IS 10027: Composite Units of Air-break Switches and Rewirable Type Fuses for Voltages Not Exceeding 650 V a.c.

33 Pages·2000·2.6 MB·English

by  Bureau of Indian Standards

इंटरनेट मानक
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.
“जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ”
Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru
“The Right to Information, The Right to Live” “Step Out From the Old to the New”
IS 10027 (2000): Composite Units of Air-break Switches and
Rewirable Type Fuses for Voltages Not Exceeding 650 V a.c.
[ETD 7: Low Voltage Switchgear and Controlgear]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”

IS 10027:2000
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—..—
Indian Standard
tI
COMPOSITE UNITS OF AIR-BREAK SWITCHES
AND REWIRABLE TYPE FUSES FOR VOLTAGES
NOT EXCEEDING 650 V a.c.-— SPECIFICATION
(First Revision )
ICS 29.120.40; 29.120.50

@BIS 2000
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

I April 2000 Price Group 10
,,
!
Low Voltage Switchgear and Controlgear Sectional Committee, ET 07
FOREWORD
This Indian Standard (First Revision) was adopted bythe Bureau ofIndian Standards, after the draft finalized by
the Low Voltage Switchgear and Controlgear Sectional Committee had been approved by the Electrotechnical
Division Council.
Themajori~ oftheswitchesbeingmanufactured inIndiaaremetal-cladswitches. Switcheswithinsulatedenclosures
arealsoavailable inlargequantities. Theseswitchesandfise combinationunits,incorporating particularly rewirable
type fuses are being manufactured inthe small scalesector, intended for domestic and similar installations.
This standard has,therefore, beenbrought outprimarily tomeettherequirements ofthemanufacturer andtheusers
in respect of rewirable type switch-fuse units for current ratings not exceeding 100 A and of duty categories
AC-21Aand AC-21%. *
IS 13947(Part 3): 1993‘Specification forlow-voltage switchgear andcontrolgear: Part3Switches, disconnectors
and fuse combination units’-hasbeen published superseding IS4064 (Part 1and Part 2). It is,however, felt that
while revising 1S10027 incorporating requirements contained inIS 13947(Part 3),need for exclusively separate
standard is maintained in view of composite units and rewirable type fuses manufactured in small scale sector
intended for domestic and similar installations.
Inthe useofthis standard, references shallhavetobemadeto1S2086:1993 ‘Specification forcarriers andbases
used inrewirable type electric fuses for voltage upto650 V(third revision)’.
The object of this standard isto define:
a) The characteristics ofthe equipment;
b) The conditions with which the equipment shallcomply with reference to:
1) operation and behaviour innormal service;

2) operation and behaviour in caseofspecified abnormal conditions, for example, short-circuiu

3) dielectric properties;
c) The tests“intendedfor confirming that these conditions have been met and the methods to be adopted for
these tests; and
d) The data to bemarked onthe equipment.
For the purpose of deciding whether a particular requirement of this standard iscomplied with, the final value, +
observed orcalculated, expressing theresultofatest,shallberounded offinaccordance with IS2:1960 ‘Rulesfor .
rounding off numerical values (revise~’. The number of significant places retained in the rounded off value
should bethe same asthat ofthe specified value inthis standard.
lS 10027: 2000
Indian Standard
COMPOSITE UNITS OF AIR-BREAK SWITCHES
,\ND REWIRABLE TYPE FUSES FOR VOLTAGES
NOT EXCEEDING 650 V a.c. — SPECIFICATION
(First Revision)
I SCOPE mechanical switching deviceandoneormore fitsesina
_....x
composite unit, assembled by the manufacturer or in
1.I “Ibisstandard covers requirements for composite
accordance with his instructions,
u]]itsof air-break switches and rewirable type electric
fuseswith rated current not exceedirtg 100A intended
2.4 Switch-Fuse — A switch in which one or more
forsystem voltages not exceeding 650 Va,c,
poles have afuse in series inacomposite unit.
1.2 The switches incorporated inthe composite units
are intended for utilization category of AC-21A 2.5 Dependent Manual Operation (of a Mechanical
ffrequent operational) and AC-21B (infrequent Switching Device)— Anoperation solelybymeans of
operation), directly applied manual ener~j suchthat the speed and
force oftheoperation aredependent upon the action of
1.3 Therewirabletypetises, incorporatedincomposite the operator.
units, shall conform to the requirements laid down in
[S~086
2.6 Independent Manual Operation (ofaMechanical
Switching Device) — A stored energy operator where
NOTE—It shallhoweverberecognizedthatthisimpos’dsno
restriction on rewirable type fuse-combination of other the energy originates tlom manual power, stored and
categoriesofdutiesorcompositeunitsincorporatingcartridge releasedinonecontinuousoperation, suchthatthespeed
typefusesinwhichcasereference shallbemadetoIS 13947
andforceoftheoperation are independent ofthe action
([’art3).
ofthe operator,
NOTE — This standard shall cover only composite units
incorporating: 3 CHARACTERISTIC@ OF EQUIPMENT
a) Air-break ‘on’and ‘ofT switches of categoryAC-21A 3.1 Summary of Characteristics
andAC-2tBandforratedcurrentnotexceedkrg10OA,
The characteristics ofthe equipment shall be stated in

