KOC-E-008 Rev.2

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KUWAIT OIL COMPANY (KoSoCo)

STANDARDS PUBLICATION

KOC RECOMMENDED PRACTICE FOR THE DESIGN, SELECTION AND INSTALLATION OF ELECTRIC CABLES, CABLE SYSTEMS AND WIRING

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KUWAIT OIL COMPANY (K.S.C.)

KOC RECOMMENDED PRACTICE FOR THE DESIGN, SELECTION AND INSTALLATION OF ELECTRIC CABLES, CABLE SYSTEMS AND WIRING DOC NO: KOC-E-008

ISSUING AUTHORITY:

STANDARDS TEAM

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KOC RECOMMENDED PRACTICE FOR THE DESIGN, SELECTION AND INSTALLATION OF ELECTRIC CABLES, CABLE SYSTEMS AND WIRING DOC. NO. KOC-E-008

Amended CI. 6 . 3

Approved KOC

A. Unnikrishnan

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CONTENTS Page 1.O

SCOPE

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2.0

GENERALIAPPLICATION

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3.0

TERMINOLOGY

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4.0

REFERENCE CODES & STANDARDS

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5.0

ENVIRONMENTAL CONDITIONS

6

6.0

CABLE SYSTEM DESIGN

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6.1 6.2 6.3 6.4 6.5 6.6 7.0

SELECTION OF CABLES 7.1 7.2 7.3

8.O

8.3

7 8 10 11 11 11 11 11 12 16 17

Use of Mineral Insulated Copper-Sheathed Cable (MICS) 17 Flexibility, Oil Resistant and Low Acid and Smoke 17 Emission Requirements Offshore Facilities 17

CABLE INSTALLATION METHODS AND MATERIALS

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Methods of Installation Cable Routing Underground Cable Systems Above Ground Cable Systems Conduit Systems and Trunking Mineral Insulated Copper Sheath (MICS) Cable Cable Grouping and Segregation Cable Jointing and Termination

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9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 10.0

General Approved Cable Types Cable Colour and Core Identification

SPECIAL APPLICATIONS 8.1 8.2

9.0

Voltage Rating of Cables Current Carrying Capacity Voltage Drop Minimum Conductor Size Control Cables Drawings, Schedules and Design Data

SITE TESTING

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General

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10.1 11.0

QUALITY ASSURANCE

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12.0

DOCUMENTATION

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SCOPE

This Recommended Practice describes KOC's guidelines for the design, selection and installation of electric cables, cabling systems and wiring within the company facilities. 2.0

GENERALIAPPLICATION

The design, selection and installation of power cables and wiring shall conform to the requirements of this recommended practice, except as modified or supplemented by the project specification data sheet. 3.0

TERMINOLOGY

Abbreviations KOC BS IEC XLPE PVC SWA EPR CSP LC GSWA SWBA MlCS PlCC 4.0

Kuwait Oil Company (K.S.C.) British Standard International Electrotechnical Commission Explosion proof Cross-linked Polyethylene Polyvinyl Chloride Single Wire Armouring Ethylene Propylene Rubber Chlorosulphonated Polyethylene Lead Covered Galvanised Steel Wire Armour Steel Wire Braided Armouring Mineral Insulated Copper Sheath Paper Insulated Copper Conductors

REFERENCE CODES & STANDARDS

In the event of conflict between this recommended practice and the codes referenced herein, the most stringent requirement shall apply, unless otherwise specified. Any exceptions or deviations from this recommended practice, along with their merits and justifications, shall be brought to the attention of KOC's Controlling DepartmentIStandards Division for their review, consideration and amendment (if required) of the standard. International Standards

IEC 92-3

Part 3: Cables (construction, testing and installations)

IEC 183

Guide to the selection of high-voltage cables

IEC 228

Conductors of insulated cables

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IEC 287

Calculation of the continuous current rating of cables (100% load factor)

IEC 331

Fire resisting characteristics of electrical cables

IEC 332

Tests on electric cables under fire conditions

IEC 502

Extruded solid dielectric insulated power cables for rated voltages from 1 kV to 30 kV

British Standards

BS 5345

Code of Practice for the selection, installation and maintenance of electrical apparatus for use in potentially explosive atmospheres (other than mining applications or explosive processing and manufacture).

BS 5467

Specification for armoured cables with thermosetting insulation for electricity supply rated voltages of up to and including 60011000V & up to and including 1900/3300V

BS 6004

PVC-insulated cables (non-armoured) for electric power and lighting.

BS 6007

Rubber-insulated cables for electric power and lighting.

