Trenching for Underground Cables

8/2/2019 Trenching for Underground Cables

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E T S A U t i l i t i e s D e l i v e r i n g e n e r g y t o S o u t h A u s t r a l i a n s

ETSA Utilities, ABN 13 332 330 749,

a partnership of:CKI Utilities Development Limited,

ABN 65 090 718 880.

HEI Utilities Development Limited,

ABN 82 090 718 951.

CKI Utilities Holdings Limited,

ABN 54 091 142 380.

HEI Utilities Holdings Limited,

ABN 50 091 142 362.

CKI/HEI Utilities Distribution Limited,

ABN 19 091 143 038.

each incorporated in The Bahamas

Copyright2004

TRENCHING AND CONDUIT STANDARD

FOR

UNDERGROUND CABLE NETWORKS

Technical Standard TS-085


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Trenching & Conduit Technical Standard TS - 085

1.0 DEFINITIONS

The term "ETSA Utilities" means :-

ETSA Utilities, ABN 13 332 330 749, a partnership of:

CKI Utilities Development Limited, ABN 65 090 718 880.

HEI Utilities Development Limited, ABN 82 090 718 951.

CKI Utilities Holdings Limited, ABN 54 091 142 380.

HEI Utilities Holdings Limited, ABN 50 091 142 362.CKI/HEI Utilities Distribution Limited, ABN 19 091 143 038.

each incorporated in The Bahamas

1 Anzac Highway, Keswick, South Australia, 5035.

2.0 BACKGROUND

The responsibility for the installation of a trench for the installation of ETSA Utilitiesinfrastructure can be:

The developer for land developments or a customer for network extensions andalterations to the ETSA electrical network.

Council for Power Line Environment Committee (PLEC) projects.

ETSA for capital works and, under specific arrangements, some customer works.

ETSA Utilities may agree to provide a quotation for the installation of a trench on

behalf of a customer or a developer. For access to the list of Civil Contractors utilised

by ETSA Utilities refer to section 15.0.

This Technical Standard is based on the Electricity (General) Regulations 1997. For

any situation that is not covered by this Technical Standard, the requirements of

AS/NZS 3000-2000 shall apply.

Trenching needs to be undertaken in a workman-like manner and must meet therequirements in TS 085 and any other relevant specification. A Civil Works

Compliance form is required prior to any Network connection. Refer to section 14.0

for further information.

Section 5.0 of the ETSA Utilities Terms and Conditions for External Contractor


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A contractor should not work in the area where there is electrical infrastructure, even

if the asset is de-energised without a high degree of due care as the cables can be

easily damaged.To reduce the severity of damage to the outer sheath, all contractors who have to

work in the area of the electrical infrastructure MUST utilise a safe edge (blunt

nosed) shovel.

This style shovel minimises cable damage if a contractor inadvertently comes in

contact with a cable. Any damage to ETSA infrastructure will be at the cost of the

responsible party. If any party is aware of any damage to the electrical infrastructure,ETSA or the electrical contractor undertaking an installation should be notified at the

earliest opportunity. Early notice may reduce future repair costs.

The trench containing the electrical works is a component of the asset inspection

process and it is the responsibility of the developer/customer to ensure that the trench

meets the specification. An ETSA Asset Compliance Officer may inspect the trench

and any requirement for remedial work to a trench to ensure it satisfies this Technical

Standard and any associated specification will be at the developer/customers cost.

If there are any queries on this Technical Standard (TS 085) the Project Officer

responsible for your project should be contacted.

3.0 RETAINING WALLS

A transformer can weigh from 2.0 tonnes for a 150 kVA transformer up to 6.2 tonnesfor a 2000 kVA transformer. There may be a requirement to establish a retaining wall

to ensure the transformer has a stable footing. The involvement of a Certified

Engineer may be required to verify the adequacy of any retaining wall installation.

Council approval may also be required. ETSA Utilities reserves the right to request

engineering calculations for any retaining wall.

A retaining wall for a Padmounted Transformer or a Switching Cubicle will normally

be installed in any location where there is a change in the natural (unchanged) ground

level of 300 mm or more within two metres of the standard easement boundary for the

electrical equipment.

