262413_Low_Voltage_Switchboards_TechSpecs_JULY_2012.pdf

26 24 13: TECHNICAL SPECIFICATIONS: LOW VOLTAGE SWITCHBOARDS.

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JULY 2012 (100% FINAL)

Low Voltage Switchboards

Technical Specs

This document contains proprietary information and is protected by Copyright laws and should hence not be copied or published, in part or in whole, in any form or manner without the written approval of the Integrated Bureau for Engineering & Consultations (IBEC). The document shall be used for viewing and

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1. GENERAL

1.1. DESCRIPTION:

1.1.1. This section specifies the furnishing, installation and connection of Low Voltage Switchboards.

1.2. SUBMITTALS

1.2.1. Sufficient information, clearly presented, shall be included to determine compliance with drawings and specifications.

1.2.2. Include electrical ratings, dimensions, mounting details, materials, wiring diagrams accessories and weights of equipment. Complete nameplate data including manufacturer’s name and catalog number.

1.2.3. Two complete sets of documentation will be supplied with the panels. Each set will include but will not be limited to, set of drawings (single line diagram, layout, internal layout, wiring and control diagrams), catalogs, test certificates, product data sheets, operation, maintenance, and installation instructions.

1.2.4. Supplier shall submit a detailed settings table showing the setting ranges of all protections provided (whether built into the switching devices or provided separately) and the factory default settings of such protections

1.2.5. Supplier shall submit current-time characteristics for all supplied circuit breakers

1.2.6. Bidder must submit a detailed quotation supported by necessary drawings and a clear list of deviations and/or alternatives

1.2.7. Successful bidder must have a complete and detailed set of drawings approved by the client’s consultant before commencing to manufacture.

1.2.8. Supplier shall submit a detailed settings table showing the setting ranges of all protections provided (whether built into the switching devices or provided separately) and the factory default settings of such protections. The settings will be based on a Short Circuit Study and Protective Device Coordination Study completed using professional grade power system analysis software. The settings will guarantee coordination of circuit breakers and other protections as far upstream as the in plant Medium Voltage Switchgear and as far down stream as the MCC (Motor Control Center) and MCP (Motor Control Panel) level.

1.2.9. The Switchboards will be warranted against defects of manufacture for a period not less than 18 months from delivery or 12 months from commissioning and start up.

2. PRODUCTS

2.1. General Provisions:

2.1.1. Switchgear shall be of the metal enclosed, factory assembled, with busbar construction for power distribution. Enclosures shall be free standing (unless otherwise indicated on single line diagram) steel structures.

2.1.2. Switchboard, circuit breakers, and all other power or control devices will comply with the latest relevant IEC standards including but not limited to:

2.1.2.1. IEC 60439: Low-voltage switchgear and controlgear assemblies

2.1.2.2. IEC 60529: Degree of protection provided by enclosures

2.1.2.3. IEC 60947: Low-voltage switchgear and controlgear

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2.1.3. Type tested design (or partial type tested design) verification should be made available at the time of bidding.

2.1.4. The Distribution system adopted will be TN-S.

2.1.5. All equipment must be able to function correctly and safely when connected to the power supply of the site. i.e. 380V, 3-phase, 50Hz, with earthed neutral.

2.1.6. All electrical components will be sized for continuous 24 hrs/day duty at rated capacity at 40 degrees centigrade ambient temperature (or ambient temperature indicated on design single line diagrams).

2.1.7. The panels will be warranted against defects of manufacture for a period not less than 18 months from delivery or 12 months from commissioning and start up.

2.2. Enclosure:

2.2.1. The panels shall be made of sheet steel of thickness not less than 1.5mm with doors and structure being reinforced to insure rugged and safe construction.

2.2.2. A removable cable gland plate made of sheet steel of not less than 3 mm in thickness will be provided.

2.2.3. The panels will be electrostatically powder painted with the manufacturer’s standard color.

2.2.4. All internal parts of the panel will be either painted or galvanized without compromising the earthing of the panels.

2.2.5. All cable entry in equipment must be through a gland of suitable size. All remaining openings must be sealed

2.2.6. The panels will be of the floor mounted design (unless indicated otherwise on the design single line diagram) with provision for fixing the panel to a base frame.

