Scope and General Requirements
This Specification describes the standards, performance, materials, manufacture, supply,installation, testing and commissioning required of an electrical installation carried out in Saudi Arabia.
The intent of the works is to provide for the completion in every detail of the electrical installation unless otherwise stated. This includes (but not limited to) all labor, superintendence, materials, tools, equipment, storage, permits, certificates, drawings,temporary work, inspection,testing, accessories, auxiliaries and incidentals necessary to complete the works in a proper, safe, thorough and skillful manner.
1.2 Particular Specification and Drawings
The electrical installation shall comply in every respect with this specification unless otherwise specified in the Particular Specifications, the Drawings or by written instructions.
1.3 Standards and Regulations
The whole of the installation shall comply with the following statutory obligations and other regulations currently in force:
1. Electricity Ordinance, and other subsidiary legislation made under the Ordinance.
2. Code of Practice for the Electricity (Wiring) Regulations issued by the Electrical & Mechanical Services Department
3. IEC 364 “Electrical Installations of Building”
4. Electricity Supplier Requirements
4.1. The Supply Rules and other requirements issued by the relevant electricity supplier.
5. International Standards
5.1. International Electrotechnical Commission Publications (IEC)
5.2. International Organization for Standardization Publications (ISO)
5.3. European Standards prepares by the European Committee for Electrotechnical Standardization or European Committee for Electrotechnical Commission Publications (EN)
5.4. European Standard adopted as British Standard (BS EN)
6. British Standards, including British Standard Specifications and British Standard Codes
of Practices published by the British Standards institution (BS)
7. Fire Services Department Requirements
7.1. The current requirements of the Fire Services Department, Saudi Arabia, including those specified in the FSD Circulars/Letters and the latest edition of the “Codes of Practice for Minimum Fire Service Installations & Equipment and Inspection & Testing of Installations & Equipment
1.4 Cases of Conflict
In case of conflict between the technical requirements of this specification and other requirements, the following order of preference shall apply:
1. Electricity Ordinance, Chapter 406 and other Subsidiary Legislation.
2. The Particular Specification and/or the contract documents for a particular project.
3. This Specification
4. The relevant Electricity Supplier Requirements
5. Code of Practice for Electricity (Wiring) Regulations
6. IEC 364 “Electrical Installations of Building”
7. Other standards and regulations
1.5 Low Voltage (380/220 V) Equipment
Unless specifically stipulated to the contrary by this specification or the drawings, all equipment shall be designed for continuous operation in an industrial environment under the following conditions:
1. 380/220 V, 60 Hz, TN-S, solidly earthed system
2. Rated insulation voltage 400 V phase to phase, 250 V phase to earth
3. Fault levels as depicted in this specification and/or on the drawings
4. All equipment shall be designed for transient operation in an industrial environment under following conditions:
4.1. Rated impulse withstand voltage 6 kV (1.2/50 S)
Note: in Saudi Arabia the nominal voltage rating of 380/220 is still commonly used. Most equipment procured to the international standards is rated for 400/230. Many countries(including the UK) are migrating their systems to 400/230V. Nominal equipment ratings of either 400/230V or 380/220 shall be deemed suitable for use.
1.6 Environmental Conditions
All equipment and materials shall be rated for the following service conditions:
1. Ambient temperature peak from –5°C to +50°C for 4 hours
2. Ambient average temperature from 0°C to 40°C over 24 hours
3. Altitude up to 2000 M above sea level
4. Relative humidity up to 99% saturation
5. Pollution degree 3 – conductive pollution occurs, or dry, non-conductive pollution occurs which becomes conductive due to condensation.
Notations and symbols used throughout the tender shall comply with the latest edition of IEC 617 “Graphical symbols for electrical power, telecommunications and electronics diagrams”.
All other notations used shall have their normally accepted meaning and where any doubt or ambiguity is found, then the Contractor must seek clarification in writing from the Engineer at the time of tendering.
1.8 Metric Units
The Contractor shall provide all information, manufacturers' data and materials in metric (S.I.)units and dimensions or include a conversion table, which must be printed on or within the data sheets produced by the manufacturers.
1.9 "As-new" Condition
At the time of handover of the whole installation shall be in "as-new" condition. During the course of the installation all equipment shall be protected and shall be restored/repainted as necessary before completion of installation.
Inscription of labels shall be in both English and Arabic. Details shall be submitted prior to engraving.
Labels shall be made on white plastic material with black or red lettering as required.
Lettering shall be engraved on the plastic material. Where the manufacturer fits equipment with labels, these may be used in lieu of the white plastic label provided that they are of the equivalent or better quality.
Labels shall confirm to the following dimensions unless otherwise agreed:
1. 75 mm - for designation of distribution boards, major equipment
2. 15 mm - for sub-circuits, circuit breakers, contactors, etc.
3. 6 mm - selector switches, relays, timers, metering instruments, indicating lights, etc.
1.11 Drawings and Technical Information provided by the contractor
1.11.1 Working Drawings
At the times specified and well before the relevant work proceeds, working drawings shall be prepared and submitted for comment. Working drawings shall be dimensioned, showing construction, sizes, weights, arrangements, operating clearances, performance characteristics and the necessary builder’s work involved.
Working drawings for conduit layout shall clearly indicate the proposed position and size of conduit runs, together with the number of cables, size and circuiting of the cable therein.
1.11.2 As-built Drawings
As-built (or As-fitted) drawings shall show the positions of all conduits, cables, switchgear, distribution boards, Luminaires, lighting protection and earthing and all other items, which have been installed. As-built drawings shall be submitted in the media of prints and computer disks. The contractor shall provide at leas six (6) copies of prints unless otherwise specified.
1.11.3 Size of Drawings
Drawings shall be prepared on the following metric scales:
1. Floor plans and section 1:100
2. Plant room layouts and sections 1:50
3. Details 1:20
Three prints of all as-built drawings together with one plastic negative of each drawing shall be submitted to the Engineer within two months of the date of issue of the certificate of Completion.
1.11.4 Framed Drawings
Upon completion framed drawing for each major switch room showing the schematic
wiring diagrams, tables or charts to indicated the type and composition of circuits,identification and location of item of equipment for that switch room shall be provided.
The framed drawings shall be fixed to the wall in such a way this is can easily be removed for reference.
1.11.5 Drawing Submission
During construction the contractor shall submit a comprehensive “Submission
Schedule” of working drawings, taking into account the overall programme of the installation. No equipment shall be delivered to site and no work shall be executed until such drawings have been agreed. The contractor shall ensure that working drawings are progressively submitted in accordance with the agreed “Submission Schedule:/
Failure to submit working drawings in good time shall not entitle the contractor to an extension of contract period and no claim for extension by reason of such default will be allowed.
As a minimum the contractor shall prove all relevant drawings specified in 19 Deliverable Documentation. The contractor shall provide at least six (6) copies unless otherwise specified.
1.11.6 Technical Information
The contractor shall submit technical literature of all material and equipment to be offered. The literature shall show sufficient details for tender evaluation. Such details shall include construction, dimensions, method of installation, weight, circuit diagrams,material used, etc.
1.12 Operation and Maintenance (O&M) Manuals
Upon completion of the installation the contractor shall submit copies of operating and maintenance manuals incorporating all amendments made during the course of the contact.
The contractor shall provide at least six (6) copies unless otherwise specified.
1.13 Testing & Commissioning Procedure
Prior to and in good time the contractor shall submit a schedule showing the appropriate testing and commission procedure to be carried out. The schedule shall be agreed before any testing and commissioning work is carried out.
