GB 50257-2014 GB50257-2014电气装置安装工程．爆炸和火灾危险环境电气装置施工及验收规范:英文

GB50257-2014

CODEFORCONSTRUCTIONANDACCEPTANCE

OFELECTRICEQUIPMENTONFIRE

ANDEXPLOSIONHAZARD

ELECTRICALEQUIPMENTINSTALLATIONENGINEERING专用

电气装置安装工程

爆炸和火灾危险环境电气装置施工及验收规范

人人文库

IssuedonDecember2，2014ImplementedonAugust1，2015

itheMinistryofHousingandUrban-RuralDevelopment（MOHURD）

andtheGeneralAdministrationofQualitySupervision，Inspection

350.00andQuarantineof（AQSIQ）thePeople'sRepublicofChina

NATIONALSTANDARD

OFTHEPEOPLE'SREPUBLICOFCHINA

CODEFORCONSTRUCTIONANDACCEPTANCE

OFELECTRICEQUIPMENTONFIRE

ANDEXPLOSIONHAZARD

ELECTRICALEQUIPMENTINSTALLATIONENGINEERING

GB50257-2014

DevelopedbyChinaElectricityCouncil

ApprovedbyTheMinistryofHousingandUrbanRuralDevelopmentofthe

-

People'sRepublicofChina专用

ImplementationDateAugust1，2015

人人文库

ChinaPlanningPress

Beijing2021

ChineseeditionfirstpublishedinthePeoplesRepublicofChinain2014

EnglisheditionfirstpublishedinthePeoplesRepublicofChinain2021

byChinaPlanningPress

rd专用

3Floor，CTower，GuohongBuilding

No.A11，Muxidi-Beili，XichengDistrict

Beijing，100038

PrintedinChinabyBeijingJingyintangGraphicPrintingCenter

©2014bytheMinistryofHousingandUrban-RuralDevelopmentof

thePeoplesRepublicofChina

Allrightsreserved.Nopartofthispublicationmaybereproducedortransmittedinanyformor

byanymeans，graphic，electronic，ormechanical，includingphotocopying，recording，

oranyinformationstora人人文库geandretrievalsystems，withoutwrittenpermissionofthepublisher.

Thisbookissoldsubjecttotheconditionthatitshallnot，bywayoftradeorotherwise，belent，

resold，hiredoutorotherwisecirculatedwithoutthepublisherspriorconsentinanyformof

blindingorcoverotherthanthatinwhichthisispublishedandwithoutasimilarcondition

includingthisconditionbeingimposedonthesubsequentpurchaser.

ISBN978-7-5182-1368-9

中华人民共和国住房和城乡建设部公告

2020年第13号

住房和城乡建设部关于发布《建设工程施工现场供用

电安全规范》等10项工程建设标准英文版的公告

现批准《建设工程施工现场供用电安全规范》（GB50194-2014）、《电气装置安装工程起

重机电气装置施工及验收规范》（GB50256-2014）、《电气装置安装工程电力变流设备施

工及验收规范》（GB50255-2014）、《电气装置安装工程爆炸和火灾危险环境电气装置施

工及验收规范》（GB50257-2014）、《电气装置安装工程66kV及以下架空电力线路施工及专用

验收规范》（GB50173-2014）、《有色金属选矿厂工艺设计规范》（GB50782-2012）、《工业建

筑供暖通风与空气调节设计规范》（GB50019-2015）、《地下水封石洞油库施工及验收规

范》（GB50996-2014）、《炼油装置火焰加热炉工程技术规范》（GB/T51175-2016）、《石油

化工企业总图制图标准》（GB/T51027-2014）等10项工程建设标准英文版。工程建设标

准英文版与中文版出现异议时，以中文版为准。

工程建设标准英文版由住房和城乡建设部组织中国计划出版社出版发行。

中华人民共和国住房和城乡建设部

2020年1月14日

人人文库

AnnouncementoftheMinistryofHousingandUrban-Rural

DevelopmentofthePeople'sRepublicofChina

No.594

AnnouncementoftheMinistryofHousingandUrbanRuralDevelopmenton

-

PublishingNationalStandardofCodeforConstructionandAcceptanceof

ElectricEquipmentonFireandExplosionHazardElectrical

EquipmentInstallationEngineering

CodeforConstructionandAcceptanceofElectricEquipmentonFireandExplosionHazard

ElectricalEquipmentInstallationEngineeringhasbeenapprovedasanationalstandardwithaserial

numberofGB50257-2014，andwillbeimplementedonAugust1，2015.Inthiscode，Articles（Items）

5.1.3，5.1.7，5.2.1，5.4.2（1），7.1.1and7.2.2aremandatoryonesandmust专用beimplementedstrictly.The

formereditionofthestandardGB50257-96CodeforConstructionandAcceptanceofElectricDevice

forExplosionAtmospheresandFireHazardElectricalEquipmentInstallationEngineeringwillbe

cancelledandreplacedaccordingly.

