UL1047

STANDARDFORSAFETY

IsolatedPowerSystemsEquipment

MARCH26,2025-UL1047

tr1

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

ULStandardforSafetyforIsolatedPowerSystemsEquipment,UL1047SeventhEdition,DatedMarch26,2025

SUMMARYOFTOPICS

ThisnewSeventhEditionofANSI/UL1047datedMarch26,2025incorporateseditorialupdatesfromtheFebruary21,2025proposal(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.

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

MARCH26,2025

ANSI/UL1047-2025

1

UL1047

StandardforIsolatedPowerSystemsEquipment

FirstEdition–August,1976SecondEdition–December,1990ThirdEdition–March,1995FourthEdition–September,2003FifthEdition–October,2010

SixthEdition–October,2015SeventhEditionMarch26,2025

ThisANSI/ULStandardforSafetyconsistsoftheSeventhEdition.

ThemostrecentdesignationofANSI/UL1047asanAmericanNationalStandard(ANSI)occurredonMarch26,2025.ANSIapprovalforastandarddoesnotincludetheCoverPage,TransmittalPages,andTitlePage.

CommentsorproposalsforrevisionsonanypartoftheStandardmaybesubmittedtoULSEatanytime.ProposalsshouldbesubmittedviaaProposalRequestintheCollaborativeStandardsDevelopmentSystem(CSDS)at

.

OurStandardsforSafetyarecopyrightedbyULSEInc.NeitheraprintednorelectroniccopyofaStandardshouldbealteredinanyway.AllofourStandardsandallcopyrights,ownerships,andrightsregardingthoseStandardsshallremainthesoleandexclusivepropertyofULSEInc.

?2025ULSEInc.Allrightsreserved.

MARCH26,2025

UL1047

3

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

CONTENTS

INTRODUCTION

Scope 5

Glossary 5

Components 6

UnitsofMeasurement 6

ReferencedPublications 7

CONSTRUCTION

General 7

Enclosure 8

Ventilation 8

ConnectionsforWiringSystems 9

CorrosionProtection 9

Bases–InsulatingMaterial. 10

MountingofParts 10

Current-CarryingParts 12

PermanentlyConnectedEquipment 13

Field-WiringTerminalsandLeads 13

Cord-ConnectedEquipment 15

General 15

Strainrelief 15

Bushings 16

X-RayEquipment 16

WallModularUnits 16

InternalWiring 17

SeparationofCircuits 18

Factoryinstalled 18

Field-installedClass2 18

Field-WiringSpace 19

General 19

Wirebendingspace 19

Spacings 22

IsolationTransformers 25

LineIsolationMonitor 26

OvercurrentProtection 27

Switches 27

Receptacles 27

GroundingJacksandCordAssemblies 28

ReferenceGroundingBus 28

PERFORMANCE

Regulation 31

Temperature 31

LeakageCurrent 34

DielectricVoltage-Withstand 41

Stability 41

StrengthofInsulatingBaseandSupports 42

AbnormalOperation 42

Push-BackRelief 42

MANUFACTURINGANDPRODUCTIONTESTS

Production-LineDielectricVoltage-Withstand 42

Production-LineGroundingContinuity 44

RATING

Details 44

MARKING

Details 44

MARCH26,2025

UL1047

5

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

INTRODUCTION

Scope

Theserequirementscoverisolatedpowersystemsequipmentrated600Vacorless,intendedforinstallationanduseinnonhazardousareasinhealthcarefacilitiesinaccordancewiththerequirementsinArticle517oftheNationalElectricalCode,NFPA70,andintheStandardforHealthCareFacilities,NFPA99.

Theserequirementscoverisolatedpowercenters,eithercord-connectedorpermanentlywired,consistingofadistributionpanelthatincorporatesanisolationtransformer,oneormoreisolatedungroundedsecondarycircuitsterminatinginintegrallymountedgrounding-typereceptacles,areferencegroundingbusbar,andlineisolationmonitor.Isolatedpowercentersmayhaveprovisionforconnectionofgroundingconductorstoremotegroundingjacks,theroombondingpoints,andpatientequipmentgroundingpoints.Apermanentlywiredisolatedpowercentermayalsohaveprovisionforconnectiontoremotereceptaclesorindicators.

