SECTION 1 STANDARD TECHNICAL SPECIFICATION Power specifications.pdf · SECTION 1 STANDARD TECHNICAL...

Millennium Challenge Account Namibia: Design, Environmental Assessment and Supervision of Construction of Quarantine Camps

Consulting Services Africa

SECTION 1

STANDARD TECHNICAL

SPECIFICATION

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1 STANDARD TECHNICAL SPECIFICATION

1.1 NORED STANDARD SPECIFICATION All equipment supplied, work executed and procedures employed in terms of this contract shall comply fully with the latest revision of the NORED Standard Specification, which is NOT included in this document, but which is available on application from :

The Chief Executive Officer NORED Electricity PO Box 3544 ONGWEDIVA Tel : +264 065 280800 Fax : + 264 065 280848 Email : [email protected]

1.2 SUITABILITY , INTERCHANGEABILITY AND STANDARDISATION OF EQUIPMENT All equipment supplied and installed under this contract shall be suitable, and designed, for its intended application. In particular, all conductor and / or staywire clamps and dead-ends or conductor termination lugs or jointing ferrules shall be specifically designed, sized and suitable for the task and function to be performed. Contractors shall submit schedules listing all clamps, dead-ends, connectors and lugs to be used on each type and size of conductor, cable or staywire for approval prior to commencement of construction. The size, type number and / or colour coded identification tag of each component shall be provided and cross-referenced to the conductor, cable or staywire on this schedule.

Similar equipment, designed to perform identical functions under similar conditions to be supplied under this contract must be identical in all respects and it shall be possible to exchange any item with any other similar item without affecting the operational integrity of the works.

All auxiliary equipment must also be identical, including items such as contactors, fuses, motors, fans, method of wiring, numbering of wires, relays, indication lamps, instruments and other parts.

Similar items of equipment, for example such items as fuses, fuse holders, switches, contactors, circuit breakers, lamp holders, push buttons, etc., shall, where possible, be of the same manufacture.

Items of similar appearance, whose application cannot be readily identified through visual inspection, shall be clearly marked with a unique and indelible code or number, which shall then be also reflected on the appropriate drawings.

1.3 STANDARD SPECIFICATIONS All electrical installation work shall comply with SANS 10142, and distribution and reticulation systems, overhead and/or underground, shall in general comply with all the conditions of the Code of Practice for Overhead Power Lines for Conditions Prevailing in South Africa, the Machinery and Occupational Safety Act, the Post Office Act as well as all requirements issued by Nampost, Nampower and other statutory bodies involved, where applicable.

All the equipment and materials shall conform to the relevant SANS / SABS, NRS, BSS or IEC Specifications and the latest revisions thereof, where applicable.

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DESCRIPTION OF SPECIFICATION SOUTH AFRICAN STD IEC BSS

1. SWITCHGEAR, DISTRIBUTION AND CIRCUIT BREAKERS

1.1 Circuit breakers above 1 kV SANS 62271 62271 5311

1.2 Circuit breakers below 1 kV SANS 556

1.3 HV Switches SANS 60265

1.4 Electrical power, switchgear and associated equipment

SANS 60947 5227/5486

1.5 Metal-clad switchgear NRS 003 SANS 1885 5227

1.6 Metal-enclosed ring main units – 1kV to 24kV

SANS 1874

1.7 Insulation co-ordination 71

1.8 Bushing for alternating voltage above 1kV

SANS 60137 60137

1.9 Busbars and busbar connections SANS 1195 159

1.10 Insulated bushings SANS 60137 60137 223

1.11 Transformer bushings SANS 1037 SANS 1371

1037

1.12 Specification and acceptance on sulphur hexa fluoride (SF6)

1.13 Low voltage surge diverters SANS 61643

1.14 Distribution gapless metal-oxide surge arresters

NRS 039 SANS 60099 99-1

1.15 Current transformers NRS 029 SANS 60044 60044 3938

1.16 Voltage transformers NRS 030 SANS 60186 60186 3938

1.17 Capacitors 70 1650

1.18 Cable sealing boxes 2562

1.19 Moulded case circuit breakers SANS 156

1.20 Flameproof enclosures for electrical apparatus

SANS 60079 60079

1.21 Isolators and earthing switches NRS 031 129 5253

1.22 Recommendations for the classification of materials for the insulation of electrical machinery and apparatus in relation to in service thermal stability

85

1.23 Electrical terminals and connections SANS 1433

1.24 Meter cabinets & meter / distribution kiosks

NRS 056 SANS 908

1.25 Stationary lead-acid batteries SANS 60896 60896

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1.26 Industrial battery chargers SANS 1652

1.27 Pole-mounted reclosers and sectionalisers NRS 036

1.28 Portable earthing gear for busbar systems and overhead lines

SANS 1934

1.29 Earth leakage relays SANS 767

1.30 Flush mounted distribution boards SANS 1765

1.31 Switches for household and fixed installations

SANS 6069

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2. TRANSFORMERS AND MINISUBS

2.1 Power transformers SANS 60076 60076 171

2.2 Distribution transformers SANS 780 76

2.3 Minisubstations SANS 1029

2.4 Insulating oil for transformers and switchgear

SANS 555 296 148

3. CABLES

3.1 3,3kV up to 33kV paper insulated cables SANS 97

3.2 Electric cables up to 3,3 kV SANS 1507

3.3 Low voltage electrical cords SANS 1574

3.4 XLPE insulated cables up to 33kV SANS 1339

3.5 Welding cables SANS 1576 638.4

3.6 The selection, cabling and installation of electric power cables

SANS 10198

3.7 Cable terminations and live conductors within air-insulated enclosures (insulation co-ordination up to & including 36kV)

