UL1022

STANDARDFORSAFETY

LineIsolationMonitors

MARCH27,2025-UL1022

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ULStandardforSafetyforLineIsolationMonitors,UL1022SixthEdition,DatedMarch27,2025

SUMMARYOFTOPICS

ThisnewSixthEditionofANSI/UL1022datedMarch27,2025incorporateseditorialupdatesfromtheFebruary21,2025proposal(s)bulletin.Othereditorialupdatesincluderenumberingandreformattingtoalignwithcurrentstyle.

TherevisedrequirementsaresubstantiallyinaccordancewithProposal(s)onthissubjectdatedFebruary21,2025.

Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmittedinanyformbyanymeans,electronic,mechanicalphotocopying,recording,orotherwisewithoutpriorpermissionofULSEInc.(ULSE).

ULSEprovidesthisStandard"asis"withoutwarrantyofanykind,eitherexpressedorimplied,includingbutnotlimitedto,theimpliedwarrantiesofmerchantabilityorfitnessforanypurpose.

InnoeventwillULSEbeliableforanyspecial,incidental,consequential,indirectorsimilardamages,includinglossofprofits,lostsavings,lossofdata,oranyotherdamagesarisingoutoftheuseofortheinabilitytousethisStandard,evenifULSEoranauthorizedULSErepresentativehasbeenadvisedofthepossibilityofsuchdamage.InnoeventshallULSE'sliabilityforanydamageeverexceedthepricepaidforthisStandard,regardlessoftheformoftheclaim.

UsersoftheelectronicversionsofUL'sStandardsforSafetyagreetodefend,indemnify,andholdULSEharmlessfromandagainstanyloss,expense,liability,damage,claim,orjudgment(includingreasonableattorney'sfees)resultingfromanyerrorordeviationintroducedwhilepurchaserisstoringanelectronicStandardonthepurchaser'scomputersystem.

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MARCH27,2025

ANSI/UL1022-2025

1

UL1022

StandardforLineIsolationMonitors

FirstEdition–March,1973SecondEdition–July,1979ThirdEdition–March,1994FourthEdition–June,1998FifthEdition–April,2012

SixthEditionMarch27,2025

ThisANSI/ULStandardforSafetyconsistsoftheSixthEdition.

ThemostrecentdesignationofANSI/UL1022asanAmericanNationalStandard(ANSI)occurredonMarch27,2025.ANSIapprovalforastandarddoesnotincludetheCoverPage,TransmittalPages,andTitlePage.

CommentsorproposalsforrevisionsonanypartoftheStandardmaybesubmittedtoULSEatanytime.ProposalsshouldbesubmittedviaaProposalRequestintheCollaborativeStandardsDevelopmentSystem(CSDS)at.

OurStandardsforSafetyarecopyrightedbyULSEInc.NeitheraprintednorelectroniccopyofaStandardshouldbealteredinanyway.AllofourStandardsandallcopyrights,ownerships,andrightsregardingthoseStandardsshallremainthesoleandexclusivepropertyofULSEInc.

?2025ULSEInc.Allrightsreserved.

