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Contents Page

1. Scope of supply/validity of the specification .................................................................21.1. Switchgear.........................................................................................................21.2. Overhead line, cable and transformer terminals............................................31.3. Instrument transformers....................................................................................41.4. Low voltage equipment ....................................................................................4

2. Standards .........................................................................................................................52.1. Switchgear.........................................................................................................52.2. Overhead line, cable and transformer terminals............................................62.3. Instrument transformers....................................................................................62.4. Low voltage equipment ....................................................................................62.5. Circuit-breaker ..................................................................................................62.6. Disconnector and earthing switch ...................................................................6

3. General design/safety requirements..............................................................................73.1. Switchgear.........................................................................................................73.2. Overhead line, cable and transformer terminals............................................93.3. Instrument transformers....................................................................................103.4. Low voltage equipment ....................................................................................103.5. Circuit-breaker ..................................................................................................133.6. Disconnector .....................................................................................................143.7. Earthing switch ..................................................................................................14

4. Quality assurance/testing and inspection......................................................................165. Packing/transport and storage.......................................................................................186. Installation/site testing......................................................................................................197. Maintenance/spare parts and tools................................................................................208. Documentation/nameplates............................................................................................21

Appendix/technical data sheets/drawings

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1. Scope of supply/validity of the specification

1.1. Switchgear

1. This specification covers the requirements for the supply of a hybrid outdoorswitchgear for the rated voltage specified in the "Technical Data Sheets". Theswitchgear shall be completely quoted, including all components required forproper operation unless specifically excluded herein.

2. The specification covers the design, ratings, testing transport and packing offactory assembled switchgear bays. The specification lays down general aspects.More detailed and specified data are contained in the drawings, data sheets andother documents that form parts of this specification.

3. The layout shall be generally as shown on the drawings however, subject to theprovisions of this specification and the approval of the engineer, they may beadjusted as necessary to suit the manufacturer's standard design.

4. Standard designs and types of bidder's manufacturing program are preferred,provided they meet the requirements of this specification and serve the intendedpurpose. The Bidder shall provide at least ... references over a period of ....yearscarried out with equipment of the same or higher technical performance asrequired herein. The Bidder shall confirm, that no former contract featuring theoffered equipment was subject of cancellation due to its quality.

5. The bidder may also offer alternative solutions which deviate from thespecification.

6. The switchgear described in this specification is intended for continuous duty atthe specified ratings and under the specified ambient conditions 24 hours a day,365 days a year unless indicated otherwise. Further details can be clarified innegotiations between the supplier and the purchaser.

7. All supporting structures for the switchgear bays, for the related overhead line-,cable- and transformer-connection enclosures shall be a part of bidder's supply.Foundations and embedded steel for reinforcement and levelling shall be suppliedby others.

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8. The field-installation and commissioning of the switchgear is not a part of thisinquiry. Special tools and equipment that are required to perform these services(e.g. gas-service carts and HV test equipment) shall be offered separately in thebid.

9. The initial gas filling of the entire switchgear including the usual losses duringcommissioning shall be included in the offer.

10. If necessary, SF6-insulated arresters shall be offered by the bidder along with theswitchgear.

1.2. Overhead line, cable and transformer terminals

1. The terminations for overhead lines shall be quoted completely with SF6-to-airbushings. Interconnecting, gas-insulated busducts and their supports are part ofthe switchgear supply. Their individual lengths shall be adjusted to the preliminarylayout sketch included with the inquiry. The overhead line terminal is a part of theoverhead line supply.

2. The gas-insulated cable connection enclosure and the associated conductors arepart of the switchgear supply. Stress cones and cable accessories are part of thecable supply. Cables and cable terminations are not part of this inquiry. The biddershall submit drawings that clearly show the limits of his scope of supply. Theinterfaces suggested by the bidder should confirm to the requirements of the IECrecommendations for cable terminations stated in paragraph 2.

3. In case power transformers are to be connected to the switchgear via gas-insulated conductors, the gas-insulated connection bus with the terminal for theconductor coming from the transformer shall form a part of the switchgear. Theconductor coming out of the transformer including the associated SF6-to-Oiltransformer bushing are not part of this inquiry. Along with this offer, the biddershall submit suitable illustrations and sketches clearly showing the limits of hisscope of supply. Based on the layout sketches which form a part of thisspecification, the bidder shall supply all necessary interconnection modules.