BS 6207: Part 1

Copper-sheathed cables with copper conductors (MICS)

BS 6231

PVC insulated cables for switchgear and controlgear wiring

BS 6346

PVC-insulated cables for electricity supply

BS 6480

Specification for impregnated paper insulated lead or lead alloy sheathed electric cables of rated voltages up to and including 33kV

BS 6622

Specification for cables with extruded cross linked polyethylene or ethylene propylene rubber insulation for rated voltages from 380016600V up to 19000133000V

BS 6724

Specification for armoured cables for electricity supply having thermosetting insulation and low emission of smoke and corrosive gases when affected by fire. (60011000V & 190013300V ratings)

BS 6883

Specification for elastomer insulated cables for fixed wiring in ships

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BS 6899

Rubber Insulation & Sheath of Electrical Cables

BS 721 1

Thermosetting insulated cables (non armoured) for electric power and lighting with low emission of smoke and corrosive gases when affected by fire (4501750V rating)

BS 7671

Requirements for Electrical Installations: IEE Wiring Regulations 16thEdition.

U.K. Industry Standards

ERA Report 74-29 A method for calculating ratings for cables in multi-layer groups on trays. EEMUA 133

Underground Armoured Cable Protected against Solvent Penetration and Corrosive Attack.

KOC Standards

KOC-E-023 5.0

KOC Standard for Electrical Power Cables and Wiring.

ENVIRONMENTAL CONDITIONS

The environment of Kuwait, is severe on all equipment and must be considered carefully before procurement of plant and equipment. It must be assumed that, unless otherwise specified, equipment may be subjected to sand and fine particle dust storms, sand laden winds, airborne chemical contaminants and extreme temperatures. Humidity can pose a serious problem with long periods of relative humidity levels of 100% being part of the normal weather pattern. Electrical materials shall be designed for continuous operation under ambient temperatures of 50°C in the sun shade. For buried cables a design temperature of 40°C shall be used. Specific attention shall be given to the following environmental factors: (i)

Exposure to seawater or salt spray.

(ii)

Exposure to intense heat radiation from the sun or from a flare.

(iii)

Excessively high or low ambient temperatures.

(iv)

Exposure to oil contamination and water pressure.

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6.0

CABLE SYSTEM DESIGN

6.1

Voltage Rating of Cables

6.1.1

The voltage designation shall be appropriate to the type of system and the earthing arrangements of the supply and shall be selected from the following standard voltage ratings: 6.3511IkV, 1.913.3kV, 0.611kV, 4501750V or 3001500V. N.B.: 4501750V shall be limited to use in office and domestic premises.

6.1.2

The standard voltages employed on site are as follows:

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IIkV 3 phase, 3 wire, neutral low resistance earthed, rated lightning impulse level 75kV peak.

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3.3kV 3 phase, 3 wire neutral solidly earthed, rated lightning impulse level 40kV peak.

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440 V 3 phase, 4 wire, neutral solidly earthed (415V in some remote areas)

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250 V 1 phase, 2 wire, neutral solidly earthed

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110 V

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110V d.c. +_ 10% unearthed

+ 1O h 1 phase, 2 wire, 50Hz

Mains voltage is subject to a variation of The standard frequency is 50 Hz

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0.5Hz neutral solidly earthed UPS

+ 6%

+ 2.5%

The preferred control voltages for circuit breakers and motor starters shall be 110V a.c. or 110V d.c. 6.1.3

Phase Sequence The Company phase sequence is as follows: A - BurganIAhmadilMagwa: Non-standard B - North Kuwait: Standard C - West Kuwait: Standard

(RED-BLUE-YELLOW) (RED-YELLOW-BLUE) (RED-YELLOW-BLUE)

All equipment shall be of standard construction with phases arranged REDYELLOW-BLUE and connected within equipment in the normal phase sequence with RED-YELLOW-BLUE laid out from top to bottom and left to right, when viewed from the front.

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6.2

Current Carrying Capacity

6.2.1

Cables shall be sized to operate within their current carrying capacity as determined by the maximum continuous temperature of the insulation as shown below: MAXIMUM PERMITTED CONDUCTOR TEMPERATURES AND VALUES OF K FOR VARIOUS INSULANTS (COPPER CONDUCTORS)

Note: " K is a constant dependant on the type of conductor, insulation and the initial and final temperatures of the cable. The values of K given in the table assume that the cable is operating at its maximum current carrying capacity. If this is not the true case "K" can be calculated from the following formulae: K = 228.6 X Sq rt of

(243.4 + T,) X In (243.4 + T);

T2 = Final temperature of conductor (C) T I = Initial temperature of conductor (C) In = Actual current in the conductor (A) 6.2.2

In assessing the size of conductor required for a given design current the following factors shall be taken into account: (i) (ii) (iii) (iv)

Ambient temperature. (50°C in air & 40°C buried) Grouping and proximity to other loaded cables Method of installation Thermal conductivity of the medium in which the cable is installed. The value of thermal resistivity for soil to be used for calculation purposes within KOC shall be 2Km/w, ref IEC-287 Appendix A2.2.

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Thermal conductivity of the cable constituents. Depth of buried cables

The required conductor size may be calculated in accordance with the method and formulae given in IEC 287 or, where they are applicable, the tabulated ratings and rating factors given in the following documents may be used: (a) (b) (c)

ERA Report 69-30, Part 1 and Part 3. IEE Wiring Regulations, 16th Edition. IEE Recommendations for the Electrical and Electronic Equipment of Mobile and Fixed Offshore Installations.

