Electrical Works
A Guide to
Specifications
Sewer Selection
and Installation
ISSUE: 01
JANUARY 2007
PED/SDQS/EWS/SPEC/0507/003
Electrical Works Specifications
Electrical Works Specification
Section 1
Low Voltage Switchboard and Components Specification
Section 2
Standby Generator Specification
Section 3
Small Power and Lighting
Section 4
High Tension Components Specifications
Section 5
Motor Specification
Section 6
Low Voltage Cable Specification & Installation
Section 7
Earthing, Lightning and Surge Protection
Electrical Works Specifications
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February 2007
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Electrical Works Specifications
Page
Section 1 - Low Voltage Switchboard and Components Specification
1.0
Design and Construction
1-1
2.0
Dimension
1-1
3.0
Capacitor Bank
1-2
4.0
Contactor For Capacitor Switching
1-3
5.0
Busbars and Small Wiring
1-3
6.0
Air Circuit Breakers
1-4
7.0
Moulded Case Circuit Breaker (MCCB)
1-4
8.0
Miniature Circuit Breaker (MCB)
1-5
9.0
Residual Current Circuit Breaker (RCCB)
1-5
10.0
Fuses In General
1-5
11.0
Current Transformers
1-6
12.0
Indicating Instruments
1-6
13.0
Electronic Overload Relay
1-6
14.0
Motor Starters
1-11
15.0
Indicating Lamps and Fittings
1-17
16.0
Push Buttons
1-18
17.0
Anti-Condensation Heaters
1-18
18.0
Labels
1-18
19.0
Padlocks
1-19
20.0
Cable Entries
1-19
21.0
Junction Box
1-19
Appendix A -
Metal Treatment and Painting Procedures (ElectroGalvanised Metal Sheet)
A-1
Appendix B -
Floor Mounted Switchboard Compartment Dimensions
B-1
Appendix C -
Typical Switchboard Drawings (Floor Mounted, Wall
Mounted and Outdoor Type)
C-1
Appendix D -
Digital Protective Relay Standards
D-1
Appendix E -
Digital Protective Relay Operating Conditions
E-1
Appendix F -
Digital Protective Relay Metering Functions
F-1
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Electrical Works Specifications
Appendix G Appendix H -
Digital Protective Relay Network, Machine and
Switchgear Diagnosis
G-1
Meaning of Colours from IEC 60073 and IEC 60204-1
H-1
Section 2 - Standby Generator Specification
1.0
General
2-1
2.0
Engine
2-1
3.0
Lubrication System
2-1
4.0
Exhaust Fan
2-1
5.0
Radiator Air Discharge
2-2
6.0
Fuel System
2-2
7.0
Engine Governing
2-2
8.0
Engine Instrumentation
2-2
9.0
Alternator And Exciter
2-3
10.0
Voltage Regulation
2-3
11.0
Voltage Waveform
2-3
12.0
Starting System
2-3
13.0
Fuel Supply System
2-4
14.0
Protective Devices
2-5
15.0
Control Panel
2-6
16.0
Automatic Mains Failure (AMF) Switchboard
2-6
17.0
Changeover Contactor
2-8
18.0
Earthing System
2-9
Section 3 - Small Power and Lighting
1.0
Material Panel
3-1
2.0
Distribution Board
3-1
3.0
PVC Electrical Conduit and Fittings
3-2
4.0
Spacer Bar Saddles
3-2
5.0
Distance Saddle
3-2
6.0
Ceiling Fan
3-2
7.0
Light Fittings and Ancillary Equipment to Lamps
3-3
8.0
Street and Perimeter Lighting
3-4
9.0
Materials and Equipment
3-7
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Electrical Works Specifications
Section 4 – High Tension Components Specifications
1.0
11 kV / 22kV Vacuum Circuit Breaker Specification
4-1
2.0
Specification for 11 kV Oil Immersed Natural Cooled Transformers
4-6
3.0
Cast Resin Transformer
4-11
4.0
11 kV Cable Specification
4-17
Section 5 – Motor Specification
1.0
Submersible Motor
5-1
2.0
Surface Mounted Motors
5-2
Section 6 – Low Voltage Cable Specification & Installation
1.0
Type of Cable and Application
6-1
2.0
Cable Installation
6-2
3.0
Requirements
6-4
4.0
Cable Trench
6-4
5.0
Cable Ducts
6-6
6.0
Cable Termination and Jointing
6-6
7.0
Cable Accessories
6-6
Section 7 – Earthing, Lightning and Surge Protection
1.0
Common Earth Termination Network
7-1
2.0
Surge Protection
7-3
3.0
Lightning Protection
7-5
Electrical Works Specifications
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Section 1 - Low Voltage Switchboard and Components Specification
Section 1
Low Voltage Switchboard and
Components Specification
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1 – Low Voltage Switchboard and Components Specification
Page
Section 1 Low Voltage Switchboard and Components Specification
1.0
Design and Construction
1-1
2.0
Dimension
1-1
2.1
Appearance
1-1
2.2
Wall Mounted
1-2
2.3
Floor Mounted
1-2
2.4
Outdoor Type
1-2
3.0
Capacitor Bank
1-2
4.0
Contactor For Capacitor Switching
1-3
4.1
Up To 60 kVAr – 400 V
1-3
4.2
Greater Than 60 kVAr – 400 V
1-3
5.0
Busbars and Small Wiring
1-3
6.0
Air Circuit Breakers
1-4
7.0
Moulded Case Circuit Breaker (MCCB)
1-4
8.0
Miniature Circuit Breaker (MCB)
1-5
9.0
Residual Current Circuit Breaker (RCCB)
1-5
10.0
Fuses In General
1-5
11.0
Current Transformers
1-6
12.0
Indicating Instruments
1-6
13.0
Electronic Overload Relay
1-6
13.1
Protection Relays
1-6
13.2
Digital Protective Relay
1-7
13.2.1 General Design Requirements
1-7
13.2.2 General and Practical Operating Requirements
1-8
13.2.3 Installation and Requirements
1-8
13.2.4 Protection
1-9
13.2.5 Control and Monitoring
1-9
13.2.6 Metering
1-10
13.2.7 Network, Machine and Switch Gear Diagnosis
1-10
13.2.8 Relay Diagnosis
1-10
13.2.9 Programming and Configuration Software
1-10
13.2.10 User Machine Interface
1-10
13.2.11 Communication
1-11
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Section 1 – Low Voltage Switchboard and Components Specification
14.0
Motor Starters
1-11
14.1
Direct-On-Line (DOL)
1-12
14.2
Star Delta
1-12
14.3
Auto Transformer
1-12
14.4
Soft Starter
1-12
14.4.1 Performance Functions
1-13
14.4.2 Power Connection
1-13
14.4.3 Protection Functions
1-13
14.4.4 Sundry Features
1-13
14.4.5 Function Facilitating the Integration of Control System 1-14
14.4.6 Options
1-14
14.5
Variable Speed Drive
1-14
14.6
Contactor for Motor Starters
1-17
15.0
Indicating Lamps and Fittings
1-17
16.0
Push Buttons
1-18
17.0
Anti-Condensation Heaters
1-18
18.0
Labels
1-18
19.0
Padlocks
1-19
20.0
Cable Entries
1-19
21.0
Junction Box
1-19
Appendix A -
Metal Treatment and Painting Procedures (ElectroGalvanised Metal Sheet)
A-1
Appendix B -
Floor Mounted Switchboard Compartment Dimensions
B-1
Appendix C -
Typical Switchboard Drawings (Floor Mounted, Wall
Mounted and Outdoor Type)
C-1
Appendix D -
Digital Protective Relay Standards
D-1
Appendix E -
Digital Protective Relay Operating Conditions
E-1
Appendix F -
Digital Protective Relay Metering Functions
F-1
Appendix G -
Digital Protective Relay Network, Machine and Switchgear
Diagnosis
G-1
Appendix H -
Meaning of Colours from IEC 60073 and IEC 60204-1
Electrical Works Specifications
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H-1
ii
Section 1 - Low Voltage Switchboard and Components Specification
SECTION 1 - LOW VOLTAGE SWITCHBOARD &
COMPONENTS SPECIFICATION
1.0 DESIGN AND CONSTRUCTION
Switchboards, sub-switchboards, control panels, distribution board and all other equipment shall
comply with the relevant current British Standard and IEC specification.
Each item shall be enclosed in a vermin proof steel cubicle of rigid construction and made of sheet
steel of such thickness that it is free from distortion and with no entries for insect whatsoever. Where
two or more cubicles are fitted together they shall form a continuous flush front. All units shall be
floor mounted unless otherwise specified.
The door of the switchboard shall be hinged such that they can be operated through an arc of 180
degrees. A minimum of 3 hinges shall be chrome-plated and of a good quality.
All switchboards, together with switch gears, control gears, etc. shall be capable of withstanding fault
conditions of not less than 31 MVA at 415 V for 3 seconds as defined in IEC 60439-1 and off Form
3B.
The cubicle framework shall be fabricated from rolled steel angle sections and shall be selfsupporting when assembled, uniform in height and depth from front to back. The rigid construction
shall be designed to withstand without any sag, deformation or warping, the loads likely to be
experienced during normal operating, maintenance or maximum fault conditions. Sheet steel used
shall not be less than 2.3 mm anti-rust zinc. Cross-structs shall not be used.
The manufacturer's name shall be incorporated on the switchboards.
The interior and exterior of each cubicle shall be finished with light gray paint (ICI Ref. No: ICI 104
or OXYPLAST paint: FF160/8250/CS9. The cubicle shall be off electro-plated mild steel sheets. It
shall be treated to prevent corrosion. Refer to Appendix A – Metal Treatment and Painting Procedure
(Electro-Galvanised Metal Sheet). All cubicles shall be dust, insect and vermin proof. The interior of
each piece of equipment shall be clearly marked to show phases and to this end coloured plastic
sleeving shall be employed. Plastic tape will not be permitted.
Steelwork necessary for supporting the switchboards shall also be included.
2.0 DIMENSION
2.1
Appearance
Panel thickness
Frame Thickness
Electrical Works Specifications
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2.3 mm and 90 µm of paint thickness
2.3 mm and 90 µm of paint thickness
Sec 1 - 1
Section 1 - Low Voltage Switchboard and Components Specification
2.2
Wall Mounted
Wall mounted switchboard shall not be more than 1.6 m height and located 0.2 m from floor. Where
necessary, a step or a working platform that is insulated must be provided.
For a range of up to 100 Amps switchboard: •
•
•
•
2.3
Incoming compartment
: 450 mm
Subsequent compartment
: 450 mm
Cable compartment
: 125 mm
Cables to be glanded at bottom entry of the switchboard
Floor Mounted
Floor mounted switchboard shall not be more than 2.1 m height and located 0.2 m from floor. Where
necessary, a step or a working platform that is insulated must be provided.
Refer to Appendix B - Floor Mounted Switchboard Dimensions (up to 100 A, more than 100 A up to
400 A, 400 A and above)
2.4
Outdoor Type
The outdoor main switchboard shall be off self-contained, free standing or wall mounted
weatherproof cabinets to be constructed of electro-galvanised metal plates. Control indication and
alarm facilities shall be mounted on internal doors enclosing compartments housing electrical plant
and equipment. Wall mounted outdoor weather proof control panel shall come with awning extended
by at least 2 m from wall and floor mounted outdoor weather proof control panel shall come with roof
awning extended 2 m from the panel. External doors with security locking facilities and double roofs
on cabinets to reduce solar effects shall be provided.
Refer to Appendix C – Typical Switchboard Drawings (floor mounted, wall mounted and outdoor
switchboard).
3.0 CAPACITOR BANK
The power factor (p.f.) of the assembly shall be design for 0.95 or better. Should it be less than 0.95,
provision shall be made in the panel to incorporate additional power factor correction to improve the
power factor to the minimum value required. Power factor regulation shall be of multiple steps,
individual capacitors are allowed only if the load is lower than 5 kVAr. In any case the total power
factor for the assembly shall not fall below 0.95. Where multiple steps are provided, in case of failure,
the smallest step shall be duplicated to act as a back-up. Capacitors shall be protected with its
individual capacitor switching contactors and MCCB.
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Section 1 - Low Voltage Switchboard and Components Specification
4.0 CONTACTOR FOR CAPACITOR SWITCHING
4.1
Up to 60 kVAr – 400 V
The contactors shall be specifically designed for capacitor switching. Particularly shall be included a
set of contact and current limiting resistors which shall be switched off after initial switching peak
current. The contactors shall comply with IEC 70 and IEC 831. All contactors will have the reference
number on the front of the contactor. All contactors shall be climate proof as standard. The rated
impulse voltage shall be 8 kV. The contactor shall work up to 55oC ambient temperature without
derating. The coil operating range shall be between 0.85 and 1.1 times of the rated voltage (AC).
All contactors shall be finger safe as standard or with adaptable covers and available in a variable
composition for auxiliary contact. The safety clearance on the front of the contactor shall be less than
15 mm. The coil wire insulation shall be Class F. The contactors shall be cadmium free and built with
recyclable materials. The contactor shall include a system to prevent resistor burning in case of
abnormal pole operation.
The switching contactors shall be of AC3 load switching.
4.2
Greater than 60 kVAr – 400 V
The switching contactors shall be of AC4 load switching. All contactors shall incorporate air break or
vacuum contactor rated for frequent duty in accordance with IEC 60947.
5.0 BUSBARS AND SMALL WIRING
Busbars marking and arrangement, connection and grade of copper shall all comply as appropriate
with BS EN 13601.
The switchboards shall be so arranged that the busbars run horizontally through each sectionalised
length and shall comprise three or four bars as appropriate fabricated from hard drawn high
conductivity copper rigidly mounted on non-hygroscopic insulators with connection from the busbars
to the circuit breakers and switches effected by copper bars or cables securely clamped to the bars and
identified by means of coloured plastic sleeving or painting to indicate the phase colours. All cable
supports shall be non-hygroscopic.
All small wiring shall be of adequate size to suit their current ratings but in any case not less than 1.5
square mm. in section for cables, insulated with PVC and shall be fixed securely without strain by
cleats of the compression type. For the purpose of identification different insulant colours shall be
provided to distinguish the various circuits and each connection shall terminate at an approved type of
terminal block placed in an easily accessible position for testing at site with coded ferrules of an
approved type at both ends of each connector. No connectors or soldered joints will be permitted in
the wiring. The wiring shall be formed in a neat and systematic manner, with cables supported clear
of panels and without cross-overs. Bushers shall be provided wherever necessary to prevent chafing
of cables.
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Section 1 - Low Voltage Switchboard and Components Specification
6.0 AIR CIRCUIT BREAKERS
All air circuit breakers used for the incoming shall be of four pole. All other air circuit breakers
downstream shall be of triple pole. Association of Short-Circuit Testing Authority (ASTA) or
Keuring Van Electrotechnische Materialen (KEMA) certified for a minimum rupturing capacity of 26
MVA at 415 V with a short time rating of 3 seconds.
Air circuit breakers shall be used for all current ratings of 600 A and above.
Units shall be hand charged spring closed with ratings and instrumentation as specified and of the
horizontal draw-out isolation type so arranged that they may be completely isolated from the
switchboard except that secondary circuits shall not be broken with the circuit breaker in the “test”
position in order to permit test tripping or closing.
Closing mechanism shall be of trip free type and incorporate mechanical "ON/OFF" and "SPRING
CHARGED/SPRING FREE" indicators mechanically and positively coupled to the operating
mechanism and mechanically interlocked to prevent:(i)
Withdrawal or plugging of the circuit breaker in the closed position
(ii) Closure unless either fully plugged or fully isolated
(iii) Opening of cubicle door until breaker is isolated
(iv) Prevent insertion of the racking handle when the cubicle door is open
Contacts shall be of adequate rating to ensure that they can carry continuously full rated current
without overheating, damage or deterioration and shall be individually spring loaded, hard silver
plated of the magnetically "blown on" type so arranged that electro-magnetic forces arising under
short circuit conditions do not tend to reduce contact pressure. The arc chutes shall be removable on
site. No safety clearance shall be required around drawout circuit breakers. For fixed circuit breakers,
150 mm of free space shall be provided above the arc chutes to allow removal of the latter. Screening
shutters actuated automatically with the circuit breaker isolated and withdrawn and capable of
padlocking in the screened position. The arc chutes shall be equipped with metal filters to reduce
effects perceptible from the outside during current interruption. The breaker shall have the option to
install shunt trip coil energised through relay contacts, “Close” and “Trip” push buttons.
7.0 MOULDED CASE CIRCUIT BREAKER (MCCB)
Moulded case circuit breakers shall comply fully with BS 4752: Part 1 and the case shall be of
moulded insulating materials of good mechanical strength and non-tracking properties. The tripping
mechanism shall be calibrated in compliance with British Standards at the factory and the breaker
shall be sealed to prevent tampering.
MCCBs shall be used for all current ratings less than 600 A.
MCCBs shall be rated at not less than 25 kA 0.3 sec. of below 100 A and 50 kA 0.3 sec. of above 100
A.
MCCBs shall be of manual or automatic operation as required. The automatic type shall each
incorporate a trip unit to provide overload and short circuit protection. The trip unit for each pole
shall provide inverse time delay under overload conditions and instantaneous magnetic tripping for
short circuit protection, with five adjustable trip setting. The trip units in all the circuit breakers shall
be interchangeable.
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Section 1 - Low Voltage Switchboard and Components Specification
The MCCB shall be so designed that when on tripped condition, the circuit breaker cannot be
switched on again unless it has been reset by switching to OFF position first. The operating
conditions (i.e. ON, OFF or TRIP) of the circuit breaker shall be clearly indicated.
MCCBs shall be Single Pole and Neutral (SPN), Double Pole (DP) or Triple Pole and Neutral (TPN)
type as required. However, MCCBs at the incoming shall be of Four Pole. The construction and
operation of the circuit breakers shall be such that as a fault occurs, all the poles of the circuit
breakers shall operate simultaneously to isolate and clear the fault efficiently and safely without any
possible risk to the operator or to the installation. Each circuit breaker shall incorporate "trip-free"
mechanism to ensure that the breaker cannot be held closed in fault conditions.
The operating mechanism of the circuit breakers shall be hermetically sealed at the factory and all
metallic parts associated with the operating mechanism shall be treated against rust and corrosion.
The short-circuit breaking capacity of the MCCB shall not be less than the maximum prospective
fault levels at the point where the MCCB is installed.
8.0 MINIATURE CIRCUIT BREAKER (MCB)
MCBs shall have a breaking capacity of not less than 5 kA (rms). They shall comply with BS EN
60947-2, BS EN 60898 or IEC 157-1, fully tropicalised and suitable for use on a 240/415 V, 50 Hz
AC system and up to an ambient temperature of 400 °C.
MCBs shall be quick-make, quick-break and trip-free type complete with de-ion arc interrupters. The
tripping elements shall be thermal magnetic type with inverse time delay over-current and
instantaneous short circuit characteristics. They shall be able to respond to overload and the response
shall be independent of variations in ambient temperature.
MCBs shall be manually operated by means of toggle type handles having visual indication of
whether the breaker is opened, closed or tripped. Multi-pole breakers shall be provided with
common-trip mechanisms for simultaneous operation of all the poles.
9.0 RESIDUAL CURRENT CIRCUIT BREAKER (RCCB)
RCCBs shall be current operated type complying with IEC 61008-1. RCCBs shall be used for
incoming rating of up to and including 60 A. They shall be either double pole or four pole type. The
sensitivity, unless otherwise specified, shall not exceed 100 mA for double pole type and 300 mA for
four pole type. Test push button and visual indication for ‘ON’ and ‘OFF’ shall be provided. They
shall be equipped with screw clamping type cable terminals.
10.0 FUSES IN GENERAL
Fuses shall comply with BS 88. Unless otherwise specified all fuses shall be of the HRC type and of
an approved make. Fuse bases and carriers shall be of the unbreakable type and shall be arranged for
safe and easy replacement of fuses. All live connections including fuse base contacts shall be
efficiently shrouded. The fuses fitted on a circuit shall be of such rating as to give maximum
protection to the apparatus it supplies.
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Section 1 - Low Voltage Switchboard and Components Specification
11.0 CURRENT TRANSFORMERS
Current transformer shall comply with BS 3938 and shall have short time ratings not less than that of
the switch panels in which they are incorporated.
Identification labels shall be fitted giving type, ratio, rating, output and serial numbers and duplicate
rating labels are to be fitted on the exterior of the mounting chambers suitably allocated to enable
reading without the removal of any cover or metal sheeting forming part of the structure of the
switchboards.
All current transformers shall be of Class 3, 5 VA for all metering circuits shall, unless otherwise
stated. For all protection circuits, the current transformer shall be of 10P10 and a burden of 15 VA.
For power factor regulation the current transformer shall be of Class and a burden of 15 VA.
12.0 INDICATING INSTRUMENTS
Indicating instruments on switchboards shall be flush mounted and shall generally be of the same
pattern and appearance throughout. They shall be of a type giving no parallax error and their normal
maximum reading shall be at about 60% full-scale deflection. Ammeters in motor starter circuits
shall be capable of withstanding the starting current. All voltmeter shall have selector switches
enabling any phase to phase to neutral voltage to be read.
Indicating instruments shall be fitted with zeroing devices and shall be positioned with dial centres
not more than 1.85 m and not less than 0.75 m above floor level. Indicating instruments shall comply
with BS 89 and shall be of industrial grade accuracy.
Panels with incoming 400 A and above, a digital power meter shall be provided.
13.0 PROTECTION RELAYS
13.1 Electronic Overload Relay
These relays shall have definite time characteristics: current threshold and time based function.
The relay shall be functional in the case of long starting time or frequent starting. The relay shall
provide protection at minimum for over-current, rotor locked and phase failure. The relay shall be
incorporate individual adjustable trip time and delay time setting for staring, over-current and rotor
locked.
The over-current trip preset value for the relay shall be at minimum 110% of the operating current
and with adjustable range. The relay shall incorporate LED indication light to assist fast diagnostic of
status, operation and type of failure. The allowable error of the relay shall be 5% for current and time.
The relay shall confirm to IEC 60255-6 and IEC 60947 standard. The degree of protection shall be
IP20 and confirming to IEC 60529 standard.
