specification of lt

7/28/2019 Specification Of LT

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Core Green Sugars and Fuels Pvt. Ltd.

TECHNICAL SPECIFICATIONS OF SUGAR UNIT

LT TECHNICAL SPECIFICATIONS

1. LT PCC AND MCC BOARDS

Power Distribution Panels and Sub-Power Distribution Panels shall be suitable for operation

on 3 Phase/single phase, 415 volts, 50 cycles, neutral grounded at transformer. All Power

Distribution panels shall be by a CPRI approved, reputed manufacturer.

Distribution panels shall comply with the latest Relevant Indian Standards and Electricity

Rules and Regulations.

Specific requirement of each panel has been covered under single line diagram.

1.1 CONSTRUCTION FEATURES

All Main Power Distribution panels shall be designed for Totally Type Tested as per IEC

60439-1 for indoor/outdoor installation, dead front, floor mounting/wall mounting type and shall

be form 3-b construction. The Power Distribution Panels shall be undergone internal ARC

Test for different type of feeders, especially smaller rating feeders. The Power Distribution

panels shall be totally enclosed modular construction completely dust and vermin proof and

shall be with hinged doors, Neoprene gasket, padlocking arrangement and bolted back. All

removable/ hinged doors and covers shall be grounded by flexible standard connectors.

Power Distribution panel shall be suitable for the climatic conditions as specified in Special

Conditions. Steel sheets used in the construction of Power Distribution panels shall be 2.5 mm

for frame, 1.6 mm for doors and 2 mm for other sheet metal works and shall be folded andbraced as necessary to provide a rigid support for all components. Joints of any kind in sheet

metal shall be seam welded, all welding, slag shall be rounded off and welding pits wiped

smooth with plumber metal. The general construction shall confirm to IS-8623-1977 (Part-1)

for factory built assembled switchgear & control gear for voltage up to and including 1100 V

AC.

All panels and covers shall be properly fitted and square with the frame, and holes in the

panel correctly positioned. Fixing screws shall enter into holes tapped into an adequate

thickness of metal or provided with wing nuts. Self threading screws shall not be used in the

construction of Power Distribution panels. A base channel of 75 mm x 40 mm x 5 mm thick

shall be provided at the bottom for floor mounted panels. Minimum clearance of 275mm shall

be provided between the floor of Power Distribution panels and the lowest unit.

Power Distribution panels shall be of adequate size with a provision of spare switchgear as

indicated on the Single Line Diagram. Switches shall be arranged in multi-tier. Knockout

S.V. Engineers & Consultants Page 1


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holes of appropriate size and number shall be provided in the Power Distribution panels inconformity with the location of cable/conduit connections. Removable sheet steel plates shall

be provided at the top to make holes for additional cable entry at site if required.

Every cabinet shall be provided with Trifoliate or engraved metal name plates. All panels shall

be provided with circuit diagram engraved on PVC sheet. All live accessible connections shall

be shrouded and minimum clearance between phase and earth shall be 20 mm and phase to

phase shall be 25 mm.

1.2. BUS BAR CONNECTIONS

Bus bar and interconnections shall be of high conductivity electrolytic aluminum / copper alloy

complying with requirement of grade E 91 E of IS: 50821981 and of rectangular cross

section suitable for carrying the rated full load current and short circuit current without

overheating of phase and neutral bus bars and shall be extendable on either side. Bus bars

and interconnections shall be insulated with heat shrinkable sleeve of 1.1 KV grade and shall

be colour coded. Bus bars shall be supported on glass fiber reinforced thermosetting plastic

insulated supports at regular intervals to withstand the force arising from in case of short

circuit in the system. All bus bars shall be provided in a separate chamber and all connections

shall be done by bolting. Additional cross sectional area to be added to the bus bar to

compensate for the holes. All connections between bus bars and breakers shall be through

extended solid copper strips of proper size to carry full rated current and to receive thealuminium bus bar through bimetallic strip / washer.

1.2.1 TEMPERATURE - RISE LIMIT

Unless otherwise specified, in the case of external surface of enclosures of bus bar system

which shall be accessible but do not need to be touched during normal operation, an increase

in the temperature rise limits of 25 C above ambient temperature shall be permissible for

metal surface and of 15 C above ambient temperature for insulating surfaces as per IS

8623(Part-2) 1993.

Continuous earth bus sized for prospective fault current shall be provided with arrangement

for connecting to station earth at two points. Hinged doors/ frames shall be connected to earth

through adequately sized flexible braids.

1.2.2 STANDARDS



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The design, manufacture and performance of equipment covered by this specification shallconform to the relevant Standards.