b) Rewirabletypeoffksesonly.and terms ofthe following asapplicable:

c) Enclosureofmetal-clad insulatedtypes
— Type of equipment (3.2)
2 REFERENCES AND DEFINITIONS - Rated quantities (see3.3)
- Utilization category (3.3.7)
2.0 The Indian Standards listed in Annex D are
— Dependent manual operation (see 2.5)
necessaryadjuncts tothis standard.
— Independent manual operation (see 2.6)
! 2.1 For the purpose of this standard, the following — Degree ofprotection (see Annex C)
, definitions in addition to those given in IS 1885
(Part 17) and IS 13947(Part 1)shall apply. 3.2 Type of Equipment
The equipment shallhave.the following details:
2.2 Switch (Mechanical) — A mechanical switching
devicecapableofmaking, carrying andbreakingcurrent a) Number of Poles — Either single pole with
under normal circuit conditions which may include neutral, double pole ortriple pole with neutral.
specitiedoperatingoverloadconditionsandalsocarrying
for aspecified time currents under specified abnormal b) Number oppositions — Theequipment shallhave
circuit conditions such,asthose of short-circuit. only two positions, that is ‘on’ and ‘of~.
NOTE—Aswitchmaybe capableofmaking,butnotbreaking
c) Kind of Current — The equipment shall be
short-circuitcurrents.
designed for use in single-phase or three-phase
2.3 Fuse-Combination Unit — A combination of a a,c. systems ofrated frequency of 50Hz.
1
IS 10027:2000
3.3 Rated Quantities In no caseshallthe maximumvalueofratedoperational
voltage exceedthat ofthe rated insulation voltage.
Rated qualities are assigned M indicated in 3.3.1
and3.3.2, butitisnot necessarytoestablishalltherated NOTE—Forequipmentnothavingaspecifiedratedinsulation
voitage,thehighestvalueoftheratedoperational voltage is
quantities listed.
considered tobetheratedinsulationvoitage.
3.3.1 Rated Voltages
3.3.1..3 Rated impulse withstand voltage (~~P)
Ali equipment isdefinedbythefollowingratedvoltages.
The peak value of art impulse voltage of prescribed
NOTE—Certaintypesof’equipmentmayhavemorethanone form ar,d polarity which the equipment is capable of
ratedvoltageormayhavearatedvoltagerange. withstanding without failureunder specified conditions
of test and to which the varue of the clearances are
3.3.1.1 Rated operational ‘;oitage (U.)
referred.
Arated operational voltage of anequipment isavahte
The rated impulse withstand voltage of an equipment
of voltage which combined with a rated operational
shallbeequalto orhigher thanthe value stated forthe
current, determinestheapp~kzttionoftheequipmentand
transient overvoltages occurring inthecircuit inwhich
towhich therelevant testsandtheutilization categories
are referred. theequipment isfitted.
Forsinglepoleequipment, theratedoperational voltage 3.3.2 Currents
isgeuerally stated asthe voltage acrossthepole.
Anequipment isdefined bythe following currents,
Formultiple equipment, itisgenerallystatedthevoltage
between phases. 3.3.2.1 Conventional free air thermal current (IJ
NOTES
I for certaindevicesandpWtiCLdaI’ applications.adifferent ‘The conventional free air thermal current is the
]methodof stating U.mayapply;this shouldbestatedin maximumvalueoftestcurrenttobeusedfortemperature
therelevantproductsttudard: risetestsofunenclosed equipment infreeairasgivenin
Table 1.
2 For nrrr!tipleequipmcn: ior useon polyphasecircuits, a
distinctionmaybemadebetween:
The value of the conventional free air thermal current
a) Equipment for use insystemwhere asingle faultto
shallbeat”leastequaltothemaximum valueoftherated
earthwillnotcausethefullphasetophasevoltageto
appear across a pole ( t hat isunearthed andneutral operational current (see 3.3.2.3) of the unenclosed
earthedsystems); equipment.
b) Equipment for use insystemwhere asingle faultto
earth wilIcauseto fullto phaseto phasevoltageto Freeairisunderstood tobeairundernormal conditions
appearacrossapole(thatisphaseearthedsystems); reasonably freefrom draughts andexternal radiation.
c) An equipment Imay lE assigned a number of
NOTES
combinationsof ratedoperationalvoltagesandrated
I Thecurrentisnotaratingandisnotmandatorilymarked
operationalcurrent!orpowersfordifferentdutiesand
ontheequipment.
utilization categories,
d) An equipment may bc assigned a number of rated 2 Anunenclosedequipmentisanequipmentsupplied.bythe
operationalvoltagesandassociatedmakingandbraking manufacturer without an enciosure or an equipment
capacities for ciiflcreat duties and utilizations suppiied-bythemanufacturerwith anintegrai enclosure
categories; :~nd whichisnotnormaliyintendedto bethesoleequipment .,
protectiveenciosure.
e) Attention is drawn to the fact that the operational