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CONTENTS

INTRODUCTION

Scope 5

Components 5

UnitsofMeasurement 5

ReferencedPublications 6

Glossary 6

InstructionsandDrawings 7

CONSTRUCTION

Enclosure 7

General 7

Castmetalenclosures 7

Sheetmetalenclosures 8

Nonmetallicenclosures 9

Ventilatingopenings. 10

Covers 10

Glasspanels 11

ElectricShock 11

CorrosionProtection 12

Field-WiringSystemConnections 12

General 12

Equipmentgroundingconnection 13

InternalWiring 13

General 13

Wireways 14

Splices 14

Barriers 14

Bushings 14

Strainrelief 15

BondingforGrounding 15

Components 16

Current-carryingparts 16

Insulatingmaterial 16

Lampholdersandlamps 17

Meters 17

Printed-wiringboards 18

Switches 18

Protectivedevices 18

Alarmsilencingmeans 18

Audiblesignalingappliance 18

Mountingofcomponents 18

Operatingcomponents 19

Spacings 19

ServicingandMaintenance 20

PERFORMANCE

General 21

NormalOperationTest 21

SamplingCircuitSupervisionTest 22

PowerInputTest 23

LeakageCurrentMeasurementsTest 23

OvervoltageandUndervoltageTest 26

Voltageoperation 26

Undervoltageoperation 26

JarringTest 27

TemperatureTest 27

OverloadTest 30

Monitor 30

Separatelyenergizedcircuits 30

EnduranceTest 30

Monitor 30

Devicesandseparatelyenergizedcircuits 31

VariableAmbientTemperatureTest 31

HumidityTest 31

ElectricShockCurrentTest 31

TransientTests 35

General 35

Externally-inducedtransients 35

Internally-inducedtransients 35

DielectricVoltage-WithstandTest 35

ComponentFailureTest 36

AbnormalOperationTest 36

TestSwitchOperationTest 37

MANUFACTURINGANDPRODUCTIONTESTS

General 37

Production-LineLeakageCurrentMeasurementsTest 37

Production-LineDielectricVoltage-WithstandTests 37

MARKING

General 38

Supplementary 39

Installationdrawing 39

Operatinginstructions 39

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INTRODUCTION

Scope

Theserequirementscoverdynamiclineisolationmonitorsandrelatedsupplementaryindicatingunitsforsupervisingisolatedpower-supplycircuitsinpatientcareareasofhealthcarefacilities,includinginhalation-anesthetizinglocationsinaccordancewiththeNationalElectricalCode,NFPA70.

Thedetectorsandsupplementaryindicatingunitsareintendedtobe:

Includedaspartofanisolatedpower-supplycenterforpatientcarelocationsofhealthcarefacilities;and

InstalledinanOther-Than-Hazardous(Classified)LocationofahealthcarefacilityasdefinedbytheNationalElectricalCode,NFPA70.

TheserequirementsdonotcovergroundfaultcircuitinterruptersforuseongroundedalternatingcurrentsystemsinaccordancewiththeNationalElectricalCode,NFPA70.

Components

AcomponentofaproductcoveredbythisStandardshall:

ComplywiththerequirementsforthatcomponentasspecifiedinthisStandard;

Beusedinaccordancewithitsratings(s)establishedfortheintendedconditionsofuse;and

Beusedwithinitsestablisheduselimitationsorconditionsofacceptability.

AcomponentofaproductcoveredbythisStandardisnotrequiredtocomplywithaspecificcomponentrequirementthat:

InvolvesafeatureorcharacteristicnotrequiredintheapplicationofthecomponentintheproductcoveredbythisStandard;or

IssupersededbyarequirementinthisStandard;or

Isseparatelyevaluatedwhenformingpartofanothercomponent,providedthecomponentisusedinaccordancewithitsestablishedratingsandlimitations.

Specificcomponentsareincompleteinconstructionfeaturesorrestrictedinperformancecapabilities.Suchcomponentsareintendedforuseonlyunderlimitedconditions,suchascertaintemperaturesnotexceedingspecifiedlimits,andshallbeusedonlyunderthosespecificconditions.

Acomponentthatisalsointendedtoperformotherfunctionssuchasovercurrentprotection,ground-faultcircuit-interruption,surgesuppression,anyothersimilarfunctions,oranycombinationthereof,shallcomplyadditionallywiththerequirementsoftheapplicablestandard(s)thatcoverdevicesthatprovidethosefunctions.

UnitsofMeasurement

Valuesstatedwithoutparenthesesaretherequirement.Valuesinparenthesesareexplanatoryorapproximateinformation.

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ReferencedPublications

AnyundatedreferencetoacodeorstandardappearingintherequirementsofthisStandardshallbeinterpretedasreferringtothelatesteditionofthatcodeorstandard.

