Construction of Taluka Panchayat office building at Kawant Ta. Dist : Chhotaudepur Under CDP-3 (2025-26) (2nd Attempt)

Name Of Work :-

Construction of Taluka Panchayat office building at Kawant Ta.

Dist : Chhotaudepur Under CDP-3 (2025-26)

SPECIFICATIONS FOR ELECTRICAL WORKS IN GOVERNMENT BUILDING

SUBJECT TO THE GENERAL CONDITION OF CONTRACT IN FORCE

1. Wiring Rules:

The installation generally shall be carried out in conformity with relevant Indian Standard Specifications and

code of practices prevalent, Indian Electricity Rules, 1956 and Indian Electricity Act, 1910 as amended from

The definition of terms shall be in accordance with Indian Standard code of Practice for Electrical

wiring Installation IS- 732-1982 except for the definition of point in case of Internal Electrical

Installation. For definition of point wiring and measurement of Electrical works IS-5908-1970 shall be referred

3. Voltage and Frequency of Supply:

All current consuming devices shall be suitable for frequency of 50 C/s and system of voltage meant for

unless otherwise specified.

4. Layout of wiring and its description :

(i) The wiring shall be carried out as per Schedule "power" wiring must be in screwed conduit and

shall be kept separate and distinct from lighting wiring. All wiring must be done on the distribution system

with main and branch distribution boards at convenient centers and without isolated fuses. All conductors

shall be run as far as possible along the walls and ceiling as to be easily accessible and capable of being

thoroughly inspected. The balancing of circuits will be arranged before hand by the Ex. Engineer Electrical

(ii) Within one month of the taking over the installation, the contractor shall supply to the Ex.

Engineer, Elect. Division a complete set of wiring diagrams of the same on drawings to be supplied when

available by the Executive Engineer, Electrical Division, and to the satisfaction of the Ex. Engineer, Elect. Dn.

and these Wiring plans shall be "Drawings" within the meaning of the term as used in the General Conditions

All conductors unless otherwise specified shall not be less than 1.5 Sq. mm for point wiring and

mains Conductors for power and lighting circuits shall be of adequate size to carry the designed circuit load

without exceeding the permissible thermal limits for the installation, and such sizes will be stipulated in

specifications and or drawings.

6.1 All cables shall conform to relevant Indian Standards.

6.2 Conductors of all cable except the flexible cable shall be of aluminium. The smallest aluminium

conductors for the final circuit shall have nominal cross sectional area of not less than 1.5 Sq. mm.

The minimum size of the aluminium conductors for power wiring shall be 4 sq.mm

6.3.1 Conductors of flexible cables shall be of copper. The minimum cross sectional area of such a cables

shall be 14.0193 mm. The flexible cable shall have uniform and adequate insulation.

6.3.2 Unless the flexible cables and conductors are protected by armour or though rubber or PVC Sheath,

these shall not be used in workshops and other places where they are liable to mechanical damage.

6.3.3 Core flexible cables shall be used for connecting single phase Appliances for phase, neutral & earth

7. Fall of Potential:

The cross sectional area of all conductors inside buildings shall be so proportioned to their lengths

that the drop in voltage between main fuses and the farthest point or any lamp shall not exceed three

percent of the voltage of the consumer's With all the consuming devices in use.

7.1 If the CABLE SIZE is increased to avoid the voltage drop in circuit current rating of the cable shall be more than

that for which the circuit is designed. In each circuit or sub circuit every cable shall have a current rating not less

han that of the fuse which protects the circuit or sub circuit respectively for current higher than the

full load current.

8. Ratings of lamps and fans socket out lets: Points and exhaust Ifans

8.1 Incondescent lamps installed in residential and non-residential buildings shall be rated at 60 wattas

& 100 watts respectively.

8.2 Table fans and ceiling fans shall be rated at 60 watts, exhaust fan shall be rated according to their

8.3 5 Amp. socket outlet points and 15 Amp. Sockets outlet points shall be rated at 100 watts and

watts respectively for the purpose of load assessment unless actual values of the load are know or

9.1 Before the installation is commissioned following tests shall be carried out.

(1) Insulation Resistance test

(2) Polarity Tests of Switches

(3) Earth continuity tests

(4) Earth electrods Resistance test

9.2.1.1 The insulation resistance shall be measured between earth and the whole system of conductors or

any section there of with all fuses in place and all switches closed, and except in earthed concentric

wiring all lamps in position or both poles of the installation otherwise electrically connected together

a direct current pressuere of not less than twice the working pressure provided that it need not

exceed. 500 volts for medium voltage circuits where the supply is derived from the three wire D.C. or

a poly phase A.C. System, the neutral pole of which is connected to earth either direct or through

added resistance, the working pressure shall be deemed to be that which is maintained between the

pahse conductor and the neutral.

9.2.1.2 The insulation resistance shall also be measured between all conductors to one pole or phase

conductor of the supply and all the conductors connected to the neutral or. to the order pole or phase

conductors of the supply with all lamps in position and switches in 'OFF' position and its value shall

be not less than in that specified in Sub Clause 9.2.1.3.

9.2.1.3 The insulation resistance in Megohms measured as above shall not be less than 50 Megohms

divided by the number if outlet or when PVC insulated cables are used for wiring 12.5 megohms

divided by number 10f outlets

9.2.1.4 Where a whole .installation is being tested, a lower value than that given by the formula, subject to a

minimum of 1 megohm is acceptable.

9.2.1.5 A preliminary and similar test may be made before lamps, etc. are installed and in this event the

insulation resistance to earth should be not less than 100 megohms divided by the number of outlet

or when PVC insulated. cables are used for wiring 25 megohms divided by number of outlets.

9.2.1.6 The term "Outlet" includes every switch except that a switch combined with a socket outlet,

appliance or lighting fitting is regarded as one outlet.

9.2.1.7 Control rheostat heating and power appliance and electric sign may, if required, be dis-connected

from the circuit during the test, but in that event the insulation resistance between the case or frame

work, and all live parts of each rheostat, appliance and sign, shall be not less than that specified in

the relevant Indian Standard Specification or where there is no such specification shall be not less

than half' a megohm.

9.2.2 Polarity Test :

9.2.2.1 In a two wire installation a test shall be made to verify that all switches in every circuit have been

fitted in the same conductor through' out & such conductor shall be labeled or marked for connection

to the phase conductor or to the non-earthed conductor of the supply

9.2.2.2 In a three wire or a four wire installation a test shall be made to verify that every non-linked single

pole switch is fitted in a conductor which is labeled or marked for connection to one of the phase

conductor of the supply.

9.2.2.3 The installation shall be connected to the supply for testing. The terminals of all switches shall be

tested by a test lamp one lead of which is connected to the earth. Glowing of test lamp to its full

brilliance when the switch is in 'on' position irrespective of appliance in position or not shall indicate

that the switch is connected of the right polarity,

9.2.3 Earth Continuity Test :

The earth continuity conductor including metal conduits and metallic envelops of cables in all cases

shall be tested for electric continuity and the electrical resistance of the same alongwith the earthing

lead but excluding any added resistance or earth leakage circuit breaker measured from the

connection with the earth electrode if any point in the earth continuity conductor in the completed

installation shall not exceed one ohm.

9.2.3.1 Earth Electrode Resistance Test :

Earth electrode Resistance test may be carried out by Meggar Earth Testers containing a direct

reading ohm-meter a hand driven generator and auxiliary electrodes

9.3 On completion of an electric installation (addition and alteration) a certificate shall be furnished by

the contractor countersigned by the certified Supervisor under whose direction supervision the

installation was carried out. This certificate shall be in the prescribed form as given in Appendix-'B' in

addition to the test certificate:! required by Local Electrical Supply Authorities.

10. Joint and looping back:

Unless with the sanction of Ex, Engineer Electrical Divisions all joints in conductor shall be means of

approved mechanical connectors in suitable and approved junction boxes but looping back system

shall be preferable. In wiring unless otherwise specified Phase and live conduct shall be looped at

the switch box where a neutral conductor can be looped from light. fan or socked. In non-residential

buildings, neutral and earth continuity wire shall be brought to each of the switch boards should be of

adequate size to accommodate at least one number of 5 Amps socket outlet and control switch in

Main Switch gears, Switch Board and their location:

11.1 All main switches (other than those of iron clad pattern) carrying current of 10 Amp. and above shall

be fitted for back connections land shall be suitably protected.

11.2 All switches and circuit breakers shall be constructed in accordance with the I.S. 4237-1967. General

requirement for switchgear and control gear for voltage not exceeding 1000 Volts and other relevant

I.S.. provided also that, spring shall be either of phospher bronze or if steel shall be copper or Nickel

plated and that handle shall be so fastened that they do not tend to unscrew or become loose.

11.3 All main switches shall be either of metal clad enclosed pattern or of any insulated enclosed pattern

which shall be fixed at close proximity to the point of entry of supply.

11.4 Switch boards shall not be erected above gas. stoves', or sinks or within 2.5 m of any washing unit in

the washing rooms of laundries or in the bath rooms, lavatories. toilets or kitchens.

11.5 Switch boards, if unavoidably fixed in places likely to be exposed to weather. to drip or to abnormal

moist temperature the outlet casing shall be weather proof and shall be provided with glands or

bushing of adopted to receive screwed conduit according to the manner in which cables are run,

PVC and double flanged bushes shall be fitted in the holes of the switches for entry and exit of wires.

11.6 A switch board not be installed so that its bottom is within 1.25 m above the floor unless the front of

the switch board is completely enclosed by a door or the switch board is located in a position to

which only authorised persons have access.

11.7 Switch boards shall be recessed in the wall if so specified in the schedule of work or in the special

specification. The front shall be fitted with hinged pannel of other suitable material such as bakelite in

wood frame with locking arrangement. the outer surface of door being flush with the walls. Ample

room shall be provided at the back for connections and at the front between the switchgear

mountings and the door.

11.8 Equipments which are on the front of a switch board shall be so arranged that inadvertently personal

contact with live parts is unlikely during the manipulation of switchgears, changing of fuses or like

11.9 No holes other than the holes by means of-which the panel is fixed shall be drilled closer than

cms. from any edge of the panel.

11.10 The various live parts, unless they are effectively screened by substantial barriers of non-

hydroscopic, no-inflammable insulating material, shall be so spaced that space shall not be

maintained between such parts and earth.

11.11 The arrangement of gear shall be such that they shall be readily accessible and their connections to

all instruments and apparatus shall also be traceable.

11.12 In every case in which switches and fuses are fitted on the same pole, these fuses shall be so

arranged that the

fuses are not alive when their respective switches are in the off position.

11.13 No fuses other than fuses in instrument circuit shall be fixed on the back of or behind a switch board

pannel or frame.

