Engineering Specification
Electrical
L1-CHE-SPE-070
High Voltage Cable Routes
Version: 2
Issued: October 2017
Owner: Chief Engineer
Approved By:
Andrew Russack
Head of Electrical
Engineering
PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION
ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Approval
Amendment Record
Approval Date
11/05/2016
Version
1
25/10/2017
2
Description
Initial issue
Minor corrections and clarifications throughout.
Requirement for fault loop lengths and installation revised.
Usage of sand pits revised and clarified.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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Page 2 of 30
ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Table of Contents
1
Purpose ........................................................................................................................... 6
2
Scope ............................................................................................................................... 6
3
Abbreviation .................................................................................................................... 6
4
Definitions ....................................................................................................................... 6
5
References & Legislations ............................................................................................. 8
5.1
MTM Standards/Documents ............................................................................................. 8
5.2
Rail Industry Standards/Documents ................................................................................. 8
5.3
Australian Standards/Documents ..................................................................................... 8
6
Related Documents ........................................................................................................ 9
7
General ............................................................................................................................ 9
8
9
7.1
Compliance ....................................................................................................................... 9
7.2
Permitted Configurations .................................................................................................. 9
7.3
Cable Route Alignment ................................................................................................... 10
7.4
Under Track Crossings ................................................................................................... 11
7.5
Cable Joints .................................................................................................................... 11
7.6
Cable Fault Loops ........................................................................................................... 11
7.7
Ground Entry Arrangements ........................................................................................... 13
Separation of Services ................................................................................................. 14
8.1
Underground Conduits .................................................................................................... 15
8.2
Structure Mounted Conduits ........................................................................................... 15
8.3
Ground Level Troughing ................................................................................................. 15
8.4
Metallic Trunking ............................................................................................................. 16
Cable Pits and Chambers ............................................................................................. 16
9.1
Pit and Chamber Types .................................................................................................. 16
9.2
Pit and Chamber Locations ............................................................................................ 16
9.3
Formed Pit and Chamber Requirements ........................................................................ 17
9.4
9.3.1
General ......................................................................................................... 17
9.3.2
Pit or Chamber Size ...................................................................................... 17
9.3.3
Pit or Chamber Installation ........................................................................... 18
9.3.4
Cable Entry ................................................................................................... 18
9.3.5
Cable Support ............................................................................................... 18
9.3.6
Protection ...................................................................................................... 19
9.3.7
Pit Access ..................................................................................................... 19
Sand Pit Requirements ................................................................................................... 19
9.4.1
Location Requirements ................................................................................. 19
9.4.2
Construction .................................................................................................. 20
9.4.3
Protection and Marking ................................................................................. 20
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
10
Version: 2
Effective from: 25th October 2017
Conduit .......................................................................................................................... 21
10.1
Conduit Requirements .................................................................................................... 21
10.2
Conduit Installation ......................................................................................................... 21
10.3
Underground Installation ................................................................................................. 22
10.4
10.5
10.3.1
Installation by Excavation ............................................................................. 22
10.3.2
Bored Installation .......................................................................................... 23
10.3.3
Protection ...................................................................................................... 24
Structure Mounted Installation ........................................................................................ 25
10.4.1
Acceptable Usage Cases ............................................................................. 25
10.4.2
Installation Requirements ............................................................................. 25
10.4.3
Protection and Labelling ............................................................................... 25
10.4.4
Strength ........................................................................................................ 25
Spares ............................................................................................................................. 26
11
Direct Buried Cable....................................................................................................... 26
12
Ground Level Troughing and Trunking ....................................................................... 26
13
14
12.1
Acceptable Usage Cases ............................................................................................... 26
12.2
Ground Level Troughing ................................................................................................. 26
12.3
Trunking .......................................................................................................................... 26
Marking, Labelling and Record Keeping ..................................................................... 27
13.1
Recording of Cable Routes and Cable Plans ................................................................. 27
13.2
Cable Route Markers ...................................................................................................... 27
13.3
Cable Labelling ............................................................................................................... 28
13.4
Pit Marking ...................................................................................................................... 28
Construction ................................................................................................................. 28
14.1
Qualification .................................................................................................................... 28
14.2
General ........................................................................................................................... 28
14.3
Fill and Compaction ........................................................................................................ 29
15
Installation in Tunnels .................................................................................................. 29
16
Inspection and Testing ................................................................................................. 29
16.1
Conduit Testing ............................................................................................................... 29
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Table of Figures
Figure 1: Typical Fault Loop Installations for Joints – Sand Pit...................................................... 12
Figure 2: Typical Fault Loop Installation for Joint – Formed Pit ..................................................... 12
Figure 3: Typical Fault Loop Installation for Joint – Formed Pit ..................................................... 12
Figure 4: Typical Fault Loop Installation – Sand Pit for Ground Entry from a Structure ................. 13
Figure 5: Typical mechanical protection on 1500V mast ............................................................... 14
Figure 6: Separation Distance ....................................................................................................... 15
Figure 7: Cable Joint Supported in Pit ........................................................................................... 19
Figure 8: Sand Pit Construction .................................................................................................... 20
Figure 9: Typical Pit Entry – Conduit sloping away from pit ........................................................... 22
Figure 10: Buried Conduit Installation ........................................................................................... 23
Figure 11: Conduit Protection by Other Services .......................................................................... 24
Figure 12: Mandrel for Conduit Testing ......................................................................................... 30
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
1
Version: 2
Effective from: 25th October 2017
Purpose
This specification sets out requirements for conduits, pits, troughing, trunking and the
configuration of cable routes for MTM High Voltage cables, including but not limited to
traction cables, feeder cables, electrolysis cables and signal or essential services power
distribution cables.
2
Scope
This standard is to be complied with for all installations of MTM High Voltage cables. This
standard does not cover aerial lines associated with the above systems, or installations
within buildings, switchyards or equipment cases.
