Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 10027 (2000): Composite Units of Air-break Switches andRewirable Type Fuses for Voltages Not Exceeding 650 V a.c.[ETD 7: Low Voltage Switchgear and Controlgear]

IS 10027:2000.

Wwfb?Wm

qaT?awf%-di dhTl%m@m@h?t?

650 Th@r+rm iTmT&fi?Iqy:

(w jJ?wJ7 )—..—

t Indian StandardI

COMPOSITE UNITS OF AIR-BREAK SWITCHESAND REWIRABLE TYPE FUSES FOR VOLTAGESNOT EXCEEDING 650 V a.c.-— SPECIFICATION

(First Revision )

ICS 29.120.40; 29.120.50

@ BIS 2000

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

IApril 2000 Price Group 10

,, !

Low Voltage Switchgear and Controlgear Sectional Committee, ET 07

FOREWORD

This Indian Standard ( First Revision) was adopted by the Bureau of Indian Standards, after the draft finalized bythe Low Voltage Switchgear and Controlgear Sectional Committee had been approved by the ElectrotechnicalDivision Council.

The majori~ of the switches being manufactured in India are metal-clad switches. Switches with insulated enclosuresare also available in large quantities. These switches and fise combination units, incorporating particularly rewirabletype fuses are being manufactured in the small scale sector, intended for domestic and similar installations.

This standard has, therefore, been brought out primarily to meet the requirements of the manufacturer and the usersin respect of rewirable type switch-fuse units for current ratings not exceeding 100 A and of duty categoriesAC-2 1A and AC-21%.

IS 13947 (Part 3): 1993 ‘Specification for low-voltage switchgear and controlgear: Part 3 Switches, disconnectorsand fuse combination units’ -has been published superseding IS 4064 (Part 1 and Part 2). It is, however, felt thatwhile revising 1S 10027 incorporating requirements contained in IS 13947 (Part 3), need for exclusively separatestandard is maintained in view of composite units and rewirable type fuses manufactured in small scale sectorintended for domestic and similar installations.

In the use of this standard, references shall have to be made to 1S2086:1993 ‘Specification for carriers and basesused in rewirable type electric fuses for voltage up to 650 V (third revision)’.

The object of this standard is to define:

a) The characteristics of the equipment;

b) The conditions with which the equipment shall comply with reference to:

1) operation and behaviour in normal service;

2) operation and behaviour in case of specified abnormal conditions, for example, short-circuiu

3) dielectric properties;

c) The tests “intended for confirming that these conditions have been met and the methods to be adopted forthese tests; and

d) The data to be marked on the equipment.

For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,observed or calculated, expressing the result of a test, shall be rounded off in accordance with IS 2:1960 ‘Rules forrounding off numerical values (revise~’. The number of significant places retained in the rounded off valueshould be the same as that of the specified value in this standard.

*

+

.

lS 10027: 2000

Indian StandardCOMPOSITE UNITS OF AIR-BREAK SWITCHES

,\ND REWIRABLE TYPE FUSES FOR VOLTAGESNOT EXCEEDING 650 V a.c. — SPECIFICATION

(First Revision)I SCOPE

1.I “Ibis standard covers requirements for compositeu]]its of air-break switches and rewirable type electricfuses with rated current not exceedirtg 100A intendedfor system voltages not exceeding 650 V a,c,

1.2 The switches incorporated in the composite unitsare intended for utilization category of AC-21Affrequent operational) and AC-21B (infrequentoperation),

1.3 The rewirable type tises, incorporated in compositeunits, shall conform to the requirements laid down in[S ~086

NOTE—It shall however be recognized that this impos’dsnorestriction on rewirable type fuse-combination of othercategories of duties or composite units incorporating cartridgetype fuses in which case reference shall be made to IS 13947

([’art 3).

NOTE — This standard shall cover only composite units

incorporating :

a) Air-break ‘on’ and ‘ofT switches of category AC-21Aand AC-2 t B and for rated current not exceedkrg 10OA,

b) Rewirable type of fkses only. and

c) Enclosure of metal-clad insulated types

2 REFERENCES AND DEFINITIONS

2.0 The Indian Standards listed in Annex D arenecessary adjuncts to this standard.

! 2.1 For the purpose of this standard, the following, definitions in addition to those given in IS 1885

(Part 17) and IS 13947 (Part 1) shall apply.

2.2 Switch (Mechanical) — A mechanical switchingdevice capable of making, carrying and breaking currentunder normal circuit conditions which may includespecitied operating overload conditions and also carryingfor a specified time currents under specified abnormalcircuit conditions such,as those of short-circuit.

2.3

NOTE — A switch maybe capable of making, but not breakingshort-circuit currents.

Fuse-Combination Unit — A combination of a

mechanical switching device and one or more fitses in acomposite unit, assembled by the manufacturer or in _....x

accordance with his instructions,

2.4 Switch-Fuse — A switch in which one or morepoles have a fuse in series in a composite unit.

2.5 Dependent Manual Operation (of a MechanicalSwitching Device) — An operation solely by means ofdirectly applied manual ener~j such that the speed andforce of the operation are dependent upon the action ofthe operator.

2.6 Independent Manual Operation (of a MechanicalSwitching Device) — A stored energy operator wherethe energy originates tlom manual power, stored andreleased in one continuous operation, such that the speedand force of the operation are independent of the actionof the operator,

3 CHARACTERISTIC@ OF EQUIPMENT

3.1 Summary of CharacteristicsThe characteristics of the equipment shall be stated interms of the following as applicable:

— Type of equipment (3.2)- Rated quantities (see 3.3)- Utilization category (3.3.7)— Dependent manual operation (see 2.5)— Independent manual operation (see 2.6)— Degree of protection (see Annex C)

3.2 Type of EquipmentThe equipment shall have.the following details:

a)

b)

c)

Number of Poles — Either single pole withneutral, double pole or triple pole with neutral.

Number oppositions — The equipment shall haveonly two positions, that is ‘on’ and ‘of~.

Kind of Current — The equipment shall bedesigned for use in single-phase or three-phasea,c. systems of rated frequency of 50 Hz.

1

IS 10027:2000

3.3 Rated Quantities

Rated qualities are assigned M indicated in 3.3.1and 3.3.2, but it is not necessary to establish all the ratedquantities listed.

3.3.1 Rated Voltages

Ali equipment is defined by the following rated voltages.

NOTE— Certain types of’equipment may have more than one

rated voltage or may have a rated voltage range.

3.3.1.1 Rated operational ‘;oitage (U.)

A rated operational voltage of an equipment is a vahteof voltage which combined with a rated operationalcurrent, determines the app~kzttion of the equipment andto which the relevant tests and the utilization categoriesare referred.

For single pole equipment, the rated operational voltageis geuerally stated as the voltage across the pole.

For multiple equipment, it is generally stated the voltagebetween phases.

NOTESI for certain devices and pWtiCLdaI’ applications. a different

]methodof stating U. may apply; this should be stated inthe relevant product sttudard:

2 For nrrr!tiple equipmcn: ior use on polyphase circuits, adistinction may be made between:

a)

b)

c)

d)

e)

Equipment for use in system where a single fault toearth will not cause the full phase to phase voltage toappear across a pole (that is unearthed and neutralearthed systems);

Equipment for use in system where a single fault toearth wilI cause to full to phase to phase voltage toappear across a pole (that is phase earthed systems);

An equipment Imay lE assigned a number ofcombinations of rated operational voltages and ratedoperational current! or powers for different duties andutilization categories,

An equipment may bc assigned a number of ratedoperational voltages and associatedmaking and brakingcapacities for ciiflcreat duties and utilizationscategories; :~nd

Attention is drawn to the fact that the operationalvoltages may differ from the working voltages of an

equipmenr.

3.3.1.2 Rated insulation voltage (U.)

The rated insulation voltage of an equipment is the valueof voltage to which dielectric tests voltage and creepagedistances are referred.

In no case shall the maximum value of rated operationalvoltage exceed that of the rated insulation voltage.

NOTE — For equipment not having a specified rated insulationvoitage, the highest value of the rated operational voltage isconsidered to be the rated insulation voitage.

3.3.1..3 Rated impulse withstand voltage (~~P)

The peak value of art impulse voltage of prescribedform ar,d polarity which the equipment is capable ofwithstanding without failure under specified conditionsof test and to which the varue of the clearances arereferred.

The rated impulse withstand voltage of an equipmentshall be equal to or higher than the value stated for thetransient over voltages occurring in the circuit in whichthe equipment is fitted.

3.3.2 Currents

An equipment is defined by the following currents,

3.3.2.1 Conventional free air thermal current (IJ

‘The conventional free air thermal current is themaximum value of test current to be used for temperaturerise tests of unenclosed equipment in free air as given inTable 1.

The value of the conventional free air thermal currentshall be at”leastequal to the maximum value of the ratedoperational current (see 3.3.2.3) of the unenclosedequipment.

Free air is understood to be air under normal conditionsreasonably free from draughts and external radiation.

NOTESI The current is not a rating and is not mandatorily marked

on the equipment.

2 An unenclosed equipment is an equipment supplied.by themanufacturer without an enciosure or an equipmentsuppiied -by the manufacturer with an integrai enclosurewhich is not normaliy intended to be the sole equipmentprotective enciosure.