A single manufacturer to ensure uniformity of standards and composition shall supply all equipment and equipment/materials of the same type. In the case that it has been shown conclusively that no single manufacturer carries the range of equipment called for, the number of manufacturers shall be limited to a minimum.
All equipment/material delivered to site shall be new and shall be clearly marked to identify different types, sizes and manufacturer.
1.15 Packing, Storage and Protection
All plant, equipment, apparatus, materials and parts shall be delivered to the Site in a new condition, properly packed and protected against damage due to handling, adverse weather or other circumstances, and as far as practicable, they shall be kept in the packing cases or under protective coverings until required for use.
Any items suffering damage in transit or on the Site shall be rejected and replaced without extra cost to the Employer. No item so rejected will be considered as a reason for failure to meet the completion date of the project.
A sample board containing samples of electrical cables, conduits, trunking, plugs and sockets etc., offered by the contactors shall be submitted for approval before commencement of the installation work.
Upon request or where specified, the contractor shall submit samples of any materials, equipment and/or workmanship. Such samples shall be agreed before commencement of the installation work.
Any samples submitted will be retained as examples of the standard of the workmanship or material to be supplied. Any items not complying may be rejected and shall be replaced by the Contractor without any cost.
1.17 Co-Ordination Between Trades
The contractor shall liase with other contractors and tradesmen who will be carrying out other services work on the Site. Prior to the commencement of any work the contractor is to ensure that his work and that of all other trades are coordinated. Where required the contractor shall prepare coordination drawings.
No claims shall be entertained for any costs arising from failure of the contractor to coordinate with other trades.
2. Wiring System, Cables, Conduits, Trunking & Accessories
2.1 Galvanized Steel Conduit, Boxes and Fittings
All conduits and fittings shall comply with the latest edition of the following specifications:
1. IEC 614: Conduits for electrical installations - specification
2. IEC 1035: Specification for conduit fittings for electrical installations
All conduit, boxes and fittings shall be hot dipped galvanized steel unless otherwise specified on the drawings. No conduit shall be of less than 20 mm diameter.
Boxes shall be not less than 2.50 mm thick and not less than 47 mm deep unless otherwise specified. They shall be of such dimensions as will enable the largest size cable, for which the conduit run is suitable, to be drawn in without excessive bending.
All conduit boxes shall be provided with gaskets and lids. Lids shall be of the same gauge as the box and fixed with brass fixing screws. An earthing terminal with brass screw shall be provided in each lighting and power outlet box.
All boxes shall be drilled for holes according to the conduit entries required. All conduit entries to boxes and switchgear shall be made with coupling and hexagon male brass bush with serrated steel washer. Flexible conduit (except for connection to light fittings in suspended ceilings) shall not be used.
All conduit systems shall be supported at interval not exceeding 1.2 m. All bends in conduit runs shall be formed on site in bending machines. Junction box shall be installed wherever tee connections exist.
A telescopic conduit system is to be employed where expansion joints are crossed.
2.2 Cable Trunking
Cable trunking shall be manufactured in minimum lengths of 2m from 1.60mm galvanized sheet steel finished with rust resisting primer and sprayed overall with enamel paint.
Covers shall be of the quick-fix pattern with centre captive screw of spring-on type. Fixing arrangement employing self-tapping screws shall not be accepted.
2.3 Cable Trays
Cable tray shall be perforated, 2mm, thick mild steel, galvanized finished and with return edges.
Tray supports shall be spaced according to the number and size of cables being carried on the tray, but nowhere shall they exceed 1.5m intervals to ensure that tray sag does not exceed 1:500 with all cables.
2.4 Cable Ladder
The cable ladder system shall be O-line type OL76 or an agreed equal.
The complete cable ladder system shall be purchased from a single manufacturer. The cable ladder manufacturer shall prefabricate all components, including ladder sections, bends, tees,reducers, splicers and covers.
Site fabrication or modification of cable ladder sections is not allowed. Only in exception circumstances and with written approval will site fabrication or modification of cable ladder components be allowed.
The complete support system and the cable ladder shall be capable of carrying twice the actual weight of all equipment, cables and supporting system. Calculations shall be submitted for approval on the adequacy of the support system.
Cable ladder shall be manufactured from mild steel and hot-dip galvanized.
Cable ladder shall be supported from the structural slabs by mild steel U-channels and hangers. Supports shall be provided at intervals not exceeding 1000 mm and at 225 mm from bends and tee-offs.
Covers shall be installed on all cable ladder run outdoors.
3 Power Cables
All cables shall be manufactured to the appropriate latest edition of the following standards:
3. IEC 227 “Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V”
4. IEC 502 “Extrude solid dielectric insulated power cables for rated voltage form 1kV up to 30 kV”
5. IEC 245 “Rubber insulated cables of rated voltages up to and including 450/750”
6. IEC 189 “Low frequency cables wand wires with PVC insulation and PVC sheath”
7. IEC 702 “Mineral insulated cable and their terminations with a rated voltage not exceeding 750V”
8. IEC 55 “Paper insulated metal sheathed cables for rated voltages up to 10/30 kV”
9. IEC 228 “Conductors for insulated cables”
10. IEC 331 “Fire resisting characteristics of electric cable”
11. BS 7211 “Specification for thermosetting insulated cables (non-armoured) for electric power and lighting with low emission of smoke and corrosive gases when affected by fire”
12. BS 6724 “Specification for armoured cables for electricity supply having thermosetting insulation with low emission of smoke and corrosive gases when affected by fire”
BS 6387 “Specification for performance requirements of cable required to maintain circuit integrity under fire conditions”
The current carrying capacity of all cables and wires shall be in accordance with the latest edition of the following specifications:
1. IEC 364: Electrical installation of buildings
All cables and wires shall be sized to limit the voltage drop at the equipment to less then 5% and conform to the following minimum dimensions:
1. 1.5 mm² for bell and control circuits
2. 2.5 mm² for general lighting, power and distribution circuits
3. 2.5 mm² for small power ring final circuits
4. 2.5 mm² for earth conductors
The armour shall be of galvanized steel single wire for multi-core cables. Single core cables shall be provided with non-ferrous sheath and shall be without steel armour.
All cables for lighting and small power wires shall be run in trunking and conduit unless otherwise specified on the drawings. All other cables shall be run on cable ladder unless otherwise specified on the drawings.
The minimum bending radius shall be not less than that recommended by the manufacturer.
Cables installed horizontally shall be cleated at intervals of not exceeding 2 m. Cables are installed vertically shall be cleated at intervals not exceeding 1 M.
Unless agreed in writing joints in cables and wires shall not be allowed.
4 Low Voltage Switchgear & Associated Equipment
Low voltage switchgear and associated equipment shall be assembled, installed and tested in accordance with the latest edition of the following specifications:
1. IEC 364: Electrical installations of buildings
2. IEC 947: Low-voltage switchgear and control gear.
3. IEC 439: Low-voltage switchgear and control gear assemblies.
4.2 Short Circuit Rating and Continuous Current Rating
All low voltage switchgear shall be suitably rated for the specified prospective short-circuit current which can occur at the point of its installation. It should also be rated for uninterrupted duty when carrying continuously the specified full load current.
In the event that short circuit ratings cannot be obtained, low voltage switchboards shall be rated for fault conditions equivalent to 31 MVA at 415V for three seconds.
4.3 Degree of Protection for Enclosure
Enclosures for low voltage switchgear and associated equipment shall be of the totally enclosed type.
For indoor applications, the enclosure shall have a minimum IP rating of at least IP41 for the top surface and IP31 for the other surfaces. For outdoor applications, the enclosure shall have a minimum rating of at least IP 54. Ratings should be greater is specified on the drawings or specifications.