AuthorizedbytheResearchInstituteofStandardsandNormsofMinistryofHousingandUrban

-

RuralDevelopmentofthePeople'sRepublicofChina，thiscodeispublishedanddistributedby

ChinaPlanningPress.

MinistryofHousingandUrbanRuralDevelopmentofthePeople'sRepublicofChina

-

December2，2014

人人文库

Foreword

ThiscodeisarevisionofGB50257-96CodeforConstructionandAcceptanceofElectricDevice

forExplosionAtmospheresandFireHazardElectricalEquipmentInstallationEngineeringmadeby

theChinaElectricityCouncilandStateNuclearPowerEngineeringCompany（SNPEC）incooperation

withtheorganizationsconcerned，accordingtotherequirementsofDocumentJIANBIAO〔2009〕No.88

issuedbytheMinistryofHousingandUrbanRuralDevelopmentofthePeople'sRepublicofChina

-

（MOHURD）—"NoticeonPrintingandDistributing'theDevelopmentandRevisionPlanofNational

EngineeringConstructionStandardsin2009'".

Intheprocessofrevision，therevisionpanelsummarizednewrequirementsforandrelevant

scientificresearchandfieldpracticeexperienceinconstructionandacceptanceofelectricequipmenton

fireandexplosionhazardsinceGB50257-96CodeforConstructionandAcceptanceofElectricDevice

forExplosionAtmospheresandFireHazardElectricalEquipmentInstallationEngineeringwas

implemented，andcollectedwidecommentsfrominterestsconcerned.

Thiscodeconsistsof8chaptersand1appendix，covering：generalprovisions，terms，basicrequire-

ments，installationofexplosionproofelectricalequipment，electricalcircuit专用forexplosiveatmosphere，

-

electricalequipmentinfirehazardousenvironment，grounding，andprojectacceptanceetc.

Ascomparedwiththeoriginalcode，thefollowingmainamendmentsaremadeinthisrevision：The

twochapters"Terms"and"BasicRequirements"areadded，provisionsinsomechaptersaremodified，

articlesthatdonotreflectthecurrenttechnicalprogressaredeleted.

Theprovisionsprintedinboldtypearemandatoryonesandmustbeimplementedstrictly.

Thiscodeisunderthejurisdictionof，anditsmandatoryprovisionsareinterpretedbytheMinistry

ofHousingandUrbanRuralDevelopmentofthePeople'sRepublicofChina，ChinaElectricityCouncil

-

isresponsibleforitsroutinemanagement，andSNPECisinchargeoftheexplanationoftechnical

specifications.Therlevantopinionsandadvicewhenevernecessarycanbepostedorpassedonto

e，，

SNPEC（Address：BuildingNo.2，No.888TianlinRoad，MinxingDistrict，Shanghai，Postcode：200233）

forreferenceincaseofrevisioninthefuture.

ChiefDevelopmentOrganizations，CoDevelopmentOrganizations，ChiefDrafters，ChiefReviewers

-

andMainTranslatorsofthiscodeareasfollows：

ChiefDevelopmentOrganizations:

人人文库ChinaElectricityCouncil

StateNuclearPowerEngineeringCompany

Co-DevelopmentOrganizations:

ChinaGezhoubaGroupElectricPowerCo.，Ltd.

ShandongElectricPowerTransmission&SubstationEngineeringCo.，Ltd.

TianjinElectricPowerConstructionCompany

NanyangExplosionProtectedElectricalApparatusResearchInstitute

ChinaHelonExplosionproofElectricCo.，Ltd.