6.2.3

Where cables are laid in mixed groups of different types, sizes and loading, the group rating factor of each cable should be calculated or assessed for each cable, taking into consideration the thermal effect of all the other cables of the group. Reference should be made to ERA Report 74-29 or manufacturers recommended grouping factors.

6.2.4

Short-Circuit Rating The short time maximum current carrying capacity shall take into account the currentltime characteristics of the circuit protection device to ensure that cables do not suffer damage due to overheating under maximum through fault conditions. The KOC standard short circuit ratings for electrical equipment are: 33kV IIkV 3.3Kv 440125OV

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1500 MVA 500 MVA 150 MVA 31 MVA

Lower short circuit ratings may be approved or specified for areas with lower fault levels, but they shall not be less than the following: 33kV IIkV 3.3kV

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1000 MVA 250 MVA 75 MVA

Reduced fault levels for the low voltage systems may be considered when provided with adequate electrical protection. 6.2.5

Overcurrent Protection The overcurrent protection characteristics of the circuit protection device shall not exceed the current carrying capacity of the selected cables & system coordination.

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Voltage Drop

6.3.1

Cables shall be sized so that the maximum voltage drop between the supply source and the load when carrying the design current does not exceed that which will ensure safe and efficient operation of the associated apparatus or as follows, whichever is lower:

6.3.2

a)

For high-voltage motors, the voltage drop at the motor terminals shall not exceed 3% at full load current and 15% during starting.

b)

For low-voltage motors, the voltage drop at the motor terminals shall not exceed 5% at full load current and 15% during starting.

c)

The voltage drop on low-voltage Power / Lighting circuits shall be limited to a maximum of 2.5 % unless otherwise specified. The total voltage drop at the farthest light fitting (including branch circuit) shall not exceed 5%.

While carrying out electrical system design, the voltage drop on IIkV feeders shall be kept to the lowest level possible to meet all other design criteria / future additions. The maximum limits specified below have to be used judicially by the designer where transmission of bulk power over a long distance is considered at IIkV, provided all other design criteria could be met: a)

IIkV feeders to GC / BS / Other Facilities: The Voltage drop on 11 kV feeders from Primary (Bulk Power Intake) Substation to Plant Substation (S/S near to GCIBS etc.), fed directly or via Area Substation shall be limited to a maximum of 2%.

b)

IIkV Ring fed system for Oil / Water Wells: Where the bulk power is used for supply to ESPs fed by individual Unit Transformers provided with tap changers to maintain the voltage at required levels, the maximum voltage drop on 11 kV feeders from Primary S/S to 11 kV substation for distribution of ring circuits shall be upto 3% and the total voltage drop at the farthest point of the I l k V ring main feeder shall be upto 5%. Notes: 1)

The above voltage drop limits shall also apply for similar applications where high-voltage feeders of less than IIkV are employed.

2)

For Transmission of Bulk Power over a long distance, voltage above IIkV is being considered by KOC.

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Minimum Conductor Size The minimum conductor sizes for cables shall be as calculated or based on the following whichever is the larger:

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3.3 kV and 11 kV grade cables: 35mm2

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60011000V grade cables: Motors - 4mm2 Power feeders - 4mm2 Lighting and small power, buried - 4mm2 Lighting and small power, above grade -2.5mm2 Control - 2.5mm2

6.5

Control Cables

6.5.1

Control cables shall have a minimum of 20% spare cores over the original design requirements.

6.6

Drawings, Schedules and Design Data

6.6.1

Unless specified otherwise the system designer shall provide the following drawings and schedules: (i) (ii) (iii) (iv) (v) (vi)

Cable routing diagrams. Constructional details of cable tray work and cable tray support systems. Cross sections of cable routes showing the actual arrangement of cables, and separation distances. Interconnection diagrams showing the cable numbers, the core identification numbers and equipment terminal numbers. Cable and cable cutting schedules, providing lengths, destination, construction and size details. Cable gland schedule.

6.6.2

The system designer shall prepare a dossier giving the basis of cable sizing together with specimen calculations. The dossier shall be subject to approval by KOC prior to proceeding to the overall detailed design and shall form part of the permanent records of the site.

7.0

SELECTION OF CABLES

7.1

General

7.1.1

Cables shall have annealed stranded circular or shaped copper or tinned copper conductors and should normally be selected from the types listed below, subject to their being suitable for their operating environment and any special application.

7.1.2

All PVC outer sheaths shall be formed from flame retardant PVC meeting the test requirements set out in IEC 332 Part 3 CAT.A.

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7.1.3

The use of paper insulated cables is subject to KOC approval and should only be considered where they can be justified on a cost basis otherwise XLPE insulated cables are to be selected in preference.

7.1.4

Unarmoured cables can be used if confined to control rooms or other internal areas, provided that mechanical protection is provided by the use of conduit or ducting.