The design, manufacture and testing of the various equipment covered by this specification

shall comply with the latest issue of the following standards :

IEC-144 : Degree of protection of enclosure for low voltage switchgears and control gearIEC-185 : Current TransformersIEC-186 : Potential TransformersIEC-255 : Electrical RelaysIEC-269 : LV FusesIEC-439 : LV switchgears and control gear assemblyIEC-947 : LV switchgears and control gearIS:722 : AC Electricity metersIS:1248 : Specification for direct acting electrical indicating instrumentsIS:2147 : Degrees of protection provided by enclosures for low voltage switch gear andcontrol gearIS:2705 : Specification for current transformerIS:3231 : Electrical relays for power system protectionIS:5082 : Material data for aluminium busbarsIS:5578 : Guide for making of insulated conductorsIS:8623 : General requirement for factory built assembly upto 1000 VIS:8828 : Electrical accessories - circuit breakers for over current protection for house holdand similar installationsIS:9224 : Low voltage fusesIS:10118 : Code of practice for selection, installation and maintenance of switchgear andcontrol gear not exceeding 1000 VIS:11353 : Guide for uniform system of marking and identification of conductors andapparatusterminalsIS:12021 : Control transformer for switchgear and control gear for voltages not exceeding1000V AC

IS:13947 : LV Switchgears and Control gear

1.3 COMPARTMENTS

1.3.1 CABLE COMPARTMENTS

Cable compartment of adequate size shall be provided in the Power Distribution panels for

easy clamping of all incoming and outgoing cables entering from the top/bottom.

Adequate supports shall be provided in cable compartment to support cables.



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1.3.2Circuit Breaker Compartments

Spring actuated and gravity operated safety shutters shall be provided for isolating the

busbars and other live parts when the breaker is completely withdrawn. The design of

compartment shall be such as to prevent movement of vermin from a particular circuit breaker

compartment to any other portion of the panel when the breaker is withdrawn and the

compartment door is closed.

The circuit breaker compartment enclosure shall be IP31 with the circuit breaker in position or

withdrawn from the compartment.

The circuit breaker compartment shall be fully draw out, ie., bus side and outgoing power and

control connections shall be through drawout contacts (it shall be possible to drawout thewithdrawable trolley without having to unbolt or unscrew any power and control connections).

Suitable guides shall be provided to facilitate easy withdrawal of the trolley. All identical feeder

compartments shall be interchangeable without having to carryout modifications.

The drawout breaker shall be earthed by means of a scraping earth system of silver plated

copper such that the earth connection is broken after the breaker main contacts disengage

during withdrawal and the earth connection is made before the main contacts engage during

insertion.

The earth connection shall remain connected in "test" and "isolated" positions also.

The draw-out compartments shall have the following interlocks:

Compartment doors shall be interlocked against opening when breaker is in closed or ONcondition. However, it shall be possible to bypass this interlock for inspection purposes. It shall not be possible to push "in" a drawn out circuit breaker in closed condition orwithdraw a circuit breaker in closed condition. It shall be possible to operate a circuit breaker only in the defined "Full In" or "Service" and"test" position inside the panel. It shall not be possible to operate the breaker in intermediateposition while inserting or withdrawing a circuit breaker or while in "Full Out" position insidethe panel. It shall be possible to open / close the circuit breaker in test position bypassing the closinginterlocks. All the circuit breakers shall be provided with an TNC switch for local electrical operation anda Local / Remote selector switch for selecting the mode of operation.The breaker shall be of draw-out type and shall be suitable for motor / manual spring chargedclosing.Mechanical Castell key type interlocks shall be provided between feeders, wherever specified.Electrical interlocks shall also be deviced, wherever specified.Transducers in the ACB module shall be mounted in control compartment, not in powercompartment.



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ON/OFF/TRIP feed back signals and ON / OFF control signals shall be arranged to connectwith DCS system.

1.3.3 Feeder Modules

The module shall comprise of the following :- Feeder MCCB with 3 poles and neutral link- Set of cluster type LED lamps for ON / OFF- Meters, as specified- Current transformers- Terminal blocks, interconnection bars / wires, ferrules etc., as per requirement

Doors shall be mounted on adjustable and removable pin type concealed hinges and soarranged that unit doors may be removed without disturbing the unit doors above or below.The MCCB operating handles shall be capable of being padlocked in the `OFF' position.For the purpose of standardisation, similar components in the switch board shall be of thesame make / brand, identical and interchangeable.Only the operating handle of the MCCB shall be accessible for operation with the related doorclosed.The doors shall be interlocked with the associated load break switch so that the door can beopened only when the switch is in the de-energised (off) position and the doors shall not becapable of being closed with the switch in the energised (on) position. Provision shall also beavailable to defeat the interlock.Each compartment shall have suitable nameplate, which shall be fixed on the cover in distinctcolour to designate the feeder number, feeder designation, current rating and HP/kW of therelated equipment.

ON / OFF indication signals to be arranged to connect with DCS system.

1.3.4 Motor Feeder Starter Modules

The starter modules shall comprise of the following :- Feeder switch with 3 pole MCCB, as applicable- Air-break contactor(s)- Bi-metallic over load relay below 100 HP and microprocessor based Motor protection relaysfor 100HP and above ratings..- 4A MCB for the control circuits.- Set of cluster type LED lamps for ON / OFF / TRIP.- Timer set table upto 60 sec. for star-delta starters.- Analog type Ammeter shall be provided on door for the ratings above 10HP and asspecified.- Current transformers for metering and protection.



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ON / OFF /TRIP indications signals and ON / OFF control signals to be arranged to connectwith DCS system.

- All starters rated above 75 kW shall be provided with an auxiliary contactor to transfer theON/OFF signal from DCS.

