POWER CABLE INSTALLATION AND TERMINATION
REFERENCES AND INTERNATIONAL STANDARDS FOR POWER CABLE INSTALLATION
M7.12.12 Wire and Cable Specification
IEC 60050 International Electro-Technical Vocabulary
IEC 60055 Paper Insulated Metal Sheath Cables For Rated 1KV to 30KV
IEC 60173 Colours of the Cores of Flexible Cables and Cords
IEC 60183 Guide to the Selection of HV Cables
IEC 60228 Conductor of Insulated Cables
IEC 60287 Calculation of the Continuous Current Rating of Cables
IEC 60331 Fire Resisting Characteristics of Electrical Cables
IEC 60332 Tests on Electrical Cables under Fire Conditions
IEC 60364 Electrical Installation in Buildings
IEC 60446 Colour Identification-Insulated & Non-Insulated Core
IEC 60502 Extruded Sold Dielectric Insulated Power Cables for Voltages from 1KV to 30KV
IEC 60540 Test Methods for the Insulation & Sheaths of Electrical Cables & Cord (Elastometric & Thermoplastic Compounds)
IEC 60754 Tests on Gas Evolved During Combustion of Electric Cables
IEC 60811 Common Tests Methods for Insulating & Sheathing Materials of Electric Cables
IEC 60851 Methods of Test for Winding Wires
IEC 61034 Measurement of Smoke Density of Electric Cables Burning Under Defined Conditions, Test Procedures & Requirement
IEC 61158-2 H1 Field bus cables
PROCEDURE POWER CABLE INSTALLATION
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- Cable installation shall comply with reference codes and design documents.
- All cable drum shall be checked with packing list and confirmed no mechanical damage.
- During cable drum shifting; check mechanical damage, nameplate with cable schedule & drum list and phase rotation of the cable.
- Assure necessary PPE, tools and equipment for cable pulling. Check the latest cable drum list and cable schedule. Prior for cable pulling, QA/QC inspector shall check if all the cable supports are installed and fixed.
- All wire and cable shall be megohm meter tested after it is pulled, but prior to termination.
- High voltage cable shall be given a hi-pot test after it is pulled and stress relief is installed, but prior to termination.
- Electrical cables shall be oil & sunlight resistance and flame retardant shall be used as per IEC 60332.
- Cables used for buried or external installation shall be steel wired armoured. Noted that armouring cables are not required within the building, e.g. from control room to control building rack room
- Cables shall be installed direct buried on the ground or in formed concrete trenches with backfill, fastened to cable ladder rack or tray and in underground ducts.
- Make check for the following during wire and cable installation;
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- The proper type, size, colour and number of wires & cables are being installed.
- For long pulls, the pull is performed as per required pulling tension.
- Cable is not pulled around too many bends.
- Ambient temperature is above the minimum allowed for the cable insulation.
- Proper pulling compound is being used.
- For long pulls, allowable pulling tensions are not exceeded.
- Cables are not bent on too tight a radius.
- Wire and cable is protected and kept clean throughout the pulling operation.
- Cable fill does not exceed NEC requirements.
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- Except for special application for control, power & lighting cables the minimum cross-section shall be 1.5mm². For high voltage, the cross section shall not exceed 185mm² for three core armoured cable and 400mm² for single core cable. For low voltage, the limits shall be 240mm² for a cable whether armoured or not, up to a maximum of three conductors and 400mm² for single core cable.
- Minimum curve radius for cables, where D is the overall diameter, shall be 6xD for un-armoured cables and 8xD for armoured cables.
- Conductors shall be circular, stranded, annealed copper type, class 2 for the cables for fixed installation and class 5 for the flexible cables feeding mobile equipment, as per IEC 60228.
- Junctions/splices, when not removable, shall be made using sleeves, crimped or welded, restoring the integrity of the line by appropriate heat-shrinkable sleeves. Cable splicing shall be prohibited except in case of cable length exceeding the normally manufactured length.
- Cables shall be drummed in maximum continues length, protected against damage during transit and storage. Cable ends shall be sealed and protected.
- Earthing cable conductor shall be stranded annealed copper conductor and tinned in area containing H2S. Insulation shall be PVC, with green/yellow outer sheath.
- Cables used for buried or external installation shall be steel wire armoured. Armouring cables are not required within the building.