ThefollowingpublicationsarereferencedinthisStandard:

ASTME230/E230M,StandardSpecificationforTemperature-ElectromotiveForce(emf)TablesforStandardizedThermocouples

NFPA70,NationalElectricalCode

Glossary

ForthepurposeofthisStandardthefollowingdefinitionsapply.

FAULTIMPEDANCE–Animpedancethatmayconsistofbalancedorunbalancedresistive,capacitive-reactive,orcombinedresistive-capacitive-reactiveloadsconnectedtoeitherorbothisolatedconductors.See

Figure20.1

forloadconfigurations.

HAZARDCURRENT–Thetestcurrentthatwouldflowthroughalowimpedanceconnectedbetweeneitherisolatedconductorandground.Hazardcurrentincludes:

TOTALHAZARDCURRENT(THC)–Hazardcurrentwithalldevicesconnected,includinglineisolationmonitors;

MONITORHAZARDCURRENT(MHC)–Thatportionofthetotalhazardcurrentcontributedonlybythemonitorandremoteindicators;and

FAULTHAZARDCURRENT(FHC)–Thatportionofthetotalhazardcurrentresultingwhenalldevices,exceptthelineisolationmonitors,areconnected.

LINEISOLATIONMONITOR(LIM)–Atestinstrumentdesignedtocontinuallycheckthebalancedandunbalancedimpedancesfromeachsideofanisolatedcircuittogroundandequippedwithabuilt-intestcircuittoexerciseanalarmwithoutaddingtothehazardcurrent.Itinitiatesavisualandanaudibleindicationwhenthehazardcurrentexceedsapresetthresholdlevel.

REMOTEINDICATOR–Deviceconnectedremotelytothelineisolationmonitorwhichprovidesanyoneofthefollowingfunctions;visualsignal,audiblesignal,orbothvisualandaudiblesignalswhichsupplementthesignalprovidedbythelineisolationmonitor.

VOLTAGECLASSIFICATION–

HIGH-VOLTAGE–Acircuitclassifiedashigh-voltageisonehavingcircuitcharacteristicsinexcessofthoseofalow-voltagecircuit.

LOW-VOLTAGE–Acircuitclassifiedaslow-voltageisoneinvolvingapotentialofnotmorethan30voltsalternatingcurrent(42.4peak)ordirectcurrent,andsuppliedbyaprimarybatteryorbyaClass2transformerorbyacombinationoftransformerandfixedimpedancewhich,asaunit,complieswithalltheperformancerequirementsforaClass2transformer.

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InstructionsandDrawings

Acopyoftheoperatingandinstallationinstructionsandrelatedschematic,wiringdiagrams,andinstallationdrawingsistobefurnishedwiththesamplesubmittedforinvestigationtobeusedasaguideintheexaminationandtestoftheunit,andforthispurposeisnotrequiredtobeinfinalprintedform.

Theinstructionsanddrawingsshallincludesuchdirectionsandinformationasdeemedbythemanufacturertobeadequateforattainingproperinstallationandmaintenance.Adescriptionofthecircuitfunctionsshallbeprovidedtofacilitateunderstandingofthesystemoperation.

CONSTRUCTION

Enclosure

General

Alineisolationmonitorenclosureshallbeformedandassembledsothatithasthestrengthandrigidityrequiredtoresisttheabusestowhichitissubjectedwithouttotalorpartialcollapseresultinginreductionofspacings,looseningordisplacementofparts,orotherseriousdefects.

Allelectricalpartsofalineisolationmonitorshallbeenclosedtoprovideprotectionagainstcontactwithuninsulatedliveparts.

Acompartmentenclosingelectricalpartsshallnotbeopentothefloororothersupportonwhichtheunitrests.

Anenclosureforalineisolationmonitorshallhaveprovisionforconnectionofmetal-cladcableorconduit,oranonmetallic-enclosedwiringsystem(forexample,nonmetallicsheathedcable)acceptablefortheapplicationundertheprovisionsofNFPA70.