All IP ratings shall conform to IEC 529 “Degrees of protection provided by enclosures (IP Code)”.
As far as possible, all items and equipment contained within the switchboards shall be the products of a single manufacturer. In the case that it has been shown conclusively that no single manufacturer carries the range of equipment called for, the number of manufacturers shall be limited to a minimum.
4.5 L.V. Switchboards
All low voltage switchboards shall be stationary, form 4, cubicle-type assemblies, suitable for indoor operation complete with separate.
Arrangements of low voltage switchboards showing all wiring, busbars, circuit breaker arrangements, glanding/cable entry arrangement, neutral bars, earth bars, and enclosure assembly details shall be agreed prior to purchase/manufacture.
The L.V. switchboards shall be type tested and type test certificates issued by an independent and agreed test authority shall be submitted.
Front access doors shall be provided and the back of the panels shall be removable.
Removable gland plates shall be provided at the top and at the bottom of the switchboard. All doors shall have concealed hinges and be interlocked with the switch mechanism. A means of overriding this interlock by competent persons shall be provided.
All paint finishes shall be of high quality enamel. A minimum of two undercoats shall be applied and each built-up and flattened separately. The final coat shall be of an agreed light colour gloss finish. If the manufactures standard paint finish can be shown to be equivalent or
better, this may be used subject to approval.
All terminals shall be shrouded, and those terminals that remain live with switchboard isolated shall be adequately labelled with cautionary signs. All control circuits shall be provided with removable links/MCCBs/Fuses to facilitate isolation, checking and maintenance.
All control/internal wiring shall be PVC insulated, a minimum size of 1.5 mm2, neatly run on supporting cleats and terminated on the "Klippon" type terminal blocks. Loops shall be incorporate to permit the opening of doors and removal of components for inspection without disconnecting the cables.
An agreed wire colour and marking system shall be used. All wire terminating onto circuit breakers, contactors, relays, timers, etc. shall be labelled.
4.6 Distribution Boards & MCB Boards
Distribution boards shall be provided to serve process equipment, mechanical equipment,lighting circuits and small power outlets as specified on the Drawings.
Arrangements of distribution boards showing all wiring, busbars, circuit breaker arrangements,glanding/cable entry arrangement, neutral bars, earth bars, and enclosure assembly details shall be agreed prior to purchase/manufacture.
Enclosure doors shall be fitted with latched closing device. The sheet metal for the board shall be not less than 1.60mm and for the door shall not be less than 2mm thick.
Reference to 'A', ' B’ and 'C' in this specification or any drawings shall be taken to mean and be identical with the designations 'R', 'Y' and 'B' phase.
Inside each distribution board door, a circuit record card, enclosed in a Perspex envelope shall be provided and fixed to the door. This shall give the total number of circuits, circuit breaker rating for each circuit and a description of what each circuit supplies.
An agreed wire marking system shall label all wires terminating onto circuit breakers. The markings shall identify the cable number, equipment number being supplied and/or circuit number.
All final circuits not connected to a fixed load (i.e. 32A ring final circuits, 32A radial final circuits,etc.) shall be supplied by and MCB with integrated RCD protection. Each separate circuit shall have independent RCD protection. The use of one RCD to protect more than one final circuit is not acceptable.
4.7 Fused Switchgear
Fused switchgear and switches shall be suitable for surface mounting, with enclosures fabricated form sheet steel.
All doors shall have concealed hinges and be interlocked with the switch mechanism. A means of overriding this interlock by competent persons shall be provided.
Fused switchgear shall utilise cartridge fuses to IEC 269 “Low-voltage fuses”. All neutrals shall be taken through taken through a bolted link.
4.8 Motor Control Centres (MCC)
Motor control centres shall conform to the requirements of section 4.5 L.V. Switchboards.
Each motor control circuit shall incorporate a motor protection circuit breaker, suitably rated contactors, suitably rated overload devices, and the necessary relays to achieve the desired functionality. All external connections shall be brought out the terminal blocks.
The type of motor control circuit (direct on-line, variable speed drive, star-delta, etc.) shall be as shown on the drawings.
Unless otherwise indicated, the functioning of each motor control circuit shall be as follows:
4. ‘Start’ and ‘Stop’ buttons located locally on the motor control centre compartment and remotely at the motor shall control each motor. A local remote selector switch shall be provided on the motor control centre.
5. An emergency stop button (of the latching, mushroom head type) shall be installed within 2 m of the motor. This may be incorporated into a stop/start station and function as the stop button as well.
6. Lamps located on motor control centre compartment door shall provide positive indication of motor running and motor stopped. A current sensing device shall drive the motor running indication.
7. A lamp located on the motor control centre compartment door shall provide motor fault indication (circuit breaker trip, overload trip, etc.)
8. A lamp located on the motor control centre compartment door shall provide positive indication of power applied to that motor control centre circuit.
9. A test button shall be provided on the motor control centre which when held down will light all lamps for testing purpose
4.9 Spare Ways
Low voltage switchboards, distribution boards, fused switchgear and motor control centres shall be provided with spare ways for future expansion. For new installations, the number of spare ways shall not be less than 20% of the total number of outgoing ways. Each spare way shall be blanked off with a suitable banking plate.
4.10 Air Circuit Breaker (ACB)
Air circuit breakers shall be provided as shown on the Drawings.
Unless otherwise specified, air circuit breakers shall have built-in overload protections with IDMT characteristics and instantaneous short circuit interruption.
Air circuit breakers shall have the following performance characteristics:
1. Rated short-circuit breaking capacity of not less than 50 kA
2. Rated short-circuit making capacity of not less than 105 kA
3. Rated short-time withstanding current of not less then 50 kA for 1 second
The enclosure shall be fitted with a set of racking gear which shall lock the air circuit breaker in threes distinct positions:
1. CONNECTED – the air circuit breaker can only be fully closed in this position.
2. TEST – it shall be possible to operate the air circuit breaker to close and test the secondary and auxiliary contacts (but not the main isolating contacts).
3. ISOLATED – the air circuit breaker is complete isolated.
A local push button shall be provided for manual tripping. Remote operations shall be provided as shown on the Drawings.
The operating mechanism shall be trip-free.
Mechanical interlocks shall be provided to cater for the following functions:
1. The circuit breaker cannot be inserted or withdrawn when in the closed position.
2. The circuit breaker cannot be closed until it is fully engaged in either the CONNECTED or TEST position.
3. The circuit breaker cannot be slowly closed except in the TEST or ISOLATED position
4. It shall not be possible to initiate the closing action of the energy stored spring mechanism until the spring has been fully charged.
4.11 Moulded Case Circuit Breakers (MCCB)
Moulded-case circuit breakers shall be fixed or plug-in/withdrawable. For plug-in/withdrawable versions, a safety trip shall provide advanced opening to prevent connection and disconnection of a closed circuit breaker
All poles shall operate simultaneously for circuit breaker opening, closing and tripping. Neutral switching shall not be allowed, unless specifically indicated on the drawings.
The moulded-case circuit breakers shall be actuated by a toggle or handle that clearly shows the three positions: ON, OFF and TRIPPED. The operating mechanism shall be designed such that the toggle or handle can only be in OFF position when the power contacts are all actually separated.
Moulded-case circuit breakers shall be able to receive a device for locking in the OFF position,with up to 3 padlocks.
Triple pole circuit breakers shall be interlocked internally so that an overload on any one phase shall trip all three phases of the breaker simultaneously.
