Electrical Specifications

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Low Voltage Panel (LV Panel)

General

The contractor shall supply, install and commission the L.V Panel(s) as shown on the drawings

and as herein specified.

The components used in the L.V Panel shall comply to the specification described under

Components for Panel Boards in this section.

The enclosures, circuit breakers and other major devices should be from one reputed and

approved manufacturer.

The manufacturer and local assembler of the switchboards should have ISO9001 certification.

The L.V Panel shall be assembled by the Franchised Panel Builders of the approved

manufacturer. The franchised panel builder shall have a minimum of 5years experience under the

franchisee agreement.

Type Test Certificate shall be submitted for the L.V Panel from the manufacturer and also from

the franchised panel builder.

LV panel shall be approved by the local electricity authority.

All the test equipments at the local assembler factory shall be calibrated at reputed laboratory in

regular time interval. In particular the crimping tools and the torque wrenches used at local

assembler factory should be calibrated and certified. Certificate copies shall be submitted for

verification.

The LV panel shall be factory tested by the manufacturer at their works prior to delivery to the

site. Factory Test Certificates shall be provided along with the delivery of the panel when

dispatched to the site.

The panel builder shall provide a installation, operation and maintenance procedure for the panel

and the contractor shall strictly follow such procedure.

The panel builder shall be present at site for testing and commissioning of the LV panel at site

after installation.

Approval shall be obtained from the COMPANY for the constructional details, power & control

schematic diagram and installation details prior to manufacturing.

LV Panel Assembly

LV Panel shall comprise of free standing enclosure, bus bar system, switch gear such as

ACB/MCCB, metering equipments, all necessary current transformers and the like as required.

Panel shall be assembled in a systematic manner such as Transformer Incomer section, Generator

Incomer section (if applicable), Bus coupler section (if applicable), Incomer Metering / Indication

section and Outgoing section.

The LV Panel shall be designed to have a continuous current rating and minimum short circuit

rating as specified in the drawings. It shall comply with IEC439-1 and BS 4586 Part 1 standards

for fully type tested assemblies.

Unless otherwise specified the panels shall be designed to accept bottom entry of cables and shall

be of rear access type. The rear access shall only be provided for access for termination of cables,

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all other equipments shall be accessible / operable from the front of panel. Where front access

type is specified, the panel shall be designed completely for front access only.

Each panel section shall be provided with thermostatically controlled panel heater.

Labelling of the panels, circuit / feeder description, components etc. shall be done in a approved

and systematic manner. All such labels shall be either of anodized aluminum or special PVC

material, front engraved with black text on white back ground.

Each section shall be typically as described below:

Incomer section (Transformer Incoming)

The Transformer Incomer panel shall be a 3compartment enclosure with Top & Bottom

compartment dedicated for metering / controls and the Middle compartment shall be dedicated for

the circuit breaker. It shall comprise of but not limited to the following:

Bottom Compartment

Incomer supply cables

1no. Voltmeter to measure phase to phase, phase to neutral voltages with 7Pos. selector

switch wired to the line side of the circuit breaker.

3nos. Phase Indication lamps (R, Y, B) wired to the line side of the circuit breaker.

3nos. Control fuses for voltmeter.

Any control component for Incoming circuit breaker.

Middle Compartment

Main Incoming circuit breakers with rating and type as indicated on the drawing.

Top Compartment

3nos. Ammeter to measure the load current on each phase.

1no. Voltmeter to measure phase to phase and phase to neutral voltages with 7Pos. selector

switch wired to the load side of the circuit breaker.

3nos. Phase indication lamps (R, Y, B) wired to the load side of the circuit breaker.

1no. Power factor meter (If required as per local authority requirement).

1no. KWh energy meter (If location of KWh is approved by local authority).

Incomer section (Generator Incoming) – (If applicable)

The Generator Incomer panel shall be a 3compartment enclosure with Top & Bottom

compartment dedicated for metering / controls and the Middle compartment shall be dedicated for

the circuit breaker. It shall comprise of but not limited to the following:

Bottom Compartment

Incomer supply cables.

1no. Voltmeter to measure phase to phase and phase to neutral voltages with 7Pos. selector

switch wired to the line side of the circuit breaker.

3nos. Phase Indication lamps (R, Y, B) wired to the line side of the circuit breaker.

3nos. Control fuses for voltmeter.

Any control component for Incoming circuit breaker.

Middle Compartment

Main Incoming circuit breakers with rating and type as indicated in the drawing.

Top Compartment

3nos. Ammeter to measure the load current on each phase.

1no. Voltmeter to measure phase to phase, phase to neutral voltages with 7Pos. selector

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3nos. Phase indication lamps (R, Y, B) wired to the load side of the circuit breaker.

1no. Frequency meter.

1no. Kilo watt meter (If indicated on the drawing).

Bus Tie section – (If applicable)

The Bus Tie / Bus Coupler Panel shall be a 3compartment enclosure to match with the incomer

panels. The Top & Bottom compartment can be used for accommodating the common controls of

the incoming and the bus tie circuit breakers. The Middle compartment shall be dedicated for the

circuit breaker. It shall comprise of but not limited to the following:

Bottom Compartment

Any control component for bus coupler circuit breaker.

Middle Compartment

Bus coupler circuit breakers with rating and type as indicated in the drawing.

Top Compartment

Any control component common for both bus coupler and incoming circuit breakers.

Note: When ACB’s are used as incoming or bus coupler circuit breakers, the front face of the

ACB shall be accessible for operation from the front without opening the front door. When

MCCB’s are used as incoming or bus coupler circuit breakers an extended operating handle shall

be provided at the front face of the panel front door for operation. All such door handles shall be

door interlocked wherever required.

Outgoing section(s)

The outgoing section(s) enclosure shall accommodate the outgoing circuit breakers which shall be

arranged in a systematic and symmetrical manner. It shall comprise of but not limited to the

following:

In case of Form – 2 Construction

Each panel shall have its own common door at front and each panel shall accommodate the

following:

a. Circuit breakers with rating and type as specified in the drawings.

b. Any other controls, which may be part of the outgoing circuit breakers.

Note:

All circuit breakers / operating knobs shall be accessible after opening the panel door, which

shall be lockable.

All circuit breakers shall be installed behind a metallic front plate in such way that only the

breaker operating knobs (in case of MCCBs) and front face of circuit breaker (in case of

ACBs) are accessible for operation after opening of front door.

Removal of the front plate shall give access to the circuit breaker for rating adjustments etc.

Removal of the front plates shall not give direct access to the bus bars. All interconnection

bus bars shall be accessible after removal of another poly carbonate shroud.

Maximum 2nos. air circuit breakers shall be installed in one enclosure, provided that

sufficient space for cable termination is provided.

Maximum 2nos. MCCBs, if rated more 800Amps shall be installed in one enclosure,

provided that sufficient space for cable termination is provided.

Enclosure Construction

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The LV Panel shall be factory-built type in compliance with the IEC 439-1 and BS5486 to

construction of type-tested assemblies (TTA). They shall also comply with IEC 529 as regards

the degree of protection of the enclosures.

The protection index shall be IP54 as defined defined in accordance with the IEC 529 standard.

The rated operational voltage of the LV Panel shall be up to 690V AC.

The rated insulation voltage of the LV Panel shall be up to 1000V AC / 750V DC.

The board shall consist of a number of enclosures of equal height and depth mounted side by side

to form a composite board of uniform assembly having access to the power cables on the front /

rear side. The depth shall be same throughout the panel except for the incoming / bus tie section,

where the depth may be more to enable free cable access and termination.