3.3.2.2 Conventional enclosed thermal current (1J

The conventional enclosed thermal current is the valueof current stated by the manufacturer to be used for thetemperaturerise tests of the equipment when mountedin a specified enclosure, Such tests shall be inaccordance with 5.3 and are mandatory if the equipment

.,

L

Table’1 Temperature Rise Limits(Cluuxes 3.3.2.1,5.3,7.2.2, and7.4.6)

SINo(1)

i)

ii)iii)iv)

~)

vi)

Type of’ Nlaterial and Description Temperature Riseof Part Limit

(2) (3)

Conlact parts (main and auxiliary contacts):a) Copper:

\ :nintcrrupted duty 45 kb) Silver or silver-faced (see Note I) (see Note 2)c) All other metals or sintered metals (see Note 3),

Bare conductors (see Note 2)Metallic parls acting as springs (see Note 4)Metallic parts in contact with (see Note 5)insulating materials

Terminals for external insulated 70 Kconnections (see Note 6)

Manual operating means (handles, Icvers, wheels, etc):

IS 10027:2000

If the equipment is normally intended for use inunspecified enclosures, the test is not mandatory if thetest for conventional free air thermal current (IJ hasbeen made. In this case, the manufacturer shall beprepared to give guidance on the value of enclosedthermal current or the derating factor.

NOTES1

2

3a) Parts of lme~al 15 Kb) Parts of insulating material 25 K

NorEs1 The expression ‘siLver-faced’includes solid silver inserta

as well as electrolytically deposited silver, provided that,in the latter case, the temperature rise requirement of 7.4.6are satisfied.Contacts faced with other materials, the contact resistance01 which is not significantly altered by oxidation, aretreated as silver-faced contacts,

2 Limited solely by the necessity of not causing any damageto adjacent parts.

3 To be speciiied according to the properties of the metalsused and limited by the necessity of not causing artydamage to adjacent parts.

4 The resulting temperature shall not reach a value suchthat the elasticity of the material is impaired. For purecopper, this implies a total kmpcrature not exceeding

75°c.

5 Lin]itd solely by the ;mccssi!yolnot causing any damage10 insulating materials.

(1 ‘[!:c telnperature rise limit 0171JK is a value based on the,.,~:licntional test of 7.2.2. An equipment usedor testedLInderinstalIation conditions Inay have connections thetypc, nature and disposition ot’which will not be the sameas those adopted for the test; a different temperature riseof terminal may result and it may be rejected or accepted.

is described as enclosed equipment in the manufacturer’scatalogues and normally intended for use with one ortmoreenclosures of specified type ami size (see Note 2).

The vaiue of the conventional enciosed thermal currentshaii beat ieast equai to the maximum vaiue of the ratedopet-ational current (see 3.3.2.3) of the enclosedequipment,

‘t’hiscurrent is not a ratir.g and is not mandatorily markedon the equipment.

The conventional enclosed thermal current value may befor unventilated equipment in which case the enclosure usedfor the test shall be of the size stated by the manufactureras being the smallest that is applicable in service.Alternatively, the value may be for a ventilated equipment

according to the manufacturer’s data.

An enclosed equipment is an equipment normally intendedfor use with a specified type and size of enclosure or

intended for use with more than one type of enclosure.

3.3.2.3 Rated operational currents (Ic) or rated

operational powers

A rated operational current of an equipment is stated bythe manufacturer and takes into account the ratedoperational voltage (see 3.3, 1.1), the rated frequency(see 3.3.3), the rated duty, the utilization categories andthe type of protective enclosure, if appropriate.

In the case of equipment for direct switching ofindividual motors, the indication of a rated operationalcurrent may be replaced or supplemented by anindication of the maximum rated power output, at therated operational voltage considered, of the motor forwhich the equipment is intended. The manufacturer shailbe prepared to state the relationship assumed betweenthe operational current and the operational power, if any.

For the purpose of this standard, the preferred vaiues ofrated current shall be 16, 32, 63 and 100A.

3.3.2.4 Rated uninterrupted current (Iu)

The rated uninterrupted current of an equipment is avalue of current, stated by the manufacturer, which theequipment can carry in uninterrupted duty.

3.3.3 Rated Frequency

The supply frequency for which an equipment isdesigned atrd to which the other characteristic vaiuescorrespond.

For the purpose of this standard, the rated frequencyshail be 50 Hz.

3

IS 10027:2000

3.3.4 Ruted Muking CcipacI&

The rated making capacity of’an equ-ipment is a valueof current, stated by the manufacturer, which theequipment can satisfactorily make under specifiedmaking conditions.

The making conditions which shall be specified are:— the applied voltage— the characteristics of the test circuit

The rated making capacity is stated by reference to berated operational voltage and rated operational current,according to the relevant product standard.

NOTESI I-’ora.c., rated making capacity is expressed by the r,m.s,

vah]c of the symmetrical crrmporumtof the ccrrren~assumedto be crmstant.

~ For a.c. the peak value of the current during the first half-CYCkS foIlowing the closing of the main contacts of thecquipmeot may be appreciably greater than the peak valueof the current under steady state condition used in thedetermination of making capa~ity,depending on the power-i’hctorof the circuit and the instant orr the voltage wavelvhen closing occurs.

3 An equipment should be capable of closing on a currenthaving the a.c. component equal to that which defines itsrated making capacity, whatever the value of the inherentd.c. component, within the limits resulting from the power-Factorsindicated in the Indian Standard.

The rated making capacity is stated by reference to the ratedoperational voltage and rdted operational current and tothe utilization category according to Table 2.

3.3.4.1 For a.c. the making current is expressed by ther.m.s. value of the periodic component of the current.

3.3.5 Rated Breaking Capaci@

The rated breaking capacity of an equipment is a valueof current, stated by the manufacturer, which theequipment can satisfactorily break, under specifiedbreaking conditions.

The breaking conditions which shall be specified are:— the characteristics of the test circuit— the power frequency recovery voltase

The rated breaking capacity is stated by reference to therated operational voltage and rated operational current.

An equipment shall be capable of breaking any value ofcurrent up to an including its rated breaking capacity.

NOTES

1 A switching device may have more than one rated breakingcapacity, each corresponding to an operational voltage anda utilization category (AC -2 I A or AC-21 B in this case).

Table 2 Verification of Rated Making and Breaking Capacities (see 7.4) Conditions forMaking and Breaking Corresponding to the Various Utilization Categories

(Clauses 3.3.4,3.3.7 and 7.4.4)

[[tiliz,~tjon Rated Operational Make-Break Number ofCategory Current IJIe Ujua Cosa Operating Cycles.AC-2IA All values 1.5 1.05 0,95 5and AC-2 1B

—.

ii Ihcr-c

1= Making current

IL = Breakin: c~lrreat

1, = Rated operational current

1’ = Applied voltage

[! = Rated operational voltage

1 = Power frequency recovery v(}lP.ige

4

..—

lS 10027 :2000

2 Fora.c, therated breaking capaeity isexpressed by thermsvalue ot’symmetrical component ot’the current.

The rated breaking capacity is stated by reference to therated operational voltage and rated voltage current andto the utilization categories according to Table 3and 3.3.5.

example, to disconnectors normally only operated toprovide isolation for maintenance work or switchingdevices where the fuselink blade forms the movingcontact.

Table 3 Utilization Categories(Clauses 3.3.5 and 3.3.7)

3.3.6 Ra{ed Fused Shor~-Civcuit Current

The rated fused short-circuit current of the equipmentis the value of prospective current, stated by themanufacturer, which the equipment can satisfactorilywithstand until the fuse blows.

Nature of Frequent Infrequent TypicalCurrent Operation Operation Applications

Alternating AC-21A AC-21B Switching ofcurrent resistive loads

includingmoderateoverloads

The value of rated fused short-circuit current shallbe as follows: The utilization categories referred to in Table 2 and 3

do not apply to an equipment normally used to start,

Rated Current Fused Short-Circuit accelerate and/or stop individual motors. The utilization

(A) Current (A) (r.m.s.) categories for such an equipment are dealt with in

16 2000 Annex A of IS 13947 (Part 3).

3263

40004000

3.3.8 Operational Performance

100 4000 Tests concerning the verification of the operational

The standard power factor shall be 0.8 and the ratioperformance of an equipment are intended to veri& thatthe equipment is capable of making and breaking without

between the peak and the r.m .s. value of current shall failure, the currents flowing in its main circuit for thebe 1.47. intended use.

A power factor of O.4 may be agreed to between themanufacturer and the user for special application, ifnecessary.

The number of operating cycles and the test circuitparameters for the operational performance test for thevarious utilization categories are given in Tables4 and 4A.

3.3.7 Utilization CategoryThe test conditions are specified in 7.6.1.

The utilization categories define the intendedapplications and are given in Table 3.

Each utilization category is characterized by the valuesof the currcmt and vokages, expressed as multiples ofthe rated operational current and the rated operationalvoltage, as well as the power-factor or time-constantsof t!le circuit. The conditions for making and breakinggiven in Table 2. Correspond in principle to theapplications listed in Table 3.

3.3.9 Durability

NOTE — The term durability has been chosen instead ofendurance in order to express the expectancy of the number ofoperating cycles which can be performed by the equipmentbefore repair or replacement of parts, Moreover the termendurance is also commonly used to cover operationalperformance as defined in 3.3.8 and it was deemed necessorynot to use the term endurarrcein this standard in order to avoidconfusion between the two concepts,

3.3.9.1 Mechanical durability

-.. —

The designation of utilization categories is completed With respect to its ~esistance to mechanical wear, an

by the suffix A or B according to whether the intended equipment is characterized by the number, -stated in

applications require frequent or infrequent operations 7.7.1, of this standard of no-load operating cycles (that

(see Table 3). is without current at the main contacts) which can beeffected before it becomes necessary to service or replace

Utilization categories with suffix B are appropriate for any mechanical parts; however normal maintenance

devices which, due to design or application, are only according to the manufacturer’s instructions may beintended for infrequent operation. This could apply, for permitted for equipment designed to be maintained

5

,’

IS 10027:2000

Each operating cycle consists of one ciosing operation NOTE — Preferred number of no-load and on-load operating

followed by one opening operation. cycles‘aregiven in Table 4.