This specification supersedes VRIOGS 012.2.1 for the purposes of MTM High Voltage
cables except as referred to within this document. Any clarification required shall be sought
from the Head of Engineering – Electrical.
3
4
Abbreviation
AC
–
Alternating Current
DC
–
Direct Current
HV
–
High Voltage
LV
–
Low Voltage
MTM –
Metro Trains Melbourne
O/H
–
Overhead
PTV
–
Public Transport Victoria
S/S
–
Substation
Definitions
Chamber
A formed pit of sufficient size to enable a person to stand and
work within it.
Clean sand
Clean washed river sand free of rocks, clay lumps, tree roots,
building rubble, metal, glass, sharp objects, organic solvents
or other deleterious material that is likely to damage cables.
Constructor
A person or group of people tasked with the control of the
work site that contains the underground cable.
Formed pit
A formed chamber or cable pit installed beneath the ground
for the purpose of containing cable joints, fault loops or
bends.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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Page 6 of 30
ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
High Voltage
Version: 2
Effective from: 25th October 2017
•
For the purpose of this standard the term High Voltage
includes equipment and other electrical apparatus
associated with the following systems:
•
1500V DC Traction (including Traction Negative)
•
Electrolysis
•
6.6kV, 11kV and 22kV feeders
•
650V, 1000V, 2200V, 3300V and 6600V signal or
essential services power distribution
•
It also includes any other equipment operating at
nominal voltages of 650V or above.
Low Voltage
Any voltage less than or equal to 650V, excluding those
systems specifically defined as High Voltage in this standard.
Pit
A formed pit or sand pit
Sand pit
An excavation for the purpose of containing cable joints, fault
loops, or bends, where the excavation is backfilled to the
surface with sand supporting the cables and access reserved
for future maintenance.
Shall
Is used as the descriptive word to express a requirement that
is mandatory to achieve conformance to the standard.
Should
Is used as the descriptive word to express a requirement that
is recommended in order to achieve compliance to the
standard. Should can also be used if a requirement is a
design goal but not a mandatory requirement.
Specification
A set of requirements that are mandatory to be adhered to
achieve MTM’s objectives.
Structure Mounted
Conduit
Conduit mounted in accordance with the requirements of
section 10.4.
Trunking
Galvanised Steel Troughing, installed as described in section
8.0 of VRIOGS 012.2.1 Rev A
Underground
Services
Cables, conduits, pipes or similar that are underground and
used for utilities such as water, power, gas, drainage or
communications.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
5
Version: 2
Effective from: 25th October 2017
References & Legislations
All references to standards or other documents shall be taken to be a reference to the latest
version of that document inclusive of any amendments at the time of reading.
5.1
MTM Standards/Documents
Document Number
IPG OR-01
Electrical Safety Rules
L4-CHE-STD-009
Traction Substations and Tie Stations
L4-CHE-STD-011
L1-CHE-STD-010
Overhead Line Electrification
Train Maintenance Buildings Electrical Systems – Earthing And
Bonding
Railway Bridges – Electrical Protection and Bonding
L1-CHE-STD-016
Track Bonding For Signalling and Traction Return Current
L1-CHE-GDL-029
Chief Engineer’s Directive - Conduit Usage in Sunlight
L1-INF-PRO-001
Protection of Underground Assets and Services Procedure
L1-SDD-STD-006
5.2
Title
Rail Industry Standards/Documents
Document Number
N/A
PTV Infrastructure Drawing Standards
VRIOGS 012.2
Specification for Signalling Supply, Construction and Installation
Standard for Construction of Cable Route and Signalling Civil
Works
VRIOGS 012.2.1
5.3
Title
Australian Standards/Documents
Document Number
Title
AS 1319
Safety signs for the occupational environment
AS 1477
AS 2053
PVC pipes and fittings for pressure applications
Fixed platforms, walkways, stairways and ladders—Design,
construction and installation
Industrial fall-arrest systems and devices - Selection, use and
maintenance
Conduits and fittings for electrical installations
AS 2648.1
Underground marking tape - Non-detectable tape
AS 2865
Safe working in a confined space
Electrical installations (known as the Australian / New Zealand
Wiring Rules)
Electrical installations—Selection of cables
AS 1657
AS 1891.4
AS 3000
AS 3008
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Document Number
AS 3600
Title
AS 3996
Concrete structures
Plastics - Glass filament reinforced plastics (GRP) - Methods of
test
Guidelines on earthworks for commercial and residential
developments
Metal access covers, road grates and frames
AS 4130
Polyethylene (PE) pipes for pressure applications
AS 4702
AS/CA S009
Polymeric cable protection covers
Installation of underground utility services and pipelines within
railway boundaries
Installation requirements for customer cabling (Wiring Rules)
ESAA C(b)2
Guide to the Installation of Underground Cables
SAA HB 29
Communications cabling handbook
N/A
Victorian Service and Installation Rules 2014
N/A
Electricity Safety (Installation) Regulations 2009
AS 3572
AS 3798
AS 4799
6
Effective from: 25th October 2017
Related Documents
Document Number
Title
L1-INF-PRO-001
Protection of Underground Assets and Services Procedure
L2-TRK-PRO-032
Track Procedure – Maintaining Track Integrity
TS-SP015
VicTrack Network Protection Plan
7
General
7.1
Compliance
High Voltage Cable Routes shall comply with this document, AS 3000, the Electricity Safety
(Installations) Regulations 2009 and all other standards detailed in this specification. Where
a conflict exists between those documents and this specification, clarification shall be
sought from the Head of Engineering – Electrical.
7.2
Permitted Configurations
Cables should be installed in buried conduit. Cables shall not be run in a route listed as not
permitted in Table 1.