NRS 012

3.8 Pilot cables NRS 011

3.9 MV cables NRS 013

3.10 Concentric house service cable NRS 063

3.11 Cable lugs and ferrules NRS 028

3.12 Mechanical cable glands SANS 1213

3.13 Glands for PVC-insulated cables SANS 808

4. AERIAL BUNDLED CONDUCTORS

4.1 Aerial bundled conductor cable systems SANS 1418

4.2 Installation of ABC cables SANS 10198

4.3 LV aerial bundled conductors – fittings & connectors

NRS 018

4.4 Cable ties for use with aerial bundled conductors

NRS 020

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5. LIGHTING

5.1 Streetlighting SANS 10098

5.2 Photo electric control units (PECU’s - daylight switches) for lighting

SANS 1777

5.3 Ballasts for tubular fluorescent luminaires

SANS 890, SANS 891

5.4 Tubular fluorescent lamps SANS 1041

5.5 Interior luminaires for fluorescent lamps SANS 1119

5.6 Capacitors for tubular lamp fluorescent luminaires

SANS 1250

5.7 Ballasts for tubular fluorescent lamps SANS60921

5.8 Electronic ballasts for tubular fluorescent lamps

SANS60929

5.9 Design & construction of lighting masts SANS 10225

5.10 IP codes SANS 60529

6. INSTRUMENTS AND RELAYS

6.1 Electrical instruments and meters 51 5685/89

6.2 Electrical protective relays 142

6.3 Indicating instruments 89

7. MOTORS

7.1 Induction motors SANS 1804 5000

7.2 Small motor starters & contactors SANS 60947 587

7.3 General requirements for rotating electrical machines

SANS 60034 60034 4999

7.4 Specification for electrical overhead travelling cranes

SANS 4301 466

7.5 Dimensions of electric meters 3974

7.6 Specifications for grey iron castings 1452

8. FUSES

8.1 LV fuses up to 1 000V SANS 60269 88

8.2 HRC fuses SANS 60269 2692

8.3 Outdoor distribution fuse cut-outs (drop-out fuses) up to 33 kV

NRS 035

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9. CREDIT & PRE-PAYMENT METERS

9.1 Electricity payment systems, Part 1 : Prepayment meters

SANS 1524

9.2 Electricity sales systems NRS 009

9.3 kWh meters NRS 057 SANS 61358 SANS 62053

61358 37

10 WIRING

10.1 Code of Practice for the Earthing of Low Voltage Distribution systems

SANS 10292

10.2 The wiring of premises SANS 10142

11. OVERHEAD LINES

11.1 Code of practice for overhead lines SANS 10280

11.2 Copper conductors SANS 182-1

11.3 Aluminium alloy conductors SANS 182-2 3242

11.4 Aluminium conductors, steel reinforced, for overhead power transmission lines

SANS 182-3 215

11.5 Zinc coated steel wire SANS 182-5

11.6 Pine poles and cross-arms SANS 753

11.7 Eucalyptus poles and cross-arms SANS 754

11.8 Post insulators SANS 60720 60720

11.9 HV line post insulators SANS 60383 137

11.10 Insulator and conductor fittings SANS 61284 3288

11.11 Manual No 52 (1971) : Guide for the design of steel transmission lines

ASCE

11.12 General purpose galvanised steel wire 183

11.13 Stays and associated components NRS 022

11.14 Service distribution box (CDU) – Single-phase outdoor pole-mounted

NRS 032

11.15 Pole-mounted auto-reclosers & sectionalisers less than 33 kV

SANS 036

11.16 Composite insulators SANS 61109

12. LOW COST RETICULATION

12.1 Distribution board for use in low cost urban reticulation development (“Ready Board”)

SANS 1619

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12.2 Guidelines for the provision of electrical distribution networks

NRS 034

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13. CIVIL WORKS-EXCAVATIONS

13.1 Standardised specification for civil engineering construction:

(1) Site clearance SANS 1200C

(2) Earthworks (small work) SANS 1200DA

(3) Earthworks (Pipe trenches) SANS 1200DB

(4) Bedding (Pipes) SANS 1200LB

(5) Cable ducts 1200LC

14. STEELWORK AND TREATMENT

14.1 Structural steel sections SANS 1200 H

4

14.2 Weldable structural steels SANS 1431 4360

14.3 Fasteners SANS 1700

14.4 Code of practice for the structural use of steelwork

SANS 10162

14.6 Structural steel SANS 1431

14.7 Structural steel tables SAISC

14.8 Mild steel rivets SANS 1700

14.9 Electro-plated coatings SANS 1700 1872

14.10 Hot-dip galvanised coatings on iron and steel

SANS 121 SANS 32

14.11 Phosphate treatment of iron and steel 3189

14.12 Preparation of steel surfaces for coating SANS 10064

14.13 Protection of steel against corrosion SANS 14713

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15. PAINTING

15.1 Painting SANS 630

15.2 Undercoat painting SANS 681

15.3 Zinc chromate primers for steel SANS 679

15.4 National colour standard SANS 1091 3810

15.5 Calcium plumbate primer SANS 912

15.6 Metal etch primer SANS 723

16. RECORD DRAWINGS

16.1 Graphical symbols for electrical diagrams

NRS 002

16.2 International metric system M 33 A 3979

17. GENERAL

17.1 Glass-fibre products SANS 141

17.2 Quality of supply NRS 048 SANS 1816

17.3 Design and installation of earth electrodes

SANS 10199

17.4 Earth rods and couplers SANS 10064

17.5 Protection of structures against lightning SANS 10313

All other equipment and materials shall conform to the relevant NRS, SANS, SABS, BS or IEC specification, where applicable.

Where materials are covered by both SANS/SABS and BS or IEC specifications, the NRS, SANS/SABS specification shall be complied with unless otherwise specified.

1.4 MV METERING UNIT

1.4.1 SCOPE This specification covers the manufacture, supply, delivery, erection on site, testing and commissioning of three phase MV metering units for distribution systems.

1.4.2 GENERAL Pole-mounted MV metering units (MU’s) components shall comply in all respects with NRS 029 and SANS 60044 (CT’s) and NRS 030 and SANS 60186 (VT’s), and shall use oil as insulating medium.

Sufficient oil to SANS 555, in separate containers to enable the unit to be filled to the service level, shall be supplied with the unit. Suitable monitoring devices shall provide ample warning of low oil levels.

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MU covers shall be lockable to prevent unauthorised access.

Lifting and slinging facilities shall be provided for each MU.

All units shall be provided complete with bushings, CT’s, VT’s enclosures for kVA/kWh meters, control fuses, first filling of oil, earthing and test facilities.

1.4.3 PHASE CONFIGURATION Metering units shall be configured as three phase, four wire units, comprising three CT’s and three VT’s.

The VT star point shall be accessible in the terminal box through a 5 kV bushing for testing purposes, and shall be earthed to the MU tank by a removable link.

1.4.4 MU CONSTRUCTION

1.4.4.1 Enclosure The MU assembly shall be housed within an integral, air insulated, stainless steel enclosure. All hardware shall be made of stainless steel or brass for maximum corrosion-resistance. The enclosure shall be painted using a UV/corrosion-resistant epoxy paint. The enclosure shall be provided with lifting provisions. Earthing studs shall be provided for system earthing.