Any retaining wall above 1.0 metre in height will require engineering confirmation of

the design and Council approval.

A R t i i ll t b l t d i t th i t ll ti f d t d


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The retaining wall and backfill must be designed to drain the area behind the wall

completely and to continue to do so indefinitely without blockage, so that hydrostatic

pressure is not exerted on the wall at any time.

Retaining walls shall be constructed of concrete masonry materials. If interlocking

style blocks are utilised, they must be of a pinned or socket and nib type. The two top

courses shall pinned and glued with an epoxy style resin and the top course shall

consist of a glued top capping

Open style interlocking blocks may be acceptable provided the soil is retained. The

use of Geo cloth type material may also be acceptable. To ensure the material to be

utilised for a retaining wall will be acceptable to ETSA Utilities, please contact your

ETSA Utilities Project Officer prior to installation. This style of retaining wall

construction has the potential to require an easement larger than standard.

ETSA Utilities will consider a submission from a certified engineer to a variation to

the construction material utilised for a retaining wall as described in this section.

Material to be retained shall be classified in one of the 3 types listed below:

Coarse grained soil without admixture of fine soil particles. Verypermeable (clean sand or gravel)

Coarse grained soil of low permeability due to admixture of particles ofsilt size.

Residual soil with stones, fine silty sand and granular materials withconspicuous clay content.

Materials not acceptable include very soft or soft clay, organic silt or silty clays, and

medium or stiff clay.

Weep holes shall be provided in the retaining wall at the lowest points. An open drain

shall be provided to remove water from the area of the toe of the wall. A more

effective system of drainage consists of a continuous agricultural pipe located at the

base of all retaining walls and be surrounded by gravel or crushed stone with a

continuous vertical layer of granule material at least 300 mm thick covering the rear

face of the wall area.

Easement to be

Area for ETSAEquipment (onstandardeasement, 3.5 x2.5 m).

Retaining Wall


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RETAINING WALL - FILL Figure 2Retainingwall

ETSATransformer/switching cubicle

300mmminm

Granulated materialbehind all retainingwall sections

Continuous agriculturalpipe the length all retaining

wall sections plus externalweep holes on the lowestsection of the retaining Ground level

NoteRetaining wall to be

built up to the heightof the base

Weep hole

Suitable retaining

Ground level

300mmWeep hole

Ag pipe to exit at thefront of the retaining wall

Ground level

Continuous agriculturalpipe the length all retainingwall sections plus externalweep holes on the lowestsection of the retaining

RETAINING WALL - CUT Figure 3

Retaining WallWith 100mm lipabove ground

ETSATransformer/switching cubicle

Groundlevel

PreferredEasement

Dispensation for the installation of a retaining wall can be granted by the relevant regional

Network Manager when the following can be verified;

The short and long term stability of the transformer will not be compromised.

The easement site will not be impacted by erosion run off, i.e. it can be

demonstrated that the site adjacent to the easement is well consolidated and

/or there is other means of retainment or removal of any run off material.


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There shall be a minimum separation of 50mm between direct laid ETSA cable

circuits. The greater the cable circuit separation, the greater the current carrying

capacity of the electrical cable. If the trench width is such that the minimumseparation can be increased and the 50mm clearance to the trench wall is met, then the

separation should be increased. From time to time there may be a requirement for a

specific separation that is greater then the minimum.

Separation from a trench wall to any ETSA infrastructure will normally be a minimum

of 50mm. This is to reduce any damage to electrical infrastructure from sharp edges,

stones, etc. Under some circumstances ETSA may approve a lesser dimension if it canbe verified the trench edge is such that it will not damage the installed cables or if the

installed conduit is medium or heavy duty.

Dimensions for ETSA infrastructure in this standard are the minimum except where

shown.

The maximum depth of any length of trench or conduit should not be greater then 1.5

metres unless ETSA has approved a section of trench/ conduit installation at a greater

a depth. Any depth beyond this will be labelled an excavation and may require

shoring to be installed. Refer to the Occupational Health, Safety & Welfare

Regulations 1995.

The Trench shall be located, when practicable, in accordance the publication A Code

for the Placement of Infrastructure Services in New and Existing Streets (Services inStreets Code) prepared by the Public Utilities Advisory Committee (PUACC) and

available from the Local Government Association.

