T HR EL 08006 ST
Standard
Services Erected Above Overhead
Wiring
Version 1.0
Issued Date: 10 October 2014
Important Warning
This document is one of a set of standards developed solely and specifically for use on the rail network owned or managed by the NSW
Government and its agencies. It is not suitable for any other purpose. You must not use or adapt it or rely upon it in any way unless you
are authorised in writing to do so by a relevant NSW Government agency.
If this document forms part of a contract with, or is a condition of approval by, a NSW Government agency, use of the document is
subject to the terms of the contract or approval.
This document may not be current. Current standards are available for download from the Asset Standards Authority website at
www.asa.transport.nsw.gov.au.
© State of NSW through Transport for NSW
T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
Standard governance
Owner:
Lead Electrical Engineer, Asset Standards Authority
Authoriser:
Chief Engineer Rail, Asset Standards Authority
Approver:
Director, Asset Standards Authority on behalf of ASA Configuration Control Board
Document history
Version
Summary of change
1.0
First issue
For queries regarding this document,
please email the ASA at
[email protected]
or visit www.asa.transport.nsw.gov.au
© State of NSW through Transport for NSW
T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
Preface
The Asset Standards Authority (ASA) is an independent unit within Transport for NSW (TfNSW)
and is the network design and standards authority for defined NSW transport assets.
The ASA is responsible for developing engineering governance frameworks to support industry
delivery in the assurance of design, safety, integrity, construction, and commissioning of
transport assets for the whole asset life cycle. In order to achieve this, the ASA effectively
discharges obligations as the authority for various technical, process, and planning matters
across the asset life cycle.
The ASA collaborates with industry using stakeholder engagement activities to assist in
achieving its mission. These activities help align the ASA to broader government expectations of
making it clearer, simpler, and more attractive to do business within the NSW transport industry,
allowing the supply chain to deliver safe, efficient, and competent transport services.
The ASA develops, maintains, controls, and publishes a suite of standards and other
documentation for transport assets of TfNSW. Further, the ASA ensures that these standards
are performance based to create opportunities for innovation and improve access to a broader
competitive supply chain.
This standard supersedes RailCorp standard EP 08 00 00 14 SP Services Erected Above
Overhead Wiring, Version 2.1.
The changes to previous content include:

updates to reflect organisational changes and resulting changes in responsibilities

minor amendments and clarification to content

conversion of the standard to ASA numbering, format and style
© State of NSW through Transport for NSW
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T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
Table of contents
1.
Scope and application...........................................................................................................................5
2.
Reference documents ...........................................................................................................................6
3.
Terms and definitions ...........................................................................................................................6
4.
Risks associated with service crossings............................................................................................6
5.
Installation requirements ......................................................................................................................7
5.1.
5.2.
5.3.
5.4.
5.5.
5.6.
5.7.
5.8.
5.9.
Materials................................................................................................................................................................. 7
Clearance requirements ....................................................................................................................................... 7
Position .................................................................................................................................................................. 8
Crossing angle ...................................................................................................................................................... 8
Support .................................................................................................................................................................. 8
Joints...................................................................................................................................................................... 8
Bonding.................................................................................................................................................................. 8
Cables .................................................................................................................................................................... 9
Access prevention barriers .................................................................................................................................. 9
6.
Impact on maintenance of overhead wiring......................................................................................10
7.
Data set associated with the services ...............................................................................................10
7.1.
7.2.
7.3.
Tunnels, overline bridges and air space developments .................................................................................. 10
Services attached to overhead wiring structures............................................................................................. 10
Pipeline bridges................................................................................................................................................... 10
© State of NSW through Transport for NSW
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T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
1.
Scope and application
This document specifies the minimum requirements in order to ensure electrical safety for
service crossings above the 1500 V overhead wiring where the service spans the rail line or is
attached to a fixed structure that spans the rail line. For example:

in tunnels

beneath overline bridges

attached to portal structures

beneath air space developments

at pipeline bridges
The types of services may include the following:

high voltage cables

low voltage cables

signal cables

communication cables

water pipes

sewerage pipes

fire detection and sprinkler systems
The requirements for electric aerials crossing RailCorp infrastructure is contained in document
EP 10 01 00 05 SP Requirements for Electric Aerials Crossing RailCorp Infrastructure.
Services carrying dangerous goods, such as gas pipes, may require additional measures.
These are not included in this document. Details of such installations are to be assessed by the
relevant AEO and submitted to the Lead Electrical Engineer ASA for approval prior to
installation.
This document applies to all new service crossings and where modifications are carried out to
existing service crossings.
© State of NSW through Transport for NSW
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T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
2.
Reference documents
Australian standards
AS 1214: 1983 Hot-dip galvanized coatings on threaded fasteners (ISO metric coarse thread
series)
Transport for NSW standards
EP 08 00 00 01 SP Overhead wiring standards for the electrification of new routes
EP 10 01 00 05 SP Requirements for Electric Aerials Crossing RailCorp Infrastructure
EP 12 10 00 21 SP Low Voltage Installations Earthing
EP 12 20 00 01 SP Bonding of Overhead Wiring Structures to Rail
EP 20 00 00 20 SP Testing of high voltage and 1500V dc cables
ESC 215 Transit space
ESC 330 Overhead wiring structures and signal gantries
T HR EL 08001 ST Safety Screens and Barriers for 1500 V OHW Equipment
T HR EL 12002 GU Electrolysis from Stray DC Current
3.
Terms and definitions
AEO Authorised Engineering Organisation
ASA Asset Standards Authority
PFC Parallel Flange Channel
TfNSW Transport for New South Wales
4.
Risks associated with service crossings
The installation of service crossings above 1500 V overhead wiring is not desirable as this
situation may reduce the clearance above the overhead wiring and will lead to risks involving:

overhead wiring touching the service due to temperature variations, dynamic wire
movements, or failure of equipment such as pantographs, resulting in dangerous potentials
being transferred to the service

the service falling on the overhead wiring due to failure of the support arrangements
resulting in dangerous potentials being transferred to the service

objects falling from the services installation or from persons accessing the services above
the overhead wiring
© State of NSW through Transport for NSW
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T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014

damage to overhead wiring equipment and / or disruption to traffic due to objects falling
from the services installation

damage to structure or services due to electrolysis

touch potential between services connected to a remote earth and overhead wiring
structures

effects on services due to exposure to heat and diesel exhaust emitted from locomotives

work near live 1500 V equipment due to construction and maintenance activities for the
services
Where installation of services above the overhead wiring can not be avoided, the requirements
of this document shall be complied with.
5.
Installation requirements
5.1.
Materials
Service ducts and other components of the service crossing shall be capable of withstanding, at
their installed positions, heat and diesel exhaust emitted from locomotives when stationary
beneath the ducts.
Materials used in the service crossing shall not fail due to corrosion or degradation within the
design life of the service crossing. Fasteners shall be made of material such as stainless steel
or mild steel galvanised in accordance with AS 1214: 1983. Commercial grade plated steel
fasteners and wood products shall not be used.
Non-metallic ducts shall be made of ultraviolet stabilised material.
5.2.
Clearance requirements
The minimum clearances to 1500 V equipment are stipulated in EP 08 00 00 01 SP. Reduced
and special reduced clearances are applicable to non-conducting material only, and can only be
used after assessment by the appropriate design authority of the relevant Authorised
Engineering Organisation (AEO) and approval of the Lead Electrical Engineer ASA.
Clearance requirements to the transit space are set out in ESC 215 Transit space.
Greater clearances should be adopted as far as practicable, and shall be adopted if required
from the outcome of a risk assessment.
© State of NSW through Transport for NSW
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T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
5.3.
Position
Services shall be positioned to minimise the risk of being struck by damaged pantographs and
the effects of heat and diesel exhaust emitted from locomotives when stationary beneath the
services. For example, where services are attached to a bridge beam, they should be positioned
above the lowest point of the beam and, where possible, on the side of the beam that is
opposite to the approach side of train travel. For 'I' type bridge beams, the services shall be
positioned between the flanges of the beam where possible.
5.4.
Crossing angle
To minimise the exposure to the risks as listed in Section 4, services shall cross tracks at
approximately right angles wherever possible. The angle between the service crossing and the
track shall not be less than 45 degrees.
5.5.
Support
Services shall be rigidly supported in such a way that they will not fall down with the failure of
any one of the support brackets. To minimise the risk of objects falling onto the overhead wiring,
support brackets shall not be located directly above 1500 V overhead wiring or equipment.
Support brackets within 3 m of 1500 volt equipment shall be positioned at half the normal
spacing for that type of installation.
Support systems shall positively secure the services on both sides of the overhead wiring.
'Spring clip' saddles and single sided saddles shall not be used.
Where a structure is used to support both the service crossing and the overhead wiring, an
analysis on the strength of the structure shall be done to ensure that it is adequate for the
application.
5.6.
Joints
There shall be no joints in services and ducts located within a horizontal distance of 1.5 m from
1500 V equipment.
5.7.
Bonding
In
all
cases
EP 12 20 00 01 SP
Bonding
of
Overhead
Wiring
Structures
to
Rail,
EP 12 10 00 21 SP Low Voltage Installations Earthing and T HR EL 12002 GU Electrolysis from
Stray DC Current shall be referenced to determine requirements on bonding and earthing.
© State of NSW through Transport for NSW
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T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
5.8.
Cables
5.8.1.
Position of cables on overhead wiring structures
Refer to ESC 330 Overhead wiring structures and signal gantries for the range of standard
overhead wiring structures.
Where cables are supported on portal bridges or booms of cantilever masts, the cables shall not
be positioned below the lowest surface of the portal bridge or boom. Where the portal bridge
consists of an 'I' beam or parallel flange channel (PFC), and there is sufficient space, cables
shall be installed between the flanges and close to the web of the portal bridge beam.
The position of the cables shall be such that the cables will not be damaged by activities such
as rigging on the boom or portal bridge.
5.8.2.
Cable support systems
High voltage and 1500 V cables may be installed without service ducts, provided that:

the cables are supported at intervals in accordance with design and manufacturer’s
recommendation

for 1500 V negative cables, the insulation resistance between any metallic cable supporting
structure and the conductor is tested and confirmed to be satisfactory. See
EP 20 00 00 20 SP for details of insulation resistance tests
All other cables shall be installed in service ducts.
Lids for cable troughings shall be positively secured. 'Snap on' lids shall not be used.
Cables supported on cable trays shall be positively secured. Unsecured cables on cable trays
are not acceptable.
Cables inside metallic ducts shall be double insulated if the metallic ducts are not connected to
the earthing system for the cables. Where conduits are used, rigid conduits shall be used for
straight runs, while flexible conduits are permissible for bends only.
5.9.
Access prevention barriers
If, as a result of the installation of the service, unauthorised persons could come near or above
exposed 1500 V equipment, barriers shall be installed to prevent such access. Refer to
T HR EL 08001 ST Safety Screens and Barriers for 1500 V OHW Equipment for requirements
of such barriers.
© State of NSW through Transport for NSW
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T HR EL 08006 ST
Services Erected Above Overhead Wiring
Version 1.0
Issued Date: 10 October 2014
6.
Impact on maintenance of overhead wiring
Service crossing installations shall not adversely affect the maintainability of the overhead
wiring. Such installations shall not restrict the replacement of overhead wiring support brackets
or the relocation of such brackets on existing overhead wiring structures.
Maintenance access to overhead wiring support brackets and the associated fasteners shall not
be impeded as a result of the service installation.
7.
Data set associated with the services
Appropriate data of the services shall be maintained for the maintenance and future
modification of the overhead wiring. The data requirements for the cases covered in Sections
7.1, 7.2 and 7.3 are detailed below. Data maintenance requirements may be needed for other
cases by agreement between the OHW Maintainer and the Lead Electrical Engineer ASA.
7.1.
Tunnels, overline bridges and air space developments
Where services are installed below the lowest level of any structural beam or deck, the location
of the services shall be shown on the overhead wiring layout and relevant cross sections and
arrangement drawings, such as overline bridge fitting arrangement drawings and wire profiles,
if:
7.2.

1500 V equipment is attached to the structural beam or deck, or

the clearance between the services and any 1500 V equipment is less than 1.0 m
Services attached to overhead wiring structures
Where services are attached to a cantilever mast boom or a portal bridge, such services and
any associated bonding arrangement drawings, shall be indicated by a note and referenced on
the overhead wiring layout.
7.3.
Pipeline bridges
Where a service crossing above the overhead wiring consists of a pipeline and/or its supporting
structure only, the location of the pipeline crossing, and any associated bonding arrangement
drawings, shall be shown on the overhead wiring layout.
If the overhead wiring is attached to the structure supporting the pipeline, details of the
attachment shall be shown on arrangement drawings and wire profiles. A note shall also be
made on the overhead wiring layout referencing the arrangement drawings.
© State of NSW through Transport for NSW
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