2.2.7. All compartments shall have removable hinged doors on the front. Free-standing panels will be provided with removable rear covers to facilitate rear access of the busbar and other components.

2.2.8. Front plates will be provided to prevent any contact with any live parts when the panel door is open. Front plates (mirror) provided to prevent any contact with live parts when the panel door is open shall in no way prohibit the adjustment of protections and circuit breaker trip units with the front plate in place. In other words all adjustments and settings should be possible without need for removing the front plate.

2.2.9. All switchgear where live parts will be exposed in case the door is opened must be with a key lock.

2.2.10. The panels will be designed and manufactured to withstand symmetrical short circuit currents for

1 second.

2.2.11. The degree of protection of the panels will be minimum IP42 for indoor applications and IP54 for outdoor applications (unless otherwise indicated on the design single line diagram).

2.2.12. All internal switchgear components must be finger touch proof (IP2X) or above. Panels shall have removable transparent covers protecting all components inside the panel operating above 50V to earth and which are not "Touch Safe (IP2X)”

2.2.13. Switchboards shall be of such dimension that adequate space is available for maneuvering and connecting the incoming and outgoing cables.

2.2.14. Switchboards shall have a form of separation Form 4.

2.2.15. For MCC Panel, the Form of Separation is Form 3.

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2.2.16. Cable entry for all outgoing units shall be from the bottom/top as per indications shown on the electrical rooms furnishing drawing. Cable entry for the incoming lines will be either from the top or bottom as per the indications on the design single line diagrams.

2.2.17. Generally, provision will be made for terminals for connection of cables with sizes and numbers per phase as indicated on the single line diagram in such a way that no more than one cable is connected to the circuit breaker terminal or two cables are connected back-to-back on any extension terminal.

2.2.18. Capacitor banks will be supplied with Comfort type capacitor units rated at 440V (for 400V supply) complete with discharge resistors.

2.2.19. All enclosures and metal parts that do not carry any current must be connected to the ground.

2.3. Circuit Breakers and Switching Devices:

2.3.1. All circuit breakers will be rated for at least the symmetrical 3-phase short circuit current indicated on the design single line diagram. The short circuit breaking capacity will be on basis of Service short circuit capacity not Ultimate short circuit rating (except for miniature circuit breakers which will follow whatever indications are shown on the single line diagrams).

2.3.2. All circuit breakers will be rated for at least the symmetrical 3-phase short circuit current indicated on the design single line diagram WITHOUT depending on any cascading effects. The dependability on cascading to achieve the required breaking capacity is prohibited unless it is specifically mentioned on the design single line diagram or it is approved in writing by the client’s consultant.

2.3.3. Frame size of circuit breakers shall be properly selected by vendor to guarantee correct operation of the circuit breaker when considering:

2.3.3.1. The IP (Index of Protection) of the panel

2.3.3.2. The Form of Separation of the panel

2.3.3.3. The ambient temperature

2.3.3.4. The requirements for Protective Device Coordination

2.3.3.5. Installation inside particular type of switchgear

2.3.4. All circuit breakers or power switching devices which will have their cable/busbar connection terminals exposed shall be provided with “Insulated Terminal Covers” to completely isolate both terminals of the switch from human touch.

2.3.5. No circuit breakers above 63A shall be of the miniature type. Circuit breakers above 63 A shall be molded case or air (power) circuit breakers. Below 63A, circuit breakers shall be provided of types as indicated on the design single line diagram.

2.3.6. All circuit breakers 1600A and above shall have an adjustable definite time setting facility for the instantaneous (short circuit) trip.

2.3.7. All circuit breakers 1000A and above shall be provided with at least 2NO and 2NC spare auxiliary contacts for future use by customer.

2.3.8. All circuit breakers above 250A shall have an electronic (or microprocessor) type trip unit. The circuit breakers will be provided with electronic (or microprocessor) trip units with long time, short time, and instantaneous settings available.

2.3.9. All circuit breakers installed in the Main Low Voltage Switchboard of a Source (Transformer, This document contains proprietary information and is protected by Copyright laws and should hence not be copied or published, in part or in whole, in any form or manner without the written approval of the Integrated Bureau for Engineering & Consultations (IBEC). The document shall be used for viewing and

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Generator, or Mains Entrance) shall be provided with units with long time, short time (adjustable for both current and time), and instantaneous (adjustable) settings available.

