engineering (IEE) as inspectors under the Coal

Mines Regulation Act 1982 and theMines Inspection Act 1901.

The function of an IEE is to assess the safety of electrical installations and practices at mines,and to implement enforcement responses where required. IEE carry out assessments and

incident investigations at mines and processing plants. IEE are also involved in apparatus

approval, workshop approval and workshop auditing functions. IEE are involved in the

setting of standards and are active participants in the preparation of Australian Standards,

International Electrotechnical Commission (IEC) standards and MDG guidelines. Due to this

involvement, IEE are ideally positioned to observe the effectiveness of contemporary

electrical engineering safety legislation and standards, and make comparisons of safety

performance against other mining and non mining legislative regimes.

IEE are able to observe and draw comparisons about electrical engineering safety

performance in the non work place, residential installation arena. In addition the IEE havedetailed knowledge of the difficulties confronted in applying existing electrical legislative

requirements.

6.2 Philosophy of operation

Figure 1. Nertney Wheel

The Nertney Wheel.

The basis of this as a model is that in order to have a safesystem, key elements must be present.

These elements are that the system must contain appropriateSafe Working Procedures, using fit for purpose equipment thatis installed and maintained by competent people within a Safe

Working Environment.

The IEE have adopted the Nertney Wheel as a fundamental element of their philosophy of

operation", showing how the IEE consider electrical engineering safety. The philosophy ofoperation is:

Based on risk management

Requiring fit for purpose equipment

Using competent people and processes/procedures

All supported by management systems

Applies throughout the life cycle of the mine

Ownership of safety rests with the mine owners/operators and equipmentmanufacturers/suppliers

The way IEE do things must contribute to changing the safety culture of the industry sothat industry accepts ownership of safety

Anything IEE do must provide for a level of risk less than or equal to the current risk Information is provided in advisory terms, not as a must do it this way, but be prepared

to take appropriate actions against stakeholders not complying with safety legislation



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6.3 Electrical engineering safety

Electrical engineering safety encompasses:

Prevention of electric shock and burns, (electrocution, death or injury as a result of ashock, radiation burns, flash burns, burning particles and plasma)

Prevention of electrical arcing and surface temperatures that have sufficient energy toignite gas and/or dust

Prevention of fires caused by the malfunction of electrical equipment, and

Prevention of injury and death from unintended operation due to a failure to stop, or afailure to operate, of electrically powered and electrically controlled equipment



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7 Methodology

In response to the frequency of reported electric shocks in the NSW mining industry, the

DMR researched all available statistics on electric shock in the industry. This information

showed a recurring pattern of electric shock incidence. A decision was made to conduct an

assessment of the systems that mining operations have in place to manage the risk of electric

shock.

The statistics revealed that the majority of incidents had occurred at surface mines and

quarries and the surface areas of underground mines. Only 21% of the incidents occurred in

the underground workings of mines.

The objective was to conduct the assessment of the surface areas of all coal operations,

including mines and preparation plants, and a number of larger metal mines and quarries. The

project was to assess the sites for compliance with the legislation and standards, and to

ascertain the level of residual risk present on site.

An assessment document was produced to assist in the process and to gather information

about the industry as a whole (Refer to Appendix J). Its function was to investigate how the

industry manages the issues that relate to electrical engineering safety. This documentcovered the areas that were deemed to be a high risk, either due to the historical record of

electric shock, or due to the nature and function of the equipment itself.

A selected number of sites were selected for follow up visits in order to determine whether

there had been an improvement since the initial visit.

The assessment process was designed to examine the procedural aspects of the management

of electrical safety and to conduct an inspection of a selection of electrical equipment that is

common to most mine sites. The equipment inspected was considered to be high risk, either

due to the number of reported electric shocks or the nature of the equipment itself.

7.1 Referenced documents

This project considered the requirements of the following standards, regulations and codes

when conducting the assessments:

NSW Coal Mines Regulation Act 1982

Coal Mines (General) Regulations 1999

Coal Mines (Open Cut) Regulations 1999

Coal Mines (Underground) Regulations 1999

NSW Mines Inspection Act 1901

General Rule 2000

Mines Inspection Regulation 1999

AS/NZS 3000-2000: Electrical Installations (Also known as Wiring Rules)

AS 3007.1-1987 : Electrical Installations - Surface Mines and Associated ProcessingPlant- Scope and Definitions

AS 3007.2-1987 : Electrical Installations Surface Mines and Associated ProcessingPlants General Protection Requirements

AS 3007.3-1987 : Electrical Installations Surface Mines and Associated ProcessingPlants General Requirements for electrical equipment and ancillaries

AS 3007.4-1987 : Electrical Installations Surface Mines and Associated ProcessingPlants Additional Requirements for Specific Applications



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AS 3007.5-1987 : Electrical Installations Surface Mines and Associated ProcessingPlants Operating Requirements

AS 1674.2-1990: Safety in Welding and Allied Processes - Electrical

AS 1966.1-1985: Electric Arc Welding Power Sources - Transformer Type

AS 1966.2-1985: Electric Arc Welding Power Sources - Rotary Type

AS/NZS 3760-2001: In Service Safety Inspection and Testing of Electrical Equipment AS/NZS 3012-1995: Electrical Installations Construction and Demolition Sites

AS 3859-1991: Effects of Current Passing Through the Human Body

AS/NZS 4836:2001 Safe Working on Low Voltage Electrical Installations

The following items (7.2 to 7.11) were covered in the assessment process.