- The SLD shown are indicative and intended for general guidance of the panel supplier, forinterfacing with DCS. The supplier shall develop detailed schemes for each motor feeder.- Supplier shall select the rating / burden of control transformer, semi-conductor fueses, PTs,CTs, Range of transducers, ammeter and speed indicators suitably.- Space heater supply shall be made available for all feeders rating 30kW and above.- Terminal blocks, interconnection bars / wires, ferrules etc., as per requirement.Only the operating handle of the MCCB/MPCB, Local/remote, DCS selector switches andAmmeter selector switches shall be accessible for operation with the related doors closed.The MCCB ratings and over load relays shall be suitably coordinated with the main contactorrating to meet type 2 requirement in accordance with IS:13947-4.Suitable AC3 duty rating of the contactor shall be selected.Heavy Duty Contactor shall be provided for all the fans, Conveyors and Blower Motor feeders.

1.3.5 Marshalling Compartments

A common Marshalling compartments / cabinets, as an extension for the switchboards shall beprovided, for connection of multi-core cables from DCS racks. A Marshalling Compartment of

adequate size shall be provided in each 415V PCC / MCC / Distribution Board (common forall feeders in a particular switchboard) to house the interposing relays, contact multiplyingrelays. The terminal blocks shall be mounted in such a way that FIELD terminal blocks /terminations and DCS terminal blocks / terminations are coming on either side (Front and Rear).All inter-panel wiring between the individual modules, marshalling compartment shall be throughmetallic troughs with cover. The inter panel wiring between the individual modules and themarshalling compartment shall be done only with screened cables.

Marshalling cabinets shall house terminal blocks and transducers for connection to 415V PCC,Auxiliary Switchboard and MCC compartments / DCS racks, as shown in the drawings. However,local push button stations and other field instrument cables shall be directly connected to therespective motor feeder compartments.

The terminal block arrangement shall be arranged as below :

All digital inputs (DIs) from different feeders to be terminated at a separate array of terminalblocks. All digital outputs (DOs) from different feeders to be terminated at a separate array ofterminal blocks. All analog inputs (AIs) from different feeders to be terminated at a separate array of terminalblocks.All terminal blocks shall be identified with the respective feeder names.



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The communication port of all the Tri Vector Meters / kWH meters in the 415V PCC shall beconnected in series through Screened, twisted pair cable of 0.5 Sq. mm. and a single pointconnectivity shall be provided in the marshalling compartment for hooking up these signals tothe Energy Management System. However, there shall be an independent terminal blockindividually for all the Tri Vector Meter / kWH meter.

1.3.6 Control Supply

Control Supply bus shall be of 240V for all the panel and this supply to be tapped from Mainsfrom the incoming side of the Panel incomer.There shall be two control transformers in each panel with DP MCBs on incoming side andwith a changeover switch at outgoing side of transformers to provide redundant control supply.

2 nos. 20A 2pin power sockets with 16A switch shall be provided in each panel formaintenance purpose.

Control bus supply failure signal shall be arranged to connect it to DCS.

1.4 Low Voltage Air circuit-breakers

1.4.1 Conformity with Standards

ACBs used in low voltage panels should conform to the International Standards IEC 60947,EN 60947, CEI EN 60947 and IEC 61000 and conform to the relevant EC directives:Low voltage directive (LVD) No. 73/23 EECElectromagnetic Compatibility Directive (EMC) No.89/336 EEC

1.4.2 Functional characteristics

- The circuit-breakers must have a rated service voltage of 690V a.c. and a rated insulationvoltage of 1000V.- The circuit-breakers must have a rated impulse withstand voltage Uimp 12kV.- The circuit breakers shall enable short circuit protection with Icu 50kA up to 1600A ratingand upto 65kA upto 3200A rating.- The circuit-breakers must be able to be supplied both from the top and bottom terminalswithout derating their performances and without jeopardizing their functionality.

- The circuit-breakers with Higher Electrical & Mechanical life shall be preferred.

1.4.3 Environmental characteristics

- Operating temperature: -25C...+70C (-13F...158F)- Altitude: operation without derating up to 2000m a.s.l.



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- Suitability for being used in hot humid ambient. To this regard, the circuit-breakers mustundergo a Tropicalization process which makes them suitable for use in a hot-humid ambient,in accordance with the international IEC 60068-2-30 Standards.

1.4.4 Construction characteristics

- All the models should be available in 3 and 4 pole versions both in fixed version andwithdrawable versions- The circuit-breaker structure must be made of steel sheet.- In order to ensure maximum operator safety it is necessary to have total segregationbetween the power circuit and control circuit, thus making double insulation necessary.- Total segregation between the phases should be guaranteed for safety reasons.- Key locks or padlock devices should be provided in order to control enabling of opening andclosing operations and/or racking in and out.(wherever specified)- The main contacts should be separate from the arc-breaking contacts.- It should be easily possible to inspect the arcing chamber and the wear of the main contactsof the air circuit-breaker in its racked-out position, by removing the arcing chambers.- All the circuit-breakers in the range should have the same depth and height with the aim ofstandardizing the support structures of the switchboards and the switchboards themselves asmuch as possible.- On the front, the circuit-breakers must indicate the exact position of the main contacts andthe condition of springs charged/discharged by means of certain and reliable signals.- Tripped on fault flag/popup shall be there along with separate reset button on the front otherthan OFF button.- Potential free trip signaling contact and remote electrical reset arrangement are must for allEDO type ACBs.- The operating mechanism should be of the stored energy type, operated using pre-chargedsprings and fitted with an anti-pumping device. The springs are charged manually byoperating the front lever or using a motor operator.- The entire range of air circuit-breakers should be equipped with microprocessor-based overcurrent protection releases and the releases should be provided with rating plug.