11.14 All the metal switchgears and switch boards ~hall be painted, prior to erection with one coat of

antirust primer, After erection they shall be painted with two coats of approved enamel or aluminium

paint as required on all sides wherever accessible.

11.15 All switch boards connected to medium voltage and above shall be provided with 'Danger Notice

Plate' conforming to relevant Indian Standards.

12. Control at Point of Commencement of Supply:

12.1 There shall be a linked main switchgear with fuse on each live conductor of the supply mains at the

point of entry. The wiring through out the installation shall be such that there is no break in the

neutral wire except in the form of a linked switchgear The neutral shall also be distinctly marked. In

this connection Rule 32(2) of the Indian Electricity Rules, 1966 (See Appendix- 'A') shall also be

12.2 The main switchgear shall be situated as near as practicable to be termination of service line and

shall be easily accessible without the use of any external aid.

12.3 On the main switchgear, where the conductor of a two wire system or an earthel neutral conductor

of a multi-wire system or a conductor which is to be connected thereto, an indication of a

permanent nature shall be. provided to identify the earther neutral conductor. In this connection

Rule 32(1 )of Indian Electricity Rules, 1956 (see appendix. 'N) shall be referred.

13.0 Switch Board & Distribution Boards:

Metal clad switch gear shall preferably be mounted on any of the following types of Board.

13.1 Hinged type Metal Boards:

13.1 These shall consist of a box made of sheet metal not less than 2 mm thick and shall be provided with

a hinged cover to enable the board to swing open for examination of the wiring at the back. The

joints snail be welded. A teak wood board, thoroughly protected both inside and outside with good

insulating varnish conforming to IS : 1347-1952 specification for varnish shellac, for General purpose

and of not less than 6.5 mm thickness. shall be provided at the back for attachment of incoming and

outgoing cables. There shall be a clear distance of not less than 2.9 cm between the teak wood

board and the cover, the distance being increased for larger boards in order that on closing of the

cover, the insulation of the cables is not subjected to damage and no short length of cables is

subjected to excessive twisting or bending in any case. The board shall be securely fixed to the wall

by means of rag bolts, plugs or wooden Gutties and shall be provided with a locking arrangement

and an earthing stud. All wires passing through the metal board shall be bunched. Alternatively,

hinged type metal boards shall be made of sheet covering mounted on channel or angle iron frame.

Note: Such type of boards are particularly suitable for small switch-boards for mounting metal-clad

switchgear connected to supply at low voltages.

13.2 Fixed type Metal Boards:

These shall consist of an angle or channel of iron frame fixed on the wall or on floor and supported on the wall at the top

if necessary. There shall be a clear distance of one metre in front of the switch board. If there are attachments of base

connections at the back of .the switch board Rules 51 (1) (c) of Indian Electricity Rules, 1956 is gall apply.

Note : Such type of boards are particularly suitable for large switchboard for mounting large number or switchgears or

higher capacity metal clad switchgears or both.

13.3 Teakwood Boards:

For small installations connected to a single phase 230 volts supply teak wood boards may be

caused as main boards or sub- board. These shall be of seasoned teak or other durable wood with

solid back impregnated with varnish of approved quality with all joints dovetailed.

13.4 In large size medium voltage installations, before proceeding with the actual construction of the boards,

a proper drawing showing the detailed dimensions and design including the disposition of the mountings, which

shall be symmetrically and neatly arranged for arriving at the overall dimensions, shall be prepared and

approved by the Engineer-in-charge. .

13.5 Recessing of Boards:

Where so specified the switch boards shall be recessed in the wall. The front shall be fitted with a hinged panel

of teak wood or other suitable materials. such as bakelite, or with unbreakable glass doors in track wood frame

with locking arrangement, the other surface off the doors being flush with the walls. Ample room shall be

provided at the back for connection and at the front between the switchgear mountings.

13.6 Arrangement of Apparatus:

a) Equipment which is on the front of a switch board shall be so arranged that inadvertently personal contact with

live parts is unlikely during the manipulation of switches, changing of fuses or like operation.

b) No apparatus shall project beyond any edge of panel .No fuse body shall be mounted within 2.5 cm. of any

edge of the panel and no hole other than holes by means of which the panel is fixed shall be drilled closer than

1.3 cms from any edge of the panel.

c) The various live parts, unless they are effectively screened by substantial barriers of non-hydroscopic, non--

inflammable insulating material, shall be so spaced that an arc cannot maintain between such parts and earth.

d) The arrangement of the gear shall be such that they shall be readily accessible and their connections to all

instruments and apparatus snaII also be easily traceable.

e) In every case in which switches and fuses are fitted on the same pole, these fuses shall be so arranged that the

fuses are not alive when their respective switches are in the 'OFF' position.

f) No fuses other than fuses instrument circuit shall be fixed on the back of or behind a switchboard pannel or flame.

13.7 Marking of Apparatus :

a) Where a boards is connected to voltage higher than 250 volts, all the apparatus mounted on it shall be marked in

the following, colours to indicate the different poles or phases to which the apparatus or its different terminals may

have been connected.

Alternating Current Direct Current

Three-phase-red, Three wire system-2 outer wires

Yellow, & blue, Positive red & negative blue

Natural-black Natural-black

Where fuse-wire three phase wiring is done, the neutral shall be in one Colour and the other three wires in

another colour.

b) Where a board has more than one switch each such switch shall be marked to indicate which section of the

installation it controls.

c) All markings required under the rule shall be clear permanent.

13.7.A Main & Branch Distribution Board:

13.8.1 Main and branch distribution boards shall be of any type mentioned in

13.8.2 Main distribution boards shall be provided with a switch or air circuit breaker on each pole of each circuit, a fuse

on the phase or live conductor and a link on the neutral or earthed conductor of leach circuit. The switches shall

always be linked.

13.8.3 Branch Distribution Board:

13.8.3.1 Branch distribution boards shall be provided with a fuse or a miniature circuit breaker or both the

adequate rating setting chosen on the live conductor of each circuit and the earthed neutral

conductor shall be connected to a common link and be capable of being disconnected individually for

testing purposes. At least one spare circuit of the same capacity shall be provided on each branch

distribution board.

13.8.3.2 In residential installations, lights and fans may be wired on a common circuit such sub circuit shall

not have more than total of ten points of lights, fans and socket outlets. The load of such circuit shall

be restricted to 800 watts. If a separate fan circuit is provided, the number of fans in the circuit shall

not exceed ten. Power sub-circuits shall be designed according to the load but in' no case shall there

be more than two outlets on each sub-circuits.

13.8.3.3 In industrial and other similar installations requiring the use of group control of switching operation,

circuits, for socket outlets may be kept separate from fans and lights. Normally fans and lights may

be wired on a common circuit, however, if need is felt separate circuits may be provided for the two.

The road on any low voltage sub-circuit shall not exceed 3000 Watts. In case of new installation, all

circuits and sub-circuits shall be designed by making provision of 20. per cent increase in load due to

any future modification. Power sub-circuits shall be designed according to the load .but in no

case shall there be more than four outlets in each sub- circuits.

13.9 Installation of Distribution Boards :

13.9.1 The distribution fuse-boards shall be located as near as possible to the center of the load they are

intended to control.

13.9.2 These shall be fixed on suitable stanchion or wall and shall be accessible for replacement of fuses.

13.9.3 These shall be of either metal-clad type, or all insulated type. But. if exposed to weather or damp

situations, they shall be of the weather proof type and, if installed where exposed to explodes to

explosive dust, vapour or gas, they shall be of flame proof type.

13.9.4 Where two or more distribution fuse boards feed low voltage these distribution boards shall be :

(1) Fixed not less than 2 m apart or,

(2) Arranged so that it is not possible to open two at a time, namely they are interlocked and the

metal case is marked 'Danger 415 Volts', or

(3) Installed in a room or enclosure accessible to only authorised persons.

13.9.5 All distribution boards shall be marked 'Lighting', 'Power', as the case may be and also marked with the voltage

and number of phases of the supply. Each shall be provided with a circuit list giving details 'of each circuit

which it controls .and the current rating of the circuit and size of fuse-element.

13.9.6 Triple pole distribution boards shall not be generally used for final circuit distribution unless specific approval of

Engineer- in-charge is obtained. In special cases where use of Triple pole distribution boards are inevitable

they. shall be of H.R.C. fuse type only.

13.10 Wiring and Distribution Board:

13.10.1 In wiring a branch board, total load of the consuming devices shall be divided, as far as possible, evenly

between the number of ways of the boards leaving the spare circuit for future extension.

13.10.2 All connections between pieces of apparatus or between apparatus and terminals on a board shall be neatly

arranged in a definite sequence following the arrangement of the apparatus mounted thereon, avoiding

unnecessary crossing.

13.10.3 Cables shall be connected to a terminal only by soldered or welded or crimped lugs using suitable sleeve, lugs

or ferrules unless the terminal is of such a form that it is possible t6 securely clamp them without the cutting

away of cable strands.

13.10.4 All bare conductor shall be rigidly fixed in such a manner that a clearance of at least 2.5 cms. is maintained

between conductor of opposite polarity or phase and between the conductors and any material other than

insulating material.

13.10.5 If required, a pilot lamp shall be fixed and connected through on independent single-pole switch and fuse to the

bus bars of the board.

13.10.6 In a hinged type board, the incoming and outgoing cables shall be fixed at one or more points according to the

number of cables on the back of the board leaving suitable space in between cables and shall also, if possible

be fixed at the corresponding points on the switch board panel. The cables between these points shall be

arranged to form a "U" or "S" shaped loop which shall be of such length as to allow the switch board pannel to

swing through an angle of not less then 90°.

14.0 Capacity of Circuits :

14.1 Lights and fans may be issued on a common circuits and such a circuit shall not have more than a total of ten

points of lights, fan and socket outlets, or a load of 800 watts whichever is less. The power circuits shall be

designed with a maximum of two outlets per circuits generally when load is not known or specified. In non-

residential buildings at important District centers however one outlet per circuit may be preferred. The circuit

shall be designed based on the loading of the circuit where not specified the load shall be taken as 1 KW per

outlet, Where the load is more than 1 KW it should be controlled by a isolator switch or miniature circuit breaker.

15.0 Passing Through Walls and Floors:

15.1 Where conductors pass through walls one of the following methods shall be employed. Care shall be taken to

see that wires pass very freely through protective pipe or box and that the wires pass through in a straight line

without any twist or cross in wires, on other ends of such holes.

(a) A teak wood box extending through the whole thickness of the wall shall be buried in the wall

and casings or conductors shall be carried so as to allow 1 .3 cms air space on three sides,

of the casing conductor.