7.2 Electric shock victim management procedure

The existence of a procedure and whether it contained all necessary aspects of victimmanagement

The level at which the procedure was known and understood by all workers on site

7.3 Management of electrical engineering safety

7.3.1 Risk management

The recognition of electricity as a serious hazard

The existence of a SEP to manage the hazards associated with the safe use of electricity

The greatest risk of electric shock on site as determined by the mine personnel

7.3.2 Ownership of electrical work

The organisational structure of the mine with respect to how the electrical workers arecontrolled

7.4 AS 3000 and AS 3007 audits

Whether an audit of the surface areas of the mine for standards compliance has beenconducted

The person or organisation that conducted the audit if one had been carried out

How comprehensive the audit had been and whether it covered every circuit on thesurface of the mine

7.5 Competence

Whether the operation has competency standards for electrical workers

Whether the workers on site meet these standards

The training that electrical workers have received in AS/NZS 3000 and AS 3007

Whether the workers on site have been trained to use the mines SEPs



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7.6 Commissioning and testing

Whether the electrical personnel carry out the tests detailed in AS/NZS 3000 Section 6

How the tests are recorded

The commissioning procedure used by the operation

The testing that is carried out on site

The test equipment used by electrical workers

Whether every electrician has access to suitable test equipment and whether the employerprovides it

How electrical workers test for zero energy when carrying out isolation of electricalequipment

7.7 Electrical maintenance

The manner in which maintenance is carried out

Who carries out the maintenance Whether the maintenance strategy has provisions to ensure the ongoing compliance with

AS/NZS 3000 and AS 3007

The existence and content of Standards of Electrical Engineering Practice (SEPs) relatingto the maintenance of electrical equipment

Whether the site SEPs meet the requirements of CMRA Regulations and GR2000

Whether there is evidence of the application of relevant standards

Whether the electrical workers have knowledge of, and use of, these standards

7.8 Portable apparatus The existence of a SEP for the safe use and maintenance of portable electrical apparatus

The application of AS/NZS 3760 on site

Whether a testing, inspection and tagging program for portable electrical apparatus andleads is in place

Whether there are special provisions for use the use of portable tools and leads in wetlocations

7.9 Isolation

Whether the mine has documented isolation procedures

Whether the operation has a documented Test Before You Touch procedure

Whether the operation uses a lockout system of isolation

Whether procedures exist for the Removal and Restoration of power

7.10Welding

Whether the operation has a documented procedure for the safe use and maintenance ofwelding equipment

Whether the mine has taken the requirements of AS 1674.2, AS 1966.1 and AS 1966.2

into consideration in determining safe welding procedures

Whether basic welding safety practices are followed

Whether the use of VRDs is practised on site



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7.11Site compliance inspections

The equipment inspection section of the assessment was conducted with focus on the

following areas:

Main switch yard / substation area

Conveyor installation

Three electrical enclosures / switch rooms

General preparation plant areas

Workshops

General electrical installations

Mains fed mobile equipment

7.12Process

Two additional MSOs were appointed to enable the project to be completed in a reasonable

time frame. The MSOs were stationed where they could best access a majority of the mines.An Electrical Inspector was nominated to manage and coordinate the project.

On completion of each inspection and assessment of a mining operation or declared plant a

report was prepared and a copy sent to the operation for information.

A purpose-designed database was used to analyse the information gathered by the

assessments to highlight common problems that require attention.

7.13Actions

Every mine has been forwarded an individual report.In some cases improvement notices were issued.

Where installations were considered unsafe they were rectified immediately, turned off or

temporary barriers installed.

Presentations have been conducted for several industry committees about the project

including:

Internal DMR field officers

Check Inspectors Conference

Hunter Industrial Electrical Safety Network (HIESN)

Mine Safety Advisory Council (MSAC)

Electricity Industry Safety Advisory Council (EISAC)

Mine Electrical Engineers Meetings

Mine Electrical Engineering Safety Conference

Mine Safety Conference (Terrigal)

Articles published in the Mine Safety Update (a DMR publication)

The assessment documents are part of the assessment files for each mine and will be used as

reference material for future assessments by DMR field officers.



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8 Findings and recommendations

8.1 Role of electricity in mining

We must acknowledge the importance of the supply of electricity and the contribution it

makes to our daily lives. It plays an important role in the mining industry by the provision of

energy for the mining and processing of various minerals and ores. However, it is also a

ubiquitous hazard and a major cause of accidental deaths and injury within the Australian

community.

To minimise this hazard the mining industry must comply with legislation, regulations,

standards, codes of practice, electrical industry safety guides, installation procedures, safe

working procedures, safety tag and lock-out procedures, testing procedures and testing

procedures for installations, etc. Where the legislation, regulations, standards, codes, guides

and procedures are not followed incidences of electric shock are likely to occur.

8.2 Procedure for the management of victims of electric shock

If a person suffers an electric shock it is vital that prompt action is taken in order to increase

the chance of recovery. The effects of electric shock cannot be easily determined by normal

first aid and only medical practitioners have the knowledge and equipment available to

properly treat victims of electric shock. The effects of electricity on the human body are

detailed in AS3859-1991:Effects of current passing through the human body (refer Appendix

G).

The manner in which a mine manages a victim of electric shock is best detailed in a

procedure that is conveyed to all people on site. It was expected that all operations would

have a procedure that covered the care of a victim from the time the shock was received

through to their return to work.

A significant number of electrical workers and mine managers were not aware of the need to

seek medical assessment for all victims of electric shock. The assessment process revealed

that 76% of sites indicated that they would send all victims of electric shock for professional

medical assessment and 61% of mining operations had this detailed in a formal procedure. In

many of those cases the existence and content of the formal procedure was not well known.

61% of Mines have documented victimmanagement procedures.

76% of Mines would refer all victims ofelectric shock to hospital.

0 2 0 4 0 6 0 8 0 10 0

Figure 2. Victim management statistics

50% of Mines have procedures thatrequire an ECG.