All enclosures shall be made of electro galvanized steel sheet plate having a minimum thickness

of 1.5mm.The enclosure composition shall be based on a supporting frame consisting of cross

members, vertical members and panels fastened to one another by means of the bolts and rivets.

A single piece base shall allow the anchoring of the unit to the floor. The resulting assembly shall

be a rigid self supporting structure which shall be indeformable and unaffected by shocks. The

structure shall be closed - on the top through removable bolted plates giving access to the main

bus bars, at the front through hinged doors, at the rear by hinged door and on opposite sides of the

assembly by means of removable bolted plates. The lower part shall be closed by means of bolted

plates that can be removed whenever the assembly of cable glands is required. Partitions between

individual compartments shall be provided(where ever required). The whole assembly shall

withstand the maximum force exerted by its peak rated short circuit current without deformation.

Each door shall be equipped with integral locks. Keys shall be common for all such locks.

All doors, bolt on covers, mounting plates and partitions shall be effectively connected to the

earth bar by means of flexible wire.

All door hinges shall be of concealed type. It shall be possible to remove the door easily when

required.

Panel shall be of front access type for the purpose of access all the components, and of rear access

type for the purpose of cable terminations where ever required.

Adequate care shall be taken in design of panels considering the connection space for the external

cables. The panels shall include sufficient cable supports for routing the cables inside the

enclosure. Wherever single core cables enter, the gland plate shall be either of aluminium or brass

plates.

The enclosure construction shall integrate a natural ventilation system aimed at regulating the

internal temperature based on the actual capacities of components.

The structure and partitions shall be protected by a thermo polymerised polyester epoxy powder

coating to an approved colour after pre treatment of the sheet metal.

Form of construction shall comply to Form –2 / 4 as per IEC 439-1 standards and as specified in

the drawings.

The enclosure shall be suitable for future extensions without any modifications (after installation

at site).

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A quality assurance program shall submitted for approval for prior to the assembly /

manufacturing of the enclosures.

Busbar System

Busbar system shall consist of one or more tinned copper conductors fastened to the structure by

means of appropriate insulating supports.

The bus bars system shall be completely shrouded with special poly carbonate sheets or with

metallic shrouds as applicable. Use of bakelite sheets will not be permitted.

All the bus bars used in the panel shall be of high grade electrolytic tinned copper of 99.9%

conductivity. The bus bars shall be colour sleeved through out the length for phase identification .

The size of the neutral bus bar shall be same as the phase busbar. The neutral bus bars shall be

colour sleeved through out the length for phase identification.

The size of the earth bus bar shall be half the size of the earth busbar. The earth bus bar shall be

identified with green / yellow-green tapes at intermediate intervals.

The dimensioning of the horizontal and vertical bus bar system shall be as per the rated current,

the short circuit current, the maximum admissible temperature at permanent operation < 110deg.

C and the ambient temperature around the bus bars. Bus bar sizing shall also comply to the local

authority regulations.

The main or horizontal bus bar system shall be located in the upper section of the assembly and

its function is the distribution of current to the individual section forming the assembly. All the

phase, neutral and earth busbars shall run throughout the length of the panel.

The vertical bus bar system shall be designed same as the horizontal bus bar system. If the bus

bar sizes of the vertical droppers are reduced then it shall be designed to carry 1.5times the total

current of the feeders connected to them.

The connections to the individual circuit breakers shall be done by rigid bus bars. They shall be

suitably sized to suit the breaker current rating. It shall be possible to replace the breakers with

different ratings within its frame size without changing the connection bus bars.

Calculations shall be submitted to prove the adequacy of the size of the bus bars for the rated

current.

All the main horizontal and vertical bus bars shall be located in its own separate compartment.

The bus bar compartment shall be provided with removable metallic front plates to prevent

accidental access to bus bars. Each metallic shrouds shall be provided with engraved warning

labels indicating ‘ Danger – 415V Live Bus Inside – Isolate Main Supply Before Opening This

Cover’ at the front face. All such warning labels shall be riveted to the shroud plates.

The line side of the incoming circuit breaker and its bus bar shall be shrouded separately with

removable metallic front plates to prevent accidental access to bus bars. Such shrouds shall be

provided with engraved warning labels indicating ‘Danger – 415V Live Bus Inside – Isolate

Supply Else Where Before Opening This Cover’ at the front face. All such warning labels shall

be riveted to the shroud plates.

All warning labels shall be of anodised aluminium or special pvc material, front engraved type

with white / black text on red / yellow back ground.

The main three phase, neutral and earth bus bars shall extend throughout the entire length of

panel. They shall be with predrilled holes at the ends for future extensions without any

modifications (after installation at site).

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When future space provision is indicated on the drawings, The space shall be complete in all

respects including fixing arrangement, bus bar connections, shrouds etc,(except the breaker).

The bus bars shall be suitably extended, drilled and provided with required bolts and nuts to

connect the external cables to the switchgear.

All bolts, nuts used for bus bar connection shall be of suitable size and grade.

Adequate care shall be taken in maintaining the clearances and creepage distances through out the

panels. All clearances and creepage distances shall be in accordance to IEC439-1 standards.

The complete bus bar design shall be based on ambient temperature of 50° C and shall be

designed to with stand the temperature rise inside the enclosure.

Electrical continuity of the metal parts shall be ensured by a protective conductor consisting

suitably sized tinned electrolytic copper bar. This conductor shall be directly mounted to the

structures and include a horizontal bar with holes drilled to allow the connection of the protective

conductor of the power cables.

Main Distribution Board (MDB)

General

The contractor shall supply, install and commission the Main Distribution Board(s) (MDB) as

shown on the drawings and as herein specified.

The components used in the main distribution board shall comply with the specification described

under Components for Panel Boards in this section.




The MDB shall be assembled by the Franchised Panel Builders of the approved manufacturer.

The franchised panel builder shall have a minimum of 5years experience under the franchisee

agreement.

Type Test Certificate shall be submitted for the MDB from the manufacturer and also from the

franchised panel builder.

MDB shall be approved by the local electricity authority.




verification.

The MDB shall be factory tested by the manufacturer at their works prior to delivery to the site.

Factory Test Certificates shall be provided along with the delivery of the panel when dispatched

to the site.

The panel builder shall provide an installation, operation and maintenance procedure for the panel


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The panel builder shall be present at site for testing and commissioning of the MDB at site after

installation.

Approval shall be obtained from the consultant/engineer for the constructional details, power &

control schematic diagram and installation details prior to manufacturing.

Main Distribution Board Assembly

MDB shall comprise of free standing enclosure, bus bar system, MCCB, metering equipments, all

necessary current transformers and the like as required. Panel shall be assembled in a systematic

manner such as Incomer section and Outgoing section.

MDB shall be designed to have a continuous current rating and minimum short circuit rating as

specified in the drawings. It shall comply with IEC439-1 and BS 4586 Part 1 standards for type

tested assemblies.

MDB shall be designed to accept bottom entry of cables and shall be of front access type.

Each panel section shall be provided with thermostatically controlled panel heater.

Labelling of the panels, circuit / feeder description, components etc. shall be done in an approved


material, front engraved with black text on white background.

