Distribution Standard

DISTRIBUTION STANDARD

REFERENCE REVSCSASAAM2 4

TITLE: DISTRIBUTION STANDARD DATE: MAY 1998PART 3: LOW-VOLTAGE RETICULATION PAGE 1 OF 56SECTION 1: LOW-VOLTAGE REVISION DATE:OVERHEAD RETICULATION MAY 2001

TESCOD APPROVED DOCUMENTJune 1998COMPILED BY FUNCTIONAL RESP. APPROVED BY AUTHORIZED BYSigned............................I FergusonDT Design

Signed...............................I FergusonESC

Signed.............................P Crowdyfor TESCOD

Signed.............................P J MarogaDTM for ED (D)

ContentsPage

Foreword........................................................................................................................................ 3

Introduction .................................................................................................................................... 4

1 Scope ........................................................................................................................................ 5

2 Normative references................................................................................................................ 5

3 Definitions and abbreviations .................................................................................................... 7

4 Requirements ............................................................................................................................ 8

4.1 Reticulation methods...................................................................................................... 84.2 General........................................................................................................................... 164.3 Layout design options..................................................................................................... 164.4 Requirements for bare wire and ABC systems .............................................................. 164.5 Minimum conductor clearances (in span) ...................................................................... 224.6 Telkom conditions for sharing of services ...................................................................... 234.7 Protection ....................................................................................................................... 254.8 Transformers and surge arresters.................................................................................. 264.9 Earthing installation and tests......................................................................................... 284.10 Poles and stays .............................................................................................................. 264.11 Service connections ....................................................................................................... 294.12 Customer installations .................................................................................................... 294.13 Customer metering......................................................................................................... 29

DISTRIBUTION STANDARD REFERENCE REVPART 3: LOW-VOLTAGE RETICULATION SCSASAAM2 4SECTION 1: LOW-VOLTAGE OVERHEADRETICULATION

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Contents (continued)Page

4.14 Drawings......................................................................................................................... 304.15 Bills of materials (BOM).................................................................................................. 304.16 DT Project ...................................................................................................................... 304.17 BMS codification............................................................................................................. 304.18 Marking and labelling...................................................................................................... 30

5 Tests and commissioning.......................................................................................................... 31

Annexes

A Conductor properties................................................................................................................. 32

B Design spans for bare neutral ABC systems ............................................................................ 35

C Design spans for ACSR bare wire systems .............................................................................. 36

D Design spans for AAAC bare wire systems .............................................................................. 37

E Urban reticulation ...................................................................................................................... 38

F Reticulation — Inspection sheet................................................................................................ 39

G Electrical test record sheet ........................................................................................................ 48

H BMS codification structure using the DT project tool ................................................................ 49

J List of drawings ......................................................................................................................... 50

H Bibliography............................................................................................................................... 55

L Revision information.................................................................................................................. 56


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Foreword

The Distribution Standard is a multi-part document whose total structure is defined in Part 0. This partof the Distribution Standard consists of the following sections under the general title: Low voltagereticulation:

Section 1: Low-voltage overhead reticulation.Section 2: Low-voltage underground reticulation.Section 3: Low-voltage protection philosophy.Section 4: Low-voltage protection philosophy for low consumption areas..

Any recommendations for corrections, additions or deletions to this standard shall be sent to:

The Design ManagerDistribution TechnologyPrivate Bag X1074GERMISTON1400Telephone (011) 871-2416Fax (011) 871-2352Internet:CrowdyPH@DT_FS1Profs A96002


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Introduction

This section of the Distribution Standard has been prepared to establish specifications for and promotethe use of standardized designs, structures and materials for low-voltage (LV) overhead distributionsystems.

The intention behind the production of the standard is that all Eskom LV overhead distribution systemswill be built using standard designs as specified in the standard. The standardized materials are fullyspecified in SCSASAAM0, Distribution Standard, Part 9: Buyers Guide.

Some drawings mentioned in the text are not listed in the “List of drawings” annex. These drawingsare identified by a part number in brackets after the drawing number. The part number refers to thePart of the Distribution Standard in which the drawings can be found. For example (Part 9) refers toPart 9: Buyers guide.

It is important to note that the electrical planning, the physical layout of the reticulation equipment andproject management activities ultimately determine the cost of the electrification. Particular attentionmust be given to these areas so that the optimum use of standard products is achieved.

Electrical reticulation design that incorporates electrical planning and physical layout of equipment is athought provoking process that must not be unnecessarily constrained.


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1 Scope

This section of part 3 of the Distribution Standard covers the construction of bare wire and insulatedconductor overhead LV reticulation systems using either wood or concrete poles. These systems arenormally fed from MV/LV transformers and are used to supply individual customers at LV.

It covers three overhead low-voltage reticulation methods, namely single-phase (2 wire), dual-phase(3 wire), and three-phase (4 wire). These methods provide the reticulation designer with the bestknown options to achieve cost effective reticulation for most electrification areas in South Africa.

The three methods use similar materials and construction techniques. Where appropriate, bare andinsulated systems and certain combinations of the three methods above can be used to achieve costeffective reticulation.

Transformers feeding the LV overhead lines are generally pole-mounted (first choice for electrificationand smaller transformers) but ground-mounted units can also be used, where circumstances and sizedictate.

This standard will be required to change continually as Eskom strives for continual improvements to itsstandards. Users of this standard are thus required to establish the precise requirements of the localOperating Divisions. They will provide the necessary guidelines to enable reticulation designs to befrozen at the desired point in a project to prevent the continual change from interfering with the projectand its associated costs.

The local change control forum enables the local area to cope with continual change to standards whileprogressing with the projects.

2 Normative references

The following standards contain provisions that, through reference in the text, constitute provisions ofthis standard. At the time of publication, the editions indicated were valid. All standards are subject torevision, and parties to agreements based on this standard are encouraged to investigate thepossibility of applying the most recent editions of the standards listed below. Information on currentlyvalid national and international standards may be obtained from the South African Bureau ofStandards. Information on valid Eskom standards and software tools is available from DistributionTechnology, 011-871-2448(ph), 011-871-2353(fax), Email Coghlaha@DT-FS1

SABS 0142:1993, The wiring of premises.

SABS 780:1979, Distribution transformers.

SABS 1524-1:1994, Electricity dispensing systems — Part 1: Single-phase electricity dispensers.

SABS 1619:1995, Small power distribution units (ready boards) for single-phase 230 V serviceconnections.

NRS 016:1995, Electricity distribution — Code of practice for the earthing of low-voltage distributionsystems.

NRS 032:1993, Electricity distribution — Service distribution boxes — Pole-mounted types foroverhead single-phase a.c. service connections at 230 V.

NRS 041:1995, Electricity transmission and distribution — Code of practice for overhead power linesfor conditions prevailing in South Africa.


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NRS 043:1997, Code of practice for the joint use of a pole route for power and telecommunicationlines.

DTC 0106, Specification for concrete poles (reinforced, partially pre-stressed and pre-stressed types).

ESKASAAN0:Rev.0, Standard for the labelling of high voltage equipment.

SCSAGAAF5:Rev.1, Distribution standard — Part 3: Low-voltage reticulation — Section 3: Low-voltage protection philosophy.

SCSAGAAH8:Rev.0, Distribution standard — Part 3: Low-voltage reticulation — Section 4: Low-voltage protection philosophy for low consumption areas.

SCSAGAAI2:Rev.0, Design notes for single- and dual-phase reticulation.

SCSASAAL9:Rev.1, Distribution standard — Part 2: Earthing: Section 1: — MV and LV reticulationearthing.

SCSASAAM0:Rev.0, Distribution standard — Part 0: Structure, definitions, abbreviations andexemptions.

SCSASAAP1:Rev.0, Distribution standard — Part 4: Medium-voltage reticulation — Section 1:Overhead reticulation.

SCSASAAS3:Rev.0, Distribution standard — Part 8 Services: Section 1 - Electrification.

SCSPVAAT6:Rev.0, Distribution standard — Part 9: Buyer’s guide.

SCSSCAAD5:Rev.2, Aerial bundled conductor with uninsulated (bare) neutral.

SCSSCAAD7:Rev.5, Specification for wood poles, cross-arms and spacer blocks.

SCSSCAAH4:Rev.1, Specification for oil-immersed power transformers to 2 MVA and 22 kV.

SCSSCAAL4:Rev.0, Fittings for bare neutral aerial bundled conductor.

SCSSCAAO1:Rev.0, Specification for stay and pole planting stay and pole compacting andcompaction testing for medium-voltage and low-voltage lines. (Draft).

TRR/E/96/ELI68, Large single phase motors (TRI Report).

Tools

• Pre-electrification research tool• Electrification technology cost estimator (ElecTech)• DT V-Drop 7

PEN 70/005:Rev.0, Decommissioning of Northern Engineering Division Capital Assets.

ACP 60

3 Definitions and abbreviations

The definitions and abbreviations in SCSASAAM0 and those listed below apply to this part.


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3.1 Definitions

3.1.1 balanced system: A dual- or three-phase system where all phase conductors are carrying asimilar load. The neutral return conductor carries little or no current.

3.1.2 LV dual-phase: A 50 Hz a.c. supply at 230 V r.m.s. phase-to-neutral. 460 V r.m.s. phase-to-phase (180� vector phase displacement). Note the difference to two-phase supply.

3.1.3 LV single-phase: A 50 Hz a.c. supply at 230 V r.m.s. phase-to-neutral. The neutral carries thefull load current.

3.1.4 LV three-phase: A 50 Hz a.c. supply at 230 V r.m.s. phase-to-neutral; 400 V r.m.s. phase-to-phase (120� vector phase displacement).