Recommendation 1. All mining operations should have a procedure

detailing the steps necessary to ensure that all victims of electric shock areprovided with transport for professional medical assessment that includes a12 lead ECG. The procedure should be known to all workers, including

contractors.



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8.3 Management of electrical engineering safety

8.3.1 Risk management

The assessment project revealed that only 58% of sites had formally recognised electricity as

a serious hazard. The sites that had considered the hazard had not sufficiently addressed the

risk in either the SEP or the SMP in place at the mine.The assessment process included an identification of the greatest risk of electric shock on site

in the opinion of either the manager of the operation or the electrical engineer, depending on

the site.

The most common risks identified by the mine personnel were:

Use of portable electric tools

Welding

Welding in wet locations

Contractors working generally

The identification of the above items as the greatest risk on site did not always lead to those

risks being properly managed.

Very few operations considered the poor state of equipment or installations as their greatest

risk of electrical shock, although some sites had major equipment and installation upgrades

planned. The statistics clearly show that a lack of fitness for purpose was a factor in 75% of

the reported electric shocks.

8.3.2 Ownership of electrical engineering safety

It is difficult to quantify the effect that a particular management structure has on electrical

engineering safety. However, all operations require a level of engineering presence to ensurethat compliance with legislation and standards is maintained. An important element is that the

ownership of electrical engineering safety is vested in a person at the mine. The attributes of

ownership are that it must be identified, agreed and resourced.

At the mines that were assessed as very secure these attributes were strongly evident.

Conversely at the mines assessed as very exposed there was little evidence of ownership.

Ownership can take many forms depending on the nature of the operation, eg coal mine

electrical engineer, or contract electrician at a quarry. It can range from a permanent member

of the management team to a person under a contract or consultant arrangement.

Recommendation 2. Mines should recognise electricity as a serioushazard and identify and implement risk controls in accordance with AS4081.

8.4 AS/NZS 3000 and AS 3007 audits

Legislation requires that all surface mines and the surface areas of underground mines

comply with AS/NZS 3000 and AS 3007. These two standards detail the general

requirements for electrical safety and contain measures for the prevention of electric shock to

both persons and livestock.

It has not been uncommon for inspectors to find that electrical installations are below an

expected standard when carrying out inspections. Previously, inspectors have made

suggestions that all operations should have their electrical installations audited for



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compliance with AS/NZS 3000 and AS 3007, and have systems in place to ensure ongoing

compliance.

A number of operations have responded and carried out such audits. In some cases, a

structured audit revealed that there were in excess of 2000 non-compliances on a single site.

58% of Mines have conducted audits for compliancewith standards.

0 2 0 4 0 6 0 8 0 10 0

Figure 3. Audit statistics

26% of Mines have conducted audits that cover allcircuits on surface.

This project revealed that only 58% of mining operations had carried out AS/NZS 3000 and

AS 3007 audits, with only half of these being comprehensive audits. A sample inspection ofselected electrical equipment is not sufficient when determining safety compliance. An audit

of this type needs to cover every electrical circuit on site.

Of the operations that have carried out audits, many have non-conformances that require

attention. In the worst cases the audits had been carried out over two years previously and

non-conformances were still outstanding.

Recommendation 3. All operations carry out a comprehensive AS/NZS3000 and AS 3007 audit on all surface electrical installations. This shouldspecifically target risk of electric shock due to direct and indirect contact.

Rank any non-conformances according to the risk and prepare a schedule forthe rectification work to be carried out over a reasonable time frame.

8.5 Competency standards

The Coal Mines (General) Regulation 1999 Clause 9 requires that all coal mines and declared

plants establish standards of engineering practice. Clause 9 (3) (a) requires that the SEP

contain provisions for competency for working on relevant equipment. The General Rule

2000 Clause 12 (6) requires all persons at the mine have the necessary skills and competence

for the tasks that they are to undertake.

In order to achieve fitness for purpose at all stages of the life cycle of electrical equipment,

the persons who undertake the tasks associated with each stage must be suitably competent to

carry out those tasks.

At 74% of the operations assessed, there were some forms of competency provisions. The

detail of these competency provisions differed markedly from site to site.

Of the sites that do have provisions for competency in the SEP very few have criteria for

what requirements are necessary to achieve that competency. There are very few of the SEP

competency provisions that require an electrical worker of the mine to be licensed.



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The Coal Mines (General) Regulations 1999 Clause 28(2) requires all coal mines and

declared plants to comply with AS/NZS 3000. The General Rule 2000 Clause 68 (1)(c)(ii)

requires all metal mines and quarries to comply with AS/NZS 3000.

Recommendation 6.All mining operations adopt a policy where the testsdetailed in AS/NZS 3000 Section 6 are carried out on all electricalinstallations where required by AS/NZS 3000 and records of such tests are

retained at the mine for future reference.

8.6.1 Test equipment

In order to prevent electric shock and arc blast injuries when using test equipment for the

purposes of testing for dead or other reasons, it is vital that electricity workers have access to

suitable test equipment. For test equipment to be suitable for use it must have an appropriate

safety rating and be suitable for the circuit under test.

Non contact detectors are used to detect the presence of electricity without actuallycontacting the live parts. They can be particularly useful when determining if there are

unwanted voltages present in an enclosure after isolation as part of a test before touch

process.

Electricity workers need to know how to determine the suitability of test equipment for the

circuit under test. Only 29% of electricity workers understood the fault level limitations of

the multimeters they were supplied with.

Recommendation 7.All operations ensure that electricity workers haveaccess to suitable test equipment having a suitable safety rating and thatelectricity workers be sufficiently trained so that they are capable of

determining the suitability of the instrument for the circuit under test.