ExceptionNo.1:Anenclosurewithoutprovisionfortheconnectionofmetal-cladcable,conduit,oranonmetallic-enclosedwiringsystemisnotprohibitedfrombeingusedwhentherearefurnishedwithit,definiteinstructionsindicatingthesection(s)oftheunitintendedtobedrilledinthefieldfortheconnection(s).

ExceptionNo.2:Alineisolationmonitorwhichisintendedtobeinstalledinanoverallenclosurewithotherequipmentisnotrequiredtohaveprovisionforconnectionofmetal-cladcableorconduit.

Alineisolationmonitorwhichistobeinstalledinanoverallenclosureshallnotbeexposedtoanambienttemperatureexceeding50°C(122°F).

Anenclosureshallhavemeansformountingwhichshallbeaccessiblewithoutdisassemblinganyoperatingpartoftheunit.Removalofacompletelyassembledpanelorprintedwiringboardtomounttheenclosureisnotconsideredtobedisassemblyofanoperatingpart.

Anenclosureforalineisolationmonitorwhichisintendedforrecessed(flush)mountingshallnothaveanyopeningsotherthanconduithubs,knockouts,oropeningsformountingscrews.

Castmetalenclosures

Thethicknessofcastmetalforanenclosureshallbeasindicatedin

Table7.1

,exceptthatcastmetalhavingathickness1/32inch(0.8mm)lessthanthatindicatedinthe

Table7.1

isnotprohibitedfrom

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beingusedwhenthesurfaceunderconsiderationiscurved,ribbed,orotherwisereinforced,orwhentheshapeand/orsizeofthesurfaceissuchthatequivalentmechanicalstrengthisprovided.

Whenthreadsfortheconnectionofconduitaretappedallthewaythroughaholeinanenclosurewall,orwhenanequivalentconstructionisemployed,thereshallnotbelessthan3-1/2normorethan5threadsinthemetal,andtheconstructionshallbesuchthatastandardconduitbushingiscapableofbeingproperlyattached.

Whenthreadsfortheconnectionofconduitaretappedpartwaythroughaholeinanenclosurewall,thereshallbeatleast3-1/2fullthreadsinthemetal,andasmooth,roundedinletholefortheconductors,whichshallaffordprotectiontotheconductorsequivalenttothatprovidedbyastandardconduitbushing.

Table7.1

Cast-MetalEnclosures

Use,ordimensionsofareainvolved

Minimumthickness

Die-castmetal

inches (mm)

Castmetalofotherthanthedie-casttype

inches (mm)

Areaof24squareinches(154cm2)orlessandhaving

1/16

(1.6)

1/8

(3.2)

nodimensiongreaterthan6inches(152mm)

Areagreaterthan24squareinchesorhavingany

3/32

(2.4)

1/8

(3.2)

dimensiongreaterthan6inches

Atathreadedconduithole

1/4

(6.4)

1/4

(6.4)

Atanunthreadedconduithole

1/8

(3.2)

1/8

(3.2)

Sheetmetalenclosures

Thethicknessofsheetmetalemployedfortheenclosureofalineisolationmonitorshallnotbelessthanindicatedin

Table7.2

,exceptthatsheetmetaloftwogagesizeslesserthicknessisnotprohibitedfrombeingusedwhenthesurfaceunderconsiderationiscurved,ribbed,orotherwisereinforced,orwhentheshapeand/orsizeofthesurfaceissuchthatadequatemechanicalstrengthisprovided.

Atanypointwhereconduitormetal-cladcableistobeattached,sheetmetalshallbeofsuchthicknessorshallbeformedorreinforcedsothatithasthestiffnessatleastequivalenttothatofuncoatedflatsheetsteelhavingaminimumthicknessof0.053inch(1.35mm)(No.16MSG).