Theserequirementscoverconvertiblesystemunitsthatfacilitateatemporaryconversionofthepowersupplyforapowercenterfromagroundedsupplytoanisolatedsupply.

Theserequirementscoverisolatedpowerpanelboardsthatincorporatethesamefeaturesaspermanentlywiredisolatedpowercentersexceptthat:

Theymaybesuppliedfromremoteisolationtransformers;and

Thesecondaryisolatedcircuitsareintendedtobeconnectedbyconduittoremotelylocatedreceptacles.

Theserequirementscoverwallmodularunitscontainingisolatedpowersystems.

Theserequirementscovercord-connectedisolatedpowercenters,andpanelsintendedtosupplyx-rayequipmentonly.

Glossary

ForthepurposeofthisStandardthefollowingdefinitionsapply.

CONVERTIBLE-SYSTEMUNIT–Anenclosedassemblyincorporatinganisolationtransformerandlineisolationmonitorwithinterconnectingcordassembliesthatfacilitatetemporaryconversionofthepowersupplyforapowercenterfromagroundedsupplytoanisolatedsupply.Theunitisintendedforuseonlywiththespecificpowercentersforwhichithasbeendesigned.

FIELD-WIRINGTERMINAL–Aterminaltowhichasupplyorotherwirecanbeconnectedbyaninstallerinthefieldisafield-wiringterminalunlessaleadisprovidedaspartofapressureterminalconnector,orothermeansformakingtheconnectionisfactory-assembledtothewire.

LINEISOLATIONMONITOR–Atestinstrumentdesignedtocontinuallycheckthebalancedandunbalancedimpedancefromeachlineofanisolatedcircuittogroundandequippedwithabuilt-intestcircuittoactuateanalarmwithoutaddingtotheleakagecurrent.

MOMENTARYRATING–Aratingbasedonanoperatingintervalthatdoesnotexceed5seconds.

6

UL1047

MARCH26,2025

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

PATIENTEQUIPMENTGROUNDINGPOINT–Ajackorterminalbusthatservesasthecollectionpointforredundantgroundingofelectricappliancesservingapatientvicinityorforgroundingotheritemsinordertoeliminateelectromagneticinterferenceproblems.

REFERENCEGROUNDINGPOINT–Aterminalbusthatisanextensionoftheequipmentgroundingbusandisaconvenientcollectionpointforgroundingallelectricappliances,equipment,andexposedconductivesurfacesinapatientvicinity.

ROOMBONDINGPOINT–Agroundingterminalbusthatservesasthecollectionpointforgroundingexposedmetalorconductivebuildingsurfacesinaroom.

WALLMODULARUNIT–Afactory-builtwallsectionorsectionstypicallycontainingvariouscombinationsofgasoutlets,lightingfixtures,clocks,intercommunicationunits,andthelikeforusein,within,oraspartofhealth-carefacilities.OnlyunitscontainingisolatedpowersystemsequipmentarecoveredbythisStandard.Groundedpowercircuitsthatarephysicallysegregatedandseparatedmayalsobeincluded.

Components

AcomponentofaproductcoveredbythisStandardshall:

ComplywiththerequirementsforthatcomponentasspecifiedinthisStandard;

Beusedinaccordancewithitsrating(s)establishedfortheintendedconditionsofuse;and

Beusedwithinitsestablisheduselimitationsorconditionsforacceptability.

AcomponentofaproductcoveredbythisStandardisnotrequiredtocomplywithaspecificcomponentrequirementthat:

InvolvesafeatureorcharacteristicnotrequiredintheapplicationofthecomponentintheproductcoveredbythisStandard;or

IssupersededbyarequirementinthisStandard;or

Isseparatelyevaluatedwhenformingpartofanothercomponent,providedthecomponentisusedinaccordancewithitsestablishedratingsandlimitations.

Specificcomponentsareincompleteinconstructionfeaturesorrestrictedinperformancecapabilities.Suchcomponentsareintendedforuseonlyunderlimitedconditions,suchascertaintemperaturesnotexceedingspecifiedlimits,andshallbeusedonlyunderthosespecificconditions.

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

UnitsofMeasurement

Valuesstatedwithoutparenthesesaretherequirement.Valuesinparenthesesareexplanatoryorapproximateinformation.