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8.7 Maintenance

Essential to the ongoing compliance to standards and legislation is the maintenance that is

carried out on electrical equipment.

The General Rule 2000 Clause 68 (1)(b) requires that suitable inspection and testing of

electrical installations at the mine is carried out at the time of installation and then

periodically in order to identify any deficiencies and have them corrected.

The Coal Mines Regulation Act 1982 section 103 for mines and section 145 (i) for declared

plants requires all sites to have a system for the inspection and testing of electrical equipment.

In most cases compliance with AS/NZS 3000 and AS 3007 issues were not well covered in

the maintenance strategy. Those mines that did attempt to cover compliance were very

general in the inspections that were required and rarely did maintenance inspection sheets

cover basic requirements such as risk of direct contact. Many mines do not have specific

equipment checks as part of a maintenance scheme but rather do maintenance on an as

needed basis. The number of non compliances identified during the course of this projectattests to the fact that standards compliance has significant room for improvement.

Figure 4. Socket outlet held in place with tape

Ineffective temporary repairs have been madeto the socket outlet.

The outlet has been held to the mounting blockwith tape.

The tape has since let go allowing the 240 Vsocket outlet to fall away from the base thusexposing the conductors.

This exposes workers to a risk of direct contactwith the exposed live conductors.



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Essential to the prevention of electric shock by indirect contact is that the protection system is

designed and set according to the application. The elements of the protection system should

be regularly checked to ensure correct operation under a fault condition. The assessment

found that deficiencies existed with the protection of the final subcircuits.

The Coal Mines (General) Regulation 1999 Clause 28 (2) requires that all mines and declared

plants comply with AS 3007. The General Rule 2000 Clause 68 (1)(c) requires all metal

mines and quarries to comply with AS 3007. AS 3007.2 details the requirements for

protection systems at mining sites.

One essential element of a protection system is the integrity of the earthing. If the earthing is

not present or it is inadequate then the protection system is unlikely to operate in case of

fault. Periodic testing for the safety of the electrical installations is not common with only

44% of sites carrying out regular earth continuity testing.

Figure 5. Disconnected earth conductors in electrical panel

Earth conductors which have been leftdisconnected means that there may be someequipment in the field that is no longer earthed.

Maintenance strategies should include earthcontinuity testing protocols that will detectunearthed equipment.

Unearthed equipment may cause protectionsystems to be ineffective and increase the risk ofshock due to indirect contact.

0 2 0 4 0 6 0 8 0 10 0

Figure 6. Percentage of mine that conduct EC testing

44% of Mines conduct regular earth continuitytesting of electrical equipment



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In circuits protected by RCD units the testing of these units to ensure correct function is

essential. The testing requirements and frequency of such tests is detailed in AS/NZS 3760.

Very few of the maintenance schemes in place make reference to this standard and only 44%

of mines carry out the injection tests of RCD units as required by AS/NZS 3760.

0 2 0 4 0 6 0 8 0 10 0

Figure 9. Percentage of mines that injection test RCD units

44% of Mines test RCD unit functionality usinginjection test methods.

Recommendation 8.All mines should reassess their maintenance strategy toensure that it covers standards compliance. The maintenance scheme should

have specific requirements for:

The identification of direct contact risk Regular testing of earth continuity

Regular insulation resistance testing, and a

Testing program aimed to ensure that electrical protection systems are setcorrectly and functional.

Figure 10. Well designed distribution board

Maintenance has been considered in the design of the distribution board.

The socket outlets on the right side of the distribution board have beeninstalled for the sole purpose of injection testing RCD units.

8.8 Portable Electrical Apparatus

Portable electrical apparatus includes portable hand tools, hand lamps, extension cords,portable welders, mains powered measuring equipment, portable heaters, etc. These are all

items of electrical equipment that are held while being used in their normal function and they

account for 19% of the total electric shocks reported.



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The assessment project examined all aspects relating to the safe use and maintenance of

portable tools and leads and revealed that the management of portable tools and leads has

significant deficiencies.

Most sites have considered the maintenance of portable tools and leads in the mine

maintenance strategy. AS/NZS 3760 describes the type and frequency of tests required to be

performed on all portable tools to ensure safety.

The type of environment that is present on mine sites and preparation plants is particularly

harsh. AS/NZS 3012 details the precautions necessary for the safe use in environments such

as this. There have been a number of safety alerts advising mine sites to consider the

recommendations of AS/NZS 3012 when using portable tools and leads on site.

The use of portable tools, in particular Class II equipment, can be particularly hazardous if

they are operated in a damp environment and pose a risk of serious electric shock due to the

fact that no protective conductor is present in the tool. Manufacturers of portable tools

usually draw attention to these hazards in their recommendations for safe use.

There was a general lack of acknowledgment of the manufacturers safety directions with

most operators not knowing what these recommendations were, or even having access to the

documentation that is supplied with the tools by the manufacturer.

23% of Mines consider wet areas in the procedures

79% of Mines cover contractor's equipment in their procedures

25% of Mines consider manufacturers safety directions in theirprocedures

10% of Mines consider AS 3012 in their procedures

25% of Mines include steam cleaners, sump pumps etc. in theirportable apparatus scheme

74% of Mines include leads in scheme

78% of Mines include tools in scheme

73% of Mines maintain portable apparatus according to AS3760

32% of Mines consider suitability of equipment in their portableapparatus scheme

0 2 0 4 0 6 0 8 0 10 0

Figure 11. Portable tool statistics

57% of Mines have a documented procedure



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Inspections of the portable tools and leads on site revealed that much of the equipment was

not in a fit state to remain in service.

