Elec
Elec
Elec
AS/NZS 4853:2012
This Standard was issued in draft form for comment as DR AS/NZS 4853.
AS/NZS 4853:2012
COPYRIGHT
Standards Australia Limited/Standards New Zealand
All rights are reserved. No part of this work may be reproduced or copied in any form or by
any means, electronic or mechanical, including photocopying, without the written
permission of the publisher, unless otherwise permitted under the Copyright Act 1968
(Australia) or the Copyright Act 1994 (New Zealand).
Jointly published by SAI Global Limited under licence from Standards Australia Limited,
GPO Box 476, Sydney, NSW 2001 and by Standards New Zealand, Private Bag 2439,
Wellington 6140.
PREFACE
This Standard was prepared by the Joint Standards Australia/Standards New Zealand
Committee EL-001, Wiring Rules, to supersede AS/NZS 4853:2000.
This revision was prepared to address experience gained with the implementation of
AS/NZS 4853:2000.
This revision is a general revision of the Standard and introduces a risk based design
approach to address electric shock hazard situations and respective mitigation methods.
The significant changes in this revision include
(a) the Standard has been restructured to improve its clarity;
(b) a structured process to assess the likelihood of an electrical hazard being present on a
metallic pipeline, and the methodology by which the risk level associated with the
hazard is calculated, and the effectiveness of methods to reduce the risk to an
acceptable or in the ALARP region to a tolerable level is provided;
(c) a safety management methodology to document the assessment and control of
electrical hazards is introduced, together with requirements for these to be reviewed
at defined intervals to assure the ongoing effectiveness of the control; and
(d) the appendices are revised and expanded.
This Standard has adopted the risk based assessment criteria developed by Energy Networks
Australia and Electrical Engineers Association (New Zealand) to align the safety
requirements of this Standard with those of the electrical power industry.
Symbols used in equations in this Standard are defined in relation to the particular
equations in which they occur.
The term informative has been used in this Standard to define the application of the
appendix to which it applies. An informative appendix is only for information and
guidance.
Statements expressed in mandatory terms in notes to tables are deemed to be requirements
of this Standard.
3 AS/NZS 4853:2012
CONTENTS
Page
FOREWORD .............................................................................................................................. 5
SECTION 2 SAFETY
2.1 GENERAL ................................................................................................................ 13
2.2 RISK CONTEXT ....................................................................................................... 13
2.3 ASSESSMENT AND MANAGEMENT OF ELECTRICAL HAZARDS .................. 14
2.4 RISK ASSESSMENT ................................................................................................ 14
2.5 EFFECTIVENESS OF RISK TREATMENTS .......................................................... 15
2.6 CONSTRUCTION SAFETY ..................................................................................... 15
APPENDICES
A LIST OF REFERENCED DOCUMENTS.................................................................. 69
B LOAD CURRENT LFI EXAMPLE CALCULATION .............................................. 70
C FAULT CURRENT LFI EXAMPLE CALCULATION............................................. 74
D EFFECTS OF AN A.C. TRACTION SYSTEM ON A NEARBY PIPELINE ............ 84
E LFI CALCULATION ................................................................................................ 89
F SAMPLE CALCULATION OF CAPACITIVELY COUPLED CURRENT .............. 95
G EPR NEAR A HIGH VOLTAGE INSTALLATION ................................................. 99
H MECHANICAL HANDLING OF PIPE LENGTHS ................................................ 134
I POTENTIAL ISSUES BETWEEN PIPELINE PROTECTIVE EARTHING
EQUIPMENT AND CATHODIC PROTECTION SYSTEMS ................................ 136
J ELECTRICAL HAZARD CONTROL AND RISK TREATMENT ......................... 139
K CONTACT SCENARIOS ........................................................................................ 145
L SOIL RESISTIVITY GUIDELINES........................................................................ 150
M ELECTRICAL POWER SUPPLY INFRASTRUCTURE ........................................ 153
FOREWORD
The close proximity of high voltage power networks and pipelines can result in hazardous
voltages on the pipeline. Electrical traction systems and lightning activity can also cause
hazardous voltages in pipelines.
This Standard provides guidelines to calculate the magnitude of the electrical hazards, and
to assess the effectiveness of methods used to mitigate the hazard. Because experience has
shown that it may not be practicable to achieve specific voltage limits, the Standard has
adopted a risk management based methodology that requires the application of physical and
procedural controls that will reduce the risk to an acceptable level.
This Standard considers a number of circumstances that give rise to electrical conditions on
pipelines
(a) low frequency induction (LFI) due to parallel or near parallel positioning of the
pipelines and high voltage power lines or high voltage a.c. traction systems;
(b) earth potential rise (EPR) due to pipeline proximity with high voltage power line
towers, underground cable joint bays, substation earth grids, and other earthing
current discharge points;
(c) EPR due to lightning current following lightning strikes adjacent to pipelines;
(d) the effects of lightning current introduced to the pipeline, directly or indirectly, and
the effects due to the electrical properties of the pipeline and its coating;
(e) capacitive coupling due to the placing, temporarily or permanently, of pipelines
adjacent to high voltage power lines; and
(f) the accidental contact of pipelines with other electrical systems such as electricity
distribution or traction systems.
The electrical characteristics of the pipeline are always influenced by the properties of the
protective coating applied to the external surface of the pipe and the effect of this coating
must be considered in any analysis.
AS/NZS 4853:2012 6
S E C T I O N 1 S C O P E A N D G E N E R A L
1.1 SCOPE
This Standard applies to metallic pipelines used for transmission and distribution of fluids,
both buried and above ground. The responsibility for the application of this Standard rests
with the owner, licensee or the operating authority of the pipeline.
This Standard sets down the minimum requirements for managing the safety of personnel
working in the vicinity of pipelines and equipment installed on pipelines and specifically
addresses the requirements for the control of electrical hazards on transmission and
distribution pipelines.
The practical rules and guidelines also provide the basis for an engineering assessment by
competent persons of situations that are not specifically addressed by the Standard.
This Standard describes the mechanisms that create hazardous electrical conditions on such
pipelines and provides guidance on how to calculate and mitigate these hazards to minimize
the risk of
(a) harm to people making contact with the pipeline including employees and the public;
(b) damage to the pipeline coating and metal; and
(c) damage to equipment such as the pipeline cathodic protection (CP) system and
telemetry systems.
The risk management based methodology developed by the power industry for a similar
purpose in power system earthing design has been adopted to provide a consistent approach
to risk treatment for similar electrical hazards in the power and pipeline industries.
Guidance on the treatment of lightning strikes is also provided.
The Standard also recognizes that alternating currents may cause corrosion of metallic
pipelines.
1.2 EXCLUSIONS
This Standard does not apply to pipes installed within a plant or processing environment,
although some of the principles in the Standard may have application in the analysis of
electrical hazards in these areas.
This Standard does not apply to an electrically powered plant used in the construction of
pipelines.
This Standard does not address issues associated with static electricity generated by fluid
flow. Control of static electricity is addressed in AS/NZS 1020.
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AS/NZS 4853:2012
Electrical hazards on metallic pipelines