1.4.4.2 Combination Current/Voltage Transformers Commonly referred to as Metering Units, Combination Current/Voltage Transformers shall maintain the same electrical, accuracy and mechanical characteristics as individual CTs and VTs. Otherwise, physical dimensions may vary, depending on design.

1.4.4.3 CT’s Current Transformer windings (Typical configurations):

a) A single primary winding and single secondary winding with dual ratio tap.

b) A dual primary winding and a single ratio tap .

c) A single primary winding and one or more secondary windings with dual ratio tap(s).

d) Other combinations as available and approved by ISO.

e) Winding material shall be pure copper wires with cross-sectional area suitable to the current requirement.

Rated primary current : as per the Project Technical Specification

Rated secondary current : 5 ampere @ rated primary current

Accuracy class 0,5

Burden : 7,5 VA

Short time current withstand : 18 kA

1.4.4.4 Voltage Transformers Transformer windings shall consist of a single primary copper winding and one or more tapped secondary windings per phase.

Rated primary voltage : as per the Project Technical Specification

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Rated secondary voltage : 110 Volts (typical)

Secondary voltage : 110 V (line)

Voltage factor : 1,2 continuous and 1,9 for 30 seconds

Accuracy class : 0,2

Burden : 50 VA

Impulse withstand :

11 kV : 95 kV

22 kV : 150 kV

330kV : 200 kV

1.4.4.5 Terminal Box A terminal box shall be provided for termination of all MU windings, using M6 brass studs on insulated bushings.

The voltage transformer shall be provided with 10 A fuses in the terminal box.

A conductive gland plate shall be provided for multi-core metering cable entry.

1.4.4.6 Grounding The neutral terminal of the voltage transformer shall exit the tank via a 5kV insulated bushing and grounded by means of a removable copper strap to a NEMA 2-hole pad in the terminal box.

1.4.4.7 Primary Terminals The primary terminals shall be tin-plated NEMA 4-hole pads(4”x4”).

1.4.5 SPECIFIC REQUIREMENTS FOR GROUND-MOUNTED UNITS

1.4.5.1 General Enclosures shall be made of 2,7 mm (12 gauge) thick mild steel and manufactured to ANSI C37.72 and C57.12.28 standards. The enclosure shall be mounted independently to facilitate cable installation, if desired or for future replacement. The enclosure shall be provided with lifting provisions and painted with a UV-resistant paint.

1.4.5.2 Cable Termination Enclosure Requirements The cable termination enclosures shall be air-filled and shall be positioned on the side of the CT-VT unit with the following specific requirements.

1.4.5.3 Clearances a) For 11kV units, the enclosure shall be designed for the termination of three-core

XLPE or oil impregnated paper insulated cable (up to 95mm2

) by means of unscreened separable connectors.

b) For 22kV units, the enclosure shall be designed for the termination of three-core XLPE cable (up to 95mm

2

) by means of screened separable connectors.

c) The cable termination enclosure shall provide a minimum clearance of 50 mm from the back of the separable connector to the cable enclosure cover (see figure E.1 of annex E).

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1.4.5.4 Height of enclosure The minimum distance between the centre line of the bushings and the gland plate of an enclosure shall be as specified below.

Clearance (mm) Voltage rating of enclosure (kV) Cable size

12 24 36

up to 95 mm2 600 700 800

up to 185 mm2 650 750 900

1.4.5.5 Bushings a) The bushings shall comply with EN 50180 Type C (630A – tapered) bolted-type

bushings with a M16x2 thread. These bushings have an internal screen that shall be earthed.

b) The bushings shall be horizontally positioned. The phase sequence of all bushings shall be marked.

c) The bushing-centre spacing shall be ≥ 135 mm and the distance between the outer bushing-centres and the metal enclosure shall be not less than 90 mm.

1.4.5.6 Gland Plates and Cable glands a) A removable gland plate shall be provided for each cable termination enclosure.

The gland plate shall be designed in such a way that, once removed, the entire bottom of the cable box is open (i.e. the bottom of the cable box shall form the gland plate). The gland plate shall have a pre-drilled/punched cable entry hole of 110 mm diameter that is positioned below the attachment point of the centre phase bushing. The hole shall be fitted with a rubber grommet to seal the cable entry into the MV cable box.

b) A cable support clamp shall be provided below the cable termination enclosure for supporting the MV cable. This clamp shall be suitable for a cable with outer diameter in the range of 50 - 75 mm. The centre of the clamp (ie when a cable of diameter 75 mm is installed) shall be positioned to correspond with the centre of the cable entry hole in the gland plate.

1.4.5.7 Earthing for Cable Termination Enclosures a) An earth terminal shall be provided for earthing the MV cable within the enclosure.

b) The earth terminal shall be a 30 mm long boss, with an M12 thread throughout, welded to the enclosure at a height of 100 mm from the gland plate. The boss shall be fitted with a M12 × 25 mm setscrew, washer and spring washer. The boss and the setscrew shall be stainless steel.

1.4.5.8 Terminal Box The terminal box cover shall be provided with a sealing gasket.

A vertical support bracket shall be provided and positioned below the gland plate of the terminal box for support of the multi-core metering cable. The bracket shall be attached to the MU tank/frame and be vertically aligned with knock-outs provided in the gland plate of the terminal box.

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1.4.5.9 Plinth requirements A suitable plinth, suited to the MU pedestal, shall be used for all ground-mounted (free standing) MU’s. The pedestal base shall be provided with 4 x 18 mm diameter slotted mounting holes to clear the mounting bolts.

1.4.5.10 Marking and Labelling The source and load cable termination enclosures and covers shall be externally labelled ‘P1’ and ‘P2’ respectively. The labels shall be white and in characters larger than 50mm high.

An MV warning sign shall be fitted to the cover/lid of the cable termination enclosure. Pop-rivets fastening of labels is not acceptable.

All bushings and secondary terminals shall be labelled in accordance with the MU rating and diagram plate.

1.4.6 SPECIFIC REQUIREMENTS FOR POLE-MOUNTED UNITS

1.4.6.1 General Enclosures shall be made of 2,7 mm (12 gauge) thick mild steel and manufactured to ANSI C37.72 and C57.12.28 standards. The enclosure shall be mounted independently to facilitate cable installation, if desired or for future replacement. The enclosure shall be provided with lifting provisions and painted with a UV-resistant paint.