The typical non-conformances observed were:

No evidence of inspections having been carried out

Inspections out of date

Equipment that had visible damage that was still in service

Equipment being used in unsuitable locations

Equipment not fit for the purpose for which it was being used

There is an onus of responsibility on all workers to visually check the equipment prior to use

to make sure that the equipment has a valid inspection tag and that the equipment is not

damaged.

Figure 12. Portable lead with conductors showing

A lead with the conductors showing at the

back of the plug. It was still in service at thetime of inspection.

Figure 13. Lead with current tag that is not serviceable

A damaged lead with a recent inspection tagattached.

The lead was not in a serviceable condition,as the lead was not properly restrained in theplug top.



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Figure 14. Lead with conductors showing

A lead with the conductors clearly visible at theback of the plug.

Figure 15. Portable welder with damaged case

A welder with a badly damaged case.

The practice of repairing the damage using duct tapeis not a suitable means of repair.

The equipment was still in service and was clearly notfit for purpose.

Recommendation 9. All mines and preparation plants should revise theirprocedures for the safe use and maintenance of portable tools and leads. Thescheme should consider the adoption of the manufacturers safety directions,

AS/NZS 3760 and AS/NZS 3012. It should make particular reference torequirements for wet areas.



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8.9 Isolation

Isolation procedures form an important part in the prevention of electric shock to persons

working on electrical equipment.

When electricity workers are required to work on electrical equipment the Coal Mines(General) Regulation Clauses 27 and 33 require an operation have an isolation procedure to

ensure that conductors are not energised, and that steps are taken to ensure that this will

remain so while work is carried out.

The General Rule 2000 Clause 73(a)(iii) requires that the power supply to equipment be

isolated prior to work being carried out and steps taken to ensure that it cannot be

reconnected accidentally.

Most sites had some form of isolation procedure with 85% having this documented in some

format. It was most common for this to be contained in either the SEP in the case of coal

operations, or in the SMP in metal mines and quarries. In some of the smaller operationsisolation and tagging were contained in the induction documentation only.

There is a trend toward a lockout philosophy for isolation equipment in lieu of tagging alone.

This trend is such that 44% of operations use locks in all or part of the site isolation

procedures whereas 41% still use tags alone in their isolation.

An essential part of isolation procedures is a test before you touch protocol. This is a

critical test where electrical workers are required to work on electrical conductors in order to

prove that correct isolation has been effected. Many isolation procedures require electrical

workers to carry this out but do not specify the test method. The method for conducting a

test before you touch action should be documented.

Documented test before touch procedures were not readily available at most sites.

Recommendation 10. Isolation procedures should contain detailedsteps for testing for zero energy.



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8.9.1 Internal isolation

Isolation devices should be readily accessible without exposing the operator to live parts.

Figure 16. Circuit breakers for isolation

The circuit breakers are located inside anelectrical enclosure that has to be opened to

effect isolation of electrical equipment.

The location of the equipment means theoperator is exposed to an increased risk of injurydue to arc blast.

It is also foreseeable that due to the nature ofoperation of the circuit breaker toggles, a slip bythe operator would result in a serious directcontact shock.

Recommendation 11. Mining operations should review the means forisolation that are present on site with due regard to the risk to the operatorwhile carrying out isolation.



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8.10Welding

The use of welding equipment is responsible for 9% of the total electric shocks reported. In

some cases the contributing factor was the fitness for purpose of the equipment and in other

cases it was the manner in which is was being used.

Welding operations need to be conducted with due regard to the safety of the welder and

other persons who may be in the vicinity and the potential adverse impact on other electrical

installations. This is best detailed in a procedure for safe welding. This procedure should

detail the precautions necessary for the prevention of electric shock to the operator and others

and also consider the design and installation of the equipment.

Figure 17. Unattended electrode holder

An electrode holder is left unattended.

This is poor practice as it increases the risk ofelectric shock to either the welder or other

workers in the area, due to an inadvertentcontact with the electrode and the work bench.

The assessment of procedures and equipment as part of this project revealed that the

procedures were not sufficiently detailed and that the quality of the welding equipment was

generally poor and that a number of deficiencies exist.

Only 51% of operations have any form of documented safe welding procedure at all and only

14% consider the design of the welding equipment in that procedure.

Only 43% of sites adopted safe welding practices and only 39% of sites had adopted AS1674.2 as a basis for safe welding practices.

To ensure that the welding equipment remains in a serviceable condition it is necessary to

periodically test that the equipment is safe. AS 1674.2 details the tests necessary and the

recommended frequency of those tests. In 66% of cases the mine carries out these tests at the

required intervals.

The continued use of damaged equipment increases the risk of electric shock to the user. At

47% of sites the welding equipment that was in use was damaged in some way. This damage

ranged from cracked electrode holders up to the case of the welder being damaged such that it

had been held together with tape.



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Figure 18. Damaged electrode holder

This handpiece is damaged and should bereplaced.

Figure 19. Damaged connections

The connections to the welder have been

replaced but the original defective connectionshave been left connected to the terminal.



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Figure 20. Damaged supply cable

The power lead of the welding machine has suffered insulation damageand has been repaired with PVC tape.

A common practice within the industry is to locate the welding machine in a convenient

position and reticulate the welding leads throughout the building as necessary. In 13% of

these cases the return lead of the welder is permanently connected to the building frame. This

practice is not consistent with the requirements of AS 1674.2 and can seriously affect the safe

earthing of other electrical equipment in the building.

Figure 21. Return lead connected to building

The return lead of the welding machine is permanently connected to thebuilding frame.

This practice is not consistent with the requirements of AS1647.2 and hasthe risk of adversely affecting the safe earthing of electrical equipment.