-

·1·

ChiefDrafters:

SUNKebinZOUYingnanTIANXiaoGEZhanyuGAOPengfeiLICong

JINGJinWANGGengZHANGGangXIEShaojian

ChiefReviewers:

XUJunZHOUYongliZHUZhiqiangWANGGuominWANGMin

LIUJunBAIYongLIUYujieZHOUJianWANGJian

LIDaolinHEZhijiangQINJianqing

MainTranslators:

LIQishengZENGQingyuYOUXiangfeiXUJunPANGYouyiJINGJin

LIUJianxia

专用

人人文库

2··

Contents

1Generalprovisions……………………（1）

2Terms……………………（2）

3Basicrequirements……………………（4）

4Installationofexplosionproofelectricalequipment…………………（6）

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4.1Generalrequirements……………………（6）

4.2Installationofflameproofelectricalequipment……………（6）

4.3Installationofincreasedsafetyandtypeofprotection"n"……………………（7）

4.4Installationofpressurization"p"…………（8）

4.5Installationofoilimmersion"o"…………（8）

4.6Installationofintrinsicsafety"i"…………（9）

4.7Installationoftypeofdustex……………（9）

-

5Electricalcircuitforexplosiveatmosphere…………（11）

5.1Generalrequirements……………………（11）

5.2Cablingroutingforexplosiveatmosphere…………………（12）

5.3Cableandwiringinconduitforexplosiveatmosphere专用………（13）

5.4Circuitofintrinsicsafety"i"equipmentandassociatedequipment……………（15）

6Electricalequipmentinfirehazardousenvironment…………………（16）

6.1Generalrequirements……………………（16）

6.2Installationofelectricalequipment………………………（16）

6.3Electricalcircuit…………………………（16）

7Grounding………………（18）

7.1Protectivegrounding……………………（18）

7.2Electrostaticproofgrounding……………（18）

8Projectacceptance………………………（20）

AppendixAElectricalclearanceandcreepagedistancebetweenexposedliveparts，

aswellasbetweenexposedlivepartsandmetalenclosureofthe

explosionproofelectricalequipment……………………（21）

-

Explanationofwordinginthiscode………………………（24）

Listofquotedstandards……………………（25）

Addition：Explanation人人文库ofprovisions………………………（27）

1Generalprovisions

1.0.1Thiscodeisformulatedwithaviewtoensuringsatisfactoryinstallationandsafeoperationof

electricalequipmentinenvironmentsexposedtoexplosionandfirehazards，promotinginstallation

technologies，andensuringthesafetyofpeopleandproperty.

1.0.2Thiscodeappliestoconstructionandacceptanceofelectricalequipmentinareaswhere

explosivemixtureofgas，vapor，dustandfiberormaterialsthatmayleadtofireexistormayexistduring

production，processing，treatment，handlingorstorage.

1.0.3Thiscodedoesnotapplytoconstructionandacceptanceofelectricalequipmentinthefollowing

atmospheres：

1Undergroundmines.

2Placeswheregunpowder，explosives，primerandfusearemanufactured，usedorstoredor

whereinitiatingexplosivedevicesaremanufactured.

3Areasaccommodatingelectricalequipmentusedforelectrolysisandelectroplatingin

productionaswellasdirectlylinkedtotheproductionprocess.

4Atmosphereswherestrongoxidantisusedandmaterialscanfire专用withoutanexternaligniting

source.

5Land，waterandairtransportationvehiclesaswellasoffshoreandonshoreoilplatforms.

6Nuclearislandinanuclearpowerplant.

7Pipelinesusingodorizednaturalgasasthefuelforheating，airconditioning，cookingand

washingaswellassimilarpipelines.

8Medicaltreatmentrooms.

9Disastrousaccidents.

1.0.4Notonlytherequirementsstipulatedinthiscode，butalsothoseinthecurrentrelevantonesof

thenationshallbecompliedwith.

人人文库

·1·

2Terms

2.0.1Explosiveatmosphere

Mixturewithair，underatmosphericconditions，offlammablesubstancesintheformofgases，

vapors，dusts，hazes，fibersorflyingsinwhich，afterignitionhasoccurred，combustionspreadstothe

entireunburnedmixture.

2.0.2Explosivedustatmosphere

Mixturewithair，underatmosphericconditions，offlammablesubstancesintheformofdusts，fibers

orflyingsinwhich，afterignitionhasoccurred，combustionspreadstotheentireunburnedmixture.

2.0.3Explosivegasatmosphere

Mixturewithair，underatmosphericconditions，offlammablesubstancesintheformofgasesor

vaporsinwhich，afterignitionhasoccurred，combustionspreadstotheentireunburnedmixture.

2.0.4Hazardousarea

Anareainwhichtheexplosivemixtureexistingorexpectedtoexistisinsuchanamountthat

specialmeasuresneedtobetakenforthestructure，installationanduseofelectricalequipment.