3.1.5 MV phase-to-phase: Any two phases of a three-phase MV supply. An unbalanced three-phaseMV supply. (This is not a recommended method but it is obtained as a result of using two phases of athree-phase system. It appears here to ensure that it is not confused with dual-phase).

3.1.6 MV single-phase: A 50 Hz a.c. supply at 12,7 kV r.m.s. phase-to-neutral. The neutral whichoriginates from the source transformer, carries the full load current.

3.1.7 MV three-phase: A 50 Hz a.c. supply at 12,7 kV r.m.s. phase-to-neutral; 22 kV r.m.s. phase-to-phase (120� vector phase displacement).

3.1.8 single wire earth return: A 50 Hz a.c. supply at 20 kV r.m.s. phase-to-earth. The returncurrent is through the general body of the earth.

3.1.9 unbalanced system: A dual- or three-phase system where the phase conductors do not carry asimilar load. The neutral return conductor carries a significant current.

3.2 Abbreviations

3.2.1 ABC: Aerial bundled conductors.

3.2.2 SWER: Single wire earth return.


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4 Requirements

4.1 Reticulation methods

4.1.1 Introduction

The practice of three-phase MV and LV reticulation is sometimes not the most cost effective method ofelectrification. The use of MV philosophies like SWER, single-phase and phase-to-phase systemscombined with LV philosophies like single-phase and dual-phase systems are often more appropriate,especially when dealing with small, dispersed loads.

This is mainly due to the fact that three-phase conductors may have a power transfer capability greaterthan that required by the load and the transformers and the conductors are not fully utilized.

The main cost advantages of the above methods are

a) SWER and two-phase MV systems could require shorter poles or can provide longer span lengthsthan three-phase designs when using the same height poles,

b) SWER and two-phase MV systems require less pole-dressing equipment,

c) single-phase and dual-phase transformers are less costly than three-phase units, and

d) single- and dual-phase LV ABC can be spanned up to 30 % further than three-phase ABC.

There are some possible disadvantages of these methods and these are

a) obviously traditional three-phase LV supplies are not available but a three-phase supply can becreated using power electronics. Refer to TRI report TRR/AE/96/ELI68 “Large Single PhaseMotors”,

b) if there is sufficient motivation to upgrade an area to three-phase supply the customers wouldexperience outages on these networks to enable the upgrade, and

c) unbalance could limit transfer capabilities however this is not expected to have an undesirableeffect on electrification projects. Unbalance issues are being investigated at present.

The three-phase, dual-phase and single-phase LV reticulation methods are described in figures 1,2and 3.


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4.1.2 Three-phase system

Figure 1 — Three-phase LV system

4.1.3 Dual-phase system

22 kV/460V ( 230V ∠ 180�, 230V ∠ 0� ).

Figure 2 — Dual-phase LV system

400V

RED

WHITE

BLUE

NEUTRAL

L N

E

DOMESTICSUPPLYPOINT

3 phase MV

Note separateneutral & earthin customersdwelling

N + E

+ 230V - 230V

PHASE 1

NEUTRAL

PHASE 2

L N

E

DOMESTICSUPPLYPOINT


N + E

3 phase orph-ph MV or SWER


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4.1.4 Single-phase system

Figure 3 — Single-phase LV system

Table 1 — Combinations of MV and LV for various methodologies

1 2 3 4

LV methodology MV options Transformer options LV cable options

Three-phase Three-phase 50 kVA & 100 kVAThree-phase16 kVA single-phase32 kVA dual-phase

ABC or bare wiretwo-wire, three-wire or four-wire

Dual-phase Three-phase, Ph-PhOR SWER

32 kVA dual-phase forSWER or ph-ph

ABC or bare wirethree-wire and two-wire

Single-phase Three-phase orph-ph

16 kVA single-phase ABC or bare wiretwo-wire

NOTE — 25 kVA single-phase transformers can be negotiated for certain projects depending on the circumstances.

4.1.5 Mixing of technology options

Clauses 4.1.2, 4.1.3, 4.1.4 and table 1 give the various options available for mixing methods on aparticular project or reticulation system. It is important to mix the methods in a manner that ensuresthe best overall electrification solution, for example, because of the marginal difference in cost betweentwo-wire and three-wire 35 mm² ABC it would not make sense to mix the two if significant cost benefitwas not evident. On the other hand an electrically sound design using a mix of four-wire and two-wireABC would generally show significant cost savings.

Also note that the combination of bare wire and ABC systems in a particular transformer zone isallowed and encouraged provided that the overall reticulation criteria are met.

These issues shall be discussed with and agreed to by the Operating Divisions.

230V PHASE

NEUTRAL

L N

E

DOMESTICSUPPLYPOINT


3 phase or

ph-ph MV or

SWER

N + E


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4.1.6 Planning factors

The following clauses attempt to highlight certain planning issues.

4.1.6.1 Pre-electrification research and technology options

A pre-electrification survey using the Pre-Electrification Research Tool (Elec. Tech) shall be carried outon most projects.

The Electrification Technology Cost Estimator (Elec. Tech) tool shall be used do a “first pass MVplanning and costing analysis”, especially to select the most cost effective technology for a given area.

This tool is most effective for estimating technology costs for whole electrification areas in which bulksupply lines and reticulation designs are needed.

If phase-to-phase or SWER MV and dual-phase or single-phase LV provide the right technology fit anda customer requests a three-phase supply point, one shall consider various options before changing tothree-phase technology e.g. does the customer actually need three-phase supply?

In most cases a three-phase supply point is not necessary for the application required. In almost allcases it is much more cost effective to supply a single-phase point and install a load that will run on thesingle-phase supply. For example, single-phase motors up to 7,5 kW are readily available (e.g. GECmotors). Loads that can be serviced by motors of about 3 kW include

a) pumps,

b) commercial and industrial coolers and freezers,

c) mortuary rooms,

d) 4-post car hoists, and

e) miscellaneous garage equipment.

For motor loads greater than 7,5 kW, written pole and other single-phase motor types are available.

Note that modifications or adjustments to the customer equipment may be required.

4.1.6.2 Load balancing

On both three-phase and dual-phase LV systems, balancing two-phases per node (pole-top box) forcustomer connections will result in the minimum number of nodes to achieve load balancing.

This is difficult in practice due to the customer layouts, particularly on rural reticulations. The Eskomstandard pole-top box (node) is only equipped for connection to a single-phase supply for this reason.

On projects where the balancing of two phases per node is needed two options exist, depending on thecircumstances.


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Option (1): Layouts where most nodes will only have enough customer connections for a single-phaseconnection.

a) Use a single, standard pole-top box that has a single-phase connection for most nodes.

b) Use two single pole-top boxes for those nodes that can be balanced on two phases, asappropriate.

Option (2): Layouts where most nodes can be balanced by using two phases.

Specify the pole-top box for two-phase connections. The specification allows for this option.


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The diagrams in figure 4 illustrate the differences between balancing with one or two phases per node :

Figure 4 — Load balancing

ph1 ph1

ph1ph1

ph2 ph2

ph2ph2

ph3 ph3

ph3ph3

ph3 ph3

ph3ph3

ph2 ph2

ph2ph2

ph1 ph1

ph1ph1

Balanced three-phase LV phase connection — Single-phase per node

ph1 ph1

ph1ph1

ph3 ph3

ph3ph3

ph2 ph2

ph2ph2

Balanced three-phase LV phase connection — Two-phases per node

ph1 ph1

ph1ph1

ph2 ph2

ph2ph2

ph2 ph2

ph2ph2

ph1 ph1

ph1ph1

Balanced dual-phase LV phase connection — Single-phase per node

ph1 ph1

ph2ph2

ph1 ph1

ph2ph2

ph1 ph1

ph2ph2

ph1 ph1

ph2ph2

Balanced dual-phase LV phase connection — Two-phases per node


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The following vector diagrams indicate the different types of networks:

NOTE — In all practical situations unbalance will exist giving rise to neutral current. The prime objective is to design forminimal unbalance. Balancing of a dual-phase system is easier than a three-phase system as only two phases areunder consideration.

Figure 5 — Vector diagrams

Balanced three-phase LV network withneutral voltage drop = 0

Three-phase network with only onephase loaded, equivalent to a single-phase system or a two-phase LV systemwith only one phase loaded

Balanced dual-phase LV network with neutralvoltage drop = 0 (180° between the phases)


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4.1.6.3 Voltage drop

Voltage drops experienced with the various technology options are evaluated in SCSAGAAI2.

The power transfer capability ratios of the three-phase, dual phase and the single-phase methods areas follows:

Three-phase Dual-phase Single-phase

6 4 1

This means that the balanced three-phase method is 6 times more efficient in transmitting power thanthe single-phase method and the dual-phase method is four times more efficient in transmitting powerthan the single-phase method. Use of DT Vdrop will verify the optimum methodology for anyelectrification design.

4.1.6.4 Upgrade paths

A separate document to discuss upgrade paths is planned as upgrading mostly concerns MV & LV.