The equipment shall be mounted according to the 4 STANDARD CONDITIONS FOR OPERATIONmanufacturer’s instructions for the test. IN SERVICE

3.3.9.2 Electrical durabili@ 4.1 Normal Service Condition

With respect to its resistance to electrical wear, anEquipment complying with this standard shall be capable

equipment is characterized by the number of on-loadoperating cycles corresponding to the service conditions

of operating under the standard conditions given in 4.1.1to 4.1.4. For non-standard conditions in service (see

given in 7.7.2 which can be made without repair orAnnex A).

replacement.

Table 4 }’edification of Operational Performance Number of Operating CyclesCorresponding to the Rated Operatio~al Current

(Clauses 3.3.8,3.3.9.2. and7.6.l.1)

Rated Number of Number of Operating Cycles

Operational Operating I 1Current Ic Cycles per a.c. a.c.

“Hour A Categories B Categories

~1—————lWithout With Total Without With Totalcurrent current current current

(1) (2) (3) (4) (5) (6) (7) (8)

OICIOO 120 8500 1500 10000 1700 300 2000

Table 4A Test Circuit Parameters for Table 4

Utilization Rated Operational Makbrg (I) Breaking

Category Current 111 U)ue cos a 1,11 u m. .COSa

AC-21A A1lvalues 1 1 0.95 I I 0.95

and AC-2 1B

where

1= Making current

1, —— Breaking current

IL —— Rated operational current

[J = Voltage before make (applied voltage)

11< = Rated operational voltage

u, = Power frequency recovery voltage

For a.c. the mti[ng current is expressed by the r.m.s, value of the periodic component of the current.

6

4.1.1 A rnbient A ir Temperature

The ambient air temperature does not exceed 40°C andits average over a period of 24 h does notexceed + 35-C.

NOTE — Equipment intended to be used in ambienttemperaturesabove + 40°C(for example, in forges,boiler rooms,tropical countries or below-5°C shall be designed or usedaccording to an agreement between manufacturer rtttd user,Information given in tbe manufacturer’s catalogue may takethe place of such an agreement.

4.1.2 A Ititude

The altitude of the site of installation shall not exceed2000 m.

NOTE — For instalIations at higher altitudes, it is necessary totake into account the reduction of the dielectric strength and ofthe cooling effect of the air. Equipments used shall bedesigned or used according to an agreement betweenmanufactumr anduser. Information given intbemanufactutvr’s

catalogue may take the p]ace of such an agreement.

4.1.3 Atmospheric Conditions

The air is clean and its relative humidity does not exceed50 percent at a maximum temperature of +40°C. Higherrelative humidities may be permitted at lowertemperature, for example, 90 percent at +20”C. Careshall be taken of moderate condensation which mayoccasionally occur due to variations in temperature.

4.1.4 Condition of Installation

The, equipment is installed in accordance with themanufacturer’s instructions.

5 STANDARD COND-ITIONS FORCONSTRUCTION

5.1 Mechanical Design

5.1.1 General

Materials shall be suitable for the particular application.The enclosed and the open positions of the equipmentshali be definite and shall be clearly indicated eitheradjacent to the actuator or by the position of the latter.If symbols are used, ‘I’ and ‘O’ shall be used to indicatethe closed and open positions respectively. The positionindicator shall be connected to the moving contacts in areliable way; the handle may form such art indicator,provided it cannot indicate the off position unless allthe moving contacts are in the open position.

IS 10027:2000

The operation shall be independent manual.

5.1.2 Operating Handle

The operating handle of the equipment shall be insulatedfrom the live parts for the rated insulation voltage.Moreover:

a)

b)

if it is made of metal, it xhall be capable ofbeing satisfactorily connected to a protectiveconductor unless it is provided with additionalreliable insulation; and

if it is made of or completely covered byinsulating material, arty internal metal parts,which might become accessible in the event ofinsulation damage, shall also be insulated fromlive parts for the rated insulation voltage orshall be capable of being satisfactctrilyco~nected to a protective conductor.

5,1.3 Terminals

S.1.3.1 Constructional requirements

All parts of terminals which maintain contact and carrycurrent shall be of metal having adequate mechanicalstrength, The use of aluminium conductors as well ascoppet conductors shall be taken into account.

Terminal connections shall be such that the conductorsmay be connected by means of screws, springs or otherequivalent means so as to ensure that the necessarycontact pressure is maintained.

Terminals shall be so constructed that the conductorscan be clamped between suitable surface without anysignificant damage either to conductors or terminals.

Terminals shall not allow theconductors to be displacedor be displaced themselves in a manner detrimental tothe operation of equipment and the insulation voltageshall not be reduced below the rated values.

Examples of terminals are given in Annex B.

5.1.3.2 Connecting capacity

The manufacturer shall state the type (rigid solid orstranded or flexible), the minimum and the maximumcross-sections of conductors for which the terminal issuitable and, if applicable, the number of conductorssimultaneously connectable to the terminal. However,the maximum cross-section shall not be smaller than

..

7

IS 10027:2000

that stated in 7.2’ for the temperature rise test and the be readily accessible during installation. Clampingterminal shall be suitable for conductors of the same screws and nuts shall not serve to other componenttype (rigid solid or stranded or flexible) at least 2 sizes although they may hold the terminals in place or preventsmailer, as given in the appropriate CO1of Table 5, them from turning.

Terminals for connection to external conductors shallbe readi!y accessible during i]iscdlatiort.

Clamping screws and nuts shali not serve to fix any othercomponent although they may hold the terminals in placeor prevent them from turning.

Table 5 Standard Cross-St>ction of Aluminiumand Copper Conductors Corresponding

to the Rated Currents

(Clauses 5.1.3.2 Gnd 7.2.2)

S1No. tlangeofTest Muminium CopperCurrent Conductor Conductor

Size (mm2) Size (mmz)

(1) (2) (3) (4)

f)ii)111)iv)v)vi)vii)VIII)ix)

~)

o-8s.]~

12-15

15-20

20-25

25-32

32-5050-65

65-85

85-1oo

1.5!.52.54.06

10162s35

50

1.01.52.52.54.06.0

101625

35

5.1.3.3 Additional requirements for equipment

provided with a neutral pole

When an equipment is provided with a pole intendedonly for connecting the neutral, this pole shall be cleariyidentified to that effect by the letter ‘N’ (see 5.1.3.5).

A switched neutral pole shal~break n~t before and shallmake not after the other poles,

For equipment having a value of conventional thermalcurrent not exceeding 63 A, the value shall be identicalfor all poles.

For higher conventional thermal current values, theneutral p.oiemay have a value of conventional thermalcurrent different from that of’the other poles, but notless than half that value or 63 A, whichever is the higher.

5.1.3.4 Connections

Term inals for connection to external conductors shall

5.1.3.5 Terminals identl~cation and marking

Terminals shall be clearly and permanently identifiedin accordance with IS 11353.

Terminals intended exclusively for the neutral conductorshall be identified by the letter ‘N’.

5.1.4 Earthing

5.1.4.1 The assembly comprising metallic chassis,framework and the fixed parts of the metal enclosuresshall be provided with two separate earthing terminals.These terminals shall be proved over and above all othermeans provided for securing metallic enclosures (armouror other metallic covering) of current-carrying cables.

5.1.4.2 The earthing terminals shall be readilyaccessible and so placed that the earth connection ismaintained when the cover of any other movable partsis removed.

5.1.4.3 -The earthing terminals shall be of adequate size,be protected against corrosion and shall be metallicallyclean. Under no circumstances shall a movable metalpart of the enclosure be insulated from the part carryingthe earthing terminals when the movable part is in place.

5.1.4.4 The earthing terminals shall be identified bymeans of the symbol marked in a legible and indeliblemanner on or adjacent to the terminals.

5.2 Enclosures

The enclosure seal be so arranged that, when it is opened,the terminals as well as all parts requiring maintenance,as prescribed by the manufacturer, are readily accessible.

5.2.1 Sufficient space shallbe left in the interior of theenclosure for the accommodation of external conductorsfrom their point of entry into the enclosure as far as theterminal.

5.2.2 The movable parts of the protective enclosureshall be firmly secured to the fixed parts by a devicesuch that they cannot be accidentally loosened ordetached owing to the effects of operation of theequipment.

8

IS 10027:2000

5.2.3 Theenclosure oftlieunit shtdlbe sodesignedasto allow the cover to open without the use of tools andthe following requirements shall be fulfilled:

a) It shall not be possible to open the cover unlessthe switch is in the ‘off position.

b) With the cover of the enclosure open, means shallbe provided so that:

1) the fastening devices do not get lost;2) it is not possible to close the switch; and3) there is no possibility of accidental contact

with the live parts.

5.2.4 Degree of Protection

Degree of protection as declared by the manufacturershall be verified in accordance with Annex C.

5.3 Temperature Rise

The temperature rise of the several parts of an equipment,measured during the test carried out under the conditionsspecified in 7,2, shall not exceed the values specified inTable 1. The temperature rise limits given therein areapplicable only if the ambient air temperature remainswithin the limits given in 4.1.1.