2.0.5Zone0专用

Anareainwhichexplosivegasmixtureispresentcontinuouslyorforlongperiods.

2.0.6Zone1

Anareainwhichexplosivegasmixtureislikelytoappearinnormaloperation.

2.0.7Zone2

Anareainwhichexplosivegasmixtureisnotlikelytoappearinnormaloperation，orevenit

appears，itwillexistonlyforashorttime.

2.0.8Zone20

Anareainwhichdustcloudinairispresentinanexplosiveatmospherecontinuously，forlong

periodsorfrequently.

2.0.9Zone21

Anareainwhichdustcloudinairisverylikelytooccurinanexplosiveatmosphereinnormal

operationoccasionally.

2.0.10Zone22

Anareainwhichdustcloudinairisunlikelytooccurinanexplosivedustatmosphere，orevenifit

doesoccur，itwill人人文库onlyexistforashorttime.

2.0.11Typeofprotection

Specificmeasuresappliedtoelectricalequipmenttoavoidignitionofasurroundingexplosive

atmosphere.

2.0.12Intrinsicsafety"i"

Atypeofprotectionbasedupontherestrictionofelectricalenergywithinequipmentandof

interconnectingwiringexposedtoanexplosiveatmospheretoalevelbelowthatwhichcancause

ignitionbyeithersparkingorthermaleffect.

Intrinsicallysafecircuit

2.0.13-

·2·

Acircuitinwhichanysparkorthermaleffectproducedinnormaloperationandspecifiedfault

conditionsisnotcapableofignitingagivenexplosivegasatmosphere.

Intrinsicallysafeelectricalequipment

2.0.14-

Electricalequipmentinwhichallthecircuitsareintrinsicallysafe.

2.0.15Associatedelectricalequipment

Electricalequipmentwhichcontainsbothintrinsicallysafecircuitsandnonintrinsicallysafecircuits

-

andisconstructedsothatthenonintrinsicallysafecircuitscannotadverselyaffecttheintrinsicallysafe

-

circuit.

2.0.16Pressurization"p"

Atypeofprotectionagainsttheingressoftheexternalexplosivegasintoanenclosureoraroomby

maintainingprotectivegasthereinatapressureabovethatoftheexternalatmosphere.

2.0.17Oilimmersion"o"

Atypeofprotectionwhereelectricalequipmentorpartsofelectricalequipmentareimmersedin

protectivefluidinsuchawaythatanexplosivegasatmospherewhichmaybeabovetheliquidoroutside

theenclosurecannotbeignited.

2.0.18Typeofprotection"n"

Atypeofprotectionappliedtoelectricalequipmentsuchthat，innormaloperationandincertain

specifiedabnormalconditions，itisnotcapableofignitingasurroundingexplosivegasatmosphere.

2.0.19Flameproofenclosure"d"专用

Atypeofprotectioninwhichtheenclosureofelectricalequipmentcanbearanyexplosionof

explosivemixtureenteringtheelectricalequipmentthroughanyjointsurfaceoftheenclosureor

structuralgapwithoutdamageandwillnotigniteanexternalexplosivegasatmospherecontainingone

ormorekindsofgasorsteam.

2.0.20Increasedsafety"e"

Atypeofprotectioninwhichelectricalequipmentisprotectedwithsomeadditionalmeasuresto

improveitssafetyandtopreventtheoccurrenceofhazardoustemperature，arcandsparksinnormal

operationorincertainspecifiedabnormalconditions.

Notes：1Thistypeofprotectionisexpressedwith"e"，andtheadditionalmeasuresarethosecomplyingwithrequirementsforsuchtypeof

protection.

2Thedefinitionofincreasedsafety"e"doesnotcovertheequipmentproducingsparksorarcduringnormaloperation.

人人文库

·3·

3Basicrequirements

3.0.1Installationofelectricalequipmentinexplosionandfirehazardousenvironmentshallbecarried

outincompliancewithapproveddesigndocuments.

3.0.2Transportationandstorageofelectricalequipmentandcomponentsshallsatisfyrequirements

setforthinthemanufacturer'stechnicaldocuments.

3.0.3Equipmentandcomponentsusedshallbeaccompaniedwithcertificateofconformity.The

equipmentshallhaveanameplateandanexplosionprooflabelifitisapieceofexplosionproof

--

equipment.