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1.3. Instrument transformers

1. Both, voltage and current transformers, form a part of the scope of supply and shallbe quoted along with the switchgear, confirm to the specified data.

1.4. Low voltage equipment

1. Cubicles containing the control and interlocking equipment shall form a part ofeach switchgear bay and must be included in the quotation. Control cablesbetween the individual devices of switchgear bay and the associated controlcubicles form a part of this inquiry.

2. The auxiliary power supply for control, indication, various drive mechanisms andanticondensation heating shall be provided by the purchaser. The availablevoltages are listed in the appendix. The bidder may suggest other voltages if thesecorrespond to the standard models of the manufacturer; however, this is subject toapproval by the purchaser.

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2. Standards

1. The construction, the testing and the ratings of the switchgear must correspond tothe latest edition of the standards specified below.

2. The proposed switchgear may conform to the standards of the country ofmanufacturer, provided these standards are based on, or comparable to thefollowing preferred standards. Each bidder suggesting others than the preferredstandards must clearly state the standards to which his equipment conforms andindicate all deviations from the preferred standards which may have an effect onthe function and the ratings of the switchgear.

3. Compliance by the manufacturer with the standards of this specification does notrelieve him from the responsibility of supplying switchgear and accessories ofproper design, electrically and mechanically suitable for fulfilling the operatingguarantees at the specified service conditions.

4. If, in the opinion of the bidder, there are any conflicts between these standards, thedata sheets and this specification, these contradictions shall be brought to theattention of the purchaser.

2.1. Switchgear

IEC 60694 (Common clauses for high-voltage switchgear and control gear standards)

IEC 60517 (High-voltage metal-enclosed switchgear for rated voltages of 72.5 kV andabove)

IEC 60376 (Specification and acceptance of new sulphur hexafluoride)

IEC 60480 (Guide to checking of sulphur hexafluoride taken from electricalequipment)

IEC 60099-4 (Part 1: Non-linear resistor type arresters for AC systems)

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2.2. Overhead line, cable and transformer terminals

IEC 60137 (Bushings for alternating voltages above 1000 V)

IEC 60859 (Cable connections for gas-insulated metal-enclosed switchgear for ratedvoltages of 72.5 kV and above)

2.3. Instrument transformers

IEC 60044-4 (Instrument transformers. Measurement of partial discharges)

IEC 60185 (Current transformers)

IEC 60186 (Voltage transformers)

2.4. Low voltage equipment

IEC 60439 (Factory-built assemblies of low-voltage switchgear and control gear)

2.5. Circuit-breaker

IEC 60056 (High-voltage alternating-current circuit-breakers)

IEC 60427 (Report on synthetic testing of high-voltage alternating-current circuit-breaker)

2.6. Disconnector and earthing switch

IEC 60129 (Alternating-current disconnectors (isolators) and earthing switches)

IEC 61128 (Alternating-current disconnectors. Bus-transfer current switching bydisconnectors)

IEC 61129 (Alternating-current earthing switches. Induced current switching)

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3. General design/safety requirements

3.1. Switchgear

1. The switchgear must provide a maximum degree of safety for the operators andothers in the vicinity of the switchgear under all normal operating conditions andunder fault conditions (short-circuit).

2. It must be impossible to touch any live part of the switchgear unwillingly, i.e. withoutthe use of tools or brute force.

3. An operator standing in the normal operating position should not be endangeredby any moving external part of the switchgear.

4. Interlocks must be provided to prevent any maloperation of the switchgear.

5. If in spite of all possible safety measures an arc should occur, the following isrequired:

- The effects of an internal arcing fault must be limited to the related gascompartment by bushings.

- Each gas compartment must have its own pressure relief device to provideinstant and safe discharge of accidental overpressure during internal arc.Rupture diaphragms shall be preferably used as pressure relief mechanisms.Such gas discharge must be directed away from the normal operationposition of the switchgear so that persons standing there are notendangered. If necessary, diverter nozzles shall be provided to ensure thatthe gas is directed away from this position. Internal relief devices betweenadjacent compartments are not acceptable.