2.3.10. All circuit breakers 1600A and above shall be provided with a facility to switch off the instantaneous trip.

2.3.11. Ground fault protection will be provided whenever indicated on the single line diagram. However, supplier shall recommend the use of Ground Fault Protection whenever deemed necessary (based on the values of single line to ground fault current levels calculated from the short circuit study and the trip C/Cs of the supplied circuit breakers) to guarantee protection against indirect contact.

2.3.12. All circuit breakers and switching devices are assumed to be of the Three (3) Pole construction unless otherwise indicated on the design single line diagram.

2.3.13. The short time withstand of any Load Switch (Disconnecting Switch) will be coordinated with the trip time of the upstream protective device to ensure the Load Switch will withstand the prospective short circuit current expected to pass through for the duration of the trip time of the upstream protective device.

2.3.14. Generally circuit breakers will be of the fixed type. Circuit breakers will be of the withdrawable type only if indicated on the design single line diagram.

2.3.15. Generally Circuit breakers will be manually operated unless otherwise indicated on the single line diagram. However, for circuit breakers acting as incomings from a mains supply, and for circuit breakers involved in any redundancy or maneuvering scheme, such breakers will be equipped with motorized operation, and an electrical means of switching the circuit breaker on. If motorized operation of the circuit breaker is provided, the breaker aside of being equipped with an electrical method for closing will also be provided with a shunt trip as a means for electrical tripping of the circuit breaker.

2.3.16. All Circuit breakers which will be involved in any automatic control function and which are equipped with motor operation for the purpose of this control, shall be of the Air Circuit Breakers type.

2.3.17. Any main (incoming circuit breaker) of a switchboard fed from a mains supply (power transformer or otherwise), shall be equipped with motor operation, shunt trip, under voltage trip, closing coil, under/over voltage protection, phase sequence and phase failure protection, and Automatic-Zero- Manual control for return to service after restoration of mains voltage.

2.3.18. Any panel fed from a power generator will be provided with a complete Automatic Transfer Switch (ATS) circuit with full Automatic and Manual options. Unless it is indicated on the design single line diagram that ATS function is achieved using contactors, the main (incoming circuit breaker) fed from the generator will be equipped with motor operation, closing coil, under voltage trip, and shunt trip. Vendor will provide any additional equipment and/or components deemed necessary for the correct operation and protection of the ATS option.

2.3.19. Any panel fed from a power generator will have its generator side incoming circuit provided with at least the following additional protections:

2.3.19.1. Reverse Power Protection

2.3.19.2. Under Voltage Protection

2.3.19.3. Over Voltage Protection

2.3.19.4. Under Frequency Protection

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2.3.19.5. Over Frequency Protection

2.3.19.6. Phase Failure Protection

2.3.19.7. Phase Sequence Protection

2.3.20. In the situation where any switchboard is supplied from multiple sources, the incoming circuit breakers will be provided with Trip auxiliary contacts and all other means and accessories necessary to prohibit the connection of one supply to a bus section whose main supply was disconnected due to a fault on that bus section.

2.3.21. Coordination between any circuit breaker and series contactor will be Coordination Type 2.

2.3.22. Unless otherwise indicated, all Contactors will be rated for AC3 duty class for motor applications and AC1 duty class for lighting applications and appropriate duty class for capacitor switching applications.

2.3.23. All devices used for switching and/or protection of capacitors will allow for 10% current up-rating due to voltage variations & 30% current up-rating due to harmonic currents.

2.3.24. All MCC starter units >30kW must incorporate an ammeter on their front panel.

2.3.25. For Motor Control Centers (MCC) "Phase Failure" protection must be implemented.

2.3.26. For Motor Control Centers (MCC) "Phase Sequence" protection must be implemented.

2.3.27. Drives less than 100HP (75kW) MAY be DOL (Direct On Line). All drives over 100HP must be

Star/Delta or soft start energized.

2.3.28. Provision shall be made in Motor Starters so that the local Safety Disconnect Switches (SDS) of motors will trip the motor control circuit when the SDS is disconnected.

2.3.29. Whenever SPACE with a certain rating is indicated on the design single line diagram, a circuit breaker or switching device WILL NOT be supplied, however, physical empty space will be provided for future installation of a circuit breaker or switching device of the indicated rating. Also, the main busbar and back plates (supports or otherwise) should be punched and adapted completely for the future installation of the indicated device without the need of any additional works on site.