Each section shall be typically as described below:

Incomer section

The Mains Incomer panel shall be dedicated for the incoming circuit breaker and its metering

equipments. It shall comprise of but not limited to the following:

a. Main Incoming circuit breakers with rating and type as indicated in the drawing.

b. 1nos. Ammeter to measure the load current on each phase with 4pos. selector switch.

c. 1no. Voltmeter to measure phase to phase, phase to neutral voltages with 7Pos. selector


d. 3nos. Phase indication lamps (R, Y, B) wired to the load side of the circuit breaker.

e. 1no. Power factor meter in mains incomer (If required as per local authority requirement).

f. KWh energy meter in mains incomer (If location of KWh is approved by local authority).

g. 2no. Voltmeter to measure phase to phase, phase to neutral voltages with 7Pos. selector

switch wired to the line side of the circuit breaker of mains and generator incomer (if

applicable).

h. 3nos. Phase indication lamps (R, Y, B) wired to the line side of the circuit breaker of mains

and generator incomer (if applicable).

Note:

An extended operating handle shall be provided at the front face of the panel front door for

operation of the incoming circuit breaker. All such operating handles shall be door

interlocked wherever required.

All circuit breakers shall be installed behind a metallic/ poly carbonate sheet front plate in

such way that only the breaker operating knobs are accessible for operation after opening the

door.


If the incomer rating is more than 630Amps, the incoming circuit breaker shall be located in a

separate cubicle. Otherwise Incoming and outgoing breakers can be one common cubicle,

however they shall be separated from each other by shrouding.

If a generator incoming is connected to the MDB, The generator incomer shall be placed

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adjacent to the mains incoming MCCB. Both the MCCBs shall be electrically and

mechanically interlocked. All the incoming cabling terminations, bus bars etc. shall be fully

shrouded and segregated from each other. The arrangement shall be approved by the local

authority.

Outgoing section(s)

Outgoing section(s) panel(s) shall accommodate the outgoing circuit breakers, which shall be

arranged in a systematic and symmetrical manner. It shall comprise of but not limited to the

following:

Each panel shall have its own common door at front and each panel shall accommodate the

following:

a. Circuit breakers with rating and type as specified in the drawings.

b. Any other controls, which may be part of the outgoing circuit breakers.

Note:

All circuit breakers / operating knobs shall be accessible after opening the panel door.

All circuit breakers shall be installed behind a metallic / polycarbonate sheet front plate in

such way that only the breaker operating knobs are accessible for operation after opening of

front door.


Removal of the front plates shall not give direct access to the main bus bars. The main bus

bar shall be accessible after removal of another polycarbonate shroud.

Enclosure Construction

The MDB shall be factory-built type in compliance with the IEC 439-1 and BS5486 to



The protection index shall be IP54 as defined in accordance with the IEC 529 standard.

The rated operational voltage of the MDB shall be up to 690V AC.

The rated insulation voltage of the MDB shall be up to 1000V AC / 750V DC.

The board shall consist of a number of enclosures of equal height and depth mounted side by side

to form a composite board of uniform and pleasing appearance with access to the power cables on

the front side. The boards shall be suitable for floor mounting / wall mounting as required.

The enclosure shall be of monobloc type with folded and welded construction fabricated out of

1.5mm electro galvanized steel sheet to form a cubicle. Hinged door shall be provided for each

cubicle. Removable gland plate shall be provided at the bottom of the enclosure.The whole

assembly shall withstand the maximum force exerted by its peak rated short circuit current

without deformation.

Each door shall be equipped with integral locks. Keys shall be common for all such locks.

All doors, bolt on covers, mounting plates and partitions shall be effectively connected to the

earth bar by means of flexible wire.

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required.

Panel shall be of front access type for the purpose of access all the components, and also for the

purpose of cable terminations.




plates.



The enclosure shall be protected by a thermo polymerised polyester epoxy powder coating to an

approved colour after pre treatment of the sheet metal.

Form of construction shall comply to Form –2 as per IEC 439-1 standards or as specified in the

drawings.

A quality assurance program shall submitted for approval for prior to the assembly /

manufacturing of the enclosures.

Busbar System

Bus bar system shall consist of one or more tinned copper conductors fastened to the structure by

means of appropriate insulating supports.

The bus bars system shall be completely shrouded with special poly carbonate sheets or with

metallic shrouds as applicable. Use of bakelite sheets will not be permitted.

All the bus bars used in the panel shall be of high grade electrolytic tinned copper of 99.9%

conductivity. The bus bars shall be colour sleeved through out the length for phase identification.

The size of the neutral bus bar shall be same as the phase busbar. The neutral bus bars shall be

colour sleeved through out the length for phase identification.

The size of the earth bus bar shall be half the size of the earth busbar. The earth bus bar shall be

identified with green / yellow-green tapes at intermediate intervals.

The dimensioning of the horizontal and vertical bus bar system shall be as per the rated current,

the short circuit current, the maximum admissible temperature at permanent operation < 110deg.

C and the ambient temperature around the bus bars. Bus bar sizing shall also comply to the local

authority regulations.

The main bus bar system shall be preferably located in the upper section of the assembly and its

function is the distribution of current to the individual section forming the assembly.

The sub bus bar / vertical dropper of main bus bar system shall be designed same as the main bus

bar system. If the bus bar sizes of the sub bus bar / vertical droppers are reduced then it shall be

designed to carry 1.5times the total current of the feeders connected to them.

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different ratings within its frame size without changing the connection bus bars.


current.

All the main horizontal and vertical bus bars shall be segregated from other components.

The main bus bars shall be provided with removable poly carbonate sheet / metallic front plates to

prevent accidental access to bus bars. Each poly carbonate sheet / metallic shrouds shall be

provided with engraved warning labels indicating ‘ Danger – 415V Live Bus Inside – Isolate

Main Supply Before Opening This Cover’ at the front face. All such warning labels shall be

riveted to the shroud plates.

The line side of the incoming circuit breaker and its bus bar shall be shrouded separately with

removable poly carbonate sheet / metallic front plates to prevent accidental access to bus bars.

Such shrouds shall be provided with engraved warning labels indicating ‘Danger – 415V Live

Bus Inside – Isolate Supply Else Where Before Opening This Cover’ at the front face. All such

warning labels shall be riveted to the shroud plates.



The main three phase, neutral and earth bus bars shall extend throughout the entire length of

panel. They shall be with predrilled holes at the ends for future extensions.

When future space provision indicated in the drawings, The space shall be complete in all

respects including fixing arrangement, bus bar connections, shrouds etc, (except the breaker).

The bus bars shall be suitably extended, drilled and provided with required bolts and nuts to

connect the external cables to the switchgear.

All bolts, nuts used for bus bar connections shall be of suitable size and grade.


panels. All clearances and creepage distances shall be in accordance to IEC439-1 standards.

The complete bus bar design shall be based on 50° C ambient and shall be designed to with stand

the temperature rise inside the enclosure.





Sub Main Distribution Board (SMDB)

General

The contractor shall supply and install the Sub Main Distribution Board(s) (SMDB) as shown on

the drawings and as herein specified.

The components used in the sub main distribution board shall comply to the specification

described under Components for Panel Boards in this section.

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The SMDB shall be branded type supplied from original manufacturer. The panel builder shall

only fit the breakers on the standard bus bar assembly. Minor adaptations like extension of bus

bars to facilitate cable terminations shall be done by the panel builder as required.


The SMDB shall be assembled by the Franchised Panel Builders of the approved manufacturer.

The franchised panel builder shall have a minimum of 5years experience under the franchisee

agreement.

Type Test Certificate shall be submitted for the SMDB from the manufacturer.

SMDB shall be approved by the local electricity authority.




verification.

The SMDB shall be factory tested by the manufacturer at their works prior to delivery to the site.


to the site.