MARCH26,2025

UL1047

7

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

ReferencedPublications

AnyundatedreferencetoacodeorstandardappearingintherequirementsofthisStandardshallbeinterpretedasreferringtothelatesteditionofthatcodeorstandard.

ThefollowingpublicationsarereferencedinthisStandard:

ASTME28,StandardTestMethodsforSofteningPointofResinsDerivedfromPineChemicalsandHydrocarbons,byRing-and-BallApparatus

ASTME230/E230M,StandardSpecificationforTemperature-ElectromotiveForce(emf)TablesforStandardizedThermocouples

NFPA99,HealthCareFacilitiesCode

UL5,SurfaceMetalRacewaysandFittings

UL50,EnclosuresforElectricalEquipment,Non-EnvironmentalConsiderations

UL94,TestsforFlammabilityofPlasticMaterialsforPartsinDevicesandAppliances

UL224,ExtrudedInsulatingTubing

UL486A-486B,WireConnectors

UL510,PolyvinylChloride,PolyethyleneandRubberInsulatingTapeUL723,TestforSurfaceBurningCharacteristicsofBuildingMaterialsUL1022,LineIsolationMonitors

UL5085-1,Low-VoltageTransformers–Part1:GeneralRequirements

UL5085-2,Low-VoltageTransformers–Part2:GeneralPurposeTransformersUL5085-3,Low-VoltageTransformers–Part3:Class2and3TransformersCONSTRUCTION

General

Isolatedpowersystemsequipmentshallemploymaterialsthroughoutthatareacceptablefortheapplication,andshallbemadeandfinishedwiththedegreeofuniformityandgradeofworkmanshippracticableinawell-equippedfactory.

Aconvertiblesystemunitshallbedesignedtoconvertaspecificpowercenterfromagroundedsupplytoanisolatedsupply.Thespecificpowercentershallconsistofovercurrentprotectiondevices,receptacles,groundingjacksandcomponentsotherthanthetransformerandlineisolationmonitorthathavebeenpreviouslypermanentlyinstalled.Alsothegroundingconductorfromthegroundedsupplytothedistributionpanelormodularwallsectionshallremaincontinuousandsoarrangedthatitisnotinterruptedbytheconvertingprocedure.

8

UL1047

MARCH26,2025

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

Anenclosure,anopening,aframe,aguard,aknob,ahandle,orthelikeshallnotbesufficientlysharptocauseariskofinjuryinnormalmaintenanceoruse.

Equipmentshallbeformedsothatitwillhavethestrengthandrigiditynecessarytoresisttheabusestowhichitmaybesubjected,withoutincreasingtheriskoffire,electricshock,orinjurytopersonsduetototalorpartialcollapsewithresultingreductionofspacings,looseningordisplacementofpartsorotherseriousdefects.

Enclosure

TheenclosureofisolatedpowersystemsequipmentshallcomplywithUL50.

Exception:AnenclosuremaybeventilatedinaccordancewithVentilation,Section

8

.

Anenclosurecoverordoorshallbehinged,sliding,orsimilarlyattachedsothatitcannotbewhollydetachedwithouttheuseofatool,ifitgivesaccesstoafuseoranyotheroverload-protectivedevicethenormalfunctioningofwhichrequiresrenewal,orifitisnecessarytoopenthecoverduringnormaloperationofthedevice.

Ventilation

Aventilatingopeninginanenclosureshallbeconstructedandlocatedsothatnoflameormoltenmetalwillbeemittedduringthearcingencounteredduringtheoperationoffuses,switches,orcircuitbreakers.

Unlesstheopeningisremotefromthearcingpart,therequirementin

8.1

necessitatestheinterposingofanoncombustiblebarrierbetweenaventilatingopeningandapossiblesourceofarcingsuchasaswitch,fuse,andthelike.

Thebarriershallbeofsuchdimensionsandlocatedsothatstraightlinesdrawnfromanyarcingpartpasttheedgeofthebarrierwilldefineanareaattheplaneoftheopening1/4inch(6.4mm)beyondtheedgesoftheopening.

Asheet-steelbarriershallnotbelessthan0.053inch(1.35mm)thickifuncoatedandnotlessthan

0.056inch(1.42mm)thickifgalvanized.