The use of ground level troughing or metallic trunking for HV cables shall require a safety
and reliability/maintainability case to be presented for endorsement by the Head of
Engineering – Electrical. It shall be demonstrated that underground conduit installation is
impracticable and/or that the works are intended to be temporary.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Effective from: 25th October 2017
Version: 2
Table 1: Permitted Configurations
Buried
Conduit
Structure
Mounted
Conduit
Ground Level
Troughing
Metallic
Trunking
Preferred
Acceptable
With
Endorsement
With
Endorsement
6.6kV/11kV/22kV AC
Preferred
Acceptable
Not Permitted
Not Permitted
1500V DC
Preferred
Acceptable
Not Permitted
Not Permitted
Traction Negative
Preferred
Acceptable
Not Permitted
Not Permitted
Electrolysis
Preferred
Acceptable
Not Permitted
Not Permitted
Signal or Essential
Services Power
Distribution
(650V-6.6kV AC)
7.3
Cable Route Alignment
Cables shall be run in straight lines as far as is practicable within the rail easement. Cables
may be run outside of the rail easement in accordance with an approved design acceptable
to the Head of Engineering – Electrical, as permitted by S.46 of the Electricity Safety Act
1998.
Where cables are required to run parallel to the rail line the route should be aligned as far
as practicable from the rail lines and as a minimum the following clearances shall be
maintained:
Table 2: Minimum Clearances for Route Alignment
Underground Conduit
(except ground entry arrangements,
under track crossings)
Structure Mounted Conduit
Ground Level Troughing
Metallic Trunking
Ground Entry Arrangements
From Outside Rail
From Structure Foundations
4000mm
2000mm
In accordance with VRIOGS 001
3000mm
2000mm
In accordance with VRIOGS 001
3000m from outside rail wherever practicable
3000mm, or in line
No requirement
with structure
Cable routes shall be approved by both the Head of Engineering – Electrical and the Head
of Engineering – Track and Structures or their nominees. Signal and Essential Services
cable routes shall also be approved by the Head of Engineering – Signals or their nominee.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
7.4
Version: 2
Effective from: 25th October 2017
Under Track Crossings
Where cables are required to cross below rail tracks, they shall be run orthogonally to the
tracks.
Cables crossing beneath rail tracks shall be installed in conduit either by boring or
trenching.
The minimum depth when passing below rail tracks shall be 1200mm from the top of rail to
the top of an HV conduit, which shall be maintained for at least 3000mm beyond the
outside rails, or to an attached ground entry arrangement. This requirement is in addition to
the depth requirements specified in section 10.3 which shall be maintained throughout the
rail reserve including beneath cess drains.
7.5
Cable Joints
All cable joints shall be installed within pits – refer to section 9.
No cable joints shall be present in new cable installations where the length of the cable to
be installed is less than the length of cable on a new cable drum. Unnecessary joints in new
cables are not permitted.
7.6
Cable Fault Loops
Fault loops shall be provided for cables with a length greater than 100m. The additional
cable length to be provided in the loop shall be suitable for two replacements of a joint or
termination. The minimum acceptable lengths of fault loops are shown in Table 3 below.
They shall be provided at each termination, and on both sides of a joint.
Table 3: Fault Loop Lengths
Service
Typical termination/joint
length
Minimum acceptable fault loop
length (each side of joints)
22kV
1.2m
2.5m
1500V (pos. or neg.)
500mm
1.2m
3.3kV
800mm
1.8m
2.2kV
300mm
700m
Fault loops shall be installed in the joint or terminating pits or chambers, in such a way as to
ensure that the minimum bending radius of the cable specified by the manufacturer is not
compromised.
Fault loops at the base of terminations on structures shall not involve the crossing of cable
so that the cable length can be pulled through without twisting and should be installed as
shown in Figure 4. Fault loops on either side of joints may contain loops and may be
installed similarly to the illustrations in Figure 1, Figure 2 and Figure 3.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Figure 1: Typical Fault Loop Installations for Joints – Sand Pit
Plan
Elevation
Figure 2: Typical Fault Loop Installation for Joint – Formed Pit
Plan
Elevation
Figure 3: Typical Fault Loop Installation for Joint – Formed Pit
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Additional
length
Sand pit
Conduit – swept bend
Structure
Figure 4: Typical Fault Loop Installation – Sand Pit for Ground Entry from a Structure
7.7
Ground Entry Arrangements
For the ground entry points of cable onto structures, the cable shall be placed in conduit at
not less than 300mm above ground level. The conduit shall extend to a minimum depth of
1000mm before entering a sand pit for a fault loop and should utilise a swept bend.
The effect of the conduit entry and associated sand pit (if present) shall be considered in
the design of the structure’s foundation.
Cables and conduits above ground shall be mechanically protected in accordance with
Clause 219(2) of the Electricity Safety (Installations) Regulations 2009 from a distance of
300mm below ground level to 2400mm above ground level. A sign in accordance with AS
1319 reading “Danger - High Voltage” shall be fixed to the mechanical protection such that
it is easily read from ground level.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Figure 5: Typical mechanical protection on 1500V mast
Any exposed conduit shall either be UV stabilised, or protected by the application of paint.
The paint shall be specified for use on PVC pipe, of colour ‘N43: pipeline grey’ (AS 2007)
and be applied as per the manufacturer’s recommendation.
The conduit shall be sealed at the top end with expanding foam to prevent the ingress of
water or vermin. The conduit shall run directly to an adjacent pit.
8
Separation of Services
Where a service has a standard or operator requirement that specifies a separation, both
that requirement and the requirements of this standard must be met by using the greatest
separation distance of the two.
Communication cables installed near high voltage cables under this specification shall
comply with the requirements of SAA HB 29 and AS/ACIF S009. Other relevant standards
include VRIOGS 012.2.1 for signalling cables, VRIOGS 013.3 for communications
pathways and TS-SP-013 for VicTrack communications cables.