SMDB Assembly

The SMDB shall be factory-built type in compliance with the IEC 439-1 and BS5486 to



Unless otherwise specified, the standard index shall be IP41 or more as defined in IEC529

standard.

The rated operational voltage of the SMDB shall be up to 690V AC.

The rated insulation voltage of the SMDB shall be up to 1000V AC / 750V DC.

The SMDB shall be designed to have a continuous current rating and minimum short circuit

rating as specified in the drawings.

SMDB shall be of MCCB distribution board type with a prefabricated fully shrouded ASTA

certified bus bar assembly and shall readily accept the manufacturers circuit breakers.

The enclosure shall be of folded and welded construction fabricated out of minimum1.5mm

electro galvanized steel sheet to form a cubicle. Hinged door shall be provided for access to the

operational knobs of the circuit breaker. Removable gland plate shall be provided at the bottom of

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the enclosure. It shall be of floor mounting / wall mounting (as required) with front access and

suitable for bottom / top entry of cables .

Door shall be equipped with integral locks. Keys shall be common for all such locks.

Wherever required a metering module from original manufacturer shall be added to the top of the

cubicle to accommodate the meters indicated in the drawings.

Where additional cabling space is required, an extension module for cabling space from original

manufacturer shall be provided.

All door & mounting plate shall be effectively connected to the earth bar by means of flexible

wire.


required.

Panel shall be of front access type for the purpose of access to all the components, and also for

the purpose of cable terminations.




plates.





Form of construction shall comply to Form –2 as per IEC 439-1 standards or as specified in the

drawings.



different ratings within its frame size without changing the connection bus bars. Circuit breakers

can be either plug-in type or bolt-on type.


current.

Warning labels shall be provided wherever required.




respects including fixing arrangement, bus bar connections, shrouds etc, (except the breaker) and

shall be provided with a blank plate cover to avoid accidental access to the bus bars.

All bolts, nuts used for bus bar connections shall be of suitable size and grade.


panels. All clearances and creepage distances shall be in accordance to IEC439-1.


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Neutral and Earth bus bars shall be provided at location convenient to connect the cables.

Labelling of the panels, circuit / feeder description, components etc. shall be done in a approved







Final Distribution Board (DB)

General

The contractor shall supply and install the Final Distribution Board(s) (DB) as shown on the

drawings and as herein specified.

The components used in the distribution boards shall comply with the specification described

under Components for Panel Boards in this section.



The DB shall be branded type supplied from original manufacturer. The panel builder shall only

fit the breakers on the standard bus bar assembly. Minor adaptations like extension of bus bars to

facilitate cable terminations can be done by the panel builder as required.


The DB shall be assembled by the Franchised Panel Builders of the approved manufacturer. The

franchised panel builder shall have a minimum of 5years experience under the franchisee

agreement.

Type Test Certificate shall be submitted for the DB from the manufacturer.

DB shall be approved by the local electricity authority.




verification.

The DB shall be factory tested by the manufacturer at their works prior to delivery to the site.


to the site.





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DB Assembly

The DB shall be factory-built type in compliance with IEC 439 and BSEN60439 standards with

regard to construction and with IEC 529 with regard to degree of protection of the enclosures.

Unless otherwise specified, the standard index shall be IP31 or more as defined in IEC529

standard.

The rated operational voltage of the FDB shall be up to 690V AC.

The rated insulation voltage of the FDB shall be up to 1000V AC / 750V DC.

The DB shall be designed to have a continuous current rating and minimum short circuit rating as

specified in the drawings at ambient temperature of 50° C.

DB shall be of MCB distribution board type with a pre fabricated fully shrouded short circuit

tested bus bar assembly complete with the manufacturers circuit breakers.

The enclosure shall be of folded and welded construction fabricated out of minimum1.2mm

electro galvanized steel sheet to form a cubicle. Hinged door shall be provided for access to the

operational knobs of the circuit breaker. Closed knock out type opening shall be provided at top,

bottom and at the sides for cable glands and conduits.

Unless otherwise specified DB shall be of Recessed / flush type, However the requirement of

surface or recessed type shall be coordinated with the construction contractor prior to supply of

the DB to the site.

Door shall be equipped with pull on type metallic latch kind of lock with out keys.

Where additional cabling space is required or cable glands are used, an extension module for

cabling space from original manufacturer shall be provided.

All door & mounting plates shall be effectively connected to the earth bar by means of flexible

wire.


required, without the risk of accidental contact to the live bars / breaker terminals.

DB shall be of front access type for the purpose of access to all the components, and also for the

purpose of cable terminations.


cables and wires .







different ratings up to 63Amps either 3pole / 1pole without changing the connection of bus bars.

Outgoing circuit breakers can be either plug-in type or bolt-on type.

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Calculations shall be submitted to prove the adequacy of the size of the bus bars for the short

circuit and rated current.

Warning labels shall be provided wherever required.

All warning labels shall be of anodized aluminum or special PVC material, front engraved type



respects including fixing arrangement, bus bar connections, shrouds etc,(except the breaker) and

shall be provided with a blank plate cover to avoid accidental access to the bus bars.

All bolts, nuts used for bus bar connections shall be of suitable material, size and grade.


panels. All clearances and creepage distances shall be in accordance to IEC439-1.



Solid neutral and earth bus bars shall be provided at convenient location to connect the external

cables / wires.

Labelling of the panels, circuit / feeder description, components etc. shall be done in an approved







Components for Panel Boards

General

The following describes the general description of the components used in the panel boards (LV

Panel, MDBs, SMDBs, FDBs, ATS, MTS, Starter Panels, Capacitor banks etc.) as applicable.

The panel builder shall select and provide the appropriate type of components using the

specification listed below, in accordance with the contract drawings / documents and applicable

international & local standards.

a. Air Circuit breakers(ACBs)

Air circuit breakers (ACBs) shall be suitable for controlling loads at 50deg. c ambient and shall

comply with IEC 947-2 and BS 4752. ACB’s shall be suitable for withstanding the short circuit

current as shown on the drawings.

Type test certificate shall be submitted for short circuit withstand capacity of the breaker.

All breakers shall be 3pole or 4 pole and with electrical / mechanical interlock (where ever

indicated) and as shown on the drawings.

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The breaking capacity performance certificates shall be available for category B to the above

mentioned standards. The test shall be carried out with a breaking performance during operation

(Ics) and admissible short time withstand (Icw) equal to the ultimate breaking capacity (Icu).

All air circuit breakers shall be reverse fed without reduction in performance.

All air circuit breakers shall have a rated operational voltage of 690V AC and rated insulation

voltage of 1000V AC.

All circuit breakers shall be fully tropicalized (T2) as standard.

On 4-pole version, the neutral pole shall have the same current rating as the other phase poles

from 800 up to 4000A and N/2 from 5000 up to 6300A.

All air circuit breakers main contact shall be encased in a reinforced polyester casing and offer

double insulation from the operators on the breaker front face. The circuit breaker also shall offer

total insulation of the control part with respect to the power part.

All the air circuit breakers shall be of horizontally isolated draw out pattern air break type. The

circuit breakers shall be provided with interlocks to ensure that :

Racking in or out the circuit breaker with the breaker in ON position shall trip the circuit breaker.

The circuit breakers cannot be closed in the service position with out completing the auxiliary

circuits between the fixed and the moving positions.

a. The draw out type breakers shall have three distinct positions and they are disconnected, test

and connected positions.

b. The draw out operation shall be possible through a closed door.

c. Three positions of the moving part shall be possible :

connected position - all auxiliary and main circuits engaged

test position - all auxiliary circuits engaged all main circuits disconnected

isolated position - all circuits disconnected.