Exception:Asteelbarriermaybeoflesserthicknessprovideditsstrengthandrigidityisnotlessthanthatofaflatsheetofsteelofthespecifiedthicknesshavingthesamedimensionsasthebarrier.

Thethicknessofanonmetallicbarriermaybelessthan1/4inch(6.4mm)ifthebarrierislocatedsothatitwillnotbesubjecttomechanicalabuseduringinstallationandislocatedandsupportedsothatitwillhavethenecessarymechanicalstrengthandrigidity.

Aventilatingopeninginanenclosureshallhavesuchsizeorshape,orshallbecoveredbyscreeningorbyanexpanded,perforated,orlouveredmetalpanelsothatatestrodofthediameterspecifiedin

8.7

willnotentertheopening.

Thetestrodmentionedin

8.6

shallbe33/64inch(13.2mm)indiameteriftheplaneoftheopeningislessthan4inches(102mm)fromanuninsulatedlivepart,or49/64inch(19.4mm)indiameteriftheplaneoftheopeningis4inchesormorefromsuchpart.

Thesize,shape,andlocationofascreenedopeningshallbesuchasnottoundulyweakentheoverallenclosure.

MARCH26,2025

UL1047

9

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

Theareaofaventilatingopeninginanenclosureshallnotexceed80in2.

Thewiresofascreenrequiredtoprotectaventilatingopeningshallnotbesmallerthan16AWG(1.3mm2)ifthescreenopeningsare1/2in2orlessinarea,andnotsmallerthan12AWG(3.3mm2)forlargerscreenopenings.Asupplementaryscreenofsmalleropeningsmaybeadditionallyprovided.Thesupplementaryscreenisnottobeconsideredintheevaluationoftheventilatingopeningscreen.

Perforatedsheetsteelandsheetsteelemployedforexpanded-metalmeshshallnotbelessthan

0.042inch(1.07mm)thickifuncoated,or0.045inch(1.14mm)ifgalvanizedifthemeshopeningsorperforationsare1/2in2orlessinarea,andshallnotbelessthan0.080inch(2.03mm)thickifuncoated,or

0.084inch(2.13mm)thickifgalvanizedforlargeropenings.

Exception:Wheretheindentationofaguardorenclosurecannotaltertheclearancebetweenuninsulatedlivepartsandgroundedmetalsoastoaffectperformanceadverselyorreducespacingsbelowtheminimumvaluesgivenin

Table22.1

,perforatedsheetsteelandsheetsteelemployedasexpandedmetal-meshnotlessthan0.020inch(0.51mm)thickifuncoated,orifgalvanized0.023inch(0.58mm)thickmaybeused.

Agrillconstructioncomplyingwiththeintentoftherequirementsin

8.11

maybeacceptedifithasbeenfoundtobesuitablefortheparticularapplication.

Thelengthofventilatinglouversinanenclosureshallnotexceed12inches(305mm).

Aseparatelouveredpanelthatisrivetedorweldedinplaceoveraventilatingopeningintheenclosuremaybeofnotlessthan0.032inch(0.81mm)thickifuncoatedandnotlessthan0.034inch(0.86mm)thickifgalvanizedsheetsteel.

Aventilatingopeninginthetopoftheenclosureshallbecoveredbyahoodorprotectiveshieldspacedabovetheopeningtopreventtheentryofforeignmaterial.

ConnectionsforWiringSystems

Knockoutsprovidedintheenclosureshallbeofthepropersize;andshallbesolocatedthattheinstallationofbushingswillnotresultinspacingsbetweenlivepartsandbushingsoflessthantheminimumrequirementsspecifiedin

Table22.1

.Atleasttwooftheknockoutsshallbesizedtoaccommodatethelargestsizewiringwhichcouldbeusedintheinstallationofthepanel.

CorrosionProtection

Ironandsteelpartsshallbesuitablyprotectedagainstcorrosionbyenameling,galvanizing,sherardizing,platingorotherequivalentmeans.

Therequirementof

10.1

appliestoallenclosingcaseswhetherofsheetsteelorcastiron,andtoallspringsandotherpartsuponwhichpropermechanicaloperationmaydepend.Itdoesnotapplytobearings,laminations,andthelike,ifthefailureofsuchunprotectedpartswouldnotbelikelytoresultinahazardousconditionorintheequipment'soperationbeingaffectedadversely.Partsmadeofstainlesssteelofthetypehavinginherentresistancetocorrosion(properlypolishedortreated,ifnecessary)donotrequireadditionalprotectionagainstcorrosion.Bearingsurfacesshouldbeofsuchmaterialsanddesigntoensureagainstbindingduetocorrosion.