5.4 Dielectric Properties

The equipment shall be capabledielectric tests specified in 7,3.

5.5 Operating Conditions

of withstanding the

The equipment shall be operated in accordance with themanufacturer’s instruction, if any, especially forequipments with dependent mamfal operation where themaking and breaking capacities may depend on the skillof the operator,

6 PRODUCT INFORMATION

6.1 I’he following information shall be submitted bythe manufacturer:

– Detailed drawing of the equipment indicatingtype and design of the equipment covering allparameters given at 5.

6.2 Markings

The equipment shall be marked in a durable manner withthe data given below:

a) Indication of the open and closed position. If

b)c)d)

e)

og)h)

symbols are used, they shall indicate the closedand open positions respectively as follows:

I ON (Power)O Off (Power)

The following data shall also be marked on theequipment but need not be visible from the frontwhen the equipment is mounted.

Manufacturer’s name or trade-mark;Type designation as per 6.1 and serial number;Rated operational current (or rated power) at therated operational voltage and utilization category(see 3.3.1,3.3.2 and 3.3.4);Value (or range) of the rated frequency or theindication;Rewirable fuse type and maximum rated current;Ref to IS 10027 if certified by BIS;Degree of protection of enclosed equipment;

The following terminals shall be identified:

j) line and load terminals;k) neutral pole terminal, if applicable, by the lever

‘N’;

The following data shall be made available in themanufacturer’s published information:

m). rated insulation voltage; andn) rated fused short-circuit current.

6,3 BIS Certification Marking

Theequipment may also be marked with Standard Mark.

6,3,1 The use of the Standard Mark is governed bythe provisions of Bureau of IndidnBtandarak Act, 1986and the Rules and Regulations made thereunder. Thedetails of conditions under which the Iicence for the useof Standard Mark may be granted to manufacturers orproducers may be obtained from the Bureau of IndianStandards.

7 TESTS

7,0 Kinds of Tests

7.0.1 General

Tests shall be made to prove compliance with theteq@ements l~id down in this standard.Tests are as follows:

– Type tests which shall be made on representativesamples of each particular equipment.

,— Routine tests which shall be made on each

I1

I

9

IS “1OO27:2000

individual piece of equipment manufactured tothis standard.

The above tests may consist of test sequence of requiredby purchaser or certifying authority.

Tbe tests shall be carried out by the manufacturer, at hisworks or at any suitable laboratory directed by purchaser/or certification authority.

7.0.2 Type Tests

Type tests are intended to verify compliance of thedesign of a given equipment with this standard.

They may comprise, as appropriate, the verification ofi

- Constructional requirements (5),– Temperature rise (7.2).-- Dielectric properties (7.3),– Making and breaking capacities (7.4),– Rated fused short-circuit current (7.5),- Mechanical durability (7.7.1),- Electrical durability (7.7.2),- Operational performance (7.6.1), and– Degree of protection of enclosed equipment

(Annex C).

7.0.3 Acceptance Test

They comprise all tests at 7.0.2 except the following :– Rated fused short-circuit current (7.5),– Operational performance (7.6.1),— Electrical durability (7.7.2), and— Degree of protection of enclosed equipment

(Annex C).

7.0.4 Routine Tests They comprise :

— Operation tests (7;8. 1), and

- Dielectric test (7.8.2).

7.0.5 S~lmpling Tests

Sampling tests may also be made to verify specificproperties or characteristics of an equipment, either onthe manufacturer’s own initiative, or by agreementbetween manufacturer and user. The tests may comprise:

a) Functional tests, and

b) Dielectric tests.

—....—

7.1 General Conditions of Test

7.1.1 The equipment to be tested shall agree in all itsessential details with the drawings of the type which itrepresents. Unless otherwise specified, each type testshall be carried out on an equipment in a clean and newcondition.

7.1.2 For the tests, the equipment shall be mounted andinstalled as indicated by the manufacturer. The detailsof the installation (type and size of enclosureif any, size of conductor, etc) shall be part of the testreport.

Unless otherwise stated, the test shall be made with thesame kind of current (and, in the case of a.c. the samefrequency and with the same number of phases) as inthe intended service.

If for convenience of testing, it appears desirable toincrease the severity of a test (that is to adopt a higherrate of operation in order to reduce the duration of thetest), this may be done only with the consent of themanufacturer.

NOTE—Equipmentundertestshallbemountedcompleteonits own support or an equivalent support and connected as innormal service, in accordance with the manufacturer’sinstructions and under the ambient conditions statedin 4.1.1.

7.2 Verification of Temperature Rise Limits

7.2.1 Ambient Air Temperature

The ambient air temperature shall be measured duringthe last quarter of the test period by means of at leasttwo thermometers or thermocouples equally distributedaround the equipment at about half its height and at adistance of about 1 m from the equipment. Thethermometers or thermocouples shall be protectedagainst air currents heat radiation and indicating errorsdue to rapid temperature changes.

7.2.2 Temperature Rise Tests of the Main Circuit

The equipment shall be mounted approximately as underusual service conditions and shall be-protected againstundue external heating or cooling.

When temperature rise tests are made cm an enclosedequipment, no openings giving false ventilation shallbe allowed.

For equipment not supplied with an enclosure but

10

IS 10027:2000

intended to be used in an enclosure, the test for the ratedcurrent corresponding to an enclosed mounting shall becarried out in a chamber as stated by the manufacturerto be equivalent to the smallest enclosure that isapplicable in service.

It is permissible, before beginning the tests, to operatethe fuse-combination unit a few times with or withoutload.

The temperature rise is made at the rated current.

Tests xhall be made at frequency between 4562 Hz.

and

Fuse-combination units shall be fitted with fise-wirehaving a rated current equal to the rated current of thecombination unit.

The test shall be made over a period of time sufficientfor the temperature rise to reach a steady-state value,but not exceeding 8 h. In practice, this condition isreached when the variation does not exceed l°C/h.

NOTE — In practice, to shorten the test the current may beincreased during the first part of the test; and may be reducedto the specified test current afterwards,

At the end of the test, the temperature rise of the different partsof the main circuit shall not exceed the values specified inTable 1,

The connections shall be single-core, PVC insulated,aluminium cables or copper cables with cross-sectionalareas as given in TaWe 5.

In case of mt,dtipole equipment tested with a.c. the testshall be carried out with single-phase current, with allpoles connected in series, but only as far as the errorsresult ing from magnetic influences can be neglected.

The connections shall be in free air and spaced not lessthan the distance existing between the terminals.

The minimum length of each temporary connection ‘fromterminal to terminal shall be:

a)

b)

7.2.3

1 m for cross-sections up so and including16 mm’; and2 m for cross-sections larger than 16 mm2.

Measurement of the Temperature

The temperature of the different parts shall be measuredby means of the thermocouples at the nearest accessibleposition to the hottest spot.

Good heat conductivity between the thermocouple andthe surface of the part under test shall be ensured. Thethermocouple wire and junction shall be such that theydo not influence the temperature rise of the part undertest.

7.2,4 Temperature Rise of a Part

The temperature rise of a part is the difference betweenthe temperature of this part measured in accordance

,—

with 7.2.3 and the ambient air temperature measuredin accordance with 7.2.1.

7.2.5 Corrections

If the anibient air temperature during the testis between+1O“C,no correction is necessary to take account of theambient temperature during the test and the values ofTable 1 are the limiting values oftemperature rise. Ifthe ambient air temperature during the test exceed +40”Cor is lower than i-10°C,the manufacturer and the usershall make a special agreement.

7.3 Verification of Dielectric Properties

7.3.1 Condition of the Equ@ment for Tests

Dielectric tests shall be made on new equipmentmounted approximately as under usual serviceconditions, including internal wiring, and in a drycondition.

When the base of equipment is of insulating material,metallic parts shall be placed at all the fixing points inaccordance with the conditions of normal installationof the equipment and these parts shall be considered aspart of the frame qf the equipment. When the equipmentis in an insulating enclosure, the latter shall be coveredby a metal foil connected to the frame. If the.operatinghandle is metallic, it shall beconnected to the frame; ifit is of insulating material, it shall be’covered by a metalfoil connected to frame.

Equipment not supplied with an enclosure but intendedto be used in an enclosure shall be tested in an enclosurestated by the manufacturer to be equivalent to thesmallest that is applicable in service.

When the dielectric strength of the equipment isdependent upon the taping or leads or the use of specialinsulation, such taping or special insulation shall alsobe used during the tests.

11

IS 10027:2000

7.3.2 Application of the Test Voltage

The test voltage shall be applied for one minute asfollows:

.a) With the contacts closed:1) between all live parts of all poles connected

together and the frame of the equipment; and2) between each pole and all the other poles

connected to the frame of the equipment.

b) With the contacts open:I) between all live parts of all poles connected

together, and the frame of the equipment and2) between the terminals of one side connected

together, and.the terminals of the other sideconnected together.

For the purpose of the above tests, an insulated neutralis to be considered as a pole of the equipment.

7.3.3 Value of the Test “Voltage

The test voltage shall have a sinusoidal waveform, anda frequency between 45 Hz and 62 Hz. The source ofthe test voltage shall be capable of supplying a short-circuit current of at least 0.5A.

Unless otherwise specified, the values of the test voltageshall be 2000 V and 2500 V respectively for 240 V and415 V rated equipment.