Insulated safety shutters shall be provided over the incoming and outgoing main circuits and over

the auxiliary circuits. An interlocking shall be provided to prevent insertion of a circuit breaker

having a rating higher than the current rating of the fixed part, into that fixed part.

The breakers shall operate via stored energy mechanism for instantaneous closing and opening.

The mechanism shall be charged electrically. Closing and opening operation shall be either from

the local push buttons on the circuit breaker or by remote control.

The operating mechanism shall be of stored energy spring type with a closing time of less than

or equal to 80ms.

The springs shall be automatically charged by an electric motor. The maximum time to charge the

springs shall not exceed 4 seconds. It shall also be possible to charge the springs manually.

All auxiliaries shall be accessible from the front, mounted in a separate compartment insulated

from the power circuits. They shall be secured by single screw, adjustment free and can be fitted

on site.

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Contacts shall be designed to be maintenance free in normal usage. The main contacts shall be

equipped with an indicator in order to allow its wear level to be checked without measurements

nor specific tools.

A mechanical indicator shall be provided on the front face of the air circuit breaker which is

linked to the main contact assembly in such a manner as to positively indicate the contact status,

it shall only be possible for "OFF" to be indicated when all contacts are parted and isolated by the

required distance.

Arc chutes shall be common on the whole range and removable on site to allow inspection of arc

chutes and main contacts.

All electrical auxiliaries including the motor spring charging mechanism shall be field adaptable

without adjustment or the necessity for any tool (except a screwdriver). They shall be fitted into a

compartment which under normally loaded conditions has no metalwork energized from the main

poles exposed with it. Any adaptation carried out thus shall not increase the breaker size. It shall

be possible to connect all auxiliary wiring from the front face of the air circuit breaker, this wiring

shall be taken through a set of disconnecting contacts, so that all auxiliary wiring is automatically

disconnected in the isolated position.

Mechanical indicators shall be provided on the front of the air circuit breaker to indicate the

following which shall be clearly visible :

Main contacts closed "ON"

Main contacts open "OFF"

Springs charged

Springs discharged

Circuit breaker in "connected" position (draw out only)

Circuit breaker in "test" position (draw out only)

Circuit breaker in "disconnected" position (draw out only).

ACB’s shall be provided with solid state type microprocessor based over current & earth fault

relays, which shall use digital programming techniques for highest protection accuracy and be

integrated as part of the circuit breaker. The current transformers / sensors and the wiring shall be

integrated within the case and shall be self powered. The current sensors shall be located within

the case of the circuit breaker. The over current relay shall have a wide adjustment range to allow

flexibility of setting on site. The trip unit shall measure the true RMS value of any wave form of

current. The control unit shall be equipped with a push to reset mechanical indicator, for anti-

pumping function.

Characteristics of the trip units shall be as given below :

Long time protection (LT)

Adjustable (in steps of 4% ) from 0,4 to 1 of the sensor rating (In).

Time delay adjustable from 15 to 480 seconds (at 1.5 times the long time setting).

Short time protection (ST)

Adjustable (in steps of 4% ) from 0.4 to 15 times the long time protection setting (Ir).

Time delay adjustable from instantaneous to 0.4 seconds.

Time inverse characteristic (I2t) may be switched in order to improve discrimination .

Instantaneous (INST)

Adjustable from 2 times up to at least 20 times the rated current for sensor ratings up to 2000 A

and at least 10 times the rated current for sensor ratings above 2000Amps.

Where indicated in the drawings the trip unit shall be equipped with an earth fault option.

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b. Moulded case circuit breakers(MCCBs)

The moulded-case circuit breakers shall comply with IEC 947-1, IEC947-2 and BS4752

standards. They shall be of category A with a rated service breaking capacity (Ics) equal to the

ultimate breaking capacity (Icu) - on the operational voltage range for the ratings up to 630A.

Moulded case circuit breakers (MCCBs) shall be fitted with thermal over load and instantaneous

magnetic short circuit protection.

All the mccb shall be of current limiting type and shall not require any backup fuses. Mccbs shall

be fully fault rated for the duty they perform.

Mccbs shall have a rated operational voltage of 690V AC and have a rated insulation voltage of

750V AC.

The moulded-case circuit breakers shall provide class II insulation (according to IEC 664

standard) between the front and internal power circuits.

The moulded-case circuit breakers shall be designed for both vertical and horizontal mounting,

without any adverse effect on electrical performance. It shall be possible to supply power either

from the upstream or downstream side.

For maximum safety, the power contacts shall be insulated in an enclosure made of a

thermosetting material from other functions such as the operating mechanism, the case, the trip

unit and auxiliaries.

The operating mechanism of the moulded-case circuit breakers shall be of the quick-make, quick-

break type with fault tripping overriding manual operation.

All poles shall operate simultaneously for circuit breaker opening, closing and tripping.

The moulded-case circuit breakers shall be actuated by a toggle or handle that clearly indicates

the three positions: ON, OFF and TRIPPED. The operating mechanism shall be designed such

that the toggle or handle can only be in OFF position (O) if the power contacts are all actually

separated. Isolation shall be provided by a double break on the main circuit.

The moulded-case circuit breakers shall be able to receive a device for locking in the "isolated"

position, with up to 3 padlocks.

The moulded-case circuit breakers shall be equipped with a "push to trip" button in front to test

operation and the opening of the poles. The circuit breaker rating, the "push to trip" button,

outgoing circuit identification and the contact position indication must be clearly visible and

accessible from the front, through the front panel or the door of the switchboard.

The moulded-case circuit breakers shall be capable of greatly limiting currents. For short-circuits,

the maximum thermal stress I2t shall be limited to 10

6 x A

2S for ratings up to 250Amps and 5 x

106

x A2S for ratings between 400Amps to 630Amps.These characteristics shall allow high

cascading performance with moulded-case or miniature circuit-breakers downstream.

The moulded-case circuit breakers shall comprise a device, designed to trip the circuit-breaker in

the event of high-value short-circuit currents. This device shall be independent of the thermal-

magnetic or electronic trip unit.

The moulded-case circuit breakers, the current ratings of which are identical with the ratings of

their trip units, shall ensure discrimination for any fault current up to at least 25 kA rms, with any

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downstream circuit-breaker having a current rating less or equal to 0.4 times that of the upstream

circuit-breaker.

The electrical endurance of the moulded-case circuit breakers, as defined by IEC 947-2 standard.

The addition / extension of a rotary handle shall in no way affect circuit breaker characteristics.

Only three stable tripping mechanism positions (ON, OFF and TRIPPED) shall be possible with

the direct rotary handle or extended rotary handle or toggle. Isolation shall provide positive

contact indication (ON and OFF) in front. The addition of rotary handle shall not mask or block

device settings.

The moulded-case circuit breakers shall be designed to enable safe on-site installation of

auxiliaries such as voltage releases (shunt and under voltage releases) and indication switches as

follows:

a. They shall be separated from power circuits.

b. All electrical auxiliaries shall be of the snap-in type and fitted with terminal blocks.

c. All auxiliaries shall be common for the entire range.

d. Auxiliary function and terminals shall be permanently engraved on the case of the circuit

breaker and the auxiliary itself.

e. The addition of auxiliaries shall not increase the size of the circuit breaker.

Moulded-case circuit breakers with ratings up to 250 A shall be equipped with thermal - magnetic

trip units of interchangeable types. Moulded-case circuit breakers with ratings over 250 A shall

be equipped with electronic trip units.