- All earthing connections must remain operational.

- The enclosure of the switchgear must withstand the thermal effects of an arcat the full rated short-circuit current until the nearest protective relay hastripped.

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6. To limit the effects of an internal arc the switchgear shall be suitably subdividedinto individual arc and gas-proof compartments, at least for

- busbar isolators

- circuit breakers

- line isolators and interfaces (OHL, cable, transformer)

- potential transformers

7. The following requirements are derived from or are in addition to the technical datagiven in the appendix:

- The bracing of all components subject to mechanical forces caused by short-circuit currents shall correspond to the values given in the data sheets; theymust, however, withstand the effects of at least 2.5 times the ratedsymmetrical short time withstand current.

- The thermal rating for all current carrying parts and insulating materials shallbe a minimum of 1s for the rated short time withstand current.

8. Aluminium or aluminium alloys shall be used exclusively for the enclosures, exceptfor special components like bellow compensators.

9. Manufacturers standard paint colour shall be used; a satin mat finish with a highscratch resistance is preferred.

10. Pipings between gas compartments and gas monitoring and maintenance fittingsare not acceptable. Those fittings for gas monitoring and gas supply shall bemade of copper, aluminium, brass or high grade steel.

11. Joints of different metals that could lead to electrolytic corrosion must be avoided.

12. All gas compartments shall be fitted with filter material which absorbs the residualand entering moisture inside the high-voltage enclosure. Filters in gascompartments with switching devices must also be capable to absorb the gasdecomposition products resulting from the switching arc.

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13. Single sealings of O-ring type shall be used for sealing the connections betweenthe switchgear modules. The guaranteed leakage rate of each individual gascompartment must be less than 0,5 % p.a.

14. The arrangement of the switchgear offered must provide adequate access forchecking and maintenance. However the space needed for the equipment shall bekept to a minimum. Therefor the centre distance between each bay shall notexceed 1,2 m, whereas the bay width is less than 1,2 m.

15. The conductors shall be made of aluminium alloy or electrolytic copper. Both, theconductors as well as the contacts for the conductor connections must bedesigned for the continuous rated current of the switchgear under the ambientconditions stated in the appendix and shall not exceed the permissibletemperature rise.

16. All components of the switchgear which are on ground potential shall be electricallyinterconnected.

17. The layout shall sufficiently take care to the thermal contraction of the assembly bythe provision of expansion joints. Expansion joints shall be at least placed inbetween any bay section of the busbar.

3.2. Overhead line, cable and transformer terminals

1. SF6-air bushings shall be equipped with a Silicon compound insulator jacket. Theratings shall comply with the technical data of the switchgear.

2. Each cable or transformer connection enclosure shall provide a facility for isolatingthe cable or transformer bushing from the switchgear and for application of a high-voltage test probe for dielectric testing.

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3.3. Instrument transformers

1. All instrument transformers must be suitable for continuous operation wheninstalled on the switchgear under the ambient conditions stated in the appendix aswell as under all rated and short-circuit conditions stated in the data sheets or inthe single line diagram.

2. Toroidal current transformers of the single or multi-ratio type, mounted inside thehigh-voltage enclosure with grounded cores are preferred.

3 The current transformer data are listed in the single line diagram.

4. Current transformers must have secondary terminals outside the high-voltageenclosure, mounted in suitable, accessible terminal boxes. All secondary leads ofall current transformers must be wired to shorting-type terminals.

5. Voltage transformers shall be of the metal-enclosed, gas-insulated inductive orRC-divider type (when respective transducers are available). They are to bemounted directly on the high-voltage enclosure with plug-in contacts to allow easyremoval.

6. The voltage transformer data are stated in the single line diagram.

7. The secondary terminals must be located in accessible, grounded terminal boxeson the voltage transformer itself.

3.4. Low voltage equipment

1. All control circuits shall be manufacturer's standard for the application on hand, butshall be approved by the purchaser. Special functions shall be included if indicatedin the single line diagram, or if shown in special control specificationsaccompanying this inquiry.

2. All local control functions such as

- Switchgear interlocking functions- Over current protection means for Low voltage equipment- Local operation of the switchgear- Indicating and measuring equipment

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must be located either at the bay or in the local control cubicle. It must have degreeof protection IP 54 at least.