The relay shall be operation in temperature up to 60oC in normal operation without derating and
confirming to IEC 60947-4-1 standard. The relay shall withstand surge up to 6 kV and confirming to
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Section 1 - Low Voltage Switchboard and Components Specification
IEC 61000-4-5 standard. The sensing and control of the relay shall be through built-in current
transformer and micro CPU.
13.2 Digital Protective Relay
The Digital Protective Relay shall comply with the most relevant national, international standards and
recommendations for industrial electrical distribution (IEC, EN, UL, and CSA). The Digital Protective
Relay shall be CE marked, conforming to European Low Voltage (73/23 EEC and 93/68 EEC) and
EMC (89/336/EEC).
Refer to Appendix D – Digital Protective Relay Standards.
13.2.1 General Design Requirements
•
Technology and functionality:
The Digital Protective Relay design shall be based on a microprocessor technology and shall
accommodate a hardware and software architecture consisting of a multifunction protection and
control platform with logic/analogue inputs and outputs, including Protections, Metering, Control &
Monitoring, User Machine Interface with alphanumeric display, Communication Interface, Network,
Machine, Switch gear and relay diagnosis functionality.
•
Programming and configuration
The Digital Protective Relay shall be programmable and configurable with an appropriate userfriendly setting software using a MS Windows program running on a standard PC. The programming
and configuration shall be carried out locally (front access) through a RS 232 port or remotely
through a communication network, mainly an Engineering LAN (E-LAN) with adequate passwords to
prevent any unwanted intrusion.
Programming and configuration shall also be able to be prepared on a PC file directly (unconnected
mode) and down-loaded locally or remotely into the relay.
•
Hardware and software architecture
The hardware and software architecture shall be modular and disconnectable to adapt the protection
and control unit to the required level of complexity of the applications.
The architecture shall allow future extensions by simple and easy hardware and firmware upgrading
of the protection and control unit and shall be designed to enable upward compatibility between
Digital Protective Relay of different generations of the manufacturer.
The Protective Digital relay shall accommodate digital and isolated inputs/outputs. The inputs shall
be used to monitor the status of the complete panel as well as receive external signal while the outputs
shall be used for circuit breaker, inter-tripping between panels and remote alarms.
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Section 1 - Low Voltage Switchboard and Components Specification
13.2.2 General and Practical Operating Requirements
The Digital Protective Relay shall operate according to the following conditions: •
The circuit breaker control output relay contact shall be capable of withstanding a 30A DC
current for 0.2 seconds and 2,000 operating cycles according to ANSI C37.90-Clause 6.7.
•
Other logic output relay contacts shall be capable of withstanding a 8A DC/AC steady state
current
•
Logic input pilot voltage shall be rated as per the auxiliary power supply of external driven
digital signals from the control system (RTU or PLC) and shall comply with IEC 60011-32.
•
Current carrying terminal from current sensors shall be automatically short circuited when
withdrawing current sensor modules.
•
Provisions shall be made in the switchgear cubicle for testing and calibrating the relay by
current injection using an external source, without disconnecting the permanent wiring.
•
CT/VT and Trip coil supervision facilities shall be provided to check the wiring circuit
continuity with relevant alarms and messages.
•
The Digital Protective Relay shall be continuously rated and shall maintain the setting accuracy
without setting drift over time and full range of auxiliary voltage variations as per the
requisition.
•
The Digital Protective Relay shall be capable of withstanding the output current of the
associated current transformers corresponding to a primary current equal to the specified short
circuit withstand current and time of the assembly ( 4 In permanent, 100 In 1 second).
Refer to Appendix E – Digital Protective Operating Conditions.
13.2.3 Installation and requirements
The Digital Protective Relay shall be able to be flush mounted or mounted inside the Low Voltage
compartment and shall have an IP52 mechanical protection degree according to IEC 60529.
To operate properly and to achieve satisfactory operating quality, the Digital Protective Relay shall be
installed so that it shall be protected against EMC, and the following points shall be required: •
•
•
•
•
•
A single equipotential earth system used as the site potential reference
A power distribution with TN-S earthing system
Separation of different kinds of cables (power, power supply, auxiliary, data, measures)
Use of screened cables for data and measure
A power supply protection (filtering, over voltage protection)
Equipment and installation protection against the indirect effects of lightning
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Section 1 - Low Voltage Switchboard and Components Specification
13.2.4 Protection
The Digital Protective Relay shall integrate all the necessary ANSI code protections according to the
different levels of applications and shall provide wide setting ranges mainly for current protections
and a large choice of tripping curves through two setting groups (normal/back-up mode network)
operated by logic input: -
Definite Time (DT) curve
IDMT curves set by T time delay or TMS factor, including:IEC curves (SIT, VIT/LTI, EIT)
IEEE curves (MI, VI, EI)
Usual curves (UIT, RI, IAC)
Customised tripping curve possibilities shall be available for specific Phase, Earth fault over
current.
ANSI code
Tripping curve
Threshold
Tripping time delay
50/51(Low, Mid-end
solutions/applications)
DT
IDMT
Is set point
0,1 to 24 In
0,1 to 2,4In
Inst: 0,05 sec to 300
sec
0,1 sec to 12,5 sec at
10 Is
50N/51N(Low, Mid-end
solutions /applications)
DT
IDMT
Is0 set point
0,1 to 15 In0
0,1 to 1 In0
Inst: 0,05 sec to
300sec
0,1sec to 10 Is0
•
Overload protection shall be based on RMS current value (Minimum 13th Harmonic) and shall
take the ambient temperature into account.
•
Phase over current and earth fault protection shall have an adjustable timer hold to allow restriking fault detection
•
Earth fault protection shall integrate a H2 Harmonic restraint for transformer start-up inrush
current to be activated or inhibited
•
Alternative over current setting groups shall be selectable by logical conditions through logic
inputs, to adapt a fast protection plan change as well as setting facilities for thresholds and time
delay adjustment.
•
The Digital and protective Relay shall allow the use of upstream and logic discrimination in a
cascading scheme or closed loop applications.
13.2.5 Control and monitoring
The Digital Protective Relay shall basically carry out all the ANSI code Control and Monitoring
functions necessary to control the Circuit Breaker or Contactor for electrical operations. These
operations shall be performed from pre-defined functions using logic inputs/outputs and shall be
processed from internal and external data.
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Section 1 - Low Voltage Switchboard and Components Specification
13.2.6 Metering
The Digital Protective Relay shall include accurate measurement processing functions and shall
display the metering data on the User Machine Interface to operate the different applications and
carry out commissioning and maintenance as per Appendix F – Digital Protective Relay Metering
Functions.
13.2.7 Network, machine and switch gear diagnosis
The Digital Protective Relay shall provide diagnosis facilities for process management and
maintenance purpose as per Appendix G – Digital Protective Relay Network, Machine and
Switchgear Diagnosis.
13.2.8 Relay diagnosis
The Digital Protective Relay shall contain self-test diagnosis facilities to: •
•
Detect internal relay failures that may cause nuisance tripping or failed fault tripping
Set the relay in fail-safe position leading to a fall-back position to avoid any unwanted tripping
if a major internal failure is detected. A Watchdog relay with change over contact (NO+NC)
shall provide an alarm or information to activate a back-up protection. Any minor failure shall
not interrupt the protection function operations and the relay shall operate in downgraded mode
Inform for maintenance operation
Detect unplugged connectors resulting in a major internal failure
Check the hardware configuration:-
-
The absence or failure of a remote module shall be considered as a minor failure.
The absence or failure of a Logic input/output module shall be considered as a major failure
•
•
•
13.2.9 Programming and configuration software
The Digital Protection Relay shall use a user-friendly setting and operating multi-lingual software in
Windows environment
13.2.10 User Machine Interface
•
The Digital Protective Relay shall incorporate a User Machine Interface (or UMI) with an
alphanumeric graphical LCD and back-light display screen indicating:-
-
Measurement values
Operating messages in major international languages
System maintenance messages
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February 2007
Sec 1 - 10
Section 1 - Low Voltage Switchboard and Components Specification
13.2.11 Communication
•
The Digital Protective Relay shall be communicating through one or two communication ports
and integratable in communication architecture with information remote access. It shall be able
to be interfaced to two types of communication networks providing access to data on each
communication port, via:-
-
A multi-protocol based Supervisory Local Area Network (S-LAN) to supervise functions
regarding the installation and the electrical network from a supervision system (SCADA or
RTU).
Modbus based Engineering Local Area Network (E-LAN) to configure, set up the relay, collect
operating and diagnosis information, monitor the status of the electrical network and run
diagnostics on electrical network incidents from the programming and configuration software.
-
14.0 MOTOR STARTERS
The starters shall be of the following types:
(a)
(b)
(c)
(d)
(e)
Up to 3.7 kW
Above 3.7 and up to 7.5 kW
Above 7.5 and up to 22 kW
More than 22 kW
75 kW and above
Direct-On-Line starters
Star/Delta starters
Auto-transformer starters
Soft starter
Variable Speed Drive
Motor starters shall be in accordance with IEC 60947-1 and IEC 60947-4-1 and equipped with
overload and no volt protection. Where MCC are supplied as a stand alone unit, it shall comply with
the switchboard specification. Single phase and earth leakage protection shall be deemed to be
included. Starters shall be of the contactor type with coils wound for 230Volts 50 cycles operation.
All starters shall be capable of at least 15 starts per hour at 100% full load torque. The motor starter
shall be of rating to carry the full load current of its rated duty at its most severe load conditions
All motor starters shall be of automatic and manual control type with “Start/Stop/Reset" facility,
MCCB mechanically inter-lockable with access door, independent control circuit with fuses/MCB
and provision for remote control as required.
Individual starters shall be provided for each equipment and housed in a separate compartment, which
are mounted in switchboard cubicles. The starter cubicles shall be easily accessible for maintenance
purpose constructed of ingress protection IP42. Unless otherwise approved, the metal surface of the
cubicle wall adjacent to the contactors shall be protected by fireproof insulating material. All
secondary wiring shall be so arranged and protected as to prevent it being damaged by arcing. Where
draw-out patterns motor starter is specified, the starter shall be easily withdrawable and can be
replaced with another spare starter of similar rating.
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February 2007
Sec 1 - 11
Section 1 - Low Voltage Switchboard and Components Specification
14.1 Direct-On-Line (DOL)
For DOL starters, an air-break tripole electromagnetic contactor starter with a normal open retaining
auxiliary contact, shall be provided. The auxiliary contact shall be complete with one closing/holding
coil 230 V, 50 Hz (no-volt coil inherent) and EOCR with resetting devices and auxiliary signal lamp
contact. The reset push button shall be accessible from outside.
14.2 Star Delta
For Star Delta starters, an air-break triple pole electromagnetic ‘LINE’ contactor fitted with necessary
auxiliary contacts, closing / holding coil, EOCR, etc. shall be provided. The EOCR shall be connected
in the Delta position and thus give automatic single phase protection. The starter shall contain an air
break triple pole and neutral ‘STAR’ contactor fitted with the necessary auxiliary contacts and an air
break triple pole and neutral ‘DELTA’ contactor fitted with the necessary auxiliary contacts. The Star
Delta contactors shall be electrically and mechanically interlocked. The starter shall be complete with
necessary time delay contacts to effect the correct sequence of operation.
14.3 Auto Transformer
Auto Transformer shall be fitted with multipole contactors which increase the supply voltage to the
starter by changing out sections of the starting transformer tabs. The three phase, air cooled auto
transformer shall be accommodated in a separate section mounted at the top within the switchboard
cubicle of the starter. Tapping shall be provided at 40%, 60% and 75% of the voltage. The star point
contactors and run contactors shall be mechanically interlocked. The starter shall be complete with
timing relays. Where indicated, EOCR, earth fault and single phasing relays shall be provided.
Auto transformer starter shall consist of three contactors with current rating similar to the peak
current. All auto transformer shall be incorporated with thermal switch connected with control circuit.
14.4 Soft Starter
Soft Starter shall be a controller with 6 thyristors, which is used for the torque-control of soft starting
and soft stopping of three-phase squirrel cage induction motor.
The Soft Starter shall be housed in the respective MCC or Starter Panel Board. Adequate natural or
forced ventilation shall be ensured for continuous operations at the maximum specified 50 oC (122 oF)
ambient temperature. Harmful deposition of dust shall be excluded by suitable filters.
All Soft Starters shall be sized to drive the duty motors in a particular group to which it is designated.
The Power (kW) rating of the Soft Starters shall exceed the total driven load and shall make full
allowance for the following: -
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February 2007
Sec 1 - 12
Section 1 - Low Voltage Switchboard and Components Specification
14.4.1 Performance Functions
•
•
•
•
•
•
•
•
Constant Current Mode and Current Ramp Mode.
Constant control of the torque supplied to the motor during acceleration and deceleration
period.
Kickstart – shall provide “Extra Torque” at the beginning of a start (High Breakaway Torque)
but then accelerate freely with lower torque.
Bypass contactor - shall retain Motor Protection & Current Monitoring Features Function.
Wide frequency tolerance for generator set power supplies.
The starter shall be able to connect to the motor delta terminals in series with each winding.
Soft Stop – Shall be able to automatically monitors & extends motor deceleration time and will
provide optimum control of most application.
DC Braking – Greater Braking Torque shall be available for very high inertia loads by use of
“Soft Braking” technique.
14.4.2 Power Connection
•
•
•
3 wires Configuration
6 wires Configuration – Shall allow to control motors 50% larger than possible 3 wires
connection
Three phase voltage 230 V to 415 V50/60 Hz
14.4.3 Protection functions
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Built – in motor thermal protection
Processing of information from PTC thermal probes
Monitoring of the starting time
Motor preheating function
Protection against under loads and over current during continuous operation
Phase Imbalance – Sets the sensitivity of the “Phase Imbalance Protection”
Phase Sequence
Electronic Shearpin
Auxiliary Trip Input
Excess Start Time – Protect the Soft Starter from being operated outside its rated start capacity
Supply Frequency
Shorted SCR
Motor Connection
Serial Interface Failure
14.4.4 Sundry Features
•
•
•
•
•
•
IP42 or IP54 - 253 Amps and below
IP00
- 302 Amps and above
Current Read – out
Motor Temperatures Read – out
Trip Log (eight (8) position )
Multiple Function Sets
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February 2007
Sec 1 - 13
Section 1 - Low Voltage Switchboard and Components Specification
•
•
•
•
•
•
•
•
•
•
Restart Delay – sets the minimum time between the end of a stop and the beginning of the next
start
Pre-Start Tests – shall have self diagnostic test
Low current flag
High current flag
Motor Temperature Flag
Auto-Stop
Start Counter
Function Lock / Password Protection
Store / Restore Function Settings
Thermal Mode Override
14.4.5 Function Facilitating the Integration of Control System
•
•
•
•
•
Minimum shall consists of 4 logic inputs, 2 logic outputs, 3 relay outputs and 1 analogue
output.
Plug-in I/O connectors.
Function for configuration a second motor and easy to adapt settings
Display of electrical values, the state of the loads and the operating time.
RS 485 serial link for connection to Modbus.
14.4.6 Options
•
•
•
•
A remote terminal can be able to mount on the door of a wall – fixing or floor – standing
enclosure.
Advanced dialogue solutions such as power suite pocket PC with PPC type terminal and power
suite software workshop.
A range of wiring accessories for connection the starter to PLCs via a Modbus connection.
Bus communication and Ethernet, DeviceNet and Profibus DP network communication options.
14.5 Variable Speed Drive
Variable Speed Drives (AC Drives) shall utilise a standard AC Squirrel Cage Induction Motor
operating from a Variable Frequency Static Converter Speed Controllers. AC Drives shall operate in
proportion to a measured Analogue Signal (0-10 V & 4-20 mA).
The AC Drives shall be suitable for operation on a 380 – 500 Vac 3 Phase 50 Hz Power Supply with
minimum Supply Tolerance -15% to +10% and shall provide a 415 Volt 3 Phase Variable Frequency
Output suitable for driving a standard AC Squirrel Cage Induction Motors at high 50 oC (122 oF)
ambient temperatures.
The AC Drives shall be suitable for automatic control in response to 4-20mA Input Analogue Signal
and its frequency output of 0-50 Hz via 4-20 mA Analogue Signal shall be in proportion to this signal
range.
The AC Drives shall operate on Pulse Width Modulation (PWM) principle either with the Control
Method of Frequency Control (V/F) or Open Loop Vector Control (provide unequalled Motor Speed
and Torque Control at low speed).
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February 2007
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Section 1 - Low Voltage Switchboard and Components Specification
The current of the motor shall have a low content of harmonics to ensure high motor efficiency. Slip
compensation shall be provided so that the speed holding accuracy shall be better than +/- 0.5.
Each AC Drives shall be sized to drive all duty motors in a particular group to which it is designated.
The Power (kVA) rating of the AC Drives shall exceed the total driven load. Operating frequency
range 10 to 50 Hz.
For each process control, the application listed below shall be made available:•
•
•
•
•
•
•
Basic - Suitable for most purposes or applications.
Standard - Basic, with more programming possibilities.
Local / Remote Control - Two (2) external control plates.
Multi-Step Speed Control - Intended for switching between 16 preset fixed speeds.
PID Process Controller - Matching Pump/Fan speed to process requirements.
Multi-Purpose Control - Most flexible of all.
Pump and Fan Control - Control of up to five (5) pumps with Auto-Change. Can be used for
controlling one (1) AC drives and a total of four (4) auxiliary AC Drives. Can detect “Burst
Pipe” or “Loss Of Prime”. Full Motor Protection. Reduce Load Disturbance.
Shall have a built in Integrated AC Line Chokes (Reactors) to maximum protection and minimise any
main disturbances (harmonics) and Integrated EMC/Noise Filter compliant with immunity to fulfill
all EMC Immunity requirements. Emissions to EMC Class H complying with IEC61800-3 and shall
have built in Input Line Fuses – Fast Acting Semiconductor Fuses (for motor sizes 100 kW and
above) and Integrated Braking Chopper.
Shall allow for starting motors in cascade and assume starting current is not less than eight (8) times
the motor full load current (FLC) and suitable for Multi-Motor drive system.
Take account of Motor Power Factor and Efficiency with built in PFC with Autochange Function for
Centrifugal Pumps and Fans.
The Acceleration & Deceleration Time: 0 to 3,000 sec. The Relative Humidity: 0 to 95% RH: NonCondensing, Non-Corrosive, No Dripping Water. Shall allow for Constant Torque (Overload Factor:
1.5 x IH @ 50 oC) characteristics. High Starting Torque: > 200% (depending on motor and AC Drive
sizing) with Low Ripple in the Torque. High Starting Current: 2.0 x IH. Full Torque Control at all
speed all speed, including zero (0) speed or 0.0 Hz. The Torque Accuracy shall be less than 3%.
Where the AC Drives controls more than one (1) motor, a standby AC Drives shall be provided.
•
Drive and Motor Input and Output Circuit Protection:-
−
Overvoltage and undervoltage
Earth or ground fault,
Main Supervision (Single Phasing) - Trips if any input phase is missing
Motor Phase Supervision – Trip if any output cables/phase is missing
Drive Overtemperature
Overcurrent
Motor Phase Supervision
Motor Overload
Motor Stall
Short-Circuit of +24 V and +10 V Reference Voltages.
−
−
−
−
−
−
−
−
−
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February 2007
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Section 1 - Low Voltage Switchboard and Components Specification
−
Motor Underload - “Loss Of Prime” or “Belt Damage”, when the AC Drives has brought the
motor up to speed, an adjustable Underload Setting will detect the loss of load due to “Loss Of
Prime – Pump Application” or “Belt Damage – Fan Application”.
•
Common Spare Parts:-
−
Same Human Machine Interface (HMI) for all models.
Same Control Unit for all models.
−
•
•
•
•
•
•
•
•
•
•
•
Adjustable Switching Frequency – 1 to 16 kHz (Silent Motor Operation)
Removable / Detachable Keypad & Alphanumeric Display Unit (RS232C c/w 3 m cables)
mounted on the front side of panel door at approximately 1.5 m height from the floor.
Intelligent and easily configurable Multilingual Control Keypad and Display.
Inputs / Outputs (I/O) connections with simple quick connection terminal and Expandable
Inputs / Outputs (I/O) configuration.
All AC Drives are Constant Torque suitable for Pumps & Fans Application with PFC (Pump
Fan Control) Autochange Function.
Fixed Speed / Off / Variable Speed Switch for selection of control mode.
Panel mounted facility for local setting of frequency manually in the event of a failure of the
control signal.
Digital indication of output voltage.
Indication of output voltage.
Drives “Running / Failed” indicator.
Main Supply Isolating Switch.
The AC Drives unit shall include but not limited to the following protections: •
•
•
•
•
•
Phase to Phase and Phase to Ground (Earth) Short Circuit Protection.
Line Transient Protection.
Three (3) Phase Short Circuit Protection at output terminals.
Insensitive to incoming Power Phase Sequence.
Built-in Thermal Relay for excessive temperature and shall be reset manually.
Current Limiting feature.
Failure of the control signal shall stop the drive. Facilities shall be provided for indication of: •
•
•
Control signal failure alarm.
Variable frequency supply output failure alarm.
Variable frequency control unit failure alarm.
A summary Alarm Volt-Free Contact and five (5) Inputs / Outputs Card Slots shall be provided to
initiate an alarm to the SCADA System when any one or more of these alarms are on.
Diagnostic fault indicators and messages in Alphanumeric (plain English) shall also be provided.
The AC Drives shall be housed in the respective MCC or Starter Panel Board. Adequate natural or
forced ventilation shall be ensured for continuous operations at the maximum specified 50 oC (122 oF)
ambient temperature. Harmful deposition of dust shall be excluded by suitable filters.
Electrical Works Specifications
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February 2007
Sec 1 - 16
Section 1 - Low Voltage Switchboard and Components Specification
The driven motor frame size shall be selected to ensure that the motor will operate correctly without
overheating when fed from the Variable Frequency Drives (AC Drives) and operating over the speed
range of 10 to 50 Hz.
The AC Drives shall operate with an Input Power Factor not less than 0.95 throughout the speed
range.
Under any conditions of operation, the AC Drives shall not emit signals that may interface with Radio
Transmission or Operation. The AC Drives shall meet the requirements of EMC Class: H – IEC
61800-3 or higher regarding the emission of Radio Frequency Interference (RFI). Radio frequencies
emitted by other equipment according to EMC Class: H – IEC 61800-3 shall not hamper the correct
operation of the AC Drives.