4.12 Miniature Circuit Breakers (MCB's)
Miniature circuit breakers used in the distribution boards shall be type 3 and shall be DIN rail mounted type.
Each miniature circuit breaker shall have integral overload protection and short circuit protection. Integral residual leakage protection shall be included where specified on the drawings.
Terminals shall be of the tunnel or cage type (IP20) fully enclosing the cable. Terminations formed by placing the cable underneath a screw head and pinching it, are deemed not to comply with this specification.
The operating mechanism shall be mechanically free from the operating handle to prevent the contacts from being held closed against short circuit and overload conditions.
The operating handle shall be of the toggle type with possibility to padlock in the "ON" or "OFF" position.
The operating toggle shall be capable of assuming 2 positions only, either "ON" or "OFF", the tripped position being the same as "OFF". The "OFF" or "ON" position shall be directly engraved on the toggle itself or printed on the front face.
Miniature circuit breakers shall be single pole or three pole only. Neutral switching is not allowed.
Single pole miniature circuit breakers shall be used for sub-circuit control and protection on all lighting and small power circuits. Three pole breakers shall be used for three-phase equipment. All miniature circuit breakers feeding small power outlets shall contain integrated RCD protection.
4.13 On-Load Isolators
On-load isolators shall comply with the latest edition of the edition of the following specifications:
1. IEC 947: Low-voltage switchgear and control gear.
On-load isolators shall be surface mounted and have a minimum protection rating of IP3X unless otherwise shown on the drawings. The operating handle shall be of the rotary type with possibility to padlock in the "ON" or "OFF" position.
The "OFF" or "ON" position shall be directly engraved on the handle itself or printed on the front face.
On-load isolators shall be single pole or three pole only. Neutral switching is not allowed unless specifically indicated in this specification or on the drawings.
Isolators shall be provided for all mechanical and process equipment as detailed on the load list (excluding lighting and small power socket outlets). The rating of the isolator shall be equal to the rating of the supply circuit breaker in the distribution board.
Isolators shall be positioned within 2 m of the equipments, with the position to be agreed on site prior to installation.
Cabling is to be run and terminated into each isolator. Cabling from isolators to the mechanical and process equipment supplied by others will be by others. Cabling from isolators to equipment supplied as part of these works forms part of the scope of the electrical installation work.
Busbars installed in switchboards shall be so arranged that all conductors can be brought onto the bars without undue bending. Busbars shall be coloured at intervals not exceeding 600 mm for phase identification.
Full size neutral bars shall be provided.
4.15 Automatic Changeover Contactors (Mains Failure)
The automatic changeover contactors shall be 4-pole and rated for AC-3 duty. The automatic changeover contactors shall consist of the following basic elements:
1. Main contacts to connect and disconnect the load to and from the sources of power.
2. Sensing/Supervisory circuits to constantly monitor the condition of power sources and thus provide the signal necessary for the contactors and related circuit operation.
3. Transfer mechanism to effect changeover of the main contacts from source to source.
4. Status indication to show which source of power the load is connected.
Failure of one or more phases of the incoming supply, or a reduction in voltage to less than 60% of normal, shall initiate an adjustable timing device (0 to 15 seconds). If the failure persists the automatic changeover device shall switch to the auxiliary supply.
After restoration of the normal supply, the automatic changeover switch shall automatically be restored to its normal position after a present period of ten seconds.
Automatic transfer control shall be incorporated into the low voltage distribution/switchboard as detailed on the drawings. The automatic changeover contactors shall be electrically and mechanically interlocked to ensure that the two sources of supply will not be parallel.
On site testing shall include, the following:
1. Appropriate tests specified in section 16 Testing.
2. Mechanical tests including checking of all mechanical and electrical connections,interlocks, etc.
3. High voltage injection test.
4. Functional checks of all control circuits.
5. Calibration of metering instruments, current transformers, etc.
6. Primary injection tests.
7. Secondary injection tests.
8. Any other tests as recommended by manufacturer.
9. Any other tests as specified by the engineer.
5 Medium Voltage (MV) Switchboards
Medium voltage switchboards shall be constructed, installed and tested in accordance with the latest edition of the following specifications:
1. IEC 298: A.C. metal-enclosed switchgear and control gear for rated voltages above 1 kV and up to and including 52 kV
2. IEC 56: High-voltage alternating-current circuit-breakers
1. IEC 364: Electrical installations of buildings
2. IEC 947: Low-voltage switchgear and control gear.
3. IEC 439: Low-voltage switchgear and control gear assemblies.
The installation and testing of the medium voltage switchboards shall fully comply with any regulations and requirements of the local power supply authority.
An agreed international switchboard manufacturer shall manufacture all medium voltage switchboards.
Medium voltage switchboards shall be rated as detailed on the drawings. Medium voltage switchboards shall include all instruments, transformers, protection relays and devices as indicated on the drawings.
All medium voltage switchboards shall be stationary, suitable for indoor and have a minimum enclosure rating of IP31. The enclosure rating shall conform to IEC 529 “Degrees of protection provided by enclosures (IP Code)”.
All doors shall have concealed hinges and be interlocked with the switch mechanism.
Schematic diagrams showing all components, terminals, terminal numbers, wiring and wire numbers shall be agreed prior to purchase /manufacture.
General arrangements showing all wiring, busbars, circuit breaker arrangements,glanding/cable entry arrangement, neutral bars, earth bars, and enclosure assembly details shall be agreed prior to purchase/manufacture.
5.3 Remote operation and mimic panel
A wall-mounted panel shall be provided to enable remote operation of the medium voltage switchgear and mimic the status of the circuit breakers.
Remote operation shall allow the circuit breakers opened and closed by means of a rotary switch. Mimic of the circuit breakers shall fully indicate the actual position (open, closed,tripped, test, etc).
The remote operation and mimic panel shall contain a single line representation of the medium voltage switchboard.
Key lock facilities shall be provided for operating personnel to enable/disable the remote operation capabilities. Even with remote operation disabled, the current status of the circuit breakers shall be accurately represented.
6 Busbar Trunking System
Busbar trunking systems shall comply with the latest edition of the following specifications:
1. IEC 439 “Low-voltage switchgear and control gear assemblies”
2. BS 1432 “Specification of copper for electrical purposes: high conductive copper rectangular conductor with drawn or rolled edges”
3. BS 1433 “Specification for copper of r electrical purposes. Rod and bar”
4. IEC 529 “Degrees of protection provided by enclosures (IP Code)”
The busbar trunking system shall be of the totally enclosed type with ingress of protection not less than IP54 for indoor erection and IP66 for outdoor erection. It shall be constructed to withstand heavy mechanical loads as stated in IEC 439.
Adjacent lengths of busbar shall be butt-joined and the joint shall be mechanical and electrically continuous. The mechanical strength of the joint shall not be less than that of the busbar casing.
The busbars shall be insulated form the casing to maintain a clearance and creep age distance as specified din Clause 18.104.22.168 of IEC 439-1. The insulation material shall be of heat resistant, self-extinguishing, non-hygroscopic, high electrical ad mechanical strength to withstand the stress under normal and short circuit conditions.
The casing shall be finished in enamel paint to a grey colour unless otherwise specified.
Busbars shall be three phase and full rated neutral made of hard drawn, high conductivity solid copper bars.
The busbar including all electrical contact surfaces shall be silver or tine plated. The busbars shall be of adequate size to carry the rated current continuously at an ambient temperature of 40°C without exceeding the temperature rise in accordance with Clause 7.3 or IEC 429-1.
Each bar shall be painted to indicate the phase to which it is connected. Painting shall comprise of a band of colour at each accessible position of the busbars.