2.4. Labeling:

2.4.1. All circuit breakers must be labeled with the load name using engraved type labels which will be provided to identify the switching circuits.

2.4.2. All internal components and devices must be labeled using engraved labels.

2.4.3. All external labels will be of the engraved type with suitable dimension and attached by screws or rivets. The use of adhesive is unacceptable for external labels.

2.4.4. The label lettering shall be of black color on a light colored background. The opposite (white lettering on dark background) shall not be acceptable.

2.4.5. Each Switchboard shall be provided with an engraved type external label with the following data included on the label:

2.4.5.1. Name of switchboard

2.4.5.2. Fed from

2.4.5.3. Rated Voltage/Frequency/Current

2.4.5.4. Number of phases + Neutral + Earth

2.4.5.5. Short Circuit Level.

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2.5. Busbars:

2.5.1. For Partially Type-Tested Panels, the busbar system shall be type tested for short circuit withstand (1s), bracing, temperature rise. The relevant certificates and/or catalog verification of such testing shall be made available at the time of bidding. The type testing verification of busbar cross-section suitable for satisfaction of the short circuit withstand, ambient temperature conditions, and permissible temperature rise shall be also be made available prior to approval of the panels.

2.5.2. The switchboard will be provided with high quality copper busbars with current ratings as indicated on the design single line diagram.

2.5.3. The busbar will be properly de-rated for an ambient temperature of 40ºC (or higher if indicated otherwise on the design single diagram).

2.5.4. All busbars provided inside the switchboard will be made of high grade copper that is treated to ensure protection against oxidation and smearing under the thermal conditions of normal operation.

2.5.5. All busbars installed inside the switchboard shall be of quality and craftsmanship that provides a busbar with no sharp edges.

2.5.6. Manufacturer will make provision for adequate bracing (support) and spacing of busbar systems to guarantee the busbar construction will withstand the symmetrical short circuit indicated on the design single line diagram. Bracing shall be verified by standards and/or partial type test verification.

2.5.7. Switchboards shall be provided with a suitable earth bar and neutral bar with adequate provision for the connection of a circuit protective conductor for each outgoing line.

2.5.8. The neutral bus will be same cross-section of phase bus.

2.5.9. The earth busbar will be at least half the size of the neutral bar.

2.5.10. The copper ground bus will be at least 5mm by 50mm and will extend the length of each switchboard with provision at each end for the customer to attach a suitable earthing conductor.

2.5.11. Reduction of the main busbar (and/or vertical busbar) cross-section is not acceptable. The cross-section of the main busbar shall be the same for the whole length of the switchboard. The cross-section of the vertical busbars (if applicable) will be the same for the whole length of the cubicle (column)

2.5.12. All power distribution (main) inside the panels will be done using copper busbars. Distribution using wire and copper bridges is not allowed. Links from the main busbar to power devices shall be copper busbar links for all currents above 250A. For outgoings 250A and below cable links (to the main busbar) of adequate cross-section may be used.

2.5.13. Any busbar links from a switching device to the main busbar that may rotate around a single point of fixation if enough force is applied shall be provided with additional means (points) of fixation to prevent this rotation under the influence of the mechanical forces of a short circuit. The additional fixation shall ensure the distances between the phases of the link are maintained under all circumstances.

2.5.14. Busbar links from a switching device to the main busbar that are longer than 200mm shall be covered by heat shrinkable insulation on all 3 phases. The heat shrinkable insulation may be applied to only the middle phase after approval from the owner/consultant.

2.5.15. Extension copper terminals (links) will be provided on the cable side terminal of a circuit breaker

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(or any switching device) to facilitate the connection of the number and size of cables indicated on the design single line diagram if such a connection is not directly possible on the circuit breaker terminal. Such links shall be fully separated by solid insulation between the phases adequate to guarantee the prevention of any accidental and/or vermin bridging of the phases.

2.5.16. Whenever and wherever applicable, manufacturer will provide suitable accessories and means to prevent electrolytic reaction between copper and aluminum contacting.

2.5.17. All busbars will be clearly marked R-S-T or L1-L2-L3

2.5.18. All cable ends inside switchgear will be clearly marked R-S-T or L1-L2-L3

2.6. De-rating:

2.6.1. All circuit breakers, power circuit devices, and busbars will be properly de-rated for the design ambient temperature.