Where a service does not have a standard, the minimum separations specified within this
standard shall be applied.
Greater separation distances may be required in particular installations. The following
should be considered as a minimum:
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Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
•
Maintenance and safe working arrangements (Electrical Access Permits, Track
Access, Confined Spaces, Manual Handling, etc.)
•
Effects on cable ratings
•
Risk of damage to adjacent services as a result of cable failure
•
Risk of damage to cables as a result of failure of adjacent services
Separation distances shall be taken from the nearest outer surfaces of a conduit, length of
troughing or trunking.
Separation
Distance
Figure 6: Separation Distance
HV conduits, trunking or troughing shall be separated by a clear space of not less than 600
mm in any direction from adjacent utility cables or services unless approved otherwise by
the relevant utility owner and maintainer. The above notwithstanding, where HV cables,
conduits, trunking or troughing cross over or under other utility cables or services, they shall
be separated by not less than 300 mm.
8.1
Underground Conduits
Minimum separation between two HV conduits or an HV and an LV conduit, shall be 50mm
except where the conduits are installed within the same bore.
Where two HV cables run in parallel and provide redundancy, they shall have a minimum
horizontal separation of 1000mm. Signal or Essential Services Power Distribution cables
run in parallel and providing redundancy shall have a minimum separation of 3000mm.
8.2
Structure Mounted Conduits
Minimum separation between two HV conduits or an HV and an LV conduit, shall be 50mm.
Where two HV cables run in parallel and provide redundancy, they shall have a minimum
separation of 1000mm, and should be mounted on a separate structure wherever possible.
8.3
Ground Level Troughing
Signal or Essential Services Power Distribution ground level troughing shall have a
minimum of 100mm separation from adjacent services or troughing.
Signal or Essential Services Power Distribution HV cable may be installed within shared
ground level troughing providing it is run within a separate permanent compartment to other
services and in accordance with the requirements of adjacent services. The barrier
between compartments shall be such that an HV cable fault will not cause failure of
adjacent services.
Where two HV cables run in parallel and provide redundancy, they shall not be installed
within the same troughing.
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Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
8.4
Version: 2
Effective from: 25th October 2017
Metallic Trunking
Signal or Essential Services Power Distribution metallic trunking shall have a minimum of
150mm separation from adjacent services or trunking.
Signal or Essential Services Power Distribution HV cables shall not be installed within
shared trunking.
Where two HV cables run in parallel and provide redundancy, they shall not be installed
within the same trunking, and should be installed on separate posts where possible.
9
Cable Pits and Chambers
9.1
Pit and Chamber Types
Formed pits or chambers in accordance with section 9.3 are preferred for all installations
except where the topology is such that the formed pit is unlikely to be able to drain
appropriately and would result in cables and joints being submerged for long periods of
time.
Sand pits in accordance with section 9.4 may be utilised for HV cables for connection to
underground conduits. They may be used only where the requirements of sections 9.4.1
(location and clearance from other services) and 9.4.3 (protection and marking) are able to
be achieved.
9.2
Pit and Chamber Locations
A pit or chamber shall be provided wherever a cable joint is required in a conduit route.
Any bends where, according to the manufacturer’s recommendations, installation of the
cables requires use of rollers shall have a pit or chamber installed.
A pit or chamber shall be provided at each transition between underground conduit,
structure mounted conduit, ground level troughing or trunking, as well as adjacent to each
point of entry to the ground or to a building.
Pits or chambers shall also be provided at regular intervals of not more than 400m to
facilitate ease of installation, maintenance and repair.
Cable pits and chambers shall be installed wholly within the VicTrack rail reserve wherever
practicable.
The edge of cable pits and chambers shall be installed no closer than 3000 mm from the
closest running rail. Cable pits and chambers shall be sited so as not to interfere with
surface drainage.
Communication cables, signalling cables and low voltage cables shall not occupy the same
pits or chambers as HV cables.
Each pit or chamber that contains a HV cable shall contain only cables that are at the same
voltage. Where two HV cables run in parallel and provide redundancy, they shall be
provided with separate pits or chambers.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
9.3
Version: 2
Effective from: 25th October 2017
Formed Pit and Chamber Requirements
9.3.1
General
Formed cable pits or chambers shall generally be of the reinforced concrete preformed type in accordance with AS 3600. Signal Power or Essential Services
Distribution HV cable pits or chambers may be of plastic construction in accordance
with the requirements of VRIOGS 012.2.1.
Cable pit covers shall comply with AS 3996. Pit covers shall be designed to allow
ease of removal manually and shall be sectioned as necessary to limit the maximum
weight to comply with Victorian Occupational Health and Safety Regulations.
For access roads the pit covers shall be Class D (areas open to heavy-duty
commercial vehicles) and for footpaths the pit covers shall be Class C (areas open
to slow moving medium-duty commercial vehicles). Pits in other areas shall have pit
covers installed of a class appropriate to the expected loading.
Pit covers shall be designed to resist the ingress of water and be vermin proof.
Pits shall be designed such that workers can access any conduits, cables or joints
within the pit, generally requiring a chamber of sufficient size to enable a person to
stand within the pit and work comfortably, and to accommodate the cable supports,
cable joints, pulling mechanisms and spare cable lengths as may be required whilst
ensuring the minimum bending radius is adhered to.
9.3.2
Pit or Chamber Size
Pits shall be designed to be an appropriate size for their intended use, taking into
consideration the cable bending radius requirements, conduit entry and exit
locations, any requirement for fault loops and space to complete cable jointing.
Typical pit sizes for some applications are shown in Table 4 below, however the
suitability of these sizes for any particular application must be verified during design.