Electronic trip units shall comply with appendix F of IEC 947-2 standard (measurement of rms

current values, electromagnetic compatibility, etc.).

All breakers shall be ambient compensated for 400

C and shall be derated for 500

C ambient.

Electronic components shall withstand temperatures up to 125°C.

Electronic and thermal-magnetic trip units shall be adjustable and it shall be possible to fit lead

seals to prevent unauthorised access to the settings.

Protection settings shall apply to all circuit breaker poles.

Characteristics of the trip units of the breakers shall be as given below :

For breakers up to 250Amps equipped with thermal trip units

Adjustable (from 80% to 100% of the current rating) thermal protection.

Fixed magnetic protection for current ratings up to 200 A

Adjustable (from 5 to 10 times the current rating) for current ratings greater than 200 A. It

shall be possible to ensure neutral protection. The tripping threshold shall be equal to that of

the phases, or to a reduced value (generally half of that of the phases).

For breakers above 400Amps equipped with electronic trip unit.long time protection (LT)

Selectable Ir threshold with fourty-eight settings from 40 to 100% of the trip unit rating.

short time protection (ST)

Im threshold shall be adjustable from 2 to 10 times the thermal setting Ir.

the time delay shall be fixed at 40 ms.

instantaneous protection

the threshold shall be fixed (between 12 and 19 times In, depending on the rating)

c. Miniature circuit breakers (MCBs)

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MCB shall comply with IEC 947-2 and BSEN60898.

MCB shall have a rated operational voltage of 240V/415V AC.

MCB shall be modular, Bolt-on or Plug-in type and available in one, two, three or four poles

version. Rating, no. of poles and KA rating shall be as indicated on the drawings.

Unless otherwise indicated on the drawings, the short circuit fault current rating for all the final

circuit MCBs shall be 10KA as per BSEN60898 standards. The KA rating shall be clearly

indicated in the front face of MCB.

MCB shall be reverse fed without reduction in performance.

The operating mechanism of MCB shall be mechanically trip free from the operating handle so as

to prevent the contacts from being held closed against short circuit conditions. MCB shall be of

the “automatic resetting type”.

The individual operating mechanism of each pole of a multi-pole MCB shall be directly linked

within the MCB casing and not by the operating handles.

The operating handle of MCB shall be of the toggle type with possibility of padlocking facility.

Each pole of MCB shall be provided with bi-metallic thermal element for overload protection and

magnetic element for short circuit protection.

MCB Terminals shall be of the tunnel type (IP20) in order to minimize the risk of direct contact.

MCB shall adapt itself to the standard distribution board assembly without any modification.

d. Earth leakage circuit breakers (ELCBs / RCCBs)

ELCB shall comply with BS5243 standards.

ELCB shall have a rated operational voltage of 240V/415V AC.

ELCB shall be modular, Bolt-on or Plug-in type and available in two or four poles version.

Rating, sensitivity and no. of poles shall be as indicated on the drawings.

Unless otherwise indicated on the drawings, the sensitivity of the ELCBs at the incomer of the

DB shall be 100mA.

ELCB shall be reverse fed without reduction in performance.

The operating handle shall be of the toggle type with possibility of padlocking facility. The

operating toggle shall be one, irrespective of 2 pole or 4 pole version

The ELCB shall be with a test button built in on the front face of the ELCB to test trip the ELCB

whenever required.

The operating mechanism shall be mechanically trip free from the operating handle so as to

prevent the contacts from being held closed against fault conditions.

Terminals shall be of the tunnel type (IP20) in order to minimize the risk of direct contact.

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ELCB shall adapt itself to the standard distribution board assembly without any modification.

e. Earth leakage relays (ELRs)

ELR and sensors shall comply with IEC 364 and IEC 755 standards.

ELR shall be modular type. ELR shall be suitable for rail mounting or panel front mounting.

ELR shall be residual current operated protection relay and core balance current transformer

operated type.

ELR shall have a adjustable earth leakage sensitivity setting and shall be set to the sensitivity as

shown on the drawings.

ELR shall have a adjustable tripping dime adjustment and shall be set to the time as shown on the

drawings.

ELR shall have a test push button built in on the front face of the relay to test the ELR whenever

required.

ELR shall be of manual reset type and shall have a reset push button built in on the front face of

the relay to reset after a earth leakage trip. Wherever required, it shall be possible to have a

remote reset type of relay.

ELR shall have a built in LEDs on the front face of the relay to indicate the relay is energised and

relay trip status.

ELR shall have a sealable, transparent, hinged lift off type protective cover on the front to avoid

unintentional access to the relay. All adjustment knobs, test / reset push buttons, LED indictors

shall be behind this transparent cover.

All terminals of the ELR shall be of screw type.

Core balance current transformer (CBCT) shall be provided for each relay.

Core balance current transformers shall be installed on the power cables and hole the sizes of the

CBCT shall be suit the cable sizes. All such transformers shall be supplied with suitable

installation accessories.

Special screened cables shall be used for interconnection between the CBCT and ELR.

Where ELR is indicated in the drawings, unless otherwise indicated, the trip contact shall be

wired to the shunt trip coil of the circuit breaker to which it is connected to, so as to trip the

circuit breaker in case of earth leakage.

Unless otherwise indicated, ELR and CBCT shall be two separate units.

f. Metering Equipment

Current transformer

The current transformer shall comply with IEC 185 and shall be suitably rated and designed to

carry out appropriate function.

Current transformer construction shall be cases of self extinguishing poly carbonate according to

UL94 shall include sealable terminal cover made of poly carbonate.

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Current transformer characteristics shall be as given below :

Rated secondary current: 5A.

Rated insulation level: 3KV, 50Hz for 1 minute.

Rated continuous thermal current: 1.2 times rated current.

Rated short time thermal current: 60 times rated current.

Rated dynamic current: 2.5 times rated shorted thermal current.

Thermal class of insulation : E (120° C) according to IEC 185.

All the secondary wiring shall be routed through the C.T shorting terminal to facilitate calibration

of the equipments connected to the current transformer (Except for KWH meter circuit).

Meters

Meters – Those shall include Ammeter, Voltmeter, Frequency meters, Power factor meter, KWH

meters, etc.

All indicating instruments shall comply to IEC 181.

The meters shall be in a case of steel sheet with base of self extinguishing thermoplastic. Scales

shall be clearly marked with black lettering and graduations on a white back ground. Instruments

of same type and range shall have identical scales and of interchangeable type. The size of the

instruments shall be of 72 x 72mm min.

Accuracy class of the instrument shall be 1.5 according to IEC-51 for indicating instruments.

Ammeters & voltmeters

The ammeters and voltmeters shall be of 96mmx96mm Square or 72mmx72mm square (as

applicable) , 90deg. scale, moving iron type with silicone oil damping. Pivot suspension with

spring loaded jewel bearings for vibration and shock resistance.

Meter characteristics shall be as given below :

Over load capacity: 1.2 times nominal current continuously and 10 times nominal current for

5secs.

Rated insulation voltage: 650V.

Test voltage : 2kV, 50Hz during 1minute according to IEC 414. -

Response time : Approximately 1second.

Frequency Meter

The Frequency meter shall be of 96mmx96mm Square or 72mmx72mm square (as applicable),

90deg. scale, moving coil type with electronic transducer, movement with hair springs for the

creation of the restoring torque. Pivot suspension with spring loaded jewel bearings for vibration

shock resistance.


Over load capacity: +/- 15%.


Test voltage : 2kV, 50Hz during 1minute according to IEC 414.