Aplateorplugforanunusedconduitopeningorotherholeintheenclosureshallhaveathicknessnotlessthan:

0.014inch(0.36mm)forsteelor0.019inch(0.48mm)fornonferrousmetalforaholehaving1/4inch(6.4mm)maximumdimensionor

0.027inch(0.66mm)steelor0.032inch(0.81mm)nonferrousmetalforaholehavinga1-3/8inch(34.9mm)maximumdimension.

Aclosureforalargerholeshallhaveathicknessequaltothatrequiredfortheenclosureofthedeviceorastandardknockoutsealshallbeused.Suchplatesorplugsshallbesecurelymounted.

Aknockoutinasheetmetalenclosureshallbereliablysecuredbutshallbecapableofbeingremovedwithoutunduedeformationoftheenclosure.

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Aknockoutshallbeprovidedwithaflatsurroundingsurfaceadequateforproperseatingofaconduitbushing,andshallbelocatedsothatinstallationofabushingatanyknockoutlikelytobeusedduringinstallationwillnotresultinspacingsbetweenuninsulatedlivepartsandthebushingoflessthanthoseindicatedinSpacings,Section

14

.

Table7.2

SheetMetalEnclosures

Maximumenclosuredimensions

Minimumthicknessofsheetmetal

Anylineardimension

inches (mm)

Areaofanysurfacein2 (cm2)

Steel

Copper,brass,oraluminum

inches (mm)

Zinc-coated

inches (mm)

Uncoated

inches (mm)

12

(305)

90

(581)

0.034

(0.86)

0.032

(0.81)

0.045

(1.14)

[20]a

[20]a

[16]a

24

(610)

360

(2322)

0.045

(1.14)

0.042

(1.07)

0.058

(1.47)

[18]

[18]

[14]

48

(1219)

1200

(7742)

0.056

(1.42)

0.053

(1.35)

0.075

(1.91)

[16]

[16]

[12]

60

(1524)

1500

(9678)

0.070

(1.78)

0.067

(1.70)

0.095

(2.41)

[14]

[14]

[10]

Over60

(1524)

Over1500

(9678)

0.097

(2.46)

0.093

(2.36)

0.122

(3.10)

[12]

[12]

[8]

aThefiguresinbracketsaretheGalvanizedSheetGagenumbers(forzinc-coatedsteel),theManufacturers'StandardGagenumbers(foruncoatedsteel),andtheAmericanWireGage(B&S)numbers(foranonferrousmetal)whichprovidetherequired

minimumthicknessofmetal.

Nonmetallicenclosures

Nonmetallicmaterialshallnotbeemployedforanenclosureofalineisolationmonitorintendedtobeconnecteddirectlytorigidconduitormetal-cladcable.Itisnotprohibitedfrombeingusedasanenclosureofaunitintendedtobeinstalledinanoverallmetalenclosurewithotherequipment,suchasinanisolatingpowerpanelassembly.

Whenanonmetallicenclosureisemployed,thecontinuityofthegroundingsystemshallnotrelyonthedimensionalintegrityofthenonmetallicmaterial.

Amongthefactorstakenintoconsiderationwhendeterminingtheacceptabilityofanonmetallicenclosureare:

Themechanicalstrength;

Resistancetoimpact;

Moisture-absorptiveproperties;

Combustibilityandresistancetoignitionfromelectricalsources;

Dielectricstrength,insulationresistance,andresistancetoarctracking;and

Resistancetodistortionandcreepingattemperaturestowhichthematerialissubjectedunderconditionsofnormalorabnormalusage.

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Allthesefactorsaretobeconsideredwithregardtoaging.

Ventilatingopenings

Ventilatingopeningsinanenclosure,includingperforatedholes,louvers,andopeningsprotectedbymeansofwirescreening,expandedmetal,orperforatedcovers,shallbeofsuchsizeorshapethatnoopeningpermitspassageofarodhavingadiameterof9/64inch(3.6mm).