Particular details for withdrawable versions

- There must be three positions of the moving part in relation to the fixed part:

- Connected- test (main contacts isolated, auxiliary contacts connected)- isolated



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- The circuit-breakers in the withdrawable version must be fitted with anti-racking-in locks toprevent a moving part with a different nominal current being racked-into a fixed part.- In the case of a withdrawable version, the presence of a device will prevent racking out orracking in with the circuit-breaker closed.- The withdrawable version circuit-breaker must allow racking out and racking in of the circuit-breaker into its fixed part with the switchboard door closed.- Insulating shutters must be provided on the main input and output circuits so that theenergized parts are suitably segregated with the circuit-breaker withdrawn of under test. Whenin the closed position, these shutters can be closed with a padlock.

1.4.5 Accessories

The following accessories must be common to the whole range.- Shunt opening/closing release- Control/Monitoring Test Unit, allows continuity of shunt opening release to be checked- Under voltage release- Time delay device for under voltage release, used for allowing delayed trip of the releasewith adjustable preset times- Geared motor for automatic charging of closing springs- Mechanical and electrical signaling of over current trip units tripped- Auxiliary contacts which enable the state of the circuit breaker to be signaled- Current transformer for the neutral conductor outside the circuit-breaker.- Interlocks between circuit breakers, for interlocking two or three circuit breakers both inhorizontal and vertical position using flexible cables

1.4.6 Protection release functions

- The trip unit should not require an external power supply, being self powered using thecurrent transformers installed on the circuit-breaker.- Release must be of self-diagnostic type which can sense wrong connections at CT, trip coiland rating plugs.- The releases should have integrated LED fault indication for each type of protection i.e. forL, S, I & G.- The releases should allow: inverse long time-delay trip overload protection (L) andinstantaneous short-circuit protection (I), while in addition (wherever specified) the releaseshould have:- short-circuit protection with adjustable delay (S)- earth fault protection with adjustable delay (G)

Main Protection functions & Setting Values



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Function TripThreshold Trip time

L - Overload Protection 0.4 to 1 x In 3s.18s

S Selective short-circuit Protection 1 to 10 x In 0.05s0.5s

I Instantaneous short-circuit protection 1.5.12 x In Instantaneous

G Earth fault protection 0.21 x In 0.1s0.8s

N Neutral Protection 50 - 200 %

All the Protection functions except the one for protection against overload must be excludable.

1.5 MOULDED CASE CIRCUIT BREAKER (MCCB)

MCCB shall be Current Limiting and comprise of Quick Make - break switching mechanism,

preferably Double Break Contact system, arc extinguishing device and the tripping unit shall

be contained in a compact, high strength, heat resistant, flame retardant, insulating moulded

case with high withstand capability against thermal and mechanical stresses. All MCCBs shall

be capable of defined Variable overload adjustment. All shall be provided with electronic tripunit / releases.

The trip command shall override all other commands. MCCB shall employ maintenance free

double break contact system to minimise the let thru energies and capable of achieving

discrimination upto full short circuit capacity of downstream MCCB. The manufacturer shall

check and provide suitable switchgear to achieve total discrimination.

)))) BREAKING CAPACITY:

Short time with-standing capacities & breaking capacities for different ratings ofMCCBs shall be as specified in the SLD or as per the table below if notspecified in the SLD.

o Upto and including 250A 25kA Ics at 415V

o 251A to 630A 35kA Ics at 415V



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o

> 631A 50kA Ics at 415V

Preferably (Ics) shall be equal to (Icu) or all breaking capacities shall beconsidered for (Ics).

Fixing or removal of accessories should not affect the above breaking capacity.It should be possible to remove and replace all the accessories at site from thepoint of servicing and maintenance.

)))) RELEASES:

Unless otherwise specified all MCCBs up to and including 250A shall be

provided with Thermal Magnetic releases & MCCBs of rating greater than 315A shallbe provided with Microprocessor based releases.

All MCCBs with Thermal magnetic releases shall be provided with adjustableoverload & fixed short circuit releases.

Thermo magnetic releases shall be fitted with protection threshold againstoverload and with protection threshold against short-circuit.

All MCCBs with Microprocessor based releases shall be provided withadjustable overload & short circuit releases.

The over current releases must be self-supplied. They must be unaffected by electromagnetic interference in compliance with

the EMC directive on the matter. Wherever earth fault module is required it shall be inbuilt with other releases,i.e. separate module for E/F is not preferred.

The MCCBs shall be provided with rotary handle operating mechanism. The handle positionshall give positive indication of ON, OFF or Tripped thus qualifying to Disconnection as perthe IS/IEC indicating the true position of all the contacts. In case of 4 pole MCCB the neutralshall be defined and capable of offering protection.