A galvanized, mild steel pole mounting bracket, permitting arrester mounting on both the load and line side bushings shall be provided.

1.4.6.2 Bushings Bushings shall comply with the requirements of clause 4.9 of SANS 780,

The bushing profile characteristics shall comply with annex D of SANS 60815.

The minimum creepage distance of the bushings shall be at least 20 mm/kV for inland and 31 mm/kV for coastal applications. For SWER applications, the nominal voltage used for the calculation of creepage distance is 33 kV.

The bushing stem shall be threaded and made from 12 mm copper.

The phase sequence of all bushings shall be marked on the MU housing.

All bushings shall be side wall mounted. Lid mounted bushings are not acceptable. All bushings rated at 11 kV and higher shall be clamped at the base of the bushing. The bushing design drawings must include the wall thickness the bushing is suitable for and tested on.

1.4.6.3 Pole-mounting Requirements a) Three-phase/dual-phase metering units

Three-phase/dual-phase CT-VT metering unit shall be mounted on an H-pole structure with a single galvanised steel platform..

b) SWER metering units

SWER metering unit shall be mounted on a single pole.

1.4.7 FACTORY PRODUCTION TESTS Each individual metering unit shall undergo a series of mechanical operations verifying correct functioning. The MU shall be AC hi-pot tested one minute phase-to-phase, phase-to-ground and across the open contacts. Circuit resistance shall be checked on all ways.

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1.4.8 REQUIRED INFORMATION The following drawings and information shall be provided :

a) 3 sets of drawings showing physical dimensions including mounting holes and primary CT terminal details, nameplate and schematic of connections shall be provided prior to ordering.

b) Copy of Quality Control /Quality Assurance (QC/QA) Manual applicable to production and testing of CT’s, VT’s and complete MU.

1.4.9 STANDARD COMPONENTS The following shall be included as standard:

a) Stainless steel metering unit enclosure painted with a corrosion-resistant epoxy paint with ultra-violet protection.

b) Metering cubicle/cabinet enclosure painted with a corrosion-resistant epoxy paint with ultra-violet protection.

c) kVA / kWh meter and metering multi-core cabling to CT/VT enclosure.

d) Stainless steel and brass fasteners.

e) Lifting provisions.

f) Grounding provisions.

g) Corrosion-resistant three line diagram and nameplate(s).

h) Surge arrester mounting provisions.

i) Surge diverters on each phase , upstream and downstream to the MU.

1.4.10 PAINTING Surface preparation and painting of the units shall comply with the requirements of SANS 10064.

Powder coat paint shall be used on all units. After curing, the paint shall have a minimum thickness of 0,1 mm, with an impact resistance of 5,65 J and a scratch resistance of at least 1 kg. Tenderers shall provide a statement of compliance with these requirements from the manufacturers with their offers.

1.4.11 LABELLING Labels, describing the MU components and tappings shall be screwed, not glued, to the unit housing.

The MU shall be provided with an engraved stainless steel rating plate which shall clearly identify :

a) Manufacturer and model

b) Serial number of the unit

c) Year of manufacture

d) All rated current and voltage values

1.5 RECORD DRAWINGS The Contractor shall submit full record as-built drawings.

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1.6 TESTING All cables, relays, switches, circuit breakers, transformers, streetlights, etc shall be tested for insulation to earth and for insulation between phases and between phases and neutral, where feasible.

On completion of all tests a test report shall be handed to the Engineer, stating the insulation resistance readings of the following:-

a) Between individual cores of all cables;

b) Between all cable cores and earth;

c) Between all normal live parts of switchgear and earth, as well as between phases of normally live equipment;

d) Between screening or armouring and earth of high voltage cables.



SECTION 2

PROJECT TECHNICAL

SPECIFICATION



2 PROJECT TECHNICAL SPECIFICATION

2.1 SCOPE OF WORK

2.1.1 GENERAL The new 33 kV over-head power line to be built, is to provide electricity to the Kopano Staff housing area. Staff houses are fully wired and supplied from a nearby generator. This project includes the connection of the transformer via underground cable to the existing changeover board in the generator room. The changeover board is to be upgraded to accompany the incomer from the transformer, and allow for switching between mains from NORED and the local generator should the generator be renovated in the future.

2.1.2 CONTRACTOR’S EXPERIENCE AND QUALIFICATIONS The work called for in this document requires electrical contractors to be suitably experienced and qualified and registered / licensed with NORED to do LV, 11 kV, 22 kV and 33 kV reticulation installation work. Proof of approval and registration with NORED is to be provided with all offers.

2.1.3 33 KV OVERHEAD POWERLINE AND TRANSFORMER A tee-off point is to be provided on an existing 33 kV line, and a new overhead powerline constructed to terminate near the staff housing area of Kopano Quarantine Camp. A 25 kVA, 33 000 / 415 V pole-mounted substation with metering facilities shall be provided at the line termination point and connected to the existing changeover panel in the generator room to provide power to consumers in the area.

2.2 SUPPLY AUTHORITY The Supply Authority is NORED, a Namibian Regional Electricity Distributor Company. All correspondence with the Supply Authority shall be routed via the Engineer.

All work related to the connection of new infrastructure to the existing powerlines shall be co-ordinated with NORED. No connection to existing reticulation shall be done without a permit to work issued by NORED, nor in the absence of NORED staff.

All construction work shall be inspected and approved by NORED and NamPower prior to tie-in to the existing network.

2.2.1 ELECTRICAL SUPPLY The main supply shall be taken from existing MV overhead powerlines in the vicinity (see site drawings) and connected to the new 33 kV overhead lines to be constructed under this contract. The new MV OHL will then provide power to the various consumers via suitable pole-mounted substations.

2.3 THE SITE

2.3.1 LOCATION The site is located in Kavango Region, located as follows :

NAME CO-ORDINATES (WGS 84)

1 Kopano Quarantine Camp S17.64067 E24.05667



2.3.2 SITE SURVEY , SETTING OUT AND BUSH CLEARING Prior to commencement of construction, overhead line routes have to be properly surveyed by professional registered land surveyors and set out to ensure that all obstacles are adequately cleared and that no potential hazards exist along the route.

After survey of the route (by a registered and professional land surveyor), setting out the line turning points shall commence, followed by bush clearing, 10,0 m wide, of the route. Pegging of the intermediate structures and stay positions shall be done only after bush clearing has been inspected and approved. After bush clearing has been completed, all tree and bush stumps and roots shall be completely removed from the soil and all resulting debris shall be removed from the cleared line route.