7.4 Verification of Rated Making and BreakingCapacities

7.4.1 Condition of the Apparatus for Tests

The apparatus under test shall be mounted complete inits own enclosure and any apertures normally closed inservice shall be closed for the test. For app~atus notsupplied with an enclosure but intended to be dsed in anenclosure, the test shall be carried out in an enclosurestated by the manufacturer to be equivalent to thesmallest that is applicable in service. The operatingmechanism shall be operated in a manner similar to thatstated by the manufacturer as being normal.

While carrying out the test, fuse-links shall be replacedby links of negligible impedance.

7.4.2 Test Procedure

The test circuit shall be as described in 7.4.3, Themechanical switching device shall be closed and opened

5 times with an interval of approximately 30s betweenoperations.

During each make-b$eak operating cycle, the equipmentneed only stay in the closed position for.a period longenough to allow the switching operation to be completedand to enable the current value to be established and themoving parts of the switching device to come to rest.After each operating cycle, the recovery voltage shallbe maintained for at least O.1s.

The test voltage and the lqa~ shall be applied to theappropriate terminals of the apparatus. For apparatusin which a moving contact remains connected to one ofthe terminals when the apparatus is in the open position,this test shall be repeated with the supply and loadconnections interchanged, unless the terminals arespecifically and clearly, marked for load and supply.

7.4.3 Test Circuit for the Verification of the Rated

Making and Breaking Capacities

Figures 1,2 and 3 give the diagram of the circuits to beused for the tests.

The resistances R, and Rz and the reactance L, and Lz

of the test circuit shall be.adjusted to satis~ the specifiedtest conditions. The resistors shall be air cored, Theyshall always be connected tolhe resistors and their valuesmay be obtained by series coupling of individualreactors. Parallel connecting of reactors is permittedwhen these reactors have practica~y the same timeconstant. ,.

The test circuit loads L, and R, shaIl be connewed onthe load side of the apparatus,

The prospective short-circuit current at the point ofconnection to the supply terminals of the apparatus shallbeat least 10 times the value of the test current.

All parts of the apparatus normally earthed in service,including its enclosure, shall be insulated from earth andconnected to a point as indicated in Fig, 1.,2 and 3.This connection shall include a reliable device D (suchas a fuse consisting of a copper wire of 0.1 mm diameterand not less than 50 mm length) for the detection of thefault current and, if necessary, a resistor limiting thevalue of the prospective fault current to about 100 A.Any artificial neutral shall be substantially inductive,and permit a prospective fault current of at least 100A.The test circuit shall be directly earthed.at one pointonly and the position of this point shall be stated in thetest report.

—.. .—

12

For tests corresponding to utilization category ‘AC -21AorAC-21 B’ it is not necessary to adjust the oscillatorytlequency of the prospective transient recovery voltage.

7.4.4 Test Quantities

s

hL1

s supplyR,. A’, Adjustable resistors[.,..L, Adjustable reactorsR: Resistor for limiting the current in device Dr] Device for detection of a fault current.t Equipment under test8 Temporary connect ion for prospective current calibration(1, ’10current recording oscilloscopes(). ,03 To voltage recording oscilloscopes,.

Voltmeter

FIG. I [) IA(,RAMcw TIm “hsr ( ‘IXCIJTFOR SINGLE-P• LH

ECRJIPMIiNTONISINGLI-PiIASE a.c.

IS 10027:2000

The tests shall be performed with values stated by themanufacturer in accordance with Table 2.

The tests shall be taken as valid if the values recorded inthe test report differ from the values specified only withinthe following tolerances:

a) Currentb) Voltagec) Power-factord) Time-constant

s

?

LR2

L2

v

‘2=t-

+ 5 percenti 5 percent~ 0.05i 15 percent

N

f?,

----- -

‘2@’ffE~(4

0,

1

1

+

s supplyN To the neutral point or mid-point of the d.c, supplyR,, R, Adjustable resistorsL,, L, Adjustable reactorsR3 Resistor for limiting the current in device D

D Device for detection of a fault currentA Equipment under testB Temporary connection for prospective current calibrationo, To current recording oscilloscopes0,,03 To voltage recording oscilloscopesv Voltmeter

FIG. 2 DIAGRAM OF THETEST CIRCUIT FOR A TWO-POLE

EQUIPMENTON SINGLE-PHASEa.c.

—.. —

13

,’

1S 10027:2000

0,

.sA’

1<,.R,

1.,.IiR,D

“/

B

o,

0,, 0,,.

*sUppiy

To the neutral pointAdjustable resistorsAdjustable reactorsResistor for limiting tbe current in device DDevice for detection of a fault currentEquipment under testTemporary connection for prospective current calibrationTocurrent recording oscilloscopesTo voltage recording oscilloscopesVoltmeter

F[ci.3 DIAGRAM OF THETEST CIRCUIT FOR A THREE-POLE

EQIJILJMENTON THR~~-PHASE a.c.

The tests shall be made at the rated frequency of theapparatus as far as the testing station permits. If thisfrequency cannot be obtained. the test shall be made ata frequency between 45 and 62 Hz.

The power-factor shall be deemed to be the average ofthe cosines of the angles of phase displacement in allthe phases, and the power-factor of any phase shall notvary from the average by more than 25 percent of thataverage.

7.4.5 Behcwiour of the Apparatus During the Making

cIi7d Breaking Tesls

The apparatus shall perform during the above tests insLIcha manner as not to endanger an operator or cause

damage to adjacent equipment. There shall be nopermanent arding nor flashover.between poles or phases,and the fine wire fuse shall remain intact.

The apparatus shall remain mechanically operable andcontact weldilg, such as to prevent an operation usingnormal operating means,. is not permitted.

7.4.6 Conditivn of the Apparatus after the Making and

Breaking Tests

After the tests made in accordance with 7.4.2, theapparatus shah be capable, without maintenance, ofwithstanding a voltage equal to twice its rated insulationvoltage, applied as stated in 7.3.2.

It shall be demonstrated immediately after the test thatthe mechanictd switching device will close and opensatisfactorily tiuring a no-load close-open operation.

NOTE — A closing operationisconsideredsatisfactorywhennormal operation of the handle through its full stroke will closethe contacts sufficiently for the mechanical switching device

to be able to carry its rated current.

The contacts shall be in suitable condition to carry therated current. Where doubt exists, a tempemture risetest shall be carried out on the same apparatus; themeasured temperature rise shall not exceed by+rtore.thart10“Cthe values given in Table 1 or result in damage toadjacent parts.

7.5 Verification of the Rated Fused Short-CircuitCm-rent

7.5.1 Condition of the Apparatus for the Test

The apparatus shall be in the condition specified in 7.4.1and the fuse-wire stated by the manufacturer shall beused.

L

7.5.2 A first test shall be made on the apparatus, withthe mechanical switching device in the closed position,connected in series with a fuse-wire of the ratedmaximum current and rated breaking capacity deemedsuitable by the manufacturer for use with that equipment.A prospective current corresponding to the rated fusedshort-circuit current of the apparatus shall be applied.The current value is the rms value determined from theprospective current oscillogram.

A second test shall be made with new fuse-wire and thetest circuit made live with the mechanical switchingdevice open. The mechanical switching device shall beclosed onto a prospective current corresponding to therated fused short-circuit current of the apparatus.

_—

..”

14

The recovery test shall be maintained for at leastO.I second after interruption of the test current by thefuses,

DetaiIs of the fuse-wire used for the test shall be givenin the test report. The type test with the specified fuse-wire shall be deemed to cover the use of any other fuse\\/ire of rated cut rent not exceeding that of the fuse-wire

used for the test.

7.5.3 Test Circuit

The provisions of 7.4.3 shall apply,

The test circuit loads f,, and R, are not included for thefused short-circuit current test.

7.5,4 Test Quantities

The test shall be made at the rated frequency of theapparatus as far as the testing station permits. If thisfrequency cannot be obtained, the tests shall be made atfrequency between 45 and 62 Hz.

The average value of the power-frequi?ncy recoveryvoltage shall be equal to a value corresponding to notless than 110 percent and not more than 113 percent ofthe rated voltage stated by the manufacturer. The power-’factor of the circuit shall be in accordance with 3.3.6.The r.m.s. value of the a.c. component of the prospectivecurrent in any phase shall be equal to the specified valuowith a tolerance of +15percent.

-0

7.5.5 Behuviour of the Apparatus During the Rated

Fused Short-Circuit Current Tesl

The apparatus shall behave as specified in 7.4.5.

7.5.6 Condition ojthe Apparatus ajler the Rated Fused

Short-Circuit Current Test

After the test, the apparatus shall comply with therequirements of 7,4.6. The mechanical parts and theinsuIation of the apparatus shall be substantially in thesame condition as before.

7.6 Verification of the Mechanical Endurance

7.6.1 Operational Performance Test

7.6.1.1 Test value$ and conditions

The test values are stated in Table 4 and 4A and 3.3.8according to the utilization category.

IS 10027:2000

The time interval between Table 4 operating cycles withcurrent and without current and the sequential order ofthe tests shall be stated in the test report.

During each make-break operating.cycle, the equipmentneed only stay in the closed position for a period longenough to allow switching operation to be completedand to enable the current valueto be established and themoving parts of the equipment to come to rest. Aftereach operating cycle, the recovery voltage shall bemaintained for at least 0.05 s.

For a.c. the power-factor of the test circuit shall bedetermined in accordance with 7.4.4, The values shallbe in accordance with Table 4A and 3.3,8.

7.6.1.2

7.6.1.3

Test Circuit (see 7.4)

Transient recovery voltage

It isnot necessary to adjust the transient recovery voltage.