The MCCBs shall be provided with extended spreader terminals to provide proper terminationto use with Aluminium Bus Bars.

1.6.1 MOTOR PROTECTION CIRCUIT BREAKER (MPCB)

Motor circuit breakers shall conform to the general recommendations of standard IEC 947 -1,2and 4 (VDE 660, 0113 NF EN 60 947-1-2-4, BS 4752) and to standards UL 508 and CSAC22-2 N14.



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The devices shall be in utilization category A, conforming to IEC 947-2 and AC3 conforming toIEC 947-4.MPCB shall have a rated operational and insulation voltage of 690V AC (50 Hz) and MPCBshall be suitable for isolation conforming to standard IEC 60947-2 and shall have a ratedimpulse withstand voltage (Uimp) of 6 kV. The motor circuit breakers shall be designed to bemounted vertically or horizontally without derating. Power supply shall be from the top or fromthe bottom.In order to ensure maximum safety, the contacts shall be isolated from other functions suchas the operating mechanism, casing, releases, auxiliaries, etc, by high performancethermoplastic chambers. The operating mechanism of the motor circuit breakers must havesnap action opening and closing with free tripping of the control devices.All the poles shall close, open, and trip simultaneously. The motor circuit breakers shallaccept a padlocking device in the isolated position.The motor circuit breakers shall be equipped with a PUSH TO TRIP device on the frontenabling the correct operation of the mechanism and poles opening to be checked.The auxiliary contacts shall be front or side mounting, and both arrangements shall bepossible.The front-mounting attachments shall not change the breaker surface area.Depending on its mounting direction the single pole contact block could be NO or NC.All theelectrical auxiliaries and accessories shall be equipped with terminal blocks and shall be plug-in type.The motor circuit breakers shall have a combination with the downstream contactor enablingthe provision of a perfectly co-ordinated motor-starter. This combination shall enable type 1 ortype 2 co-ordination of the protective devices conforming to IEC 60947-4-1.Type 2 co-ordination shall be guaranteed by tables tested and certified by an official laboratory: LOVAG(or other official laboratory).The motor circuit breakers, depending on the type, could be equipped with a door-mountedoperator which shall allow the device setting. The motor circuit breakers shall be equippedwith releases comprising a thermal element assuring overload protection and a magneticelement for short-circuit protection. In order to ensure safety and avoid unwanted tripping, themagnetic trip threshold (fixed) shall be factory set to an average value of 12 Ir.All the elements of the motor circuit breakers shall be designated to enable operation at anambient temperature of 50C without derating.The thermal trips shall be adjustable on the thefront by a rotary selector.The adjustment of the protection shall be simultaneous for allpoles.Phase unbalance and phase loss detection shall be available.Temperaturecompensation (-20C to +60C)

1.7 Switch Fuse Units, Disconnecting Switches and FusesAll switches shall be load double break, heavy duty air break type provided with quick makebreak manual operating mechanism. The operating handle shall be mounted in the door of thecompartment having the switch.Switches shall be designed to carry the rated current continuously without overheating.



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Barriers shall be provided to prevent interphase arcing and live terminals shall be shrouded toavoid accidental contact.The switches shall be rated for AC23A duty.Auxiliary switches shall be provided with a minimum of two NO contacts, rated for 5A, 230VAC.Fuses shall be non-deteriorating HRC cartridge link type. Diaze fuses are not acceptable.The fuses shall be provided with operation indicator which shall be visible without removal offuses from service.Fuses shall be pressure fitted type and shall preferably have rims on the contact blades toensure good line contact.It shall be possible to handle fuses during off load conditions with full voltage available on theterminals. Wherever required, fuse pullers shallbe provided.

1.8 Contactors

The contactors shall be air break type, equipped with three main contacts and minimum 2 NO+ 2 NC auxiliary contacts. The main contacts of a particular contactor shall haveAC3 ratings for general AC motor circuits,AC4 for RDOL feeders andAC5a for AC lighting circuits as per IEC 60947.The auxiliary contacts shall be rated for minimum 5 Amps at 230 V AC and 110 V DC.Unless specified otherwise, the coil of the contactor shall be suitable for operation on 110VAC supply and shall work satisfactorily between +10% and -15% of the rated voltage.The contactor drop-off voltage shall be between 30% to 65% of the rated coil voltage.Auxiliary contactors shall generally be used for interlocking and multiplying contacts. Auxiliarycontacts shall be capable of carrying the maximum estimated current, but not less than 5A at230V AC.

1.9 Over Load Relays

Overload relays will be of bi-metallic thermal overload type or electronic type as specified inthe drawings.Bi-metallic Over Load Relay, three element type directly mounted, front adjustable, ambienttemperature compensated bimetallic devices of suitable range to match with the rating /Output of the motors connected to the related starter and complete with hand resetting device.The relays shall be provided with minimum 1 NO + 1 NC contacts with a rating of 5 Amps at240 V, 1PH, 50 Hz AC and 1.3 Amps at 110 V DC (Inductive load). The bi-metallic relays shallhave double slide mechanism for single phase failure detection even at partial load conditions.Microprocessor based earth fault relay shall be additionally provided with CBCT whereverspecified. Microprocessor type overload relays shall have motor stalling, single phasing,locked rotor, earth fault and overload protections, as a minimum and shall be suitable for theambient that will be prevalent in the switchboard. Necessary core balancing current



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transformers, as required for earth fault protection shall be arranged. The relay shall have in-built time delay setting facility for tripping. The relays shall preferably be of CT operated type.Class 20 relays shall be considered wherever the starting time is expected to be very high.