(b) The conductor shall be carried either in a rigid steel conduit conforming to *IS: 1653-1964 specification

for Rigid Steel conduits of Electrical wiring (Revised) or a rigid non- metallic conduit conforming to *18 :

2509 1963 specification for Rigid Non-Metallic conduits for Electrical Installations, or in a porcelain

tube- of such size which permits easy drawing in, The end of conduit shall be neatly bushed with

porcelain, wood or other approved material.

(c) Insulated conductors while passing through floors shall be protected from mechanical injury by means

of rigid steel conduit (see *18 1653-1964) to a height not less than t.5 m above the floors and flush with

the ceiling below. This steel conduit shall be earthed and securely bushed.

15.2 Where a wall tube passes outside a building so as to be exposed to weather, the outer end shall be belt

mounted and turned down wards, and properly bushed on the open end.

16.0 Fixing to Walls and Ceilings:

Plugs for ordinary walls or ceilings shall be of well seasoned teak or other approved hardwood- not less than

cm long 2.5 cm. square on the inner end and 2 cm. square on the outer end. They shall be cemented into walls

to width 7.5 mm of the surface, the remaining being finished according to the nature of the surface with plaster

or lime punning.

16.1 Where owing to irregular crossing or other reasons the plugging of the walls or ceiling with wood plugs presents

difficulties, the wood casing, wood batten, metal conduit, or cleat (as the case may be) shall be attached to the

wall or ceiling in an approved manner. In the case of new building, wherever possible teak wood plugs shall be

fixed in the walls before they are plastered.

16.2 To achieve neatness, plugging of walls or ceiling may be done by an approved type of asbestos, metallic or a

fiber fixing plug.

17.0 Branch Switches:

Where the supply is derived from a three-wire or four-wire source, and distribution is done on the two wire

system, all branch switches shall be placed in the outer or live conductor of the circuit and no single-phase

switch or fuse shall be inserted in the middle wire, earth or earthed neutral conductor of the circuit. Single-pole

switches (Other than for multiple control) Caring not more than 15 amperes may be of tumbler type which shall

be 'CN' when the handle known is down.

Where conductors are required to be threaded through tubes or channels formed in the metal work of fittings

these must be free from sharp angles or projecting edges and such size that will enable them to be wired with

the conductors used for the final sub Circuits without removing the boarding, taping or outer covering. As far as

possible, all tubes and channels should be of sufficient size to permit 'Looping back; of wires .cables and

flexible cords other than those designed for high temperature shall not be used for wiring fittings except for

portable fit tings. All fittings must have not less than a half inch male nipple. Fittings and lamp holders for gas

filled lamps shall be adequately ventilated.

18.1 Where light fitting is supported by one or more flexible cords, the maximum weight to which the twin flexible

cords may be subjected shall be as follows:

Nominal cross No. & Dia in Max. Permissible

sectional mm of wires. Weight

18.2 No inflammable shade shall form a part of light fitting unless such shade is well protected against all risks of fire.

Celluloid shade or light fitting shall not be used under any circumstances.

18.3 Fitting of Wire :

The use of fitting wire shall be restricted to the internal wiring and the lighting fittings. Where fitting wire is used

for wiring, for the sub-circuit" loads shall be terminated in a ceiling zone or connector from which they shall be

carried into the fittings.

19.0 Lamp Holders :

Lamp holders for use on brackets and the like shall be in accordance with *IS : 1258-1967, specification for

Bayonet lamp holders and all those for use flexible pendants shall be provided with cord grips. All lamp holders

shall be provided with shade carriers. Where center contact edison screw lamp holders are used, the outer or

screw contacts shall be connected to the middle wire, the natural, and the earthed conductor .of the circuit.

20.0 Outdoor Lamps:

External and road lamps shall have weather proof fittings of approved design so as to effectively prevent the

admission of moisture. An insulating distance piece of moisture proof materials shall be inserted in the fittings.

Flexible cord and cord grip lamp holders shall not be used where exposed to whether. In verandahs and similar

exposed situations where pendants are used, they shall be of fixed rod type.

All incandescent lamps, unless otherwise required and suitably protected, shall be hung at a height of not less

than 2.5 m above the floor level. They shall be in accordance with IS : 418 : 1957 specification for Tungsten

Filament General Service electric lamps.

22.0 Fans, Regulators and Clamps:

22.1.0 Ceiling fans :

Ceiling fans including their suspension shall conform to *IS 374-1960 specification for electric ceiling fans and

regulators (Revised) & to the following requirements:

(a) All ceiling fans shall be wired to ceiling roses or to special connector boxes, to which fans rod wires

shall be connected and suspended from hooks or shackles with insulators between hooks and

suspension rods. There shall be no joint in the suspension rod, but if joints be avoidable then such

joints shall be screwed to special couplers of 5 em minimum length and both ends of pipes shall touch

together within couplers, and shall in addition be secured by means of split pins; alternatively, the two

pipes may be welded.

(b) Fans clamps shall be of suitable design according to the nature of construction of ceiling on which

these clamps are fitted. In all cases fan clamps shall be fabricated from tested new metal of suitable

sizes and they shall be as close fitting as possible. Fan clamps for reinforced concrete roots shall be

buried with the casting and due care shall be taken that they shall serve the purpose. Fan clamps for

wood beams shall be of suitable flat iron fixed on two sides of the beam and according to the size and

section of the beam one or two mild steel bolts passing through the beam shall. hold both flat irons

together. Fan clamps for steel joint shall be fabricated from test~ flat iron to fit in rigidly to the bottom

flange of the beam. Care shall be taken during fabrication that the metal does not crack while

hammering to shape. Other fan clamps shall be made to suit the position, but in all cases care shall be

taken to see that they are rigid, and safe.

Note: All fan clamps shall be so fabricated that fans revolve steadily.

(c) Canopies on top and bottom of suspension rod shall effectively hide suspensions and

connections to fan motors, respectively.

(d) The lead-in-wire shall be of nominal cross-sectional area not less than 1.0 mm with copper

and 1.5 mm with aluminium and shall be protected from abrasion.

(e) Unless otherwise specified, the clear distance between the ceiling fan and the floor shall be

less than 2.75 m.

22.2.0 Exhaust Fans :

For fixing of an exhaust fan, a circular hole shall be provided in the wall to suit the size of the frame

which shall be fixed by means of rag-bolts embedded in the wall. The hole shall be neatly plastered

with cement and brought to the original finish of the wall. The exhaust fan shall be connected to

exhaust fan point which shall be wired as neat to the hole as possible by means of a flexible, cord,

care being taken that the blades rotate in the proper direction.

23.0 Attachment of fittings and accessories:

23.1 In other than conduit wiring, all ceiling crosses, brackets, pendants and accessories attached to

walls or ceilings shall be mounted on substantial teak wood block twice Varnished after all fixing

holes are made in them. Blocks shall be not less than 4 cms. deep, Brass screws only shall be used

for attaching fittings and accessories to their base blocks.

24.0 Interchangeability :

Similar part of all switches, lamp holders, distribution fuse-boards ceiling roses, brackets, pendants, fans and all

other fittings of the same type shall be interchangeable in each installation.

25.0 Conduit Wiring System:

25.1.1 Type and size of conduit - All conduit pipes shall b~ conforming to *IS : 1653-1964, furnished with galvanised

or stove enameled surface. All conduit accessories shall be of threaded type and under no circumstances pin

grip type or clamp type accessories be used. No steel conduit less than 16 mm in diameter shall be used. The

number of insulated conductors that can be drawn into rigid steel conduit are given in Table II.

25.1.2 Bunching of cables - Unless otherwise specified, insulated conductors of AC supply and DC supply shall be

bunched 'in separate conduits.

25.1.3 Conduit-joints-Conduit pipes shall be joined by means of screwed couplers and screwed accessories only (*IS :

Specification for Fittings for Rigid Steel Conduits for Electrical Wiring). In long distance stance

straight runs of conduit, inspection type couplers at reasonable intervals shall be provided or running

threads with couplers and jam-puts (in the latter case the bare threaded portion shall be treated with

anti- corrosive preservative) shall be provided. Thread on conduit pipes in all cases shall be between

11 mm to 27 mm long sufficient to accommodate pipes to full threaded portion of couplers or

accessories. Cut ends of conduit pipes shall have no sharp edges nor any or buries left to avoid

damage to the insulation of conductors while puling them through such pipes;

TABLE-II MAXIMUM PERMISSIBLE NUMBER OF 250-V

GRADE SINGLE CORE CABLES THAT CAN BE DRAWN INTO

RIGID STEEL CONDUIT

(CLAUSE 6.5.1.1)

Size of conduit

Nominal Number 16 20 25 32 40 50

Crossectional and (No. of cable Max)

area. Diameter in

* For Cu. Conductors only.

+For AI. Conductors only.

NOTE : 1. The cable shows the maximum capacity of conduits for the simultaneous drawing-in of cables.

The table applies to 250 volts grade cable. The columns headed 'S' apply to runs of conduit which

have distance not exceeding 4.25mm between draw in boxes, and which do not deflect from the

straight by angle of more than 15°. The columns headed 'B' apply to runs of conduit which deflect

from the straight by an angle of more than 15°.

NOTE: 2 In case of inspection type draw-in box has been provided and if the cables is first drawn through one straight

conduit, then through the drawn box, and then through the second straight conduit, such systems may be

considered as that of a straight conduit even if the conduit deflects through the straight by more than 15°.

25.1.4 Protection against dampness In order to minimise condensation or seating inside the tube, all outlets of

conduit system shall be properly drained and ventilated, but in such a-manner as to prevent the entry of insects

as far as possible.

25.1.5 Protection of conduit against rust - The outer surface of the conduit pipes, including all bends, unions, tees

junction boxes, etc., forming part of the conduit system shall be adequately protected against rust particularly

when such system is exposed to weather. In all cases, no bare threaded portion of conduit pipe shall be allowed

unless such bare threaded portion is treated with anti-corrosive preservative or covered with approved plastic

25.1.6 Fixing of conduit - Conduit pipes shall be fixed by heavy gauge saddles, secured to suitable wood plugs or any

other approved plug with screws in an approved manner at an interval of not. more than one meter but on either

side of couplers or bends or similar fittings, saddles shall be fixed at a distance of 30 cm. from the center of such

25.1.7 Bends in conduit - All necessary bends in the system including diversion shall be done by bending pipes, or by

inserting suitable solid or inspection type normal bends, elbows or similar fittings; or by fixing cast iron

inspection boxes whichever is more suitable. Conduit fitting shall be avoided as far as possible. On conduit

system exposed to weather, where necessary, solid type fitting shall be used. Radius of such bends in conduit

pipes shall be not less than 7.5 cm. No length of conduit shall have more than the equivalent of four quarter

bends from outlet, the bends at the outlets not being counted.

25.1.8 Outlets - All outlets for fitting switches etc., shall be boxes, of suitable metal or any other approved outlet boxes

for other surface mounting or flush mounting system.