10

UL1047

MARCH26,2025

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

Bases–InsulatingMaterial

Abaseformountinguninsulatedlivepartsshallbestrong,noteasilyignited,moisture-resistantandinsulating.Thebaseshallbeofsuchmaterialthatitwillwithstandthemostsevereconditionslikelytobemetinservice.

Ordinaryfiber,rubber,andso-calledhot-moldedshellacandtarcompositionsarenotacceptableforthemountingofuninsulatedlivemetal.

Insulatingmaterialincludingbarriersbetweenpartsofoppositepolarityandmaterialthatmaybesubjecttotheinfluenceofthearcformedbytheopeningofcontactsshallbesuitablefortheparticularapplication.

Alivescrewheadornutontheundersideofaninsulatingbaseshallbereliablypreventedfromlooseningandshallbeadequatelyinsulatedorspacedfromthemountingsurface.Thismaybeaccomplishedby:

Countersinkingsuchpartsnotlessthan1/8inch(3.2mm)intheclearandthencoveringthemwithawaterproof,insulatingsealingcompoundthatdoesnotsoftenatatemperature15°C(27°F)higherthanitsnormaloperatingtemperatureinthedevice,andnotlessthan90°C(194°F)inanycase;or

Reliablysecuringsuchpartsandinsulatingthemfromthemountingsurfacebymeansofabarrier,ortheequivalent,orbymeansofthrough-airorover-surfacespacingsnotlessthantheminimumvaluesspecifiedin

Table22.1

.

Withreferenceto

11.4

,alockwasher,properlyapplied,isacceptableasameansofpreventingthelooseningofascrewornut.

Withreferenceto

11.4

(a),determinationofthesofteningpointofasealingcompoundistobemadeinaccordancewithASTME28.

MountingofParts

Allpartsshallbesecurelymountedinpositionandpreventedfromlooseningorturningifsuchmotionmayaffectadverselythenormalperformanceoftheequipment,ormayincreasetheriskoffire,shock,andinjurytopersonsincidenttotheoperationoftheequipment.

Uninsulatedlivemetalpartsshallbesecuredtotheirsupportingsurfacessothattheywillbepreventedfromturningorshiftinginpositionifsuchmotionmayresultinareductionofspacingstolessthanthoseindicatedin

Table22.1

.Thesecurityofcontactassembliesshallbesuchastoensurethecontinuedalignmentofcontacts.Seealso

15.9

.

Withreferenceto

12.1

and

12.2

,frictionbetweensurfacesisnotacceptableasameanstopreventturning,loosening,orshiftingofapart;butasuitablelockwasher,properlyapplied,maybeaccepted.

Thewiringofanelectricalcomponentmountedonadoororhingedcovershallbefactoryinstalledusingsuitablepressurewireconnectors,ateachend,thatcomplywithUL486A-486B.Thereshallbenoprovisionforconnectionoffieldwiring.

ExceptionNo.1:Quick-connectterminalsmaybeusedforsignallights,buzzersorswitches,ifclampsortheequivalentareprovidedwherenecessarytopreventstressontheterminations.

MARCH26,2025

UL1047

11

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

ExceptionNo.2:Provisionmaybemadeforfield-installationofclocks,timers,orlightingfixturesbymeansofplugsandreceptacles.

Wiresconnectedtoacomponentmountedonadoororhingedcovershall:

Notbelargerthan12AWG(3.3mm2);

Bestranded;

Haveatleast1/32inch(0.79mm)thickinsulation;and

Becabledorroutedsoastoavoidbeingdamagedduringopeningandclosingofthedoororhingedcover.

ExceptionNo.1:Abundleorcableofnotmorethan12wires,inadditiontothebondingwirementionedin

12.6

,maycontain10AWG(5.3mm2)wires.

ExceptionNo.2:Abundleorcableofnotmorethan4wires,inadditiontothebondingwirementionedin

12.6

,maycontain10AWGwires.