The AC Drives shall not product Harmonics and Voltage Distortion that may affect the operation of
other equipment connected to the MCC or Starter Panel Board. Voltage and Current Distortions
produced by the AC Drives at the input side shall be limited to the values specified relevant
Standards, which are applicable for industrial distribution system.
14.6 Contactor for Motor Starters
All contactor starters shall incorporate air break or vacuum contactor rated for frequent duty in
accordance with IEC 60947-1 and IEC 60947-4-1. Contactor shall be rated to make and break
according to Category AC3 of IEC 60947-4-1. All contactors shall have the reference number on the
front of the contactor. All contactors shall be climate proof as standard. The rated impulse voltage
shall be at least 6 kV. The contactor AC3 current shall work up to 55oC ambient temperature without
derating. All contactors shall be finger safe as standard or with adaptable covers. The safety clearance
on the front of the contactor shall be less than 15 mm. The coil wire insulation shall be Class F. The
contactors shall be cadmium free and built with recyclable materials.
The Starters shall be incorporated to detect failure of any phase (single phasing or reverse polarity or
voltage and current unbalance) to interrupt the circuit when the contactor is de-energised. All starters
shall incorporate triple pole MCB. Overcurrent, Phase Sequence and earth leakage protection relays
shall be incorporated as later specified together with all necessary auxiliary relays, contactors, timers,
MCB, wiring and terminals. Controls system and indication facilities shall be provided on each
starter and incorporate with single pole MCB as specified.
All medium voltage starters shall incorporate a triple pole fully interlocked load breaking isolating
switch capable of breaking the stalled motor current and suitable for use on a 230/415 Volt, 50Hz, AC
system.
15.0 INDICATING LAMPS AND FITTINGS
The indicating lamp shall enclosed type and complies with IP40. The indication light size shall be 25
mm in diameter.
Lamps shall be easily removed and replaced from the front of the panel by manual means not
requiring the use of extractors. The lamps shall be cluster LED type and fitted into an accepted
standard form of lamp holder. The rated lamp voltage shall be 24 V DC/1A (resistive).
Electrical Works Specifications
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February 2007
Sec 1 - 17
Section 1 - Low Voltage Switchboard and Components Specification
The bezels of metal or other approved material holding the lens shall be of an approved finish and
easily removed from the body of the fittings so as to permit access to the lamp and lens. The lens shall
be in standard colours, red, green, blue, white and amber. The colour shall be in the lens and not an
applied coating and the different coloured lens shall be fully interchangeable. The lens holder shall
incorporates a reflector ideally designed to eliminate light loss and marking plate serves as a filter to
diffuse the light effectively, ensuring a clear illumination face.
The service life at nominal voltage and at an ambient temperature of 25oC shall be 100,000 hours.
Indicating lamps fitted to the facias of switch and instrument cubicles or panels shall be adequately
ventilated.
Refer to Appendix H - Meaning of Colours from IEC 60073 and IEC 60204-1.
16.0 PUSH BUTTONS
All stop push buttons whether forming part of a switchboard or supplied as a separate control station,
shall be of the stay-put pattern arranged to permanently open a circuit until deliberate reset action has
been carried out.
All emergency push buttons shall have red mushroom headed pushes of the stay-put pattern, shall be
connected in control circuits such that they are effective under all conditions and shall be positioned
in the immediate vicinity of the associated pump motor.
The start push buttons shall be effective only in selected circuits, primarily hand control circuits only.
Emergency push buttons located next to equipment (outdoor) shall be of weather proof type.
17.0 ANTI-CONDENSATION HEATERS
A thermostatically controlled anti-condensation heater shall be provided at the back of the floor
mounted switchboards and starter boards together with an over-riding rotary isolating switch. As a
general rule the heaters shall be placed in a separate compartment at the bottom in such a way that the
viscosity of oil in any dashpot is not affected and the thermostats shall be adjustable over the range of
at least 21 °C to 50 °C.
The heaters shall operate at 230 volts and the supply is therefore to be taken from one phase and
neutral of 415 Volt system.
18.0 LABELS
Internally fitted labels shall be finished white engraved letters and numbers filled with black
laminated material such as Traffolyte may be used on rear engraved and filled plastic.
Externally fitted labels shall be of perspex or other approved transparent plastic with letters and
numbers rear engraved and filled with black. The back surface of each label shall be finished with a
first coat of aluminium paint and a second coat of paint of the same colour as the panel external
finish.
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February 2007
Sec 1 - 18
Section 1 - Low Voltage Switchboard and Components Specification
19.0 PADLOCKS
Padlocks and keys shall be minimum of the Yale type in an incorrodible metal.
20.0 CABLE ENTRIES
All switchboards, starter panels and TNB meter panel shall unless otherwise specified, shall have
cables glanded at bottom entry of the switchboard. Removable glands plates shall be mounted at least
300 mm above the base of the panels. If gland plates are provided inside the switchboards/starter
panel cubicle entries in the base of the cubicle shall be made dust-proof in an approved manner.
Refer to Appendix I – Switchboard Plinth and Cable Trench Design Drawing.
21.0 JUNCTION BOX
The junction box or enclosures shall be IP66, dust/damp proof according to IEC 529. It shall be with
high mechanical impact up to 55 N/mm2. It shall good resistance to UV radiation. Able to withstand
temperature range up to 75°C.
It shall resistance to chemical, detergent solvent, grease and oil. It shall also non-hygroscopic (does
not absorb moisture) type. Can be made of high quality thermoplastic (industrial grade), ABS
thermoplastic or polyurethane. All the cable entries are must from bottom and enclosed with
watertight coupler. The gasket piece used must from polyurethane for a continuous seal to maximise
the IP rating. The junction boxes shall be watertight surface mounting type. The screws used shall be
type self-tight screws and made of the same material as the box.
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February 2007
Sec 1 - 19
Appendix A - Metal Treatment and Painting Procedures (Electro-Galvarnised Metal Sheets)
Appendix A
Metal Treatment and Painting
Procedures (Electro-Galvarnised
Metal Sheets)
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1: Appendix A – Metal Treatment and Painting Procedures (Electro-Galvarnised Metal Sheets)
APPENDIX A
A-2 ELECTRO-GALVANISED METAL SHEETS
PROCESS 1
Metal parts are soaked in alkaline degreaser
TANK 1 (ALKALINE DEGREASER)
Chemical
Dilution
Chemical Required
Methods
Time
Tank Material
: SPU 8 - 30 Alkaline Liquid Degreaser
: 1: 5 parts of water
: 140 litres
: Immersion
: 15 - 30 minutes
: Stainless Steel 316
PROCESS 2
Water spray gun - To clean the alkaline residue
PROCESS 3
The metal treated should be left for air dry prior for powder coating
PAINTING PROCESS
- Selection of color of epoxy powder paint and filled up in the spray tank.
- Parts are hung up in the spray booth
- The parts are electrostatically sprayed with the epoxy powder paint.
- Sprayed parts are removed from the booth and placed in an infrared oven.
- Parts are then baked in the oven at 180 degree Celsius for a minimum of 30 minutes
- Cured parts are then removed from oven.
Quality Checks: - Painted parts are checked for the quality of paint.
- Dry film thickness are checked with an elcometer
- Dry film thickness should be a minimum of 45 micron as standard. Dry film thickness of
60 - 80 microns are non standard and available on request.
- Rejected parts are to be reworked.
Electrical Works Specifications
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February 2007
App: A - 1
Appendix B - Floor Mounted Switchboard Compartment Dimensions
Appendix B
Floor Mounted Switchboard
Compartment Dimensions
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1: Appendix B - Floor Mounted Switchboard Compartment Dimensions
APPENDIX B
Up to 100 Amps (MCCB)
More Than 100 Amps and Up
To 400 Amps (MCCB)
Incoming : 450 mm
Incoming : 550 mm
Subsequent Compartment :
450 mm
Subsequent Compartment : 500
mm
(Until last compartment)
Cable Compartment : Behind
Cable compartment : Behind
Cables shall be glanded at
bottom entry of the
switchboard
Cables shall be glanded at
bottom entry of the switchboard
400 Amps and Above
2 panels : 1. MSB
2. MCC
MSB
MCC
Incoming :
600 mm
Subsequent
compartment :
450 mm
Subsequent
compartment :
450 or 500 mm
Cables shall be glanded at
bottom entry of the switchboard
Floor Mounted Switchboard Compartment Dimensions
Electrical Works Specifications
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February 2007
App: B - 1
Appendix C - Typical Switchboard Drawings (Floor Mounted, Wall Mounted and Outdoor Type)
Appendix C
Typical Switchboard Drawings
(Floor Mounted, Wall Mounted and
Outdoor Type)
Electrical Works Specifications
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February 2007
Electrical Works Specifications
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App: C - 1
Electrical Works Specifications
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App: C - 2
Electrical Works Specifications
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App: C - 3
Electrical Works Specifications
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App: C - 4
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App: C - 5
Electrical Works Specifications
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App: C - 6
A/T
30A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB1
A/T
A/T
30A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB2
30A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB12
RYB3
A/T
RYB4
30A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB5
60A TPN
MCCB 25KA
4-6MM x 25MM TINNED
CU. BUSBAR (RYBN)
A/T
30A TPN
MCCB 10KA
(HANDLE
LOCK)
R
Y
DOL
30A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB6
B
RYB7
RYB3
RYB2
RYB1
20A TP
MCCB
15A TP
MCCB
20A TP
SWITCHING
CONTACTOR
T/H
ON/OFF
SWITCH
PH
ON/OFF
SWITCH
20A TP
MCCB
20A TP
MCCB
20A TP
SWITCHING
CONTACTOR
R
R
R
R
5 KVAR
CAP. BANK
10 KVAR
CAP. BANK
10 KVAR
CAP. BANK
10 KVAR
CAP. BANK
4 STEP CAPACITOR BANK PANEL
SINGLE LINE DIAGRAM
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
16A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB10
RYB11
3x6A 1P
MCB
PH. SEQ. RELAY
6A 1P
MCB
3x6A 1P
MCB
PF
2xEXHAUST FAN
60A TPN
MCCB 25KA
6A 1P
MCB
3X100/5A
CL.3 5VA CT
1-100/5A
CL.1 15VA CT
AS
100/5A
ZCT
ELR
S/T COIL
6A 1P MCB
32A
2POLE
MCB
R13
PSR
TO CONTROL
VS
N
RYB4
20A TP
SWITCHING
CONTACTOR
DOL
16A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB9
PANEL
HEATER
N
20A TP
SWITCHING
CONTACTOR
DOL
16A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB8
60W
N
3X6A MCB
PFR
&PF
DOL
16A TPN
MCCB 10KA
(HANDLE
LOCK)
UUU
A/T
V
0-500V
R
Y
A
0-100A
3x60A FUSE+N
B
SURGE PROTECTOR
100A 4P
MCCB 50KA
(HANDLE LOCK)
FOR 200A AND
ABOVE IDMT, OC / EF
SHALL BE USED
App: C - 7
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 8
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 9
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 10
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 11
A/T
RYB1
30A TPN
MCCB 10KA
5MM X 25MM TINNED
CU. BUSBAR (RYBN)
30A TPN
MCCB 10KA
(HANDLE LOCK)
R
Y
B
30A 2P
MCCB 10KA
(HANDLE LOCK)
R7
RYB5
60W
N
PANEL
HEATER
3X6A MCB
PFR
&PF
15A TPN
MCCB 10KA
(HANDLE LOCK)
15A TPN
MCCB 10KA
(HANDLE LOCK)
RYB4
RYB3
RYB2
DOL
DOL
30A TPN
MCCB 10KA
(HANDLE LOCK)
30A TPN
MCCB 10KA
(HANDLE LOCK)
RYB6
6A 1P
MCB
T/H
3x6A 1P
MCB
PH. SEQ. RELAY
UUU
A/T
A/T
PSR
ON/OFF
SWITCH
3x6A 1P
MCB
TO CONTROL
VS
N
V
0-500V
R
Y
A
0-60A
PH
RYB1
RYB2
RYB3
RYB4
PF
10A TP
MCB
10A TP
MCB
10A TP
MCB
10A TP
MCB
20A TP
SWITCHING
CONTACTOR
20A TP
SWITCHING
CONTACTOR
20A TP
SWITCHING
CONTACTOR
20A TP
SWITCHING
CONTACTOR
EXHAUST FAN
R
R
R
R
2 KVAR
CAP. BANK
3 KVAR
CAP. BANK
3 KVAR
CAP. BANK
3 KVAR
CAP. BANK
3X60/5A
CL.3 5VA CT
1-60/5A
CL.1 15VA CT
AS
RCCB
B
63/0.3A
4P RCCB
60A 4P
MCCB 25KA
(HANDLE LOCK)
4 STEP CAPACITOR BANK PANEL
SINGLE LINE DIAGRAM
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 12
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 13
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 14
S/D
20A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB1
S/D
S/D
20A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB2
20A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB12
RYB3
A/T
RYB4
30A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB5
200A TPN
MCCB 35KA
4-6MM x 50MM TINNED
CU. BUSBAR (RYBN)
A/T
20A TPN
MCCB 10KA
(HANDLE
LOCK)
R
Y
S/S
30A TPN
MCCB 10KA
(HANDLE
LOCK)
RYB6
B
RYB7
RYB1
RYB2
RYB3
T/H
ON/OFF
SWITCH
MCCB
TO SUIT
DESIGN STEP
MCCB
TO SUIT
DESIGN STEP
TO SUIT
DESIGN STEP
(SWITCHING
CONTACTOR)
TO SUIT
DESIGN STEP
(SWITCHING
CONTACTOR)
TO SUIT
DESIGN STEP
(SWITCHING
CONTACTOR)
TO SUIT
DESIGN STEP
(SWITCHING
CONTACTOR)
R
R
CAP. BANK
CAP. BANK
R
CAP. BANK
R
CAP. BANK
200A TPN
MCCB 35KA
(HANDLE
LOCK)
RYB10
PH
ON/OFF
SWITCH
100A TPN
MCCB 25KA
RYB11
6A 1P
MCB
3x6A 1P
MCB
PH. SEQ. RELAY
6A 1P
MCB
3x6A 1P
MCB
30A 2P
MCCB 10KA
(HANDLE
LOCK)
R13
PSR
TO CONTROL
N
PF
N
MCCB
TO SUIT
DESIGN STEP
VSD
200A TPN
MCCB 35KA
(HANDLE
LOCK)
RYB9
PANEL
HEATER
RYB4-6
MCCB
TO SUIT
DESIGN STEP
VSD
60A TPN
MCCB 25KA
(HANDLE
LOCK)
RYB8
60W
N
3X6A MCB
PFR
&PF
S/S
60A TPN
MCCB 25KA
(HANDLE
LOCK)
UUU
S/D
R
Y
B
1-100/5A
CL.1 15VA CT
6A MCB
2 x EXHAUST FAN
3X400/5A
CL.3 5VA CT
DPM
4-400/5A
CL.10P10
15VA CTS 3x60A FUSE+N
IDMT
EF/OC
S/T COIL
6A 1P MCB
SURGE PROTECTOR
400A 4P
MCCB 50KA
(HANDLE LOCK)
6 STEP CAPACITOR BANK PANEL
SINGLE LINE DIAGRAM
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: C - 15
Appendix D - Digital Protective Relay Standards
Appendix D
Digital Protective Relay Standards
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1: Appendix D - Digital Protective Relay Standards
APPENDIX D – DIGITAL PROTECTIVE RELAY STANDARDS
Requirements
Protection relays
Electro Magnetic
Emission tests
Compatibility (EMC) Disturbing field emission
Conducted field emission
Immunity tests
Radiated disturbances
– radiated fields
– electrostatic discharge
– to power magnetic fields at network
frequency
Conducted disturbances
– RF disturbances
– fast transient bursts
– damped oscillating waves
– surges
– voltage interruptions
Environmental
Mechanical
constraints
Safety
Climatic conditions
In operation
– vibrations
– shocks
– earthquakes
De-energised
– vibrations
– shocks
– jolts
Enclosure tests
– Mechanical protection degree
– Fire withstand
Electrical tests
– earth continuity
– 1.2/50µs impulse wave
– dielectric at network frequency
In operation
– to cold
– to dry heat
– to damp heat
– salt mist
– corrosion influence/Gas test
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Standards
IEC 60255
IEC 60255-25
EN 55022
IEC 60255-25/EN 55022
Level
A
IEC 60255-22-3
IEC 61000-4-3
ANSI C37.90.2
IEC 60255-22-2, ANSI
C37.90.3
IEC 61000-4-8
III
IEC 60255-22-6
IEC 60255-22-4
IEC 61000-4-4
ANSI C37.90.1
IEC 60255-22-1, ANSI
C37.90.1
IEC 61000-4-5
IEC 60255-11
III
A and B
IV
IEC 60255-21-1
IEC 61000-2-6
IEC 60255-21-2
IEC 60255-21-3
2
Fc
2
2
IEC 60255-21-2
IEC 60255-21-2
IEC 60255-21-2
2
2
2
IEC 60529
NEMA
IEC 60695-2-11
IP52
Type 12
4
III
IEC 61131-2
IEC 60255-5
IEC60255-5, ANSI
C37.90
IEC 61068-2-1
IEC 61068-2-2
IEC 61068-2-78
IEC 61068-2-52
IEC 61068-2-60
Ad
Bd
Cab
Kb/2
App: D - 1
Section 1: Appendix D - Digital Protective Relay Standards
In storage
– temperature variation
– to cold
– to dry heat
– to damp heat
Requirements
Certification (*)
CE
UL
CSA
GOST
Low Voltage
electrical installations
Functional Safety of
electronic safety
related systems
Communication
Data transmission industrial protocol:
Modbus RTU
Between protective relay and control
system inside a power station
For power substation automation
inside the substation
IEC 61068-2-14
IEC 61068-2-1
IEC 61068-2-2
IEC 61068-2-78
IEC 61068-2-30
Standards
EN 50263 Harmonised
Standard European
Directive
UL508
CSA C22.2
IEC 60364
Nb
Ab
Bb
Cab
Db
Level
IEC61508
IEC 61158 Field Bus
Foundation
EC 870-5 series and
IEC 870-5-103 – DNP3
IEC 61850
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: D - 2
Appendix E - Digital Protective Relay Operating Conditions
Appendix E
Digital Protective Relay Operating
Conditions
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1: Appendix E - Digital Protective Relay Operating Conditions
APPENDIX E – DIGITAL PROTECTIVE RELAY OPERATING
CONDITIONS
Temperature:
- 25°C to +70°C
External auxiliary power supply:
- For Low and Mid-end solutions/
applications
- For High-end
solutions/applications:
From AC/AC UPS system or dual battery charger
24V-250V DC and 110V-240V AC (50Hz/60Hz)
24V-250V DC
Current sensors:
Voltage sensors:
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
In/1A or In/5A current transformers, Core Balance CT’s or
interposing ring CT
100V, 110V, 100V/ √3, 110V/√3 and voltages as per IEC 60
255-6
App: E - 1
Appendix F - Digital Protective Relay Metering Functions
Appendix F
Digital Protective Relay Metering
Functions
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1: Appendix F - Digital Protective Relay Metering Functions
APPENDIX F – DIGITAL PROTECTIVE RELAY METERING
FUNCTIONS
Designation
Low-end solutions /
Applications
Current or Voltage
Phase current I1, I2, I3 RMS
Calculated residual current I0Σ
Demand current I1, I2, I3
Peak demand current IM1, IM2, IM3
„
„
„
„
Mid-end
solutions/
Applications
„
„
„
„
Measured residual current I0, I’0
Voltage U21, U32, U13, V1, V2, V3
Residual voltage V0
Positive sequence voltage Vd/rotation direction
Negative sequence voltage Vi
Frequency
„
„
„
„
Active power P, P1, P2, P3
Reactive power Q, Q1, Q2, Q3
Apparent power S, S1, S2, S3
Peak demand power PM, QM
Power factor
„
„
„
„
„ (P)
„ (Q)
„ (S)
Calculated active and reactive
energy(±Wh,±VAR)
„
Active and reactive energy by pulse counting
(±Wh,±VAR)
„
Temperature
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
„
„
App: F - 1
Appendix G - Digital Protective Relay Network, Machine and Switchgear Diagnosis
Appendix G
Digital Protective Relay Network,
Machine and Switchgear
Diagnosis
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1: Appendix G - Digital Protective Relay Network, Machine and Switchgear Diagnosis
APPENDIX G – DIGITAL PROTECTIVE RELAY NETWORK,
MACHINE AND SWITCHGEAR DIAGNOSIS
Low-end solutions /
Applications
Mid-end solutions/
Applications
CT/VT supervision – ANSI 60/60FL
„
„
Trip circuit supervision – ANSI 74
„
„
Cumulative breaking current
„
„
Number of operations, operating time, charging
time, number of racking out operations
„
„
„
„
„
„
„
„
Designation
Switchgear Diagnosis
Auxiliary power supply monitoring
Network and Machine Diagnosis
Tripping context
Tripping current Trip I1, I2, I3, I0
Phase fault and earth fault trip counters
Unbalance ratio / negative sequence current Ii
Phase displacement φ0, φ’0, φ0 Σ
Phase displacement φ1, φ2, φ3
„
Disturbance recording
„
„
Thermal capacity used
„
„
Remaining operating time before overload
tripping
Waiting time after overload tripping
„
„
„
„
„
Running hours counter / operating time
Starting current and time
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
„
„
App: G - 1
Section 1: Appendix G - Digital Protective Relay Network, Machine and Switchgear Diagnosis
Designation
Start inhibit time
Number of starts before inhibition
Unbalance ratio / negative sequence I’i
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Low-end solutions /
Applications
Mid-end solutions/
Applications
„
„
„
„
„
App: G - 2
Appendix H - Meaning of Colours from IEC 60073 and IEC 60204-1
Appendix H
Meaning of Colours from IEC 60073
and IEC 60204-1
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 1: Appendix H - Meaning of Colours from IEC 60073 and IEC 60204-1
APPENDIX H
COLOURS
MEANING
EXPLANATION
ACTION BY OPERATOR
Red
Emergency
Hazardous condition
Immediate action to deal with
hazardous condition (e.g. by
operating emergency stop)
Yellow
Abnormal
Abnormal condition impending
critical condition
Monitoring and/or intervention
(e.g. by re-establishing the
intended function)
Green
Normal
Normal condition
Optional
Blue
Mandatory
Indication of a condition that
requires action by the operator
Mandatory action
Neutral
Other conditions; may be used
whenever doubt exists about
application of Red, Yellow,
Green & Blue
Monitoring
White
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: H - 1
Appendix I – Switchboard Plinth and Cable Trench Design Drawing
Appendix I
Switchboard Plinth and Cable
Trench Design Drawing
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
2100mm
SWITCHBOARD
CABLE GLAND
1000mm
WALL
GLAND PLATE
1000mm
WALL
200mm
PLINTH
CABLE TRENCH
CABLE
SPECIFICATION AND DESIGN OF
SWITCHBOARD PLINTH AND CABLE
TRENCH
-
-
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: I - 1
Section 3 - Standby Generator Specification
Section 2
Standby Generator Specification
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 2 – Standby Generator Specification
Page
Section 2 - Standby Generator Specification
1.0
General
2-1
2.0
Engine
2-1
3.0
Lubrication System
2-1
4.0
Exhaust Fan
2-1
5.0
Radiator Air Discharge
2-2
6.0
Fuel System
2-2
7.0
Engine Governing
2-2
8.0
Engine Instrumentation
2-2
9.0
Alternator And Exciter
2-3
10.0
Voltage Regulation
2-3
11.0
Voltage Waveform
2-3
12.0
Starting System
2-3
13.0
Fuel Supply System
2-4
13.1
Fuel Tank
2-4
13.2
Fuel Transfer System
2-4
13.3
Fuel Supply Piping
2-5
14.0
Protective Devices
2-5
15.0
Control Panel
2-6
16.0
Automatic Mains Failure (AMF) Switchboard
2-6
17.0
Changeover Contactor
2-8
18.0
Earthing System
2-9
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
i
Section 2 - Standby Generator Specification
SECTION 2 - STANDBY GENERATOR SPECIFICATION
1.0 GENERAL
This section describes the specification of diesel generator set. The set shall comprise a diesel engine
directly coupled to a 3 phase alternator with auxiliary equipment as further described below and shall
be capable of maintaining a continuous output of not less than the kVA specified at 0.8 lagging power
factor, 415 volts, 3 phase, 4 wire, 50 Hz supply. Under the operating conditions specified hereafter
and within a guaranteed range of frequency and voltage fluctuations after making full allowance for
all internal losses and power consumed by ancillaries.