25.1.9 Conductors- All conductors used in conduits wirings shall preferably be stranded. No single -core cable or

nominal Cross- sectional area greater than 130 mm shall be enclosed 'in a conduit and used for alternating

25.1.10 Erection and earthing of conduit - The conduit of each circuit or section shall be completed before conductors

are drawn in. The entire system of conduit and permanently connected to earth conforming to the requirements

specified under pipe in a workman like manner for a perfect continuity between each wire and conduit. Gas or

water pipe~ shall not be used as earth medium. If conduit pipes are liable to mechanical damage, they shall be

adequitably protected.

25.2 Recessed Conduit wiring system with Rigid Steel conduits - Recessed conduit wiring system shall comply

with all the requirements for surface conduit wiring system specified in 6.5.1.1 to 6.5.1.1 0 and in addition,

conform to the requirements specified in 6.5.2.1 to 6.5.2.4.

25.2.1 Making of chase - The chase in the wall snail be neatly made and be of ample dimensions to permit the conduit

to be fixed in the manner desired. In the case of buildings under construction, chases shall be provided in the

wall, ceiling etc., at the time of their construction and shall be filled up neatly after erection of conduit and

brought to the original finish of the wall.

25.2.2 Fixing of conduit in chase. The conduit pipe shall be fixed by means of staples or by means of saddles not

more than 6G cm. apart. Fixing of standard bends or elbows shall be avoided as far as practicable and all

curves maintained by bending the conduit pipe itself with a Ionge radius which will permit easy drawing-in of

conductors. All threaded joints of rigid steel conduit shall be treated with some approved preservative compound

to secure protection against rust.

25.2.3 Inspection boxes – Suitable inspection boxes shall be provided to permit periodical inspection and to facilitate

removal of wires, if necessary. These shall be mounted flush with the wall Suitable ventilating holes shall be

provided in the inspection box covers.

25.2.4 Type of accessories to be used - All outlets such as switches and wall sockets, may be either or flush

mounting type or surface mounting type.

(a) Flush mounting type - All flush mounting outlets shall. be of cast iron mild steel boxes with a cover of

approved insulating material or shall be a box made of a suitable insulating material. The switches and

other outlets shall be mounted on such boxes as would be approved. The metal box shall be efficiently

earthed with conduit by an approved means of earth attachment.

(b) Surface mounting type - If surface mounting type outlet box is specified, it shall be of any approved

insulating material and outlet mounted in an approved manner.

25.25 When crossing through expansion joints in buildings, the conduit sections across the joint may be through

flexible conduits of the same size as the rigid conduit.

25.3 Conduit Wiring System with Rigid Non-Metallic Conduits:

Rigid Non-Metallic conduits are used for surface. recessed and concealed conduit wiring.

25.3.1 Type and size - All non-metallic conduits used shall conform to IS : 2509-1963 and shall be used with the

corresponding accessories (See IS : 3419~ 1965) specification for Fittings for Rigid Non-Metallic. Conduits).

25.3.2 Bunching off cables - Conductors of AC supply and DC supply shall be bunched in separate conduits. The

number of insulated cables that may be drawn into the conduits are given in Table III. In this table space factor

does not exceed 40 percent.

TABLE-III MAXIMUM PERMISSIBLE NUMBER OF 250 VOLTS GRADE SINGLE- CORE CABLE THAT MAY BE

DRAWN INTO RIGID NON-METALLIC CONDUITS

Size of conduit (mm)

Nominal No. Diameter in 16 20 25 32 40

Crossectional area mm of wires (No. of cable Max)

* For Cu. Conductors only.

+For AI. Conductors only.

25.3.3 Conduit joints - shall be joined by means of screwed or plain couplers depending on wheather the conduits are

screwed or plain. Where there are long runs of straight conduit. Inspection type couplers shall be provided at

intervals. For conduit fittings and accessories reference may be made to IS : 3419-1965.

25.3.4 Fixing of conduits -The provision of 25.1.6 shall apply except that the spacing between saddles or supports is

recommended to be 60 cms for rigid non-metallic. conduits.

25.3.5 Bends in conduit - Wherever necessary, bends or diversions may be achieved by bending the conduits (See

6.5.3.9) or by employing normal bends, inspection bends, inspection boxes, elbows or similar fittings.

25.3.6 Conduit fittings shall be avoided, as far as possible on outdoor system.

25.3.7 Outlets - All the outlets for fittings, switches, etc.. shall be boxes of substantial construction. In order to minise

condensation or sweating inside the conduit, all outlets of conduit system shall be properly drained and

ventilated, but in such a manner as to prevent the entry of insects: etc. as far as possible.

25.3.8 For use with recessed conduit wiring system the provisions of 6.5.2.1 to 6.5.2.4 shall apply.

25.3.9 Heat may be used to soften conduit for bending and forming joints in case of plaint conduits. As the material

soften when heated, fitting of conduit in close proximity to hot surfaces should be avoided. Caution should be

exercised in the use of the conduit in locations where the ambient temperature is 50°C or above Use of such

conduits in place where ambient temperature is 60°C or above is prohibited.

PVC INSULATED AND P. V.C. SHEATHED OR T.R.S. WIRING SYSTEM

This system of wiring, is suitable for I()w pressure installation, and shall not be used in places exposed to sun

and rain nor in damp places, provided they are sheathed in the special approved protective covering and well

protected to withstand dampness.

26.1 Attachment to walls and ceiling :

26.1.1 All cables on brick walls, stone or plastered walls and ceiling shall be run on well seasoned, perfectly straight

and well seasoned, perfectly straight and well varnished on four sides, teak wood or any approved hardwood

battens not less than 10 mm finished thick, width of which shall be such as to suit total width of cables laid on

the batten, prior to election, these shall be painted with one coat of varnish or approved paint of colour to match

with surrounding. These battens shall be secured to wall and ceilings by flat head wood screws to raws plug or

Phil plug at an interval not exceeding 75 cm. Wood plug can be used only with special approval of the Engineer-

in-charge. The flat head wood screws shall be counter within wood batten and smoothed down with file.

26.1.2 Where wiring is to be carried out along the face of the rolled steel joints a wooden batten of adequate width shall

first be laid on the same and dipped to it as inconspicuously as possible. The wiring should then be fixed to this

backing shall be suitably bushed to prevent the abrasion of the cables.

26.1.3 Attachment to false ceiling :In no case, the open wiring shall be run above the false ceiling without the approval

of Engineer-in-charge.

26.20 Link dips: Only aluminium alloy clips/joint clips shall be used. The thickness shall be 0.32 mm (30 SWG) for

lengths of 25 mm to 40 mm and 40 mm (28 SWG) for lengths o! 50 mm to 80 mm. The width shall not be less

than 8 mm in all these cases. Link clips/joint clips shall be so arranged that one single clip shall not hold more

than two core or three single core TRS of PVC insulated and PVC sheathed up to 2.5 sq. mm above while a

single clip shall hold a single twin core or two single core cables. The clips shall be fixed on varnished wood

batten switch iron pins and space at interval of 15 cm both in the case of horizontal and vertical runs.

26.3.0 Bends in wiring :The wiring shall not in circumstances be bent so as to form an abrupt right angle but must be

rounded off at the corners to a radius not less than six times the overall diameter of the cable.

26.4.0 Protection of wiring from Mechanical Damage:

26.4.1 In cases where there are chances of any damage to wiring, such wiring shall be drawn complying with all the

requirements of conduit -wiring system.

26.4.2 Such protective covering shall in all cases be fitted on all down drops within 1.5 m from the floor, or from floor

level up to the switch board whichever is less.

26.5.0 Passing through floors: All cables taken through floor shall be enclosed in heavy gauge steel conduit extending

1.5 to above the floor or up to the switch board whichever is less and flush with the ceiling below or by means of

any approved type of metallic covering. The ends of all conduits or pipes shall be neatly bushed with porcelain

wood or other approved material. The conduit pipes, shall be security earthed.

26.6.0 Passing>through walls: When conductors pass through walls, anyone of the following methods shall be

employed. Care should be taken to see that wires pass very freely through protective pipe or box and that wires

through in a straight line without any twist or cross in wires on either ends of such holes.

(a) A box of teak wood or approved hard wood extending through the hole thickness of the wall

shall be buried in the wall and casings or conductors and casing or conductors shall be

carried so as to allow 1 .3 cm air space on the three sides of the casing or conductor.

(b) The conductors shall be carried in an approved heavy gauge solid drawn or lap weld conduit

or in a porcelain tube of such a size. that it permits easy drawing in, the ends of conduit shall

be neatly bushed with porcelain, wood or other approved material,

26.6.1 Where a wall tube passes outside a building so as to be exposed to weather, the outer end shall be

mounted and turned downwards and properly bushed on the open en<!. The conduit shall be neatly

arranged so that the cables enter them without bending.

26.7.0 Buried cables: The TRS or PVC sheathed cable shall not normally be buried directly in plaster.

Where so specified in the special specification they may be taken in teak wood channeling of ample

capacity or conduit pipe buried in the wall.

26.8.0 Stripping of outer covering. While cutting and stripping of the outer covering of the cable care shall

be taken that the sharp edge of the cutting instrument does not touch the inner insulation of the

conductors. The protective outer covering of the cables shall be stripped off near connecting terminal

and this protective covering shall be maintained up to the close proximity of connecting terminals as

far as practicable. Care shall be taken to avoid hammering on link clips with any metal instrument

after the cables are laid. Where junction boxes are provided they shall be made moisture proof with a

plastic compound.

27.0 PAINTING WORK IN GENERAL:

27.1 Paints: paints, oils varnishes, etc, of approved make in original to the satisfaction of the Engineer-in-

charge shall only be used.

27.2 Preparation of surface: The surface shall be thoroughly cleaned and dusted before painting is

started. The proposed surface shall be inspected by Engineer-in-charge or his authorised agent and

shall have received the approval before painting is commenced.

27.3 Application : Paint shall be applied with brush. The paint shall be spread as smooth & even as

possible. Particular care shall be paid to rewets, nuts, bolts and cover lapping. Before drawing cut, it

shall be continuously stirred in the smaller containers with a smooth stick while it is being applied.

Each coat shall be allowed to dry out sufficiently before a subsequent coat is applied.

27.4 Scope: Painting on old surface in indoor situations will not include primer coat except where

specially mentioned in the schedule of work or special specification. However, where rust has

formed on iron and steel surfaces the spots will be painted with one anti-rust primer coat.

27.5 Precautions : All furniture fixtures. glazing floors, etc, shall be protected by covering. All stains,

smears, oplashings, dropping of every kind shall be removed. While painting of wiring etc. it shall be

ensured that painting of wall ceiling etc. is not spoiled in any way.