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The output circuit of welding equipment is sufficient to inflict a serious shock. The DMR has

released safety alerts in the past recommending the use of VRDs as a means of limiting the

open circuit voltage of a welding machine to a safe level. The adoption of VRDs to welding

equipment has been adopted at 60% of mine sites but at most sites the function of the VRD is

not tested.

Figure 22. Well fitted out welding machine

A well fitted out welding machine.

The environment in which the welder will be operating has beenconsidered. The welder is located inside a stainless steel enclosure andthe unit is well elevated to prevent water ingress from washing downactivities.

The VRD is visible at the top of the unit.

The presence of water when welding operations are being carried out greatly increases the

risk of electric shock.

Figure 23. Welding in damp areas

These workers are standing in water whilecarrying out welding operations.

This practice greatly increases the risk ofelectric shock to both the welder and theassistant.

AS1674.2 details precautions to be taken when

welding in damp locations.



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49% of Mines have safe welding procedures

39% of Mines comply with AS 1674.2

14% of Mines consider AS1966.1

14% of Mines consider AS1966.2

66% of Mines test welding equipment every 3 months

8% of Mines overhaul welding equipment every 2 years

65% of Mines require the use of VRDs

25% of Mines test VRD units

43% of Mines apply basic welding practices

0 2 0 4 0 6 0 8 0 10 0

Figure 24. Welding statistics

Recommendation 12. All mines should review their welding practicesto ensure that they comply with the requirements of AS 1674.2. Theyshould also require the use of equipment that is in a fit for purposestate, and VRD units should be fitted to the output of welding machineswhere the voltage is above extra low voltage.

8.11Site compliance inspections

8.11.1 Risk of direct contact

The risk of electric shock by direct contact is very serious. It was found during the

assessment project that 62% of mining operations had an identifiable risk of direct contact

somewhere on the site. AS/NZS 3000 defines direct contact as contact with a conductor or

conductive part that is live in normal service.

Preventive measures against direct contact are defined in AS/NZS 3000 as:

Insulation

Barriers or enclosures

Obstacles Placing out of reach



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8.11.1.1 Enclosure locking

AS 3000 requires that live parts be inside enclosures or behind barriers that provide a degree

of protection of at least IP2X as defined in AS1939. 17% of all the enclosures inspected had a

risk of direct contact due to the enclosure not being locked when live parts are exposed.

Figure 25. Enclosure that is not normally locked

This enclosure is not normally locked.

The terminals inside are live in normal serviceand represent a significant risk of electric shockdue to direct contact.

There were no signs warning of the presence oflive parts.

Figure 26. Enclosure with exposed live terminals

This enclosure is not normally locked.

Live parts are readily accessible when the enclosure is opened.

This presents an increased risk of electric shock due to direct contact withlive conductors.

It also increases the risk of injury to persons who open the enclosurewhilst it is in operation due to arc blast when the switchgear is operating.



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8.11.1.2 Internal control functions

Enclosures that have internal reset or control functions that are located in the vicinity of live

parts present an increased risk of direct contact due to the frequency of exposure to the hazard

by the person operating the equipment. It was found that 26% of enclosures have some form of

internal control function.

Figure 27. Enclosure with internal start function

It is necessary to open this enclosure to start the drive.

Note that the start pushbutton is located inside near unshroudedterminals located within the enclosure and on the door.



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8.11.1.3 Missing pole fillers

Pole fillers are used to blank off unused circuit breaker positions in distribution boards. When

these are not in place there is a risk of electric shock due to direct contact. The risk of electric

shock when these pole fillers are not fitted is high due to the action of operating the circuit

breakers, and the close proximity of an operators finger to the live parts when operatingadjacent circuit breakers. The inspection of enclosures on site revealed that pole fillers were

missing from 20% of enclosures that required them.

Figure 28. Distribution board with missing pole fillers

The distribution board has missing pole fillers.

Figure 29. Distribution board constructed on site

This distribution board has been manufacturedin situ. The positions where there are no circuit

breakers fitted are not blanked off and live partsare easily accessible.



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Figure 30. Distribution board with missing pole fillers

Missing pole fillers allow inadvertent contact withelectrical terminals through the opening. Itpresents a high risk due to the action ofoperating the circuit breakers.

Figure 31. Distribution board with several pole fillers

missing

An area of the distribution board has several pole fillers missing. Thelive parts are visible and an electric shock in this instance isforeseeable.

Recommendation 13. Mine sites should undertake an audit process toidentify risks of direct contact, have them rectified and include provisions

for identification of these issues in the mine maintenance scheme.



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8.11.2 Risk of indirect contact

AS/NZS 3000 defines electric shock due to indirect contact as contact with a conductive part

that is not normally live but becomes live under fault conditions (due to insulation failure or

some other cause). Preventive measures against indirect contact are:

Automatic disconnection of supply

Use of Class II equipment

Electrical Separation

8.11.2.1 Earth bonds

When an electrical enclosure has equipment mounted on the door, there must be an earth

bond from the enclosure to the door. This is to prevent a difference of potential between the

door and the enclosure in the case of a fault occurring. Inspections revealed that earth bonds

were missing from 8% of enclosures that had electrical equipment mounted on the door.

Figure 32. Enclosure door with earth bond not connected

The earth bond has been left off this door. Thereis a risk of electric shock due to indirect contactdue to a possible difference of potential between

the enclosure and the door should a fault occur.

8.11.2.2 Disconnected earths

One form of protection against indirect contact is the automatic disconnection of the supply

in case of a fault occurring between live parts and earth. In order for this protection to be

effective all conductive parts of the installation must be effectively earthed.

Figure 33. Disconnected earth conductors

The earth conductors have been leftdisconnected. This means that there may besome equipment in the field that is no longerearthed. When equipment is not earthed there isa possibility that electrical protection systemswill be ineffective.