3.0.4Theequipmentandcomponentsshallbeinspectedandaccepteduponarrivalatthesiteandshall

complywiththefollowingrequirements：

1Thepackageandsealingshallbeingoodcondition.

Unpacktocheckthespecificationsandexplosionproofmarkforcompliancewiththedesign

2-

requirements，andaccessoriesandsparepartsforcompleteness.

3Manufacturer'stechnicaldocumentsshallbecomplete.

4Thenameplateofexplosionproofelectricalequipmentshall专用havetheexplosionproof

--

certificatenumberissuedbyacompetentinspectionagency.

5Nodamage，corrosionormoistureshallbefoundduringvisualinspection.

3.0.5Worksafetymeasuresforconstructionshallcomplywithrequirementssetforthinthiscodeand

manufacturer'stechnicaldocuments.Inexpansionorrenovationprojects，thesite'ssafetyrulesrelated

toconstructionshallbefollowed.Forimportantprocesses，specialsafetymeasuresandwork

instructionsshallbeworkedoutbeforehand.

3.0.6Constructionofbuildingsassociatedwithinstallationofelectricalequipmentinexplosionandfire

environmentshallmeetthefollowingrequirements：

1Theconstructionqualityofbuildingsandstructuresshallmeettherelevantprovisionsinthe

currentnationalstandardGB50300UnifiedStandardforConstructionalQualityAcceptanceof

BuildingEngineering.Thequalityshallalsosatisfythespecialrequirements（ifany）placedbythe

equipmentordesign.

2Priortoinstallationofelectricalequipment，buildingengineeringshallmeetthefollowing

requirements：

1）Foundations人人文库andframesshallcomplywithdesignrequirementsandhavepassedacceptance.

2）Theindoorfoundationshallbecompletedandtheelevationmarkedonthewall.

3）Embeddedpartsandreservedholesshallcomplywithdesignrequirements.Embedded

electricalpipelinesshallnotbemissingorcloggedandembeddedpartsshallbesecured.

4）Plasteringanddecorationworksthatmightdamageorseverelycontaminateelectrical

equipmentshallbecompleted.

5）Thesiteshallbeclean.

6）Windowsanddoorsshallbeinstalled.

3Afterinstallationandbeforecommissioning，thebuildingengineeringshallmeetthefollowing

·4·

requirements：

1）Repairofdefectsanddecorationworksshallbecompleted.

2）Secondarygroutingandplasteringworksshallbecompleted.

3）Theventilationsystemforexplosionpreventionandexplosiveleakagecontrolsystemshall

complywithdesignrequirementsandoperateasexpected.

4）Worksthatcannotbeperformedormayjeopardizeoperationalsafetyaftertheequipmentis

energizedshallhavebeencompletedandpassedacceptance.

5）Luminaireshallhavebeenputintoservice.

3.0.7Exceptanchorbolts，allironfastenersandsupportsusedforequipmentinstallationshallbe

galvanized.

3.0.8Classificationofexplosivegasatmosphere，explosivedustatmosphereandfirehazardousareas

shallcomplywiththecurrentnationalstandardsGB50058CodeforDesignofElectricalInstallations

inExplosiveAtmospheresandGB50016CodeforFireProtectionDesignofBuildings.

Thetype，class，group，environmentalconditionsandspeciallabelsofexplosionproofelectrical

3.0.9-

equipmentshallcomplywithdesignrequirements.

Explosionproofelectricalequipmentshallhavean"Ex"labelandanameplatewhichindicates

3.0.10-

itstype，class，groupaswellastheexplosionproofcertificatenumber.

-专用

人人文库

·5·

4Installationofexplosion-proofelectricalequipment

4.1Generalrequirements

Installationofexplosionproofelectricalequipmentshallcomplywithcurrentnationalstandards

4.1.1-

GB3836.15：，and

ElectricalAtmospheres-Part15ElectricalInstallationDesignSelectionandErection

GB12476ElectricalApparatusforUseinthePresenceofCombustibleDustaswell.

Explosionproofelectricalequipmentshouldbeinstalledonsecuredmetallicsupports.

4.1.2-

Tighteningboltspossessingantilooseningdevicesshallbeusedforelectricalequipmentwithvibration.

-

Afterwiresofexplosionproofelectricalequipmentarefixedinsidetheterminalbox，the

4.1.3-

electricalclearanceandcreepagedistancebetweenbarelivepartsandclearancesbetweenbareliveparts

andmetallicenclosureshallnotbelessthanthevaluesspecifiedinAppendixAofthiscode.