The operating conditions shall be:•
•
•
Total baromatic pressure
Air temperature
Relative humidity
: 750 mm Hg.
: 40 °C
: 95%
2.0 ENGINE
The engine shall be multi cylinder, vee/in line configuration, 2/4 stroke, naturally aspirated/turbo
charged, air-cooled or water cooled with fan and radiator, instant starting and in general compliance
with BS 5514 as minimum requirements. Engine speed shall be 1500 rpm. and capable of producing
continuously the service power not less than that required by the alternator for the generation of the
required output under the specified operating conditions. The engine shall be able to withstand an
overload of 10% for 1 hour in any period of 12 hours consecutive running.
Engine base mounting shall be fabricated steel channel base frame complete with spring type
vibration damper.
3.0 LUBRICATION SYSTEM
The engine shall be complete with enclosed force-feed lubricating system by gear type oil pump with
full flow replaceable paper element type oil filter. Oil pan shall be of the sump type.
4.0 EXHAUST FAN
The engine shall be provided with a suitable exhaust system capable of carrying exhaust gases from
the engine and dissipate them to the atmosphere as quickly and silently as possible. The piping and
fitting shall have minimum thickness of 3 mm and shall be suitably protected from corrosion by
application of heat resistant paint.
A suitable flexible connection shall be made between the section of piping fixed to the engine and the
piping fixed to the building structure.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 2 - 1
Section 2 - Standby Generator Specification
The exhaust system shall incorporate an efficient residential type silencer of the absorption-type
capable of reducing the exhaust noises of the engine to an acceptable level. Exhaust piping inside the
Generator Room shall be fully lagged with minimum 20 mm thick asbestos rope that in turn sheathed
with tinfoil. Silencer shall be lagged with minimum 35 mm thick fibre glass section. A metal thimble
guard shall be installed where the exhaust pipe passes through the wall.
5.0 RADIATOR AIR DISCHARGE
Unless otherwise dictated by room design, engine radiator discharge air shall be directed outdoors
through an approved discharged duct that connects the engine radiator to an opening in an external
wall. The duct shall be as short as possible. A length of flexible duct shall be provided between the
radiator and the fixed air discharge duct.
Shall provide an aluminium automatic self-opening and self-closing shutter complete with aluminium
frame to be mounted on the wall opening. The automatic shutter shall be self-closing when the engine
is not in operation. When the engine starts the shutter shall be opened outwards by air discharged
from the radiator. The automatic shutter system shall be so designed as to keep the noise level to a
minimum. In the case of an air cooled engine, air discharge ducting system complete with aluminium
automatic shutter as above shall be provided.
6.0 FUEL SYSTEM
The engine shall be capable of operating on 'Class A' fuel to BS 2869. The fuel pump shall be of the
gear type complete with governor and throttle and capable of fuel delivery to injectors under all
power conditions of the engine. The pump shall be self- adjusting for wear and fuel viscosity. Fuel
filter shall be of heavy duty, replaceable and paper element type.
7.0 ENGINE GOVERNING
The governing accuracy of the engine shall be in accordance with BS 5514 part 4, 'Class A1'. The
speed droop shall be less than 5%.
8.0 ENGINE INSTRUMENTATION
The instruments and gauges shall be flush mounted on the metal clad panel and shall include but not
limited to the following: •
•
•
•
Elapsed hours running meter
Lubricating oil pressure gauge
Cooling water temperature gauge
Tachometer
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 2 - 2
Section 2 - Standby Generator Specification
9.0 ALTERNATOR AND EXCITER
The alternators shall be of screen protected, drip-proof, revolving fields, brushless, salient pole type,
directly coupled to the engine and fitted with an exciter to comply in all respects to BS 4999 and BS
5000. Insulation shall conform to BS 2757 Class 'F'. The rotor or armature shall be of one piece, four
pole type with lamination pressed and keyed to the shaft. The stator shall be of the multiplicity type
for high or low voltages in 'Star' or 'Delta' connections. Damper windings shall be provided in the
pole faces. The alternator of brushless type shall be continuously rated not less than the
manufacturer's rated kVA specified at 0.8 power factor lagging when wound for 415 volts, 3 phase, 4
wire, 50 Hz supply.
10.0 VOLTAGE REGULATION
The voltage regulation shall be of solid state transistor amplified type capable of providing voltage
regulation Grade VR 2.21 of BS 4999 part 40. The alternator, when driven its rated speed and
operating with its normal excitation control system, shall be capable of maintaining the voltage under
steady state conditions within + 2.5% of rated voltage for all loads between no-load and rated load at
rated power factors. Following transient changes the voltage shall restored to within these limits in
less than 10 seconds. When alternator, driven at rated speed and giving its rated voltage on no load
under its normal excitation control system is switched on to a symmetrical load which would absorb
60% of rated current at rated voltage at a power factor between 0.4 and zero lagging, the initial
voltage drop shall be limited to 15% of rated voltage and the voltage shall recover to at least 97% of
rated voltage in less than 1.5 seconds. The transient rise in voltage after a sudden rated load rejection
at rated power factor and constant speed shall not exceed 20%. Normal voltage shall be variable by
means of voltage trimmer within +5% of rated voltage.
11.0 VOLTAGE WAVEFORM
The voltage waveform shall approximate closely to a sine wave both at no load and full load with a
lagging power factor of 0.8 and shall not exceed the limits as stated in BS 4999 part 40.
12.0 STARTING SYSTEM
Each engine shall be fitted with electric starting system with a 24 volt heavy duty nickel cadmium
battery of sufficient capacity to provide a minimum of six (6) successive abortive starts of the engine
without recharging. The minimum cranking period for each abortive starts shall be 15 seconds. The
battery shall be connected to the starter motor starting and stopping circuit complete with indicating
or signal devices. Capacity of the nickel cadmium battery shall be as recommended by the battery
manufacturer for particular make and model of the generator set that required to operate the dc
indicating, tripping and control circuits.
Battery shall be housed in a rack or crate located beside the generator set and covered on top by a
removable wooden cover with sufficient ventilation. The battery charger shall be of automatic
constant potential type with two rates of charging complete with ammeters, voltmeters, main
isolators, indicating lights for `Mains On', `Trickle Charge', `Boost Charge', `AC Failure' and etc.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 2 - 3
Section 2 - Standby Generator Specification
It shall employ fixed resistance charging and transistor switched relay to switch in the boost charge
resistor when the battery voltage falls below a predetermined level recommended by the battery
manufacturer. After the boost period, the relay shall be de-energised automatically and the circuit
reverts to trickle charge condition. A milliammeter and an ammeter of suitable range shall be
provided to indicate trickle and boost charge currents respectively. The battery charger shall be
incorporated in the generator switchboard.
The starter motor for the engine shall be automatic type to be controlled by the automatic starting and
stopping system. In the event of more than one generator sets are installed then each engine shall be
provided with its own nickel cadmium battery and battery charger as above.
13.0 FUEL SUPPLY SYSTEM
13.1 Fuel Tank
A fuel tank having a capacity for a minimum of 8 hours continuous operation at full load or 1,000
litres capacity whichever is larger supported by suitable angle irons to permit gravity feed to the
engine pumps. The fuel tank shall be fabricated from 2.5 mm thick mild steel sheet construction, not
galvanised but painted inside and outside with oil resistant prime and externally finished with
undercoat and topcoat. A dial type level indicator calibrated in litres shall be provided.
A breather is to be provided. The breather opening must be adequate to vent gases and air from the
fuel tank without back pressure.
The fuel pump suction line shall pick fuel about 30 mm from the bottom of the fuel tank complete
with fuel strainer. The fuel return line shall be so located so as to allow separation of the fuel and
vapour or gases in the expansion space above the normal fuel level and shall be pointed away from
the breather and suction area.
A drain valve complete with padlock shall be provided at a low point in the fuel tank in an accessible
location to allow periodic removal of water condensation and sediment.
If more than one generator sets are installed in the Generator Room, a common fuel tank may be used
unless otherwise specified. However, the common fuel tank shall be off sufficient capacity, or
otherwise specified elsewhere, to run the generator sets simultaneously for a minimum of 8 hours
continuous operation at full load. Shall supply a full tank of fuel at the time of handing over. Fuel
required to carry out all tests including work test and site tests shall be supplied and shall be
additional to the full tank of fuel mentioned above.
13.2 Fuel Transfer System
Fuel transfer system for transferring fuel from drums into the fuel tank shall be supplied and installed.
The fuel transfer system shall consist of hand operated pump installed in parallel with an electric
motor-driven pump.
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February 2007
Sec 2 - 4
Section 2 - Standby Generator Specification
A filler pipe shall be installed from the inlet point of the fuel tank to the outlet point of the fuel
transfer pumps. A suitable length of flexible transparent oil resistant hose shall be connected from the
inlet of the fuel pumps for off-loading from drums.
The fuel transfer pumps shall be installed as close to the fuel tank as possible. The electric motor
driven pump shall be of the self-priming type and shall have sufficient suction lift to deliver a transfer
rate of 50 litres per minute. The electric motor driven pump shall be suitable for operation from single
phase, 230 V, 50 Hz supply.
To carry out wiring in galvanised steel conduit from the electric starter point on nearby wall to the
electric motor-driven pump.
13.3 Fuel Supply Piping
Fuel piping and plumbing shall be of black iron pipe or 'steam' pipe. The diameter of the pipe shall be
as recommended by the generator set supplier. Seamless synthetic rubber flexible hose shall be used
for connection to the engine fuel inlet and return outlet. Must keep the number of bends to a
minimum. Feeding fuel pipe from the fuel tank shall be with a shut-off valve near the fuel tanks for
maintenance purposes. Facilities shall be provided to padlock the shut-off valves in open position.
Overflowing fuel from the engine shall be fed back to the fuel tank by means of fuel pipe complete
with check valve near the fuel tank. Keys alike shall be provided for the padlocks used for shut-off
valves of the fuel feeding pipe and the padlocks used for drain valves of the fuel tank. Fuel pipes
where required to be distinguished from pipelines of other services shall be brown as a basic
identification colour in compliance with BS 1710.
14.0 PROTECTIVE DEVICES
The generator set shall be provided with protective devices to provide warning and automatic
shutdown under the following conditions: •
•
•
•
•
•
Low oil pressure - warning and trip
High jacket water temperature - warning and trip
Fail to start - warning and trip
Over speed - trip
Low fuel level (1st.stage) - warning
Low fuel level (2nd.stage) - trip
The low oil pressure warning and shut-down and the high jacket water temperature warning and shutdown protective devices shall be set at the manufacturer's recommended pressures and temperature
respectively. The overspeed shutdown protective devices shall also be set at the speed recommended
by the manufacturer. The `failure to start' warning and shut-down protective devices shall operate if
the engine should fail to start within a adjustable pre-set time and stop the automatic starting cycle to
avoid successive depletion of the battery charge. The time shall be set to allow for 6 attempts in
starting each with a rest interval of half the time setting of the attempt to start. Under any of the above
conditions, a common alarm bell of 250 mm diameter installed at the control panel shall sound.
In addition, indication lamps showing operation of each engine protective devices shall also be
provided. Shall arrange for simulation tests of the above on completion of the generator set erection.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 2 - 5
Section 2 - Standby Generator Specification
15.0 CONTROL PANEL
A generator set control panel housing control switches and buttons, relays, timers, indicating lights,
indicating instruments, selector switches, alarms and etc. shall be supplied and installed.
The control panel shall be cubicle construction suitable for floor standing. All control wiring shall be
properly labelled with number sleeves.
The following facilities shall be incorporated as minimum requirements: •
•
•
•
Indication lamps showing operation of each engine protective devices
A lamp test button
Alarm bell indicating operation of each engine protective devices with `Alarm Silence' button
Selector switch giving `Auto', `Test', `Off', and `Manual', operation modes. The function of
each mode is as follows:-
-
‘Auto’ mode
‘Test’ mode
-
-
‘Off’ mode
-
-
‘Manual’ mode
-
•
A timer (t1) adjustable up to 15 seconds for starting the generator set; a timer (t2) adjustable up
to 60 seconds for load connection to the generator set after starting up the generator set; a timer
(t3) adjustable up to 5 minutes before the automatic changeover contactor changes to TNB
supply after a mains failure; a timer (t4) adjustable up to 10 minutes for shutting down the
generator set after load connection to TNB supply on restoration of TNB supply. All timers
shall have calibrated scales in seconds or minutes as appropriate complete with an adjustable
knob and pointer.
`Start' and `Stop' push buttons
Self-latching mushroom head type 'Emergency Stop' button (One to be provided at the control
panel and another one in the vicinity of the generator set to be decided on site)
•
•
This places the generator set in its normal standby mode
To test the auto-start by simulating TNB power failure
without actually changing over the load from the TNB supply to the
generator set. However if TNB supply fails during `Test' mode, load
connection to the generator set must operate.
To cut out the starting circuit so that the engine cannot
be started.
To permit manual operation of the generator set.
16.0 AUTOMATIC MAINS FAILURE (AMF) SWITCHBOARD
The generator switchboards shall be of the self-contained cubicle type, free standing floor mounted,
metalclad, flush fronted suitable for front and rear access housing switchgear and controlgear,
protective relays, meters, indicating lamps, cable terminating boxes, and all other necessary items of
equipment. Whether specified hereinafter or on the drawings or not it shall be suitable for operation
on a 415/230 V, 3 phase, 4 wire, 50 Hz system with solidly earthed.
Unless otherwise specified elsewhere, the generator switchboards shall be in general compliance with
BS 5486 Part 1 and capable of withstanding without damage fault condition of not less than 31 MVA
at 415 volts for 1 second.
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Issue 01 / Revision 01
February 2007
Sec 2 - 6
Section 2 - Standby Generator Specification
The framework of the switchboard shall be fabricated from rolled steel sections and shall be selfsupporting when assembled, uniform in height and depth from front to back. The rigid construction
shall be designed to withstand without any sag, deformation or warping, the loads likely to be
experienced during normal operating, maintenance or maximum fault conditions. The front shall be
provided with covers/doors of box formation. The rear shall be provided with hinged removable doors
of box formation. The rear doors shall be of double-leaf type with rebated edges and each leaf should
preferably not be wider than 450 mm. Each leaf of door shall have 2 pairs of approved hinges. The
door shall be fitted with approved type of surface- mounted espagnolette or cremate bolts complete
with approved locking device operated by a satin chrome lever handle at the centre fixing. The top
and sides shall be of removable panels. All panels, covers and doors shall be fabricated from electrogalvanised metal plates of thickness not less than 2.3 mm with paint thickness of 90 µm. The interior
and exterior of each cubicle shall be finished with light gray paint (ICI Ref. No: ICI 104 or
OXYPLAST paint: FF160/8250/CS9 and so constructed as to provide a clear, flush and pleasing
appearance. The panels, covers and front doors shall be secured to the enclosure by means of chrome
type of screws with cylindrical knurled head complete with retaining clips. Welded cross struts shall
not be used. Refer to Appendix A – Metal Treatment and Painting Procedure (Electro-Galvanised
Metal Sheet).
The generator switchboard shall be dust and vermin proof. All covers and doors shall be provided
with grommets and seals to exclude dust and dirt. Louvres shall be provided at the sides and back for
adequate ventilation. The whole cubicle shall undergo de-rusting treatment, followed by anti-rust
treatment and with the exterior be finished semi-gloss enamel grey and interior finished matt white.
Busbars shall be tinned hard drawn high conductivity copper of adequate rectangular cross section to
carry continuously the rated normal current at a rated frequency of 50 Hz with a temperature rise in
accordance with the requirements of BS EN 13601. The busbar rating shall be based on the current
density of not more than 1.5 A/sq. mm. Busbars shall be arranged and rigidly mounted on nonhygroscopic insulators so as to withstand any mechanical forces to which they may be subjected
under the maximum fault conditions. Where multiple parallel bars are used, they shall be separated by
tinned copper spacers at spacing equal to the bar thickness. The main busbars shall be run for the full
length of the generator switchboard without reduction in size and shall be arranged in the horizontal
plane and in the order Red phase, Yellow phase, Blue phase and Neutral from back to front. In each
panel, connections shall be Red phase, Yellow phase, Blue phase and Neutral from left to right,
viewed from the front of the panel. The neutral busbar shall be of full size and full length as that of
the phases. Tinned copper earthing bar of 6 mm x 25 mm cross section shall run to the full length at
the base of the generator switchboard. Busbars shall be identified with standard colour code Red,
Yellow, Blue, Black and Green at appropriate points to distinguish the phases, neutral and earth
respectively. Connections from busbars to the switchgears shall be effected by means of copper bars
or copper insulated conductors and shall be identified by means of coloured plastic sleeving or
painting in accordance with the standard colour code. All connections shall be made up with bronze
or other copper alloy bolts and nuts utilizing tension washers on both outer faces. Precautions shall be
taken to prevent overheating through hysteresis and Eddy current losses.
All secondary wiring shall be of not less than 1.5 sq. mm. section insulated with PVC and shall be
fixed securely without strain by cleats of the compression type. All secondary wiring shall be
properly labelled with number sleeves.
Flexible protective conductor of not less than 2.5 sq. mm section insulated with PVC shall be fixed
securely between the lids, doors, cover plates and etc. with electrical equipment attached to them and
the main cubicle to ensure continuity of the protective circuits.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 2 - 7
Section 2 - Standby Generator Specification
All switchgear, controlgear, indicating and measuring instruments, measuring transformers, protective
relays and etc. provided shall comply with the relevant specifications. Automatic changeover
contactors shall be as specified hereinafter.
Refer to 13.2 – Electronic Protection Relay (Section B – Low Voltage Switchboard and Components
Specification).
One number anti-condensation heater shall be installed for every two (2) panels at the generator
switchboards. Each heater shall be complete with automatic thermostat, control switch and indicating
lamp. A tool compartment of sufficient size shall be provided at the base of the generator switchboard
for storage of tool kit used for the generator set. The door for tools compartment shall be hinged type
complete with lockable handle with keys. Engraved labels with white lettering on a black background
made of laminated materials shall be provided and fastened on the front panels of each switchgear
and items of equipment. Wording shall be clear and coincide. Rubber mat of width 1,000 mm and
thickness 12 mm shall be provided in front of the generator switchboard. It shall extend to the full
length of the generator switchboard.
17.0 CHANGEOVER CONTACTOR
The automatic changeover contactor, unless otherwise specified, shall be bar mounted type with fixed
bar and moving shaft made of steel and bearing supports made of aluminium/bronze alloy. They shall
be mechanically held, mechanically and electrically interlocked, double air-break, quick-make and
quick-break type complying fully with IEC 60947. They shall be dust-proof, rust protected, fully
tropicalised and suitable for use on 230/415 V, 50 Hz AC system.
The operating coil shall be 230 V/415 V, 50 Hz AC type and shall operate satisfactorily when the
voltage at the coil terminals is between 85% and 110% of the nominal voltage. The electromagnet
shall be of laminated type. The automatic changeover contactors shall be four pole types. Each pole
shall comprise three main parts: •
•
•
•
•
•
The main contacts shall be of 'butt-contact' pattern without sliding or rolling and shall operate
with absolute minimum contact bounce.
The blow out coil shall be rated to carry the total current flowing through the main pole and
according to the thermal rating of the contactor.
The arc chute shall be De-ion type or the type having 'arc splitter' for rapid extinction of electric
arc. Each arc chute shall have a steatite disc on its internal faces for preventing rapid erosion of
the chute by the effect of arcs. The arc chutes shall be easily removable to allow inspection of
the main contacts and where necessary their replacement.
The main contacts shall be able to carry continuously the rated current without damage in an
enclosure having an ambient temperature up to 40 degrees Celsius. They shall be of category
AC 4 as defined in IEC 60947.
Unless otherwise specified, a minimum of four normally close and four normally open auxiliary
contacts shall provided.
A transparent protection screen of full compartment size shall be provided in front of the
automatic changeover contactor.