7.1.5

Cables for use in areas classified as hazardous shall incorporate non-hygroscopic fillers in the interstices between the cores. Where a void would otherwise occur at the centre of the cable, this shall also be filled, to make a substantially solid cross section.

7.1.6

Cables laid in the ground shall have an appropriate lead sheath if there is a possibility of the cables coming into contact with hydrocarbon or other organic solvents due to spillage, etc.

7.1.7

Short runs of single core cable may be unarmoured but where armouring is required, it shall consist of aluminium wire or strip.

7.1.8

Installations in control rooms, workshops, offices, substations and accommodation areas shall be carried out using MICS, conduit or trunkinglducting systems.

7.2

Approved Cable Types

A

XLPE Insulated, PVC Inner Sheath. SWA, PVC Outer Sheath Power Cable to IEC 502lBS 6622 (XLPEIPVC shthlSWA1PVC) Voltage grade:

6.3511 1kV

Conductor Screen:

Extruded semi-conductive compound.

Insulation:

Cross linked polyethylene.

Core Identification:

Coloured red, yellow, blue.

Insulation Screen:

Extruded semi-conductive compound, bedding of semi-conductive tape and earth screen of copper tape.

Conductor Lay:

Cores laid up with rubber filling to form a circular cable.

Inner Sheath:

Plastic tape wrapping and bedding of extruded polyvinyl chloride.

Armouring:

Galvanised steel wire.

Outer Sheath:

Extruded polyvinyl chloride.

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XLPE insulated, lead covered, PVC inner sheath, SWA, PVC outer sheath Power Cable to IEC 502lBS 6622 (XLPEILCIPVC shthISWAlPVC1

Voltage grade:

6.3511 1 kV.

Conductor Screen:

Extruded semi-conductive compound.

Insulation:

Cross-linked polyethylene.



Insulation Screen:

Extruded semi-conductive compound, bedding of semi-conductive tape and earth screen of copper tape.

Conductor Lay:

Cores laid up with rubber filling to form a circular cable.

Inner Sheath:

Plastic tape wrapping and lead alloy sheath according to EEMUA 133 or equivalent.

Bedding:


Armouring:

Galvanised steel wires.

Outer Sheath:


Paper Insulated, Lead Covered, Steel Wire or Tape Armour, PVC Outer Sheath Power Cable to BS 6480

Voltage grade:

6.3511 1kV

Conductor Screen:

Semi conductor carbon paper.

Insulation:

Paper tape, mass impregnated non-draining.

Insulation Screen:

Non-ferrous metallic tape.

Core identification:


Inner sheath:

Plastic wrapping with lead alloy sheath according to EEMUA 133, BS 801 or equivalent.

Bedding:


Armouring:

Galvanised steel wires or tape.

Outer Sheath:


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XLPE Insulated, Lead Covered, PVC Inner Sheath, SWA, PVC Outer Sheath Power Cable to IEC 502lBS 5467 (XLPEILCIPVC shthlSWAIPVC1

Voltage grade:

0.611kV or 1.913.3 kV.

Insulation:



Up to four core colours (red, yellow, blue and black). Five cores and above coloured white with black numbers along the length of cores.

Conductor Lay:

Cores laid up with extruded PVC filler for up to five cores. For six cores or more wrapping of polyester tape.

Inner Sheath:


Bedding:


Armouring:

Galvanised steel wire. Single-core cables shall have aluminium wire armouring.

Outer Sheath:


PVC Insulated, Lead Covered, PVC Inner Sheath, SWA, PVC Outer Sheath Power Cable to BS 6346 (PVC/LC/PVC/SWAlPVC~

Voltage grade:

0.611kV or 1.913.3 kV.

Insulation:




Conductor Lay:


Inner Sheath:


Bedding:


Armouring :

Galvanised steel wire. Single-core cables shall have aluminium wire armouring.

Outer Sheath:


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EPR Insulated, CSP Inner Sheath, Steel or Copper Alloy Braid, CSP Outer Sheath Power Cable to BS 6883 or IEC 92-3 for Flexible and Oil Resistant Duties Voltage grade:

0.611kV to 6.35111kV.

Insulation:

Ethylene Propylene Rubber or equivalent type OR1 to BS 6899

Inner Sheath:

Chlorosulphinated polyethylene or equivalent as inner sheath and fillers of synthetic rubber compound type RS3 to BS 6899

Armour:

Galvanised mild steel, tinned annealed copper or tinned bronze braiding.

Outer Sheath:

Chlorosulphinated Polypropylene or equivalent Heat, Oil and Fire retardant synthetic rubber compound to BS 6883 type A, B, C or D selection dependent on requirements.

XLPE Insulated, PVC Inner Sheath, SWA, PVC Outer Sheath Power Cable to IEC 502lBS 5467 (XLPEIPVC shthlSWAIPVC) Voltage grade:

0.611kV or 1.913.3 kV.