4.1.4Cableentryshallbekeptintactandtheelasticsealwashershallbeofgoodsealingperformance

whencablesorconductorsareledtotheexplosionproofelectricalthroughthecableinlet.And

-

compressionelementsshallbefixedwithpropertoolsandthecableinletbesealedwell.Theelasticseal

washer，metallicgasketandsealsforothercableinletsshallbecompleteandsecuredtokeeptheinlets

sealed.专用

4.1.5Transparentplasticcomponentsandotherplasticcomponentsshallnotbewashedwithsolvent.

4.1.6Thebuttonofemergencyventilationshallbeinstalledinaneasilyaccessibleplaceandclearly

marked.

4.1.7Installationofluminaireshallcomplywiththefollowingrequirements：

1Thetype，modelandpowershallcomplywiththedesignandmanufacturer'stechnical

documentsandshallnotbechangedwithoutapproval.

Screwtypelampsshallbetighteningscreweduptoensuregoodcontactwithoutlooseness.

2-

3Outercoversoflampsshallbecompleteandtheboltsshallbetightened.

4.1.8Protectionofelectricalequipmentexposedtoexplosionhazardshallcomplywithdesign

requirements.

4.2Installationofflameproofelectricalequipment

4.2.1Beforeinstallation，flameproofelectricalequipmentshallbeinspectedinaccordancewiththe

followingrequirements：

1Thespecifications人人文库ofelectricalequipmentshallcomplywithdesignrequirementsandthe

nameplateandexplosionprooflabelshallbecorrectandclear.

-

2Theenclosureshallbefreeofcracksanddamages.

3Theflameproofstructureandclearanceshallmeettherequirements.

Theboltsconnectingjointsurfacesshallbecomplete，andthespringwashersandotheranti

4-

looseningdevicesshallbecomplete，intactandflat.

5Thesealinggasketsshallbecompleteandintact，freeofaginganddeformation，andcomply

withrequirementsinthemanufacturer'stechnicaldocuments.

6Transparentcomponentsshallbebright，clean，andfreeofdamages.

·6·

7Movingpartsshallbefreeofcollisionandfriction.

8Terminalboardsandinsulatedpartsshallbefreeofcracks.Terminalboxcoversshallbe

secured，andtheelectricalclearanceandcreepagedistanceshallcomplywithapplicablerequirements.

9Groundingsignsandgroundingboltsshallbeingoodcondition.

4.2.2Assemblyanddisassemblyofflameproofelectricalequipmentshallcomplywiththefollowing

requirements：

1Theflameproofsurfaceshallbeprotectedfromdamages.

2Theflameproofsurfaceshallbefreeofsandinclusionandmechanicaldamages.

Flameproofsurfaceswithoutelectroplatedorphosphatizedlayersmaybeappliedwithnon

3-

condensablelubricatinggreaseorantirustoil.Paintingisnotallowed.

-

Theflameproofsurfaceshallberustfreewhenassembling.

4-

5Boltsusedforfasteningtheflameproofjointsurfacesshallnotbechangedwithoutapprovaland

springwashersshallbecomplete.

6Forflameproofstructureswiththreads，theminimumnumberofengagingthreadsand

minimumengagingdepthshallcomplywithrequirementssetinTable4.2.2.

Table4.2.2Minimumnumberofengagingthreadsandminimumengaging

depthforthreadedflameproofstructure

Minimumnumberofengagingthreads

NetvolumeofenclosureVMinimumengagingdepth

（cm3）（mm）ⅡAandⅡB专用ⅡC

V≤1005.0

Twicethenumberoftestthreads，

100＜V≤20009.06

butatleastsix

V＞200012.5

4.2.3Foraflameproofmotor，thespacingsbetweentheshaftandshaftboreandbetweenthefanand

outercovershallbeuniform，withoutcontactorfrictioninnormaloperation.

4.2.4Forflameproofelectricalequipmentproducingsparksorarcsduringnormaloperation，the

electricalinterlockshallfunctionreliably.Itisnotallowedtoremovetheenclosurewhentheequipment

isenergizedorenergizetheequipmentwhentheenclosurehasbeenremoved.Fortheenclosure

fasteningwithbolts，thenoticeboardof"Removetheenclosureafterpoweroff"shallbecheckedifitis

inplaceandingoodcondition.