All variations to the Construction drawing mustbe noted by the installation contractor

d i l d d th A C t t d ETSA d i

Cables

50mm

Cable circuit separation50mm minimum (refer 4.1)

25mm

25mm

Bottom of trench

Conduit

Bedding Sand


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a development there is a requirement for spare conduits. Spare conduits installed at a

road crossing will need to match the spare conduits in the primary trench. The road

crossing conduits need to be continuous with the primary trench spare conduits.

These conduits will be in addition to the conduits at a road crossing that will be

utilised for a direct buried cable installation.

A road crossing for a low voltage tee off (such as a common service trench) that is not

part of a continuous run of cable only requires a conduit for a cable.

Conduits installed at a road crossing that are for a direct buried cable installation shallextend the full width of the carriageway and extend 900mm into the footpath verge

from the back of kerb.

The electrical designer and contractor responsible for conduit installation at road

crossings should ensure that the appropriate number of conduits are installed. Any

road crossing excavation for continuous conduits needs to consider the cover and

trench floor invert of the conduits that are to be installed in the road verge.

4.3 Requirements for Transport SA Roads

Transport SA have very specific requirements for any work being undertaken on a

Transport SA (TSA) controlled road. The requirements include both excavation and

traffic management and apply to overhead and underground works.

The Transport SA specification for the Excavation and Reinstatement of RoadPavement is available from TSA on (tel 82268222). ETSA Utilities recommends that

any contractor involved with the installation of either underground or overhead

electrical works on a TSA road obtain the latest TSA Standard Specification and be

fully conversant with all of the requirements.

Roadside Significant Sites of an environmental or cultural significance must be

considered by both the designer and the contractor. In country regions TSA have

highlighted most TSA controlled roadside sites with a distinctive but discreet marker.Information and a list of Roadside Significant sites is available from the Land

Development Account Manager at Keswick on 84045439.

Some of the relevant sections of the specification dated February 2003 are detailed

below


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4.3.2. Trenchless method

Multiple conduits can be passed through a single bore or tunnel. There is arequirement though for multiple bores to have a minimum spacing of 10D

between individual bores.

where D = the diameter of the largest conduit.

The minimumdepth of a trenchless bore is 1.5 metres.

4.3.3. TSA Notification

The designer

The electrical designer should submit any design to TSA for comment where

any ETSA infrastructure, ie, poles, cable or conduit, will be running parallel

to the kerb for some distance. This is to ensure any installation takes intoaccount any future road widening.

The Constructor

An electrical or civil contractor will need to submit a Notification of Works

Impacting SA Roads form NICC-251 (refer to sect 15.0 for access) 5

working days prior to the commencement of works. Any civil works that will

be undertaken on a TSA road over a period greater then one day requires 4

weeks notice.

The notice is required for the following:

Any work that requires traffic managementThis includes work on overhead mains

A t h d t hl b i

Minimum1.5 metres

Ground level

10 X 125mm =1.25m minimum100mm conduit

125mm conduit

Bore 1 Bore 2


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There is a requirement that TSA receives within 3 days of the completion of

works a log of any excavation with the construction date, location and depths

and details of the reinstatement.ETSA Utilities also requires a copy of the installation details and who

undertook the civil works with the Civil Works Compliance form. The

form is a part the electrical works compliance and connection process.

4.3.6 Emergency Work

TSA requires verbal notification to the appropriate TSA representative at the

earliest opportunity. This must be followed with the submission of the

Notification of Works Impacting SA Roads form within 24 hours of the

emergency.

4.3.6. Maintenance Period

The contractor undertaking the civil component of the electrical worksassociated with the TSA road crossing will be responsible for the cost of

making good any settlement or other deteriation in the reinstated excavation

for the maintenance period which is one year.

4.4. Installation of Conduits Within Railway Boundaries

Australian Standard AS4799 2000 Installation of underground utility services andpipelines within railway boundaries covers the requirements for both the design and

installation of electrical infrastructure within a railway property.

There is specific design information and approvals that are needed for right of entry as

well as easement agreements.