Insulation:




Conductor Lay:


Inner Sheath:


Armouring:

Galvanised steel wire. Single-core cables shall have aluminum wire armouring.

Outer Sheath:


PVC Insulated, PVC Inner Sheath, SWA, PVC Outer Sheath Power Cable to BS 6346 (PVCIPVCISWAIPVC) Voltage grade:

0.611kV

Insulation:


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Conductor Lay:


Inner Sheath:


Armouring :

Galvanised steel wire. Single-core cables shall have aluminum wire armouring.

Outer Sheath:


Mineral Insulated Copper Sheathed Cable (MICS) to BS 6207 Part 1 Heavy Duty with Moisture Resistant Insulation.

Voltage grade:

750 V

Insulation:

Compressed powdered mineral, chemically stable and non-corrosive to copper. A moisture resistant insulation version is now available (AEI).

Sheath:

Annealed copper.

Outer Sheath: (When required)


PVC insulated single core cable for use in conduit and Earthing cable to BS 6004,6007 and 6231

Voltage grades:

3001500V, 4501750 V or 60011000V

Insulation:

Extruded polyvinyl chloride (colour to suit service).

Cable Colour and Core Identification

Outer Sheath: Power Cable - Black Earth cable - Yellow and Green Armoured

: Two cores - Red and Black Three cores - Red, Yellow and Blue. Four cores - Red, Yellow, Blue and Black. Five cores and Above: White with black lettering along the core. Earthing cable: Yellow and Green stripes.

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Non armoured: For use in conduit or trunking - colour to suit. Earthing - colour Yellowlgreen. 8.0

SPECIAL APPLICATIONS

8.1

Use of Mineral Insulated Copper-Sheathed Cable (MICS)

8.1.1

Mineral insulated copper-sheathed cable (MICS) should in general be restricted to domestic, commercial and light industrial applications such as in offices, accommodation modules, substations, control rooms and workshops. MICS cable is now available with a moisture resistant insulation making installations less susceptible to humidity. Its inherent fire resistant properties can make MICS suitable for essential circuits as listed in 8.3.3 and high temperature circuits. When exposed to high temperatures under normal operation MICS cable without an external PVC sheath shall be selected.

8.1.2

MICS shall not be used in situations where the equipment to which it is connected is subject to vibration or where the cable may need to be disconnected regularly for maintenance. A loop of cable shall be formed just before the gland where MICS is terminated.

8.2

Flexibility, Oil Resistance and Low Acid and Smoke Emission Requirements

8.2.1

Where flexibility and oil, pressure and heat resistance is required cables shall be selected with synthetic rubber insulation and sheathing from BS 6883 or IEC 92-3. Similar cable is used for submersible pumps but due to the critical nature of these cables they should be obtained from a manufacturer recommended by the pump manufacturer.

8.2.2

A selection of materials providing additional low acid and smoke emission are detailed in BS 6883 Cat C or D. These cables shall be used for trailing and marine circuits.

8.3

Offshore Facilities

8.3.1

Where offshore facilities exists all circuits except "Essential Circuits" shall be flame retardant. A flame retardant cable is constructed totally from materials which will not assist the spread of flame when the cable is exposed to combustion and meets the test requirements set out in IEC 332.

8.3.2

On offshore facilities "Essential Circuits", as listed below, shall be either routed outside Zone 1 hazardous areas or shall be fire resistant. A fire resistant cable is constructed with material which will allow continued normal operation for a period of 3 hours while exposed to a temperature of 750°C in accordance with IEC 331. Additional tests for impact and water resistance to BS 6387 are also required by KOC and are detailed in KOCE023.

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Essential Circuits: ESD Systems. Fire & Gas systems. Essential instrumentation and monitoring circuits. Emergency and "Escape" lighting. Fire pump and alarm circuits. Life saving equipment circuits.

9.0

CABLE INSTALLATION METHODS AND MATERIALS

9.1

Methods of Installation

9.1.1

The following methods of installation may be used provided they are suitable for the type of cable being used: Directly buried. Laid in prefabricated concrete troughs, formed concrete or brick service trenches (with or without sand filling) or ducting. Above ground on trays or ladder racking.

9.1.2

Unless approved otherwise by KOC, the methods given in 9.1.1 should be used as follows: Offsites - Directly buried or on tray and ladder racking. Process Areas - In fabricated trenches or on tray and ladder racking. Inside Buildings and on jetties - Tray or ladder racking.

9.1.3

Concealed Installations Installations in the following areas shall be concealed for aesthetic purposes: Domestic premises Hospital facilities Offices Control rooms

9.1.4

Surface Installations Where aesthetic considerations are not as important as good access, cable installations shall be surface mounted. e.g. Workshops, Utility and Plant rooms, Substations, Pump rooms and A/C rooms.

9.2

Cable Routing

9.2.1

Wherever possible, cables installed above ground shall be routed to avoid the possibility of mechanical damage or areas where leakage andlor spillage of contaminants could occur.