Eskom has introduced a philosophy into electrification design that requires the networks to beappropriate for the customer base. This means that a certain amount of information is needed aboutthe customers in order to design appropriate networks after considering the load for the first 5 years,then 10 years and 20 years. Planning guidelines in support of the philosophy are obtainable from thePlanning functions in the Operating Divisions. Full advantage needs to be taken of delaying capitalexpenditure whilst considering the customer needs. The philosophy thus needs to be supported by anUpgrade Guideline, the main points of which are indicated in table 2:

Table 2 — Upgrade paths

1 2 3

Existing network Reason for upgrade Upgrade optionsThree-phase MV feedingthree-phase LV

1 LV voltage drop too high2 Transformer overload3 Combination of above

1.1 Add extra conductor or increaseconductor size

1.2 Reduce LV line length by extending MVand adding transformers

2.1 Increase transformer size or create twotransformer areas from one as above

2.2 Suitable combination of aboveThree-phase MV feedingsingle-phase LV


1.1 Bare wire-Convert to three-phase ordual-phase by changing transformer andadding extra conductor

1.2 ABC-Convert to dual-phase by changingtransformer and adding one more ABCconductor

2.1 Change transformer2.2 Suitable combination of above

Phase-to-phase or SWERfeedingsingle-phase LV


1.1 Bare wire-Convert to dual-phase bychanging transformer and adding extraconductor

1.2 ABC-Convert to dual-phase by changingtransformer and adding one more ABCconductor

2.1 Change transformer2.2 Suitable combination of above


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Table 2 (continued)

1 2 3

Existing network Reason for upgrade Upgrade optionsPhase-to-phase or SWERfeeding dual-phase LV


1.1 Double circuit dual-phase1.2 Reduce LV line length by extending MVand adding transformers2.1 Increase transformer size or create twotransformer areas from one as above2.2 Suitable combination of above

It is generally not necessary to upgrade phase-phase MV and SWER to three-phase. This situationmay arise in the event of a special load being required. This situation needs to be treated on its merits.

4.2 General

4.2.1 The requirements of the Occupational Health and Safety Act, Act 85 of 1993 (OHS Act) and allsubsequent amendments and regulations shall be observed.

4.2.2 Factors of safety shall be as stated in the OHS Act except where exemption has been obtained.For exemptions see SCSASAAM0.

4.3 Layout design options

Radial LV systems are generally the most economical with conductor sections selected afteroptimization on DT-VDROP. There are a number of customer layouts that shall be considered whendoing an electrification design. These can be classified into two main layouts:

4.3.1 Structured or grid layout

Two acceptable LV reticulation designs for a structured/grid layout are as follows depending on thecircumstances:

a) between the stands in a block, (mid block) with spurs to poles for street lights where necessary;and

b) along the street frontage of the stands.

4.3.2 Unstructured (informal) or scattered layouts

The most appropriate reticulation design for this type of layout shall be used. LV layouts will bedependent on optimum transformer installation positions, accessibility and density of areas.

4.4 Requirements for bare wire and ABC systems

The two standard conductor types used by Eskom are

a) aerial bundled conductor (ABC) with uninsulated (bare) neutral, and

b) ACSR and AAAC bare conductors.


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ABC is generally accepted as the preferred option due to its simplicity of construction, minimalcomponents and its inherent long-term reliability. This is not true for all electrification areas and thereare also significant advantages in using bare conductors in some circumstances. Thesecircumstances will only become apparent when doing the detailed planning and design of electrificationprojects and each situation shall be treated on merit. A few common instances where bare wireconstruction may offer advantages are listed below

a) connection of widespread customers on the outskirts of a reticulation area, and

b) electrification of an area which could see significant growth and where ease of upgrade is a factor.

NOTE — Sag and Tension tables are not provided in this part and can be generated using the DT-Sat 95 tool availablefrom Distribution Technology, Simmerpan. A Sag and Tension book for all conductors is proposed for future use by fieldstaff.

4.4.1 LV ABC

4.4.1.1 The low-voltage ABC shall conform to SCSSCAAD5. The preferred conductor sizes are:

a) 3 � 70 mm² phase conductors + 50 mm² neutral (Bare) : three-phase (4-wire).

b) 3 � 35 mm² phase conductors + 35 mm² neutral (Bare) : three-phase (4-wire).

c) 1 � 35 mm² phase conductors + 35 mm² neutral (Bare) : single-phase (2-wire).

d) 2 � 35 mm² phase conductors + 35 mm² neutral (Bare) : dual-phase (3-wire).

4.4.1.2 LV ABC fittings shall conform to SCSSCAAL4.

4.4.1.3 LV ABC may allow for auxiliary supplies to street lights, traffic signals and other outlets. Wherespecified, auxiliary supplies of this nature are generally taken directly from a phase core. An additionalsupply core does enable more control of the apparatus connected to it, for example, control of groupsof streetlights from a set point on the reticulation. The use of the additional auxiliary supply core is nota specified Eskom standard when using ABC and shall be the exception and not the rule.

4.4.1.4 Phase cores are identified by indented or embossed numbers 1,2 or 3.

a) The neutral requires no identification as it is bare.

b) Single-phase ABC shall have the phase core marked ‘1’.

c) Dual-phase ABC shall have the phase cores marked ‘1’ and ‘2’.

d) Three-phase ABC shall have the phase cores marked ‘1’, ‘2’ and ‘3’.


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Table 3 — ABC core allocation for different reticulation methods

1 2 3 4

ABC Marking Nominalphase-to-phase

voltage

Nominalphase-neutral

voltageThree-phase 1 = White

2 = Blue3 = Red

400 V 230 V

Single-phase 1 = White orBlue orRed

N/A 230 V

Dual-phase 1= +VE2= -VE

460 V +230 V-230 V

Upgrading single-phase to dual-phase(both conductors havephase cores marked 1)

Original conductor + ve.Mark 2nd phase conductor, ateach pole, 2-ve using analuminium label stuck end toend around the core.

2-Ve

460V +230V-230V

NOTE — It is possible that LV ABC systems may have to be upgraded in the future tocompensate for unacceptable low voltage levels due to increased loads. Even though eachsituation needs to be treated separately some upgrade recommendations, applicable to ABC,are presented in section 4.1.6.4. In this unlikely event of upgrading single-phase lines to dual-phase lines, use an aluminium label as described above to identify the cores.

4.4.1.5 The service connections shall be distributed between the two or three phases as determinedby the electrical planning function.

4.4.1.6 The most effective method of LV distribution is usually several radial feeders from eachtransformer.

4.4.1.7 Design span and sag tables for LV ABC are given in annex B.

4.4.1.8 Clearances applicable to shared structures are given in table 4. Clearances applicable toshared structures are given in table 5. Examples are given on drawings D-DT-0348 and D-DT-0349.The maximum span that can be tolerated by Telkom shall be established from Telkom in the area.Accommodation of Telkom maximum spans can be achieved by doing the following:

a) MV poles at design span length with a LV pole between to accommodate LV and Telkomconductors; and

b) MV or LV poles at the Telkom span length, for example, 60 m.

Additional costs to accommodate Telkom shall be in accordance with the Eskom/Telkom agreement,specified in NRS 043.

4.4.1.9 Cable ties in accordance with D-DT-3075 shall be used to avoid loosening the bundle at allstructures including transformer structures. The general positions of cable ties are shown on therelevant structure drawings. Additional ties shall be fitted as required.

4.4.1.10 On all bare neutral ABC systems the neutral shall be insulated from the strain clamp to thetransformer connection with a UV protected covering. Refer to D-DT-3127.


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4.4.1.11 All ABC tails or ends shall be sealed using end caps.

4.4.1.12 As Eskom does not have a code of practice for the installation and use of ABC systems,Eskom depends to a large extent on the ABC manufacturers and the ABC fittings industry to providetraining in this field. It shall be the responsibility of the construction contractor to ensure that hisworkers have the required skills and that the manufacturer’s requirements are adhered to.

4.4.1.13 Only aluminium conductors shall be connected directly to low-voltage fuse units.

4.4.1.1 ABC to ABC and ABC to service connectors (refer to D-DT-0314)

a) Non-tension phase connections on ABC shall be made using a 95/35 - 95/35 IPC in accordancewith D-DT-3039 (Part 9)

b) Non-tension neutral connections on ABC shall be made using either:

1) one H crimp in accordance with D-DT-3019 (Part 9) per connection; or

2) two PG clamps in accordance with D-DT-3058 (Part 9) per connection.

c) The ABC shall be connected to the pole-top distribution box using either:

1) 35 - 95/6-25 IPC (refer to D-DT-3039 (Part 9)) for phase connections; or

2) H-crimp (refer to D-DT-3093 (Part 9) for neutral connections; or

3) 35-95 (PG)/6-25 (IPC) (refer to D-DT-3039 (Part 9)) for neutral connections; or

4) A PG clamp suitable for bi-metallic connections in a particular environment could be used inexceptional circumstances. The PG clamp specification and the authority to use it shall beobtained from the local Operating Division.

NOTE — The H-crimp is suitable for aluminium to copper connections only if, with the H-crimp verticallypositioned, the copper conductor is below the aluminium conductor and the crimp is performed with a toolcapable of exerting at least 10 tons and an ‘0’ die.

d) All workers performing crimp connections shall be certified as competent to do so by the projectconstruction manager.

e) Insulated neutral and bare neutral ABC systems.

Eskom has used both insulated neutral ABC systems and bare neutral ABC systems extensively inthe past, but has standardized on the bare neutral system. Insulated neutral ABC systems may beextended using bare neutral ABC in accordance with this standard.

The connector used for connection of the insulated neutral ABC to the bare neutral ABC is shownon D-DT-3039, (Part 9). Note that the connector is coloured white/cream to distinguish it fromother connectors.


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f) When upgrading ABC systems and when it is necessary to optimize customer connections on theABC run, it is better to leave the existing pole-top distribution boxes where they are and install newones at more desirable positions. This is to ensure that the ABC remains sealed against moistureingress.

g) Once an IPC connector has been applied to an ABC phase conductor (or any insulated conductor)it shall not be removed. The ABC insulation cannot be repaired by the use of grease and tapesand the ABC conductor and connector are best left as a system. Cut away phase conductors shallhave their ends sealed.