The form Application to Cross Railways With Electric Power Cables NICC-252

(refer to sect 15.0 for access) must be filled out by the designer a minimum of 28working days prior to any work taking place and forwarded to;

ETSA Utilities Easements Coordinator

level 3, 1 Anzac Highway Keswick 5035

Telephone 84045897 fax 84045193


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An electrical conduit should be a minimum of 2metres deep under any rail line and for

a 3metre distance beyond the outer rails. Conduits in other locations in a railwayproperty must have 1 metre minimum cover. A railway authority may approve a

lesser depth, but the depth must not be less then the ETSA Utilities standard.

4.5 Clearances between Services.

Comms

plant pipe

Comms

plant pits

Gas pipes ETSA LV

power

ETSA HV

power

Comms

plant pipe

150 150 200 100 300

Comms

plant pits

150 1000 200 100 100

Gas pipes 200 200 X 200 200

ETSA LV

power

100 100 200 X X

ETSA HV

power

300 100 200 X X

X = undefined in this application. All clearances are in millimetres

Comms = Telecommunications

Note: These clearances are applicable for the full circumference of the service (360)

These are minimum separations. For any other authority a minimum separation of150mm is required. Greater separation may be requested in the ETSA specification

from time to time.

To achieve these clearances it may be necessary to increase the cover on ETSA cables

and/or conduit or increase the trench width.

4.6 Changes in levels and directional changes

The depth of any conduit installation in the carriageway should match that of any

conduit installation on the road verge (footpath). If this is not achievable the cover at

the end of a conduit at a road crossing should be at the same level as the conduit in the

verge. Conduit bends may need to be installed to achieve this.


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conduits. Appropriate bends with the smallest radius requirement to achieve a

satisfactory clearance to other of services should be utilised.

Retrospective undergrounding projects will provide challenges to the civil contractor

from time to time when other service providers infrastructure is encountered within

the trench. It will be the civil contractors responsibility to resolve these issues and the

assistance of the Project Officer should be sought to ensure that a resolution is agreed

on that is to the satisfaction of ETSA Utilitiespriorto construction.

Below are some examples of conflict and possible solutions

Preferredgradient rise/fall

of conduit100mm per

1metre

ETSAconduit

Note

IfY > 1.5m it may bepreferreble to goover service.

150mmminimumunder service.

G.L.

XSharp bends

X Couplinglocation is notappropriate if there isany tension. This

creates a lip whichcan damage cables

`Y

INCORRECT PREFERRED

G.L.

AlternativeConduit

route

The example shows an in-appropriate conduit coupling with tension applies to both a

straight length of conduit and a bend.

It is important that the developer and electrical contractor establish appropriate ground

levels at the time of the installation of the electrical works to ensure that there is no

requirement to alter ground levels by a third party after installation. Under theElectricity Corporations Act 1999 the SA Independent Regulator can impose a fine for

any breach.

Part 6 of this Act states the following:

38. (1) A person must not, without the written authority of the electricity


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A trench will normally be 600 mm wide but could be up to 1200 mm wide depending

on soil type and footpath location. With consultation with the electrical contractor, a

width of 450 mm may be acceptable. The design drawings should specify any non-typical width.

Reference should be made to the Services in Streets Code for any trench location in

a road reserve.

The depth of the trench shall be such as to achieve a minimum cover of 750 mm above

conduits and 1000 mm above all direct buried cables to finished ground level. A

typical cross section of trench occupied by the underground mains, Telstra and Gas is

shown below

:

Typical

width

(Refer to Services

in Streets Code)

50mm

GAS

TELSTRA

750 mm

450mm

600mm

FOOTPATH

BEDDINGSAND

Property

line

1600mm 600 mm

COMMON SERVICE TRENCHmain Side

KERB

LV HV P/L

50mm

1000 mm

Spare conduit

Cables buried direct

Top of

bedding sand

Notes

Refer section 4.1

50mm

50mm

GAS

TELSTRA750 mm

minm at the

finished

road service

level at thekerb invert

For a TSA

road refer to

sect 4.3

450mm

600mm

BEDDING SAND

600 mm

COMMONSERVICE TRENCH - Road Crossing (non TSA road)

Note

Cover slabs or warning tape is

to be placed 75 mm above

ETSA plant if ETSA istheonly occupant of the road

SPARE CONDUIT

Notes

Refer section

4.1

LV HV P/L

road level


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should be installed for any future cable installations. This method of installation

minimises disruption to footpath and vehicular traffic and business premises.