6.4 Feeder units
Feeder units shall be of manufacturer’s proprietary produce. The rated current and rated short time withstand current shall not be less than that of the busbar trunking system to which it is connected.
6.5 Tap-Off Units
Tap-off units shall be used for branch circuits. Moulded case circuits breakers or fuses of the appropriate current ratings and short circuit breaking capacity shall be provided as near as practically possible to the tapping position for protection of the branch circuits.
Plug-in tap off units shall be attached on the busbar casing and held in position by means of a quick fastening/release device.
Tap-off units shall make positive earth connection and shall be equipped with internal barriers to prevent direct contact. Mechanical interlocks shall be incorporate such that the tap-off unit cannot be inserted or removed form the busbar trunking unless it is in the switched OFF position.
6.6 Busbar Expansion Unit
Any busbar expansion unit shall be of a single pole laminated copper strip designed to appropriate current ratings and shall be arrange to take up the axial expansion or contraction of the busbar system under normal service conditions.
6.7 Fire Barrier
Fire barriers shall be made of non-hygroscopic material having a fire resistance period of not less than the corresponding compartmentation wall or slab where it is installed. A factory fabricated internal barrier shall be used.
Bends, tees and intersection units shall be specifically designed and manufactured for the particular type of busbar systems with which it is to be used. The casing shall be of the same material and finish as the busbar casing and shall have a cross-sectional are not less than that of the busbar casing.
6.9 Short time withstand rating
Short circuit tests on the phase and neutral busbars shall be carried out to the levels specified.
In the event of levels not being specified, test shall be carried out to:
1. Busbar rating < 500 A 40 kA minimum for 1 second
2. Busbar rating 500 to 1600 A 40 kA minimum for 1 second
3. Busbar rating > 1600 A 100 kA for three seconds
Luminaires shall be constructed, installed and tested in accordance with the appropriate latest edition of the following specifications:
1. IEC 598 “Luminaires”
2. IEC 920 “Ballasts for tubular fluorescent lamps. General and safety requirements”
3. IEC 921 “Ballasts for tubular fluorescent lamps. Performance requirements”
4. IEC 928 “AC supplied electronic ballasts for tubular fluorescent lamps. General and safety requirements”
5. IEC 929 “AC supplied electronic ballasts for tubular fluorescent lamps. Performance requirements”
6. IEC 1048 “Capacitors for use in tubular fluorescent and other discharge lamp circuits. General and safety requirements”
7. IEC 1049 “Capacitors for use in tubular fluorescent and other discharge lamp circuits. Performance requirements”
8. IEC 155 “Starters for tubular fluorescent lamps”
9. IEC 926 “Starters devices (other than glow starters). General and safety requirements”
10. IEC 927 “Starters devices (other than glow starters). Performance requirements”
11. IEC 400 “Lamp holders for tubular fluorescent lamps and starter holders”
12. IEC 81 “Tubular fluorescent lamps”
13. IEC 901 “Compact fluorescent lamps”
14. IEC 245
Luminaires excluding the fluorescent lamp shall be supplied as a complete set comprising control gear, lamp holders, cable terminal, block, etc., interconnected with cable of appropriate colour codes. The lamp circuit operating power factor shall not be less than 0.85.
Low loss ballast or electronic ballast shall be used. The low loss ballast shall not give wattage loses exceeding:
1. 6 watts for 18 and 36 watt units
2. 8 watts for 58 watt units
The noise generated by the ballast shall not exceed 24 dB(A) when measured in a noiseless room. Harmonicas generated by the ballast shall be within the limits set by IEC 555 “Disturbances in supply systems caused by household appliances and similar electrical equipment”.
7.3 Fluorescent Tube
Fluorescent tubes shall have (but not limited to) the following:
1. Colour rendering property (Ra) with values not less than
1.1. 50 for car parking spaces and similar
1.2. 80 for office areas or similar
1.3. 90 for hospitals or other clinical areas
2. Energy saving
3. Compatible to type of lamp circuit
Luminaires shall be adequately supported in accordance with manufacturer's
recommendations. All luminaires shall be suspended independently unless otherwise agreed.
8 Miscellaneous Wiring Accessories
All wiring accessories shall comply with the latest edition of the following specifications:
1. IEC 670 “General requirements for enclosures for accessories for household and similar fixed electrical installations”
8.2 Lighting Switches
Lighting switches shall be single pole and rated as specified in the Particular Specification or drawings.
Switches in plant rooms and switch rooms, etc., shall be mounted in surface mounting boxes.
Switches in all other areas shall be flush mounted, all insulated, single pole and white in colour.
Multi-gang switch units shall not switch more than one phase and shall be built up on the grid switch system.
Lighting switches shall be mounted 1350mm above floor level unless otherwise specified.
8.3 Socket Outlets
Socket outlets and plugs rated at 2A, 5A or 15A for general application shall comply with BS 546 “Specification for two pole and earthing pin plugs, socket outlets and socket outlet adapters. Socket outlets and plugs rated at 13A shall comply with BS 1363 “Specification for
13A fused plugs and switched and un-switched socket outlets”.
For socket outlets in the plant rooms, boxes shall be of surface mounting cast iron type.
In lift pit areas, socket outlets shall be of the weatherproof socket outlets shall comply with IEC 309 “Plugs, socket outlets and couplers for industrial purposes”. A screw cap with chain attachment shall be provided for the socket when it is not in use.
In all other areas, socket outlets shall be flush mounted, all insulated and white in colour.
8.4 Fused Connection Units
Fused spur units for the control of single phase supplies to fixed equipment shall be provided with separate outlet box allowing final connection as specified on the Drawings.
Fused spur units shall have earthing facilities for connection to the metalwork of appliances being supplied.
8.5 Indicating Control Switches
Indicating switches shall be 20A, double pole, flush mounted, all insulated, white colour, with neon pilot lamps. Proper words shall be engraved on the cover plate to designate the equipment served. Mounting height shall be 1 350mm above finish floor level, unless otherwise specified.
8.6 Water Heater Connection
Final connection to electric water heaters shall be made via terminal block with moulded cover plate. The terminal blocks shall be adequately rated. The power supply to the water heaters shall be controlled by triple pole switches located outside and immediately adjacent to the bathroom doors as shown on the Drawings.
8.7 Bell Push and Door Bell
Bell pushes shall be flush mounting types with white coloured front plates.
Bell transformers shall be air-cooled double wound with one side of the secondary low voltage winding earthed. Door chime and bell transformer shall be housed in the same enclosure which shall be mounted as shown on the Drawings.
8.8 Telephone Outlet
At each telephone point, an IEC 670 conduit box of 35 mm deep with a moulded blank plate shall be provided unless otherwise specified. Unless otherwise specified, outlet boxes shall be box flush and white in colour.
8.9 Data Outlet (Computer Outlet)
At each data point, an IEC 670 conduit box of 35 mm deep with a moulded blank plate shall be provided unless otherwise specified. Unless otherwise specified, outlet boxes shall be box flush and white in colour.
8.10 FM/TV Outlet Box
At each FM/TV point, an IEC 670 conduit box of 47 mm deep with a moulded blank plate shall be provided unless otherwise specified. Unless otherwise specified, outlet boxes shall be box flush and white in colour.
8.11 Inter-Communication and PA system
At each inter-communication point, an IEC 670 conduit box of 35 mm deep with a moulded blank plate shall be provided unless otherwise specified. Unless otherwise specified, outlet boxes shall be box flush and white in colour.
8.12 Shaver Socket
Shaver socket shall comply with EN 60742 “Isolating transformers” and shall be all insulated,suitable for both flush and surface mounting. Shaver socket shall be white unless other wise specified.