3. All switchgear shall be interlocked by electromechanical, electrical or electronicequipment. These interlocking facilities shall be located in the local control cabinetof each bay. They must provide absolute and reliable protection against anypotentially harmful maloperation of the switchgear. The following functions must beprovided:

- The operator must be forced into the only safe and logical sequence toactuate circuit-breakers, switches, disconnectors and earthing switches.

- The actual, completely closed or completely opened position of all switchingdevices must be checked before and after each move.

- Implementation of logic checks and issuing the resulting signals ENABLE orBLOCKED for the switching device.

- Manual local operation and automatic remote operation for all essentialfunctions.

- Local emergency unlocking equipment via safety key switch under fullresponsibility of the operator.

4. The gas monitoring of each bay must be carried out for all three phases commonly.It must be located directly at the gas compartment monitored. The gas monitoringmust have suitable fittings and valves to fulfil the following functions:

- for circuit-breaker compartments: rough indication and monitoring of the gasdensity with alarm for drop in density, lock out of the circuit-breaker in case ofa further drop.

- For switchgear gas compartments: rough indication and monitoring of thegas density in two stages.

- Additional monitoring of the gas density with alarm in case of increase ofdensity of gas compartments neighbouring compartments with a higherdensity.

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- Access for evacuating, filling and topping via gas service cart.

5. All control and monitoring equipment for the circuit-breaker and its accessoriesshall be installed in a local drive control cubicle. The related control wiring shall bewired to plug-in connectors. The cabinet must have degree of protection IP 54 atleast.

6. Each circuit-breaker shall be provided with at least two trip coils. Provisions formanual emergency operation must be made. All circuit-breakers must be suitablefor remote control. Main contact position of all three poles must be indicated bydirectly activated auxiliary position switches with at least 5 NO and 5 NC contactswired to a plug connector in the local control panel for customer's use. Each circuit-breaker shall be provided with an operations counter.

7. Finely-stranded copper wire of at least 1.5 mm2 cross-section shall be used withinthe control cabinet for all control wiring. Manufacturer's standard crimp-typeterminations and screw line-up terminals suitable for a cross-section of at least 2,5mm² proofed against creepage currents shall be used. All interconnecting wiringmust be suitably protected against mechanical damage, e.g. by routing them inprotective channels or pipes.

10. Each control circuit - except the tripping circuit - shall be protected by suitable overcurrent protection means which provide an alarm signal when operated.

11. Anti-condensation heaters shall be provided in the control cabinets, in theoperating mechanism housings of disconnectors, earthing switches and circuit-breakers.

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3.5. Circuit-breaker

1. The circuit breaker shall be of three phase encapsulated type. The technical datalisted in the enclosure under "switchgear, general" are valid unless otherwisestated.

2. Only single-pressure, single-break, self-compression -type circuit-breakers withSF6 as arc-quenching and insulating medium and with a minimum-maintenancecontact system are acceptable.

3. The breaker operating mechanism shall be of the spring type. Pneumatic orhydraulic mechanism are not acceptable. It shall be suitable for triple poleautomatic reclosure.

4. The operating mechanism shall be capable of performing a complete O-0,3s-CO-3min-CO IEC sequence. On failure of the drive motor or breakdown of the auxiliaryvoltages tripping of the breaker shall still be possible.

5. A mechanical indicator shall display the position of the main contacts.

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3.6. Disconnector

1. The technical data listed in the enclosure under "switchgear, general" are validunless otherwise stated.

2. The disconnectors shall be of the three-phase encapsulated type. All switches shallbe three-phase linkage-operated by a maintenance-free self-contained electricmotor.

3. The actual position of each disconnector and earthing switch shall be indicated bymechanically coupled auxiliary switches with at least 4 NO and 4 NC contacts.

4. Mechanical indicators connected directly and permanently to the drive mechanismshaft are required to display the actual switch position.

5. Provisions for emergency manual crank operation shall be made. Whenever thecrank is inserted in the drive mechanism it shall be impossible to operate thedevice electrically.