If the connection is in the wrong place leave it where it is and make a new connection at the desiredpoint.

4.4.2 Bare LV conductors

As with ABC systems, bare wire systems may be used for all the reticulation methods, i.e. three-phase,single-phase, dual-phase and their practical combinations.

The bare wire system has the following benefits; it is

a) easy to rebalance;

b) simple to apply and has good reliability; and

c) easy to fault-find and maintain.

From an initial cost perspective it is suited to rural, low-density application with site conditions that allowfor long spans. It is also appropriate when an easy upgrade path is desired for the area.

Some of the things to be considered when comparing ABC and bare wire systems are as follows:

a) bare wire systems will require more maintenance than ABC, the total cost (initial and operating)equalizes in about the tenth year and thereafter bare wire will cost more than ABC. (This was theresult of a study in KwaZulu Natal in 1990 and is a guide only);

b) a stricter earth to neutral clearance requirement (5,5 m) for bare wire systems;

c) more stringent safety requirements for bare wire systems; and

d) bare wire systems are less forgiving to poor initial installation practice than ABC.

The specific requirements for LV bare wire systems are as follows:

a) the conductors shall be arranged in a vertical configuration with the neutral conductor always beingclosest to the ground i.e. the lowest conductor;

b) where dedicated street lighting circuits exist that cannot be interchanged, suspended earthingdevices may be installed;


PAGE 21 OF 56

c) Connections

1) Bare wire to bare wire connections may be made with the bolted PG (type) clamps or otheracceptable crimping techniques i.e. the 4-point indent system, the Burndy system or H-crimps.

NOTE — H-crimps may be used for aluminium to copper connections provided that the copper is below thealuminium and the correct tool and die is used.

2) Bare wire to insulated conductor connections.

i) Bare wire (normally ACSR or AAAC) to ABC.

— An L-tap and insulated lug bolted combination may be used.

— A suitably sized PG/IPC connector may be used. (Refer to D-DT-3039, Part 9).

ii) Bare wire to insulated service box lead

— 35-95 (PG) / 6-25(IPC). (Refer to D-DT-3039, Part 9)

— H-crimp.

— A PG clamp suitable for bi-metallic connections in a particular environment may beused in exceptional circumstances. The PG clamp specification and the authority touse it shall be obtained from the local Operating Division.

d) All bolted clamps used for connections shall have non-oxide grease applied.

e) The pole service box shall be installed 300 mm below the neutral /earth conductor.

f) The service box leads shall be stapled to the pole using double pin clips (Concentric clips) (refer toD-DT-3039, Part 9)). Service boxes shall be installed on the side of the pole, i.e. at 90° to theinsulators or inline with the conductor.

g) The structure drawings show an eye-nut attached to the neutral hardware. This is to facilitate theservice connection at a higher attachment point and to obviate the need for additional pigtail bolts.

h) All nuts that are associated with insulator supports shall have nut retention paint applied.

j) All galvanized metal work that is cut on site shall have anti-corrosion treatment applied immediatelyi.e. cold galvanizing.

k) The phase and neutral conductor position on the poles shall be as follows for the single-, dual- andthree-phase methods.

Three-phase Single-phase Dual-phaseWhite Phase (W,B,R) Phase +veBlue Neutral Phase -veRed Nil NeutralNeutral Nil NilNB: Upgrading involves moving conductors to be inline with the above, or redoing theconnections to suit. Pre-energization tests to ensure correct connections are mandatory.

l) Upgrading


PAGE 22 OF 56

1) Where conditions allow, poles shall be installed at maximum spacing (100 m to 115 m). Phaseseparators shall be installed for spacing greater than 80 m. The spacing shall allow for futureintermediate installations thus the initial spacing shall be in multiples to allow for final spacingexceeding 40 m.

2) When upgrades occur, additional hardware is installed, conductors are run out, service boxesare reset and loads are balanced.

3) With the latest technology developments, more emphasis shall be placed on dual-phase LVnetworks and dual-phase transformers, with upgradeable backbones and lateral feeders placedas close to the load as possible so as to facilitate the use of 4mm² concentric service cable.

m) Standard conductors

1) ACSR : Squirrel, Fox, Mink, Hare.

2) AAAC : Acacia, Pine, 35, Oak.

n) Only aluminium conductors shall be connected to low-voltage fuse units.

4.5 Minimum conductor clearances (in span)

4.5.1 The minimum clearances for bare overhead conductors shall be in accordance with theOHS Act. These clearances are given in table 4.


PAGE 23 OF 56

Table 4 — Clearance (at maximum sag or swing as applicable)

1 2 3 4 5 6 7 8 9 10 11

Ground Above Above Along Across Across Telkom Buil Other

Outsidetowns

(m)

Insidetowns

(m)

Railwaysand main

roads

(m)

Townshiproads

(m)

Roadsparallel

withentry/exit(m)

Com-munalland

(m)

Privateproperty

(m)

Insula-ted

(m)

-dingsand

struc-tures

Powerlines

(m)MV24 kV12 kV7,2 kVLV bare wire420 V/230 VLV insulatedABC 420 V/230 VConcentric 230 V

5,25,15,0

4,9

--

5,55,55,5

5,5

3,33,0

6,46,36,2

6,1

5,15,1

5,55,55,5

5,5

4,74,7

5,55,55,5

5,5

3,53,0

5,55,55,5

5,5

3,33,0

5,55,55,5

5,5

3,32,5

0,90,90,9

0,6

0,20,2

3,03,03,0

3,0

3,03,0

0,90,80,7

0,6

0,60,6

An LV or Telkom pole position at a MV midspan is considered to be a separate structure, hence 3 m clearance required.NOTES1 Column 2 is the minimum clearance of conductor to ground outside built-up areas.2 Column 3 is the minimum clearance of conductor to ground inside built-up areas.3 Column 4 is the minimum clearance to railway lines and proclaimed roads.4 Column 5 is the minimum clearance to unproclaimed roads used by vehicles such as delivery vans and buses.5 Column 6 is the minimum clearance to ground where lines run parallel to any road used by vehicles and vehicle entries/exits to the road crossunderneath the line.6 Column 7 is the minimum clearance to ground in areas used by the community such as tracks or walkways.7 Column 8 is the minimum clearance to ground in an area owned by one owner.8 Column 9 is the minimum clearance to Telkom cable supported on the same structures.9 Column 10 is the minimum clearance to buildings and structures not forming part of the network, including a LV/Telkom pole installed midspanunderneath a MV line.10 Column 11 is the minimum clearance to other power lines excluding the conditions listed in column 9.

4.5.2 Sag and ground clearances shall be calculated using the conductor operating temperature andthis can be assumed to be 50 °C, unless the operating temperature is more than this value.

4.5.3 A minimum conductor temperature of 50 °C shall be used to determine clearances underconductor swing conditions. The swing angle shall be that corresponding to 500 Pa of wind pressure.These separation distances shall apply under all operating and environmental conditions.

4.5.4 ABC with a bare neutral is classed as a fully insulated system.

4.5.5 Conductive poles resistance to earth should be such that the pole does not become alive duringan earth fault. No further earthing is required on poles bonded to an LV neutral.

4.5.6 Whenever a part of an insulated conductor is bare at the structure (e.g. a bare terminal) then thebare conductor separation distances shall apply.

4.5.7 Bare conductor clearances above water shall comply with the clearances in table 3 unless theactivities taking place in the water (i.e. sailing, navigation, etc) require greater clearance to be used.

4.6 Telkom conditions for sharing of services

4.6.1 Clearances (minimum) for shared services

The minimum attachment spacing between Eskom and Telkom services are listed in table 5.

Table 5 — Attachment spacing


PAGE 24 OF 56

1 2 3 4

MV LV

Bare Insulated Bare Insulated

2 m 0,9 m 1,2 m 0,9 m

4.6.1.1 The minimum attachment clearance between an insulated power conductor and a Telkomconductor on the same structure or adjacent structures along the same reticulation route shall be0,9 m.

4.6.1.2 There are no restrictions on the Eskom conductor type as specified in this document.

4.6.1.3 Separation distances at attachment points are between the telecommunication cable and thelowest attachment point of the power conductor or the lowest attachment point of the servicedistribution box.

Table 6 lists the minimum Telkom clearances.

Table 6 — Ground clearance of telecommunication cables

1 2

Location of route Minimum groundclearance

1) Across non-electrified railways 6,10

2) Across any national road 6,50

3) Across abnormal provincial roads 7,50

4) Across other provincial roads 6,10*

5) Across other public roads 6,10

6) Across streets, roads other than (2), (3), or (4) above, or across privately owned railwaytracks in or near towns

5,50

7) Across private roads or railway tracks not in or near towns 4,90

8) Along streets (including midblock), roads or privately owned railway lines in or near towns. 3,70

9) Along country roads or railway lines, or over veld or private lands other than (10). 3,00

10) Over cultivated farm lands and across points of entry into cultivated lands. 4,90

* This may be reduced to 5,5 m subject to negotiation with provincial authorities.

4.6.2 Telkom and Eskom service conductors may be hung from the same attachment points on the4 m/5 m poles only if no electrical connection points exist on the pole top in question.

4.6.3 Conditions

4.6.3.1 The clearances in tables 4, 5 and 6 are mandatory and no deviation shall be permitted withoutthe written agreement of Telkom and the power supply authority.