voltagesmaydifferfromtheworkingvoltages ofan
3.3.2.2 Conventional enclosed thermal current (1J
equipmenr.
Theconventional enclosed thermal current isthe value
3.3.1.2 Rated insulation voltage (U.)
ofcurrent statedbythemanufacturer tobeused forthe
Theratedinsulationvoltageofanequipmentisthevalue temperaturerise tests of the equipment when mounted
ofvoltagetowhich dielectrictestsvoltageandcreepage in a specified enclosure, Such tests shall be in
distances are referred. accordancewith 5.3andaremandatory iftheequipment
L
IS 10027:2000
Table’1 Temperature Rise Limits If the equipment is normally intended for use in
(Cluuxes 3.3.2.1,5.3,7.2.2, and7.4.6) unspecified enclosures, the test isnot mandatory ifthe
test for conventional free air thermal current (IJ has
SI Type of’Nlaterial and Description Temperature Rise been made. In this case, the manufacturer shall be
No ofPart Limit
prepared to give guidance on the value of enclosed
(1) (2) (3)
thermal current orthe derating factor.
i) Conlact parts(mainandauxiliarycontacts):
a) Copper: NOTES
\:nintcrruptedduty 45k 1 ‘t’hiscurrentisnotaratir.gandisnotmandatorily marked
b) Silverorsilver-faced(seeNote I) (seeNote2) ontheequipment.
c) Allothermetalsorsinteredmetals (seeNote3),
ii) Bareconductors (seeNote2) 2 The conventional enclosed thermal current value may be
iii) Metallic parlsactingassprings (seeNote4) forunventilatedequipmentinwhichcasetheenclosureused
iv) Metallic partsincontactwith (seeNote5) forthetestshallbeofthesizestatedbythemanufacturer
insulatingmaterials as being the smallest that is applicable in service.
~) Terminalsforexternalinsulated 70K Alternatively,thevaluemaybeforaventilatedequipment
connections (seeNote6) accordingtothemanufacturer’sdata.
vi) Manualoperatingmeans(handles,Icvers,wheels,etc): 3 Anenclosedequipmentisanequipmentnormallyintended
a) Partsoflme~al 15K for use with a specified type and size of enclosure or
b) Partsofinsulatingmaterial 25K intendedforusewithmorethanonetypeofenclosure.
NorEs
1 Theexpression‘siLver-faced’includessolidsilverinserta 3.3.2.3 Rated operational currents (Ic) or rated
aswellaselectrolyticallydepositedsilver,providedthat, operational powers
inthelattercase,thetemperatureriserequirementof7.4.6
aresatisfied. Aratedoperational current ofanequipment isstated by
Contactsfacedwithothermaterials,thecontactresistance
the manufacturer and takes into account the rated
01which is not significantly altered by oxidation, are
operational voltage (see 3.3,1.1), the rated frequency
treatedassilver-facedcontacts,
(see 3.3.3), theratedduty,theutilization categories and
2 Limitedsolelybythenecessityofnotcausinganydamage thetype ofprotective enclosure, ifappropriate.
toadjacentparts.
In the case of equipment for direct switching of
3 Tobespeciiied accordingtothepropertiesofthemetals
individual motors, the indication of arated operational
used and limited by the necessity of not causing arty
damagetoadjacentparts. current may be replaced or supplemented by an
indication of the maximum rated power output, at the
4 The resulting temperature shall n ot reach avalue such rated operational voltage considered, of the motor for
thatthe elasticity ofthematerial isimpaired. Forpure
copper, this implies atotal kmpcra t ure not exceeding whichtheequipmentisintended. Themanufacturer shail
75°c. be prepared to state the relationship assumed between
theoperationalcurrentandtheoperational power, ifany.
5 Lin]itd solelybythe;mccssi!yolnot causinganydamage
10insulatingmaterials. Forthepurpose ofthisstandard, thepreferred vaiues of
rated current shallbe 16,32, 63 and 100A.
(1 ‘[!:ctelnperatureriselimit0171JKisavaluebasedonthe
,.,~:licntional testof7.2.2. Anequipmentusedortested
LIndeirnstalIationconditions Inayhaveconnectionsthe 3.3.2.4 Rated uninterrupted current (Iu)
typc,natureanddispositionot’whichwillnotbethesame
asthoseadoptedforthetest;adifferenttemperaturerise The rated uninterrupted current of an equipment is a
ofterminalmayresultanditmayberejectedoraccepted. value ofcurrent, statedbythe manufacturer, which the
equipment can carry inuninterrupted duty.
isdescribed asenclosedequipment inthemanufacturer’s
catalogues and normally intended for use with one or 3.3.3 Rated Frequency
tmoreenclosures ofspecified type amisize(seeNote2).
The supply frequency for which an equipment is
designed atrdto which the other characteristic vaiues
The vaiue ofthe conventional enciosed thermal current
correspond.
shaiibeat ieastequaitothemaximum vaiueoftherated
opet-ational current (see 3.3.2.3) of the enclosed