Table 4: Typical Pit Sizes
Application
Length
Width
Essential Services Distribution System – Joint Pit
2500mm
1500mm
Essential Services Distribution System – Turning Pit
1200mm
1200mm
Essential Services Distribution System – Pulling Pit
2000mm
1000mm
High Voltage Distribution – Joint Pit
4000mm
3000mm
High Voltage Distribution – Turning Pit
3000mm
3000mm
1500V DC – Joint Pit
2000mm
1500mm
1500V DC – Turning Pit
1200mm
1200mm
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
9.3.3
Version: 2
Effective from: 25th October 2017
Pit or Chamber Installation
Cable pit and chamber covers and access covers are to be level with the
surrounding finished surface in all areas subject to pedestrian or road traffic, e.g.
platforms or access roads. For areas which are not subject to pedestrian or road
traffic, the cable pit or chamber shall be 150 mm above the surrounding ground level
to prevent the ingress of water and soil and shall be appropriately battered to the
edge of the pit.
Pits and chambers installed on unpaved slopes shall be installed level, and
protected from being covered by retaining walls or appropriate landscape batters.
Adequate drainage shall be provided for the pit or chamber. If it is impractical to
discharge water seepage from the pit, a drainage sump shall be provided to allow
for transfer of seepage to a decanting system.
9.3.4
Cable Entry
Pits and chambers shall be of sufficient size to make cable joints. Joints in cables
shall be arranged and supported in the pit or chamber in a manner which will
provide for easy access to all joints for future maintenance purposes.
Where conduit or ground level troughing enters a cable pit, the conduit or troughing
shall be encased in concrete for a distance of 300 mm from the pit or chamber to
hold the conduit or troughing securely in position.
Any spare cable entries or conduits provided for future use shall be sealed to
prevent the ingress of soil and water into the pit.
Cable entries to pits or chambers should be tangential to the pit or chamber walls
wherever practicable.
Conduit entries shall be in the form of a bell mouth, smooth and free of sharp edges
to prevent damage to the cable during installation and subsequent operation of the
cable. The conduit entry shall be sealed with a suitable and approved expanding
silicone or similar sealant.
The lowest conduit shall be installed a minimum of 100 mm above the pit or
chamber floor.
9.3.5
Cable Support
Cables shall be supported within the pit by appropriately sized non-ferrous clamps
mounted on structures fixed to the pit walls. The design of cable supports shall be
such to ensure access as required by section 9.3.7 is maintained, and the minimum
bending radius of the cable is maintained. Typically small unistrut cantilevers would
be provided for this purpose.
All cable joints shall be supported at a height which ensures they are above the
water table and will not be regularly submersed.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Figure 7: Cable Joint Supported in Pit
9.3.6
Protection
Non-trafficable pits shall be protected by the installation of a minimum of two white
posts, typically installed on diagonally opposite corners of the pit.
9.3.7
Pit Access
If a pit requires steps or a ladder to provide a safe means of entry or exit due to
being greater than 1m deep or the installation location, access steps or rungs
complying with AS 1657 shall be provided.
As far as practicable, pits shall be designed so that they are not considered as
confined spaces. If this is not achieved, signage shall identify the pit as a confined
space according to AS 2865 and shall be placed in a prominent position so that it is
obvious to anyone intending to enter the pit. The signage shall be designed in
accordance with AS 1319 Safety signs for the occupational environment.
If required for entry and egress, anchorage points suitable for the attachment of two
persons and complying with AS 1891.4 shall be provided with accompanying
signage.
9.4
Sand Pit Requirements
9.4.1
Location Requirements
Sand pits shall be located a minimum of 5000mm clear of any VicTrack assets,
2000mm from any MTM services including adjacent HV conduits and a minimum of
3500mm from the nearest rail. Sand pits which breach these clearances may be
installed only with the permission of the Head of Engineering – Electrical. Existing
sand pits may be reinstated.
Sand pits shall be accessible to an excavator or small truck from a roadway or other
access point without the vehicle fouling the track.
Sand pits shall not be used within paved areas such as roadways or paths –
excavation of the sand pit shall not require the breaking and reinstatement of any
pavement.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
9.4.2
Effective from: 25th October 2017
Version: 2
Construction
Sand pits shall be formed of an excavation of the natural earth to a minimum depth
of 150mm below the lowest conduit or cable to enter within the pit. They shall be
designed and sited such that they do not affect the stability of nearby structures.
Sand pits should not be deeper than 1500mm, to allow ease of safe working within
the pit.
Conduits entering the pit shall extend a minimum of 150mm beyond the edge of the
excavation, and be fitted with bell mouths to protect cables during pulling. Conduit
ends shall be sealed after cable installation using an appropriate product such as an
expanding foam to prevent ingress of sand, soil or water into the conduit.
Fault loops within sand pits shall be laid on a flat horizontal plane and without
crossings, as described in section 7.5.
All cables and conduits within the sand pit shall be surrounded by a minimum of
150mm of clean sand in all directions.
Sand within sand pits shall be compacted in layers of not more than 250mm using
either a mechanical vibrator or hand tools.
Fill
300
>1000
Orange marker tape
>150
150
150
Clean Sand
150
150
Concrete protection barriers
Figure 8: Sand Pit Construction
9.4.3
Protection and Marking
Sand pits shall be marked by the installation of four yellow posts installed at the
corners of the pit. The yellow posts shall have cable route markers attached.
Where the installation of marker posts is impractical, the pit may be marked by the
provision of four monuments with cable route marker plates affixed, and a cable
route marker nearby indicating the relative position of the pit.
Sand pits shall be protected by concrete protection barriers installed 150mm above
the cable or conduit. Such protection barriers shall be either polymeric cable
protection covers to AS4702 or of concrete construction, a minimum of 40mm thick
and with a characteristic strength in accordance with Australian Standards of not
less than 15MPa at 28 days.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
The protection barriers shall be continuous (gaps of less than 50mm) and extend at
least 50mm beyond the vertical line of any HV cable. Areas of the sand pit which do
not contain cables do not require protection barriers.