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9.2.2

Installation of essential circuits in offshore environments shall comply with 8.3.2.

9.2.3

Where duplicate feeders or parallel systems are provided for a given duty, e.g. duty and standby pumps, and the cables are installed above ground in a hazardous area, different routes shall be used wherever practical.

9.2.4

The routing of all cables shall be planned concurrently with main pipe racks and vehicle access ways, etc., to provide unimpeded direct routes wherever possible and to make maximum use of overhead pipe tracks and other structures to support cable trays or ladders.

9.3

Underground Cable Systems

9.3.1

Prior to excavation the correct permits to work shall be obtained. In plant areas or within 3 m of other known or suspected cables or pipes excavations shall be carried out by hand.

9.3.2

Completed excavations shall be examined and approved prior to laying of cables.

9.3.3

Cables shall be tested and the results approved before backfilling takes place. Cable ends shall be sealed to prevent ingress until ends are made off.

9.3.4

The first O.lm of backfill shall be sifted sand, well compacted and level. excavated sand and soil may be used for backfill over cable tiles provided Gath and large stones have been removed. The backfill shall be firmly compacted in layers.

9.3.5

Backfill at road crossings shall be maintained at finished road level for up to 5 days by adding backfill. Road reinstatement will be carried out by the company unless otherwise specified.

9.3.6

In unpaved areas, the cables shall be directly buried in excavated trenches. Cables shall be laid on and also covered by 75mm layers of clean sand and then concrete cable tiles 100mm above the cables. The cable covers shall overlap the cables on the extreme outside. The trench shall be backfilled to grade level.

9.3.7

Cable depth to top of grade shall be: Systems up to IkV - 750mm minimum Systems above IkV - 1000 mm minimum

9.3.8

Cables shall be arranged in layers with a minimum of 75 mm of clean sand or riddled soil between each layer. The number and the arrangement of cables shall be approved by KOC prior to installation and the number of layers shall be one unless space is a limitation when the maximum number shall be two.

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Cable trenches inside process plant paved areas shall be filled with sand and closed with a weak cement screed, coloured red, or with reinforced concrete slabs in areas accessible to vehicles. Prefabricated cable troughs shall be closed using prefabricated concrete covers outside buildings and with chequer plate covers inside.

9.3.10

The depth of concrete cable trenches and prefabricated concrete troughs should not normally exceed 750 mm.

9.3.11

All underground cables shall be fitted with indestructible identification bands at each end, at all points where they enter or leave ducts, at all changes of direction and at intervals of not greater than 30 m. The identification shall correspond to that allocated in the cable schedule.

9.3.12

Route markers inscribed in Arabic and English shall be provided to identify all trenches not directly visible at grade. Markers shall, wherever possible, be located directly over the centre line of the trench, or alternatively, suitably marked and located nearby. Inside the Facility where vertical posts would cause interference with pedestrians or traffic, cable markers shall be cast horizontally in concrete at grade level. Markers shall be installed every 30 metres, at changes of direction and where cables enter buildings.

9.3.13

Where cables enter buildings, pass under roads, bunds and similar obstructions they shall be installed in 150mm PVC ducts, sealed in concrete to provide support. At each duct bank, 50% spare ducts shall be provided, with a minimum of 2 (two) spare ducts for future use. All duct ends, including spare ducts, shall be sealed with suitable sealant.

9.3.14

Separate duct sections shall be provided for different Voltage grades when installing cables in ducts by installing multi section ducts. No duct shall have more than 40% of its cross sectional area filled.

9.3.15

Where cables surface from below ground, they shall be protected by substantial galvanised steel pipes which shall extend from 150 mm below ground level to a minimum of 150 mm above ground level to provide mechanical protection for cables. Pipes shall be sized to have 60% of area unused.

9.3.16

Wiring conduit buried in the ground or in trenches will not be permitted.

9.4

Above Ground Cable Systems

9.4.1

Cables shall be protected as required against mechanical damage, chemicals, excessive temperatures and fire by suitable routing and material selection. All cable racks and trays installed in open locations shall be fitted with ventilated sunshades to prevent overheating by direct sunlight. Single cables to pushbutton stations, luminaires, earthing points, etc, may be clipped direct to the mounting surface with suitable fixing devices.

1

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9.4.2

Cable trays shall be heavy duty 2mm thick mild steel hot-dipped galvanised to an approx covering of 610 grmslm2 to BS 729 or similar national standard. For corrosive environments, deep galvanised Corten 'A' steel or Type 316 516 'marine' grade stainless steel are acceptable materials. Subject to KOC approval GRP shall be used where weight saving is an important factor.

9.4.3

The maximum deflection of any cable support system between supports should not exceed 11180 of the span. The traywork system designer shall submit calculations setting out the basis of the design.

9.4.4

Cable trays or ladders shall be capable of supporting an additional point load of 90 kg at the centre of a span without permanent deformation.

9.4.5

Cable trays or ladders shall be bolted or clamped to structural steel supports. They shall not be supported from process piping.