1.10 INDICATING PANEL

All meters and indicating instruments shall be in accordance with relevant Indian Standards.

The meters shall be flush mounted type. Indicating lamps shall be of LED type, and shall be

backed up with MCB / MPCB.

1.11WIRING

In wiring the single phase loads of a power distribution panel it shall be insured that total load

of various panel and/or consuming devices is divided evenly between the phases and number

of ways.

1.12 ANTI-CONDENSATION SPACE HEATERS

1 No. 100 W, 240 volts, single phase, 50 Hz AC Anti Condensation space heaters controlled

by thermostat and protected by 6 amps SP MCBs/MPCB shall be provided in each vertical

section of Main LT Panel synchronizing panel Power Distribution Panel, MCCs and 1 No. 60

watt Anti Condensation space heater shall be provided in each cable alley of main distribution

boards and sub distribution boards. Supply and control equipment for the above shall be

provided by the vendors.

1.13 EARTHINGEarthing shall be provided as per IS:3043-1987.

1.14 PAINTINGAll sheet steel work shall undergo a process of degreasing, pickling in acid, cold rinsing,phosphating, passivaiting (seven tank processing) and then painted with electrostatic paint(Powder coating). The shade of colour of panel inside/outside shall be confirming to IS CodeNo.5.



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1.15 LABELSEngraved PVC labels shall be provided on all incoming and outgoing feeder. Circuit diagramshowing the arrangements of the circuit inside the distribution panels shall be pasted on insideof the panel door and covered with transparent plastic sheet.

1.16 METERSi. All voltmeters and indicating lamps shall be through MCBs.ii. Meters and indicating instruments shall be flush type.iii. All CTs connection for meters shall be through Test Terminal Block (TTB).

1.17 CURRENT TRANSFORMERS

Current transformers shall be provided for Distribution panels carrying current in excess of 60amps. All phase shall be provided with current transformers of suitable VA burden with 5amps secondaries for operation of associated metering.The CTs shall confirm to relevant Indian Standards. The design and construction shall be drytype, epoxy resin cast robust to withstand thermal and dynamic stresses during short circuits.Secondary terminals of CTs shall be brought out suitable to a terminal block which shall beeasily accessible for testing and terminal connections. The protection CTs shall be ofaccuracy class 5P10 and measurement CTs shall be of accuracy class I.

1.18 PUSH BUTTONS, SELECTOR SWITCHES AND PILOT LAMPS

The push buttons shall be of shrouded type with actuator provided with escutcheon platesmarked with its function on it.Control switches shall be of the heavy duty rotary type with name plates clearly marked toshow the operation. They shall be semi-flushed mounting with only the front plate andoperating handle projecting.Circuit breaker control switches shall be of the spring return to neutral type, while local /remote selector switches and instrument selector switches shall be of the stay-put type.The indicating lamps shall be of cluster LED type of low watt consumption. They shall beprovided with series resistors.

1.19 LOW VOLTAGE 1.1 KV GRADE XLPE / PVC CABLES

1.19.1GENERALThe LV cables shall be supplied, inspected, laid, tested and commissioned in accordance withdrawings, Specifications, relevant Standard Specifications and cable manufacturer'sinstruction.

1.19.2MATERIAL



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The LV cables shall be cross linked polyethylene (XLPE) insulated PVC sheathed of 1100volts grade as asked for in the schedule of quantities. Cables upto 16 sq.mm shall be withcopper conductor and 25 sq.mm and above shall be with aluminium conductor.

1.19.3TECHNICAL REQUIREMENTS :

All XLPE Aluminium/Copper Power cables shall be 1100 Volts grade, multi core constructedas per IS : 7098 Part-I of 1988 as follows :a) Stranded Aluminium /Copper conductor in case of 10 sq.mm. and above and solidconductor in case of 10 sq.mm. and below.b) Cores laid upc) The inner sheath should be bonded over with thermo-plastic material for protection againstmechanical and electrical damage.d) Armoring should be provided over the inner sheath to guard against mechanical damage.Armouring should be Galvanised steel wires or galvanised steel strips. (In single core cablesused in A.C. system armouring should be non-magnetic hard aluminium Wires/Strips. Roundsteel wires should be used where diameter over the inner sheath does not exceed 13 mm;above 13 mm flat steel armour should be used. Round wire of different sizes should beprovided against specific request.)e) The outer sheath should be specially formulated heat resistant black PVC compoundconforming to the requirement of type ST2 of IS : 5831-1984 extruded to form the outersheath.Conductor shall be of electrolytic Aluminium/Copper conforming to IS : 8130 and are compactcircular or compact shaped.Insulation shall be of XLPE type as per latest IS general purpose insulation for maximumrated conductor temperature 70 degree centigrade.In Inner sheath laid up cores shall be bonded over with thermoplastic material for protectionagainst mechanical and electrical damage.Insulation, inner sheath and outer sheath shall be applied by extrusion and lapping up processonly.Armouring shall be of galvanised steel wire/flat.Repaired cables shall not be used.Current ratings of the cables shall be as per IS : 3961.The XLPE insulated cables shall conform to latest revision IS read along with thisspecifications. The Conductor shall be stranded Aluminium/Copper circular/ sector shapedand compacted. In multi core cables the core shall be identified by red, yellow, blue and blackcoloring of insulation.The XLPE insulated 1100 Volts grade power cables shall conform to latest IS and shall besuitable for a steady conductor temperature of 70 degree centigrade. The conductor shall bestranded Aluminium/Copper as called for in the Schedule of quantities. The outer sheath shallbe as per the requirement of type ST-2 of IS:5831 of 1984.The cables shall be suitable for laying in racks, ducts, trenches, conduits and undergroundburied installation with uncontrolled back fill and chances of flooding by water.