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Issue 01 / Revision 01
February 2007
Sec 2 - 8
Section 2 - Standby Generator Specification
18.0 EARTHING SYSTEM
Independent earthing system shall be provided for each generator set. Earthing to earth Resistance not
exceeding one (1) Ohm (Ω) shall be effected by 3 mm x 25 mm copper tape and 16 mm diameter
copper jacketed steel core rods. The copper jacket shall be of minimum thickness 0.25 mm and shall
be permanently bonded to the steel core to ensure that the copper jacket and steel core are not
separable. Earth chambers and covers used for earthing rods shall be reinforced concrete type. Each
generator set earthing point shall be identified by permanent label legibly marked with the words
'GEN-SET EARTH' permanently fixed to the point of connection of every earthing conductor and the
earth electrode.
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February 2007
Sec 2 - 9
Section 3 - Small Power and Lighting
Section 3
Small Power and Lighting
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 3 – Small Power and Lighting
Page
Section 3 – Small Power and Lighting
1.0
Material Panel
3-1
2.0
Distribution Board
3-1
3.0
PVC Electrical Conduit and Fittings
3-2
4.0
Spacer Bar Saddles
3-2
5.0
Distance Saddle
3-2
6.0
Ceiling Fan
3-2
7.0
Light Fittings and Ancillary Equipment to Lamps
3-3
7.1
Light Fittings for Use with Tubular Fluorescent Lamps
3-3
7.2
Flexible Cords
3-3
7.3
Installation of Fluorescent Light Fittings
3-3
7.4
Self-Contained Emergency Lights
3-3
7.5
Light Fittings to be Supplied and Installed
3-4
7.6
LUX Levels
3-4
8.0
9.0
Street and Perimeter Lighting
3-4
8.1
Scope of Works
3-4
8.2
Light Distribution
3-4
8.3
Street Lighting Lanterns
3-5
8.4
High Pressure Sodium Vapour (HPSV) Lamp
3-5
8.5
Columns and Bracket Arms
3-6
Materials and Equipment
3-7
9.1
General
3-7
9.2
Ballast
3-7
9.3
Ignitors
3-7
9.4
Service Fuse / Cut-Outs.
3-7
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
i
Section 3 - Small Power and Lighting
SECTION 3 – SMALL POWER AND LIGHTING
1.0 MATERIAL PANEL
Provision shall be made in the panels for the installation of the meters by TNB. Sufficient length of
cable shall be provided for termination of cables at the meters.
2.0 DISTRIBUTION BOARD
The boards shall be provided with Miniature Circuit Breakers (MCB) and arranged in such a manner
that the incoming cables to the MCB is connected direct to the other MCB terminal. It shall be so
designed that the MCB can be replaced without disturbing or removing the adjacent units and busbar
connectors. All boards shall incorporate a main isolator of appropriate rating, which shall be positioned
at the lower part of the panel along the centerline. The interior of the panel shall be provided with a
removable internal shroud, giving access to the MCB dollies, but covering the reminder of the interior
for neat appearance after wiring. The internal shroud shall be off the same finish as the exterior of the
board. Labels for phase and circuit identification and current ratings shall be fixed on this internal
shroud either above or below the dollies.
On the outside face of each board cover, a black Perspex label with the number of the distribution board
and engraved in the white on chrome-yellow lettering shall be provided and fixed thereon. For TPN
type distribution boards, bearing the letters: “DANGER 415V; 3-PHASE SUPPLY” engraved in red
color thereon shall be installed.
Isolators used shall be of the heavy duty “ON LOAD” type and of a approved make.
All distribution boards shall be fitted with suitable means for terminating incoming and outgoing cables
and final subcircuit wiring.
The distribution board shall be of totally enclose type construction and be suitable for installation on
walls or be recessed in walls of buildings. All boards shall be rated for the intended voltage and be in
accordance with relevant British Standard.
Busbars for the main shall be of copper and sized in accordance with the relevant British Standard.
Unless otherwise noted full size neutral busbars shall be provided. Busbars shall be braced throughout
to conform to standard practice governing short circuit stresses in distribution boards.
Spare ways shall be installed with MCBs and be fully wired and labeled.
For those not exposed to the sewage emitted vapors and gases, the distribution board panel thickness
shall be of 2 mm and 60 µm of paint thickness. However for distribution boards in contact with the
sewage emitted vapors and gases shall be of 2.3 mm in thickness and 90 µm of paint thickness.
Electrical Works Specifications
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February 2007
Sec 3 - 1
Section 3 - Small Power and Lighting
3.0 PVC ELECTRICAL CONDUIT AND FITTINGS
The PVC Electrical Conduit and Fittings shall be of proven durable and effective for years maintenance
free performance in exposed and encased applications in accordance with NEMA TC-2 Specification.
All conduit and its fitting materials shall comply to the following:
• Rigid Non-metallic Conduit: Schedule 40, high impact PVC with 5,000 psi tensile strength at
73.4 degrees F and approved for 90 degrees C rated by UL Standard 651.
• Corrosion Proof : Resistant to most chemicals
• Properties make shall be of PVC fire resistant.
• Non-Magnetic and Non-Galvanic: Properties shall be of good insulation and No power loss or
conductor heating.
4.0 SPACER BAR SADDLES
Spacer bar saddles and bases shall be of Rigid Non-metallic, Schedule 40 high impact PVC with 5,000
psi tensile strength at 73.4 degrees F and approved for 90 degrees C rated by UL standard 651. Saddle
bases shall be 3 mm deep and may be solid or pressed from PVC of not less than 1 mm thick.
Saddle tops shall be fluted. The screw holes shall be of either slotted or keyhole pattern to permit the
assembly and removal of the saddle top without removal of the retaining screws.
Retaining screws shall be 2 BA in size and be of brass or steel and zinc plated to comply with BS 3382:
Part 2. Retaining screws shall engage not less than 1.5 full thread in bases pressed from steel.
5.0 DISTANCE SADDLE
Distance saddle shall be of Rigid Non-metallic, Schedule 40 high impact PVC with 5,000 psi tensile
strength at 73.4 degrees F and approved for 90 degrees C rated by UL Standard 651. Saddle bases solid
or pressed from PVC of not less than 1 mm thick.
Saddle bases shall be of such depth that the nominal clearance of 6 mm between the conduit and the
wall of surface to which the saddle are fixed is provided.
Retaining screws for saddle tops shall be of brass complying with BS 3382.
6.0 CEILING FAN
Ceiling fans shall be 1,524 mm sweep model fitted with capacitor type motor suitable for operation on
240V 50Hz AC single-phase and supplied complete with down rods to suit mounting heights and speed
regulators.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 3 - 2
Section 3 - Small Power and Lighting
7.0 LIGHT FITTINGS AND ANCILLARY EQUIPMENT TO
LAMPS
7.1
Light Fittings for Use with Tubular Fluorescent Lamps
All fluorescent tubes shall comply with MS 619 or relevant British Standard and be of 26 mm diameter.
They shall be “switch-start”, “white light” with a correlated color temperature of 3,000°K and have
average life span of 15,000 hours. The lamp lumens shall be 3,200.
Lamp holders shall be bi-pin, spring loaded, designed to retain positively the lamp caps independently
of the contact springs and of robust construction complying with BS 5101.
Power factor correction capacitors shall be of the metal foil type enclosed in a metal case with two
insulated connections, safety discharge resistor and impregnated with “Arcolor” or other approved
medium. Power factor shall be corrected to capacitors shall comply with the relevant British Standard
or MS 279.
Ballast for fluorescent lamps shall be polyester vacuum impregnated, built-in, switch-start type, having
a hot loss of 8 W (for 36 W lamp) and comply with BS 2818.
Diffusers depend on type of fittings.
7.2
Flexible Cords
Flexible cards for use with light fittings employing tubular fluorescent lamps, or apparatus operating at
normal room temperature shall comply with BS 6500 and shall have conductor of plain copper.
7.3
Installation of Fluorescent Light Fittings
All fluorescent light fittings shall be supplied complete with tubes, lampholders and control gear. They
shall be completely wired and fully tested to ensure reliable performance and quality. All internal
wiring shall be neatly arranged and taped with intermediate terminals provided with external
connection. All wiring shall be of heat resistant type and be PVC insulated.
Brass earthing screws with spider washers shall be provided for earthing the fittings.
The cutting of down rods or the provision of extended down rods to suite mounting height shall be
undertaken. Where fluorescent light fittings are to be installed on the underside of the ceilings, suitable
spacers which shall be inserted between the top of the fittings and underside of the ceiling in such a
manner as to allow a minimum clearance of 12 mm shall be provided.
7.4
Self-Contained Emergency Lights
The unit shall be designed such that the cover can be readily removed for ease of installation. The unit
shall be suitable for mounting on walls or on ceiling as required. The diffuser shall be of clear acrylic.
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February 2007
Sec 3 - 3
Section 3 - Small Power and Lighting
The unit shall be equipped with nickel cadmium sealed cells and an automatic charger main failure
relay and shall be maintenance free. The emergency duration shall not be less than 3 hours for a fully
charged battery.
Illumination shall be provided by one 300 mm 10 W fluorescent lamp. The unit shall be equipped with
LED to indicate mains ‘on’ and a test switch to simulate main failure.
7.5
•
•
•
•
•
7.6
Light Fittings to be Supplied and Installed
2 x 36 W fluorescent fitting c/w acrylic prismatic diffuser corrosion resistent recessed mounted.
2 x 36 W fluorescent fitting c/w acrylic prismatic diffuser corrosion resistent surface mounted.
150 W sodium vapour explosion proof floodlight lamps.
150 W sodium vapour weatherproof floodlight lamps.
1 x 70 W high-pressure sodium street lighting fitting c/w single arm and 3 m pole and
accessories.
LUX Levels
The lighting for the various location listed below shall be as follows: (a)
(b)
(c)
Pump room, blower room, switchboard room, workshop, equipment rooms and other enclosed
work areas – 500 Lux
Office, Administration Area – 350 Lux
Toilets, pantry, corridors, walkways, staircase and etc. – 250 Lux
8.0 STREET AND PERIMETER LIGHTING
8.1
Scope of Works
The works shall be consist of the supply and delivery to site of lanterns, fittings, switch-gears, bracket
arm, columns, bases, cable, feeder pillars and all necessary ancillary equipment for the assembly,
erection, connection, testing and commissioning of the complete street lighting system.
The work shall also include the supply and delivery of one hydraulic working platform.
8.2
Light Distribution
The light distribution for all the street lanterns shall be of cut-off. It could be either semi-cut-off or fully
cut-off.
The specification of the lighting scheme shall conform to the following: The road shall be assumed with an average road luminance factor of 0.08, a specular factor of 0.37 and
maintenance factor of 0.7.
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February 2007
Sec 3 - 4
Section 3 - Small Power and Lighting
The light distribution shall consist of: (a)
(b)
(c)
8.3
Minimum average road surface luminance of 30 Lux
Minimum average perimeter luminance of 150 Lux
Uniformity of luminance i.e. L min/L av. of 0.4.
Street Lighting Lanterns
All lanterns shall be new, totally enclosed, dustproof, insect proof and watertight and shall be tested in
accordance with BS 4533 part 2. All exposed parts shall be of non-corrosive stainless steel materials.
The lanterns shall provide the required light distribution with the size and type of lamp specified. The
light distribution shall be semi cut-off or cut-off. Each lantern shall be supplied complete with all the
necessary integral control gear fully wired and ready for erection.
The lantern wiring shall be of the size and insulated with materials that will more than effectively
withstand the current, voltage and temperatures expected within the lantern during both the starting and
operating model in the ambient temperature of the site.
The lamp compartment of the lantern shall be accessible via a hinged, glazed acrylic bowl which shall,
in the closed position, bed firmly upon a soft resilient neoprene gasket shall be positively secured in the
lantern housing and shall be of weather resistant type. The bowl and its frame or housing shall be
secured firmly to the lantern body, by means of stainless steel clips and hinge pins. In the lowered
position of the bowl it shall be restrained from becoming detached or being blown against the other
portion of the lantern or the column arm.
The polar curves of the lanterns in both horizontal and vertical planes shall be smooth and free from any
abrupt variations so that the luminous intensity diminished smoothly and progressively from the
maximum. The lantern shall incorporate high intensity aluminium mirrors, chemically anodized to yield
optimum reflection of light distribution.
8.4
High Pressure Sodium Vapour (HPSV) Lamp
All lamp supplied shall be of a High Pressure Sodium Vapour (HPSV) type and shall have a colour
temperature of approximately 2100°K and 5000°K respectively. The majority of the light output shall
fall within the 560-610 nanometre waveband i.e. Yellow/Orange range for the HPSV.
The lamp shall have an initial luminous efficiency of approximately 83 lumens per watt.
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February 2007
Sec 3 - 5
Section 3 - Small Power and Lighting
8.5
Columns and Bracket Arms
All Columns and bracket arms shall be manufactured to comply with BS 1840: 1972. The columns and
bracket arms shall be manufactured from steel conforming to BS 4360: 1976 – Grade 43C or Grade
50C. The columns shall be of continuously tapered octagonal sections, connected together by forced fit
slip joints. Each column shall have a base compartment and a weatherproof door, measuring 600 mm x
130 mm, with a tamperproof column and be flush with the column, providing a watertight fitting
against a non-perishable resilient gasket. Door keys shall be supplied at the completion.
The columns shall be supported connected by flange plates on concrete footings. Flange plates shall be
of at least 18 mm thickness. Concrete footings shall be cast with appropriately sized holding down bolts
as recommended by the column manufacturer and have lead-in / lead-out ducts and shall be responsible
for the size of the concrete footings depending on soil conditions.
A 16 mm thick Tufnol baseboard, measuring 600 mm x 130 mm, shall be included in the base
compartment. The baseboard shall be securely fixed in position inside the column by countersunk screw
to hidden treaded bushes. No part of this fixing shall protrude through the column.
All metal parts of each column shall be earthed and the column and bracket arms shall be electrically
continuous.
A corrosion resistant electrical earthing terminal in the form of a stud of not less than 6 mm in the
diameter and 20 mm long shall be attached close to the door opening within each column. Two suitable
sized washers and two nuts shall be fitted.
All columns shall be erected in to a perpendicular position with the door on the opposite side to the oncoming traffic except at the parapets of bridges and retaining walls. In each run of columns of five or
more, every fifth column shall be checked for vertically with a theodolite. If less than five columns are
erected in line than one column shall be so checked. Shim washers may be use to achieve vertically
where necessary.
The bracket arms shall be of the safe shape and finish as the column. The smaller end of the curve arm
finish with a spigot, suitable for the safe mounting of the lantern to be installed.
Individual sections of each column, bracket arm and flange plate shall be protected against corrosion by
hot-dip galvanising internally and externally in accordance with BS 729: 1971.
All welding work shall be done prior to galvanising. The joining of two parts by welding after
galvanising shall not be permitted. The treatment prior to galvanising shall include degreasing, rinsing,
pickling, then rinsing and fluxing. Post treatment such as chromating or phosphating shall then be
applied. The minimum average zinc coating weight shall conform to the recommendations of BS 729.
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February 2007
Sec 3 - 6
Section 3 - Small Power and Lighting
9.0 MATERIALS AND EQUIPMENT
9.1
General
Items of equipment and material shall have maker’s specification agreeing with those of British
Standard. The equipment offered shall be suitable for continuous trouble free operation under adverse
conditions.
9.2
Ballast
Only ballast manufactured for high-pressure sodium vapour lamp applicants shall be used. The
combination of MBF control gear and retrofit sodium vapour lamp shall not be acceptable.
The ballast shall be an open style polyester resin filled type. It shall be enclosed in the suitable steel
canister, encapsulated and finished in white enamel. The windings shall be dual polyester amide / amide
copper wire, and both windings and core insulation materials shall be Class H. The ballast shall be
designed to operate over a range of main voltage from 200 to 250 volts by means of suitable tapings.
9.3
Ignitors
Ignitors for the HPSV lamps shall be rated with the appropriate voltage. The unit shall be capable of
operating from a range of voltage from 200 to 250 volts. The ignitor shall be highly efficient, housed in
a cylindrical aluminium canister and provided with ‘wither pin’ terminations of ‘flying leads’.
The ignitor shall be of the Pulse Transformer type incorporating electronic circuitry and suitable for the
type of ballast’s and lamp to be installed. The output pulse shall be substantially independent of both
supply voltage and ballast parameter. A cut-out circuit shall be incorporated so that pulsing will cease
after approximately two minutes, in the event of no ignition.
9.4
Service Fuse / Cut-Outs.
The service fuse / cut-outs shall be of an approved equivalent.
Service fuse unit for each lantern shall be of the correct rating and of HRC type. The unit housing has
high mechanical and dielectric strength, and shall be suitable for use in the tropics.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 3 - 7
Section 4 - High Tension Components Specifications
Section 4
High Tension Components
Specifications
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 4 – High Tension Components Specifications
Page
Section 4 - High Tension Components Specifications
1.0
11 kV / 22 kV Vacuum Circuit Breaker Specification
4-1
1.1
General
4-1
1.2
Design Features and Construction
4-1
1.2.1 Cubicles
4-1
Main Components
4-2
1.3.1 Incoming circuit breaker
4-2
1.3.2 Outgoing feeder circuit breaker
4-2
1.3.3 Bush bar Chamber
4-2
Description
4-2
1.4.1 Circuit breaker compartment
4-2
1.4.2 Metering compartment
4-3
1.4.3 Bus bar compartment
4-3
1.4.4 Potential Transformer
4-3
1.4.5 Metal Treatment
4-4
1.4.6 Tests
4-4
1.5
Required Technical Parameters
4-4
1.6
Specification for Panels
4-4
1.6.1 Incomer Panels
4-4
1.6.2 Outgoing Panels
4-5
1.3
1.4
2.0
Specification for 11 kV Oil Immersed Natural Cooled Transformers
4-6
2.1
General
4-6
2.2
Standards and Approval
4-6
2.3
Transformers
4-6
2.4
Type of Transformer
4-6
2.5
Voltage Ratios
4-6
2.6
Winding Connections and Vector Group
4-7
2.7
Impulse Withstand Voltage
4-7
2.8
Impedance Voltage
4-7
2.9
Flux Density
4-7
2.10
Tapping Range and Method
4-7
2.11
Limits of Temperature Rise
4-8
2.12
Class of Winding Insulation
4-8
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
i
Section 4 – High Tension Components Specifications
3.0
4.0
2.13
Cooling System
4-8
2.14
Fittings
4-8
2.15
Terminal Marking and Rating Plates
4-9
2.16
Oil
4-9
2.17
Earthing
4-9
2.18
Transformer Room
4-10
Cast Resin Transformer
4-11
3.1
Scope
4-11
3.2
Standards
4-11
3.3
Description
4-11
3.3.1 Magnetic Core
4-11
3.3.2 LV Windings
4-12
3.3.3 HV Windings
4-12
3.3.4 MV Winding Support Spacers
4-12
3.3.5 HV Connections
4-13
3.3.6 LV Connections
4-13
3.3.7 HV Tapping
4-13
3.4
Accessories and Standard Equipment
4-14
3.5
Thermal Protection
4-14
3.6
Metal Enclosure
4-14
3.7
Electrical Protection
4-15
3.7.1 Protection relay
4-15
3.7.2 MV surge arresters
4-15
3.7.3 RC filters (repetitive switching operations)
4-15
3.8
Climatic and Environmental Classifications
4-16
3.9
Fire Behaviour Classification
4-16
11 kV CABLE SPECIFICATION
4-17
4.1
Types Of Cables
4-17
4.2
Cable Trench
4-17
4.3
Cable Ducts
4-17
4.4
Cable Marker
4-18
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
ii
Section 4 - High Tension Components Specification
SECTION 4 - HIGH TENSION COMPONENTS
SPECIFICATIONS
1.0 11 kV / 22kV Vacuum Circuit Breaker Specification
1.1
General
This specification covers the technical details of operating requirement, constructional details and
provides some guidelines for testing of 11 kV Vacuum circuit breaker and panel. The panel shall be
made out of 2 mm. CRCA steel sheet, dust & vermin proof, duly painted with red oxide & powder
coated with steel grey paint after pretreatment of acid/alkali wash with a provision for incoming side
cable entry & outgoing bottom cable entry. This specification shall be applicable for indoor installed
switchboard connected to control incoming supply and to primary side of power transformers.
All circuit breakers shall be arranged for Solenoid closes and shunt tripping, both operating from 110
V.D.C. source. The close/trip control switch shall be of pistol grip type. The closing and tripping
circuits shall be self-opening on completion of their respective functions irrespective of the position
of the control switch. A readily identifiable mechanical trip device shall be provided with each
breaker.
The mechanism shall be trip-free at any position of the closing stroke. A visual ON/OFF indicator
shall be provided positively coupled to the operating mechanism. Manual charging facility of the
spring and manual tripping arrangement shall also be provided. Anti-pumping facility shall be
provided.
1.2
Design Features and Construction
1.2.1 Cubicles
Each unit shall be housed in a 2 mm thick MS steel sheet cubicle having the bus-bars, C.T.'s, main
and control cable c/w terminals, nations, all at the rear and accessible by removing detachable panels.
A lockable hinged lift off type front door shall enclose the truck and shall carry the control switches,
indicating instruments and lamps. Fuses shall be mounted on the fixed part of the cubicle, preferably
at the rear. The ammeter shall have red mark at full load rating.
Protection relays shall be mounted on a separate swing panel above the cubicle frame work. The
panel should conf. to IP54 degree of protection.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 1
Section 4 - High Tension Components Specification
1.3
Main Components
1.3.1 Incoming circuit breaker
This shall be provided with protective and instrument panel. This shall be drawn out type with
vertical isolation and bus bar chamber for inter-trunking with other breakers. Incoming cable box
shall be provided with provision for spare cable entry.
1.3.2 Outgoing feeder circuit breaker
This shall be provided with protective and instrumental panel. This shall be draw out type with
vertical isolation and bus bar chamber for inter trucking with other breakers. Outgoing cable box
shall be provided.