9.4.6

Standard prefabricated bends, tees, reducers and other accessories should be used as required.

9.4.7

Where trays exceed 300mm in width the angle iron frame shall be reinforced by bracing with steel straps at 450mm centres. The protective finish of the additional bracing shall be equal to that of the main supports.

9.4.8

Any holes cut in the cables tray for cable access shall be lead lined.

9.4.9

Cables shall be securely cleated or tied to trays or ladders at intervals of 350mm. On horizontal runs where the cables are supported throughout their length or where a number of small cables are tied together in bunches, these spacings may be increased. Cables shall not be supported or attached to personnel ladders attached to structures.

9.4.10

Single core cables making up 3-phase circuits should be run in 3-phase trefoil groups, securely clamped together to withstand the mechanical force produced by a short-circuit fault. The manufacturer's recommended spacing should be used, although adequate restraint is normally provided by clamps at 1 m spacing on straight runs and 0.5 m spacing on the bends.

9.4.1 1

Cable ties shall be of the following types: (i)

Nylon (1 1 or 12).

(ii)

Polypropylene.

(iii)

PVC coated stainless steel.

Plastic cable ties must not be used in outdoor locations. For MICS, PVC coated copper saddles shall be used.

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EVA or PVC coated stainless steel ties or all-round banding shall be used to provide additional support in Zone 1 hazardous areas at intervals of about 2m. The reusable types of cable tie are preferred. 9.4.12

Above-ground cables shall be fitted with indestructible identification bands at both ends of the cable in accordance with the cable schedule.

9.4.13

Where low voltage cables are laid ion trays they shall not exceed a single layer in depth and shall have 25% spare capacity remaining on each tray. Power cables shall be spaced with gaps not less than the cable diameter, but control cables may be laid together.

9.5

Conduit Systems and Trunking

9.5.1

The use of conduit and trunking shall be limited to electrical services installations in buildings in unclassified areas. This would encompass control rooms, substations, workshops, offices and domestic dwellings.

9.5.2

Installations shall be arranged horizontally or vertically

9.5.3

Trunking shall be of approved types either galvanised painted sheet steel or non-conducting material. They shall be fitted with secure but removable covers at all points of access.

9.5.4

Conduit systems shall be used as extensions to ducting systems.

9.5.5

Conduit systems can be rigid metallic or non-metallic types but all fittings shall be of the same material and the type used must be approved by KOC.

9.5.6

All conduit tees, bends and elbows shall be inspection type where available and shall be located with draw in boxes no greater than lorn apart.

9.5.7

All Conduit and fittings shall have a minimum size of 20 mm, nominal outside diameter.

9.5.8

Metallic conduit shall be hot dipped galvanised steel to BS 4568.

9.5.9

lnstallations within domestic dwellings shall be metallic and concealed for aesthetic purposes at a depth of not less than 25mm from the plaster surface.

9.5.10

Conduits within walls shall be securely fixed and shall require approval before plastering.

9.6

Mineral Insulated Copper Sheath (MICS) Cable

9.6.1

MICS cable shall be installed and terminated by tradesmen who have been trained and are experienced in the use and installation of such cable. they shall use purpose made tools to prevent damage.

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9.6.2

MlCS cable shall not be buried or installed in sand filled trenches. It shall be run inlayers not exceeding two and in no circumstances shall it be bunched.

9.6.3

Bending and setting of the cable shall be neat without any wrinkling on inside radii. Minimum radii of bends and sets shall be in accordance with the manufacturer's requirements.

9.6.4

Through joints shall not be used unless route lengths are in excess of the maximum manufacturers length.

9.6.5

Cable, glands, pot seals, sleeving, tools and other accessories used together must be fully compatible and provided from the same manufacturer.

9.6.6

Glands shall be hexagon type and certified to the hazardous area classification of the installation area. Knurled glands are not acceptable.

9.6.7

Terminations shall be made using cold seal pots which are to be fully engaged and shall not protrude into the equipment as per the manufacturers instructions. Surplus copper swarf and sealant is to be removed before sealing.

9.6.8

The sealing compound is to be fully compressed and the closing disc correctly crimped into position.

9.6.9

Hot seals and special sealing arrangements shall be installed strictly in accordance with the manufacturers recommendations.

9.6.10

The manufacturer's recommendations for excluding moisture from the cable immediately prior to making ends off must be strictly observed.

9.6.11

At terminations conductors are to be insulated with neoprene sleeving or where connections are made into high temperature enclosures silicon rubber or sleeving recommended by the manufacturer shall be used.

9.6.12

Except where positive earth continuity can be correctly maintained earth bonding tails are to be used. These tails must be properly terminated on earth terminals specifically provided for the purpose.

9.6.13

Gland terminations shall be fitted with external plastic shrouds unless the cable duty is for high temperature operation.

9.6.14

Cables in excess of 10 sq mm shall be terminated with compression lugs.