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Progressive automatic in line sequential marking of the length of cables in meters at everyone meter shall be provided on the outer sheath of all cables.Cables shall be supplied in non returnable wooden drums as per IS : 10418.Both ends of the cables shall be properly sealed with PVC/Rubber caps so as to eliminateingress of water during transportation, storage and erection.

1.19.4 INSPECTION

All cables shall be inspected by the contractor upon receipt at site and checked for anydamage during transit.

1.19.5JOINTS IN CABLESThe Contractor shall take care to see that all the cables received at site are apportioned tovarious locations in such a manner as to ensure maximum utilization and avoidance of cable

jointing. This apportioning shall be got approved by the Owners site representative before thecables are cut to lengths. Where joints are unavoidable heat shrinkable type joints shall bemade. The location of such joints shall be got approved from the Owners site representativeand shall be identified through a marker.

1.19.6JOINTING BOXES FOR CABLESCable joint boxes shall be installed with heat shrinkable sleeve and of appropriate size,suitable for XLPE armoured cables of particular voltage rating.

1.19.7JOINTING OF CABLESAll cable joints shall be made in suitable, approved cable joint boxes and the filling in ofcompound shall be done in accordance with manufactures' instructions and in an approvedmanner. All straight joints shall be done in epoxy mould boxes with epoxy resin.

All cables shall be joined colour to colour and tested for continuity and insulation resistancebefore jointing commence. The seals of cables must not be removed until preparations for

jointing are completed. Joints shall be finished on the same day as commenced and sufficientprotection from the weather shall be arranged. The conductors shall be efficiently insulatedwith high voltage insulating tape and by using of spreaders of approved size and pattern. The

joints shall be completely topped up with epoxy compound so as to ensure that the box isproperly filled.

1.19.8CABLE TERMINATIONSCable termination shall be done in cable terminal box using crimping sockets and proper sizeof glands of double compression type with earthing facility.



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1.19.9BONDING OF CABLESWhere a cable enters any piece of apparatus, it shall be connected to the casing by means ofan approved type of armour clamp and gland. The clamps must grip the armouring firmly tothe gland or casing, so that no undue stress is passed on to the cable conductors.

1.19.10LAYING OF CABLES ON CABLE TRAYSCables shall be laid by skilled and experienced workmen using adequate rollers to minimizestretching of the cable. The cable drums shall be placed on jacks before unwinding the cable.Great care shall be exercised in laying cables to avoid forming kinks. The relative position ofthe cables, laid on the cable tray shall be preserved and the cables shall not cross each other.At all changes in direction in horizontal and vertical planes, the cable shall be bent smoothwith a radius as recommended by the manufacturers. All cables shall be laid with minimumone diameter gap and shall be clamped at every metre to the cable tray and shall be taggedfor identification with aluminum tag and clamped properly. Tags shall be provided at both endsand all changes in directions both sides of wall and floor crossings. All cable shall be identifiedby embossing on the tag the size of the cable, place of origin and termination.All cables passing through holes in floor or walls shall be sealed with fire retardant Sealantand shall be painted with fire retardant paint upto one meter on all joints, terminations andboth sides of the wall crossings by VIPER CABLE RETARD.

1.19.11 LAYING OF CABLES IN GROUNDThe minimum width of trench for laying single cable shall be minimum 350 mm. Where morethan one cable is to be laid in horizontal formation, the width of the trench shall be workout byproviding 200 mm gap between the cables, except where otherwise specified. There shall beclearance of 150 mm between the end cable and the side wall of the trench. The minimumdept of the cable trench shall not be less than 750 mm for single layer of cables. When thecables are laid in more than one tier the depth of the trench shall be increased by 300 mm foreach additional tier.