Power factor meter

OF 30

The power factor meter shall be of 96mmx96mm square, 90deg. scale. Eddy current damping

with pivot suspension with spring loaded jewel bearings for vibration shock resistance.


Over load capacity: 1.2 times nominal current continuously and 10 times nominal current for

5secs.


Test voltage : 2kV, 50Hz during 1minute according to IEC 414.

Response time : Approximately 1seond.

KWH meter

KWH meter shall be as per requirements of the LOCAL ELECTRICITY AUTHORITY.

Calibrated KWH meter approved by Local Electricity Authority shall be provided.

CT Ratio, Wiring and Installation of the KWh meter shall be as per Local Electricity authority

requirements.

Wherever required or indicated on the drawings the KWh meter shall be provided in a pad

lockable meter cabinet. The meter cabinet shall be with a view window to view the meter reading.

g. Indication lamps

Indicating lamps shall be rated to withstand not less than 20% continuous over voltage and shall

be rated to ensure long life. The applied voltage shall not exceed 80% of the lamp rated voltage.

Lamps shall well be ventilated and the design shall permit removal lamp glass and bulbs from the

front of the unit.

The indicating lamps shall of matching design to push buttons arranged for single hole fixing and

of small body size to allow close grouping.

All terminals shall be of screw type.

Indicating lamps on 240V supply shall of the direct bulb type operating at a reduced voltage not

exceeding 10volts to give long bulb life and be of LED type or as approved by the engineer.

Indicating lamps shall have shallow bezels which incorporate plastic lenses of the specified

colour.

Engraved legend plates shall be fitted with all indicating lamps.

The engraved legend plates shall be made from special flexible pvc sheet or anodised aluminium

sheet. The minimum characters height on the engraved legend sheet shall be 3mm. The text shall

be black colour on a white background.

The colour of the lenses shall be as per the specific function and in compliance with applicable

IEC standard.

The IP index of the front face of the indication lamp shall be IP55 as minimum.

h. Push Buttons

OF 30

Push buttons shall of matching design to indicating lamps arranged for single hole fixing and of

small body size to allow close grouping.

Unless otherwise specified, the push buttons shall be of spring return type. Wherever used for

emergency shutdown / stop purpose, push button shall be of red colour, mushroom head, push to

stop, stay put, turn or pull to release type.

Push buttons shall accept contact blocks either clipped or screwed to its back holder.

Add on contact blocks shall be of N/O or N/C type as required and all such contacts shall be rated

for 5A inductive.

Push buttons shall be possible to include up to 8nos. of contact blocks.

All contact block terminals shall be of screw type.

Push buttons shall be of different colour as per their function and in compliance with applicable

IEC standard.

Engraved legend plates shall be fitted with all push buttons.


sheet. The minimum characters height on the engraved legend sheet shall be 3mm.The text shall


The IP index of the front face of the push button shall be IP55 as minimum.

i. Selector Switches

Selector Switches shall of matching design to indicating lamps / push buttons arranged for single

hole fixing and of small body size to allow close grouping.

Selector switches shall be of 2 or 3 position type as required and as shown on the drawings.

Selector switches shall accept contact blocks either clipped or screwed to its back holder.

Add on contact blocks shall be of N/O or N/C type as required and all such contacts shall be rated

for 5A inductive.

Selector switches shall be possible to include up to 8nos. of contact blocks.

All contact block terminals shall be of screw type.

Engraved legend plates shall be fitted with all selector switches.


sheet. The minimum characters height on the engraved legend sheet shall be 3mm.The text shall


The IP index of the front face of the selector switch shall be IP55 as minimum.

j. Contactors

Contactors shall comply to IEC158-1 and 947-4 standards

Contactors shall be shall be suitable for rated insulation voltage up to 1000volts.

OF 30

Contactors shall be suitable for operation at 55deg.C.

Contactors shall be of AC3 duty and of 3 pole type unless otherwise specified.

Contactors coils operational voltage(Uc) shall be between 0.8 to 1.1Uc and drop out at 0.3 to

0.6Uc. The closing time for the contactor rating up to 100Amps shall not exceed 40ms and the

opening time shall be with in 25ms. Rated breaking and making capacity of the contactor shall

not be lower than 8/10times of rated operational current up to 100amps and 6/8 times of

operational current.

Contactors, when used in motor starters, shall be co-ordinated with the upstream protection for

TYPE 2 co-ordination.

It shall be possible to easily replace the coil of the contactor.

Contactors at any time shall accommodate auxiliary contacts or pneumatic time delay blocks on

front face and atleast one auxiliary contact block on each side of the contactor.

Contactors for capacitor switching shall of capacitor switching type contactors suitably rated for

the capacitor current. It shall be fitted with a block of early make poles and damping resistors,

limiting the value of the current on closing to 80In max. This current limitation increase the life

of all the components of the installation, in particular that of the fuses and the capacitors.

k. Over load relays

Overload relays shall comply to IEC947-1and 947-4 standards.

Overload relays shall be shall be suitable for rated insulation voltage up to 1000volts.

Over load relay shall be suitable for operation at 55deg.C.

Over load relay shall be three pole bimetal thermal over type and be equipped with the bimetal

element on all the three poles.

Unless otherwise specified the overload relays shall always be of Class 10A.

Overload relay setting range shall be adjustable within a range and shall be selected to suit the

requirement.

Overload relays shall be with suitably rated N/O & N/C contacts.

Over load relays shall be with a auto / manual mode selector to select the type of fault reset.

Unless otherwise specified the reset shall be always selected to manual.

Over load relays shall be with a test button accessible with a screw driver to allow the checking of

control wiring.

Over load relays shall be with a trip indicator.

Wherever required it shall be fitted with a external reset push button (mechanical reset) or an

electric reset facility as indicated on the drawings.

l. Control relays

Control relays shall be with minimum 4nos. normally open or normally closed contacts. All

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contacts shall be rated for 6Amps inductive.

Control relays shall be of plug in type completely enclosed in a hermetically sealed transparent

casing.

Control relays shall be complete with round or flat pin base, which shall be suitable for rail

mounting

Operation voltage of the control relay shall be to suit requirement.

Control relay shall be provided with a built in Led indicator or a Mechanical flag to indicate the

status.

Control shall have a lift off or push type test button to operate the relay mechanically, whenever

required. It shall be possible to leave the relay continuously in on position by using this test

button.

The base shall be of rugged construction and shall not allow mismatch between the relay and base

pins. The back of the relay base shall be completely enclosed.

Each relay and base shall be supplied with a metallic clip to hold the relay in its position.

Wherever more than one operating voltage of relays is used in a particular site / panel, the type of

relay and base shall be unique for particular operating voltage but shall be different for other

voltages.

m. Terminals

Terminal blocks shall be of molded anti cracking type, clipped on to a common rail.

Terminal blocks shall be grouped according to the working voltage, power circuits and control

circuits.

Terminals which are energized with mains supply shall be suitably shrouded and indicated.

Terminal shall be selected to suit the rating, cable / wire sizes and application.

Unless otherwise specified, minimum size of the terminal shall be to suit 2.5sqmm cable / wire.

White ferrules shall be provided on each terminal for circuit identification, numbered according

to the wiring diagrams.

Approximately 20% spare terminal shall be provided on each group of terminal block.

n. Panel Heater

Thermostatically controlled heaters to prevent condensation and assist ventilation shall be

provided wherever required.

The rating of any one of the unit shall not exceed 60Watts and the surface temperature of any part

there may be contacted accidentally shall not exceed 65° C.