1.3.3 Bus bar Chamber
•
•
•
•
•
•
•
•
•
•
•
•
Adequately rated potential transformer/current transformer
Complete with protection fuses
Indicating and measuring devices
Protective relays
Trip free operating mechanism
Safety interlocks
Wiring for control circuit, measuring, indicating and protective devices
Frame earthing
Operation counters
"ON" and "TRIP" push button
Pressure release vent
Test terminal blocks
1.4
Description
1.4.1 Circuit breaker compartment
This compartment shall consist of a truck carriage on rollers on which the circuit breaker shall be
mounted. The raising and lowering mechanism shall be designed so as to enable the breaker to be
plugged in or out with minimum physical strain. The mechanism employed shall enable the breakers
to be self-supporting at all positions. Positive interlocks shall be provided to ensure that the circuit
breaker is taken out from or put into service position only when it is in “OFF" position. Further more,
circuit breaker shall be operable only when it is in "FULL SERVICE" position or in "TEST" position.
The circuit breaker shall be provided with a manually charged spring assisted stored energy closing
mechanism with electrical tripping and switching device. The following mechanical and electrical
interlocks shall be provided in the spring charging mechanism.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 2
Section 4 - High Tension Components Specification
When the breaker is in "ON" position it will not be possible to charge the main spring. It will not be
possible to close the circuit breaker if the spring is not fully charged. Rapid opening of the breaker
will be ensured.
1.4.2 Metering compartment
Each unit should have its own metering chamber with hinged door, centralized wiring and fuses. The
meters provided should be flush type and mounted on floor.
1.4.3 Bus bar compartment
All bus bars shall be air-insulated, PVC encapsulated, amply rated and shall be fitted in the top rear
position. The bus bars and their main current carrying connections shall have the same sectional area
through out their length.
Where bus bars are taken through the partitions of adjacent cubicle, sealing shall be provided to
prevent spread of fire from one unit to the next.
The bus bar shall be of hard drawn copper and these shall be supported on suitable insulating
materials at sufficiently close intervals to prevent bus bar sag and to effectively withstand electromagnetic stresses in the event of short circuit.
Provision for the interconnection of the circuit breakers by trucking arrangement and through terminal
box shall be provided. Each group of bus bar feeder spouts shall be fitted with automatically operated
safety shutters.
All incomer panels, sectionaliser and other feeders shall be provided with: •
One set of 3 single phase bar primary current transformer for instrumentation of panel
(Accuracy Class 0.5)
•
One set of 3 single phase bar primary current transformer for protective devices (Accuracy
Class 5 P 10)
The switchgear shall be provided with cable sealing hoses to in terminate the incoming and outgoing
cables.
1.4.4 Potential Transformer
All incomer panels and sectionliser shall be provided with adequately rated 3 phase, 11 kV/110 Volts,
200 VA potential transformers with current limiting resistors and H.T. & L.T. fuses for protection.
These shall be used for all measuring instruments proposed in the Technical Parameters and to
provide control circuit actuation of all the panels of the switchboard.
The potential transformers shall be core type air insulated and housed in sheet steel cubicles. Indoor
plugs shall be provided for simulation disconnections of both primary and secondary winding of the
transformer. Causing of the potential transformers shall be efficiently earthed.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 3
Section 4 - High Tension Components Specification
1.4.5 Metal Treatment
Enclosure shall undergo rigorous rust proofing process comprising of alkaline degreasing, pickling,
phosphate coating of primer and finally standard approved colour to provide an elegant and enduring
finish.
1.4.6 Tests
Shall ensure that the tests mentioned in BS 2037, BS 116 or relevant have been performed.
1.5
Required Technical Parameters
Service
Nominal System Voltage
Highest System Voltage
No. Of phases
Frequency
System Earthing
Type
Symmetrical breaking capacity
Short Time breaking capacity
Rated insulation Levels
Withstand voltage
Impulse withstand test voltage
(1.2/50 microsecond wave)
Class of Insulation
Bus bar capacity
Bus bar material
Maximum ambient temperature
1.6
: Indoor
: 11 kV / 22 kV
: 12 kV / 24 kV
: 3 (three)
: 50 HZ
: Non effectively Earthed system
: Vacuum Circuit Breaker
: 26.2 kA corresponding to 500 MVA
: 26.2 kA
: One minute power frequency
: 28 kV RMS
: With standard full wave
: 75 kV Peak
:B
: 800 AMPS
: Electrolytic copper
: 50 degree C
Specification for Panels
1.6.1 Incomer Panels
No. Of units required
Nominal rated current
Purpose
C.T Ratio
Incoming Cable Size
Potential Transformer
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
: One No.
: 630 AMPS
: To control the incoming power supply
: 100-50/5+5 having 15 VA burden per core &
accuracy Cl.:0.5 for meter & 5 P 10 for protections
: 1 No.11 kV x 3 x 120 sq.mm XLPE Copper conductor
cable
: 1 No. 11 kV/110 V, 200 VA per phase & Cl.: 1
accuracy for metering & protective Relays
Sec 4 - 4
Section 4 - High Tension Components Specification
Protections
Measuring Instruments
Indicating Lamps
: - Numerical Type, Microprocessor based, one 3 Ph.
- IDMT and high set instantaneous relay consisting
of three overload units (Range 50% to 200%) one
earth fault unit (range 5% to 80%) & three high set
instantaneous units
- 1 Single pole instantaneous relay for heavy earth fault
with setting 5-80%
- Over voltage Relay
: - Ammeter with selector switch (Duel Range)
- Voltmeter with selector switch (Range 0 - 15 kV)
: - GREEN for breaker 'OFF'
- RED for breaker 'ON'
- AMBER for breaker 'AUTO TRIP' on fault
- WHITE for ‘TRIP CIRCUIT HEALTHY’
1.6.2 Outgoing Panels
No. Of units required
: 3 Nos. (Three)
Nominal rated current
Label Reading
Purpose
C.T. Ratio
: 630 Amps
: Transformer Feeder.
: Control of supply to transformer
: 30/5+5 Amps having 15 VA burden per core &
accuracy Cl.:0.5 for meter & 5 P 10 for protections
: 1 No. 11 kV x 3 C x 120 sq.mm XLPE Copper
Conductor Cable for each panel.
Outgoing cable size
Measuring Instruments
Protections
Indicating Lamps
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
: Ammeter with selector switch (Range 0-30 A)
: - Numerical Type, Microprocessor based, combined
IDMT and high set instantaneous relay consisting of three
overload units (Range 50% to 200%) one earth fault unit
(range 5% to 80%) & three high set instantaneous units.
- Over Voltage Relay
: - GREEN for breaker 'OFF'
- RED for breaker 'ON'
- AMBER for breaker 'AUTO TRIP’ on fault.
- WHITE for ‘TRIP CIRCUIT HEALTHY
Sec 4 - 5
Section 4 - High Tension Components Specification
2.0 Specification for 11 kV Oil Immersed Natural Cooled
Transformers
2.1
General
This section of the Specification describes and specifies requirements for 11 kV / 415 V distribution
transformer.
2.2
Standards and Approval
The transformers shall comply with the latest relevant British Standard Specifications, Malaysia
Standard or IEC.
2.3
Transformers
The transformers shall be suitable for continuous operation on 3 phase, 50 Hz electrical power
distribution system with neutral earthing conditions and maximum phase fault levels as follows :•
•
•
•
•
11 kV
350 MVA6.6kV
150 MVA3.3 kV
75 MVA415V
31 MVA
They shall be fully tropicalised and suitable for continuous operation at an ambient temperature up to
40 degree Celsius, relative humidity up to 100%, isoceraunic level up to 200 days per-annum and
altitude up to 1,000 meters above sea level.
2.4
Type of Transformer
The transformers shall be oil-immersed natural cooled and hermetically sealed type complying with
BS 171 or IEC 76 and suitable for indoor duties. Unless otherwise specified, they shall be low loss,
step-down type of distribution transformers fitted with skid type bases.
2.5
Voltage Ratios
The standard voltage ratios at no-load shall be as:
(a)
(b)
(c)
11000/433-250 V, so as to deliver load at the declared voltage of 415/240 Volts, 3 phase, 4 wire
system with the neutral solidly earthed.
11000/3300 V
6600/433-250 V
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 6
Section 4 - High Tension Components Specification
2.6
Winding Connections and Vector Group
Unless otherwise specified, the winding of all 3 phase step-down transformers shall be connected as
follows:Higher Voltage – Delta Lower Voltage - Star Vector Group - Dyn11
2.7
Impulse Withstand Voltage
Completed transformers arranged for service but with arcing horns removed shall be capable of
withstanding the following negative polarity 1.2/50 microseconds impulse voltage on the higher
voltage windings:Nominal System Voltage Impulse Withstand Voltage (Volt rms) (kV peak)
3300
6600
11000
45
60
75
All impulse shall be carried out in accordance with the provisions of BS 923 BS 171 or IEC 76.Type
test certificates may be accepted in lieu of separate impulse tests at the discretion of the IWK/JPP
2.8
Impedance Voltage
For the purpose of protection against short circuit stresses, the minimum value of impedance voltage
at 75 degrees Celsius rated current shall be as follows: -4.75% for transformer up to 1,000 kVA.
5.5% for transformer between 1,000 – 1,500 kVA 6.0% for transformer between 1,500 - 2,000 kVA.
2.9
Flux Density
The maximum flux density at any point in the magnetic
circuit when the transformer is connected
on the principal tapping and operating at normal voltage and frequency shall normally be in the
region of 1.55 to 1.65 Tesla, but at the time of tendering alternative designs employing higher flux
densities may be may be submitted. However with such higher flux densities for consideration the
magnetic circuit shall not unduly saturate during system over voltage conditions.
2.10 Tapping Range and Method
Tapping shall be provided on the higher voltage winding for a variation of the no-load voltage of +
5.0%, + 2.5%, 0%, - 2.5% and-5.0%. All tap changing shall be carried out with the transformers off
circuit by means of an externally operated tapping switch with tap position indications. The operation
handle shall be mounted on the tank side and provision shall be made for padlocking in any tap
position. Padlocks of any approved type shall be supplied.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 7
Section 4 - High Tension Components Specification
2.11 Limits of Temperature Rise
The transformers shall be designed for continuous operation at their rated power without exceeding
the temperature rise limits as follows:•
•
In Top Oil
In Inding
: 50 degrees Celsius
: 55 degrees Celsius
2.12 Class of Winding Insulation
The Class of winding insulation shall be Class A to BS 2757.
2.13 Cooling System
Cooling tubes or fins shall be fitted on the sides of the transformer. The arrangement of the tubes or
fins shall be such that all painted surfaces can be readily cleaned and painted in position. The tubes or
fins shall be designed to allow free circulation of oil and to prevent any accumulation of moisture.
2.14 Fittings
Unless otherwise stated in the in the specification transformers covered by this specification shall be
provided with the following standard fittings: •
•
•
•
•
•
•
•
•
•
•
•
•
Terminal Marking and Rating Plates
Lifting Lugs
Jacking Lugs
Earthing Terminal (two numbers on opposite side)
Oil Level Indicator
Oil Temperature Indicator
Thermometer Pocket
Winding Temperature Indicator
Drain Valve
Filter Valve
Pressure/Vacuum Bleeding Device
Pressure/Vacuum Relief Device
Pressure/Vacuum Gauge
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 8
Section 4 - High Tension Components Specification
2.15 Terminal Marking and Rating Plates
The terminal marking plate shall show a plan view of the terminals with the characters of terminal
markings as per Appendix D of BS 171 or IEC 76 engraved thereon. It shall also show the tappings in
a tabulated form. The rating plate shall indicate the following:•
•
•
•
•
•
−
−
•
−
−
•
•
•
•
Manufacturer's name and address
Transformer Specification Reference
Manufacturer's Serial Number
Year Of Manufacture
Rating in kVA
Volts at no-load on normal tapping :High Voltage
Low Voltage
Current at rated load on normal tapping :High Voltage
Low Voltage
Number of phases
Frequency
Vector Group Symbol
% Impedance Voltage at Normal Tapping at 75 degrees Celsius
The terminal marking and rating plates shall be of a durable and corrosion resisting material and the
markings thereon shall be permanently legible. The two plates may be combined into a single plate.
2.16 Oil
Transformers shall be supplied filled with oil and hermetically sealed. The oil shall meet the
requirements of BS 148 and shall be completely free from PCB.
2.17 Earthing
The neutral point of the low voltage system of the transformer shall be solidly earned to achieve an
earth resistance not exceeding one ohm. The frameworks and all non-current carrying metal parts of
the transformer shall be earthed similarly to achieve an earth resistance not exceeding one ohm. An
earth bar of flat hard drawn copper with dimension not less than 25 mm x 6 mm shall be installed
around the four walls of the transformer room at a height of 300 mm from the finished floor level.
The earth bar shall be bolted to the frame earth of the transformer. All joints of the earth bar shall be
tinned and bolted. The earth bars shall be painted with approved green enamel.
Unless otherwise specified, the neutral earth and the frame earth of the transformer shall be separately
connected to its own group of earth electrodes. The neutral earth and the frame earth shall be
connected to its electrodes by means of two numbers green PVC insulated copper cable of cross
sectional area not less than 70 sq.mm.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 9
Section 4 - High Tension Components Specification
The two groups of earth electrodes after having been hang verifies by the IWK/JPP. Each of earth
resistance not exceeding one ohm, shall be linked together by means of PVC cables as mentioned
above unless otherwise specified. At least two points of the frame earth system of the transformer
shall be connected to the earth electrodes.
Earth electrodes shall be of copper jacketed steel core rods with 16 mm diameter and supplied in 2.4
m length and shall have provision for screw coupling with another standard length. The copper jacket
shall be of minimum thickness 0.25 mm and shall bi-metallically bonded to the steel core to ensure
that the copper jacket and steel core are not separable. Where the desired earth resistance value cannot
be driven, sufficient number of sets of earth electrodes shall be installed outside the resistance area
and linked together by PVC copper cables as mentioned above until the required value is reached.
Each set of earth electrode shall be provided with brass connecting clamp and approved type of precast heavy duty concrete inspection chamber with removable cover.
The earthing points shall be identified by permanent label legibly marked with the words
`Transformer Frame Earth' or `Transformer Neutral Earth' permanently fixed at the point of
connection of every earthing conductor to an earth electrode.
2.18 Transformer Room
Approved type of rubber mat shall be provided around the transformers. The rubber mat shall extend
to the full length and width of the transformer and shall be of thickness not less than 12 mm and
width 1,000 mm.
`BAHAYA' sign, `DILARANG MASUK' sign, sign indicating `Substation No:' and shock treatment
chart shall be installed to the requirement of the Suruhanjaya Tenaga. ` DILARANG MEROKOK '
sign shall also be installed.
All trenches in the transformer rooms shall be filled up with clean sand to a level above cable ducts.
As fitted layout plans, schematic wiring diagrams, and plans showing cable routes and positions of
earthing point with reference to easily recognizable buildings and structures shall be suitably framed
up in the transformer room. These plans and diagrams shall be in addition to the four sets of prints
required to be submitted to the IWK/JPP. All main High voltage switch room, Transformer room
shall be fitted with automatic triggered release CO2 system, controlled by heat and smoke sensor.
.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 10
Section 4 - High Tension Components Specification
3.0 Cast Resin Transformer
3.1
Scope
Three-phase transformers of cast resin type, Class F insulation system with natural (AN) cooling for
indoor installation, destined for use in three-phase HV/LV distribution systems.
If required forced cooling (AF) to increase the rated power up to 40%.
3.2
Standards
These transformers will be in compliance with the following standards:
•
•
•
•
•
•
•
IEC 60076-1 to 60076-5: power transformers
IEC 60076-11 : Dry type transformers
CENELEC Harmonisation Documents
HD 464 S1 : 1988 + / A2 : 1991 + / A3 : 1992 for dry-type power transformers
HD 538-1 S1 : 1992 for three-phase dry-type distribution transformers 50 Hz, from 100
To 2500 kVA with highest voltage for equipment not exceeding 24 kV.
IEC 905: 1987 - Load guide for dry-type power transformers.
These transformers will be manufactured in accordance with:
•
•
3.3
A quality system in conformity with ISO 9001
An environmental management system in conformity with ISO 14001, both certified by an
official independent organisation.
Description
3.3.1 Magnetic Core
This will be made from laminations of grain oriented silicon steel, insulated with mineral oxide and
will be protected against corrosion with a coat of varnish.
In order to reduce the power consumption due to transformer no-load losses, the magnetic core is
stacked using overlapping-interlocking technology, with at least 6 overlaps.
In order to reduce the noise produced by the magnetic core, it is equipped with noise-damping
devices.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 11
Section 4 - High Tension Components Specification
3.3.2 LV Windings
The LV winding is produced using aluminium or copper foils (according to the manufacturer’s
preference) in order to cancel out axial stress during short circuit ; this foil will be insulated between
each layer using a heat-reactivated Class F pre-impregnated epoxy resin film
The ends of the winding are protected and insulated using a Class F insulating material, covered with
heat reactivated epoxy resin
The whole winding assembly will be polymerised throughout by being autoclaved for 2 hours at
130°C, which will ensure:
•
•
•
High level of resistance to industrial environments
Excellent dielectric withstand
Very good resistance to radial stress in the instance of a bolted short circuit.
3.3.3 HV Windings
They will be separated from the LV windings to give an air gap between the MV and LV circuits in
order to avoid depositing of dust on the spacers placed in the radical electrical field and to make
maintenance easier.
These will be independent of the LV windings and will be made of aluminium or copper wire or foil
(according to the manufacturer's preference) with Class F insulation.
The HV windings will be vacuum cast in a Class F fireproof epoxy resin casting system composed of:
•
•
•
An epoxy resin
An anhydride hardener with a flexibilising additive
A flame-retardant filler.
The flame-retardant filler will be thoroughly mixed with the resin and hardener. It will be composed
of trihydrated alumina powder (or aluminium hydroxide) or other flame-retardant products to be
specified, either mixed with silica or not.
The casting system will be of Class F. The interior and exterior of the windings will be reinforced
with a combination of glass fibre to provide thermal shock withstand
3.3.4 MV Winding Support Spacers
These will provide sufficient support in transport, operation and during bolted short circuit conditions
as well as in the case of an earthquake.
These spacers will be circular in shape for easy cleaning. They will give an extended tracking line to
give better dielectric withstand under humid or high dust conditions.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 12
Section 4 - High Tension Components Specification
These spacers will include an elastomer cushion that will allow it to absorb expansion according to
load conditions. This elastomer cushion will be incorporated in the spacer to prevent it being
deteriorated by air or UV.
3.3.5 HV Connections
The HV connections will be made from above on the top of the connection bars. Each bar will be
drilled with a 13 mm hole ready for connection of cable lugs on terminal plates.
The HV connection bars will be in rigid copper bars protected by heat shrinkable tubing.
HV connections in cables are not allowed, in order to avoid all risk of contact, due to cables flapping.
The HV connections will be in copper.
3.3.6 LV Connections
The LV connections will be made from above onto bars located at the top of the coils on the opposite
side to the HV connections.
Connection of the LV neutral will be directly made to the LV terminals between the LV phase bars.
The LV connection bars will be in copper or in tinned aluminium (according to preference of the
manufacturer).
The output from each LV winding will comprise a tin-plated aluminium or copper connection
terminal, enabling all connections to be made without using a contact interface (grease, by-metallic
strip).
These will be assembled according to current practices, notably using spring washers under the
fixings and nuts.
Devices in the 630 to 2,500 kVA range will be easy to connect using factory-built electrical ducting
through an optional interface. Stress withstand in the instance of a bolted short circuit on the
connector will be guaranteed by the manufacturer.
3.3.7 HV Tapping
The tapping which act on the highest voltage adapting the transformer to the real supply voltage
value, will be off-circuit bolted links.
Tapping with connection cables are not allowed.
These bolted links will be attached to the HV coils.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 13
Section 4 - High Tension Components Specification
3.4
Accessories and Standard Equipment
These transformers will be equipped with:
•
•
•
•
•
•
•
•
3.5
4 flat bi-directional rollers
lifting lugs
haulage holes on the underbase
2 earthling terminals
1 rating plate
1 "Danger Electricity" warning label (T 10 warning)
1 routine tests certificate
1 instruction manual for installation, commissioning and maintenance in English.
Thermal Protection
These transformers will be equipped with a thermal protection device which will comprise:
2 sets of 3 PTC sensors, one sensor for "Alarm 1", one for "Alarm 2" per phase, installed in the coils
of the transformer. They will be placed in a tube to enable them to be replaced if ever necessary.
An electronic converter with two independent monitoring circuits equipped with a changeover switch,
one for "Alarm 1" the other for "Alarm 2". The position of the relays will be indicated by different
coloured indicator lights. A third indicator light will indicate the presence of voltage.
These three indicator lights will be on the front of the converter. The electronic converter will be
installed away from the transformer.
A plug-in terminal block for connection of the PTC sensors to the electronic converter.
The PTC sensors will be supplied assembled and wired to the terminal block fixed on the upper part
of the transformer. The converter will be supplied loose with the transformer, packaged complete
with its wiring diagram.
3.6
Metal Enclosure
On request, these transformers will be equipped with a metal enclosure for indoor installation
comprising an integral IP31 (except the base which may be IP21) metal enclosure, that can be
dismantle on request, with:
•
•
•
•
an anti-corrosion protection in the manufacturer's standard colour
lifting lugs enabling the transformer and enclosure assembly to be handled
a bolted access panel on the enclosure front to allow access to the HV connections and to the
tapping. This will be fitted with handles, it will have one "Danger Electricity" warning label (T
10 warning), a rating plate and a visible braid for earthling
blanked off holes for fitting Ronis ELP 1 or alternatively Proflux P1 type key locks on the
bolted access panel to enable it to be locked
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 14
Section 4 - High Tension Components Specification
•
•
•
3.7
2 undrilled gland plates on the roof: one on the HV side, one on the LV side (drilling and cable
gland not supplied)
1 plate at the right HV side on the bottom of the enclosure for the HV cables for connections
from the bottom
as an option, a HV cables clamping system shall be provided when the cables are coming from
the bottom
Electrical Protection
3.7.1 Protection relay
The installation must have a protection relay to protect the transformer from:
•
•
•
•
overload,
short circuits (internal or external),
earth faults,
overflow.
3.7.2 MV surge arresters
It is advisable to check that the installation will not be subjected to over voltage of any kind
(atmospheric or switching over voltage).
If there is a risk, the transformer should be protected by phase-earth surge arresters installed directly
on the MV connection terminals (top or bottom).
Phase-earth surge arresters are absolutely essential in the following cases:
•
•
If the lightning impact level Nk is greater than 25. The risk of direct or induced atmospheric
over voltage is directly proportional to Nk.