Fruit-bearing trees shall be avoided wherever possible in the process of line route selection, setting out and bush clearing. Where this is absolutely unavoidable, the contractor shall negotiate with the landowner in question and pay him/her a reasonable sum as compensation – the Engineer shall in any case be informed of each fruit-bearing tree affected and the contractor shall furnish him with a receipt, signed by the landowner, as proof of payment of such compensation for each affected tree.

Comprehensive spanning sheets on the prescribed format shall be prepared, indicating the relative positions of all pole structures and conductor span lengths, with the co-ordinates of all angle, tee-off and transformer structures indicated in latitude / longitude decimal degrees to the WGS 84 datum.

2.3.3 SITE CONDITION AT COMPLETION OF CONTRACT The Contractor shall ensure that the site is left in a neat and clean condition at the end of the Contract. He shall remove all equipment and material not used in, or left over from, the execution of the contract, as well as all rubble, off-cuts and other foreign material. Dumping shall occur only on authorised sites.

2.3.4 ELECTRICAL PARAMETERS

2.3.4.1 MV System (a) Nominal Voltage 33 kV

(b) Highest continuous voltage 36 kV

(c) System BIL 200 kV

(d) Phase Rotation R-W-B

(e) Fault level : 3 phase ± 1 000 A

1 phase ± 1 200 A

2.3.5 SITE FACILITIES The successful Tenderer shall provide, where applicable :

a) Sanitation for his own use.

b) Water for his own use. Potable water main supply is not necessarily available in the vicinity of the sites.

c) Board and accommodation for his staff and labourers.

d) Office, storage and security facilities on a suitable construction site, to be indicated during the site visit. All relevant documentation and drawings shall be permanently located in the site office.

e) Telephone facilities.



f) Site security and access control measures to ensure that theft of equipment is eliminated.

2.3.6 SITE INSPECTION Tenderers are encouraged to visit the sites during the tendering period, although attendance of a site inspection is not compulsory. During the inspection, tenderers shall thoroughly acquaint themselves with all prevailing conditions, and take these into consideration in preparation of offers. No additional claims arising from site access problems, soil conditions, transport difficulties, off-loading, handling, storage, labour, accommodation or housing will be considered, irrespective of whether the any tenderer has attended the site inspection in person or has sent a representative for this purpose.

Not visiting the site will be entirely at the tenderer’s risk. Tenderers will be deemed to have visited the sites irrespective of whether they physically did so or not.

2.4 TRANSFORMERS

2.4.1 GENERAL Transformers shall comply with the General Specification and SANS 780 in all respects.

2.4.1.1 Specific Requirements for Transformer ITEM REQUIREMENT

No-load voltage ratio on nominal tap 33 000 / 415 V

Nominal continuous rating 25 kVA, as per BoQ, at ambient temperature 40°C peak and 30°C average

Frequency 50 Hz

Number of phases 3

Vector group Dyn 11

Mounting Pole-mounted on approved galvanised steel cradles and cross-arms supported by wooden poles

Windings Double-wound, copper conductors

Tapping ratios Off-load tap selection, 0%, ±2,5%, ±5%

Oil The transformers shall be supplied with the first filling of oil to SANS 555

Cooling ONAN (Oil natural, air natural)

Paint finish “NOSA” Orange (SANS code B26, Light Orange)

2.4.2 TRANSFORMER EARTHING Separate MV and LV earth mats shall be provided as per standard NamPower requirements and drawings, and shall generally be as follows :

2.4.2.1 Pole-mounted Transformer MV Earth System The MV earth mat shall be a crow’s foot earth electrode, consisting of two 5 000 mm lengths of bare 50 x 3 mm flat copper bar, installed 1 000 mm deep, 2 000 mm away from the pole support.



At each end of the electrode, a 1 500 mm copper-coated steel earth rod shall be driven vertically into the ground from the bottom of the earth trench and connected to the electrode arms by means of special connection clamps.

The transformer tank earthing stud shall be connected to the MV crow’s foot earth electrode with insulated copper earth lead (size dependent on short circuit ratings, but 70 mm² minimum).

2.4.2.2 Pole-mounted Transformer LV Earth System The LV earth electrode shall be installed as per the relevant standard drawing, and shall consist of two 5 000 mm lengths of 50 x 3 mm flat copper bar in crow’s foot configuration, buried at least 1 000 mm below natural ground level. Each end of the electrode shall be provided with a 1 500 mm long copper-coated steel earthing rod driven vertically into the ground from the bottom of the earth trench and solidly connected to the copper bar by special connection clamps.

The transformer neutral bushing shall be connected directly to the centre of the LV crow’s foot earth electrode with 70 mm² insulated copper earth lead. Distribution kiosk / board earth bars shall be connected to the transformer neutral bushing only.

2.5 MV OVERHEAD POWER L INES

2.5.1 GENERAL The line shall be a 33 kV, three phase, overhead powerline, utilising wooden poles, line post insulators, and a single aluminium conductor, steel reinforced (ACSR) conductor per phase.

The design and construction of all line components, including poles, supports, stays, cross-arms, insulators, foundations and conductors shall ensure that these components operate safely under all service conditions.

2.5.2 BALANCED LOAD CONDITIONS Under balanced load conditions the working load shall consist of the sum total of the following, where applicable:

a) Vertical load consisting of the total force imposed by the mass of all phase and earth conductors, insulators, clamps, spacers, dampers and jumpers;

b) Transverse load, consisting of a wind pressure of 720 Pa on 60% of the projected area of all elements of the support structures, including insulators, plus a wind pressure of 720 Pa on 60% of the projected area of all phase conductors;

c) Transverse horizontal load due to the working tension in all phase and earth conductors, in still air at -5°C for the maximum deviation of the line permissible for that particular structure;

d) Longitudinal load on strain structures (where applicable) caused by all phase and earth conductors at minimum temperatures and maximum wind conditions;

e) Vertical loads due to stay wire tension;

f) Horizontal loads due to stay wire tension.

The support structure design shall be such that, when loads of 2,5 times the maximum balanced loads are applied, the structure shall not distort permanently or suffer failure of any component.

2.5.3 BROKEN CONDUCTOR (UNBALANCED) LOAD CONDITIONS Under broken conductor conditions (one phase conductor broken) the loads posed by the mass and wind-loading conductors alone may be reduced to 75% of those obtained under



balanced conditions for suspension structures. The broken conductor design loading for strain structures shall not be down rated.