450 mm

Additional conduit

Refer 5.250mm

Gas, when applicable

Telstra, when applicable

750mm

600mm

Kerb

LV HV P/L 50mm

Warning

tape

200mm

maxm

Property lineFootpath

RETROSPECTIVE UNDERGROUNDING (PLEC)

COMMON SERVICE TRENCH

Bedding sandNotes

Refer to

section4.1

Additional conduitRefer to 5.2.

50mm

750 mm

Bedding sand

Kerb

LV HV P/L 50mm

Warning tape

Property line Footpath

RETROSPECTIVE UNDERGROUNDING (PLEC)

ETSA ONLY TRENCH

200mm

maxm

Notes

Refer

section 4.1

4.8.1 Pit Installations

There are a number of pits of increasing size that are available and the pit that is to be

installed needs to be appropriate for the purpose. The designer also needs to be mind-full of other services.

When conduits are installed into the body of a pit, the conduit needs to be 25 50mm

inside the body. All conduit edges are to have no sharp edges. All conduit entries are

to be capped by the contractor to stop the entry of foreign material between the time of


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Note1 Refer to E1921 sht 2.1

for standard arrangements2 Refer to E1921 sht 6.1 to 6.4

for assembly details3 A P5 pit is preferred for LV

cable junctions and servicearrangements for approvedbelow ground connections

Conduit to finish25mm - 50mm inside pit

CABLE & CONDUIT ENTRY INTO JUNCTION PITS

Extended P5 pit(1 Standard body plus oneshortened body or collar)at preferred 985mm invert

Preferred 0 40mm to pitbottom for low voltagecable entry to ensureappropriate room forcable cones

5.0 CONDUIT REQUIREMENTS

5.1 General

Cables shall be installed in conduits in the following circumstances:

Road crossings

Full length of pathways with restricted access ie, a pathway betweenfenced allotments)

Cables installed through easements.

Public lighting cables

Retrospective undergrounding (i.e. PLEC Projects)

On private property where cables vest in ETSA Utilities (Refer to section

6.0 for all options)Earth cables do not need to be installed in conduits

Where there will be access roads, driveways and footpath crossings greater then 2.5

metres in width, conduits for a cable installation as well as spare conduit requirements

may need to be included in a design.

Full details of the conduits must be included on a design drawing and the As

Constructed drawing must reflect the actual installation. Any breaks in a continuous

conduit installation must be noted as must any changes in the as installed conduit size.

11kV cables must not be installed in the same conduit as low voltage cables

5.2 Spare conduit provision


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For the high voltage: 3x 80mm VLD conduit

Note: Where one LV circuit consists of two or more parallel bundles of

cables, a spare conduit must be provided for each bundle of cables.

5.2.2 When a cable is installed in a conduitTo ensure future access to ETSA infrastructure is kept to a minimum there is

a requirement where cables are to be installed in conduit for additional

conduits.

Unless specified differently in the ETSA specification the requirement is:

A PLEC project One spare conduit forallof the low voltage circuits

One spare conduit forallof the high voltage circuits up to

and including 300mm2.

One spare conduit per phase for any 630mm2 high voltage

installation

A Customer project ( ie, through any easement)For every 3 conduits (or part there of) installed that are to be occupied by

cables, there is one additional conduit included in the installation.

As an example,

There are 3 cable circuits installed in conduits made up of 2 low voltage

circuits in 2 x 80mm (or 100mm) conduits and one 300mm2 high voltage

cable with one phase installed in a each of 3 x 80mm conduits.

Note: Any public lighting cable installed in a medium or heavy duty conduit

is excluded from the requirements of 5.2.2

There are a total of 5 conduits with cables. With a requirement of one spare

conduit per 3 occupied conduits, or part thereof, there will need to be 2

additional conduits included in the installation.

5.2.3. Road crossings

There is a requirement for spare conduits as well as the conduits that are to be

utilised at the time of the cable installation at road crossings. Refer to section

4.2 of this standard for details.