2.6.2. All circuit breakers, power circuit devices, and busbars will be properly de-rated for installation in respective switchgear.

2.6.3. All circuit breakers, power circuit devices, and busbars will be properly de-rated for the Degree

(Index) of Protection (IP) respective of the panel.

2.6.4. All circuit breakers, power circuit devices, and busbars will be properly de-rated for the Form of

Separation (Segregation) respective of the panel.

2.7. Auxiliary Circuits and Wiring:

2.7.1. All wiring will be terminated and clearly marked and numbered.

2.7.2. Terminal blocks will be used to complete all auxiliary interconnections.

2.7.3. Terminal blocks will be numbered and will be grouped according to function.

2.7.4. Means shall be provided to indicate whether or not the incoming supply line is energized. It is preferred to use three indicating lamps (R-S-T) for this purpose.

2.7.5. For each of the incoming and outgoing switching devices that are electrically operated (On-Off) indicating lamps and (On-Off) push buttons will be provided on the external door of the switchboard.

2.7.6. Control & data cables must be in separate conduit (ducts) than power cables.

2.7.7. The minimum size for power wiring will be 2.5mm2. The minimum size for control wiring will be

1.5 mm2. The minimum size for wiring of current circuits fed from the secondary of a current transformer will be 2.5 mm2.

2.7.8. Minimum earthing conductor size will be 16mm2.

2.7.9. All cables will be continuous and will not be spliced or joined.

2.7.10. Cables with solid conductors are not allowed. All cables must be stranded.

2.7.11. All wires shall be of the stranded flexible type. No single strand (solid) wires are allowed.

2.7.12. All derived control voltages will be obtained by using an isolating transformer with appropriate rating and ratio.

2.7.13. Control wiring shall be ferruled with plastic wire markers (numbers) at both ends.

2.7.14. All control wires shall carry same marking as used in schematic wiring diagrams.

2.7.15. No more than one conductor is to be terminated on one terminal.

2.7.16. Color coding of wires will be as per the following

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Phase Power Black (L1, L2, L3) DC Power Black (+, -) Power Neutral Dark Blue Earth Green/Yellow DC Control Light Blue AC Control Red

2.7.17. Inside the panels no device will be blocking or obscuring another device.

2.7.18. All connections must allow ample room for their removal.

2.7.19. Wire terminations will be crimped not bare wire or soldered. Spade crimps must be used. Eyelet type crimps are not to be used.

2.7.20. All outgoing cable connections will be via Power Terminal Blocks.

2.8. Instrumentation:

2.8.1. Three ammeters, one voltmeter with seven position selector switch, and one digital kW/kWH meter will be provided on the incoming feeder whenever indicated. All measuring instruments will be suitably rated and will be of at least class 1.5. One digital multi-meter in place of the above instruments will also be acceptable.

3. EXECUTION

3.1. INSTALLATION

3.1.1. Install the switchboard in accordance with the NEC, as shown on the drawings, and as recommended by the manufacturer.

3.1.2. Mount switchboard on concrete slab. Unless otherwise indicated, the slab shall be at least 4 inches [100mm] thick. The top of the concrete slab shall be approximately 4 inches [100mm] above finished floor. Edges above floor shall have 1/2 inch [12.5mm] chamfer. The slab shall be of adequate size to project at least 8 inches [200mm] beyond the equipment. Provide conduit turnups and cable entrance space required by the equipment to be mounted. Seal voids around conduit openings in slab with water- and oil-resistant caulking or sealant.

3.2. Testing:

3.2.1. All routine tests according to IEC will be attended by client representatives and it’s consultant in factory before delivery of the panels. The switchboards will be subjected to full routine tests as per IEC requirements. Such tests will include and will not be limited to: Insulation resistance test, dielectric test, high voltage power frequency test (on main and auxiliary circuits), full electrical and mechanical function tests, and testing of protective relays by current injection (circuit continuity and validation of CT ratio by primary injection and trip settings by secondary injection).

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3.3. Training:

3.3.1. Training shall be provided for client personnel on the procedures for start up, testing and operation. Three operator's manuals shall be provided showing full installation and operating instructions.

End of Specification