4.6.3.2 Earth connection of conductive poles resistance to earth shall be such that the pole does notbecome live during an earth fault. No further earthing is required on poles bonded to an LV neutral.

4.6.3.3 Telkom employees are required to go through a basic training as specified in the Eskomtraining course before they can do work on power line structures.

4.6.3.4 Stay anchors shall be supplied by each authority where they deem it necessary.


PAGE 25 OF 56

4.6.3.5 All plans for residential areas electrification shall be submitted to Telkom in the prescribedmanner. (See EMR22 of the OHS Act). In view of the time factor involved in the submission andapproval of plans it is strongly recommended that the proposed layout be clearly shown on acceptableplans and discussed with Telkom Regional representatives in the earliest stage of the project.

4.6.3.6 Telkom will provide Eskom with a request for any shared circuits.

4.6.3.7 Eskom should only agree to sharing of circuits if Telkom’s contribution to the shared circuits isgreater than any additional Eskom expenditure to accommodate Telkom.

4.7 Protection

The requirements for protection of the low-voltage system are as follows:

4.7.1 The rating of the protective device applied at the transformer LV shall be chosen in order thatthe lowest possible phase-to-neutral fault level on an LV distributor will operate the device. In order toensure this :

a) LV distributors protected by CSP type circuit-breakers shall have a minimum phase-to-neutral faultlevel of 2 � the full load rating of the transformer; and

b) LV distributors protected by fuses shall have a minimum phase-to-neutral fault level of 1,6 � thefuse rating i.e. the conventional fusing of the fuse.

Where this cannot be achieved suitable fuses shall be applied down the line.

4.7.2 On bare wire LV systems the protective device applied at the transformer LV or any point downline shall ensure that the lowest possible phase-to-neutral fault level within its zone of protection willresult in a protection operating time of less than 100 s.

4.7.3 CSP type transformers have an internal oil immersed circuit-breaker that protects thetransformer against overloading. The circuit-breaker can also provide adequate protection of LV ABCdistributors if the full load rating of the transformer that it protects is less than 70 % of the full loadrating of the conductor.

Where 100 kVA or 200 kVA CSP transformers supply 35 mm² ABC and 70 mm² ABC this requirementis not always met, however the circuit-breaker will protect the ABC provided the LV distributor does notexceed the length specified in table 7:

Table 7 — Maximum protected lengths of ABC

1 2 3

Transformer Maximum recommended lengthof 35 mm² ABC

Minimum recommendedlength of 70 mm 2 ABC

100 kVA 250 m See 4.7.3

200 kVA Will not protect ABC 170 m

4.7.4 Transformers without internal oil immersed circuit-breakers shall be equipped with externalfuses using the following guidelines:

a) 16 kVA single-phase 1 � 80 A HRC fuse.

b) 32 kVA dual-phase 2 � 80 A HRC fuses.


PAGE 26 OF 56

c) 50 kVA three-phase 3 � 80 A fuses

d) 100 kVA three-phase 3 � 160 A HRC fuses

e) 200 kVA three-phase 2 � 3 � 160 A HRC fuses

The fuses will also provide adequate protection for the LV distributor if the fuse rating is less than thefull load rating of the conductor used for the LV distribution.

Where 100 kVA or 200 kVA transformers with 160 A fuses supply 35 mm² ABC this requirement is notmet, however the fuse will protect the ABC provided the LV distributor does not exceed the lengthspecified in table 8:

Table 8 — Maximum protected lengths of ABC

Transformer Maximum recommended length of35 mm² ABC

100 kVA 280 m

200 kVA 290 m

4.7.5 Service cables of the concentric type originate from a pole-top box that is equipped with a 50 AMCB. This will grade reasonably with the transformer protection and the customer’s installation.Overload protection of the service cable is provided by the load limiting function of the electricitydispenser (ED) or energy control unit (ECU).

Further details regarding the low-voltage protection philosophy are given in SCSAGAAF5 andSCSAGAAH8.

4.7.6 Where used, the ED is equipped with a single-pole isolator and the ready-board has 20 Astandard curve MCBs and an earth leakage unit (double-pole isolation). Alternatively the energycontrol unit (ECU) is equipped with an earth leakage unit only.

4.8 Transformers and surge arresters

4.8.1 Transformers

Transformers shall comply with the following:

a) Transformers can either be the completely self protected (CSP) type or the standard SABS 780type in accordance with SCSSCAAH4.


PAGE 27 OF 56

b) The preferred sizes for transformers are 16 kVA (single-phase), 32 kVA (dual-phase), and 100 kVA(three-phase) and 200 kVA (three-phase). The actual size will depend on the ADMD predicted forthe supply area and load platform. The time/overload capacity of the transformer shall beconsidered to ensure cost effective design and the full overload capability of the transformer shallbe used in estimating the number of customers / transformers for a specific ADMD.

c) All transformers shall be earthed in accordance with drawing D-DT-0627 in SCSASAAL9.

d) The transformer LV connection shall be made in accordance with drawing D-DT-0308 for CSPunits or drawing D-DT-0309 for the SABS 780 type.

The LV earth may be positioned at the transformer (preferred) or one span away on at least twofeeders. The choice will depend on the prevailing circumstances, however the MV and LV earths shallbe at least 5 m apart.

4.8.2 Surge arresters

An LV surge arrester shall be placed between the LV neutral bushing and the transformer tank toprotect the transformer during transient fault conditions. The connection shall be in accordance withD-DT-0308 for CSP transformers and D-DT-0356 for SABS 780 transformers.

4.8.3 LV connections and jumpers

Line taps shall be used to connect the LV conductor jumpers to the transformer neutral bushings. Up to3 � 70 mm2 ABC jumpers may be connected into one linetap, if more jumpers are connected insulatedlugs shall be used. Care shall be taken with the installation of the line-taps to ensure properconnection.

LV fuse unit

The LV fuse units shall be positioned in a way that facilitates ease of operation from ground level usinga link stick with the appropriate attachments. The units shall be placed below the LV conductor and theposition shall also allow for future LV units to be installed where upgrading of the network isanticipated. The transformer structure drawing D-DT-0309 indicates proposed fuse unit positions forup to 4 units. Typically, two LV feeders can be fed from one fuse unit.

LV jumpering

The LV jumpering shall be bunched together and neatly routed from the transformer bushings to the LVfuse units at right angles, where possible, to ensure a tidy appearance. The ABC shall not be bent in anarc with a radius of less than 200mm so that the entry point is not under stress. Sharp bends shall beavoided. In the case of a bare neutral conductor the neutral shall be covered with LPDE tubing, inaccordance with D-DT-3127, from the neutral bushing to the LV fuse unit. The jumpering shall berouted in such a way that it will not chafe against sharp objects. Cable ties can also be used to keepthe jumpering in position: stainless steel strapping is not recommended. A separate set of jumpers isrequired for each fuse unit. The neutral conductor shall bypass the fuse unit and shall not be broken.


PAGE 28 OF 56

LV surge arrester

The recommended location for the LV surge arrester is against the pole but the conductor to the surgearrester shall be kept to a minimum. The surge arrester will explode at the bottom should the powertransferred during a surge exceed the rating of the surge arrester. Therefore the surge arrestor shallbe positioned so that when the surge arrester operates, it will do so without damage to otherequipment, especially the jumpering and the LV fuse unit. It is important that the conductor to thebottom of the surge arrester is soft and flexible in order to assist operation.

LV feeder take off

The LV feeder shall be located at a position that maintains ground clearance from the transformer andMV network. Typically the attachment of the LV feeders shall be 300 mm below the transformer

4.9 Earthing installation and tests

Installation earthing and earth tests shall be carried out in accordance with NRS 016, andSCSASAAL9, with particular reference to D-DT-0627 in SCSASAAL9.

4.10 Poles and stays

Poles may be either wood or concrete. The preference of the local engineering area shall beestablished. Concrete and wooden poles of the same height are not inter-changeable withoutconsidering the stresses they can withstand. Poles shall be selected in accordance with SCSSCAAO1.

a) Safety factors

1) Wood pole structures shall be designed with a safety factor of 2,7 in the case of suspensionstructures and 4,5 in the case of strain structures.

2) Concrete poles are designed with a safety factor of 2 for both strain and suspension structures.

b) Specifications of pole lengths

1) Wood poles shall comply with SCSSCAAD7. Standard wood pole lengths are 5 m, 7 m, 9m,10 m, 11 m, 12 m and 13 m.

2) Concrete poles shall be manufactured in accordance with DTC 0106. The standard concretepole lengths are 4 m, 7 m, 9 m, 10 m and 11 m. The design drawings of standard concretepoles used are given in Annex J.

c) It can be cost effective for LV, MV, street lighting and telephone services to share poles. This shallbe undertaken whenever practical and appropriate. If MV and LV share the same structure then ataller pole shall be used with the LV connections at the same height above the ground as for LValone. Refer to D-DT-0335 and D-DT-0336 of SCSASAAP1.

d) Where conductive poles e.g. steel, are used, all conductive parts shall be bonded to the LV neutral.Concrete poles are considered semi conductive and do not need to be bonded to the LV neutral:

e) The planting depths of concrete and wood poles are specified in table 9;


PAGE 29 OF 56

Table 9 — Planting depths of equivalent concrete and wood poles

1 2 3 4 5 6

Concrete poles Wooden poles 55 MPa

Length Strength Planting depth Length Pole top Planting depth

m kN mm m mm mm

4 1 800 5 80 1 000

7 4 1 300 7 120 1 300

9 6 1 500 9 140 1 500

10 8 1 800 10 160 1 800

10 (Trf.) 8 1 800 10(Trf.) 180 1 800

11 8 1 800 11 160 1 800

12 200 2 000

13 200 2 200

NOTE — These are recommended pole sizes. If other sizes are used Distribution Technology shall be consulted.

f) Planting poles

1) Pole holes shall be dug in such a way that the longest side of the hole dug for the pole isparallel to the feeder line, the hole shall be dug so that the width is as narrow as possible whilstallowing the pole to be planted to the correct depth.