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8.11.2.3 Earthing of conductive parts

AS/NZS 3000 requires that all conductive parts of an installation be earthed to protect against

differences of potential due to a fault.

Figure 34. Metal glands in plastic enclosure

The switch is not the correct type for terminating

armoured cables.For all parts of the installation to be earthed theglands and the armouring must be effectivelyearthed.

The risk of electric shock due to indirect contactis increased if the extraneous conductive partsare not effectively earthed.

Recommendation 14. Mines sites should review all electrical installationsto ensure that the earthing requirements of AS/NZS 3000 and AS 3007 are met.

8.11.2.4 Earth leakage protection

AS/NZS 3000 requires that RCD units be fitted for the protection of socket outlets and

lighting circuits where there is an elevated risk. In 8% of circuits containing socket outletsand 55% of lighting circuits RCD protection was not present.

Figure 35. Control station with socket outlet fitted

The enclosure has had a socket outlet fitted to the outside.

The socket outlet had been fitted as an addition sometime after the originalinstallation. It had no RCD protection, which increases the risk of electricshock due to indirect contact.

Recommendation 15. All mines should consider the fitting of RCDs to

all lighting circuits, socket outlets and control circuits to field devices thatoperate at low voltage.



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8.11.3.2 Installation

Electrical equipment needs to be installed in accordance with Australian Standards and good

engineering practice. The equipment should be installed in a manner that does not

compromise the design of the equipment.

Figure 37. Distribution board with top cover left off

The installation of this distribution board has not beencompleted.

The top cover has not been fitted, so there is a sizeable gapat the top of the board.

There is a risk of electric shock due to inadvertent contactwith live parts through the opening at the top of theenclosure.

Figure 38. Cable duct with no cover fitted

The duct at the top of the switchboard has nocover fitted. This presents an increased risk ofelectric shock due to insulation damage.

AS/NZS 3000 requires that all conductorshave single insulation installed in a conduit orduct.



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Figure 39. Cables in flexible conduit entering enclosure

The flexible conduit has been pushed through the opening in the panelwithout regard to proper glanding.

Some of the cables have suffered damage and at the lower end of thepanel the damage is such that the conductors are visible.

Figure 40. Unglanded cables entering enclosure

These cables have not been glandedcorrectly.

The IP rating of the enclosure has beencompromised by the use of the rubber flaparound the cables.



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8.11.3.2.1 Installation (IP rating)

Electrical enclosures should be appropriately IP rated according to the location in which they

will be installed.

Figure 41. Paper used to blank holes in panel

The control panel has had some openings inthe front panel covered with paper and tape.This is not an effective form of IP protection.

Figure 42. Well designed local control station

An installation where the environmentalconditions have been considered in theselection and installation of the equipment.



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8.11.3.2.2 Installation (location of equipment)

Electrical equipment should be installed in a location that will not present an increased risk.

AS/NZS 3000 details locations where certain types of equipment are prohibited from

installation.

Figure 43. Switchboard adjacent to wash tub

This switchboard is near a wash tub. Thelocation is not suitable for electrical equipmentdue to the high risk of people being wet whenoperating electrical equipment.

Figure 44. Building with services

A building column within a workshop.

The column has been used to mount the

necessary services for the workshop.

The socket outlets are close to the water andair services.

The socket outlets are not weatherproofunless the plug that is connected is aweatherproof type.



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Figure 45. Bath house pump

The installation of the pump on the bath housefloor is not fit for purpose.

It is located in an area which is regularlyhosed down and is not suitably IP rated for

this location.

Figure 46. Dam pump

This pump was installed when the water levelwas much lower than shown.

A workman must stand in the water in order tooperate the local isolator.



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8.11.3.2.3 Installation (main switchrooms and switchyards)

Switchrooms and switchyards are important items of electrical equipment due to the

switching of high energy sources within the enclosures. As such they have some special

requirements and should be maintained to a high standard.

Figure 47. Switchroom with doors bolted shut

Access to switchrooms is important in order toexit in case of emergency. AS/NZS 3000requires that there be two exits that can beopened from the inside without the use of akey or tool.

This switchroom has sustained damage to theexit doors. The doors are nailed shutpreventing anyone from exiting in anemergency.

Figure 48. Switchroom with door that opens inward

The doorway to this switchroom opens to the inside making it difficult to exitfrom the inside in an emergency.



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Figure 49. Elevated substation installation

Many mine sites are supplied with electric power by means of poletop transformer installations.

This installation is laid out in a way that the safe isolation of the HVfuses would be difficult.

Figure 50. Switchroom

This switchroom is in need of maintenance toallow ready access.

The door is hard to open due to the build up ofdebris around the switchroom.



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8.11.3.2.4 Installation (Signs)

Requirements for signs to be fitted to all electrical installations are detailed in AS/NZS 3000,

AS 3007 and the legislation. Adequate signs are necessary in order to warn of the presence

and the dangers of electricity. The assessment project revealed that 73% of electrical

installations at coal mining sites do not comply with the Coal Mines (General) RegulationsClause 29 and that 70% of sites in the metalliferous and extractive sectors do not have the

required signs.

Figure 51. Enclosure with no signs

There are no signs attached to the electricalenclosures. These enclosures should havesigns stating the presence and danger ofelectricity and the highest voltage within thepanel.

Figure 52. Enclosure with paper signs

The use of homemade paper signs does notadequately cover the requirements ofsignage in AS/NZS 3000 or the legislation.



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Figure 53. Sign on switchyard fence

The sign on the switchyard fence is no longerlegible.

Figure 54. MCC with a high standard of signage.

A switchboard that has been well fitted outwith signs.