Each outlet shall comprise two outlets; one for 110V and the other for 220V, obtained for the tapping of a double wound transformer and with unearthed secondary windings.
9 Measuring Instruments & Other Devices
9.1 Current Transformers
Current transformers for electrical measuring instruments and protective devices shall be assembled, installed and tested in accordance with the latest edition of the following specifications:
1. IEC 185: Current transformers
Power ratings, current ratios, frequency and class shall be as indicated on the drawings and/or detailed in this specification.
Current transformers shall be rated as:
1. 5P10 - general protection
2. class 'X' - differential protection
3. class 0.1 - measuring
9.2 Voltage Transformers
Voltage transformers for electrical measuring instruments and protective devices shall be assembled, installed and tested in accordance with the latest edition of the following specifications:
1. IEC 186: Voltage transformers
Power ratings, voltage ratios, frequency and numbers of phases shall be as indicated on the drawings and/or detailed in this specification.
9.3 Protection Relays
Protective relays, devices and instruments shall be assembled, installed and tested in accordance with the latest edition of the following specifications:
1. IEC 255: Electrical Relays
2. IEC 51: Direct acting indicating analogue electrical-measuring instruments and their accessories
3. 5IEC 485: Digital electronic dc voltmeters and dc electronic analogue-to-digital converters. All protective relays shall be of the 'static' type. Electromechanical relays shall not be used.
9.4 Indicating Instruments
Indicating instruments shall comply with the latest edition of the following specifications:
1. IEC 51: Direct acting indicating analogue electrical-measuring instruments and their accessories
2. IEC 485: Digital electronic d.c. voltmeters and d.c. electronic analogue-to-digital converters.
Indicating instruments shall have the following ranges, unless otherwise indicated on the drawings:
1. Voltmeters: 0 - 250 V, phase and 0 - 400 V line to line
2. Ammeters: Suitable for the current range to be measured
3. Frequency: 0 - 60 Hz
9.5 Ammeter Selector Switch
Ammeter selector switches where specified shall be mounted on the front of the panel and shall be of the rotary type with make-before-break contacts for selection to read red-yellow-blue-neutral currents with R-Y-B-N marked clearly on the switch.
9.6 Voltmeter Selector Switch
Voltmeter selector switches where specified shall be mounted on the front of the panel and shall be of the rotary type with break-before-make contacts for selection to measure red-yellow, yellow-blue, blue-red and red, yellow and blue phase voltages with RY, YB, BR, R-Y-B marked clearly on the switch.
9.7 Control and Auxiliary Relays
Control and auxiliary relays shall be plug-in type, rack-mounted, provided with cable connection sockets and anchored by quick fastening vibration-proof devices.
All contacts shall be double breaking type. Relay coils shall be rated at 250V single phase A.C. supply, and they shall operate when the voltage is reduced to 85% of nominal. Drop out voltage shall not occur at voltages exceeding 65% of nominal.
Contact elements and operating coils shall be replaceable and be enclosed in transparent dust-proof plastic case or available for easy inspection.
Each relay shall have a minimum of one pair of normally open and one pair of normally closed spare contacts.
10 Earthing & Lightning Protection System
Earthing and lightning protection design shall be carried out in accordance with the latest edition of the following specifications:
1. IEC 364: Electrical installation of buildings
2. Code of Practice for the Electricity (Wiring) Regulations
3. IEC 1024: Protection of structures against lightning
All aspects of the installation shall comply with the electricity supplier’s requirements.
10.2 Power System Earth
The earthing system shall consist of earth electrodes and earth continuity conductors, etc., for providing safety earth to the electrical system. The power system earth will also provide a return path for fault currents and the appropriate protection systems.
All metalwork associated with the electrical installation not forming part of a phase or neutral circuit shall be bonded together, and shall be solidly and effectively earthed.
Joints in and connections to the earthing systems shall be so effected as to avoid undue reduction of the current-carrying capacity of the earth bar. Special precautions shall be taken to ensure that the available contact area is fully utilized in all connections to plant and apparatus.
Power system earth tapes shall be copper tapes with 25 x 3mm cross-section. The contact faces of earth terminals shall be cleaned before connections are made to the earthing system.
At the earthing terminal, a permanent label marked with the words "SAFETY - ELECTRICAL EARTH DO NOT REMOVE" in English and Chinese shall be permanently attached to the earthing lead.
10.3 Lightning Protection System
The lightning protection system shall consist of an appropriately designed air termination network, connected via down conductors to the earthing system. Surge arrestors are to be installed in the low voltage switchboards.
Roof and down conductors shall be soft annealed copper strip 25 x 3mm. A test link shall be provided in the down conductors at ground floor level in a readily accessible position.
All protruding metal parts of the roof, e.g. hand rails, roof maintenance unit rails, etc., shall be bonded to the lightning protection network. The lightning protection system will be connected to the power system earth as suitable locations to comply with the requirements of IEC 1024.
Conductor joints, where necessary, shall be made with the use of a proprietary cad-weld type system. Bolted connections are not acceptable (except at test links).
10.4 Earth Electrodes
Earth rods shall be located as shown on the drawings. Each rod shall have a minimum diameter of 16 mm and be driven to a minimum depth of 2.4 M. Each rod shall be driven as deep as required in order to achieve the following minimum values of resistance when measured by the fall of potential method:
1. For each individual earth electrode, the product given by 10 times the number of earth electrodes to be provided
2. 1 for the whole earthing system
Unless agreed in writing, no other earthing arrangement or measured resistance values will be accepted.
An agreed inspection pit shall be installed at each earth electrode.
16 Inspection and Testing
Testing shall be carried out in accordance with the relevant IEC standards under which the equipment is manufactured and installed and in accordance latest edition of the following specifications:
1. IEC 364: Electrical installations of buildings
2. Code of Practice for the Electricity (Wiring) Regulations where appropriate.
16.2 Visual Inspection
A visual inspection shall be carried out to ensure the equipment is installed correctly and should include the following where appropriate:
1. Adequacy of working space, access and maintenance facilities.
2. Connection of conductors
3. Identification of conductors
4. Adequacy of the sizes of conductor in relation to current carrying capacity and voltage drop
5. Correct connection of all equipment with special attention to socket outlets, lamp holders, isolators, switches, residual current devices, miniature circuit breakers and protective conductors.
6. Presence of fire barriers and protection against thermal effects
7. Methods of protection against direct contact with live parts (including measurement of distances where appropriate), i.e. protection by insulation of live parts, or protect by barriers or enclosures.
8. Presence of appropriate devices for isolation and switching.
9. Choice and setting of protective and indicative devices
10. Labelling of circuits, fuses, protective devices, switches, isolators and terminals.
11. Selection of equipment and protective measures appropriate to adverse environmental conditions.
12. Presence of danger and warning notices.
13. Presence of diagrams, instructions and other similar information.
14. Connection of single pole devices for protection or switching in phase conductor only.
15. Methods of protection against indirect contact.
16. Prevention of mutual detrimental influence.
17. Presence of under voltage protective devices.
18. Erection method.
Where relevant, the following tests shall be carried out in the sequence indicated. In the event of any test failing to comply, that test and those proceeding (which may have been influence by the fault) shall be repeated after the fault has been rectified.
16.3.1 Continuity of Ring Final Circuit Conductors
The continuity of all conductors, including the circuit protective conductor of every ring final circuit, shall be verified.
