SECTION 260513
TECHNICAL SPECIFICATIONS FOR ELECTRICAL WORKS - TRANSFORMER UNIT
MEDIUM VOLTAGE CABLES
PART 1 - GENERAL
1.1Related Documents
1.2Summary
1.3Applicable Codes And Standards
1.4Submittals
1.5Quality Assurance
1.6Delivery, Storage And Handling
PART 2 - PRODUCTS
2.1Manufacturers
2.2Cables XLPE
2.3Splice Kits
2.4Solid Terminations INSIDE CABLE TERMINATION END BOXES
2.5Source Quality Control
PART 3 - EXECUTION
3.1Examination
3.2Installation
3.3Grounding
3.4Field Quality Control
3.5Protection
Technical Specifications for Electrical WorksSection 260513
Revision 0Page 1 of 5Medium Voltage Cables
SECTION 260513
MEDIUM VOLTAGE CABLES
PART 1 -GENERAL
1.1Related Documents
Drawings and general provisions of the Contract, including General Conditions, Conditions of Particular Applications and Division-01 Specification Sections, apply to work of this Section.
1.2Summary
Work includes providing cables and related splices, terminations, and accessories for 11000 Volt electrical distribution system complete in accordance with Drawings and specifications.
1.3Applicable Codes And Standards
A.Medium Voltage cables shall be in accordance with:
1.SANS 10198 The selection, handling and installation of electric power cables of rating not exceeding 33 kV (all Parts).
2.SANS 97 Electric cables - Impregnated paper-insulated metal-sheathed cables for rated voltages 3,3/3,3 kV to 19/33 kV (excluding pressure assisted cable)
3.SANS 1339 Electric cables – Cross-linked polyethylene (XLPE) insulated cables for rated voltages 3,8/6,6 kV to 19/33 kV
4.IEC 60228 Conductors of insulated cables.
5.IEC 60287 Electric cables - Calculation of the current rating.
6.IEC 60332 Tests on electric cables under fire conditions.
7.IEC 60502 Power cables with extruded insulation and their accessories for voltages from 1 kV up to 30 kV.
8.IEC 60853 Calculation of the cyclic and emergency current rating of cables.
9.VC 8077 Safety of medium-voltage electric cables
1.4Submittals
Submit the following according to the conditions of the Contract and Division 01 Specification Sections with your bid:
A.Product Data: Submit Manufacturer's data for cables, cable accessories, splices and terminations.
B.Product Test Reports: Submit a report to certify Manufacturers' design and production tests indicating compliance of cable and accessories with mentioned reference standards.
1.5Quality Assurance
A.Standards Compliance: Comply with requirement of applicable local codes and IEC, standards pertaining to cables and connections. Following qualifications shall be submitted to the Engineer prior installation:
1.Installer: Engage an experienced and certified cable splicer to install, splice and terminate medium-voltage cables.
2.Manufacturer: Firms experienced and regularly engaged in manufacturing medium-voltage cable and accessories similar to those indicated and specified for this contract, with a record of successful in-service performance.
3.Tester: A person currently certified by the National Institute for Certification in Engineer Technologies to supervise on-site testing specified in Part 3.
1.6Delivery, Storage And Handling
Delivery shall be on factory reels, sealed from both ends. Store cables on reels on elevated platforms in good environmental condition and dry location.
PART 2 -PRODUCTS
2.1Manufacturers
Approved firms subject to compliance with requirements and its products have been in satisfactory use in similar services for not less than five (5) years.
2.2Cables XLPE
A. (1) Cross-linked polyethylene, 3 core, steel wire armoured or unarmoured
cables of an approved manufacture shall be used when specified, provided that full technical information is submitted with the tender. All XLPE insulated cables offered shall comply with SANS 1339. Cores shall be individually screened. The outer sheathing shall have zero Halogen emission, low smoke emission and reduced fire propagation properties.
(2)The type of cable required shall be specified in the Project Specification.
(3)The following information shall be printed on the outer sheath, in the factory, where possible:
Voltage, e.g.:11 kV
Size, e.g.:95 Cu or Al
Name of Local Authority :If required in Project Specification
The abovementioned information shall be printed on the cable at reasonable intervals
B.The medium-voltage cable shall be 98% conductivity,-electrolytic copper to IEC 228 C/2. Insulation shall be XLPE, shielded and jacketed to medium-voltage as required, grounded neutral, insulation class.