9.7

Cable Grouping and Segregation

9.7.1

High voltage cables shall be laid at least 0.15m from other high voltage cables, 0.3m from low voltage cables and 0.5m from other non-electrical services.

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9.7.2

High voltage cables and Communications cables shall be separated by a minimum of I m and in a multipurpose cable trench a division wall the full depth of the trench shall be provided. For long parallel runs a greater separation may be specified. Where high voltage cables cross telecommunication cables they shall do so as near to a right angle as possible at a minimum distance of 0.5m.

9.7.3

Power cable routes running alongside instrument cable routes shall be separated from them as follows:Power Cables Up to 125V Above 125V and up to 250Vl50A Above 250 V and up to 440Vl200A Above 440V and up to 11kVl800A

Min Distance 250mm 400mm 500mm 750mm

9.7.4

Low voltage cables shall be laid at least 0.15m from telecommunication cables and at least 0.3m from any other service whether in line or crossing.

9.7.5

The horizontal and vertical spacing between adjacent bunches of cable shall not be less than 50 mm.

9.7.6

The minimum road kerb distance from power cables shall be 4m and for telecommunication cables 3m.

9.7.7

There shall be a minimum of 400mm between any cable and the lagging of a steam or hot process line.

9.8

Cable Jointing and Termination

9.8.1

For new installations the use of through joints shall be subject of approval by KOC. The location of all joints should be shown on the appropriate drawings. Joints in cables passing between process and offsite areas should be located in the offsite area. Heat-shrinkable joint kits shall be used for L.T. and H.T. cable (Raychem or KOC approved equivalent).

9.8.2

For existing circuits a maximum of 2 repair joints shall be allowed in In-Plant areas. Joints in cables outside Plant areas such as feeder cables shall be considered case by case and will be subject to KOC approval.

9.8.3

Installation, jointing and termination of high-voltage cables shall be carried out and supervised by specialists able to demonstrate their expertise in this work.

9.8.4

All cable conductors shall be fitted with a correctly sized cable socket or thimble and a means of identification. Cable sockets, thimbles and connectors of the compression type are preferred.

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REV - 2

9.8.5

All cables entering outdoor electrical equipment shall do so via the bottom or side unless the equipment is shielded from the rain or proper sealing arrangements have been incorporated in the glands to prevent ingress. Cable glands shall maintain at least the same degree of protection against ingress of dust and moisture as the equipment enclosure.

9.8.6

Control cables with multi-stranded conductors shall be terminated with pin-ended, crimped ferrules and terminals shall be of the type which clamps the wire or ferrule.

9.8.7

Cables shall be terminated using brass compression glands, incorporating an internal armour clamp and a seal on the outer and inner sheaths, as appropriate. In the interests of standardisation all glands whether for use in zone 1 & 2 hazardous areas shall be Zone 1 certified and suitable for the classification of the equipment it is connected to. All glands shall be fitted with PCP shrouds.

9.8.8

At every HV and main LV feeder, motor cable termination and at each joint a minimum 2m long secured cable loop shall be provided to allow for future reconnections.

9.8.9

Where I l k V multicore cables are connected to overhead lines, heatshrinkable cable termination kits suitable for the environment shall be used. Taking into consideration where core crossing is unavoidable a minimum separation distance of 10mm shall exist between cores.

9.8.10

All cables shall be supported by cable support devices to ensure that no strain is placed on the termination.

9.8.1 1

Each terminal and connected wire or cable core shall be marked and identified with suitable plastic type ferrules, in accordance with the relevant wiring diagram.

10.0

SITE TESTING

10.1

General

10.1. I

All low voltage installations shall be tested in accordance with the requirements of BS 7671 (IEE wiring regulations).

10.1.2

High voltage cables shall be subjected to a voltage test as defined in IEC 502, Clause 18.

10.1.3

Cables connected to switchgear, transformers and motors shall be disconnected prior to dielectric tests. If this is not practicable a reduced test voltage may be used subject to KOC approval.

10.1.4

The Contractor shall provide all test equipment and is responsible for its calibration and accuracy.

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10.1.5

All test results shall comply with the requirements of the project specifications and shall be approved by KOC before any electrical equipment is connected up and energised for use.

10.1.6

All Site test results shall be recorded on test record sheets for each equipment item, circuit or device, each shall be countersigned by KOC.

10.1.7

The format of the test record sheets shall be subject to KOC approval.

11.0

QUALITY ASSURANCE The manufacturer shall operate a quality system to ensure that the requirements of this Standard are achieved. The quality system shall be preferably based on I S 0 9000. Certification may be done by internationally reputed inspection agencies. Verification of a Vendor's quality system is normally part of the pre-qualification procedure, and is therefore not detailed in the core text of this standard.

12.0

DOCUMENTATION All correspondence, drawings, instructions, data sheets, design calculations or any other written information shall be in the English Language. All dimensions, units of measurements, physical constants, etc. shall be in the SI units, unless otherwise specified.

KOC-E-008 Rev.2

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