16.3.2 Continuity of Protective Conductors
Every protective conductor shall be tested to verify that it is electrically sound and correctly connoted. The resistance of every protective conductor shall be measure with a testing voltage not exceeding 50 V ac at 60 Hz. The testing current shall be 1.5 times the design current of the circuit subject to a maximum of 25 A
16.3.3 Earth Electrode Resistance
The resistance of every earth electrode shall be measured to ensure that the earth resistance of the earth electrode will fulfill the purpose for which it has been installed.
16.3.4 Insulation Resistance
The insulation resistance of the installation shall be measures and the values shall not be less then the following minimum:
Circuit Nominal Voltage Test Minimum Insulation
(Volts) Voltage dc Resistance
(Volts) (M )
Extra-low voltage circuits when the 250 0.25 circuit is supplied for safety isolating transformer/SELV
Up to and including 500 V with the 500 0.5 exception of the above cases
Above 500 V 1 000 1.0
16.3.5 Insulation of Site Build Assembly
The insulation applied to the live parts of Site Build Assemblies for protection against direct contact shall be tested with an applied voltage equivalent to that for similar factory –built equipment.
16.3.6 Electrical Separation of Circuits
Electrical separation required for circuits for safety extra-low voltage equipment or required for protection against indirect contact, shall be inspected and tested with a testing voltage of 5000 V dc for one minute. The insulation resistance shall not be less than 5 M .
16.3.7 Protection by Barriers and Enclosure
Barriers and enclosure provided during erection to afford protection against direct contact shall be tested for compliance with IEC 529 “Degrees of protection provided by enclosures (IP Code)”.
16.3.8 Verification of Polarity
A test of polarity shall be carried out to all fuses, single pole control devices, centre contact bayonet and Edison-type screw lamp holders, socket outlets, etc. Proper test probes and a test lamp should be used where the main supply is available. A continuity tester should be used where the main supply is not available. Neon indicators shall not be used for this purpose.
16.3.9 Earth Fault loop Impedance.
A test shall be carried out to verify the effectiveness of the earthing by means of a phase-earth loop tester. The earth fault loop impedance should net exceed the requirements of Code 11 of the Code of Practice for the Electricity (Wiring)Regulations.
Every residual current-operated circuit breaker shall be tested for proper and satisfactory operation. The test shall be made by applying an ac voltage not exceeding 50 V rms across the neutral and earth terminals.
Alternatively the test may be carried out in accordance with the standard methods recommended by the device manufacturer.
16.3.11 Lightning Protect System
Every lighting protection system shall be tested in accordance with IEC 1024:
Protection of structures against lightning
16.3.12 Equipment Testing
Testing on electrical equipment and appliances supplied within the electrical installation contract, e.g. switchboards, generators, pumps, fans, etc. shall be carried out in accordance with the appropriate standard and the manufacturer’s recommended procedures.
16.4 Functional Testing
In additional to the above individual testing, the testing shall be extended to include the functional testing of the electrical systems when energized.
Functional test of the fixed electrical installation shall be conducted to produce evidence and verification that the electrical installation is capable of performing the designated function encapsulated in the original design.
All circuits shall be verified through switching operation to ensure that the circuits are installed in accordance with the designated design. The tests shall include (but not limited to):
1. On/Off switching of any lighting circuit to ensure that the lighting circuit is installed corresponding to the lighting switch, protective device and labelling.
2. Switching of general power circuits to ensure that each circuit corresponds to the protective device and that the protective device performs in accordance with the designated duty.
3. Switching of the main switch/isolator to ensure the corresponding circuit is properly controlled by the main switch/isolator.
4. Switching of all sub-main and main distribution circuits, e.g. bus ducts, cable feeders,underground cables, etc. to ensure the correct isolation of the connected circuit.
5. Switching of all changeover switches to ensure the changing over sequence corresponds to the design criteria.
6. Ensuring all the protective devices perform properly against the design criteria.
16.5 Deliverable documentation
The following drawings and documentation shall be supplied:
1. Type test and routine test certificates
17 Power Transformers
All power transformers shall be installed and tested in accordance with the latest edition of the following specifications:
1. IEC 726: Dry-type power transformers
The installation and testing of the transformers shall fully comply with any regulations and requirements of the local power supply authority.
Power ratings, voltage ratios, frequency and numbers of phases shall be as indicated on the drawings and/or detailed in the specifications. Tappings shall be provided with the range ±5% in 2.5% steps.
Vector group shall be DYn11 unless otherwise indicated on the drawings. A neutral terminal shall be provided for the secondary winding.
Dry type transformers shall be enclosed and have encapsulated windings. All enclosures shall be rated to IP20. Transformers shall be suitable for indoor installation and air cooled unless otherwise indicated on the drawings.
Transformers shall be supplied with one PTC sensor per phase and wired to a terminal strip.
18 Cage Type Induction Motors
All cage type induction motors shall be assembled, installed and tested in accordance with the latest edition of the following specifications:
1. IEC 34: Rotating Electrical Machines
All motors shall be designed for direct on line starting, unless otherwise indicated in this specification or on the drawings.
19 Deliverable Documentation
As a minimum, deliverable documentation shall include ‘As-Build’ versions of the following (where applicable).
1. Site Electrical Services (External Lighting, Cable Routing) A1
2. Reticulation Single Line Diagram(s) A1
3. Electrical Load List(s) A4
4. Electrical Cable Schedule(s) A4/A3
5. Switchboard/Switchgear Schedules(s) A4/A3
6. Switchboard/Switchgear Layouts(s) A1
7. Distribution Board Schedule(s) A4/A3
8. Distribution Board Layouts(s) A1
9. Luminaire Schedule (s) A4/A3
10. Main Cable Ladder, Main Trunking, Distribution Board Layout(s) A1
11. Cable Termination Diagrams A4/A3
12. Cable Routing Diagram(s) A1
13. Internal Lighting Layout(s) A1
14. External Lighting Layouts(s) A1
15. Small Power Layout (s) A1
16. Earthing & Lightning Protection Layout(s) A1
17. Generator Room Layout(s) A1
18. Electrical Switch room Layout(s) A1
19. Electrical Control Interface Block Diagram(s) A1
20. Security System Block Diagram(s) A1
21. Security System Layout(s) A1
22. Public Address System Block Diagram(s) A1
23. Public Address System Layout(s) A1
24. Electrical Installation Specification(s) A4
25. Calculation: System Fault Levels A4/A3
26. Calculation: System Loading A4
27. Calculation: Cable Sizing A4/A3
28. Calculation: Circuit Breaker Selection A4/A3
29. Calculation: Recommended Protection Settings A4/A3
30. Calculation: Lighting Levels A4
31. Electrical Equipment List (full imported/local list) A4/A3
32. Operation and Maintenance Manuals A4/A3/A1
33. Recommended Spare Parts List A4/A3
Additional documentation should be provided as required to enable the installation to be operated, maintained and improved by competent persons. The level of documentation required will be a the sole determination of the project engineer.
20 Diesel Generator Sets
Generators shall be manufactured, assembled and tested in accordance with the latest edition of the following specifications:
1. IEC 34: Rotating Electrical Machines
20.2 General Requirements
Generators shall be rated for duty class S1. The plant shall generate power for the total site, 24 hours per day, 7 days per week continuously.
Provision for future installation of additional generator sets shall be allowed for.
Generators shall be suitable for indoor operation (IP22) and be water-cooled.
20.3 Control Panels
Generator sets shall be provided complete with a generator control panel(s) incorporating all necessary engine and generator control systems, synchronization equipment, protection relays and main circuit breaker.
Relays other than panel mounted protective type relays shall be plug in type. Printed circuit assemblies shall be of the plug-in type.