27.6 Painting of conduit and accessories: After installation surface of conduit pipes, fittings switch and

regulator boxes, etc. shall be painted with two coats of approved enamel paint or aluminium paint as

required to match the finish of surrounding wall, trusser, etc.

The clip for batten wiring shall be of Aluminium conforming to I.S. specification No. 2415-1975.

Important Clauses of Indian Electricity Rules, 1956. Following clauses of

Indian Electricity Rules, 1956 shall in particular be

taken care of in the execution of electrical works

Clause No. Subject

3. Authorisation :

29. Construction, installation, protection, operation and maintenance of electric supply lines and apparatues.

31. Cut-out on consumer's premises.

32. Identification of earthed and earthed neutral conductors and position of switches and cutous therein.

33. Earthed terminal on consumer's premises.

34. Handling of electric supply lines and appartus.

41. Distinction of circuits of different voltages.

42. Accidental charge.

43. Provisions applicable to protective equipment.

44. Instructions for restoration of persons suffering from electric shock.

45. Precautions to be adopted by consumers, owners, electrical contractors, Electrical workmen and suppliers.

46. Periodical inspection and testing of consumer's installation.

48. precautions against leakage before connection.

50. Supply to consumers.

51. Provisions applicable to medium, high voltage installations. Point of commencement of supply.

58. Point of commencement of supply.

59. Precautions against failure of supply; Notice of failures.

61. Connection with earth, (low and Medium Voltage system.

64. Use of energy at high and extra-high voltage system.

67. Connection with earth. (High & Extra-high voltage system.

68. General conditions as to transformation and control of energy.

All clauses under Chapter VIII on Overhead Lines.

137. Mode of entry.

138. Penalty for breaking seal.

139. Penalty for breach of rule-45.

140. Penalty for breach of rule-82.

141. Penalty for breach of rules.

From of Completion Certificate

I/We certify that the installation detailed below has been installed by me/us and tested and that to the best of

my/our knowledge and belief, it complies with Indian Electricity Rules, 1956, as well as the C.P.W.D. General Specifica-

tion for Electrical Works,

Electrical Installation at Voltage and system of supply

(1) Particulars of works :

(a) Internal Electrical Installation No. Total Load Type of system

(i) Light point

(iii) Plug point

(a) 3 pin 5 Amp.

(b) 3 pin 15 Amp. Others :

(a) Motars : (i) HP/KW

(c) Other Plants:

(d) If the work involves installation of over head line/or under ground cable:

(a) (i) Type & Description of overhead line.

(ii) Total length & No.-of spans.

(iii) No. of street light & its description

(b) (i) Total length of under ground cable & its size.

(ii) No. of joint.

St through jont.:

(i) Description of earthing elecrode :

(ii) No. of earth eletrodes :

(iii) Size of main earth lead:

3) Test Results:

(a) Insulation Resistance:

(i) Insulation resistance of the whole system

of conductors to earth. Megohms

(ii) Insulation resistance between the

phase conductors and neutral. Megohms

Between phase R and neutral Megohoms

Between phase Y and neutral Megohoms

Between phase B and neutral Megohoms

(iii) Insulation resistance between the phase conductors in case of polyphase supply.

Between phase R & phase Y Megohoms

Between phase Y & phase B Megohoms

Between phase B & phase R Megohoms

(b) Polarity Test:

Polarity of non linked single pole branch switches.

(c) Earth continuity Test:

Maximum resistance-between any point in the earth continuity conductor including metal conduits & main

d) Earth Electrod Resistance:

Resistance of each electrode.

e) Lighting Protective System :

Resistance of the whole of lighting-protective system to earth before any bonding is effected with electrode and

metal in/on the structure.

Signature of Supervisor Signature of Contractor

Name & Address Name & Address

All Specification, standard. publication etc. specified mean the latest standards. publication etc.

pertaining to Electrical Installation and should conform to the following wherever applicable.

1) Indian Electricity Act, 1910 with its amendments.

2) Indian Electricity Rules, 1956 and its amendments.

3) Indian Electricity supply Act,

4) Regulation for Electrical Equipment in building by I.E.F. Landon.

5) The Factory Act. 1948 and its amendments.

6) I.S.-732-1982 Part-I, II & III code of practice for Electrical wiring and fittings in buildings for low

and medium voltages.

7) I.S. 4064-1967 H.D. Air break switches and fuses for Voltages not exceeding 1100 volts.

8) I.S. 3043 - Earthing code of practice for

9) I.S. - 1554 Part-I - 1970 PVC insulated (Heavy duty) Electrical Cables for working voltages upto

and including 110 volts.

10) I.S. : 694 - 1964 Part- II - PVC insulated cable with Alluminium conduits (revised) for voltages

upto 110 volts.

11) I.S: : 5908-1970 - Electrical installations in buildings. method of measurements of.

12) I.S.: 4237-1967 - General requirement for switchgear and control gear for voltage not

exceeding 1000 volts.

13) IS: 1653-1964 - Rigid steel conduits for electrical wiring (revised)

14) IS : 2509-1973 - Rigid steel conduits for electrical installation. (First revision).

15) IS: 1258-1967 - Beyonet lampholders (First revision).

16) IS: 418-1957 - Tungston-Filament General service electric lamps (Third revision).

17) IS: 374-1966 - Fans and Regulators. ceiling type, electric (second revision).

18) IS : 2667-1964 - Fittings. for rigid steel conduits for electrical wiring.

19) IS: 3419-1976 - Fitting for rigid non-metallic conduits (First revision).

20) National Electric Code,

Abstract of the Wiring Rules of the Institution of

Electrical Engineer

(referred to in the specification)

DEFINITIONS (See Clause 2 of the Specification)

All electrical system in which all the conductor and appartus are electrically connected to a common source of

1) Earthed: Effectually connected t9 the general mass of the earth. Solidly earthed means earthed without the

intervention of a fuse, switch, circuit -breaker, resistor reactor or solenoid.

2) Uninsulated Conductor: A conductor without provision, by the interposition of a dielectric or otherwise, for its

insulation from earth.

3) Bare: Not covered with insulating material.

4) Dielectric : any material which offers high resistance to the passage of an electric current.

5) Bunch Conductor: When more than one conductor is contained within a single duct or groove or when they

are run enclosed and not spaced apart from each other. .

6) Points: In wiring as per IS : 5908-1970-Method of measurements of electrical installation in buildings

7) Switch board: An assemblage pf switchgear with or without instruments, but the term does not apply to a group

of local switches in a final sub-circuit where each switch has its own insulating base.

Note: In the electricity (Factories Act) special regulations,. 1908 and 1944 the term "Switchborad" includes

"Distribution board" .

8) Single pole switch: A switch suitable for closing and or opening a circuit on one phase or pole only.

9) Linked switches: A switch the blades of which are so linked mechanically as to make or break all poles

simultaneously or in a definite sequence.

10) Fuse Switch: A switch the moving part of which carries one or more fuses.

11) Three Wire System:.

a) Outer Conductor: Those between which there is the greatest difference of potential. This use of the word outer must not be

confused with the use of the work when applied to the external conductor of a concentric main.

b) Neutral Conductors: The term includes the natural conductor of a 3 phase 4 wire system, the conductor of a

single phase or d.c. installation which is earthed by the supply undertaking (or .otherwise at the source of the

supply) and the middle wire or common return conductor of a 3 wire d.c. or single phase a.c. system.

12) Semi enclosed machine: One in which the ventilating openings in the frame are covered with

a) Grids expanded metal or wire gauge, with openings of less than 1/4 inch so as t6 obstruct free ventilation.

b) Wire gauge, in which the openings are less than 1/41 inch but not Jess than 3/32 inch (diameter or width) :

c) Screens with smaller openings than the above.

13) Totally - enclosed Machine:

One in which the enclosing case and bearings are dust proof and which does not allow circulation of air

between the inside and outside of the case.

14) Pipe Ventilated Machine: An enclosed machine in which the frame is so. arranged that the ventilating air may

be conveyed to. it through a pipe attached to. the frame, the ventilation Opening maintained by the fanning

action producted by the machine - itself.

15) Farced draught machine: An enclosed machine in which the ventilating air supply is maintained by an

independent fan external to. the machine itself.

16) Protected Machine: One having end shield bearings and in which there is free access to. the interior without

opening doors removing cavers.

SWITCHES. AND CIRCUIT BREAKERS

(See clause II of Specifications)

17) Switches and Circuit Breakers.:

Switches and circuit breakers (rules 2b. 36 and 37) whether' fixed separately or combined with lamps, holders

or fittings, must comply with the following requirements:

(a) Overt heading must not take place at the paint of contact or elsewhere, when the full current flows

(b) They must be so. constructed or arranged that the contracts cannot accidentally close when left open.

(c) The basis must be of incombustible, non-conducting and moisture proof material.

(d) Circuit breaker as must be so. arranged and placed that no combustible material is endangered by

(e) Unless placed in an engine roam or in a compartment especially arranged for the purpose,

they must their live parts covered. The covers must be of incombustible material and must

be either non-conducting or of rigid metal and clear of all internal mechanism. For mare than

6 amperes, at pressures exceeding 125 Valts metal' cavers must be lined with insulating

(f) In positions where they are liable to. injury or come into. contract with goads, they must be further

protected by an open fronted box or other suitable guard.

(g) Handles must be insulated and so arranged that the hand cannot touch live metal, or be injured

through and adjacent fuse blowing.

(h) Switches having a handle projecting through an open slat in the cover, must not be used.

Signature of Contractor/s Executive Engineer

GENERAL REQUIREMENTS

1.1 Scope of works :

The work covered by electrical specification consists supplying and installing, electrical wiring system complete

in 'strict accordance with this specification and the applicable drawing and subject to. the terms and conditions

pf the contract. It includes. .

(a) Conduit a wiring system far fans, lighting paints bells, clacks sockets, etc. including fixing of lighting fixtures and

fans etc. and miscellaneous paints.

(b) Conduit and wiring system' far exhaust fans, power sockets.

(c) Panel boards, distribution boards. switch fuse units.

(d) Complete power and lighting cable systems. Grounding system.

(e) Grounding system.

(f) Conduits system.

(g) Street lighting system.

(h) Other miscellaneous electrical work.

1.2 Completeness of Contract:

Any work fittings accessories or apparatus which may not have been specifically mentioned in the specification

but which are necessary in the equipment for efficient working of the plant should be deemed to be included in

the contract and should be executed and provided by the contractors. All plant and apparatus should be

complete in all the details, where such details, are mentioned in the specifications or not.

Three prints and one permanent negative of each' of the finally approved drawings incorporating all the

modifications proposed by the Department should be submitted. No modifications should be made in a drawing

already approved by the Engineer-in-charge without his prior consent.