For the purpose of this standard, the rated frequency
equipment,
shailbe 50 Hz.
3
IS 10027:2000
3.3.4 Ruted Muking CcipacI& Theratedmakingcapacityisstatedbyreferencetotherated
operational voltage andrdtedoperational current andto
theutilizationcategoryaccordingtoTable2.
The rated making capacity of’an equ-ipmentisa value
of current, stated by the manufacturer, which the 3.3.4.1 Fora.c.the making current isexpressed bythe
equipment can satisfactorily make under specified r.m.s. value ofthe periodic component ofthe current.
making conditions.
3.3.5 Rated Breaking Capaci@
The making conditions which shall bespecified are:
— the applied voltage The rated breaking capacity ofanequipment isavalue
— the characteristics of thetest circuit of current, stated by the manufacturer, which the ..—
equipment can satisfactorily break, under specified
The rated making capacity isstated by reference to be
breaking conditions.
rated operational voltage and rated operational current,
according to the relevant product standard.
Thebreaking conditions which shall bespecified are:
NOTES — the characteristics ofthe test circuit
I I-’ora.c., rated making capacity isexpressed bythe r,m.s, — the power frequency recovery voltase
vah]cofthesymmetricalcrrmporumtoftheccrrren~assumed
tobecrmstant.
Theratedbreaking capacity isstatedbyreference tothe
~ Fora.c.thepeakvalueofthecurrentduringthefirsthalf- rated operational voltage and rated operational current.
CYCkS foIlowingthe closing ofthe maincontacts ofthe
cquipmeotmaybeappreciablygreaterthanthepeakvalue Anequipment shallbecapable ofbreaking anyvalue of
of the current under steady state condition used in the
current up to anincluding itsrated breaking capacity.
determinationofmakingcapa~ity,dependingonthepower-
i’hctorof the circuit andthe instantorrthe voltagewave
lvhenclosingoccurs. NOTES
3 Anequipment should becapableofclosingon acurrent 1 Aswitchingdevicemayhavemorethanoneratedbreaking
havingthea.c.componentequaltothatwhichdefinesits capacity,eachcorrespondingtoanoperationalvoltageand
ratedmakingcapacity,whateverthevalueoftheinherent autilizationcategory(AC-2IAorAC-21Binthiscase).
d.c.component,withinthelimitsresultingfromthepower-
Factorsindicated intheIndianStandard.
Table 2 Verification of Rated Making and Breaking Capacities (see 7.4) Conditions for
Making 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 of
Category Current IJIe Ujua Cosa Operating Cycles
.AC-2IA Allvalues 1.5 1.05 0,95 5
andAC-21B
—.
iiIhcr-c
1= Makingcurrent
IL = Breakin: c~lrreat
1, = Ratedoperationalcurrent
1’ = Appliedvoltage
[! = Ratedoperational voltage
1 = Powerfrequencyrecoveryv(}lP.ige
4
lS 10027 :2000
2 Fora.c, therated breakingcapaeityisexpressed bytherms example, to disconnectors normally only operated to
valueot’symmetrical componentot’thecurrent.
provide isolation for maintenance work or switching
devices where the fuselink blade forms the moving
Therated breaking capacity isstatedbyreference tothe
contact.
rated operational voltage and rated voltage current and
to the utilization categories according to Table 3
Table 3 Utilization Categories
and 3.3.5.
(Clauses 3.3.5 and 3.3.7)
3.3.6 Ra{ed Fused Shor~-Civcuit Current
Nature of Frequent Infrequent Typical
Current Operation Operation Applications
The rated fused short-circuit current of the equipment -.. —
is the value of prospective current, stated by the Alternating AC-21A AC-21B Switchingof
current resistiveloads
manufacturer, which the equipment can satisfactorily
including
withstand untilthe fuse blows. moderate
overloads
The value of rated fused short-circuit current shall
The utilization categories referred to in Table 2 and 3
beasfollows:
do not apply to an equipment normally used to start,
accelerateand/orstopindividualmotors. Theutilization
Rated Current Fused Short-Circuit
categories for such an equipment are dealt with in
(A) Current (A) (r.m.s.)
Annex AofIS 13947(Part 3).
16 2000
32 4000
3.3.8 Operational Performance
63 4000
100 4000
Tests concerning the verification of the operational
performance ofanequipment areintendedtoveri& that
The standard power factor shall be 0.8 and the ratio theequipmentiscapableofmakingandbreakingwithout
between the peak and the r.m.s.value of current shall failure, the currents flowing in itsmain circuit for the
be 1.47. intended use.
A power factor ofO.4 may be agreed to between the The number of operating cycles and the test circuit
manufacturer and the user for special application, if parameters forthe operational performance test forthe
necessary. various utilization categories are given in Tables
4 and4A.