During the occasional switching (less than 10 operations a year) of a transformer with a weak
load, or during a magnetisation period.
They are highly recommended in the following case:
•
If the substation is supplied by a network including overhead parts, then a cable which is longer
than 20 m (for example, an overhead-underground network).
3.7.3 RC filters (repetitive switching operations)
If the installation is likely to be subjected to repetitive switching operations (e.g. connected with a
process), it should be protected from the resulting surges, which are particularly harmful to the
transformer.
The ideal solution for protecting the installation completely from these surges (with high frequency
oscillations), consists in fitting an RC damping filter between the phases and the earth.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 15
Section 4 - High Tension Components Specification
This RC filter should be placed as close as possible to the transformer’s primary terminals.
This gets rid of the high frequency phenomenon, and limits voltages at the transformer terminals.
The filter should consist of 3 units, 50 Ohm resistors (of the RWST type), and 3 units, 0.25 µF
capacitors, insulation level 24 kV.
It may be placed either in a separate metal enclosure or, preferably, inside the metal enclosure of the
transformer.
3.8
Climatic and Environmental Classifications
These transformers will be of climatic Class C2 and of environmental Class E2 as defined in
Appendix B of HD 464 S1: 1988 / A2 : 1991. C2 and E2 Classes will be indicated on the rating plate.
The manufacturer must produce a test report from an official laboratory for a transformer of the same
design as those produced.
The tests must have been performed in accordance with Appendix ZA and ZB of CENELEC HD 464
S1: 1988 / A3: 1992.
3.9
Fire Behaviour Classification
These transformers will be of Class F1 as defined in article B3 of CENELEC HD 464 S1: 1988 / A2:
1991. F1 Class will be indicated on the rating plate.
The manufacturer must produce a test report from an official laboratory on a transformer of the same
design as those produced and on the same transformer which have initially passed the here above
Climatic and Environmental tests. This test must have been performed in accordance with Appendix
ZC of CENELEC HD 464 S1: 1988 / A3: 1992.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 16
Section 4 - High Tension Components Specification
4.0 11 kV CABLE SPECIFICATION
4.1
Types of Cables
The cable to be supplied under this specification shall be manufactured and tested in accordance with
BS 6480: Part 1: 1969 and shall be of XLPE type to a voltage rating suitable for continuous operation
on a 11 kV, 3-phase, 50 Hz distribution system.
4.2
Cable Trench
Cable trenches shall be 750 mm deep. The trenches shall be of sufficient width to enable provision of
adequate spacing between cables but in any case shall not be less than 450 mm wide. Trenches shall
be kept as straight as possible and shall have vertical sides which shall be timbered where necessary
so as to avoid subsidence and damage. The bottom of the trenches shall be firm and of smooth
contour and any other objects likely to damage the cable sheathing shall be removed. The material
excavated from the trenches shall be placed or removed so as to prevent nuisance or damage to
adjacent areas or buildings. The trench excavation and filling in shall be so executed that all roads,
walls, sewers, drains, pipes, cables, structures etc. shall be reasonably secured against risk of
subsidence damage. Provision shall be made, during excavation and until interim restoration has been
completed, for reasonable access of persons and vehicles to the areas of buildings adjacent to the
trenches. The Electrical Contractor shall provide pumps and other appliances for the necessary
pumping required for the disposal of water so as to prevent any risk of the cables and other materials
to be laid in the trenches being detrimentally affected. Where necessary, bailing shall be provided.
Where trenches pass from a footway to a roadway or at other position where a change of level is
necessary, the bottom of the trench shall rise or fall gradually.
4.3
Cable Ducts
At road crossings, sewerage pipe crossing, water pipe crossings, paved areas, concrete areas and
where specified cables shall be protected by galvanized steel pipes buried to a depth of 900 mm
below finished ground level. The pipes shall be of heavy duty type, complying with BS 1387 and
complete with screwed and socket joints. Unless otherwise specified the pipes shall be 150 mm in
diameter. Where it is necessary to cross drains, culverts or similar obstruction which is too deep for
the cables to be buried below, galvanized steel pipes as specified above shall be provided. The pipes
shall be supported at each end in a concrete block and shall project through the blocks into the ground
at a depth of at least 750 mm. All ducts shall be extended at least 600 mm beyond paved areas,
concrete areas, drains, road crossing, pipe crossings etc. Cable entering a building shall be protected
by pitch fiber ducts of 150 mm diameter, complying with BS 4108, completed with bend pieces,
buried to a depth of 900 mm and encased with 75 mm of concrete all round. The ducts shall be
installed with a gradient so as to drain away any water in the ducts. All ducts passing through walls
shall be effectively sealed and made water-tight. The number of cables installed in each duct shall be
such that the space factor shall not be less than 60%. A draw wire shall be provided for each duct.
Unless specified to be provided by others, the above galvanized steel pipes and/or pitch fiber ducts
shall be provided.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 17
Section 4 - High Tension Components Specification
4.4
Cable Marker
Cable markers shall be of heavy duty reinforced concrete construction. The cable marker shall be of
trapezoidal block with 100 mm square top face, 150 mm square bottom face and 400 mm in height.
The top face shall be indented with bold lettering `H.V.' and directional sign indicating the
direction/directions of the cable route.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 4 - 18
Section 5 - Motor Specification
Section 5
Motor Specification
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 5 – Motor Specification
Page
Section 5 – Motor Specification
1.0
Submersible Motor
5-1
2.0
Surface Mounted Motors
5-2
2.1
General
5-2
2.2
Indoor Type Motor
5-3
2.3
Outdoor Type Motor
5-3
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
i
Section 5 - Motor Specification
SECTION 5 – MOTOR SPECIFICATION
1.0 SUBMERSIBLE MOTOR
The electric motor shall be a 3 phase, squirrel-cage induction type running at not more than 1,500 rpm
suitable for 50 cycles, 415 V and complying with BS 5000 or BS 4999. The motor shall be built for
submersible operation, Class IP68 according to IEC. The motor shall be able to withstand a minimum
depth of 20 m submergence.
The motor stator shall be shrunk fit into an air-filled watertight stator casing. Externally mounted
screws that may cause leakage into the motor shall not be used. The motor casing and sealing
arrangements shall be designed waterproof to Class IP68.
Motor bearing and shaft shall all the loads induced by the short-coupled i.e. pump impeller and mixer
propeller.
The motor shall be capable of operating continuously with full load without overloading throughout
the operation. It shall be able to tolerate voltage variations of up to ±10% of the rated voltage of 415
V without overheating. The motor shall operate at voltage imbalance of up to 2% between phases and
current imbalance of up to 4% between phases.
The motor shall start by direct on-line, star-delta, auto transformer, soft starter and variable speed
drive in accordance with the size of the motors.
The motor shall run continuously or intermittently with a maximum of 15 evenly spaced starts per
hour. The motor shall be tested in accordance to IEC 34-1.
The stator shall be moisture-resistant and triple-varnished and shall be insulated to Class F (IEC
publication) capable of withstanding temperatures up to 155oC (to confirm the spec.), however the
maximum temperature rise shall not exceed 80oC.
The motor shall have a terminal box capable of sealing off the junction box completely from the
stator casing to prevent leakage through the junction box into the stator housing. The cable entry
water-seal design shall be such that the cables are sealed off by a compressible rubber bush and fitted
with cable strain relief clamps. The design shall preclude specific torque requirements to ensure a
water tight and submersible seal. Epoxies, silicon resin or other secondary sealing systems shall be
used.
The stator shall incorporate three thermal switches connected in series for monitoring purposes.
Thermal sensors shall protect the stator from overheating in the case of asymmetric phase loading or
voltage, continuous dry run or excessive temperatures in the medium itself. For motor rating of 37
kW and below, a minimum motor protection shall incorporate a leakage sensor at the seal chamber
and a PT 100 or better in the stator winding. For motor rating of 37 kW and above, a full monitor
motor protection shall be incorporated. The leakage sensor shall be located at the upper terminal area,
lower motor area and seal chamber. The thermal sensor shall be located at the upper and lower
bearing housing and stator winding.
Power to the motor is supplied by one or several flexible cable(s) that connect to the motor through a
sealed inlet to a connection box. The cable is supplied to specified length by the manufacturer.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 5 - 1
Section 5 - Motor Specification
The cables contain a sufficient number of leads for motor start and operation as well as for control
impulse transmission.
The motor is dimensioned for cooling submergence in the pumped liquid. For dry installation, cooling
is provided by liquid circulating in a cooling jacket or by other means of heat transfer into the
pumped liquid.
2.0 SURFACE MOUNTED MOTORS
2.1
General
Electric motors shall be manufactured and shop tested to BS 4999 and BS 5000. Motors shall be
tropicalised 3 phase squirrel cage induction type. Both indoor and outdoor surface mounted motors
shall comply with IEC 34-1 Electrical and IEC 72-1 Mechanical Specification. The motor shall be
tested in accordance to IEC 34-1. 3-phase cage rotors shall be robust in design and construction and
capable of running continuously for prolonged periods with minimum attention.
Motor bearing and shaft shall carry all the loads induced by the short-coupled i.e. pump impeller and
mixer propeller.
The motor shall be manufactured in a one-piece stator frame casing. The feet shall be integrally cast
into the stator frame. For most frames the terminal box shall be mounted on the top as standard. The
terminal box can be rotated so that cables can be connected from the right and left.
All shaft diameters shall be machined to IEC 60072 for ease of fitting, removing or securing fitments,
a tapped hole in the drive end shaft.
Tolerances on main performances parameter shall comply with IEC 60034-1 specifies allowable
tolerances for efficiency, power factor, speed, locked rotor torque, pullout torque, starting current and
moment of inertia.
Ball bearings shall be used for motors having aluminium frames. Motors with cast iron or fabricated
steel frames shall have ball or roller bearings. Ball bearings shall be grease lubricated. Working
thrust loads shall not be placed on the motor bearing.
The motor fan shall be made of light aluminum alloy.
The motor shall start by direct on-line, star-delta, auto transformer, soft starter and variable speed
drive in accordance with the size of the motors. Motors shall be equipped with their own starters and
shall run at not more than 1,500 rpm, unless specified otherwise. Motor starters shall be fitted with a
no-volt release and thermal overload in each phase. Motors and their associated starters shall be
suitable for operation on a 415 V, 3-phase and 50 Hz supply.
Motors shall be capable of continuously running and shall be able to tolerate voltage variations of up
to ± 10% without overheating in accordance with BS 5000 S1 designation. The motor shall operate at
voltage imbalance of up to 2% between phases and current imbalance of up to 4% between phases.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 5 - 2
Section 5 - Motor Specification
PT 100 or better shall be built into the motor windings for motors above 3.75 kW. It shall act either to
give an alarm or to stop the motor.
The stator shall be moisture-resistant and triple-varnished and shall be insulated to Class F (IEC
publication) capable of withstanding temperatures up to 155oC, however the maximum temperature
rise shall not exceed 80oC, Class B.
2.2
Indoor Type Motor
The types of motor enclosures and degree of protection for electric motors to be used in different
areas shall be as follows: Totally Enclosed Fan Cooled Type (TEFC) to be used in damp and dusty indoor areas and shall have
a service factor of not less than 1.15 or greater.
2.3
Outdoor Type Motor
The types of motor enclosures and degree of protection for electric motors to be used in different
areas shall be as follows: Motors shall be with Class F insulation and IP55 enclosure. Motors shall be single speed Totally
Enclosed Fan Cooled (TEFC) and rated for continuous use. It shall have a service factor of not less
than 1.15 or greater.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 5 - 3
Section 6 - Low Voltage Cable Specification & Installation
Section 6
Low Voltage Cable Specification &
Installation
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 6 – Low Voltage Cable Specification & Installation
Page
Section 6 – Low Voltage Cable Specification & Installation
1.0
2.0
3.0
4.0
Type of Cable and Application
6-1
1.1
Type of Cables
6-2
1.2
Application of Cables
6-2
Cable Installation
6-2
2.1
Cable Laid Direct In Ground
6-2
2.2
Submerged Cable
6-3
Requirements
6-4
3.1
Colours
6-4
3.2
Conductors
6-4
Cable Trench
6-4
4.1
Cables in Pre-Cast Concrete Trenches
6-5
4.2
Cables on Walls and Under Floor Slabs
6-5
4.3
Surface Cabling
6-5
5.0
Cable Ducts
6-6
6.0
Cable Termination and Jointing
6-6
7.0
Cable Accessories
6-6
7.1
Metallic And Non-Metallic Conduits
6-7
7.2
Cable Trays
6-7
7.3
Clipped Direct
6-7
7.4
Cable Fixings
6-8
7.5
Cable Glands
6-8
7.6
Cable Marker
6-8
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
i
Section 6 – Low Voltage Cable Specification & Installation
SECTION 6 – LOW VOLTAGE CABLE SPECIFICATION &
INSTALLATION
1.0 TYPES OF CABLE AND APPLICATION
1.1
Type of Cables
(i)
PVC/SWA/PVC CABLE
Cable shall be manufactured and tested in accordance with MS 274 or BS 6346 and shall have high
conductivity plain copper stranded conductors insulated with PVC suitable for a voltage of 600/1000
V laid together and bedded with PVC, armoured with galvanised steel wires and sheathed with PVC.
(ii)
XLPE/SWA/PVC CABLE
Cable shall be manufactured and tested in accordance to BS 5467 or IEC 60502 and shall have high
conductivity plain copper stranded conductors, insulated with cross-linked polyethylene (XLPE),
suitable for a voltage of 600/1000 V laid together and bedded with extruded PVC, armoured with
galvanised steel wires and sheathed with PVC.
(iii)
XLPE/AWA/PVC CABLE
Cable shall be manufactured and tested in accordance to BS 5467 or IEC 60502 and shall have high
conductivity plain copper stranded conductors, insulated with cross-linked polyethylene (XLPE),
suitable for a voltage of 600/1000 V laid together and bedded with extruded PVC, armoured with
aluminium wires and sheathed with PVC.
(iv)
XLPE/PVC CABLE
Cable shall be manufactured and tested in accordance to BS 5467 or IEC 60502 and shall have high
conductivity plain copper stranded conductors, insulated with cross-linked polyethylene (XLPE),
suitable for a voltage of 600/1000 V laid together and bedded with extruded PVC and sheathed with
PVC.
(v)
PILCDSTAS CABLE
Cable shall be manufactured and tested in accordance with BS 6480 Part 1 and shall have high
conductivity plain copper stranded conductors, insulated with strong long fibre paper, uniform in
texture, free from metallic particles, mass impregnated with non-draining insulating oil compound
suitable for a voltage of 600/1000 V, lead alloy sheathed, double steel type armoured and served.
Refer to Appendix 01 – Abbreviation.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 6 - 1
Section 6 – Low Voltage Cable Specification & Installation
1.2
Application of Cables
Cables shall be segregated into the following categories: (i)
Power (less than 1,000 V phase to phase)
•
PVC/PVC multicore cable to BS 6346 installed in floor ducts or conduits.
PVC single core non-sheathed (600/1 000 V) to BS 6231 installed as internal wiring within
switchgear and control assemblies.
PILCDSTAS Cable shall be manufactured and tested in accordance with BS 6480 Part 1 and
shall have high conductivity plain copper stranded conductors, insulated with strong long
fibre paper, uniform in texture, free from metallic particles, mass impregnated with nondraining insulating oil compound suitable for a voltage of 600/1000 V, lead alloy sheathed,
double steel type armoured and served.
•
•
(ii)
Instrumentation/telemetry
•
PE/PSCR/OSCR/PE/SWA/PVC. Plain annealed multistranded copper conductors, solid
polyethylene insulation with aluminium-mylar pair screening including drain wire, with
collective aluminium mylar screen including drain wire, solid polyethylene bedded steel wire
armour with an outer sheath of flame retardant PVC. PVC sheath to be blue colour for
intrinsically safe circuits, black for AC and DC non-intrinsically safe circuits, 300/500 V
grade to BS 5308: Part 1, Type 2.
(iii)
Control Digital
•
PE/OSCR/PE/SWA/PVC.
Plain annealed multi stranded copper conductors, solid
polyethylene insulation collective aluminium mylar screen including drain wire, solid
polyethylene bedded steel wire armour with an outer sheath of flame retardant PVC. PVC
sheath to be blue colour for intrinsically safe circuits, black for AC and DC non-intrinsically
safe circuits, 300/500 V grade to BS 5308: Part 1, Type 2.
2.0 CABLE INSTALLATION
All cables shall be handled, laid and installed according to BS 7671, cable manufacturer's
recommendations and ERA Reports by using proper installation equipment and tools. Cables shall be
laid in a manner such that any electrical interference between cables shall not have a detrimental
effect on the life and operation of equipment installed within the installation.
As a general rule the following minimum clearances shall be adhered to wherever practical. There
shall be a minimum separation of 300 mm between all cables.
Unless otherwise permitted by the JPP/IWK Representative no cable shall be laid and covered up in
the absence of the JPP/IWK Representative. Cables shall be installed in such a way that the minimum
bending radius is not reduced when installed or during installation. Cables shall not be installed in
ambient temperatures below that recommended by the cable manufacturer.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 6 - 2
Section 6 – Low Voltage Cable Specification & Installation
The minimum internal bending radius of the cable shall not be less than 12 times the overall diameter
of the cable. Wherever cables are cut, the ends shall be immediately sealed in an approved manner
unless; it is intended to proceed with cable jointing for termination straight away.
For groups of more than one cables laid in the same trench, they shall be spaced by the horizontal
clearance between adjacent cables of at least twice the overall diameter of the adjacent largest size
cables. Cables grouped together shall have insulation capable of withstanding the highest voltage
present in the group.
Where practical a separate cable support system shall be provided for power and non-power cables.
Where this is not practical a separation of 150 mm shall be maintained between power and non-power
cables when run on the same support system.
In order to make economic use of the cable support system, cables shall be arranged in groups of 50
mm maximum overall diameter. These groups shall be securely tied to the cable support system at
intervals not exceeding 900 mm for horizontal runs and 300 mm intervals on vertical runs.
Refer to Appendix 01 – Abbreviation.
2.2 Submerged Cable
Cable shall be manufactured and tested in accordance with DIN VDE 0282-4. They fulfill the
requirements specified for cables used in contaminated water. The cables shall have a high
conductivity copper finely stranded, Class 5 to DIN VDE 0295 and IEC 60228 insulated with special
rubber compound, EPR (Ethylene Propylene Rubber) base suitable for a voltage of 450/750 V
sheathed with: (i)
Single-sheath
This is provided with all single-core cables and for all multicore cables with conductor crosssections up to and including 10 mm2. Special synthetic rubber compound, minimum
specifications as for compound types EM2 and 5GM3 to DIN VDE 0207-21. Thickness to
DIN VDE 0282-4.
(ii)
Two-sheath
This is to provide for multicore cables with conductor cross-sections of 16 mm2 and more.
Inner sheath shall be of a special rubber compound, EPR base, and minimum specifications
as for EM1 and GM1b to DIN VDE 0207-21. Sheath thickness to DIN VDE 0282-4. Outer
sheath shall be of a special sythentic rubber compound, minimum specifications as for
compound types EM2 and 5GM3 to DIN VDE 0207-21. Sheath thickness to DIN VDE 02824.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 6 - 3
Section 6 – Low Voltage Cable Specification & Installation
3.0 REQUIREMENTS
3.1
Colours
The colour coding shall be in accordance to IEEE latest edition. The following shall serve as a
guide: i.
ii.
iii.
iv.
3-phase
Single phase or DC
Earth
Control
3.2
Conductors
Red, Yellow and Blue
Red and Black
Green/Yellow
Blue (DC), Red (AC)
Copper conductors shall comply with BS EN 60228. The size of conductors shall be made reference
to Section 1 – Low Voltage Switchboard and Components Specification and Section 3 – Small Power
and Lighting.
4.0 CABLE TRENCH
Unless otherwise specified, cable trenches shall be 750 mm deep. The trenches shall be of sufficient
width to enable provision of adequate spacing between cables but in any case shall not be less than
450 mm wide.
Trenches shall be kept as straight as possible and shall have vertical sides which shall be protected
where necessary so as to avoid subsidence and damage. The bottom of the trenches shall be firm and
of smooth contour and any other objects likely to damage the cable sheathing shall be removed.
The material excavated from the trenches shall be placed or removed so as to prevent nuisance or
damage to adjacent areas or buildings.
The trench excavation and filling in shall be so executed that all roads, walls, sewers, drains, pipes,
cables, structures etc. shall be reasonably secured against risk of subsidence damage. Provision shall
be made, during excavation and until interim restoration has been completed, for reasonable access of
persons and vehicles to the areas of buildings adjacent to the trenches.
The trench excavation shall provide pumps and other appliances for the necessary pumping required
for the disposal of water so as to prevent any risk of the cables and other materials to be laid in the
trenches being detrimentally affected. Where necessary, bailing shall be provided. Where trenches
pass from a footway to a roadway or at other position where a change of level is necessary, the
bottom of the trench shall rise or fall gradually.
Refer to Appendix B – Laying of Underground Cable Drawing
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February 2007
Sec 6 - 4
Section 6 – Low Voltage Cable Specification & Installation
uPVC cable protective covers shall be of polyvinylchloride without plasticiser type with specific
density between 1.37 g/cm3 to 1.42 g/cm3. The uPVC cover shall be resistant to aggressive soils and
of dimension 150 mm wide and 1,000 mm long.
The covers shall be single coloured orange and top side shall be embossed with standard danger sign
and bold letters “BAHAYA! KABEL ELEKTRIK DI BAWAH”.
The covers shall be provided with male and female interlocking device. An orange coloured, multistrand nylon rope of minimum 6 mm diameter shall be laid at along the trench to identify the cable
route.
Refer to Appendix B – Laying of Underground Cable Drawing
4.1
Cables in Pre-Cast Concrete Trenches
Cable tray specification shall be made reference to 7.2 – Cable Trays.
In the case of single core cable, non-ferrous saddle shall be used.
The cable tray shall be supported by mild steel brackets. The bracket shall be hot dipped galvanised.
All brackets shall be securely fastened with steel raw bolts and nuts.
All cable tray joints shall be bridged by means of tinned copper tape of dimension not less than 25
mm x 3 mm. All saddles for cables on cable trays shall be installed by bolts, washers and nuts. All
cable tray tees, intersection units, adaptor units etc. shall be factory manufactured.