Approval of the contractor's drawing will not relieve the contractor of any part of his obligation to meet all the

requirements of the contract.

1.3 Guarantee :

The performance of all the equipments and the installations should be guaranteed at least for a minimum period

of one year from the date of taking over the installation by the Department'. All equipments must comply with the

relevant IS-BS specifications.

1.4 Interchangeability:

All corresponding parts of similar plant and equipment should be? interchangeable in every way.

All special tools required for dismantling and assembly of the equipment covered by the contract shall be

supplied as obligation under the contract.

A list of items to be supplied by the Contractor should be submitted along with the tender.

Specifications for Electrical Installation in Buildings

1.1 These specifications relate to the electrical installations in 'the buildings of P.W.D. Electrical. The specifications

cover general requirements to be fulfilled. These general specifications are supplemented by the specifications

for the particular buildings separately attached.

1.2 These specifications are governed by the General conditions of the contract attached hereto.

1.3 APPLICABLE RULES AND REGULATIONS:

1.3.1 Installation shall be carried out in conformity with the regulations for electrical equipments of buildings,

published by the Institute of Electrical Engineers London (14th Edition 1966 and as amended upto date) herein

after referred to as the I.E.E. wiring regulations. Where these specifications. or the special specifications for the

particular building attached hereto are at variance with the I.E.E. regulations these specifications or special

specifications ~s the case may be, shall be followed. The installation shall also comply with the requirements of

the Indian Electricity Act, 1910 as amended up to date and rules issued hereunder and also the regulations for

the Electrical Association of India. Where not specified otherwise, the installation should generally follow the

Indian standard codes of practice and in their absence the relevant British Standard of practices. All the

materials shall comply with the relevant Indian Standard of British Standard specifications.

1.4 DEFINITIONS:

1.4.1 The definitions of terms in the I.E.E. Regulations shall apply in general.

1.5.1 The preliminary drawings only indicate the general scheme of requirement. The exact position of all points,

control switch boxes, runs of wiring and/or conduits joint boxes, inspection boxes, mains, and sub-distribution

boards, mains etc. shall be got approved by the Engineer-in-charge. All circuits shall be clearly numbered in

wiring diagrams and building plans. The detailed design of a switch-board, special fixture or any other part of

the electrical installation as may be called for by the engineer-in-charge shall also be supplied by the Contractor

and should be got approved by the Engineer-in-charge. Three sets of completion drawings am wiring diagrams

showing the installations as executed shall be supplied by the contractor alongwith the completion certificate.

All materials shall be new and of the best quality conforming to the relevant I.S.B.S. specifications. They must

be the products of reliable manufacturers of many years or standings. All like parts of materials shall be

interchangeable. In case pf equipments such as circuit breakers, switch fuses etc. a descriptive and illustrated

literature shall accompany the tender. The names of manufacturers of various materials shall be furnished in

proforma in Appendix. Samples of materials wherever required should be approved by the Engineer-in charge

before use in the installation. One set of such approved samples shall be deposited with the Engineer-in-

charge. All materials shall be rust-proof or rendered rust proof by application of suitable paints. The supply of all

equipments, switchgears etc. 'shall be complete with accessories. fittings and mountings as may be required for

their proper performance, and as specified in the relevant IS-BS Code of Practice and standards.

1.7 WORKMANSHIP:

1.7.1 Good workmanship and neat finished appearance are the prerequisites for complying with the clauses of these

specifications. With a view' to ensure fine workmanship the tenderers shall employ licensed 'wiremen, with an

experience of not less than 5 years in the type of work’ they are engaged. The work should be done under

supervisions of licensed Electrical Supervisors with good educational qualifications and considerable

1.7.2 Tenderers shall furnish the names of Supervisor and their wiremen who will be engaged in this work with details

of their experience.

1.8 CO-OPERATIVE WITH CIVIL AND OTHER WORKS CONTRACTORS:

1.8.1 The tenderer, after the award of the contract. shall co-operate with the civil and other contractors and shall co-

ordinate his work with the work of other contractors with the least amount of dislocation and interference to the

other works. Tenderers shall go through the drawings carefully and shall furnish the Engineer-in-charge with all

the details of openings in the walls etc. they may be required for concealing any of the electrical equipments or

accessories. Where the contractor fails to furnish such information as may be required for the purpose of

concealing the equipments etc. they shall be made at his (Contractor) cost and expense. Any alteration to parts

of the building shall be carried out with prior permission of the competent authority. All chaises of the structural

work shall be made good at the contractor's expense and brought to the original shape finish and concur.

The electrical contractor shall be completely responsible fo the testing and commissioning of those installations

covered by these specifications in compliance with the standard procedure, in/obtaining permission of the

Government Electrical Inspector. Any modification which is demanded by Government Electrical Inspector shall

have to be carried out within the scope of the contract. The contractor shall submit four copies of drawings of

installations as per regulations for shall be provided by the contractor for carrying out the installation work. All

tests shall be carried out in the presence of the Engineer-in-charge or his authorised representative and his

approval obtained for the test results.

1.10 . COMPLETION CERTIFICATE AND MAINTENANCE GUARANTEE:

1.10. 1 After the completion of the installation and testing, the contractor should furnish a certificate in the proforma In

Appendix-III, at the time of taking over the installation by the Department. The installation shall be guaranted for

period of 12 months from the date of taking over by the Department. During the period of guarantee all defects

in material or in workmanship shall be rectified or replaced free of cost to the Department.

1.11 TENDERER’S ABILITY:

1.11.1 In order to enable the Department to asses the ability of the tenderer to execute the work. the tenderer shall

furnish evidence of his experience and capacity td carry out the work of the magnitude and nature.

The rates of items shall include all taxes, transport, loading and unloading charge and all such charges that may

be required to be incurred for the supply and installation of the materials at site. The rates shall be firm and

variations in the market are not entertained. Break up figures as required in the schedule of work shall also be

furnished. As far as possible indigenous materials only shall be included for supply. Where it is unavoidable,

imported items may be included and tenderer should clearly indicate materials, quantity, rate and amount of

1.13 STORAGE SPACE:

No covered storage space will be provided by the Department. The contractor has to make his own

arrangement. However, the Department may give an open space near the place of execution where the

contractor can build his own stores for executing the work.

1.14 DEPARTURE FROM SPECIFICATIONS:

The tenderer should clearly indicate departure, if any, from the specifications with reasons for the same.

1.15 EXTRA ITEMS:

Rates for extra items shall generally be derived from the rates already available in the schedule. Where it is not

possible, the rates shall be mutually agreed upon and the contractor shall furnish a detailed analysis of the rates

claimed by him.

2. TECHNICAL SPECIFICATION:

2.1 Supply System:

The wiring installation shall be suitable for 3 phase 4 wire. 400-440 V 50 cycles system of supply. Colour code

of different phase shall be followed as per standard.

2.2 Wiring for Lights and Fans:

2.2.1 Looping system of wiring shall be adopted. No joints shall be made at intermediate runs of cables and where

they are unavoidable. such joints shall be through approved mechanical connections.

2.2.2 Point wiring:

Point wiring shall consist of the branch wiring from the switch board together with the controlling switch or push as far

as and including the ceiling rose or any other approved connector or socket. outlets. In case of more than one light

being controlled by one switch, the wiring upto the ceiling rose of the first light including the switch shall be considered

as a 'Primary point. Loop wiring from light shall be considered as a 'Secondary' point and rates shall be quoted

separately, including final connections to fixtures land plugs.

No conductor for final sub circuit wiring for light and socket outlets. shall have across-section less than that of

sq. m (aluminium).

No final sub-circuit radiating from the fuse board of a sub- distribution board and wires with 25 sq. m. (AI.) cable shall

carry more than 10 lights, fans or socket outlets or ai connected load of 800 watts whichever is grater. The {allowing

wattages may be assumed for estimating the load on each sub-circuit unless otherwise known jar specified.

Incandescent Lampts 1 00 watts

Ceilling fans 60 watts

5-A Socket Outlets (lighting) 100 watts

4. ft. fluorescent tube. 50 watts

5 ft. fluorescent tubes. 100 watts

In each sub-distribution board at least one way preferably two ways shall be left spare for future requirement. A wiring

diagram giving the details of the exact utilization of the ways shall be prepared and fixed in the sub distribution board

itself or any other easily accessible place. The ways of sub-distribution boards shall be accordingly numbered.

2.2.5 Local Control Switches (General) :

Local control switches for circuit carrying not less than 5-5 shall be piano type and shall conform to relevant I.S.

Standards. The switch shall be 'ON' when the knob is in the down position. All local control switches shall be

connected in the phase or live conductor only and not in the neutral conductor, switches shall be fixed in iron clad box

and shall be so placed that the centre of the switch box is 1.3 mtr. from the finished floor level unless otherwise stated.

All switch boxes shall be provided with 1/8" thick Perspex cover fixed to the switch box with chromium plated counter

sunk screws (brass).

2.2.5A Switches (Two way) :

(a) Two way switches shall be piano type single pole, (double throw, 250V, suitable. for flush mounting and of 5A

capacity as per the drawings. All switches shall be recessed in an embedded metal box.

(b) Each box shall have suitable outlet for fixing conducts directly.

(c) Each box shall have Perspex cover painted inside with the wall colour, if required.

(d) Each switch shall be suitable for the position in a corridor stairway wiring.

2.2.5B Switch Boxes (General):

Electrical circuits shall be written suitably on the cover of all switch boxes. as approved by the Engineer-in-charge

(Elect) whenever different phase are terminated in a switch box bakelite partition shall be provided. Each case shall be

provided with a G.I. Earth stud nut and washers for earth connectors.

2.2.6 Ceiling Rose:

Ceiling rose shall be used on circuits having a voltage normally exceeding 200V. Only one flexible cord shall be

attached to a ceiling rose. Only 3-pin 5A socket outlet shall be provided in lighting circuits. All socket outlets shall be

provided with a control switch and they shall be mounted in switch boxes in an approved manner.

2.2.7 Fittings:

These shall be of approved type as specified in the tender schedule. The sub circuits leads should terminate in a .

ceiling rose or conductor in the fitting and internal connection made there from. Wherever these fitting are suspended

they shall be done so through the conduits and ball and socket joints. All fittings shall be grounded by a G.I. conductor

not less than 16 S.W.G.

2.2.8 Flexible wiring:

Flexible cords of not less than 23/0076 size shall be used. The weight of suspension shall be governed by I.EE.

2.2.9 Ceiling Fans:

All ceiling fans shall be wired to ceiling rose and suspended from a hook shackle or clamp and insulated from the

same. All joints in the suspension road shall be screwed and secured. by means of split pins. The fan clamps supplied

by the Contractor shall be suitable for the ceiling or proof member as the case may be. For concrete roofs,

fan hooks shall be buried in concrete during construction in an approved manner and securely bound to the

2.2.10 Conduits and Earthing:

All conduits feeding lighting and fan circuits shall be provided with earth continuity G.I. conductor as specified for

power wiring. All conduits shall be as specified for power wiring.