Anenclosurehousingfusesoranyotheroverload-protectivedevice,andprovidedwithventilatingopenings,shallaffordadequateprotectionagainsttheemissionofflameormoltenmetal.

Theaveragethicknessofperforatedsheetmetalandsheetmetalemployedforexpanded-metalmeshshallnotbelessthan:

0.042inch(1.07mm),0.046inch(1.14mm)ifzinccoated,whenthemeshopeningsorperforationsare1/2in2(323mm2)orlessinareaand

0.080inch(2.04mm),0.084inch(2.14mm)ifzinccoated,forlargeropenings.

Exception:WhentheindentationofaguardorenclosurewalldoesnotaltertheclearancebetweenuninsulatedlivepartsandgroundedmetalandaffectperformanceadverselyorreducespacingsbelowtheminimumvaluegivenunderSpacings,Section

14

,0.021inch(0.53mm)expandedmetalmesh[0.024inch(0.59mm)ifzinccoated]isnotprohibitedfrombeingused,whentheexposedmeshonanyonesideorsurfaceofthedevicesoprotectedhasanareaofnotmorethan72in2(464mm2)andnodimensiongreaterthan12inches(305mm),orwhenthewidthofanopeningsoprotectedisnotgreaterthan3-1/2inches(90mm).

Thewiresofascreenshallnotbesmallerthan16AWG(1.3mmdiameter)andthescreenopeningsshallnotbegreaterthan1/8inch(3.2mm)squareinarea.

Covers

Anenclosurecovershallbehinged,sliding,pivotedorsimilarlyattachedwhenitprovidesreadyaccesstofusesoranyotherovercurrentprotectivedevice,theintendedprotectivefunctioningofwhichrequirerenewal,orwhenitisrequiredtoopenthecoverinconnectionwiththenormaloperationoftheunit.

Withreferenceto

7.6.1

,normaloperationisconsideredtobeoperationofaswitchfortestingorforsilencinganaudiblesignalapplianceoroperationofanyothercomponentofaunitwhichrequiressuchactioninconnectionwithitsintendedperformance.

Ahingedcoverisnotrequiredwhenitisnotnecessarytoopenthecoverinconnectionwithnormaloperationoftheunit,andtheonlyfuse(s)enclosedisforprotectionofportionsofinternalcircuitsagainstdamageresultingfromafault.Thefollowingorequivalentmarkingshallbeindicatedontheoutersurfaceofthecoverprovided:"CAUTION–CIRCUITFUSE(S)INSIDE–DISCONNECTPOWER-SUPPLYPRIORTOSERVICING."

Whenahingedcoverisrequired,itshallbeprovidedwithalatch,screw,orcatchtoholditclosed.Thehingedcoverofaunitintendedtobeinstalledwhereitisaccessibletootherthanauthorizedpersonnelshallbeprovidedwithakeylockorwithascrewrequiringatoolforremoval.

Anunhingedcovershallbesecurelyheldinplacebyscrewsortheequivalent.

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Glasspanels

Aglasspanelcoveringanobservationopening,otherthanametercover,shallbesecurelyheldinplacesothatitcannotbereadilydisplacedinserviceandshallprovideadequatemechanicalprotectionfortheenclosedparts.Thethicknessoftheglasspanelshallnotbelessthanthatindicatedin

Table7.3

.

Table7.3ThicknessofGlassCovers

Maximumsizeofopening

Minimumthicknessofglassinches (mm)

Lengthorwidth

inches (mm)

in2

Area

(cm2)

4

(102)

16

(103)

1/16

(1.6)

12

(305)

144

(927)

1/8

(3.2)

Over12

(305)

Over144

(927)

a

a1/8inch(3.2mm)ormore,dependinguponthesize,shape,andmountingoftheglasspanel.

Aglasspanelforanopeninghavinganareaofmorethan144squareinches(927cm2),orhavinganydimensiongreaterthan12inches(305mm),shallbesupportedbyacontinuousflangenotlessthan3/16inch(4.8mm)deepalongallfouredgesofthepanel.