4.2
Cables on Walls and Under Floor Slabs
Cable tray specification shall be made reference to 7.2 – Cable Trays. Cable run on walls and under
floor slabs shall be mounted on cable trays. Method of installation of the cables shall be in accordance
with Method 11 and 12 of BS 7671 Table 4A. The construction and finished of the cable trays and the
way of installation of the cables on the cable trays shall be made reference to 4.1 – Cable in Pre-Cast
Concrete Trenches.
The cable trays shall be suspended from floor slabs by hangers or mounted on wall by brackets at 600
mm interval. The material and finishes of the hangers, brackets and other suspending and supporting
structures shall be made reference to 4.1 - Cable in Pre-Cast Concrete Trenches.
Where cable trays pass through floors or fire resistant walls, the surrounding hole shall be sealed to
full thickness of the floor or wall with non-hygroscopic fire-resisting material of minimum 2 hour fire
rating approved by Jabatan Bomba Dan Penyelamat Malaysia.
4.3
Surface Cabling
Surface cabling shall be carried out with PVC insulated PVC sheathed cables of 300/500 V grade to
MS 136 and 600/1000 V grade to MS 274. The conductors shall be of stranded plain annealed copper
Electrical Works Specifications
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February 2007
Sec 6 - 5
Section 6 – Low Voltage Cable Specification & Installation
to MS 69 and MS 280. The insulation shall be suitable for continuous operation at a maximum cable
temperature of 70 0C and comply with MS 138.
The cables shall be run on the surface of the walls, floor slabs and in the ceiling spaces. The cables
shall be secured by lead alloy saddles.
Cables crossing metal surface shall be enclosed in PVC conduit. Saddles shall be fixed by brass nails
and spaced at not more than 150 mm apart.
5.0 CABLE DUCTS
At road crossings, sewerage pipe crossing, water pipe crossings, paved areas, concrete areas, concrete
areas and where specified, the cables shall be protected by galvanised steel pipes. The pipes shall be
of heavy duty type, complying with BS 1387. Unless otherwise specified the pipes shall be 150 mm in
diameter.
Spare cable ducts of 150 mm diameter galvanized steel pipes shall be provided at all road crossings.
Spare ducts to be provided with draw wires and temporarily sealed to prevent ingress of water.
Cable entering a building shall be protected by heavy duty galvanised steel pipes complying with BS
1387 of 150 mm diameter completed with bend pieces.
6.0 CABLE TERMINATION AND JOINTING
Cable termination and jointing is not encouraged, however if required, all such termination and joints
shall be provided for installations of more than 1,000 m of cable. All joints and termination shall have
prior approval before commencements of works.
A plastic laminated plate engraved with details such as size of cable, number of core, date of
commissioning, date of jointing, length of cable, distance of cable joint and etc. shall be securely
fixed near the termination.
The heat shrinkable termination materials used shall be supplied in a complete kit to suit various sizes
of cable and to provide stress control, non-tracking and environmentally sealed termination. It shall
consist of high permittivity, high resistivity, heat shrinkable, stress control, UV stable, non-tracking
polymeric materials and heat activated sealant to prevent ingress of moisture and contamination.
The type of cable boxes, compound and jointing materials used shall be factory manufactured. Unless
otherwise specified cast iron joint boxes shall be used, and all jointing kits shall be approved by the
JPP/IWK Representative before joints being carried out.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 6 - 6
Section 6 – Low Voltage Cable Specification & Installation
7.0 CABLE ACCESSORIES
7.1
Metallic and Non-Metallic Conduits
Steel conduits shall be of galvanized, heavy gauge, Class B, screwed type complying with MS 275-1,
IEC 60614-1, IEC 60614-2-1 and IEC 60423. All steel conduit fittings shall comply with MS 275-2,
IEC 61035-1 and IEC 61035-2-1.
The steel conduits shall be fitted with brass bushes at the free ends and expansion devices. The ends
of each length of steel conduit shall be properly reamed. The termination to the distribution boards,
consumer units, switchgears and outlet boxes shall be effected by brass type smooth-bore bushes.
For cable size 25 mm and below junction box specification shall be made reference to Section 1 –
Low Voltage Switchboard and Components Specification. For cable 35 mm and above, junction box
shall be 2.3 mm thickness electro-plated mild steel sheet with 90 µm paint thickness. It shall be
treated to prevent corrosion. The junction box shall be able to accommodate the cable size and the
bending radius shall be taken into consideration.
For non-metallic conduits and fittings, they shall be of rigid high impact PVC and approved by
Jabatan Bomba Dan Penyelamat Malaysia for use in electrical installation.
The colour of the conduit for concealed wiring shall be of orange. Unless otherwise for purposes of
identification or distinguishing from another services, white coloured conduit shall be used for
surface wiring. Rigid high impact PVC conduits shall comply with IEC 60614-1, IEC 60614-2-2 and
IEC 60423 and fittings shall comply with MS 67, IEC 61035-1 and IEC 61035-2-2.
All fittings for the rigid high impact PVC conduits shall be made and supplied by the same
manufacturer for the rigid high impact PVC conduit. The ends of each length of rigid high impact
PVC conduit shall be properly reamed. The termination to the distribution boards, consumer units,
switchgears and outlet boxes shall be effected by adaptors and lock-rings. Flexible metallic and nonmetallic conduits shall comply with IEC 60614-1 and IEC 60614-2-5 and its fittings complying with
IEC 61035-1 and IEC 61035-2-3.
Steel saddles shall be used for steel conduits. Unless otherwise specified, steel conduits and steel
fittings shall be used.
7.2
Cable Trays
Cable trays shall be fabricated from perforated hot dip galvanised sheet steel complete with all
necessary bends, tee pieces, adaptors and other accessories. Minimum thickness for the sheet steel of
the perforated hot dipped galvanised cable trays shall be 2.0 mm.
All supports, hangers and structures shall be of hot dipped galvanised type, robust in construction and
adequately installed to cater for the weights of the cables and trays supported on them so that cable
trays and cables will not sag. The cable tray spacing shall be 300 to 600 mm depend on the size and
numbers of the cables.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 6 - 7
Section 6 – Low Voltage Cable Specification & Installation
Fixing clips and cleats for cables on trays shall be installed by means of bolts, washers and nuts. All
tees, intersection units, adaptor units etc. shall be the type manufactured by the cable tray
manufacturer unless otherwise approved.
7.3
Clipped Direct
All cable hangers, clips, cleats and saddles shall be of an approved type and appropriate to the type
and size of cable installed.
7.4
Cable Fixings
Ties and strapping shall be made of hot dip galvanized steel bends installed at intervals of every 600
mm. All bolts and nuts used shall be of hot dip galvanized steel.
7.5
Cable Glands
Glands shall generally be of the mechanical double compression hexagon type. Earth continuity of
brass glands shall be assured. This may be achieved by the rigid clamping of the armour within the
gland and the intimate contact between the threaded components of the gland and the equipment.
Glands for single core cables shall be constructed from non-magnetic materials.
Each gland shall be installed complete with a proprietary non-ferrous lock nut to secure the gland
body to the equipment where the entry hole is plain, i.e. not tapped.
7.6
Cable Marker
Cable markers shall be of heavy duty reinforced concrete construction. The cable marker shall be of
trapezoidal block with 100 mm square top face, 150 mm square bottom face and 400 mm in height.
The top face shall be indented with bold lettering `L.V.' and directional sign indicating the
direction/directions of the cable route.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 6 - 8
Appendix A – Abbreviation
Appendix A
Abbreviation
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 6: Appendix A – Abbreviation
APPENDIX A
ABBREVIATION
PVC
SWA
XLPE
AWA
PILCDSTAS
OSCR
PSCR
PE
Polyvinyl Chloride
Steel Wired Armoured
Cross Linked Polyethylene
Aluminium Wired Armoured
Paper Insulated Lead Covered Double Steel Tape Armoured and Served
Overall Screened
Pair Screened
Polyethylene
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
App: A - 1
Appendix B – Laying of Underground Cable
Appendix B
Laying of Underground Cable
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
GROUND SURFACE
GROUND SURFACE
EARTH
uPVC CABLE
PROTECTIVE
COVER
SAND
150mm
76mm
150mm
SAND
150mm
CABLE
76mm
750mm
750mm
EARTH
76mm
76mm
CABLE
450mm/min
450mm/min
a) SINGLE CABLE
b) DUAL CABLE
(RUNNING PARALLEL)
Note:
Actual width of cable trench will depend
On number of cables laid.
TYPICAL DRAWING FOR LAYING OF UNDERGROUND
CABLE DIRECT TO GROUND
GROUND SURFACE
750mm
EARTH
150mm
914mm
150mm
152mm
SAND
CABLE
152mm
GI PIPE
450mm/min
Note:
Number of GI pipes laid
TYPICAL DRAWING FOR LAYING OF UNDERGROUND
CABLE USING G.I PIPE
Section 7 – Earthing, Lightning and Surge Protection
Section 7
Earthing, Lightning and Surge
Protection
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Section 7 – Earthing, Lightning and Surge Protection
Page
Section 7 – Earthing, Lightning and Surge Protection
1.0
2.0
Common Earth Termination Network
7-1
1.1
Requirements
7-1
1.2
Specifications
7-2
1.2.1 Copper Tape Conductor
7-2
1.2.2 Ground Electrodes
7-2
1.2.3 Exothermic Welding
7-2
1.2.4 Inspection Chamber
7-3
1.2.5 Main Ground Bar
7-3
Surge Protection
2.1
Requirements
7-3
2.2
Specifications
7-4
2.2.1 Surge Protection Device
7-4
2.2.2 Sub Circuit – Circuit Connected To Sensitive Equipment
E.G. Compact Plc, Plc.
7-5
3.0
Lightning Protection
7-5
3.1
Requirement
7-5
3.2
Installation
7-6
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
i
Section 7 - Earthing, Lightning and Surge Protection
SECTION 7 – EARTHING, LIGHTNING AND SURGE
PROTECTION
1.0 COMMON EARTH TERMINATION NETWORK
1.1
Requirements
The purpose of the Common Earth Termination Network (CETN) is to eliminate potential difference
between two or more earthing system within a facility, providing equipotential earthing system for all
services, thus providing:
•
•
•
•
Adequate path for earth fault return
To ensure personnel safety from electrical shock hazard
To prevent hazardous discharge of static electricity and fire risk
To provide low impedance and resistance path for high frequency current discharge
It is important for the CETN to able to last for a minimum of 25 years, hence, it is important that all
components required/necessary for the completion of CETN be of high quality.
All services earth and metallic part of structure must be properly bonded to the CETN.
CETN, when completed, shall form the common earth termination network system for:
•
•
•
•
•
•
Direct Strike Lightning Protection System (LPS)
Electrical Distribution
Genset (Frame & Neutral)
Supply intake (TNB)
Electronics
Telecommunications
The interconnection of all ground points shall be by means of flat bare copper tape conductor with
dimension of not less than 25 mm (width) × 3 mm (thickness). Flat bare copper tape conductor
produces much less inductance compared to that of copper stranded cable.
The copper tape conductor shall be bonded to ground points by means of Exothermic Welding only.
Any other type of mechanical clamps, brazing is not acceptable as these method are subjected to
corrosion, loosening, mechanical failure, electrical failure and disconnection.
Main ground bars (MGB) shall be provided at suitable locations for termination of all
metallic/conductive surface e.g. metallic enclosures, earthing of equipment(s) or surge protectors.
MGB shall be wall mounted at a pre-specified height for termination convenience. Good, strong and
permanent connections by means of Exothermic Welding must be provided for the electrically
continuous connection of MGB and external/underground CETN. Each MGB shall have a minimum
of two tinned copper conductor interconnection between MGB and external CETN.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 7 - 1
Section 7 - Earthing, Lightning and Surge Protection
Dimension & sizes of MGB, conductor shall be as per table below: Prospective earth fault currents
(I) for 1s duration
40 kA < I ≤ 50 kA
Main Ground Bar
50 mm x 6 mm
MGB & CETN interconnecting
conductor
2 mm x 25 mm x 3 mm
The following standards & regulations shall be adhered to for the works: •
•
•
•
•
BS 6651
BS 7430
IEEE Std 81.2
IEEE Std 837
UL/ANSI
Lightning & Common earth termination network
Earthing
Measurement of Resistance/Impedance of Earth System
Qualifying Permanent Connection
Electrical Safety Standard
The earth resistance for the Common Earth Termination Network (CETN) shall be 1 Ohm (Ω) or less.
1.2
Specifications
1.2.1 Copper Tape conductor
Flat bare copper tape conductor shall be in compliance to BS 1432 for soft drawn conductor. Copper
tape conductor shall have dimension not less than 25 mm (width) × 3 mm (thickness). Copper tape
conductor shall be buried at a minimum of 600 mm depth.
1.2.2 Ground Electrodes
Auxiliary ground electrode shall be of the molecularly copper bonded steel ground electrodes.
Copper clad and jacketed type earth electrodes are not acceptable. Copper coating thickness on
ground electrode shall be minimum 0.254 mm in accordance to UL & ANSI specifications.
The ground electrode shall not be less than 14.2 mm (5/8”) in diameter and 1,800 mm (6’) in length.
The ground electrode shall be extended to required electrode length using high strength electrode
coupling.
The ground electrodes shall have a minimum driven depths of not less than 3,600 mm and equally
spaced (using the < 2 × L formula as per BS 7430) to maximize each points’ potential.
1.2.3 Exothermic Welding
Exothermic welding materials shall be in compliance to UL for approvals of grounding and bonding
products. Exothermic welding connections must also be tested to guidelines in accordance to IEEE
Std. 837.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 7 - 2
Section 7 - Earthing, Lightning and Surge Protection
1.2.4 Inspection Chamber
Each ground electrodes point shall be provided with a heavy duty type inspection chamber with
removable cover. The inspection chamber shall have a minimum dimension of 345 mm (width) ×
345 mm (length) × 210 mm (depth). Lifting hook shall be provided for removable cover.
1.2.5 Main Ground Bar
The Main Ground Bar (MGB) shall be of high conductivity copper bar. MGB shall have a minimum
of 6 × M8 hole for termination of earth conductors. All termination to MGB shall be using stainless
steel bolts & nuts and proper/suitable compression lug.
The MGB shall not be less than 450 mm (length) × 50 mm (width) × 6 mm (thickness).
The MGB shall be properly isolated from structure wall using high resistance insulators.
A transparent protective cover of sufficient thickness and dimensions with label engraved and marked
in red legibly with words “Main Earthing Terminals Safety Electrical Connections – Do Not
Remove” shall be installed to cover full length of the MGB.
Two earthing conductors of tinned copper tae of dimension as indicated in table above shall be
provided to connect the MGB to external CETN. The earthing conductors shall be protected, where
necessary, by means of galvanized steel conduit and buried in the ground at a depth of not less than
450 mm below finished ground level.
Interconnecting conductors between MSB/SSB and MGB shall be by similar earthing conductors to
those between MGB & CETN. These conductors shall be mechanically protected using PVC
rectangular channel flushed with the floor slab.
2.0 SURGE PROTECTION
2.1
Requirements
The lightning surge protection devices (SPD) shall be installed at specific locations for specific
equipments and panels as per design, drawing and engineer’s specifications.
The SPD shall be installed with care to minimize the amount of let through voltage into equipments.
The SPD shall conform to various international standards for its surge handling capability, let-through
voltage and short circuit current handling capability.
All materials, equipment and components for a safe & durable lightning SPD must be UL certified.
Standards & Regulations
IEC 62305-4 Protection Against Lightning Part 4 – Electrical & Electronic Systems within Structure
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 7 - 3
Section 7 - Earthing, Lightning and Surge Protection
ANSI/IEEE C62.41 High Energy Lightning & Switching Standard
IEC 61643 Surge Protection Devices connected to low-voltage distribution systems
UL1449 Electrical Safety Standard
2.2
Specifications
2.2.1 Surge Protection Device
The surge protection device (SPD) shall be compatible with the system it is protected and shall
provide phase-to-neutral, phase-to-earth and neutral-to-earth protection for either single phase or
three phase power supply system. The normal operating voltage of the SPD for phase-to-neutral
connection shall be 240 V and the maximum operating voltage is 275 V. SPD for phase-to-earth and
neutral-to-earth connections shall be rated at 415 V and the maximum operating voltage of 475 V.
The leakage current shall not exceed 3.5 mA. Unless otherwise specified, the type of SPD to be
installed with respect to the location of switchboard shall be as in Table 1 below: -
Location of switchboard
Main switchboard or
Sub switchboard
receiving energy from
licensee or other
building
Switchboard and/or
distribution board
receiving energy from
main switchboard and
or Sub switchboard
located in the same
building
Location Category
C
B
Exposure Level
High
High
Peak Discharge
Current (8/20 µs test
waveform)
40 kA
20 kA
Peak Transient Let
≤ 800 V (20 kV, 1.2/50
≤ 600 V (6 kV, 1.2/50
Through Voltage for
all modes
µs and 10 kA, 8/20 µs
test waveforms)
µs and 3 kA, 8/20 µs
test waveforms)
Table 1 - Types of Surge Protection Device
The peak transient let-through voltage or voltage protection level for all modes (phase-to-neutral,
phase-to-earth and neutral-to-earth) shall be as in Table 1 above. Unless otherwise specified, the SPD
shall be of the type complying with BS 6651 and/or IEC 61024-1 and IEC 61643-1, IEC 61312-1 and
IEC 61312-3.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 7 - 4
Section 7 - Earthing, Lightning and Surge Protection
The surge protection device shall incorporate continuous indication of its protection status, via full
protection present, reduced protection - replacement required and no protection - failure of protection.
The connecting leads shall be as short as possible and not more than 1,000 mm in length, and shall be
tightly bound together over throughout the whole length. Unless otherwise specified, four-pole
moulded case circuit breaker or fuses of rating as recommended by the SPD manufacturer shall be
provided to enable full isolation of SPD from the system for maintenance.
2.2.2 Sub Circuit – circuit connected to sensitive equipment e.g. Compact
PLC, PLC.
SPD shall be installed as secondary protection for sensitive electronics equipments to minimize the
risk & danger of lightning surge current (let through voltage of MSB SPD). The power SPD shall
have a minimum 16 kA 8/20µs surge handling capability.
The SPD shall be equipped with series LC filter to ensure low let-through voltage of not more than
600 V when tested using 3 kA 8/30µs wave shape as per IEC 61643-1 Class II.
Status indication of SPD shall be of either mechanical flag or LED.
Surge protection shall be provided at the main incoming supply of the panels/switchboards where
there is electronic devices are connected or those with incoming breaker ratings of 100 A and above.
Protection shall be provided between live and earth as well as neutral and earth.
Surge protection units shall be designed for multiple applications (as lightning consists of a number
of pulses) and components shall be able to withstand the vibration caused by the pulses. Surge
protection devices shall be designed so that alarm outputs can be retrofitted whenever required. The
total surge rating in a 8/20 microsecond waveform shall not be less than 100 kA.
The let-through voltage shall not exceed 900 V. The surge protection device shall comply with the
following standards: •
•
•
•
•
IEC - 801 - 5
IEC - C -62.41 - 1991
BS EN 60099-1:1994
IEC 587 Category E
IEC 1024 - 1 (Zone O)
3.0 LIGHTNING PROTECTION
3.1
Requirement
The lightning protection system (LPS) network shall comprise of the following (but not limited to):•
•
•
•
Aluminium air terminal
Aluminium tape roof & down conductor
Aluminium tape saddle
Bi-Metallic connector
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 7 - 5
Section 7 - Earthing, Lightning and Surge Protection
•
•
•
Copper tape down conductor
Copper Plate type test clamp
Earthing network termination system
The LPS network shall comply with the latest applicable provisions and recommendations of: •
•
•
3.2
BS 6651
BS 7430
IEC 62305
Code of practice for Protection of Structures Against Lightning
Code of practice for Earthing
Code of practice for lightning protection system
Installation
Air terminations shall be firmly secured by suitable mounting mast, fixing bolts, screws and clamps
to establish good electrical continuity from air terminal to downconductor and to ensure they are
securely held in position under the influence of mechanical stresses during the passage of lightning
currents.
All roof air terminations shall be of aluminium type material.
The number of downconductor shall be in accordance with BS 6651. Downconductors shall be
brought down from roof air termination using the least number of loops as possible.
The aluminium downconductor shall be terminated at approximately 1,800 mm from finish floor level
as indicated in the design drawing. Thereafter, Bi-Metallic connector shall be used to connect the
aluminium downconductor to copper earth termination conductor.
The copper earth termination conductor shall be embedded within the wall. The copper earth
termination conductor shall be routed directly to ground point and terminated.
Termination of the copper earth conductor to ground points (copper ground rods) shall be by means
of Exothermic Welding connection for a permanent & long lasting termination as well as to prevent
loosening & disconnection.
The earth termination network shall consist of copper ground rods conductor with minimum driven
depths of not less than 3,600 mm and equally spaced (using the < 2 × L formula as per BS 7430) to
maximize each points’ potential. Each ground points (ground rods) shall be interconnected using bare
copper tape conductor buried underground with buried depth of not less than 600 mm.
A complete lightning protection network shall be provided in accordance with MS 939:1984.
All exposed non-conducting metal parts in the plant shall be bonded to earth. The lightning protection
system shall comply with BS 6651 and shall take the form of a closed network and down conductors
using aluminium strip.
Conductors shall be fixed to the roof of any buildings in an approved manner. Waterproof barriers
shall not be penetrated. Where fixings are required to pass through waterproof membranes, the
approval of the Technical Committee of the Sewerage Services Department shall be obtained prior to
the commencement of work.
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 7 - 6
Section 7 - Earthing, Lightning and Surge Protection
Final connection to the earth electrode shall be made using aluminium strip installed in high impact
heavy gauge PVC Class D conduit for below ground level installation.
Wherever possible natural contact between dissimilar metals shall be avoided. Joints between copper
and aluminium conductor shall be made as follows:
•
•
•
•
Contact area of copper shall be tinned
Contact area of aluminium shall be cleaned and coated with an oxide resisting paste
Make off joint using copper rivets or purpose made clamps
Joint to be liberally coated with bitumen paint and totally encased in a heat shrink sleeve
Electrical Works Specifications
Issue 01 / Revision 01
February 2007
Sec 7 - 7