5.3 Spare Conduit and Bend Requirements


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The requirement for bends will need to be assessed at the time of installation as well

as at the time of trench design layout.

5.4 Conduit Sizes

While the chart specifies minimum conduit sizes, a larger conduit may be installed on

the proviso that the conduit can be made continuous with any existing or future

continuous conduit installation.

A conduit of a higher classification can be utilised then those specified.The minimum size of a conduit for a specific cable size are as follows:

Cable Circuit Conduit Size Conduit Bend

LV Main & Service

bundled

1 x 80mm VLD 1800 radius, Light duty

HV 35mm2 1 x 80mm VLD 1800 radius, Light duty

HV 95mm2 1 x 100mm VLD 1800 radius, Light dutyHV 300mm2 and

630mm2

3 x 80mm VLD 1800 radius, Light duty

Public Lighting 1 x 32mm HD 312 radius, Heavy duty

CBD installation No x 125mm VLD

The ETSA standard class 4.5 is equivalent to very light duty (VLD)

The ETSA standard class 6.0 is equivalent to light duty (LD)

Care must be taken in joining conduits. Different grades have different internal

diameters and the resultant raised internal edge has the potential to damage the outer

layer of cable during cable pulling.

5.5 Compliance to Australian Standard

Conduits and couplings shall be uPVC material and meet the requirements of AS/NZS

2053 Parts 1 and 2 for Rigid Plain designation. The conduit will be marked with the

word electrical, the conduit size and class, eg ELECTRICAL DUCTING 100 mm

4.5 class. No other form of rigid conduit is permitted without the approval of the

Network Standards Manager .


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c)be light orange in colour. Black conduit with orange stripes may be utilisedwith the approval of the project officer if orange conduit is not available.

d)be of size and characteristics to allow the cable to achieve its current rating.e) Be anchored at conduit entry/exit appropriately to maintain its horizontal

profile. The polyethelyne material has a memory and will attempt to coil

up. This will introduce stress at conduit transition locations and at the

start/end of a directional boring conduit installation.

5.8 Design of Conduit Installation

Conduit designs shall be prepared to ensure that pulling tensions do not exceed the

maximum permissible as required by the Construction Standard TS 087.

Installation details and techniques for cable pulling through conduits are in E1906.

Reference to an indication of cable pulling tensions is listed in E1910 sheet 4.2

5.9 Conduit Installation

Conduits shall be laid on an evenly bedded 50mm thick layer of well-graded sand

b i ll f f l d i l h i di i i f 6

Floor of trench /opening for bore

Edge ofentry/exithole

Securing the end of directional boring conduit

Directionalboring conduit

End of polyethylenepipe to be concreteencased orsandbagged


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For spare conduits in a group, the position of the ends shall not vary by more than

300mm. Where conduits are installed in layers, the ends shall be positioned

horizontally.

Conduits between new and existing subdivisions must be joined together.

Cable markers are required wherever ETSA conduits/ cables pass through private

property. Refer to E1979 for installation details.

5.10 Sealing of Conduits

For a cable Installation

Where cables have been installed in conduits, a conduit end shall be adequately sealed

to prevent the entrance of dirt, stones, white ants and moisture into the conduit by the

use of polyethylene expanded foam applied in accordance with the manufacturer's

instructions.

The expanding foam should not encroach into the conduit any further then 75mm.This will ensure that the foam/cable can be easily removed if the need arises.

Sealing of conduits with cables

For conduits with no cables

The use of end caps is a requirement for any conduit that is to remain vacant. This

includes the installation of end caps on a temporary basis on a conduit that will not

have a cable installed immediately.

Description Stock Item NoCap, push on 40mm for consumers conduit

Cap, push on 50mm for consumers conduit NC 6462

Cap, push on 80mm NC 6470

Cap, push on 100mm NC 6501

Scrunched plastic ornewspaper

Cable

Approx 75mm

Expanding foam


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Diagram C Install cables buried direct at a depth of 1000 mm. Spare conduits as

section 5 are required for the cable circuits that are to be installed. Polymeric cover

slabs are still to be installed. Warning tape is required in all cases.

The general trench configuration shall be in accordance with the following diagrams.