2) Base plates shall be installed for intermediate poles where there are poor soil conditions.

3) Base plates shall be installed for transformer and stayed poles in all soil conditions.

4) After a pole has been planted to the required depth, the soil that is to be filled into the hole shallbe slightly damp. If the soil is held in the hand and squeezed, it shall stay as it was squeezedafter opening the hand: that will indicate an optimum moisture content to ensure good soilcompaction.

g) Compaction

Compaction shall be in accordance with SCSSCAAO1.

h) Stays may be of the conventional type in accordance with D-DT-0165 or of the percussion type. Anexample using the “mule stay” is shown on D-DT-0350 sheet 2. Stay rod installation is shown onD-DT-0350 sheet 1.

4.11 Service connections

The service connections shall conform to the requirements of SCSASAAS3.

4.12 Customer installations

The customer installations shall conform to the requirements of SCSASAAS3.

4.13 Customer metering

The customer metering shall conform to the requirements of SCSASAAS3.


PAGE 30 OF 56

4.14 Drawings

Structure drawings for bare wire and ABC overhead reticulation systems and a list thereof, can befound in annex J.

A separate structure drawing for each reticulation method (single-phase, dual-phase, three-phase), forbare wire and ABC and for wood and concrete poles is provided.

NOTE — Bare wire lines are constructed on woodpoles only.

4.15 Bills of materials (BOM)

A bill of materials in list form is not provided, however all the materials required are described on eachdrawing and are referenced to SCSPVAAT6.

4.16 DT Project

A program called DT Project will be available from Distribution Technology, Simmerpan or the LocalOperating Divisions.

This tool will be used to provide a complete Bill of Resources for all structure types and conductorcombinations used on a particular project. It will interface with CAD systems and the Eskom ProjectManagement system (BMS) to provide the necessary Bills of Resources. (Refer to local operatingdivisions for clarification).

4.17 BMS codification

This is derived from DT project and does not form part of this standard except for the conceptualdescriptions given in annex H.

4.18 Marking and labelling

4.18.1 Statutory requirements

All controlling apparatus shall be permanently marked or labelled so as to identify the system or part ofthe system or the electrical machinery that it controls, and, where such control apparatus is accessiblefrom the front and back, these markings shall be on both the front and the back.

NOTE — Dymotape, masking tape, etc., are not a permanent labels and may not be used under any circumstances.The Local Operating Division labelling requirements are to be established and used for reticulation in that area.

4.18.2 Labelling requirements

All labels shall be permanently and indelibly inscribed and of a size that can be read from ground leveland shall be in accordance with ESKASAAN0.

4.18.2.1 Label colours

All labels shall have black letters on a yellow background.

4.18.2.2 Label sizes

The label size shall be in accordance with the labelling requirements. The material used shall bedurable and resistant to ultraviolet and pollution. Recommended materials are: Iscor Chromodek0,6 mm (Ref. PO4008 yellow) or aluminum alloy 25 painted with PVF2 yellow.


PAGE 31 OF 56

All lettering / numbering shall be a minimum of 50 mm high. It is recommended that Scotch vinyldecals (Ref. GSP220) be used.

4.18.2.3 Label position

The label shall be positioned in such a way that it is:

a) readable from ground level from the direction that is most logical from an operational perspective.

b) not accessible to the public.

4.18.2.4 Equipment to be labelled

at transformer:

a) each feeder

b) LV fuses or circuit-breakers

along the line:

pole-top boxes.

5 Tests and commissioning

To ensure the safe and reliable operation of a reticulation system the visual inspections and electricaltests shall be done before and after permanent energizing.

Sample inspection and test sheets are given in annexes F and G for use by the project resources. TheOHS ACT shall be the minimum requirement for testing and inspection.

5.1 Electrical tests

5.1.1 Insulation resistance tests

Disconnect the LV feeders at the transformer. With all pole-top box MCBs switched off use a 1 kVinsulation tester and test between each phase and earth as well as between phases. Care shall betaken to discharge the ABC before disconnecting the insulation tester leads. Record readings on a testresult sheet (annex H).

Expected results are 1 M� or higher between phases and 1 M� or higher between phase and neutral.If the results are below 1 M�, corrective action shall be taken.

5.1.2 Earth resistance tests

These tests shall be done in accordance with SCSASAAL9. These tests shall be done after theinsulation test.

Annex A(normative)


PAGE 32 OF 56

Conductor properties

Aerial Bundled Conductor (Refer SCSSCAAD5)

ACSR

AAAC


PAGE 33 OF 56

Conductor properties — LV ABC

1 2 3 4 5 6 7 8 9

ConductorThickness of dielectric

mm (Note 1)

Type of conductor of core Conductorsize mm 2

Number ofwires

Resistance at20 °C

� / km max.

Diameter ofconductor

mm

Breakingforce

N

Min Max Min Average Min Max

Phase(aluminum)

3570

719

0,8680,443

6,69,3

7,510,2

45008900

1,31,5

1,11,3

1,51,7

Supporting & neutral(aluminum alloy)

35

50

7

7

0,986

0,720

6,6

7,7

7,5

8,4

10300

14200

N/A

N/A

N/A

N/A

N/A

N/A

NOTE 1 — Columns 8 and 9 show the preferred radials as these are believed to be the most cost effective. Due to the manufacturing technology differences which may exist productswith up to the following radial thicknesses will not be rejected provided that they are within the concentricity requirements described below:

Table of maximum dielectric thicknesses and concentricity

Core (mm 2) Average (mm) Maximum (mm) Minimum (,,)

35 1,6 1,8 1,5

70 1,8 2,0 1,5


PAGE 34 OF 56

Conductor properties — ACSR & AAAC

1 2 3 4 5 6 7 8 9 10 11

Conductor Stranding Copper Mechanical properties Coeff. Electrical properties

Code

Name

and wire dia. Equiv.

Area

Overall

Dia.

Total

Area

Mass Breaking

Load

Final

Modulus

of linear

expansion

D.C. res.

@ 20° C

Rating

@ 75° C

mm mm2 mm mm2 kg/km kg GPa 10-6 / ° C �/km A

Table A1 - ACSR (Aluminium Conductor Steel Reinforced) - Extra Strong

Magpie 3/4/2,118 6,65 6,35 24,71 139,7 1893 133,76 13,68 2,707 78

Table A2 - ACSR (Aluminium Conductor Steel Reinforced

Squirrel 6/1/2,11 12,9 6,33 24,48 85,2 818 80,4 19,31 1,3677 110

Fox 6/1/2,79 22,58 8,37 42,8 149 1340 80,4 19,31 0,7822 155

Mink 6/1/3,66 38,71 10,98 73,65 257 2230 80,4 19,31 0,4546 215

Hare 6/1/4,72 64,52 14,16 122,48 427 3670 80,4 19,31 0,2733 290

Table A3 - AAAC (Aluminium Conductor Aluminium Alloy reinforced)

Acacia 7/2,08 13 6,24 23,79 65 682 61 23 1,39 110

35 7/2,77 22 8,31 42,18 115 1210 61 23 0,785 155

Pine 7/3,61 38 10,83 71,65 196 2060 61 23 0,462 215

Oak 7/4,65 63 13,95 118,9 325 3400 61 23 0,279 290

Table A4 - Galvanized Steel Wire

1/4 1/4,00 – 4 12,57 102 1410 193 11,52 14,67 27

3/3,35 3/3,35 – 7,35 26,44 215 2910 191 11,52 7,4 41


PAGE 35 OF 56

Annex B(normative)

Design spans for bare neutral ABC systems


PAGE 36 OF 56

Annex C(normative)

Design spans for ACSR bare wire systems


PAGE 37 OF 56

Annex D(normative)

Design spans for AAAC bare wire systems


PAGE 38 OF 56

Annex E(informative)

Urban reticulation

Typical mid block design


PAGE 39 OF 56

Annex F(normative)

Reticulation — Inspection sheet

ESKOM

PROJECT

QUALITY ASSURANCE

Page 1 of 4

ELECTRIFICATION - INSPECTION SHEET

PROJECT NAME : ______________________________DISTRICT : ________________________

PROJECT DESCRIPTION : _________________________________________________________________________

CONTRACTOR : ___________________________ REPRESENTATIVE : ___________________Company Name Print Name

CONSULTANT : ___________________________ REPRESENTATIVE : __________________Company Name Print Name

INSPECTION CRITERIA : INITIAL ACCEPTANCEDESCRIPTION Yes No Remarks Contractor EskomSite Store - Store facilities suitable

- Dead-ends/Guygripsstored indoors

- Storeman- Record of all material/

proper documentation- Received- Issued (Daily)- Storage/Stacking

- Poles- Conductor- Hardware- Wastage

- Materials damaged- Surplus materials- Material problems

(not to specification)Material - HandlingPeggingExcavations - Depth

- Hole orientation- Barricading

Poles planted - Planting depth- Pole planting equipment- Plumbness of poles- In line of poles- Pole orientation (Weak axis in

line)- Span length- Compaction - Tested


PAGE 40 OF 56

Annex F(continued)