The type of signs that should be located at all electrical installations are: Sign to indicate the presence and dangers of electricity and the highest voltage within the

enclosure

Sign to indicate the steps to take in case of a fire occurring on the electrical equipment

Sign to indicate the procedure for resuscitating a victim of electric shock

Sign to indicate the circuits controlled by the equipment

Recommendation 16. All mines should review the signs and notices at all

electrical installations on site to ensure that the requirements of the Coal Mines(General) Regulations, AS/NZS 3000 and AS 3007 are complied with.



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8.11.3.3 Commissioning

Electrical equipment must be installed and commissioned in accordance with AS/NZS 3000.

Section 6 Testing and Verification details the inspection and tests required for new and

modified installations.

Figure 55. Main switch with smaller conductors

The installation of a replacement main switchis unsuitable. The existing conductors are toolarge for the terminals of the new switch sosmaller lengths of conductor have been usedto connect the switch.

Inappropriate installation and commissioningprocedures means this issue has not beenidentified.

8.11.3.4 Use

Electrical equipment should always be used in accordance with the equipment design and

good engineering practice. Equipment safety should never be compromised by bypassing

functions or protection systems.

Figure 56. Badly rusted enclosure

An electrical enclosure that is badly corroded.

It is possible to place your finger through thehole. Note: The power was isolated when thisphotograph was taken.

Equipment should not be allowed todeteriorate.



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Figure 57. Contactors wedged in

Wooden wedges have been used to hold contactors in theclosed position.

8.11.3.4.1 Use (access to switchboards)

AS/NZS 3000 requires there be clear access to all switchboards.

Figure 58. Access to distribution board is restricted

This distribution board cannot be opened due to the practice of storingequipment in front of the switchboard.



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8.11.3.5 Maintenance

In order for electrical equipment to remain in a fit for purpose condition, maintenance must

be effective and appropriate to the task. The maintenance must consider the ongoing

compliance with AS/NZS 3000 and AS 3007.

Figure 59. Switchboard cell held with tape

A section of this switchboard has had somerepairs carried out.

The cover of the panel no longer fits, as thenew equipment is larger in size. The cover isheld on with insulation tape.

Figure 60. Unloomed conductors in an enclosure

The wiring in the enclosure is not contained within ducting or ina wiring harness.

There are no identification numbers on wiring making faultfinding difficult.

When maintenance practices are such that enclosures are keptin this condition it indicates that plant standards are unsuitablefor ensuring equipment is kept in a fit for purpose condition.



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Figure 61. Stray wires in an enclosure

The condition of the enclosure is an indicator of a lack of maintenance.The wiring is not restrained or marked and redundant equipment has notbeen removed.

Figure 62. Enclosure that dust has entered

The enclosure is not suitable for the environment that it is installed in.

The environment is very dusty and, although the enclosure may havebeen dustproof when installed, a lack of maintenance has seen the sealsdeteriorate.

The result is that a significant amount of dust now enters the enclosureand the installation is no longer in a fit for purpose condition.



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8.11.3.6 Disposal

When electrical equipment is no longer required (become redundant) it needs to be managed

so that it does not present a risk of electric shock.

Figure 63. Redundant cables

These cables are redundant. They have been disconnected and left tohang under the cable tray.

This practice increases the risk of electric shock due to the redundantcables being inadvertently re-energised.

Figure 64. Redundant cable poked behind adjacent cable

The redundant cable has not been handledwell. It has been cut off and placed behindthe adjacent cable.



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9 Legislation

9.1 Differences between mining and non mining electrical installations

Electrical installationsin mining are not similar to mainstream industry and have

traditionally been regulated under a different legislative model than the "ordinary" workplace.

There are many situations in mining where electrical installations differ markedly from those

normally encountered in the non mining workplace.

Some are listed here:

Installations tend to be temporary, and mining operations are continuously moving.

Transportable / relocatable high voltage substations.

Earthing installations at the bottom of open cuts where effective connection to the mass ofearth is exceedingly difficult.

Frequent use of explosives with electrically initiated detonators.

Very large diesel powered mobile machines with on board generating equipment and highvoltage electric drive traction, with attendant fire and malfunction risks.

Processing and beneficiation plants where electrical apparatus is continuously wet andexposed to conductive and corrosive mineral slurries and concentrates.

High voltages (now up to 22 kV) reticulated inflexible cables to very large mobilemachines.

Particular earthing requirements for trailing cable fed mobile machines.

Overhead lines on sites with material stock piles, large earth moving equipment and largedump trucks (generally larger than standard road vehicles) where the height of the ground

below the line may be subject to change.

High voltage cables installed where persons and machinery can contact them. High voltage cables installed in confined roadways underground where probability of

exposure is very high, and possibility of retreat from danger is limited.

High voltage installations where persons are routinely required to stand knee deep in mudand water to maintain and operate them.

Large high powered machines supplied with trailing cables, where free steered vehiclesrun in close proximity.

High powered machinery controlled with radio remote controls in restricted space, withpersons closely concentrated around the machine.

Very deep shaft vertical and slope winders conveying large numbers of persons. Some other issues unique to mining that impact on electrical engineering safety are:

Office buildings and workshop / store complexes are on site and staffed by the samepeople who operate the mine. Machinery and plant migrates from store to mine to

workshop etc. It would be impractical to have different legislation for electrical

installations for different parts of the mine.

Some mines (including office and workshop) are powered only by on site privatelyowned generating plant. Such installations are best regulated by specific mining

legislation.

Some mines that begin life as open cut operations later become underground mines.

Many mines are remote from population centres, making it difficult to access the licensedtradesmen and consulting engineers with particular expertise.



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9.2 Legislative models

Electric Shock Final Report

Documents

Transcript of Electric Shock Final Report