50mm

BEDDING

SANDPL LV Spare HV

200 mm

maxm

WARNING

TAPE

50mm

1000mm

50mm

750 mm

minm.

BEDDING

SAND

P/L LV Spare HV

POLYMERIC

COVER SLAB

50mm

75mm

maxm

Diagram A cable in conduit at 1000 mm Diagram B Cable in conduit at 750mm

750 mm

minm

1000 mmPOLYMERIC

COVER SLAB

5mm thick

50mm75mm

maxm

Diagram C

Cable buried direct

N t


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Spare conduit

Cables buried direct

Public lighting can be

in conduit or buried

direct

50mm

1000 mmBEDDING

SAND

50mm

750mm

Notes

Refer section 4.1

ROAD VERGE -

SINGLE CUSTOMER

Any ETSA cable system that needs to be located under a road needs to satisfy either the

requirements detailed in section 4.5. for common service trenches or section 4.3 if it is a

Transport SA road

In situations where public lighting circuits within conduits are to be located in a trench

alone, (eg no adjacent power circuits or spare conduits), the minimum cover shall be

600mm with warning tape installed at 400 mm.

Any public lighting network that is a Customer Lantern Energy Rate (CLER) or is fed

from a metered supply point requires a minimum separation of 150mm from any

ETSA infrastructure.

8.0 EXCAVATION FOR VAULTS

The excavation for vaults shall be as follows:

(a) Padmount Transformer Vaults:

the dimensions are in the order of 1850 long x 1000 wide x 1250 deep, totalling

approximately 2.5 m of spoil to be excavated.

(b) Switching Cubicle Vaults:

the dimensions are in the order of 2250 long x 1000 wide x 1175 deep, totallingapproximately 2.7 m of spoil to be excavated.

The spoil requiring excavation for the above two cases allows working room for

the placement of cables in conjunction with installation of the vaults.


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Some common sand types are designated as DS4B and PM64. The specification for these

types differs from the ETSA standard. It is the contractors responsibility to ensure the

installed sand meets the ETSA specification.

TEST METHOD TEST PERMITTEDTEST VALUES

Grading Percent Passing

AS1141.11 Sieve Sizes mm

AS1152 4.75 100

2.36 98 - 100

1.18 94 - 100

0.6 85 - 100

0.425 55 - 100

0.3 25 - 100

0.15 5 - 40

0.075 0 - 10

AS1289 C3.1 Plasticity Index Maximum 6

(non plastic)

10.0 POLYMERIC CABLE COVERS / MARKER TAPE

The stock item for the 5mm polymeric cable cover is RN 0202 which is supplied as a

15 metre long roll, 300mm wide. To satisfy AS/NZS 3000 the strip must be placed no

more than 75mm above ETSA infrastructure and must overlap the ETSA

infrastructure by 40mm per side.

Marker tape is a requirement for PLEC projects. For any other installation, if the

conduits installed for electrical infrastructure are not a light orange in colour, marker

tape will be required to be installed not more then 200mm above the conduits. If

polymeric cable covers have been installed marker tape is not a requirement


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Backfilling material must be clean and completely free from all fibrous and vegetable

matter and other material which may attract or be attacked by termites.

Excavated material from the trench may be used as backfill above the bedding sandprovided that this material is predominantly soil. If the material does contain any

metal or rocks, then it may only be used if :

the amount of metal and rocks is less than 20% of the material (by volume)

the metal and rocks pass through a 50 mm screen.

Where conduits are laid beneath other buried services, the backfill beneath suchservices is adequately compacted such that :

(a) no voids between conduit layers, and

(b) the other buried service(s) is adequately supported to prevent damage.

Consolidation of the backfilled excavations will be in accordance with the local

Council or Transport SA specifications as appropriate.

12.0 CIVIL WORKS

12.1 Applicants Responsibilities

The Applicant or an agent of the applicant shall be responsible for:

Ensuring that all allotment pegs, including any replacement pegs, easementpegs and level pegs are correctly placed, clearly visible, and numbered to

show allotment numbers, reserves, easements etc.

Carrying out and co-ordinating all the pegging, trenching, backfilling,reinstatement, levelling, and associated work including retaining walls,

necessary for the installation of cables, transformers and switching stations,

service pits and pillars and lighting columns.