Orange warning tape to AS 2648.1 shall be installed in the pit backfill, approximately
300mm above the protection barriers. The warning tape within sand pits should
extend 150mm beyond the vertical line of any HV cable.
10
Conduit
10.1
Conduit Requirements
Conduit shall be rigid orange, PVC, heavy-duty type, as per AS 2053 or AS 1477 Class
PN12. Exposed corrugated orange, heavy-duty type PVC may be used only for bends. For
conduits installed by boring, polyethylene (PE) conduit to AS 4130 may be used.
The minimum nominal conduit diameter shall be 100mm, or for 11kV or 22kV services,
150mm. Each conduit shall be sized for the number and installation conditions of the cables
that are to be placed into it.
One cable shall be installed in each conduit, except:
•
Up to two parallel 1500V DC (of the same section) or Traction Negative cables may be
installed in each conduit.
•
Three cables comprising the three phases of one HV circuit may be installed in the
same conduit.
•
Two cables of the same circuit may be run in one conduit from the nearest pit to a
ground entry arrangement.
The internal diameter of the conduit should be greater than:
•
1.65 times the cable diameter for conduits containing a single cable
•
3 times the cable diameter for conduits containing two or three cables
Conduit thickness should be assessed to ensure that under the expected loads including
during construction, there will not be a loss of greater than 10% of the diameter of the
conduit.
Metal conduit shall not be used for HV cables under any circumstances.
10.2
Conduit Installation
All conduit joints shall be made by utilising the spigot and socket ends. Ends to be joined
shall be thoroughly cleaned using a solvent approved by the conduit manufacturer. The
joint shall be impervious to water and shall be glued with an adhesive approved by the
conduit manufacturer.
Conduit shall be installed such that socket ends face the direction from which cables will be
pulled.
A draw wire of 6 mm diameter polypropylene blue/yellow or similar rope shall be placed in
each conduit and suitably anchored at each end. Draw wires should have a minimum of
2m slack at each pit.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Effective from: 25th October 2017
Underground Installation
The minimum depth from the finished ground level to the top of buried HV conduits shall be
1000mm at all times.
Conduits entering formed pits shall slope away from the pit such that water does not flow
into the pit. Conduits entering a building shall not allow water to flow into the building.
Fill
>1000
10.3
Version: 2
Marker tape
Formed Pit
Protection barriers
Clean Sand
Figure 9: Typical Pit Entry – Conduit sloping away from pit
During construction, and for conduits installed for future use, conduit ends shall be sealed
using conduit end caps or an approved equivalent to prevent the ingress of dirt or sludge
into the conduits.
Conduits shall be cleaned and proven with an appropriately sized mandrel after installation,
and test reports forwarded to MTM (see also section 16).
10.3.1 Installation by Excavation
The bottom of the cable trench shall be level across its width and free from any
protrusions and rubble that could cause damage to the conduits. Changes in the
trench gradient shall be gradual. The cable route shall, so far as possible, follow a
constant grade and line. Rough and uneven ground shall be levelled to the extent
necessary to achieve this objective.
The bottom of the trench shall have 100mm of compacted clean sand. Buried
conduits shall be surrounded by a minimum of 50mm of clean sand in all directions.
Levelling work shall not adversely affect railway or natural drainage, or pedestrian or
vehicular access routes.
Cables shall be placed within trenches such that cable voltages increase with depth.
No cable shall run below another cable with a higher voltage.
Conduit routes shall be designed and constructed such that they do not affect the
stability of nearby structures.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Orange Warning Tape
~300
>1000
Fill
>50
HV Conduits
Clean sand
>100
150
Protection barriers
>50
Figure 10: Buried Conduit Installation
10.3.2 Bored Installation
Conduits may be installed by boring only where required by circumstances on site
such as under tracks, when crossing other services or roadways etc.
Where conduits are installed by boring, the diameter of the bored hole should not
exceed the outside diameter of the conduit or encasing pipe by more than 50mm.
Where the diameter of the bored hole exceeds the outside diameter of the conduit or
encasing pipe by more than 50mm, or where it is necessary to abandon a bored
hole, the cavity or hole shall be promptly backfilled with approved materials such as
an appropriate grout.
The design and excavation of underground bores shall be such as to allow safe
pulling of cables through the conduits, with the pulling arrangement to ensure no
bending of cables in excess of the manufacturer’s recommendations.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Effective from: 25th October 2017
Version: 2
10.3.3 Protection
Conduits containing HV cables (except those installed by boring) shall be covered
by protection barriers. Such protection barriers shall be either polymeric cable
protection covers to AS4702 or of concrete construction, a minimum of 40mm thick
and with a characteristic strength in accordance with Australian Standards of not
less than 15MPa at 28 days.
The protection barriers shall be continuous and extend at least 50mm beyond the
vertical line of any HV conduit. Protection barriers should be installed approximately
150mm above the top-most HV conduit but may be installed higher if required due to
the presence of other services.
Protection barriers may be omitted for parts of a trench where other services provide
a similar degree of coverage. An example is shown in Figure 11.
Orange Warning Tape
~300
>1000
Fill
Other Services
HV Conduits
Clean sand
>100
>150
Protection barriers
>50
Figure 11: Conduit Protection by Other Services
For trenched conduit installations orange warning tape to AS 2648.1 shall be
installed longitudinally in the trench backfill, approximately 300mm above the
protection barriers (or highest other service) and shall extend at least 50mm beyond
the vertical line of any HV conduit.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
10.4
Version: 2
Effective from: 25th October 2017
Structure Mounted Installation
10.4.1 Acceptable Usage Cases
Structure mounted HV conduit shall only be installed with the approval of the Head
of Engineering - Electrical on structures such as:
•
On the underside of bridges
•
Through deep cuttings with vertical concrete walls
•
Beneath platforms
10.4.2 Installation Requirements
Structure mounted conduit shall be installed so as to maintain the minimum
clearances as described in section 8.