6. Disconnector and related earthing switch shall be mechanically interlocked to eachother.

3.7. Earthing switch

1. The technical data listed in the enclosure under "switchgear, general" are validunless otherwise stated.

2. The earthing switches shall be of the three-phase encapsulated type. All switchesshall be three-phase linkage-operated by a maintenance-free self-containedelectric motor.

3. Earthing switches on the line side of overhead line feeders must have make-proofcontacts and high-speed operating mechanisms so that they are suitable forswitching capacitive and inductive currents as well as for closing on to a fault.

4. The actual position of each earthing switch shall be indicated by mechanicallycoupled auxiliary switches with at least 4 NO and 4 NC contacts.

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5. Mechanical indicators connected directly and permanently to the drive mechanismshaft are required to display the actual switch position.

6. Provisions for emergency manual crank operation shall be made. Whenever thecrank is inserted in the drive mechanism it shall be impossible to operate thedevice electrically.

7. Earthing switches and the related disconnector shall be mechanically interlockedto each other.

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4. Quality assurance/testing and inspection

1. Type-tests shall have been successfully carried out and been suitably documentedfor the switchgear type proposed by the bidder. Test certificates shall bepresented by the bidder upon request.

2. Routine tests of each switchgear bay have to be successfully carried out inaccordance with the standards listed in chapter 2.1. Routine tests on individualcomponents for which other IEC recommendations exist, shall be carried out inaccordance with these recommendations. Special tests may be agreed uponbetween the manufacturer and the purchaser prior to order placement.

3. Routine factory tests, minimum:

- Pressure test on each enclosure. The test pressure for all cast housings shallbe twice and for all welded housings 1.5 times the design pressure. Gastightbushings between the gas compartments must be able to withstand twice theservice gas pressure at one side against 0 bar (absolute) on the other.

- At least 10 % of all welds must be subjected to nondestructive X-ray orultrasonic methods (random checks, according to pressure vesselregulations).

- Partial discharge test on each insulator before installation in the switchgear.No measurable partial discharge (less than 10 pC) shall occur on theinsulator when 110 % of rated voltage is applied. This test must be carriedout on each post type insulator and bushing used in the switchgear.

- Gas leakage test on each transport unit. A Helium gas leakage test with asuitable accuracy must be carried out on each transport unit before dispatch.

4. The following tests shall also form a part of the routine tests. These tests may bewitnessed by buyer's authorised representatives on a noninterference basis:

- Power frequency voltage dry test and partial discharge measurements oneach transport unit

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- Insulation test with 2 kV on all auxiliary circuits

- Resistance measurement of the main circuits of each transport unit

- Mechanical testing of the switching devices

5. The purchaser must be informed at least two weeks in advance regarding testswhich he desires to witness. The purchaser shall immediately be informed of anychanges in the testing schedule.

6. Authorised representatives of the purchaser shall be allowed access to all thoseareas in the manufacturer's factory where the equipment covered by this contract isproduced at all reasonable times for purposes of inspection and obtaininginformation on the progress of work.

7. Acceptance by buyers' representatives of any equipment shall not relieve themanufacturer of his performance guarantees or from any of his other obligationsresulting from the order.

8. The quality assurance system shall be based on and certified to ISO 9001.

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5. Packing/transport and storage

1. The size of transport units shall be as large as possible so as to reduce theamount of field installation work. Switchgear bays shall be transported ascompletely assembled units ready to be lined up into a switchgear at site. Auxiliarycabinets with secondary equipment shall be transported as completely assembledunits.

2. The type of packing used must be suitable for the means of transportation usedfrom the manufacturer location to the installation site.

3. The packing must, if required, be suitable for outdoor storage of the equipment. Inthis case, sufficient drying agent shall be provided in the packing to absorbcondensed moisture.

4. Care shall be taken to seal off connecting flanges of the individual switchgear bayswhich are not yet connected to prevent damage and ingress of contamination intothe gas compartments. Machined sealing surfaces must be suitably protectedagainst mechanical damage and corrosion. Sealing surfaces which are exposedto the atmosphere during transport must be protected by a protective coating (suchas Tectyl) which can be pealed or washed off during installation.

5. As far as possible the modules shall be prefilled with gas. The remaining insulatinggas for the initial filling of the switchgear shall be transported separately inapproved steel cylinders marked according to international regulations.