Timers shall be electronic. Control switches shall be of the rotary type. An engraved label shall appear on the switch
All switches, relays, circuit breakers, contactors, etc, shall be clearly labelled with their circuit function.
All labels shall be "IVORINE" TRAFFOLYTE WHITE lettering on black background or black on a white background. Stick on plastic labels with NOT be permitted.
Labels shall be of minimum general height 6 mm and be fixed with round head metal thread screws nutted or suitable tapped escutcheon pins.
Provision shall be made for mechanical support and effective sealing of all cables entering the diesel control panels by means of glands and gland plates.
Equipment requiring connection to outgoing circuits shall be wired to terminal strips.
Starting equipment shall be designed for automatic starting. The starting time shall be not more than 10 seconds. Starting time shall be defined as the time from the initial start signal to acceptance of full load by the diesel alternator set.
Upon receipt of the start signal, the set shall immediately begin cranking and run up to speed and volts under governor and AVR controls as specified. Three (3) attempts to start of approximately 10 seconds duration each shall be provided. If a set fails to start the starting circuit shall be locked out and the appropriate alarm raised until restored manually.
When started each set shall run continuously until a stop signal is received or until a protection signal initiates shutdown.
When an automatic stop signal is received the connecting switch shall trip immediately and the set shall continue to run for a further run on, no load cooling time adjustable from zero to 30 minutes. At the end of this run on period the set shall automatically stop.
When a manual stop signal is received the set shall stop immediately.
The set shall be ready for reuse in any subsequent emergency immediately after it has shutdown and stopped running. The engine shall be prevented from starting while running down.
Should a start signal occur during the run-on cooling period, or whilst running in manual engine control, the set shall immediately take over the load if the control switch is in auto control.
All lead acid, battery-starting equipment including complete maintenance kit and connecting cabling shall be provided.
An engraved aluminum instruction plate shall be provided adjacent to the engine control panel giving brief and concise instructions on starting, stopping and attending the set when operating in the manual mode.
20.5 Protective equipment
As a minimum the engine shall be provided with the following protective equipment:
1. High water temperature
2. Low water pressure
3. Air flow failure
4. Low lubricating oil pressure
5. Low air pressure
6. Engine over speed
7. Engine under speed
8. Fail to start
9. Low fuel
10. Fuel empty
11. Other protection as recommended by the manufacturer
As a minimum the alternator shall be provided with the following protective equipment:
1. Alternator voltage high
2. Alternator voltage low
3. Over temperature protection
4. Thermal overload
5. Reverse power
6. Earth fault
7. Fail to synchronize
8. Other projection as recommended by the manufacturer
As a minimum the following other protective equipment shall be provided
1. Low battery level
2. Battery charger failure
As a minimum the engine shall be provided with the following instruments:
1. Tachometer (minimum dial size 100 mm) on instrument panel
2. Pressure gauges for lubricating oil pressure before and after oil filter
3. Pressure gauges fitted to flow and return water circuits
4. Water flow indicator (vane type preferred)
5. Temperature gauges for lubricating oil in sump and lubricating oil inlet and outlet to oil cooler
6. Temperature gauges on cooling water flow and return at lubricating oil cooler
7. Thermometers on jacket water inlet and outlet manifolds
8. Thermometers on raw water inlet and outlet at the water heat exchanger
9. Thermometer on air outlet from charge air heat exchanger
10. Engine temperature thermostat shall be fitted adjacent to the water outlet thermometer.
11. Lubricating oil pressure relay in each oil circuit after the oil cooler and oil filter
12. Exhaust pyrometers fitted at each cylinder head
13. Engine running time meter
14. Number of starts counter
15. Other instrumentation as recommended by the manufacturer
As a minimum the alternator shall be provided with the following instruments:
1. Volt meter
3. Frequency meter
4. Watt meter
5. Power factor meter
20.7 Emergency Stop
3.6.1 Provision shall be made for immediate emergency stopping of the plant. The emergency stop function shall be provided by a red mushroom head mechanically latched push button. It shall:
1. Directly isolate the starting system and fuel solenoid
2. Shut down all auxiliary equipment associated with the diesel alternator
3. Shut down of controls to prevent initiation of any other alarms due to the direct operation of the fuel solenoid
4. Operate the emergency stop indicator lamp on the control cubicle
5. Operate the remote monitoring
The emergency stop push button shall be located on the Diesel Control Panel.
20.8 Automatic Control And Synchronization
The system shall be fully automatic in operation, self monitoring and alarm indicative of approaching conditions that if allowed to continue would shutdown the Generation Plant.
It shall be possible for the generators to run in parallel with the supply utility, as stand alone units or in parallel with each other (and isolated from the supply utility).
The generation system shall operate automatically from initial manual start as follows:
1. The sets all start, the first to voltage and frequency closes onto the site bus and locks the remaining sets out.
2. Each of the remaining sets come under the control of the auto synchronizing unit and their frequency voltage and phase rotation adjusted to match the lead set.
3. As each set achieves lead set condition it initiates a close signal on the air circuit breaker, connecting it in parallel with the lead set.
4. Automatic load sharing operates to balance the loads evenly across the connected sets and/or in proportion to their capacity to generate.
5. Automatic load shedding/disconnection of generating sets is not a requirement.
Each set shall have a starting control, selection switch with two positions as follows:
1. Automatic: In this position the starting and stopping of the set shall be controlled from the Automatic Start control system specified.
2. Manual: In this position the starting and stopping of the set shall be controlled by two push buttons START and STOP respectively, mounted adjacent to the starting control selection switch.
20.9 D.C. Power Supply
All protective relays and instruments shall be provided as follows:
1. 24 V D.C. lead acid battery system
2. A 24 V constant potential output current limiting battery charger
Each battery shall be of ample capacity to maintain control under the worst circumstances for a period of 24 hours while disconnected from its charger without its voltage dropping to a level at which control malfunction shall occur.
The batteries shall be suitably mounted in the control cabinet and located so that the cells are readily accessible for maintenance and so that the electrolyte level can be easily determined through the sides of the polystyrene cell containers.
Battery chargers shall be complete with voltmeter and ammeter, fuses, switchgear and facilities for manual boost charging. It shall be capable of restoring the battery to a 90% charged condition from a 50% charged condition within eight hours while carrying the standing D.C. Control Load.
Battery charger ammeter scales shall be blue zoned to indicate the recommended auto float charge rate and white zoned to indicate the boost charge rate and red zoned to indicate charging outside manufacturer's charging recommendations.
D.C. circuits shall be fused in the positive and negative connection and be continuously monitored.
20.10 Noise Reduction
An exhaust silencer shall be fitted to the exhaust pipe for each engine and supported as necessary. Each silencer shall be selected with due regard to the noise level limitations specified herein and to suit the particular characteristics of the engines offered.
Noise reduction systems (i.e. better silencers, sound proof enclosures, etc) shall be designed to limit the total noise level at the site boundary due to less than 40 dBA.
20.11 Deliverable Documentation Requirements
The following drawings and documentation shall be supplied:
1. Single line diagrams
2. Protection scheme block diagrams
3. Schematic diagrams
4. Control scheme block diagrams
5. Termination and wiring diagrams
6. General arrangement diagrams
7. Relay discrimination curves
8. Current transformer magnetization curves
9. Type test and routine test certificates
10. Operating and maintenance manuals
11. Parts list (description, manufacturer, catalogue number, etc)
21 Hazardous Areas
All electrical equipment located in hazardous areas shall be selected, installed and commissioned in accordance with the latest edition of the following specifications:
1. IEC 79: Electrical apparatus for explosive gas atmospheres