2.3.1 Point wiring:

Point wiring for power shall be as defined under section 2.2.2 and shall include the switches and sockets.

All distribution board for power wiring shall be not less than 15A per way. Loading per way shall not exceed'

normally 100 watts. The following loads may be assumed if exact figures are not known.

3-Pin 15A Outlets 1,000 Watts

3-Pin 5A Outlets 100 Watts

2.3.3 Wiring for Motors:

2.3.3.1. Final sub-circuits loop in motors shall be connected to separate ways of the Distribution board even if the

current in the sub-circuit is less then 15A. No looping is permissible.

2.3.3.2 All wiring shall be carried in H.G. conduit as specified in I.S. specification for gauge for different sizes of

When the motor is resiliently mounted flexible conduit with approved adopters shall be used for the last few feet.

Where cables are used sufficient loop shall be left.

2.3.3.3 All switch fuse units controlling circuits feeding motor shall be provided with H.R.C. fuses or as specified.

2.3.3.4 The frame of every motor and its association control gear shall be earthed by two separate and distinct

connections to earth connector shall be capable of carrying 3 times the rating of fuse or 1.1/2 time the setting

or the circuit breakers but in no case less than No.8 S.W.G. or 7064" or equivalent cross section of copper.

Where practicable, the earth connections shall be visible for periodical inspection. Gas or water pipes shall not

be used for earth connections.

2.3.3.5 Socket Outlets and Control Switches 5A and 15A :

All socket outlets shall be of 3 pin type, the third pin being connected to the earth stud of nearest distribution

board by separate earthing wire. The socket shall conform to I.S. : 1293/1938, single pole, piano type. Each

socket outlets shall be provided with a control switch of appropriate rating and as specified. The switch and

socket shall be mounted inside the iron clad box provided with 1/8" Perspex cover as directed by the

Engineer-in-charge or as specified in schedule .of quantities. Inside switch box ample space shall be available

around switches for connecting wires to switches. All socket outlets for power shall be mounted at the skirting

level unless otherwise specified or as directed by the Engineer-in-charge.

The three phase plug receptanles shall have their earth terminals connected by independent earth wires to

ring main earth strips on the building. In buildings where explosion proof fixtures are installed single phase

plug receptanles as well as light points shall be connected to ring main ground bus installed in the building by

separate earth wires of approved size."

Socket outlet shall have some provision not to receive the matching plug unless the grounding pin is in correct

position. The grounding pin of the plug shall make the contract first and break the contract last at the time of .

inserting or removing the plug respectively.

The grounding terminal shall be connected to the enclosed metal body by providing G.I. stud. nut washers

welded to the box.

Each unit shall be suitable for flush mounting as required and indicated in the applicable drawings.

Combination unit of socket outlet and switch shall be complete with necessary internal wiring. The witch/socket

shall be mounted on M.S. bracket enclosed in a box.

2.4 Conduit Wiring:

2.4.1 Where conduit wiring is adopted the type and size of the conduit shall be as indicated in the drawing. The

minimum of the conduit shall be 19 mm.

2.4.2 The contractor shall thoroughly study the' structural arrangements of the buildings and wherever, necessary

shall in consultation with Department's representatives at site, make suitable adjustments in the cable routings,

earthing arrangements, and location boxes, fitting etc. with a view to avoid interference with any part of the

building, structure, equipment or any other work in the building or to effect any improvement in the arrangement.

2.4.3 Protection of conduit against rust:

Conduit shall be given two coats of oxide paint before they are placed in position. All exposed conduit shall be

planted after installation with the colour as approved by the Engineer-in- charge. This do not apply to galvanised

2.4.3.A Protection against insects and damp:

In order to minimise cocensation or sweating inside the conduit, system shall be properly drained any ventilated in

such a manner as to prevent the entry of insects.

2.4.4 Conduit shall first be installed as a complete system without cables and shall be continuous from outlet to outlet

from fitting to fitting and mechanically and electrically connected to all boxes and fittings.

2.5 SPECIFICATION FOR POWER CONTROL AND TELEPHONE CABLES :

i. The specifications cover the supply and installation of meduim voltage power and control cables either

in ground or trench depending on the conditions at site including accessories for the same. The work in

general, consists of supplying, laying, jointing terminating and connecting all. 1.1. KV APLSTS PVC

power and control cables.

ii. The contractor shall supply all accessories including jointing and terminating materials, compound,

tapes supporting materials, cleats cables lugs, concrete stabs, bricks sand, cable markers etc, as

required to make the installation work including digging and back filling of the trenches as required.

II. SPECIFICATION:

i. All power cables to be supplied mentioned as 'APLSTS' in the Schedule should be mass impregnated,

non draining, paper insulated lead sheathed. double steel tape armoured and must comply with the

latest ISI BS specifications.

ii. All cabling materials such as cable compound, cable lugs, tapes shall be of approved quality

acceptable to the type recommended by the manufacturer of the cable for which it is used and

approved by the Department.

iii. Installation of all equipment shall also conform to the applicable. Codes and practice as per the IS and

shall be executed to comply with the lates Indian Electricity rules as regards the safely. earthing of

equipments and other essential provisions specified therein.

iv. Only approved make of cable shall be used. ICC and CCI will be preferred.

v. The cables shall generally be laid as per is Code of practice.

III. GENERAL RULES CABLE LAYING:

i. Installation shall be carried out in a neat. workmen like manner by skilled experienced and competent

workmen in accordance with the standard practices.

ii. Cables shall be laid preferably in one piece length to avoid joins. If straight joints are found necessary.

these can be introduced with prior approval of the Engineer-in-charge. The cost of the straight joint

however. shall not be borne by the Department. But in no case joint shall be within the conduit G.I.

iii. Proper care should be exercised in handling the cable to avoid formation of kind etc. and should it

become necessary a cable be bent to a radius not less than 20 times the overall diameter of the cable.

iv. Method of installation, routing of cable etc. shall in every case be subject to the Department's approval

and the contractor shall modify and or certify at no extra cost to the Department any portions of the

installation which do not meet with the Department's approval. All damages to the civil and other works

on this account shall be made good by the contractor at no extra cost to the Department.

The electrical contractor while notifying the building contractor for such work shall furnish the proper

drawings, fully explaining the work involved or indicate at site actual work to be carried out as may be

required by the building contractor. The electrical .of any such work as soon as the, electrical work with

respect to the same has been completed.

v. Where cables pass through hume pipes. contractor shall fix hard wood bushed round the cables at the

ends of hume pipes. Where the cables pass through the floors or chambers and in such other

situations as the Engineer shall require. the contractor shall seal cable holes in a manner approved by

Engineer-in- charge. Where cable pass through roads nallahs, etc. cables must be protected by Class

'A' Hume pipe of diameter not less than 6" (15cms.)

vi. The cable route shall be the shortest and these shall be minimum interference with built up areas,

vii. Care shall be exercised for providing suitable props for supporting other service lines on earth at the

time of excavation. Where cutting of a lawn become inevitable it should be with the approval of the

Engineer-in-charge.

viii. Excavation of the trenches shall be executed with vertical sides and the trenches shall be kept as

straight as possible. The exact location of each trench shall be served by the Engineer- in-charge. On

the site when the contract is in a position to commence each portion of the work.

The trench shall be not less than 1/2 meter wide and 90 cms deep. If more. cables are to be laid. the

width should be suitably increased.

ix. After the cables are laid. the trench shall. be filed in layers, the earth in each layer being well rammed

by spraying water and consolidated and sufficient allowance made for settlement. The extra earth

over the trench should be removed from the place of trench to a place as decided by the Engineer- in-

charge at site.

x. Ends of cables shall be properly sealed to prevent entry of moisture prior to installation.

xi. Where it is as specified as 1/2 core cables the 1/2 core shall be a neutral conductor having reduced section.

xii. For all multicore cables each core and tails shall be brought out, marked and or coloured in on

approved manner.

xiii. Cables termination shall be done with suitable compression brass qlands in the case of PVC cables

and cast iron triturating boxes in the case of APLSTS cables. The armour should be connected to the,

right main earth in building with duplicate earth wires as per the relevant lS/BS specification.

The core insulation over each conductor shall however be retained through out the run of the

conductor upto the end where lugs shall be fitted thereon for connections. The lugs shall be fitted by

means of approved < solder and flux such as a leap, and Eyre NO.7 liberally used. The joint shall be

mechanically strong and pressure tested.

2.6 DISTRIBUTION BOARDS AND PANELS:

General Requirements:

2.62 All distribution panels shall comply with I.E.E. Rules 60- 61. A clear distance of 0.91 b metre in front of the

switch board shall be kept. Where bare connections or attachments are provided 8t the back of the 'Switch

board the space behind the panel shall be either less than 0.299 meter or more than 0.762 main width there

shall be a passage way from the furthers outstanding part of any attachment or conductor. If the space behind

the switch board exceeds 0.70 main width there shall be a passage way from either end of the switch board

clear to height of 1.928 m width 0299,m. All wiring connection shall be made neatly and securely.

2.6.2 For corciots carrying more than 10 Amps. tinned cable sockets shall be used. All connections shall be so made

as to form their own diagram Circuit shall be clearly numbered to correspond t 1 wiring diagram Names of the

distribution boards shall be painted as directed by the Engineer-in-charge. All the switch fuse units and isolators

D.Bs. shall be complete with earthing studs lugs neutral bar link, H.R.C. fuses and of approved make.

2.6.3 Skeleton type panels shall have a rigid form work adequately braced and supported. The switch and distribution

boards shall be neatly arranged in the frame. The details of the frame work and the arrangement of switches

shall be got approved by the Engineer-in-charge before the panel is fabricated:

2.6.4 All cubical type panels shall have rigid supporting frames adequately braced over which sheet metal shall be

nearly secured. All switches, distribution boards e-c. shall be neatly arranged en the panels and all connections

made from the back of switches. The panels shall be rendered dust and vermin-proof. The interior of the panels

shall not be accessible to unauthorised persons.

2.6.5 The recess type boards shall be embeded in wall in a cupboard with a metal hinged door with locking

arrangement. In all recessed conduit work all distribution boards shall be recessed. Whet e recessing is not

possible, free standing panel may be provided as approved by the Engineer-in-charge.

2.6.6 All individual components i.e. switch fuse units D.Bs. etc. shall be connected by earth continuity wire of

appropriate size with the main earth bus of the panel D.H. etc. The panel switches or ').Bs. shall be earthed by

the less than 2 distinctive paths to earth. Earthing of metallic parts of exposed metal shall not be effected

through any structural metal work which houses the installation. Where metallic parts are not required to be

earthed and are liable to become alive should the installation of the contractor become defective such metallic

parts shall be separated by durable non-conducting material from any structural work.