4.2.5Inspectionandinstallationofflameprooftypeplugsshallcomplywiththefollowingrequirements：

1Whentheplugisinserted，thecontactconnectedtogroundorneutralshallbeconnectedfirst，

andwhentheplugispulledout，themaincontactshallbedisconnectedfirst.

2Theplug人人文库shallbeinsertedorpulledoutwhentheswitchisopen，andtheswitchcanbeclosed

onlyaftertheplugisinserted.

Theslowreactiondeviceusedforpreventingsuddenpulloutshallfunctionreliablyandnever

3-

becomeloose.

4.3Installationofincreasedsafetyandtypeofprotection"n"

4.3.1Beforeinstallation，electricalequipmentofincreasedsafetytypeandwith"n"protectiontype

shallbeinspectedinaccordancewiththefollowingrequirements：

1Thetypeandspecificationsshallcomplywithdesignrequirements，andthenameplateand

·7·

explosionprooflabelshallbecorrectandclear.

-

2Theenclosureandtransparentpartsshallbefreeofcracksanddamagesandhaveaprotection

classasrequired.

Boltsusedforsecuringtheequipmentshallbeprovidedwithantilooseningmeasures，andshall

3-

notbecomelooseorrusted.Thecoveroftheterminalboxshallbesecured.

4Protectiondevicesandaccessoriesshallbecompleteandingoodcondition.

4.4Installationofpressurization"p"

4.4.1Beforeinstallation，electricalequipmentwithpositivepressure，outercoverand"p"protection

shallbeinspectedinaccordancewiththefollowingrequirements：

1Thetypeandspecificationsshallcomplywithdesignrequirements，andthenameplateand

explosionprooflabelshallbecorrectandclear.

-

2Theenclosureandtransparentpartsshallbefreeofcracksanddamages.

Boltsusedforsecuringtheequipmentshallbeprovidedwithantilooseningmeasures，andshall

3-

notbecomelooseorrusted.Thecoveroftheterminalboxshallbesecured.

4Protectiondevicesandaccessoriesshallbecompleteandingoodcondition.

5Thesealinggasketshallbecompleteandintact，freeofaginganddeformation，andcomplywith

applicabletechnicalrequirements.

4.4.2Theairorgasflowingintotheventilation，chargingsystemand专用electricalequipmentshallbe

clearofexplosivemixturesorotherhazardousmaterials.

4.4.3Gasesexhaustedduringventilationshouldnotbedischargedintoanexplosiveatmosphere.

Whensuchgasesaredischargedintoazone2area，measuresshallbetakentopreventsparksandheated

particlesbeingblownoutfromtheelectricalequipmentandplenumventilationsystem.

4.4.4Theelectricalinterlockfortheventilationandchargingsystemshallbeenergizedafter

ventilationisstarted，anddeenergizedbeforeventilationisshutdown.Beforetheelectricalequipment

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isenergized，thevolumeofprotectivegasesinsidetheenclosureshallnotbelessthanthesumofthe

minimumvolumeforreplacementspecifiedinthemanufacturer'stechnicaldocumentsandfivetimesthe

volumeofconnectedduct.

4.4.5Duringoperation，thewindpressureandgaspressureinsidetheelectricalequipment，ventilation

andchargingsystemshallcomplywithdesignrequirements.

4.4.6Sparksorarcsproducedduringnormaloperationofelectricalequipmentwithpressurization"p"

shallnotbeblownoutfromtheequipmentthroughgapsorairoutlets.

4.4.7Theventilation人人文库ductshallbesealedwell.

4.5Installationofoilimmersion"o"

4.5.1Beforeinstallation，theoilimmersedtypeelectricalequipmentwith"o"protectionshallbe

inspectedinaccordancewiththefollowingrequirements：

Thetypeandspecificationsshallmeetdesignrequirements，andthenameplateandexplosion

1-

prooflabelshallbecorrectandclear.

2Theenclosureshallbefreeofcracksanddamages.

3Theoiltankandoillevelgaugeshallbefreeofcracksandleakage.Theoillevelshallbewithin

thespecifiedlevelrange.

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4Theoiloutletandairoutletshallbeclearofsundries.

4.5.2Oilimmersedtypeelectricalequipmentwith"o"protectionshallbeinstalledverticallywithan

inclinationnogreaterthan5°.

4.5.3Themaximumtemperatureriseofoilsurfaceinoilimmersedtypeelectricalequipmentwith"o"

protectionshallnotexceedthevaluesspecifiedinTable4.5.3.