7,6.1.4 Behaviour of the equipment during the

operational performance test

The equipment shall perform during the above tests insuch a manner as not to endanger an operator or causedamage to adjacent equipment.

‘I’here shall be no permanent arcing or flash-overbetwee~ poles or between poles and frame and nomelting of the fuse in the detection circuit.

The equipment shall remain mechanically operable,Contact welding, such as to prevent an opening operationusing normal operating means, is not permitted,

Some wear on the mechanism and ccmtacts is allowedprovided that the equipment functions correctly.

7.6.1.5 .C~nditiov of the equipment ~fter the

operational performance test

It shall be demonstrated immediately after the test thatthe equipment will close and open satisfactorily duringa no-l~ad closelopen operation.

A closing operation is considered satisfactory whennormahoperation of the handle through its full strokewill close the contact efficiently for the equipment to beable to carry its rated operational current.

After the tests and without maintenance the equipmentshall comply with the requirements of 7.3.

15

1S 10027:2000

The contacts shall be in a suitable condition to can-ythertited operational current without maintenance and shallcolmply with theternperature-ris everificationof 7.2.

7.7 Durability (see3.3.9)

7.7.1 MechanicalD usability

The mechanical durability test (see 3.3.9.1) whererequired, is made in accordance with the appropriaterequirementsof 7.6.1exceptthat forequipmentsuitablefor isolation, the maximum value of leakage cornet shallnot exceed6 mA perpole for all utilization categories.

‘i-hetotal number of operating cycles shall be as declaredby Ihe Imanufacturer.

[f not stated by the manufacturer, the total number ofoperating cycles shall be taken from Table 4.

1.7.2 Electrical Durability

The electrical durability test (see 3.3.9.2) whererequired, is made in accordance with the appropriaterequirements of 7.6.1 except that for equipment suitablefor the total number of operating cycles shall be asdeclared by the manufacturer.

if not stated by the manufacturer, total number of

operating cycles shall be taken from Table 4.

7.8 Routine Tests

7.8.1 Mechanical Operational Test

A test shall be made to verify the correct mechanicaloperation of the equipment by five closing and openingoperations.

_-.7.8.2 Dielectric Test

The tests shall be carried’ out on dry and cleanequipment.

The value of the test voltage shall be in accordancewith 7.3.3.

The duration of each test maybe reduced to 1s.

The test voltage shall be applied as follows:a)

b)

c)

Between poles with the main contacts closed(with the contacts open if there is a shunt circuitbetween poles),Between poles and the frame of the equipmentwith the main contacts closed, andAcross the terminals of each pole with the maincontacts open.

The use of a metal foil, as specified in 7.3.1, is necessary.

ANNEX A(Clause 4.1)

INFORMATION TO BE GIVEN BY THE USER WH”EN CONDITIONS FX)ROPERATION IN SERVICE DIFFER FROM THE STANDARD

A-1 AMBl ENT AIR TEMPERATURE the equipment is to be installed near the sea.

A-1.1 The user shall state to the manufacturer the A-4 COND[T30NS OF INSTALLATIONexpected range of ambient air temperature if thistemperature is lower than – 5°Cor higher than + 40SC. A-4.1 The user shall call the manufacturer’s attention

A-2 ALTITUDE in case the equipment is to be fitted to a moving device,if its support is to be capable of assuming a sloping

A-2.1The user shall state to the manufacturer the altitude position either permanently or temporarily (equipmentof the place of installation if it is more than 2000 m. fitted aboard ships), or if it .is to be exposed in service

to abnormal shocks or vibrations.A-3 ATMOSPHERIC C0N131TIONS

A-3. 1 The user shall call the manufacturer’s attention ‘-5 CONNECTIONS WITH OTHER

in case the atmosphere in which the equipment is to be APPARATUS

installed may have arelative humidity greater than thevalues specified in 4.1.3 or contain an abnonnai amount A-5.1 The user shall inform the manufacturer of the

of’dust, acids, corrosive gases, etc. The same applies if type and dimensions of electrical connections with other

16

.—

apparatus in order to enable him to provide enclosuresand terlminals meeting the conditions of installation andtemperature rise prescribed by this standard, and also toenable him to provide space, where necessary, to spreadoutconductors within the enclosure.

IS 10027:2000

A-6 AUXILIARY CONTACTS

A-6.1 The user shall specify the number and type ofauxiliary contacts to be supplied to satisfy requirements,such as signaling interlocking, etc.

ANNEX B

(Clause 5.1.3.1)

EXAMPLES OF TERMINALS

--- ..—

ptional

I \A

Olroot Pro$wrettrrough screw head

,B

ptiond

A

c Optional

A

Irrdlreet lrrasaure through inl?rmsdizte pm

d — Fixed partII — Washer or clamping plate(’ — Anti-spread device

/1 — Conductor space

N() 1’1— Exmmplesshowlrhere do not prohibit theconductor being divided eitbiy side of the screw

Ycr[,ll /1,/’{11//1(1/\LI-LW-t!pc tcrmiod in which the conductor is clamped under the head o%ne or more screws. The clamping pressure may by applied directlyII! IiIQhcod of the screw or through an intermediate part, such as a washer, clamping plate or anti-spread device.

FIG.B 1 SCREWTERMINALS

17

1S 10027 :2OOO

D-D

%t of dwice Rrrt of d&ricewith cavity for terminal with cavitv for terminal

with direct pressure

Terminals with pressure plate

Terminals with indirect pressure

.1 — Fixed part11 — Body of the clamping unitl) — Conductor space

Pillar k,r-t~,ifl~lScrew-type twmitlal in which the conductor is inserted into a hole or cavity, where it is clamped under the shank of the screw or screws,Thc chul]ping pressure may be applied clirectly by the shank of the screw or through an intermediate part to which pressure is applied

by the shmli of the screw.

FIG,B2 PILLARTERMINALS

18

IS 10027:2000

B

ptional

l\ ~ \A

cOptional

D

\E \*

.( — Fixed part1{ — Washer or clamping plate(’ — Anti-spread device/) — Conductor spaceL— Stool

F!()[”I’—’l”hepart which re[ains the conchrctorin position may beef insulating material, provided the pressure necessary to clamp theconductors nottransmitted throughthe insulating material.

SCIC)J-[! pc terminal in which the conductor is clamped under one or two unit. The clamping pressure may by applied directly by a suitablyihi(pcd nutorthruugh an interlnediatc part, such as a washer, clamping plate oranti-spread deviee.

FIG. B3 STUD TERMINALS

ANNEX C(Ch.oes 3.1,5 .2.4,7,0.2 and 7.0.3)

DEGREE OF PROTECTION OF ENCLOSED EQUIPMENT

C-1 GENE-RAL

This annex provides information for specifying thedegree of protection for enclosed equipment hereinafterreferred to as equipment.

[t also specifies type tests to check the degree ofprotection on the various types of enclosures of enclosedequiptnent.

All enclosed equipment is intended to provide protectionas follows:

a) Protection of persons against contact with liveparts and against contact with moving parts (otherthan stnooth rotating shafts and the like) insidethe enclosure, and

b) Protection of the equipment inside the enclosureagainst the ingress of solid foreign objects, and/or

c) Protection of the equipment inside the enclosureagainst harmfid ingress of water.

This annex does not specifi the protection of equipmentagainst mechanical damage, risk of explosion or

conditions such as moisture (produced by example, bycondensation) corrosive vapours, fungus, or vermin.Internal barriers are considered for low-voltageswitchgear and controlgear as part of the enclosureprovided they meet at least the requirements of degreeIP2X.

A part or the whole mounted equipment may constitutea part or the whole of a barrier.

The basic tests and conditions are given in IS 12063but specific tests and interpretations apply to openingssuch as drain holes and ventilating openings, etc. Allopenings of enclosed equipment shall comply with the1PCode assigned to this equipment.

Drain holes are openings situated at the bottom of theenclosure and are intended to prevent the accumulationof water due to condensation andlor ingress of waterinto the enclosure. They shall comply with the basicrequirements for openings and not be smaller than2.5 mm in diameter.

C-2 DESIGNATION (CLASSIFICATIONSYSTEM)

The designation to indicate the degree of protection

19

1S 10027:2000

comists of the characteristics letters 1Pfollowed by twonumerals (the ‘characteristic numerals’) indicatingconformity with the conditions stated in Tables C 1 andC2 respectively. The first numeral indicates the degreeof protection described under items a) and b) and thesecond numeral the degree of protection described underitem c) of C-1.

Enclosures fitted with drain holes and/or ventilatingopenings shall satisfy the tests corresponding to th-eirrespective 1PCode.

The degree of pro’iection shall apply to all normalconditions of use.

Where the mounting of the equipment has an influenceon the degree of protection, this shall be indicated bythe manufacturer in his instructions for mounting or thelike.

C-2. 1 Single Characteristic Numeral

When it is required to indicate a class of protection byon1} one characteristic numeral, the omitted numeralshall be replaced by the letter X. For example 1PX5 orIP2X.

C-2.2 Supplementary Letters

11’required by the purchaser, supplier shall giveadditional information to be indicated by a supplementaryletter or letters in the classification. In such cases, theproduct standard shall state clearly the additional

conditions to be observed during tests for such aclassification.

The supplementary letters are as follows:

W — (Placed immediately after the secondcharacteristic numeral.) Equipment so designated issuitable for use under specific weather conditions andprovision has been made for additional protectivefeatures or procedures.

Both the specified weather conditions and the additionalfeatures or procedures shall be agreed betweenmanufacturer and user.