Support structures shall not fail or distort permanently when loads equivalent to 1,5 times the maximum broken conductor loading is applied.

2.5.4 EXCAVATION AND BACKFILL

2.5.4.1 General Tenderers shall note that a single excavation rate for all types of material is applicable : no separate claims for other soil or rock formations will be accepted.

Rates for excavation work shall include all fuel and transport costs of any mechanical excavation aids, such as compressors, back-actors or drilling rigs, should the Tenderer intend to use these, as well as for the backfill of the excavation with cement-stabilised material, compacted in layers not exceeding 300 mm, as required.

Excavations for stay anchors shall further comply with the requirements listed under stays elsewhere in this document.

Excavations exceeding 1 500 mm in depth shall be properly protected against caving-in by suitable shuttering until they are backfilled. Trench backfilling shall be done in layers not exceeding 300 mm, which shall be properly compacted, as required.

2.5.4.2 Backfill All backfill for foundations and trenches shall be properly compacted in layers not exceeding 300 mm to a value not less than Mod 93% AASHTO. Where deemed necessary, the Engineer shall instruct the contractor to have the compaction tested for compliance by a soil testing laboratory.

Where required, backfill soil for poles and stay anchors shall be stabilised with 10% by volume with cement. Rates provided for excavation and backfill for foundations shall include the provision and mixing of the stabilising cement with the backfill material.

2.5.5 WOODEN POLE STRUCTURES

2.5.5.1 General Wooden poles shall be to SANS 753. The poles shall generally be 11 000 mm long, and shall have minimum top diameters of 160 mm.

Where required, 13 000 mm poles shall be used at road crossings to achieve the minimum specified road clearance.

Conductor clearance shall be improved by using A-frame conductor supports and vertical line post insulators where this is inadequate as a result of undulations in the natural ground level.

When loaded to cantilever loads of 5,35 and 6,2 kN, the fibre stress shall be 55 MPa.

Poles shall be preserved, impregnated and marked as per SANS 987.

Vertical poles shall comply with group A specifications as per SANS 753.

2.5.5.2 Standards With regard to MV line work, the latest edition, revision or amendment of the following standards shall be strictly adhered to:

a) The SANS 10280 : Code of Practice for Overhead Power Lines for conditions prevailing in South Africa, as amended and revised.

b) The Guide Book for overhead lines as provided by ESCOM.



c) All regulations as imposed by Telecom Namibia. Written permission to cross all existing services shall be obtained from all relevant departments.

d) The Machinery and Occupational Safety Act and Regulations (Act No. 6 of 1983).

2.5.5.3 Pole Installation After all insulators have been fitted to the pole, and the hole has been excavated to the correct depth, the pole shall be placed into the hole, taking care not to spill excavated soil into hole.

While the pole is held in position, sightings with two optical survey instruments shall be taken to ensure that the pole is completely vertical.

Backfilling with the stabilised backfill shall be done in layers of 300 mm, which shall be properly compacted.

The pole shall continuously be monitored for plumbness, using the survey instruments, which shall remain in place until the pole has been properly installed.

Should any doubt arise regarding the suitability of type of soil encountered during the digging of foundation holes, the Engineer shall be immediately informed, and no work on pole installation shall proceed until the Engineer has approved the foundation construction.

Poles shall not be installed without the Engineer's approval of the foundation hole and type of foundation to be used.

2.5.5.4 Pole Protection Sharp-edged rocks, at least 300 mm diameter, shall be placed in a solid circle of diameter not less than 6 m round the base of all poles located in areas where elephant and rhino may occur.

2.5.6 FOUNDATIONS The detail design of support foundations, where applicable, shall be submitted to the Engineer together with load calculations. It is the Contractor's responsibility to do soil tests in order to establish load bearing and chemical properties of the soil along the route. These test results shall also be submitted to the Engineer together with foundation drawings.

If special types of foundations such as rock foundations are used these shall be approved subsequent to a site inspection where the problems will be examined on site.

All steel work below ground shall also be galvanised. Steel work cast into concrete shall be securely keyed.

2.5.7 NUMBER OF CIRCUITS AND CONDUCTORS The line shall be designed to carry three single-phase ACSR conductors. No earth conductor is required for the line.

2.5.8 CLEARANCES AND CROSSING SPANS Clearances shall generally conform to the South African Machinery and Occupational Safety Act (MOS Act) and shall be as follows :

Nominal System Voltage

MAX System Voltage

Minimum Safety

Clearance

Above Ground outside

Above Ground inside

Road & Rail

Clearance

Communication

Power & other

Buildings & other

Structures



(kV) (kV) Townships Townships Lines

11,0 12,0 0,20 5,1 5,5 6,3 0,8 3,0

22,0 24,0 0,32 5,2 5,5 6,4 0,9 3,0

33,0 36,0 0,43 5,3 5,5 6,5 1,0 3,0

The clearances shall be the minimum clearance (in metres) at 50°C and under wind pressures of 500 Pa.

No joints will be permitted in spans crossing other services such as roads, power lines and telecommunication lines.

Crossing spans shall not cross directly over poles or structures supporting other services.

Arcing horns or armour rods shall be provided on suspension structures supporting spans crossing any service, for at least three structures on both sides of the service being crossed.

One support structure shall be located as close as possible to the service being crossed, but the service or service servitude shall not be touched by the structure in the event of it overturning.

Crossing spans shall preferably cross all services at 90°, but the relative angle shall in any case not be less than 60° to the service being crossed.

2.5.9 CONDUCTOR SPACING AND ATTACHMENT HEIGHT The conductors for HPLCD structures shall be spaced such that they are at least 800 mm apart for 33 kV applications at the point of attachment (9 500 mm minimum agl) on standard single pole structures, as per the relevant standard drawings.

2.5.10 STAYS

2.5.10.1 General Termination strain structures and in-line strain structures shall be provided with two stays.

Poles at which the line route deviates more than 1° shall be strain poles.

Structures at which the line deviates more than 2° shall be provided with stays. Where the line deviation is less than 15°, two in-line stays shall be provided.

For deviations greater than 15°, two in-line stays and one bisector stay shall be provided.

For deviations greater than 30°, two in-line stays, and two bisector stays shall be provided.

For deviation angles exceeding 60°, four in-line stays and one bisector stay are required. At the 90° angle structures at the road crossing, four in-line stays and two bisector stays shall be provided.