(a) Power panels shall be 3 phase, 4 Wire, 400.230 volts for the distribution of 3 phase .01' single phase

power loads. Lighting panels shall be 3 phase 4 wire 400/230 volts for single phase lighting load

distribution on all 3 phase.

(b) All panels shall be done or protected front type with no mechanical or electrical defects. (c) . Bus bars

shall be of electrolytic copper or aluminium as specified and the properly tinned sizes as indicated on

applicable drawings as required.

(d) AU knock outs for branch circuits, conduit entries shall be drilled in und filled as required. For lighting

panels the top and bottom cover plates shall be removable type.

(e) Main disconnect device for all panel boards shall be of switches of disconnect type and of the size as

indicated shall be mounted directly below the panel or through a short thread conduit of required size.

(f) The main disconnect for all panel boards shall have an entry suitable for PVC armoured

cable from bottom.

(g) All panel boards shall be provided with an earthing terminal and lug for connection to the

grounding system.

(h) Temperature rise of all electrical parts shall not be more than 3000 with full load amseres at

room temperature. Buses shall be securely supported so that ordinary vibrations will not

cause any of the parts to become loose.

(i) All barriers and supports of current carrying parts shall be of moisture resistant insulating material and

shall not be adversely affected by arcing.

(j) The locations of panels shown in the drawings are only tentative. Panels nay be located at a place

approved by the Engineer-in-charge.

(k) All civil works connected with fixing such as grouting chasing and making good shall be the tenderer's

responsibility.

(m) Wires adequate capacity with proper size of lugs shall be used for inter connections.

(n) Panel should be self supported on angle channel iron frame work. It should be preferably of

bolted construction in case of transportation and flexibility. The frames shall be of the

required size for the mounting of the equipment on it. It shall be bolted or grouted rigidly alter

leveling and alignment.

(o) The cupboard and D.B. should be of such size so to be accommodated in the excising room as per I.S.

rules and I.S. codes of practice for installations of medium voltage switch gear.

(p) Fabrication drawing showing the detailed dimensions and panels and its components indicating the

frame work. earthing positioning of switches. D.Bs. cable boxes. adopter chambers etc. shall be

furnished to the Engineer-in-charge for his approval. All material to be got approved by the Engineer-

in-charge. Panel should be guaranteed for satisfactory operations for a period of one year after

(q) The panel should be painted with anticorrosive paint suitable for humid and salty atmosphere on two

coats of primer.

Switch Gears, Powers Panels D.B. and S.F. Us.

2.6.8 The main busbar shall have continuous current rating as specified with neutral bar having half of full load rating

of the phase busbar. The sizes of the bus bars shall be ~o selected that the current density in bar does not

exceed 150 amps. per sq.m. for copper. The length of bus-bar chamber should be as suitable length to fix all

the switches etc. as per the prevailing standards, clear spacing of two adjacent buses shall be 1 1/2" minimum

bar should be ltapted all alongwith colour coated 11 KV grade PVC tape. The maximum internal of support for

each unsupported length shall exceed 600 mm.

The bus bar shall be of copper/ alluminium and fabricated to the relevant standards specification. In case

alluminium bus bar is used special with high conductivity alluminium bu.s bar alloy E 91 C frame conforming to

E.S.S. 2898 shall be used. The current density shall not exceed 800A per sq. inch. Hylam barners will be

provided over the joints to prevent any short circuit.

The bus enclosings shall be made out not less than 16 gauge M.S. sheet construct on with angle iron support.

All interconnections between bus bars S.F. Us. and D. Bs. shall be of adequate size and details of such inter

connection shall be furnished to the Engineer-in-charge for his approval.

The bus bar shall be air insulated extensible type rectangular one. The bus bars chamber shall be dust tight by

providing gaskets secured properly so as to tender it vermin proof.

The Combination Fuse-switch unit should comply with IS 4064 BS 861 and BBS 2510 wherever applicable. It

should be suitable to accommodate High Rupturing Capacity Cartridge Fuse links complying with IS 2208 or BS

88 and having a certified rupturing capacity of not less than 35 MVA at 440 volts (AC5 duly). The switch gear

(panes. D. Bs. etc.) shall be installed generally as per IS-Part- I 3072 and las specified and shown in drawings.

All fuse switch units shall be provided with non-deteriorating HRC fuse links complying with IS 2208-1962 and

having rupturing capacity of 35 MVA at 415 volts. or as specified.

All switches above 60 amps. rating shall be provided with suitable size adapted boxes. All switches mounted on

the top of the busbars shall be provided with detachable type reverse entry adapter boxes. Suitably engraved

labels shall be provided for each circuit as well as for the board.

A meters sector switches and LMH metre shall be provided where specifically mentioned. Small wiring for the

inter-.connecting shall be colour coded and provided with numbered fuses for easy identification of circuits.

(a) The distribution boards should be totally enclosed metal clad complying with B. S. 214. The

M. S. sheet steel enclosures for recessed D. Bs. shall be of not less than 14 guage.

(b) The D. B. shall be with hinded door and the locking arrangements as approved by the

Engineer-in-charge.

(c) All the components shall be enclosed in the enclosure. The mounting of D. B. shall be got

approved by the Engineer-in-charge before carrying out the installation.

(d) The D. Bs. shall have proper size cut outs for conduits entry or cable entry as required and

these shall be made on site.

(e) Adequate spacing shall be provided inside the D. Bs. for easy removal of the fuses and carry

out the inter connection:

(f) A set of insulating barriers have to be provided between in coming breakers switches and

Switch fuse Units:

(a) All the D.P. T.P. and TP.N. switch fuse units shall be totally enclosed iron clad quick make,

quick dreak type to best Indian make conforming to the I.S. or B.S. 3185 specifications. All

the switch fuse units shall have mechanical interlock with a door, so that the door cannot be

opened when the swithches are in 'ON' position. The switches should be of double break

solation type to ensure safely.

(b) Each TP. & TP.N. switch fuse unit shall be earthed with two distinct earch connections.

(c) Suitable insulator shall be provided. between phase.

(d) There shall be suitable neturallink in the fuse box.

(e) All T. P. & T.P.N. switch fuse units shall be rated for 500 volts and D. P. (required for single

phase supply) and S.P.N. switches for 250 volts.

(f) The H.R.C. catridge fuse shall conform to H.S. 88 (1952).

The O.C.Bs. ACB shall be suitable for 400/440 volts 3 phase 50 cycle supply capable of

interrupting a fault MVA of not less than 31. The circuit breaker shall conform to the BSS-

936-1940 BSS 3659 with such tripping arrangement as may as required under special

specifications for the building. Efficient and foolproof mechanical interlocking shall be

provided for the safe operation and maintenance. The rate shall be inclusive of the first filling

2.7 Instrumentation :

The instruments and meters wherever necessary shall be housed in special sheet steel box located

between switch fuses units and bus bus bar chambers. The instruments etc. shall be mounted on the

hinged cover with heir dial flushed. All instruments shall have protective H. R. C. fuse links. All

interconnections and small wiring shall be neatly dressed arranged and duly coloured for easy

identification of circuits.

Meters shall be provided as required in the Schedule, Meters shall be dead head and be suitable for

400/440 volt 3 phase 4 wire 50 cycle (in balanced load) supply.

Each selector switch shall be 3 point and of minimum 250 volts grade with silver tipped contacts

suitable for metering circuits, current transformers shall be of 5VA burden and commercial metering

accuracy. indicating lamps shall be penal mounting type preferably of 250V grade. Every unit shall

be rewired and interconnected to the system for its required Indicating performance. Indicating lamps

shall have independent circuit fuse.

2.8 FIXING OF LIGHTING FIXTURES:

1. Location of fixtures their manner of fixing mounting height etc. are indicated in relevant drawing.

Actual location and levels shall however be arrived at site in co-ordination with other service etc and

prior approval of the Engineer-in-charge regarding the actual location. Manner of fixing shall be

obtained before the work is taken up in hand.

2. In all cases the contractor shall provide necessary interconnection wiring earthing painting etc. all

necessary for complete installation. The contractor shall also test and commission the fixtures during

completion of the work.

3. . General arrangement of fixtures layout is indicated in drawings. Care snail be taken to see that all

light fixtures are in a row in a room or particular area, are in absolute line and plump and are

symmetrically disposed with respect to finished surfaces of walls columns beams etc. .

4. The inter-connections wiring from the light outlet point up to the fixture shall be carried out by means

of flexible copper wire of 'section not less than 1.5 mm .

5. All fixtures suspended by means of conduits shall be done with all and socket joints or as per approved design.

2.9 Telephone System:

1. Empty conducting shall be done, recessed or exposed to surface along with pull boxes, junction

boxes and telephone outlet boxes, in areas and location' as indicated in the relevant drawing as per

materials and methods as described in regard to conducting under section "Wiring in Conduits"

except the G.I. pull wires of guage not. less than 20 SWG shall be kept pulled through conduits in all

sections so that in future telephone wires can be pulled easily.

1. Location shown on the drawing are approximate and final location shall be decided in the field by the

Engineer-in-charge.

SPECIFICATION FOR EARTHING.

1. Installation of Earthing Plates :

All installation of earthing shall conform to Indian Electricity Rules, 18.3043 latest edition and lEE. The copper

earth plates should be tinned before installation. The earth plates of copper 60 cm x 60 cm x 3.515 ~m thick

size as mentioned in the schedule be -in separate pits at least 150 cms to 300 cms. away from the building at a

depth necessary to reach moist earth surface but with a minimum depth of 2.5 mtr from the finished ground

level upto the top vertical dodge of earth electrode. The earth plate shall be throughly cleaned to remove all dirt

from the surface and be tinned property for electrical contact with the main ground. Each earth pit should be

provided with 38 mm. dia G,I. pipe 2.5 Mts. long or more depending upto the depth of pit, put over the vertical

edge of earth plate'(with top end of pipe provided with a closed to couyler). Alternative layers of salt and coke

shall be provided surrounding the plate. The pits shall be filled when the plates are in position and with the

approval of Engineer-in-charge.

To facilitate watering the pit, a concrete compartment sh(~uld be made with funnel with mesh and cover plate

as per rules provided in ISI regulation.lhe masonary endousures shall be25 8m x 25 cm x 25 cm (deep) with

C.l.lid of 23 cm x 30 cms size. After installation, the earthing resistance of each earth plate should be measured

by resistance m'eggar in the presence of Engineer-in- charge, three days after the completion of earthing work,

and the value should conform to regulations.

Signature of Contractor/s Executive Engineer