The safety of the open trench and any liability arising from the Applicant'sworks. This includes ensuring that there is suitable clearance between any

excavation and existing ETSA infrastructure, including poles and footings. A

financial penalty can be applied by the industry Regulator for any unlawfull

interference


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Damage caused to vaults and associated equipment during backfilling andcompaction

13.0 CONTAMINATED SOIL

Where ETSA Utilities constructs the Works, it is the Applicant's responsibility to

ensure that the soil is free from any contaminants that may be a risk to the health of

ETSA Utilities distribution workers. Written assurance may be required to

demonstrate that the soil is free from contamination and if necessary a report detailing

known contamination and steps taken to alleviate the health risks. Further testing may

be required before ETSA Utilities agrees to work on the site.

14.0 CIVIL WORKS COMPLIANCE

Part of ETSA Utilities regulatory requirements includes an undertaking that any

electrical installation is compliant. Civil works and conduit installation forms a part of

the ETSA electrical asset and must be at a standard that satisfies all of the relevant

ETSA Utilities standards and specifications.

To assist in the verification that the civil works are to standard a Civil Work

Compliance form is required from the civil contractor as part of the electrical

compliance.

There is a spreadsheet that details responsibilities for both the Civil Works

Notification form and the Civil Works Compliance form in appendix A of this

specification.

14.1 Civil Works Notification

Civil works form a component of the asset inspection and vesting process. The Civil

Works Notification form NICC-453 (refer to sect 15.0 for access to the form) must be

submitted to the appropriate ETSA Utilities representative. The following notice is

required:A section (contestable projects) 10 working days notice

B section 5 working days notice

14.2 Civil Works Compliance


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www.etsautilities.com.au for external users. Open services/business services/Network Information

Any ETSA Utilities employee has access via the Intranet index and opening upNetwork/Quality Management Systems/Network Information.

Some of the information that is relevant to this technical standard include the

following;

Civil Contractors Utilised by ETSA Utilities - NICC-203

For a TSA road: The Notification of Works Impacting SA Roads - NICC-251

For a railway line: Application to Cross Railways With Electric Power CablesNICC-252

Civil Works Notification form NICC-453

Civil Works Compliance form NICC-452

Terms & Conditions for Network Installation by a Contractor

Trenching & Conduit Standard Technical Standard TS 085


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Trenching & Conduit Standard Technical Standard TS - 085

Issued: April 05 TS -085 Authorised: J Ali 11/04/05 Appendix A

CIVIL WORKS NOTIFICATION & COMPLIANCE RESPONSIBILITY

CaMS / BSO

(minor works only)

CaMS / ContractSvisor (minor &

major project)

CPO

(major projects only)

Customer (whenresponsible for

trenching)

Civil Contractor

Civil Works notification form NICC - 453 Intranet: Network/QMS/Network Information

Customer doing thetrenching

1. Fill in B:Contract Supervisor/ TSW8

2. Issue to customer

1. Insert point ofcontact:Compliance Co-ord

2. Issue to customeras part of

information pack

Customer to forwardform to the contractedcivil contractor

Return form to:A for a contestable

projectB for all other projects

(Contract

Supervisor / TSW8)

ETSA doing thetrenching

1. Fill in B:Contract Supervisor/ TSW8

2. Issue to civilcontractor

Return form to:Contract Supervisor/ TSW8

Civil Works Compliance form NICC - 452 Intranet Network/QMS/Network Information

Customer doing thetrenching

1. Insert name ofContract Supervisor/ TSW8

2. Issue to customer

1. Highlight point ofcontact as electricalcontractor

2. Issue as part ofinformation pack

1. Customer to insertelectrical contractordetails

2. Forward form tocivil contractor

Return form to:Electrical contractor.If unknown, thecustomer

ETSA doing the

trenching

1. Fill in ETSAContract Supervsor/ TSW8

2. Issue to civilcontractor

Return form to:Electrical contractor.If unknown, Contract

Supervisor / TSW8

Note: The Civil Works Compliance form must be completed for all projects with a trenching component as

it is a prerequisite to acceptance of the Certificate of ETSA Utilities Electrical Compliance

Trenching for Underground Cables

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