N — (Placed immediately after the secondcharacteristic numeral.) Equipment so designated issuitable for use in environments where the particle sizeand the nature of the dust requires additional featuresto be added (for exmaple for use in sawmills andquarries).

Both the specified conditions and thezxiditional featuresshall be agreed between manufacturer and user.

L — (Placed immediately after the first characteristicnumeral 2, 3 or 4.) Equipment so identified has beentested to provide protection against ingress of solidobjects exceeding 12.5 mm in diameter and againstcontact with live and moving parts by the standard testfinger (see Fig. C 1) in the case of first characteristicnumeral 2, or a 2.5 mm diameter test probe in the caseof characteristic numeral 3, or a 1 mm diameter testprobe in the case of first characteristic numeral 4.

Table C 1 Degrees of Protection Indicated by the First Characteristic Numeral

Iirst (’hxractcristic Short Description Degree of Protection Test Conditions,Nomcral and Suffix Definition Ref to

(see c-3)

1 Protected against solid Excludes solid objects C-7.1objects greater than exceeding 50 mm in dia50 mm and protects against contact

with live and moving parts bya large body surface such as ahand (but not against deliberateaccess)

21. Protected against solid Excludes solid objects C-7.2objects greater than exceeding 12.5 mm in12.5 mm and against diameter and protectscontact by standard against contact withtest finger live and moving parts

by a standard testfinger or similarobjects not exceeding80 mm in length

.? l’rotec~ed against solid Excludes solid objects c -7.3.1objects greater than exceeding 12.5 mm in

2,5 mm diameter or thickness——

20

IS 10027: 2“000

31/ Protected ugtrinst solid Excludes solid objects C- 7.3.2

objects greater than exceeding 12.5 mm in

12.5 mm and against diameter and protects

contact by 2.5 imm.probe against contact withlive and moving partsby a 2,5 mm diametertest probe not exceeding100 mm in length

4 Protected against solid Excludes solid objects C-7.4.1

objects greater thim exceeding 1.0 mm in

1.0 mm diameter or thickness

41. protects against solid Excludes solid objects C-7.4.2

objects greater than exceeding 12.5 mm in

12,5 mm and against diameter and protects

contact by 1.0 mm probe against contact withlive and moving partsby a 1,0 mm diametertest probe not exceeding100 mm in length

NOTE — The short description given in col 2 should not be used to specifi the form of protection.It should only be used as a brief

description.

5 *o,s~l~~

/~\le-li-ir--i

%

I Haodle> Stan olata

Saenorr c-c

@.

Parr 3

Lf,wur cl!tnerrsiotrs in m[lltmctres

Tolcmnccs on dimensions without ,peciiic tolerance:o ()

I(J 011 angles - 10”

,.~n linc~lr dinwnsit~nj.

()i ‘p 1025 mm:

- ().()5

()\ c1 -!; Inlll: +().2

bat.slix Ctrarrsfafauadgas(Example)

Parr 2 ‘&won back stie Pan 1

Material oftinger: forcxample heat-treated steel

Both joints of this finger may be bent through an angle of 90+ ‘~bat in one and the same direction only

Using the pin and groove solution is only one of the possibleapproaches in order to limit the bending angle to 90°, For this reasondimensions and tolerances of these details are not given in thetimwing, The actual design must ensure a 90° bending angle with s(j lo + I00 tolerance,

_. ..—

FIG. C 1 STANDARD TEST FINGIZR

21

lS 10027 :2000

C-2.3 Example of Designation

_.__l

Claacteristiclettersd j L1st characteristic numeral

(see Table C 1)

Supplementary letter

2nd characteristic numeral

(see Table C 2)

Equipment so designated provides protection againstcontacts with live and moving parts according toC-2.2 supplementary letter L, against ingress of solidobjects greater than 12.5 mm and against splashingwater.

C-3 DEGREE OF PROTECTION — FIRSTCHARACTERISITC NUMERAL

The first characteristic numeral indicates the degree ofprotection provided by the equipment both to the personsand to the equipment inside the enclosure.

Table C 1 gives, in co] 3, brief details of objects whichwill be excluded from the enclosure for each of thedegrees of protection represented’ by the firstcharacteristic numeral.

The term excluded implies that a part of the body or atool or a wire held-by a person, either will not enter-theenclosure or, if it is permitted to enter, that adequatedistance will be maintained between:it and the live parts

or dangerous moving parts (smooth rotating shafts andthe like are not considered dangerous).

NOTE— The definition for adequate distance is given inC-6.1.

Column 3 of Table C 1 also indicates the minimum size

Of solid foreign bodies which will be excluded.

NOTE — Equipment assigned a first characteristicnumeralof1 to 4 will exclude both regularly and irregularlyshaped solidobjects provided that three mutually perpendicular dimensionsof the object exceed the appropriate value in cd 3,

Compliance of enclosed equipment with a stated degree ofprotection implies that the encloiure will also comply with alllower degree of protection in Table C 1, In consequence, thetests establishing these degrees of protection need not be carriedout.

C-4 DEGREE OF PROTECTION — SECONDCHARACTERISTIC NUMERAL

The second characteristic numeral indicates the degreeof protection of enclosed equipment with respect toharmful ingress of water.

Table C 2 gives, in co] 3, details of the type of protectionprovided by the enclosure for each of the degree ofprotection represented by the second characteristicnumeral.

Compliance of an enclosure with a stated degree ofprotection implies that the enclosure will also complywith all lower degrees of protection in Table C2. Inconsequence, the tests establishing these degrees ofprotection need not necessarily be carried out.

—. ..—

Table C 2 Degrees of Protection Indicated by the Second Characteristic Numeral.First Characteristic Degree of Protection Test Conditions,

& -~umeml and Suffix Short Description Definition Ref to

(see C-3)

I Protected against Drippin~ water (vertically C-8.1dripping water falling drops) shall have

co harmful effecty Protected against Vertically dripping water C-8.2

dripping water when shall have no harmful effecttilted up to 15 when the enclosure is tilted

at any angle up to 15“fromits normal position.

3 Protected against Water falling as a spray at C-8.3spraying water an angle up to 60” from the

vertical shall have no harmfuleffect

4 Protected against Water splashed against the C-8.4splashing water enclosure from any direction

shall have no harmful effect5 Pmtectcd a~ainst Water projected by a nozzte Cr 8,5

waler jets against the enclosure from anydirection shall have no harmfuleffect— .. ..

N(Y1l — The short dcscriptiorrgivcl, i:: cd 2 shouldnot be used to speci~ the formof protection.It shouldonlybe used as a brief description

22

C-5 MARKING

The requirements for marking are specified in therelevant product standard, where applicable.

C-6 GENERAL REQUIREMENTS FOR TESTS

The tests in this annex are type tests.

AII tests shal be made with the equipment in anunenergized state.

The samples of equipment for each test shall be in aclean and new condition with all parts fitted andassembled as stated by the manufacturer for normal use.

Additional requirements, if any, my be given in therelevant product standard, concerning, for example

— number of samples; and— mounting and installation of samples.

[n the absence of such requirements, the manufacturerinstruction shall apply.

The interpretation of test results is given in C-7and C-8.

C-6.1 Adequate Distance

For the purpose of the following test clauses in thisannex, the term’ adequate distance’ has the followingmeaning: the test device (sphere, finger, wire, etc) doesnot touch live parts or moving parts other than non-dangerous parts such as smooth rotating shafis.

C -7 TEST FOR FIRST CHARACTERISTICNUMERAL

C-7.1 Test for First Numeral 1

The test is made with a rigid sphere of 50 mm indiameter applied against the opening(s) of theequiplnent with a force of 50 N f 10 percent.

The protection is satisfactory if the sphere does notpass though any opening and adequate distance ismaintained to pnts which are normally live in serviceor moving parts inside the enclosure.

C-7.2 Test for First Numeral 2

The test comprises two parts a) and b) which shall beeffected as follows:

a) Finger Test

The test is made with a metal test finger asshown in Fig. Cl. Both joints of this finger

b)

1s 1WJZ7 : Zuuu

may be bent through an angle of 90”with respectto the axis of the finger, but in one and the samedirection only. The finger is pushed withoutundue force (not mo’re than 10 N against anyopenings in the enclosure, and if it enters, it isplaced in the most unfavorable position withinthe equipment.

The protection is satisfactory if adequate distanceis maintained between the test finger and live ormoving parts inside the enclosure.

For this mechanical test, the internal moving partsmay be operated slowly, where this is possible.

A low-voltage supply (of not less than 40V) inseries with a suitable lamp may be connectedbetween the test finger and the live parts insidethe enclosure. Conducting parts covered onlywith.varnish or paint, or protected by oxidationor by a similar process, shall be covered with ametal foil electrically connected to those partswhich are normally live in service.

The protection is satisfactory if the lamp doesnot light.

Sphere Test

The test is made with a rigid sphere of 12,5mmin diameter applied to the openings of theenclosure with a force of 30 N t 10 percent.

The protection is satisfactory if the sphere doesnot pass through any opening and adequatedistance is maintained to live or moving partsinside the er,closure.

C-7.3 Test for First Numeral 3

C-7.3.1 Protection Against Ingress of Solid Foreign

Objects

The test is made with a straight rigid steel wire or rod of2.5 mm diameter applied-with a force of 3 N ~ 10 percent.The end of the wire or rad shall be free from burrs and atright angles to its length.

The protection is satisfactory if the wire or rod cannotenter the enclosure.