ESKOM

PROJECT

QUALITY ASSURANCE

Page 2 of 4


INSPECTION CRITERIA : INITIAL ACCEPTANCEDESCRIPTION Yes No Remarks Contractor EskomStays/Flying Stays/Struts

- Excavations correct- Depth of excavations- Compaction tested- Stay insulator fitter- Stays in line- Stay depth- Stay angle (Bi-sector)- Thimbles fitted- Stay bracket orientation- Guy crimps locked- Kick plates + 400 mm wood

poles- Anti-climb devices- Stay guards- Planing depth of struts

Stringing - Stringing equipment checked- Running out of conductor- Sagging- Joints - midspan (full tension)

- jumpers (non tension)- Preforms locked

Clearances - MV- Transformer installations- Link installations- Strainer installations-- Stays/Struts- Trees (min. 3 m)- Road/Telkom crossings

(as per attached tables)- LV- Ground clearance (min. 3,3 m)- Structures (min. 2 m)- Road crossings (min. 4,7 m)- Tress (min. 1 m)

Earthing-MV - TRFR/Link structures(3 point star arrangement)

- Surge arresters earthed(jumpers-short/straight)

- MV/LV earths separated (5 m)- Earth readings (witness tests)


PAGE 41 OF 56

Annex F(continued)

ESKOM

PROJECT

QUALITY ASSURANCE

Page 3 of 4


INSPECTION CRITERIA : INITIAL ACCEPTANCEDESCRIPTION Yes No Remarks Contractor Eskom- LV

- All spurs earthed (1st pole away from transformerstructure - 5m separation)

- Bare neutral conductor bonded to earth ferruleon earthed poles

Pole-mounted boxes- Phase conductor - IPC connectors(black)- Neutral conductor - IPC connectors (blue)- Earth conductor - IPC connectors (blue) or- Neutral conductor - PG clamp- Earth conductor - PG clamp or- Neutral/Earth - one crimp connector for both- Bridge installed (neutral/earth bars in box)

NOTE - On structures carrying MV and LV, pole-mountedboxes must be mounted below bundle conductor.

Bundled conductor (ABC) connections- Phase-Phase IPC connectors (black)- Neutral-Neutral - 2 bolt PG clamp or

1 x crimp connectorTransformer installations

- Transformer mounted on broad face off pole- Danger label- LV box- Neutral SA installed- Phases connected- Line taps (check clearance)- Insulated lugs (check crimping/damage) to

insulation/correct lug for conductor)- Neutral conductor insulated from stain clamp to

bushing- Compression gland fitted- Clearances in box- Bundle conductor (each spur) entered into box

(no jumpers)- Open holes in box blanked off- Lock nuts used on LV bushings- No pole mounted boxes on Trfr struct.- Is the LV neutral fitted mechnically tight on the

transformer bushing?- Is the LV blue phase fitted mechanically tight on

the transformer bushing?- Is the LV red phase fitted mechanially tight on the

transformer bushing?- Is the LV white phase fitted mechanially tight on

the transformer bushing?


PAGE 42 OF 56

Annex F(continued)

ESKOM

PROJECT

QUALITY ASSURANCE

Page 4 of 4


INSPECTION DONE BY: ____________________________ ____________________________Print Name

____________________________ ____________________________Signature Date

CONTRACTOR: ____________________________ ____________________________Print Name

____________________________ ____________________________Signature Date

CONSULTANT: ____________________________ ____________________________Print Name

____________________________ ____________________________Signature Date


PAGE 43 OF 56

Annex F(continued)

ESKOM

PROJECT

QUALITY ASSURANCE

Page 1 of 2

SITE STORES - INSPECTION SHEET

PROJECT NAME : ______________________________DISTRICT : ________________________

PROJECT DESCRIPTION : _________________________________________________________________________

CONTRACTOR : ___________________________ REPRESENTATIVE : ___________________Company Name

CONSULTANT : ___________________________ REPRESENTATIVE : __________________Company Name Print Name

INSPECTION CRITERIA : (NB: Inspection to be done against attached specification) ACCEPTEDDESCRIPTION Yes NoSite Store

- Storage area demarcated with respect to material types- Mesh security fence 2,4 m high with rolled razor top wire- Gates positioned as per specification- Access controlled 24 h a day- Issue and receipt of material controlled by an appointed person- Risk items (i.e. copper) secured under lock and key including scrap copper- Smaller items (i.e. nuts, bolts, clamps, etc.) kept in stilages (steel mesh

baskets)- Standard incident reporting system maintained

Storage/HandlingMaterials packed and stored in a way- that it is easily assessible- that it is easily countable- to prohibit deterioration- to make handling safe and easy- that handling does not constitute a danger to other materialAll material stored within storage areaSecurity lighting to cover entire area

Material record keepingRecord keeping system- Computer as per specification (Electrification/major reticulation contracts)Material deliveries to site recordedMaterial issued for construction recorded


PAGE 44 OF 56

Annex F(continued)

ESKOM

PROJECT

QUALITY ASSURANCE

Page 2 of 2

Storeman

Name: _________________________________________

Skilled / Unskilled: _________________________________________

Computer literate: YES NO

INSPECTION DONE BY: ____________________________ ____________________________Print Name

____________________________ ____________________________Signature Date

CONTRACTOR/STOREMAN: _______________________ ____________________________Print Name

____________________________ ____________________________Signature Date


PAGE 45 OF 56

Annex F(continued)

Specification for site storage area and security

F.1 Electrification and major reticulation projects

F.1.1 Site store

The successful Contractor shall be responsible for ensuring that:

a) Storage area is suitably demarcated with respect to material types.

b) Mesh security fence is 2,4 m high with rolled razor wire fixed to top. Gates shall be positioned insuch a way that delivery vehicles can pass through without having to turn around.

c) Access is controlled 24 h a day.

d) Issued and receipt of material is controlled by an appointed person.

e) Risks items such as copper are secured preferably under lock and key. This includes copperscrap. Smaller items such as nuts, bolts, clamps, lugs, etc., shall be kept in stillages. (steel meshbaskets)

f) Loss of material is immediately reported to the Consulting Engineer / Local Eskom Security, ProjectManager or Project Co-ordinator / COW. The standard incident reporting system is maintained.

g) Material description, quantities and condition are all verified by Eskom Construction / Contractor inconjunction with Logistics before signing of picking tickets and leaving Eskom store.

h) Eskom approved under cover storage is available for items that can be damaged by rain.

Electricity shall be supplied by the contractor.

F.1.2 Storage practices

Materials shall always be packed and stored so that:

a) they are easily accessible;

b) they are easily countable at stock-taking times;

c) deterioration of the item is prevented;

d) handling is safe and easy;

e) handling of materials does not constitute a danger to other materials.

All material shall be stored within the storage area.

Security lighting shall cover the entire storage area.


PAGE 46 OF 56

Annex F(continued)

F.1.3 Materials supplied by Eskom for incorporating into the works by the contractor

A good record-keeping system that controls quantities on site shall be in place. All new deliveries tothe site-store and all materials issued for construction shall be recorded. It shall at any time bepossible for the Project Manager to establish from these records exactly what material is in the store orhas been erected. These figures will regularly be compared to the actual quantities measured on siteand the formal Eskom issuing invoices.

The contractor shall have a computer on site to use to facilitate accurate material stock control. Stockcontrol software and training can be obtained through the Employer. The contractor’s computer literatestoreman shall be available for training. The computer shall have a minimum:

Computer : 486 . DX2 - 50Hard drive : 1G byteRam : 16M byteStiffy Disk drive : 1,44M byte14” Colour screenDot Matrix Printer200 VA UPS220 V generator and UPS if no electricity is availableStock control software and Windows operating systemStock control system requirementsProgramme OtokonDatabasis SQLTraining 1 day courseComputer Contractor to provideStaff required per project1 x computer operator (Site Storeman)1 x Semi skilled labourer at Eskom stores to verify quantities

It will at all times be assumed that the contractor has ensured upon issue of material that there is novisible damage to it. In the case of damaged material, acceptance shall be refused. If a dispute arisesthe Project Co-ordinator shall be called in for a decision. Damaged material found on site will bereplaced at the contractor’s cost and no extension of contract time will be granted for any extra deliverytime.

Liability for inherent defects in Eskom-issued material shall not lie with the contractor and if defects inmaterial or in the works due to the use of latently defective material is discovered, new material will beissued free of charge and the contractor compensated for any additional expenses incurred due tothese defects, including delivery costs. If warranted, extension of contract time will also be granted.

A detailed programme of the works including an indication of when and in what quantities material willbe required, shall be provided by the contractor within two weeks of award of the tender. This list willform the basis on which material will be made available by Eskom, notwithstanding the fact that ageneral indication of the expected flow of material was provided. It shall be a requirement of thecontract that at least two weeks advance notice be given when any specific material will be required.Failure to give advance notice may lead to the late issue thereof in which case any resultant loss oftime will be the contractor’s responsibility and no extension of the contract period will be granted. Thisshall apply where material is ordered for which no requirement was stated in the programme of works.


PAGE 47 OF 56

Annex F(concluded)

Once the material has been issued, the off-loading and safekeeping thereof shall be the responsibilityof the contractor. He shall make the necessary arrangements for safe storage on site, offeringadequate protection against theft, damage, wind and weather. The responsibility for material againstany form of damage or theft after issue thereof shall also rest with the contractor. Procedure PEN70/005 Rev 0 “Decommissioning of Northern Engineering Division Capital Assets” in conjunction withACP 60 shall form the basis to be adhered to.