6. All interconnecting control cables which are not directly mounted on the bay shallbe packed separately and suitably marked.

7. The static filters provided for the inside of gas compartments which are notprefilled shall not be installed before transportation but separately packed inairtight sealed tin cans and marked suitably.

8. Marking of transport containers must be approved by the purchaser. Guidelines forspecial marking must be followed meticulously to ensure positive identification atthe job site.

9. A packing list must be provided for each individual packing unit to enable thepurchaser's personnel to identify the unit clearly at site.

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6. Installation/site testing

1. The design of the switchgear bays shall minimise assembly work duringinstallation. Preference is given to completely factory-assembled switchgear bayswhich require busbar interconnection and connection of the cable or overhead lineon-site only.

2. For installation and handling of the switchgear, the use of a auto crane or hoist witha capacity of 1.5 t shall be sufficient.

3. The bidder shall state in his offer the type of tests he will carry out at site.Acceptance tests on site after installation of the complete switchgear must beseparately agreed between the manufacturer and the purchaser.

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7. Maintenance/spare parts and tools

1. The maintenance intervals of circuit-breakers shall not be less than 18 rated short-circuit current interruptions, 6000 rated current interruptions or 25 years ofoperation what ever is earlier. Maintenance activities shall comprise only simpleinspections and no exchange of parts or complex adjustments.

2. Routine maintenance of external parts of the switchgear including instrumenttransformers should not be necessary at intervals of less than 5 years.

3. For routine inspections, all elements must be accessible without removal ofsupporting structures. The removal of individual enclosure parts or completeswitchgear bays must be possible without disturbing the enclosures ofneighbouring bays.

4. Accessories for proper operation of the switchgear must be included in the basicprice.

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8. Documentation/nameplates

1. Technical descriptions, data sheets, catalogues and other material submitted withthe quotation must enable the purchaser's engineers to evaluate the proposal to itscompliance with the inquired specification.

2. Layout and elevation drawings for the switchgear shall be part of the proposal.These drawings shall show the recommended clearances for safe operation andmaintenance of the switchgear including the required lifting clearances forinstallation.

3. Minimum requirements for the offer:

- Deviations from the specification of the inquiry

- Fully filled-in data sheets of the inquiry

- Single line diagram of the switchgear as a proposal in case of deviationsfrom the single line diagram of the inquiry. The necessary busbararrangement and the number of outgoing feeders including the future andfinal extensions shall be clearly shown in this single line diagram.

- Applicable design specification

- Brochures and catalogues as well as reference lists of installed switchgearsincl. customer identification and year of installation.

- Listing of the accessories included in the offer

- Listing of the Tests included in the offer

4. In case of order, the following information and data shall be submitted to thepurchaser for approval:

- Updated data sheets, diagrams and listings as required for the offer

- Certified outline and floor cut-out dimensions including the necessaryclearances for installation, operation and maintenance as well as theapproximate static loads.

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- Certified drawings of embedded levelling and supporting steel parts ifrequired by the design.

- Location of all devices, busbars and connections for the power cables andoverhead lines.

- Circuit diagrams and interlocking sequences as agreed upon

- Instrument transformer data

- Time schedule

- Location and identification of spare parts

- Installation, operation and maintenance instructions

5. Copies of all routine test certificates shall be made available to the purchaser ifrequired.

6. All technical data provided for this equipment must show the switchgear asspecified and ordered. If any modifications in the switchgear are carried out duringexecution of the order and installation, these must be clearly shown in the drawingsand documentation. The format, the standards as well as the quality and number ofdrawings shall be in accordance with the manufacturer's standard, but shall besubject to the purchaser's approval prior to order placement.

7. All dimensions shall be only in metric SI units. Bilingual documentation isacceptable.

8. Each switchgear bay shall be provided with a nameplate in accordance to IEC517.

9. Each instrument transformer must have its own nameplate in accordance to IEC185/186. These nameplates must be fitted adjacent to the secondary terminal boxof the instrument transformer. Inside of or adjacent to each terminal box cover adurable noncorrodible circuit diagram of the instrument transformer must beinstalled with all terminal and ratio markings of the device.

10. Every auxiliary control cubicle shall be marked with the designation of the feeder itis assigned to.