C-7.3.2 Protection Against Contacts with Live and

Moving Parts

The test is made with a straight rigid steel wire or rod of2.5 mm diameter and 100 mm long with a force of

23

IS 10027:2000

s N ~ 10 percent. The end of the wire or rod shall be according to Fig. C2, this corresponds to a fall in waterhemispherically shaped. level of 3 mm to 5 mm per minute).

The protection is satisfactory if adequate distance is The equipment under test is placed in its normal operatingmaintained with live and moving parts inside the position under the test apparatus, the base of which shallenclosure. be larger than that of the equipment under test. Except

for equipment designed for wall or ceiling mounting, theIn addition, the sphere test for first numeral 2 is to be support for the equipment under test should be smallereffected. than the base of the equipment.

C-7.4 Test for First Numerai 4 Equipment normally tixed to a wall or ceiling is fixed inits normal position of use to a wooden board having

C-7.4. 1 Protection Against [ngress of Solid Foreign dimensions which are equal to those of that surface ofol~iecl,v the equipment which is in contact with the wall or ceiling

when the equipment is mounted as in normal use.The test is made with a straight rigi ! steel wire of 1mmdiameter applied with a force of 1N f 10 percent. The The duration of the test shall be 10 min.

end of’the wire shall be free from mm and at rightangles to its length. C-8.2 Test for Second Numeral 2

The protection is satisfactory if the wire cannot enter The test apparatus.is the same as that specified in C-8.1the enclosure. and is adjusted to give the same rate of discharge,

C-7.4.2 Protection Against Contacts with Live and The equipment is tested for 2.5 min in each of four fixedA70vin~ Parts positions of tilt. These positions are 15“either side of

the vertical in two mutually perpendicular planes.The test is made with a straight rigid steel wire or i mmdiameter and 100 mm long with a force of IN t 10 The total -duration of-the test shall be 10 min.percent. The end of the wire shall be hemisphericallyshaped. C-8.3 Test for Second Numeral 3

The protection is satisfactory if adequate distanm is The test shall be made using test apparatus such as ismaintained with live and moving parts inside the shown in Fig. C3, provided that the dimensions and shapeenclosure. of the equipment to be tested are such that it will fit within

the radius of the oscillating tube as shown, Where thisIn addition the sphere test for first numeral 2 is to be condition cannot be fulfilled, a hand-held spray device,effected. as shown in Fig. C4, shall be used.

C-8 TEST FOR SECOND CHARACTERISTIC a) Conditions when using test apparatus as inN-UMERAL Fig. C-3.

The test shall be conducted with fresh water.

For the condition of the equipment after the tests(see C-8.5 ).

C-8.1 Test for Second Numeral 1

The test is made by means of an apparatus the principleof which is shown in Fig. C3; the rate of discharge shallbe reasonably uniform over the whole area of apparatusand shall produce a rainfall of between 3 mm and 5mm of water per minute (In the case of an apparatus

The water pressure is adjusted to give a delivery rateof at least 10 lhnin.

Water pressure — 80 kN/m2 (0.8 bar)approximately.

Method — The oscillating tube shall be providedwith spray holes over an arc of 60”either side of thecentre point and shall be fixed in a vertical position;the equipment tested is mounted on a turntable witha vertical axis and is kcated at approximately thecentre point of the semi-circle. The turntable is

-.

24

1S 10027:2000

~Ll~LltiilLJ al a conv~vlient ‘.peed so that ali parts ofthe cqNipnlcnt are \vette~l~i[~lingthetest.

‘i’i]ci~~illiillLilntest dLir:il!tlilshaiibe iOlmin.

Wiwn it is not pra:ticabic torotate the equipmentOIIaturntabie, itsi~aii be j!iaccd atthecentre of the\ellli-circie ar~dthetLibesi~al]be oscillated throughianangie ot’tie”cithersidc ofthe verticai positionala rate of approximately 600/s for 5 min. Theequipment is then turned tiwough a horizontal angieot90” and the test continued for a further period of5 min.

b) Conditions when using test apparatus as inFig. C4.

Tile counter balanced silieid shaii be in piace forthis test.

‘i-hewater pressure is alljusted to give a deliveryrate of iOihnin + O5 I/m in (pressure approximately

1

i I i

Ii 4— !-——.=L———— -

I i—~—I —18

I

II

80- iOOkN/m’ (0.8- 1.0 bar).

Tile test duration shaii be 1minimml of calculatedsurface area of the enciosurc (exciuding an>mounting surface) witil a minimum duration of5 min.

C-8.4 Test for Second Numera14

The conditions for deciding whether the apparatus ofFig. C3 or that of Fig. C4 shouid be used are the sameas those stated in C-8.3.

a) Using the apparatus of Fig. C3

Tile oscillating tube shail have hoies driiied overthe whole 180”of the semi-circie. The test duration,rate of oscillation and water pressure are as givenin C-8.3 (a).

Layers of sand and gravel to rogulata flow of watW,thooo Iayera being separatad by motaillc Qauza andbiotting paper

_!/.J-+-J-j!;([,. (’2 /\[![, : !,4 ‘ FURTI R VI:.R\l”icA’rmNOFPRO me rIoNAGAINST DRIPPINCWATER

25

—

1S 10027:2000

—1000 mu, +

. .. .—

““zCountorwoight

FIG.C3 APPARATUS FOR ‘rur;VERIFICAmONOF PROTECTIONAGAINST SPRAYINGAND SPLASHING WATER

/

Viewed according to arrow A (with shield removed)Dimensions in millimetres,

121 holes of (l 0.5:I lwle at the centre2 inoer cricles of 12 holes at 30° pitch

4 outer circles of 24 holes at 15° pitchMoving shield — AluminiumSpray nozzle — Brass

Frci. C4 HAND-HELD APPARATUSFORTHEVERIFICATIONOFPROTECTIONAGAINSTSPRAYINGAND

SPLASHINGWATER

26

IS 10027:2000

The support for the equipment under test shall beperforated so as to avoid acting as a baffle and theequipment shall be sprayed from every directionby oscillating the tube to the limit of its travel ineach direction.

b) I.Jsing lhe apparatus of Fig. C4.

Tbe counter balanced shield is removed from thespray nozzle and the equipment is sprayed from allpracticable direction.

“[he rate of water delivery and the spraying timeper unit area shall be as specified in C-8.3(b).

C-8.5 State of the Equipment after the Tesis

,\ fter testing in accordance with the appropriaterequirements of C-8.1 to C-8.4 the external surfacesshould be dried, and then the equipment shall beinspected f’oringress ofwatw.

the dimensions of the equipment, and it is not possibleto establish a general method suitable for all types ofenclosures.

For C-8. 1 to C-8.4 if any water has entered, it shall not:

– be sufficient to interfere with satisfactoryoperation.of the equipment;

— reach live parts or windings not designed tooperate when wet; and

— accumulate near the conduit hole (cable entry)or enter the cable.

Where the water ingress could raise doubts as to thefunctioning of the equipment a dielectric test withreduced value shall be effected (for example, a minimumof 50 percent of the dielectric test voltage). If theequipment is provided with drain holes it shall be provedby inspection that any water which enters does notaccumulate and that it drains away without doing any

Tl]c evaluation of’ harmful ingress of water depends on harm to the equipment,

ANNEX D(Clause 2.0)

LIST OF REFERRED INDIAN STANDARDS

ILTNo. Title

1S85 (Part 17) : 1979 El[ectrotechnicalvocabu-lary: Part 17 Switchgear andContro]gear (First revision)

~~g(j : 1993 Carriers and bases used inrewirable type electric fusesf’or voltages upto 650 V(ih;rd revision) “

Guide for uniform system ofmaking and identification ofconductors and apparatusterminals

11353: 1985

IS No.

12063:1987

13947

(Part 1): 1993

(Part 3): 1993

Title

Classification of degrees ofprotection provided byenclosures of electricalequipment

Low-voltage switchgear andcontrolgear:

General rules

Switches, disconnector,switch disconnectors andfuse-combination units

27

,,

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to yomoteharmonious development of the activities of standardization, marking and quality certification of goods andattending to connected matters in the country.

Copyright

BIS ‘has the copyright of all its publications. No part of.these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publication), BIS

Review of Indian Standards

Amendments are issued to standards as the neqd arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest ainendments or edition by referring to the latest issueof ‘E31SHandbook’ and’ Standards: Monthly Additions’.

This Indian Standard has “been developed from Dot: No.ET 07 ( 4030 ).

t,,

—-.

+Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

EHJR13AUOF INDIAN STANDARDS

Headquarters:

Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002 Telegrams: Manaksanstha

Telephones: 3230131,3233375,3239402 (Common to all ofllces)

Regional Ofllces: Telephone

Central :

Eastern :

Northern :

Southern :

Western :

Branches :

Manak Bhavan, 9 Bahadur Shah Zafu MargNEW DELHI 110002

1/14 C.1.T. Scheme VII M, V.I.P. Road, KankurgachiCALCU’ITA 700054

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C.I.T. Campus, IV Cross Road, CHENNAI 600113

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AHMADABAD. BANGALORE. BHOPAL. BHIJBANESHWAR.COIMBATORE. FARIDABAD. GHAZIABAD. GUWAHAT1.HYDERABAD. JAIPUR. KAIJPUR. LUCKNOW. NAGPUR.PATNA. PUNE. RAJKOT. THIRUVANANTHAPURAM.

3237617,3233841

{3378499,33785613378626,3379120

{

603843.602025

{2350216,23504422351519,2352315

{8329295,83278588327891,8327892

.—

Printedat Simco PrMing Press,Delhi