The heaters shall be so situated that no detoriaration can be caused to any of the apparatus or

wiring in the cable.

OF 30

The heating circuit shall be independently fused and controlled by a suitably labeled selector

switch mounted in an accessible position with in the cubicle.

o. Panel Wiring

All internal and control wiring shall be 600/1100Volt PVC insulated multi stranded copper wires

to BS 6004.

All cables shall be adequately rated and shall not be less than 1.5sqmm.

All cables shall run on pvc cable ducts with removable cover.

Each cable shall be properly terminated at both ends with wire loops, using pre-insulated blade

type or spade type terminals.

Not more than two wires shall be allowed to connect in each terminal.

Where wiring is carried across door hinges, it shall be enclosed in a special flexible tube and be

looped to permit the opening of doors and removal of components for inspection without

disconnecting and over flexing of the cables.

Plastic ferrules or tags inscribed with correct numbers shall be fitted on all wires correspond with

circuit number and diagram.

Systematic use shall also be made of different colours of wire.

VOLTAGE STABILIZER

The contractor shall supply, install and commission the suitably rated voltage stabilizer to feed

power to the fuel system control panel.

The stabilizer shall be contained in a ventilated steel cabinet with back cable entries. The cabinet

shall be finished with double powder coating.

The stabilizer shall be supplied with voltmeter, ammeter, output MCB and indicator lamps,

meeting the criteria set out below.

Type Electronic Servo Motor Control

Output Accuracy ± 1%

Input variation ± 20%

Frequency 50 Hz

Wave form distortion <0.2%

Ambient temperature -10 to 60 Deg.C

Cooling System Air convection up to 20KVA

No. of Phase 1Ph. or 3Ph.- As specified in the drawings

Output Load KVA rating - As specified in the drawings

Protection Against - Over Load, Short circuit, Voltage surge

and Voltage spike.

Interference Free of Audio/Video Interference

The stabilizer shall be installed properly on a custom made stand. If rack mounting type stabilizer

is used, it shall be installed in a cabinet / panel and the panel shall be properly ventilated.

Stabilizer shall be with an integral By Pass facility (By Pass Switch).

OF 30

Stabilizer shall be with an integral voltage surge suppressor (Surge Arrestor).

EXECUTION

Installation

All equipments shall be installed as per equipment layout drawings, relevant standards, standard

procedures and in accordance with manufacturing instructions.

Conduits for cable installation shall be of material and size as shown in the drawings. Conduits

above false ceiling maybe surface (or) concealed type. However, it shall be concealed type on

finished walls

Cables for system installation shall be as per manufacturer recommendation and of approved type

complying with relevant codes and standards/local authority requirements.

Inspection, Testing and Commissioning

Inspection, testing and commissiong shall be done after completion of installation system.

Contractor/supplier shall submit detailed procedures for inspection, testing and commissioning of

the system for COMPANY’s approval and shall complete inspection, testing & commissioning

accordingly.

Contractor shall also complete the inspection, testing and commissioning as per the “Inspection

Checklist/Report” formats providing elsewhere in the Contract Document (Volume 2)

All main and submain panel boards shall undergo the following test before dispatching and a test

certificate shall be forwarded for the same.

Primary injection test for all circuit breakers and meters.

Secondary tets for all protective relays.

Millivolt droptest

Insulation test

Function test

All such tests shall be witnessed by COMPANY or it shall be carried out by an independent

testing authorities.

After installation and levelling, render the entire switchboard rodent proof by any means of steel

plates

Installation of switchboard shall be fully in accordance with THE COMPANY requirements.

Switchgear and distribution boards shall be surface mounted/free standing type and shall be

mounted on the building structure by means of suitable mild steel straps or angle iron frames.

Where distribution boards or switchgear are required to be directly attached to brickwork etc., the

fixing shall be by means of grouted in bolts, or bolts of the expansion type.

Any live metal in the distribution board shall be screened with insulation material, so that circuit

breakers can be replaced without any danger to the operator.

OF 30

The circuit breakers shall be situated to allow wiring to be carried out with sufficient slack to enable

them to be removed for inspection without disconnecting any circuit wiring.

All main, submain and final distribution boards shall have a spare capacity and shall also be

provided with enough spare breaker as shown on the drawings.

The contractor shall supply and install all panel board with the related voltmeters, ammeters and

energy meters of a type that meets with ADDC approval.

Where single core cables enter or leave any item of metal clad switchgear, distribution gear, etc., the

cable cores shall all pass through the same aperture in the enclosure or case of the unit concerned, to

avoid the setting up of eddy currents. Where separate holes are provided by the manufacturer for

the cables, the holes shall either be cut out to form a continuous slot, or alternatively the holes shall

all be joined together with saw cuts through the solid metal separating the holes. In all cases end

plates shall be of non-ferrous metal.

A special termination arrangement shall be provided to Engineer and ADDC approval at the

submain and main panel boards wherever the cable size exceeds the breaker terminal capacity.

Routine tests to standards shall be carried out. Evidence that type test have been carried out

provided they are relatively to the configuration of the equipment offered, may be acceptable to

THE COMPANY and shall be made available.

A full visual check and electrical functional test shall be carried out on all apparatus and every

circuit. All wiring shall be inspected. It shall be verified that the FBA is fully in accord with the

requisition. Circuit breakers shall be closed and tripped at their rated minimum and maximum trip

and close supply voltage. Primary and secondary injection tests shall be done on protection

relays and CT circuits and indicating and metering instruments. All labels shall be checked.

The test procedure shall be as follows:

a. Visual inspection to verify degree of protection creepage and clearance distances.

b. All conductors and cables are checked for proper routing and all devices for proper mounting.

c. Check effectiveness of all mechanical devices, e.g. handles, locks, interlocks, operating

devices, etc.

d. Check panel conformity to drawing and COMPANY requirements.

e. Megger test all main circuit through to final terminals. Insulation resistance shall exceed 10

meghoms. Record all measurements.

f. Flash test all main circuit at 2.5 KV for one minute. Record leakage current.

g. Repeat megger test to verify insulation resistance has not been affected by the dielectric test.

h. Continuity tests of each circuit.

i. Function test of all circuit breakers switches, contacts, etc. and every circuit to verify correct

operation.

j. Primary and secondary injection tests of all relays, CT’s and indicating and metering

instruments.

Prior to energizing the switchboards, perform the following checks on site:

a. Operate the equipment through all design functions, including remote operation, actuation of

alarm and indicating devices, mechanical and electrical tripping and closing and operation of

the protective devices.

b. Insulation resistance measurements on the buses, phase to phase and phase to ground, with all

breakers in the fully connected position and contacts open.

c. Control circuit insulation resistance to ground.

d. Inspect all relays and protective devices, and verify settings in accordance with the

manufacturer’s instructions or the information in the Coordination study.

e. Inspect current transformers and relays for correct polarity of connections and the installation

of jumpers on unused current transformer circuits.

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f. Simulate the operations and check the logic of interlocks.

g. Manually close and trip each breaker checking and adjusting the main contact alignment and

wiring action in accordance with the manufacturer’s instructions.

h. Check the phasing on each side tie breaker, before closing.

i. Test protective relay operation for incomer air circuit breakers.

Routine Tests

a. Following routine tests are to be carried out by the switchgear assembler,

b. Inspection of assembly including inspection of wiring and electrical operation.

c. Dielectric test:

d. Checking of protective measures and of the electrical continuity of the protective circuits.

e. Verification of insulation resistance.

END OF SECTION

Electrical Specifications

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