C.Temperature shall be as follows:
1.Normal, continuous operation 90°C
2.Emergency rating 130°C
3.Short-circuit rating 250°C
D.Circuit identification: Colour-coded tape (red, yellow, blue) applied between non-metallic and metallic insulation screening.
2.3Splice Kits
Approved connectors shall be provided for splices and terminal connections of all copper conductors. The connector shall fit the conductor to which it shall be connected, and the assembly shall have joint contact surfaces not less than 50%; (As recommended in writing by the splicing kit Manufacturer for specific sizes, ratings, and configuration of cable conductor and splices specified). Include all component required for complete splice, with detail instruction. Comply with IEC code.
2.4Solid Terminations INSIDE CABLE TERMINATION END BOXES
The cable through cable end boxes must be suitable for the type and sizes of cables offered.
Cable through cable end boxes for paper insulated cables must be suitable for compound filling, unless otherwise specified. No oil filling compounds will be accepted. The compound shall conform to BS 625 Class II.
The cross linked polyethylene cables shall be terminated with suitable terminating kits approved by the Engineer.
Termination for medium voltage cable shall be in the switchgear or cable entrance compartment of transformers. Type of termination fitting shall be as required to match conductor to equipment, built-up insulation and heat shrink stress cone as manufactured by Raychem (or approved equal) for the type of cable specified. Skirts shall be applied whether or not the termination is outdoors.
Solder-less pressure type lugs shall be provided with NEMA bolt hole requirements for terminating the shielded cables.
2.5Source Quality Control
Inspect and testing cables for physical damage and proper connection according to IEC 52, 60, and 230.
PART 3 -EXECUTION
3.1Examination
Check raceways and related work to receive medium-voltage cables for compliance with installation tolerances and other conditions affecting performance of the cable. Do not proceed with installation until unsatisfactory conditions have been corrected.
3.2Installation
A.Installation shall be as indicated on Drawings and according to the Manufacturer's written instructions and IEC Code.
B.Cable direct buried, unless otherwise specified furnish a bed of clean sand 100 mm deep at the bottom of trench, and save over cable. Install concrete tiles to the whole route of the cable with 50 mm thick and covering at least 200 mm over the outer edge of the cable from both sides.
C.Backfilling with selected soil and reach to 95% compaction minimum. Before reaching to the finished grade level by 500 mm install warning tape to cover the whole routes indicating "DANGER ELECTRICAL CABLES" in English.
D.At road crossings, install 150 mm uPVC concrete encasement and install warning tape only. Permanent markers shall be installed at each 50 m of cable runs, changes in direction, buried splices and cable ends.
E.Cables shall be supported at intervals adequate to prevent sag and good fixation on raceways.
F.Splices shall be installed as required by drawings and Manufacturer's recommendation and according to standard length of cable in case of long distance routes with one as a maximum in certain route.
G.Use kits which are compatible with conductor size, material and type and according to the Manufacturer's recommendations.
H.Install terminations at ends of conductors and seal multi -conductor cable ends with standard kits.
3.3Grounding
The armouring of metal sheathed cables grounding connection's shall be made by means of screw-type pressure connectors to grounding pads of connections provided on the switchgear in accordance with IEC. All underground connections shall be made by exothermic welding and then encapsulated in epoxy resin, (jointing). A separate protective conductor shall connect the sheath, armouring, ground metal bodies of terminators, splices and hardware according to Manufacturer's written instructions and IEC Codes.
3.4Field Quality Control
A.Upon installation of medium-voltage cables and before circuitry has been energized, demonstrate product capability and compliance, check for physical damage and proper connection in accordance with requirements of code and drawings. Submit qualification of authorized Person to perform specified field quality-control testing for approval.
B.The tests shall be performed to detect wrong connections, short circuits, continuity and grounds.
C.Insulation tests shall be made with a motor driven megger on all cables and conductors. Cables shall be tested phase to phase, and phase to ground, and in accordance with Manufacturer’s instruction and IEC Code.
D.Correct malfunctioning at site where possible and retest to demonstrate compliance, otherwise remove and replace with new units, and retest.
3.5Protection
Provide final protection and maintain conditions, in a manner acceptable to Manufacturer to prevent entrance of moisture into the cable and ensure that medium-voltage cable is without damage or deterioration at substantial completion.
END OF SECTION260513
Technical Specifications for Electrical WorksSection 260513
Revision 0Page 1 of 4Medium Voltage Cables