Conduit shall be permanently fixed to solid structures at regular intervals in
accordance with the manufacturer’s recommendations and shall be designed such
that minimum bending radii of cables are respected.
Structure mounted conduit shall be suitable for exposure to UV unless completely
enclosed in a solid protective barrier or UV protected by the application of paint. The
paint shall be specified for use on PVC pipe of colour ‘N43: pipeline grey’ (AS 2007)
and be applied as per the manufacturer’s recommendation.
The possibility of contact or damage by machinery working in the rail reserve shall
be considered during design.
10.4.3 Protection and Labelling
Structure mounted conduits, except those set in concrete, shall be labelled
“DANGER HIGH VOLTAGE” at regular intervals of not more than 4m and at each
change of direction.
Structure mounted conduit shall be protected from access or accidental damage by
a protective covering.
The protective covering shall either consist of encasing concrete with a minimum
thickness of 50mm, or an inflexible sheet. The protective covering shall either be
solid, or shall be designed with a minimum rating of IP3X such that no body part
(such as fingers) can come into contact with the installed conduit without removal of
the covering. It shall be securely fastened to the same surface as the conduits, and
shall be resistant to deformation from any forces that could reasonably be expected
in normal circumstances (e.g. wind, persons leaning against screens, hail, etc.)
If located in a publically accessible area, the protective covering shall either be
padlocked in place or shall require special tools to be removed.
The protective covering (including encasing concrete) must be signed with the
words “DANGER HIGH VOLTAGE” at regular intervals of not more than 4m and
adjacent to any change of direction.
10.4.4 Strength
The cable installation system shall be designed to have adequate strength to
support the static weight of the cable and covering, resist electromagnetic forces
that may result during an electrical fault, and resist the forces that may result from
thermal expansion of the cable and cable installation system.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
10.5
Version: 2
Effective from: 25th October 2017
Spares
For each set of conduits for a specific voltage level, a minimum of an additional 25%
(rounded up to the nearest whole conduit) of the used conduits shall be installed as spare
conduits. There is no requirement for spare conduit from a ground entry arrangement to the
nearest pit.
For example if five 1500V DC conduits, three 22kV AC conduits and one 2.2kV AC conduit
are to be installed, an additional two conduits for 1500V DC cable, one conduit for 22kV AC
cable and one conduit for 2.2kV AC cable shall be installed as spares.
11
Direct Buried Cable
HV cables shall not be direct buried (except within sand pits for fault loops or cable joints
where additional protection is supplied), so as to ensure maintainability and appropriately
protect cables.
12
Ground Level Troughing and Trunking
12.1
Acceptable Usage Cases
Ground level troughing and metallic trunking may be used only outside of publically
accessible areas of the rail reserve.
Use of ground level troughing or metallic trunking should be avoided for HV Cables and
may be used only for Signal or Essential Services Power Distribution and only with the prior
approval of the Head of Engineering – Electrical. Appropriate usage cases may include
crossings of culverts, watercourses, installation on bridges and short distances of up to
20m between pits or equipment cases.
12.2
Ground Level Troughing
Ground Level Troughing installations shall be in accordance with the requirements of
VRIOGS 012.2.1 Rev. A with regards to Cable Route Type 5, except that troughing lids
must be labelled with the words “DANGER HIGH VOLTAGE”. Troughing lids shall not be
able to be opened without the use of tools.
Only type approved Ground Level Troughing shall be used. Installation shall respect the
minimum bending radius of cables.
12.3
Trunking
Trunking installations shall be in accordance with the requirements of VRIOGS 012.2.1
Rev. A with regards to Cable Route Type 6. Installation shall respect the minimum bending
radius of cables.
Insulated sections or air gaps ensuring 3kV insulation shall be installed within the metallic
trunking every 500m, and on either side of any bridges or stations.
Trunking shall not be fixed to any fences or overhead structures and shall be insulated from
underbridges of concrete construction with ballasted track to a level of 3kV.
No electrolysis, step or touch potential issues shall arise through the installation of trunking.
Relevant standards such as MEST 000002-03 Railway Bridges Electrical Protection and
Bonding shall be considered when the metallic trunking is being designed and the design
shall be reviewed by the Office of the Chief Engineer to ensure appropriate bonding is
included.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
13
Marking, Labelling and Record Keeping
13.1
Recording of Cable Routes and Cable Plans
Effective from: 25th October 2017
In accordance with Clause 218(3) of the Electricity Safety (Installations) Regulations, the
installed route shall be recorded as accurately as practicable with a margin of error not
exceeding 200mm. The northing and easting data shall be recorded at each change of
direction of the cable route.
Where there are existing MTM cables installed in the vicinity of the cable route, a
consolidated cable plan shall be produced by either updating or superseding the existing
plan(s) in compliance with the PTV Infrastructure Drafting Standard.
As constructed cable plans shall be provided for the entire cable installation and in
accordance with AS 4799 and the PTV Infrastructure Drafting Standard. The cable plans
shall include one or more cross sections at crossings and representative locations showing
the installed cable, conduit, trunking or troughing in relation to other cables, conduits and
features such as tracks. It shall be possible to readily identify the path of each individual
conduit in both cross section and plan view if the cross section alters through the route.
Additional cross sections shall be provided to enable this identification.
GPS co-ordinates shall be recorded every ten metres for the entire length of the cable route
/ trench, and at all changes of direction. This method shall also be utilised to capture all:
13.2
•
Cable joint locations.
•
Cable pit locations.