3.3.7 Utilization Category
Thetest conditions are specified in 7.6.1.
The utilization categories define the intended
3.3.9 Durability
applications and aregiven inTable 3.
NOTE — The term durability has been chosen instead of
Eachutilization category ischaracterized bythe values enduranceinordertoexpresstheexpectancyofthenumberof
of the currcmtand vokages, expressed as multiples of operating cycles which can be performed by the equipment
before repair or replacement of parts, Moreover the term
the rated operational current and the rated operational
endurance is also commonly used to cover operational
voltage, as well asthe power-factor or time-constants
performanceasdefinedin 3.3.8anditwasdeemed necessory
oft!lecircuit. The conditions for making andbreaking nottousethetermendurarrceinthisstandardinordertoavoid
given in Table 2. Correspond in principle to the confusionbetweenthetwoconcepts,
applications listed inTable 3.
3.3.9.1 Mechanical durability
The designation of utilization categories is completed With respect to its~esistance to mechanical wear, an
bythe suffixA or Baccording towhether the intended equipment is characterized by the number, -stated in
applications require frequent or infrequent operations 7.7.1, ofthisstandard ofno-load operating cycles (that
(see Table 3). iswithout current at the main contacts) which can be
effectedbeforeitbecomesnecessarytoserviceorreplace
Utilization categories with suffix Bare appropriate for any mechanical parts; however normal maintenance
devices which, due to design or application, are only according to the manufacturer’s instructions may be
intendedfor infrequent operation. Thiscould apply,for permitted for equipment designed to bemaintained
5

,’