Adoororhingedcoveronwhichelectricalcomponentsaremountedshallbebondedtotheboxwithawirenotsmallerthan10AWG(5.3mm2).

Electricalpartsofacomponentmountedonacovershallbelocatedorenclosedsothatwiththecoveropen,personsareprotectedagainstunintentionalcontactwithuninsulatedliveparts.

Exception:Livepartsmaybeaccessibleifthevoltageinvolvedis42.4Vpeakorlessoriftheavailablecurrentmeasuredthrougha1500?noninductiveresistoris0.5mAorless.

Notmorethansixreceptaclesandsixgroundingjacksshallbemountedonasinglecoverofaremoteassembly.

Receptaclesandgroundingjacksmountedonacoverofaremoteassemblyshallbefactorywiredtopressurewireterminalsintheremoteassemblybox.

ExceptionNo.1:Factorywiringisnotrequiredif:

Notmorethansixdevices(receptacles,groundingjacksandsignallights)areprovided;

Thefieldinstalledwiresdonotexceedsix12AWG(3.3mm2)plusonegroundingconductor;

Itisnotnecessarytoremovethedevicesfromthecoverinordertodothewiring;and

Theassemblyisnotintendedforwiringotherthanthatassociatedwiththereceptaclesandjacks.

ExceptionNo.2:Asinglegroundingwiremaybefieldwiredifnoreferencegroundingbusisprovidedintheremoteassemblybox.

Factorywiringofreceptaclesandgroundingjacksmountedonacoverofaremoteassemblyshallbestrandedandshallhaveatleast1/32-inch(0.79-mm)thickinsulation.

Theenclosureofaremoteassemblyshallhaveadepththataccommodatesthereinstallationofthecoverafterwiringiscompletedwithoutforcingconductorsagainstpartsmountedonthecover.Parts

12

UL1047

MARCH26,2025

ULSEINC.COPYRIGHTEDMATERIAL–NOTAUTHORIZEDFORFURTHERREPRODUCTIONORDISTRIBUTIONWITHOUTPERMISSIONFROMULSEINC.

mountedintheboxsuchaswireterminatingmeansshallbelocatedsothatwiresconnectedtopartsonthecoverarenotforcedagainstsuchpartsafterthecoverisreinstalled.

Thecoverofaremoteassemblythatisintendedtobefieldwiredshallhavesuitablemeansforitssupportduringfieldwiringsothatthecoverassemblydoesnothangcompletelyontheconnectedwires.Thismaybeaccomplishedbytheuseofhinges,byinstructionsanddesigntopermithangingthecoverfromthelowerboxcoverscrews,ortheequivalent.

Ifpartsareheldtogetherbyscrews,ametalthreadedpartshallhavenofewerthantwofull,clean-cutthreadsengaged.Ifthescrewdoesnotextendallthewaythroughathreadedpart,thetaperorleadandthefirstfullthreadaretobedisregardedinadeterminationofthenumberofthreadsengaged.

Thetransformermaybeshippedseparatelyfromtheequipmentproviding:

Theequipmentismarkedtoidentifythetransformerandthelocationwhereitistobemounted;

Allwiringintheequipmentisprovidednecessitatingonlytheline,loadandgroundingconnectionsasrequired,tothetransformertobemade;and

Allnecessarymountinghardwareisprovidedontheequipment.

Apowercenterinteriororapanelboardinteriormaybeshippedseparatelyfromitsenclosureproviding:

Theenclosure,interior,andtransformerwhenrequired,aremarkedtoindicateunitsthataretobeusedtogether;

Theequipmentismarkedwithinstructionsforproperfield-installationandwiring;

Theinterioriscapableofbeinginstalledwithoutremovingordisplacingenclosurepartsotherthanacover;

Allwiringisprovidednecessitatingfieldconnectionsonly:

Toline,load,andground;

Betweentransformerprimaryandthemainswitchorcircuitbreaker,whenprovided;

Betweentransformersecondaryandinterior;

Betweenthereferencegroundbusandtheenclosure;and

Betweenthetransformercoreandthereferencegroundbusoftheenclosure;

Allnecessarymountinghardwareisprovidedontheequipment;

ThenecessarywiringconnectionsandroutingofwiringcomplieswiththerequirementsinSeparationofCircuits,Section

20

;and

Allwiringhasbeenpreca