Excavation of trenches : The trenches shall be excavated in reasonably straight lines.Wherever there is a change in direction, suitable curvature shall be provided. Where gradientsand changes in depth are unavoidable, these shall be gradual. The excavated soil shall bestacked firmly by the side of the trench such that it may not fall back into the trench. Thebottom of the trench shall be level and free from stone, brick bats etc. The trench shall then beprovided with a layer of clean, dry sand cushion of not less than 100 mm in depth. Prior tolaying of cables, the cores shall be tested for continuity and insulation resistance. The cabledrum shall be properly mounted on jacks, at a suitable location, making sure that the spindle,

jack etc. are strong enough to carry the weight of the drum and the spindle is horizontal. Cableshall be pulled over rollers in the trench steadily and uniformly without jerks and strains. Theentire drum length shall be laid in one stretch. However, where this is not possible theremainder of the cable shall be removed by `Flaking i.e. by making one long loop in thereverse direction. After the cable has been uncoiled and laid into the trench over the rollers,the cable shall be lifted off the rollers beginning from one end by helpers standing about 10meters apart and laid in a reasonably straight line. Cable laid in trenches in a single tier



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formation shall have a cover of clean, dry sand of not less than 150 mm. above the basecushion of sand before the protective cover is laid. In the case of vertical multi-tier formationafter the first cable has been laid, a sand cushion of 300 mm shall be provided over the initialbed before the second tier is laid. Finally the cables shall be protected by second class bricksbefore back filling the trench.

Back Filling : The trenches shall be back filled with excavated earth free from stones or othersharp edged debris and shall be rammed and watered, if necessary, in successive layers notexceeding 300 mm. Unless otherwise specified, a crown of earth not less than 50 mm in thecentre and tapering towards the sides of the trench shall be left to allow for subsidence.

1.19.12CABLES INSIDE THE PLANT

Cables inside buildings shall be laid on the cable trays. All cables passing through walls shallrun through GI Pipes of adequate diameter 50 mm apart maintaining the relative position overthe entire length.

1.19.13ROUTE MARKERRoute marker shall be provided along straight runs of the cables not exceeding 100 metersalso for change in the direction of the cable route and underground joints.Route marker shall be of cast iron painted with aluminum paint. The size of marker shall be100 mm dia with Cable and voltage grade inscribed on it.

1.19.14CABLE TRAYSCable Trays shall be Galvanized and factory fabricated out of MS channels, angle iron, tee,

bends, sections, flats and perforated sheet for different loads and number and size of cablesas given below :

Cable trays shall be galvanized as per Specification given elsewhere.a. 1500 mm wideRunners 25 x 100 x 25 x 3 mmRungs 20 x 40 x 20 x 3 mm 250 mm C/CSuspenders 2 Nos. 40 x 40 x 5 mm GI angle 1500 mm C/C

b. 1200 mm wideRunners 25 x 100 x 25 x 3 mmRungs 20 x 40 x 20 x 3 mm 250 mm C/C

Suspenders 2 Nos. 40 x 40 x 5 mm GI angle 1500 mm C/C

c. 1000 mm wideRunners 25 x 100 x 25 x 3 mmRungs 20 x 40 x 20 x 3 mm 250 mm C/CSuspenders 2 Nos. 40 x 40 x 5 mm GI angle 1500 mm C/C



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d. 750 mm wideRunners 20 x 75 x 20 x 2.5 mmRungs 20 x 30 x 20 x 2.5 mm 250 mm C/CSuspenders 2 Nos. 32 x 32 x 5 mm GI angle 1800 mm C/C

e. Supply and fixing of perforated type cable trays of the following sizes of pre-galvanized iron.i. 600 x 40 x 40 x 2 mm thicki. 450 x 40 x 40 x 2 mm thicki. 300 x 40 x 40 x 2 mm thickii. 150 x 40 x 40 x 2 mm thick

Suitable length of 8 mm dia GI rod suspenders at 2000 mm intervals shall be included in theitem for perforated type cable tray.

1.20SPECIFICATION FOR HOT DIP GALVANIZING PROCESS FOR MILD STEEL USEDFOR EARTHING, CABLE TRAYS OR JUNCTION BOXES FOR ELECTRICALINSTALLATION.

1.20.1 Quality of ZincZinc to be used shall conform to minimum Zn 98 grade as per requirement of IS:209-1992.

1.20.2 Coating RequirementMinimum weight of zinc coating for mild steel flats with thickness upto 6 mm in accordancewith IS:6745-1972 shall be 400 g/sqm.The weight of coating expressed in grams per square metre shall be calculated by dividing thetotal weight of Zinc by total area (both sides) of the coated surface.The Zinc coating shall be uniform, smooth and free from imperfections as flux, ash and drossinclusions, bare patches black spots, pimples, lumpiness, runs, rust stains bulky whitedeposits, blisters.Mild steel flats / wires shall undergo a process of degreasing pickling in acid, cold rinsing andthen galvanizing.

1.21TESTING OF CABLES

Cables shall be tested at works for the following tests before being dispatched to site by theproject team.

a) Insulation Resistance Test.b) Continuity resistance test.c) Sheathing continuity test.d) Earth test.(in armoured cables)



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e) Hi Pot Test.

Test shall also be conducted at site for insulation between phases and between phase andearth for each length of cable, before and after jointing.

On completion of cable laying work, the following tests shall be conducted in the presence ofthe Owners site representative.

a) Insulation Resistance Test( Sectional and overall)b) Continuity resistance test.c) Sheathing continuity test.d) Earth test.

All tests shall be carried out in accordance with relevant Standard Code of Practice andElectricity Rules. The Contractor shall provide necessary instruments, equipment and labourfor conducting the above tests and shall bear all expenses in connection with such tests. Alltests shall be carried out in the presence of the Owners site representative.


specification of lt

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