Excess project material shall be returned to stores within 14 days of project completion for minor itemsand immediately for major items. No material shall be left on site once the construction camp hasbeen relocated.

The contractor shall negotiate a fenced camp with the store manager, to collect material when itbecomes available. Preferably the contractor shall provide a container with lockable facilities and astoreman to keep record of material obtained and to verify the picking tickets. The storeman shall alsobe able to communicate with the office in order to arrange transport for material delivery to site.

F.2 House connection contracts

If agreed with the infrastructure contractor, the same storage area can be utilized. A separate storeshall be maintained by the house connection contractor.

F.2.1 Site store

A Kardex system shall be implemented on all Construction Site Stores for house connection materialcontrol.

The following information shall be reflected on the Kardex cards:

a) date of receipt and issuing of material;

b) document number (delivery note number, picking ticket, list number);

c) quantities received;

d) quantities issued; and

e) balance.

Once a month a full stock take shall be done by the storeman and any abnormalities reported to theSite Supervisor.

If not sharing the site store area with the infrastructure contractor, a suitable storage area that willinclude adequate under cover storage security and lighting shall be identified.

The store shall not carry material for more than 300 6700 connections at any time.

Delivery and verification of all materials issued, shall be the responsibility of the contractor.

Storage practices : as for electrification.

Return excess materials : as for electrification

All materials shall be stored in the storage area.

Annex G(informative)


PAGE 48 OF 56

Electrical test record sheet

Township reticulation scheme :_________________________________________________________

Date : ______________________ Testers name : ______________________________________

Address : ______________________________________

Tel. No.: ______________________________________

Transformer No.: ________________________

MV Voltage ________________________ kV.

G.1 LV ABC insulation resistance

R-W _________ MW at 1 kVW-B _________ MW at 1 kVB-R _________ MW at 1 kVR-N _________ MW at 1 kVW-N _________ MW at 1 kVB-N _________ MW at 1 kV

Instrument used _____________ Instrument No. _____________________

G.2 Earth resistance tests

In accordance with part 2 of the Distribution Standard.Attach test results.

G.3 Voltage level tests

G.3.1 No load voltage levels at terminal points on

Feeder 1 Feeder 2 Feeder 3

R-N______V R-W______V R-N______V R-W______V R-N______V R-W______VW-N______V W-B______V W-N______V W-B______V W-N______V W-B______VB-N______V B-R______V B-N______V B-R______V B-N______V B-R_______V

G.3.2 Voltage tests at houses

Is it within statutory limits?

G.3.3 Full load voltage levels at terminal points on :

Feeder 1 Feeder 2 Feeder 3

R-N______V R-W______V R-N______V R-W______V R-N______V R-W______VW-N______V W-B______V W-N______V W-B______V W-N______V W-B______VB-N______V B-R______V B-N______V B-R______V B-N______V B-R_______V


PAGE 49 OF 56

Annex H(informative)

BMS codification structure using the DT project tool


PAGE 50 OF 56

Annex J(normative)

List of drawings

The following drawings form part of this annex:

J.1 List of three-phase ABC wood pole drawingsNo. Description Rev

D-DT-1100 ABC Suspension Assembly 0-30 3

D-DT-1120 LABC Terminal Assembly 4

D-DT-1121 ABC Strain Assembly (0-60°) 5


D-DT-1140 ABC T from Intermediate 4

D-DT-1141 ABC Intermediate Suspension Assembly 4

D-DT-1142 ABC T from Strain 4

D-DT-1143 ABC X Intermediate-Strain Assembly 4

J.2 List of three-phase bare wire wood pole drawingsNo. Description Rev

D-DT-0920 Intermediate Assembly 4

D-DT-0921 In line strain Assembly 4

D-DT-0922 Angle Assembly 1-100° 4

D-DT-0924 Terminal Assembly 4

D-DT-0925 T-off from Intermediate 4

D-DT-0926 Intermediate-Intermediate Crossing 4

D-DT-0927 T-off from strain 4

D-DT-0928 Cable to BW connection 2

D-DT-0929 Service Box connection 4

D-DT-0932 ABC to BW connection 2

D-DT-0934 Intermediate-Strain Crossing 2

D-DT-0935 Strain-Strain Crossing 3

J.3 List of dual-phase ABC wood pole drawingsNo. Description Rev

D-DT-1145 ABC Suspension Assembly 0-30 0D-DT-1146 LABC Terminal Assembly 0D-DT-1147 ABC Strain Assembly (0-60°) 0D-DT-1148 ABC Strain Assembly (60-90°) 0D-DT-1149 ABC T from Intermediate 0D-DT-1150 ABC Intermediate Suspension Assembly 0D-DT-1151 ABC T from Strain 0D-DT-1152 ABC X Intermediate-Strain Assembly 0

Annex J(continued)


PAGE 51 OF 56

J.4 List of dual-phase bare wire wood pole drawingsNo. Description Rev













J.5 List of single-phase ABC wood pole drawingsNo. Description Rev


D-DT-1154 ABC Terminal Assembly 0








PAGE 52 OF 56

Annex J(continued)

J.6 List of single-phase bare wire wood pole drawingsNo. Description Rev













J.7 List of three-phase ABC concrete pole drawingsNo. Description Rev









J.8 List of single-phase ABC concrete pole drawingsNo. Description Rev










PAGE 53 OF 56

Annex J(continued)

J.9 List of dual-phase ABC concrete pole drawingsNo. Description Rev









J.10 List of auxiliary drawingsNo. Description Rev

D-DT-0165 Concrete pole LV stay Assembly 5

D-DT-0166 Stay attaching methods for concrete poles 3

D-DT-0167 Strut Pole for 7m and 9m concrete poles 2

D-DT-0168 Flying stay for concrete poles 2

D-DT-0180 ABC System Service Box Assembly 5

D-DT-0183 Bare wire Service Box Assembly 3

D-DT-0300 ABC full Tension compression Joint 3

D-DT-0302 ABC Full Tension compression Joint - Joining a core 1

D-DT-0305 BN ABC Intermediate Suspension with S/Box - Assembly Detail 6

D-DT-0307 BN ABC -Intermediate Suspension without S/Box - Assembly Detail 2

D-DT-0309 SABS 780 Transformer and LV Fuseholder connections Sheet 1 0




D-DT-0314 LV Barewire Connection Methods 0

D-DT-0315 Stay Assembly details 0

D-DT-0330 Pole Foundation Arrangement 2

D-DT-0332 Pole Planting Depths-Wood and Concrete 2

D-DT-0335 MV and LV Pole Hole Legend 0

D-DT-0336 Woodpole Hole positions

D-DT-0339 Concrete pole orientation layout 0

D-DT-0340 Surge Arrester connections 2

D-DT-0345 Schematic for 160kVA CSP Pole mounted transformer 1

D-DT-0348 Example for Shared Structure Clearances-MV, ABC and Telkom 3

Annex J(continued)

../../../ftp.eskom.co.za/pub/distribu/docs/dsprt03/0330r3c.pdf


PAGE 54 OF 56

No. Description Rev

D-DT-0349 Example for shared structure clearances ABC and Telkom 2

D-DT-0350Sheet 1

Stay rod installation detail 2

D-DT-0350Sheet 2

Mule stay Rod installation Detail 2

D-DT-0354 Streetlight Assembly 4

D-DT-0356 LV Surge Arrester Installations 2

D-DT-0357 Rock Anchor Installation 2

D-DT-0363 Fourway Pole top box connection detail - Sheet 1 2

D-DT-0363 Fourway Pole top box connection detail - Sheet 2 2

D-DT-0364 Terminal assembly for meter box customer from ABC 2

D-DT-0365 Service connection from Con. Intermediate pole

D-DT-0980 MV / LV Bare Wire Staying Methodology 0

D-DT-0981 LV Metering Unit - Sheet 1 0




D-DT-0982 Eye Nut Assembly 0

D-DT-0983 LV Barewire Binding Techniques 0

D-DT-1165 LV Stay Assembly for Woodpoles

D-DT-1167 Strut for 7m and 9m Woodpoles 3

D-DT-1168 Flying Stay Arrangement for Wood Poles 3


PAGE 55 OF 56

Annex K(informative)

Bibliography

The following documents, in addition to those in clause 2, were a source of reference in compiling thisstandard. They do not constitute provisions of this standard but are referenced for further information.

NRS 018, Fittings and connectors for LV overhead powerlines using ABC cable.

NRS 018-1:1995, Fittings and connectors for LV overhead powerlines using ABC cable — Part 1:Strain and suspension fittings for self-supporting ABC.

NRS 018-2:1995, Fittings and connectors for LV overhead powerlines using ABC cable — Part 2:Strain and suspension fittings for insulated supporting core ABC.

NRS 018-4:1995, Fittings and connectors for LV overhead powerlines using ABC cable — Part 4:Strain fittings for service cables. (No draft available).

NRS 027:1994, Distribution transformer — Completely self-protecting type.

NRS 034-1:1992, Guidelines for the provision of electrical distribution networks in residential areas —Part 1: Planning and design of distribution systems : with amendment 1, Financial analysis.


PAGE 56 OF 56

Annex L(informative)

Revision information

DATE REV.NO. NOTES

0 Not issued

June ‘95 1 Original issue

February ‘96 2 A general improvement to the clarity, content andlayout of rev.1. The minimum ground clearance of2,5 m for service connections, stipulated in rev.1,has been reduced to 2,2 m in rev.2.

April ‘97 3 References to service connections standard Part 8section 1 added

July ‘97 4 Expanded to include single-phase and dual-phaseand generally modified for clarity

Documents

Distribution Standard