Table4.5.3Maximumpermissibletemperatureriseofoilsurfaceinoilimmersedtype

electricalequipmentwith"o"protection

MaximumpermissibletemperatureriseMaximumpermissibletemperaturerise

TemperatureclassTemperatureclass

ofoilsurface（℃）ofoilsurface（℃）

T1，T2，T3，T4andT560T640

4.6Installationofintrinsicsafety"i"

4.6.1Beforeinstallation，electricalequipmentwithintrinsicsafety"i"protectionshallbeinspectedin

accordancewiththefollowingrequirements：

Thetypeandspecificationsshallmeetdesignrequirements，andthenameplateandexplosion

1-

prooflabelshallbecorrectandclear.

2Theenclosureshallbefreeofcracksanddamages.

3Thenameplatesofelectricalequipmentwithintrinsicsafety"i"protectionandassociated

electricalequipmentshallhavean"Ex"label，theexplosionproofcertificate专用number，andrelated

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electricalparameters.Combinationofelectricalequipmentwithintrinsicsafety"i"protectionand

associatedelectricalequipmentshallconformtotheprovisionsinthecurrentnationalstandard

GB3836.18：.

ExplosiveAtmospheres-Part18IntrinsicallySafeElectricalSystems

4Allparts，elements，andcircuitsoftheelectricalequipmentshallbeconnectedreliablyandhave

asatisfactoryperformance.

4.6.2Thepowertransformerofassociatedelectricalequipmentshallcomplywiththefollowing

requirements：

1Theshieldbetweenthecoreandwindingsofthetransformershallbereliablygroundedatonly

onepoint.

2Theratedcurrentofthefuseforthepowertransformerdirectlyconnectedwithanexternal

powersupplyshallcomplywithdesignrequirements.

4.6.3Thetypeandspecificationsofthebatteryforseparatelyenergizedelectricalequipmentwith

intrinsicsafety"i"protectionshallbeconsistentwiththosespecifiedinthenameplate.Batteriesofother

typesandspecificationsarenotallowed.

4.6.4Thetype人人文库，specifications，lengthandrelatedparametersofconductorsorcablesusedfor

connectingelectricalequipmentwithintrinsicsafety"i"protectionandassociatedelectricalequipment

shallcomplywithdesignrequirements.

4.7Installationoftypeofdust-ex

Beforeinstallation，dustignitionproofelectricalequipmentshallbeinspectedinaccordancewith

4.7.1-

thefollowingrequirements：

Theexplosionprooflabel，degreeofprotectionofenclosure，aswellasthetemperatureclass

1-

shallbeappropriatetotheintendedexplosivedustatmosphere.

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Thetypeandspecificationsshallmeetdesignrequirements，andthenameplateandexplosion

2-

prooflabelshallbecorrectandclear.

3Theenclosureshallbesmooth，freeofcracks，damages，anddents，andhaveadesiredstrength.

4Boltsusedforsecuringtheequipmentshallnotbecomelooseorrusted.

5Enclosurejointsurfacesshallbesecuredandsealed，andthesealwashersshallremainintact.

Thespacebetweentherotatingshaftandshaftboreshallbehermeticallysealedfordustprevention.

Transparentpartsshallbefreeofcracksanddamages.

4.7.2Theelectricalequipmentshallbefixedfirmly，wiredcorrectlyandcontactwell.Theventilation

ductshallnotbeblocked.Andtheelectricalclearanceandcreepagedistanceshallmeettechnical

requirementsoftheequipment.

4.7.3Theenclosure，cableentryandsealingperformanceofelectricalequipmentshallnotbedamaged

duringinstallation.

Theclassandgroupofexplosionproofelectricalequipmentshallnotbelowerthanthoseofthe

4.7.4-

explosivegasatmospherewheretheelectricalequipmentisinstalled，andshallcomplywithdesign

requirements.Theelectricalequipmentinstalledinexplosivedustatmosphereshallbeprotectedwith

measurestopreventfirehazardresultingfromcombustibledustonhotsurfaces.Themaximumsurface

temperatureofClassⅢelectricalequipmentshallbedeterminedinaccordancewiththecurrentnational

applicablestandards.Theelectricalequipmentshallbeconstructedsuchthatitsexplosionproof

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performancewillnotbeimpairedinspecifiedoperationconditions.专用

Afterinstallationofdustignitionproofelectricalequipment，theprotectivedevicesshallbe

4.7.5-

testedandcommissionedinaccordancewiththemanufacturer'stechnicaldocuments.

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