Prop stays will not be acceptable, unless specifically approved by the Engineer.

Stay assemblies shall have a factor of safety (FOS) not less than 2,5.

Where a single stay may cause failure or deformation of the pole under normal or abnormal (broken conductor) conditions, additional stays shall be provided as required.

All metallic components of stay assemblies shall be galvanised to SANS 763.

Complete stay anchor assemblies shall comprise the baseplate, stay rod (at least 2 400 mm long) turnbuckles, or adjustors, thimbles, washers, locknuts, guy grip dead-ends and pole-top make-offs. Sufficient margin (at least 200 mm) for future adjustment of the turnbuckle or stay tension adjustor shall be provided.



2.5.10.2 Stay Wires Stay wires shall consist of at least 7/3,25 galvanised stranded steel wires, Grade 700 MPa, with a calculated breaking strain not less than 61 kN.

2.5.10.3 Stay Anchors Stays shall be provided with galvanised steel anchor base plates at least 380 x 380 x 6 mm in size, with 25 mm stay rods.

Base plates shall be buried at vertical depths of at least 1 500 mm, with the hole excavated in such a way to allow the rod and base plate to be installed at 90° to each other, with the base plate abutting against undisturbed soil at an angle of 45° to the vertical. Stay plates shall be reinforced and provided with a suitably sized washer to ensure that the load is spread evenly over the base plate without deformation.

Base plates shall not be installed in such a way that stay wires run parallel to each other, in cases where more than one in-line or bisector stay are required, but shall be placed symmetrically at least 1 500 mm on either side of the extended line direction to be stayed, ie at least 3 000 mm apart.

Should it become apparent that a stay anchor is located in yielding or suspect ground, the Engineer shall be notified immediately, and no installation work shall commence until the Engineer has approved a proposed alternative installation.

Stay rods shall not be bent.

2.5.10.4 Stay Insulators Stays shall be provided with stay insulators, matched to the tensile strength of the staywire and the system voltage.

2.5.10.5 Stay Hardware "Preformed" products may be used in stay anchors, provided that the mechanical strength matches that of the stay wire.

Installation shall be done according to the manufacturer's specifications.

"Crossby" clamps will not be accepted on final installations.

2.5.10.6 Anti-climb Guards Where two stays are installed parallel to each other, anti-climb guarding, in the form of barbed wire securely wrapped around the stay wire from a height of 2 000 mm to 4 000 mm above ground level, shall be provided.

2.5.11 A-FRAME CROSS-ARMS Galvanised steel A-frames shall be used to support the MV overhead line, in conjunction with porcelain suspension or strain insulator assemblies, as required.

A-frames shall be strain and suspension type, as required by the application, and clearances shall be for the appropriate system voltage.

2.5.12 LINE INSULATORS

2.5.12.1 General Insulators shall comply with SANS 60383 and SANS 066, and shall be of the porcelain type for suspension and strain assemblies, as well as for standoff units on strain structures, where required. Factors of safety shall be at least 2,5 based on the failing load.

Tenderers shall provide full technical information on the type of insulators they intend to use with their offer.



The surfaces of insulators shall be completely smooth to prevent adhesion of contaminants. Materials shall be UV-resistant silicone rubber or glazed porcelain.

The following insulators are required :

DESCRIPTION 33 kV : MANUFACTURER / TYPE

Long Rod Cullinan / EP 1044, 40 kN

Line Post Type 1 Cullinan / EP 480, 4 kN

Line Post type 2 Cullinan / EP 306, 12,5 kN

Stand-off Cullinan / EP 480, 4 kN

Line post type 1 insulators with single side ties shall be used in normal spans : type 2 insulators with twin ties shall be used for road crossing spans and two adjacent poles in both directions of the crossing span.

Insulators shall be provided with all mounting and attachment hardware, and shall be installed to the manufacturer’s requirements.

2.5.12.2 Line Post Insulators Line post insulators shall be installed vertically on galvanised steel cross-arms or horizontally onto poles, using M20 spindles, washers and nuts. Curved washers shall be used between all steel and wood surfaces.

Conductors shall be attached to the post insulators with pre-formed galvanised steel side ties and neoprene padding tube, as per the manufacturer’s recommendation.

2.5.12.3 Long Rod Insulators Long rod insulators shall be installed with the pole end clevis vertical, using galvanised steel eye bolts and retaining pins with hump-back split pins and washers between the pin and insulator steelwork.

Conductors shall be attached to the line end of the insulator by means of horizontal clevis thimble attachments and pre-formed conductor dead-ends, complying with the manufacturer’s instructions.

2.5.13 INSULATION CO-ORDINATION Care shall be taken to provide uniform insulation co-ordination on all overhead line support structures as follows :

MV poles shall be provided with BIL down conductors and earth electrodes consisting of 3/3.35 mm stranded galvanised steel wire stapled to the pole at intervals not exceeding 500 mm, with at least five shorted turns round the pole butt., which shall be taken up the pole and terminated on a band of stainless steel strapping located 400 mm below the lowest insulator. The three insulator attachment spindles, nuts and washers shall be short-circuited by a length of similar steel wire, and terminated 100 mm below the lowest insulator, providing a BIL gap of 300 mm on ALL pole-top steelwork. Refer to attached drawings for details.

2.5.14 PHASE CONDUCTORS

2.5.14.1 General Phase conductors shall be of aluminium, steel reinforced type, complying with SANS 182-3.

2.5.14.2 Phase Conductors ACSR conductors shall be as follows :



a) Code / size RABBIT

b) Conductors/phase one

c) Current capacity 254 A per conductor

d) Conductor area 52,88 mm2

e) Stranding 6/1/3,35 per conductor

f) Ultimate strength 18,5 kN

2.5.14.3 Installation Conductors shall be carefully handled during installation to avoid damage, kinking or twisting. Conductors shall not be dragged over the ground. Drums shall be properly supported on a spindle during installation.

Dynamometers shall be used to tension conductors to the initial installation tension according to sag charts, compensated for the ambient temperature at installation. Pulleys shall be used on suspension insulators until all tensioning has been completed.

Clearances to ground or other structures or obstacles shall be as indicated elsewhere in this document, and shall comply with the SAIEE Code of Practice and the MOS Act.

Conductor movement in the longitudinal and lateral direction shall be facilitated by the proper choice of clevis and tongue type fittings and adaptors.