Atransparentmaterialotherthanglass,employedasacoveroveranopeninginanenclosure,shallhavemechanicalstrengthequivalenttothatofglass,notintroduceariskoffire,distort,norbecomelesstransparentatthetemperaturetowhichitissubjectedunderallconditionsofintendeduse.

ElectricShock

Anypartthatisexposedonlyduringoperatorservicingshallnotpresenttheriskofelectricshock.SeeElectricShockCurrentTest,Section

28

.

Eachterminalprovidedfortheconnectionofanexternalantennashallbeconductivelyconnectedtothesupplycircuitgroundedconductor.Theresistanceoftheconductiveconnectionshallnotexceed5.2megohms.Thewattageratingshallbeatleast1/2watts,andtheconductiveconnectionshallbeeffectivewiththepowerswitchineithertheonoroffposition.

Exception:Theconductiveconnectionisnotrequiredtobeprovidedwhen:

Suchaconnectionisestablishedintheeventofelectricalbreakdownoftheantennaisolatingmeans;

Thebreakdowndoesnotresultinariskofelectricshock;and

Inaconstructionemployinganisolatingpowertransformer,theresistanceoftheconductiveconnectionbetweenthesupplycircuitandchassisdoesnotexceed5.2megohms.

Themaximumvalueof5.2megohmsspecifiedin

8.2

istoincludethemaximumtoleranceoftheresistorvalueused;thatis,aresistorrated4.2megohmswith20%toleranceoraresistorrated4.7megohmswitha10%toleranceisacceptable.Acomponentcomprisedofacapacitorwithabuilt-inshuntresistorthatcomplieswiththerequirementsforantennaisolatingcapacitorsisnotprohibitedfrombeingratedaminimumof1/4watt.

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Theinsertioninanysocketofanyvacuumtubeoritsglassormetalequivalentoflikedesignationusedintheproductshallnotresultinariskofelectricshock.

CorrosionProtection

Exceptasindicatedin

9.2

,ironandsteelparts,shallbeprotectedagainstcorrosionbyenameling,galvanizing,sherardizing,plating,orotherequivalentmeans.

Exception:Therequirementdoesnotapplyto:

Bearings,andthelike,wheresuchprotectionisimpracticableor

Minorparts,suchaswashers,screws,bolts,andthelike,whencorrosionofsuchunprotectedpartsdoesnotresultinariskoffire,electricshock,orinjurytopersons,orimpairtheoperationoftheunit.

Therequirementof

9.1

appliestoallenclosingcasesofsheetsteelorcastiron,andtoallspringsandotherpartsuponwhichintendedmechanicaloperationdepends.Partsmadeofstainlesssteel,properlypolishedortreated,whenrequired,donotrequireadditionalprotectionagainstcorrosion.Bearingsurfacesshallbeofsuchmaterialandconstructionastoresistbindingduetocorrosion.

Field-WiringSystemConnections

General

AlineisolationmonitorshallbeprovidedwithwiringterminalsorleadsfortheconnectionofconductorsofatleastthesizerequiredbyNFPA70,correspondingtotheratingoftheunit.

Thereshallbesufficientspacewithinaterminalorwiringcompartmenttopermitcompletionofallwireconnectionsspecifiedbytheinstallationwiringdiagram.

Theterminalpartstowhichwiringconnectionsaremadeshallconsistofbindingscrewswithterminalplateshavingupturnedlugsortheequivalenttoholdthewiresinposition.Otherterminalconnectionsarenotprohibitedfrombeingprovidedwhendeterminedtobeequivalent.

AwirebindingscrewemployedatawiringterminalshallnotbesmallerthanNo.6(3.5mmdiameter).Thescrewshallthreadintometal.

Exceptasnotedin

10.1.6

,aterminalplatetappedforaNo.6(3.5mmdiameter)wir