•
Under line crossings
•
Under road crossings
•
Changes of direction
•
Spare Conduits
•
Other significant points of the cable route
Cable Route Markers
Markers shall be provided at the location of all underground cables in accordance with AS
4799.
The markers shall be manufactured, mounted and installed as shown in standard drawings
STD_E0169 and STD_E0170. The marker plates shall be fixed to the post by means of
construction adhesive or appropriate permanent fixing such as riveting.
In the rail corridor markers shall be located above underground cables at:
•
Points of entering and leaving the rail corridor;
•
Each point where the route changes direction by more than 5°;
•
Not greater than 100 m intervals along the route such that at least two markers shall be
visible at any point along the route;
Markers shall not obstruct vehicle access along the side of the track or infringe structure
gauge. In yard areas they shall not obstruct footpaths, walkways, vehicle access ways,
lighting or other railway assets.
Markers for conduit routes shall be mounted on white posts, and markers for sand cable
pits shall be mounted on yellow posts.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
13.3
Version: 2
Effective from: 25th October 2017
Cable Labelling
All installed High Voltage Cables shall be legibly and indelibly marked with an appropriate
identifying label at each end of the cable, and at any cable joints. The label shall be
designed to maintain legibility in the installation conditions for twice the design life of the
cable. A suitable label is a stainless steel stamped type, fixed to the cable with
appropriately sized and tensioned black nylon cable ties.
The label shall state the destination points of the cable and the name of the cable relevant
to appropriate drawings. For example:
•
Section 111/1 (cable 2) – Structure 836 to Caulfield Substation
•
22/17/1 – Caulfield Substation to Structure 872+34
•
2.2kV Feeder – 1GR104 to 3GR106
Each cable shall be uniquely labelled.
13.4
Pit Marking
Formed pit covers shall be labelled with the words “DANGER - Railway High Voltage” on
their outer surface. The labelling should be engraved or embossed and permanently affixed
such that it will remain readable despite expected weathering.
Each pit containing High Voltage Cables shall be marked with an engraved label which
includes the pit number and relevant drawing number. For formed pits these shall be fixed
to the pit cover. For sand pits, these shall be fixed to one or more of the surrounding yellow
marker posts.
14
Construction
14.1
Qualification
All electrical installation work shall be carried out by licenced persons as prescribed by
section 38 of the Electricity Safety Act 1998. Electrical installation work as defined by the
Act includes the laying of conduits and the pulling of cables.
Contractors engaged for the installation of cable routes and cables shall be appropriately
qualified and experienced and shall be approved by the Head of Engineering - Electrical in
advance.
14.2
General
The Constructor shall be responsible for the identification and location of all buried services
and shall comply with the Protection of Underground Assets and Services Procedure (L1INF-PRO-001) as well as the Maintaining Track Integrity procedure (L2-TRK-PRO-032).
The Constructor shall mark the location of all existing cables, drainage and all other
underground services of other authorities in the area to be excavated.
When trenching in the vicinity of gas, water mains or service utility lines, the Constructor
shall comply with any restrictions which may apply to the easement and liaise with the
owners of that easement to establish mutually agreed methods of protection and support
for the services.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Where Pits are to be located within existing pathways, roadways or access areas, the
Constructor shall maintain continuous access in compliance with current MTM standards
throughout construction.
The Constructor shall reinstate any roadways, pathways or access areas to current MTM or
relevant asset owner standards after construction.
Any affected surface drains shall be reinstated by the Constructor.
Any excess spoil not utilised in backfilling must be removed from site by the Constructor
unless approval is given by MTM for an alternative arrangement.
Damage to any service during construction activities shall be the total responsibility of the
Constructor.
All conduits are to be stored undercover, protected from direct sunlight while keeping a
moderate temperature. Plastic sheeting shall not be used as a protection cover as it may
increase the temperature of the conduit and potentially damage its integrity.
14.3
Fill and Compaction
Backfilling and compaction shall be undertaken in accordance with the requirements of
VRIOGS 012.2.1 clauses 6.15 and 6.16.
15
Installation in Tunnels
All cables installed in tunnels (including the MURL) shall not emit toxic combustion
products, shall be classified as low smoke, low toxicity and halogen free, and tested in
accordance with Australian Standards.
In tunnels, PVC conduits shall not be used unless embedded in concrete. An alternative
cable mounting system approved by the Head of Engineering - Electrical shall be used.
16
Inspection and Testing
Inspection and Test Plans shall be prepared and submitted to MTM for approval, which
must be granted prior to construction commencing.
Provision shall be made for inspection of cable routes by MTM representatives prior to
backfilling. An MTM representative shall be invited to witness various tests as appropriate.
10 working days’ notice shall be given of the intention to carry out works for which
witnessing may be required.
16.1
Conduit Testing
Testing shall include mandrel testing of underground conduit installations as required by
section 10.3. An MTM representative shall be invited to witness this testing
The mandrel shall be solid, have diameter not more than 12mm smaller than the internal
diameter of the conduit and be a minimum 230mm in total length and 130mm in flat length.
It shall be pulled through every conduit in both directions by hand or with a machine to
ensure their integrity.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
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Next Review Date: 25/10/2020
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ENGINEERING SPECIFICATION
HIGH VOLTAGE CABLE ROUTES
L1-CHE-SPE-070
Version: 2
Effective from: 25th October 2017
Figure 12: Mandrel for Conduit Testing
After passage through each conduit, the mandrel shall be thoroughly inspected for cuts or
damage. If in the opinion of the MTM representative, there is any doubt as to the freedom
from foreign material or any object or defect that may cause damage to the cable in the
conduit, the constructor shall repeat pass the mandrel through the conduit(s) until the MTM
representative is satisfied.
Approving Manager: Head of Engineering - Electrical
Approval Date: 25/10/2017
PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION
Next Review Date: 25/10/2020
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