Midspan joints shall be minimised as far as possible. Where the use of midspan joints is approved, these shall be of the current-carrying, compression type, having a mechanical strength equal to, or greater than, the ultimate strength of the conductor used.

Joints will not be allowed in spans crossing roads, railway lines, communication or power lines and other important services.

Excessive loading of poles and their components shall be avoided. Temporary stays shall be erected where necessary to avoid damage to equipment or installations.

No additional payment for the provision of temporary stays, scaffolding, pulley poles or other devices required during the installation of conductors will be considered; Tenderers shall include the provision, installation and removal of these in their rates.

2.5.14.4 Conductor Clamps and Line Accessories Wire-wrap dead-ends shall be used to connect conductors to strain insulators. Jumpers shall in all cases be long enough to ensure proper connection. PG clamps shall NOT be used to connect jumpers: crimped ACSR joints on jumper connections shall be the only method permissible.

2.5.15 PROJECT RECORDS Complete and accurate records of each line strain section's tensioning, sag, temperature, conductor jointing and cable lot/drum information, as well as footing earth resistances, as measured, and commissioning test results shall be handed to the Engineer with the contract documentation and drawings at the conclusion of the contract.

2.6 L IGHTING ARRESTORS Line class lighting arrestors, of the gapless zinc-oxide type, rated for 11 kV system voltage shall be installed at transformers and at each line termination point, including overhead to underground transition points. Arrestors shall be as follows:

ITEM REQUIREMENT



a) System Voltage (line) 33 kV

b) Maximum system voltage 36 kV

c) System BIL 200 kV

d) Creepage distance (minimum) 1 200 mm

e) Current rating 10 kA

f) Disconnector Yes

Arrestors shall be securely mounted on hot-dip galvanised steel brackets, with arrestor centre spacings not less than 250 mm. Minimum clearance to earth of any live component shall not be less than 300 mm. The connection to earth shall be by means of three individual lengths of 50 mm2 BCEW, connected to the earth terminal of each arrestor on one end, and with three individual line taps on the other end to a 70 mm2 insulated copper earth conductor (ICEC) connected to the centre of a lighting arrester earth electrode, which shall consist of four vertical copper clad earth spikes 1 200 mm long, installed 3 000 mm apart in a square formation, interconnected by 70 mm² BCEW buried 1 000 mm below ground level.

2.7 FUSE L INKS

2.7.1 SCOPE This specification covers distribution open fuse cut-outs (or drop-out fuses) of the expulsion type to the standards of NRS 035 : 1994, intended for overload and short circuit protection of distribution equipment of 33kV networks.

2.7.2 GENERAL DESIGN ITEM REQUIREMENT

a) System Voltage (line) 2 50 Hz 33 kV

b) Maximum system voltage 36 kV

c) System BIL 200 kV

d) Creepage distance (minimum) 910 mm

e) Contact current rating 150 A

f) Finish All ferrous metal parts shall be galvanized to SANS 32 and SANS 121

g) Operation Suitable to be operated by link stick from ground

h) Fuses HRC expulsion type, minimum rupturing capacity of 150MVA. Fuses to give positive indication on failure and to make provision for easy replacement from ground level by means of a link stick

2.7.2.1 Installation Fuse switches shall be installed on cross-arms of galvanized steel to SANS 32 and SANS 121, suitably drilled and fitted with support brackets.

Where possible, fuse switches shall be installed on the last pole before the transformer installation but not more than 3 spans away and always completely visible for the position of the transformer. Fuse switch installation on the transformer structure are to be avoided.



The drop out fuse cross-arm shall be installed at least 6 500 mm above the natural ground level.

The L-bracket for steel cross-arm mounting shall be used and shall be in accordance with NRS 035.

2.7.2.2 Labelling The drop-out fuse assembly label shall comprise of the car number plate type, at least 200 mm wide and 200 mm high, the largest possible characters shall be used, indicating the name and type of cut out, i.e. DOF No 5, FUSES or SOLID LINK with amperage where applicable. The label shall be screwed to the pole 1 000 mm below the drop out fuse assembly.

2.8 LOAD-BREAK SWITCHES Load-break switches shall comply with the requirements of drop-out fuse links with the exception that arcing contacts shall be included in the design of the unit to enable the link to be opened under load.

2.9 POLE-MOUNTED LV METERBOARD

2.9.1 GENERAL Pole distribution boards shall consist of weatherproof 3CR12 or galvanised or painted corrosion resistant steel boxes, 1.5 mm thick sheet steel, with lockable doors, internal busbars, main and supply circuit breakers and streetlighting controller units, mounted at 1 600 mm above ground level.

Meter boards shall be supplied installed and mounted strictly to manufacturer’s specification.

2.9.2 SPECIFIC REQUIREMENTS FOR METER BOARDS a) Manufacturer / material Aluex, 3CR12, 1,5 mm thick sheet steel

b) Type Type A, B or C (see below)

c) Mounting Pole (1 500 agl to bottom of board)

d) Dimensions 650 x 400 x 300 mm ( HxWxD)

e) Wiring Single or 3 phase, neutral, earth, 200 Ampere

f) Incoming MCCB

i) Type A (16 kVA transformer) One, SP, 80 A, 10 kA, ABB, JSO

ii) Type B 25 kVA transformer

50 kVA transformer

One, TP, 40 A, 25 kA, ABB, JSO

One, TP, 80 A, 25 kA, ABB, JSO

iii) Type C 100 kVA transformer One, TP, 150 A, 25 kA, ABB, JSO

g) Metering

i) Type A (16 kVA transformer) Single phase, 80 A, kWh meter, Landis & Gyr, to SANS 61358

ii) Type B (50 kVA transformer)

(25 kVA transformer)

Three off single phase, 80 A, kWh meters, Landis & Gyr, to SANS 61358



iii) Type C

(100 kVA transformer)

One, three phase maximum demand meter, Landis & Gyr with 3 x 150/5 A CT’s, meter voltage circuit protection facilities and 3-phase + neutral LV surge arresters and isolator

h) Doors One, lockable

i) Colour “NOSA” orange (SANS code B26, Light Orange), powder-coat painted

j) Labelling Danger labels, customer name / number

2.10 LV CABLES 50 or 35 mm² 4-core, copper conductor, PVC-insulated, steel wire armoured LV power cable shall feed the LV meterboard from the transformer LV terminals.

SECTION 1 STANDARD TECHNICAL SPECIFICATION Power specifications.pdf · SECTION 1 STANDARD TECHNICAL...

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