INSTALLATION AND OPERATING PRECAUTIONS FOR TIIS
FLAMEPROOF EQUIPMENT
ApparatusCertiedUnderTechnicalCriteria
(IEC-compatible Standards)
1. General
The following describes precautions on electrical
apparatusofameproofconstruction(hereinafterreferred
toasameproofapparatus)inexplosion-protected
apparatus.
FollowingtheLabourSafetyandHealthLawsofJapan,
ameproofapparatusissubjectedtotypeteststomeet
either the technical criteria for explosionproof electrical
machineryandequipment(standardsnoticationno.
556fromtheJapaneseMinistryofLabour)(hereinafter
referred to as technical criteria), in conformity with the IEC
Standards,orthe“RecommendedPracticeforExplosion-
ProtectedElectricalInstallationsinGeneralIndustries,”
publishedin1979.Thesecertiedapparatuscanbeused
inhazardouslocationswhereexplosiveorinammable
gases or vapours may be present.
Certiedapparatusincludesacerticationlabelandan
equipmentnameplatewiththespecicationsnecessary
for explosion requirements as well as precautions on
explosionprotection.Pleaseconrmtheseprecautionary
itemsandusethemtomeetspecicationrequirements.
For electrical wiring and maintenance servicing, please
referto“InternalWiringRules”intheElectricalInstallation
TechnicalStandardsaswellas“USER’SGUIDELINES
for Electrical Installations for Explosive Gas Atmospheres
inGeneralIndustry,”publishedin1994.
Tomeetameproofrequirements,equipmentthatcanbe
termed“ameproof”must:
(1) BecertiedbyaJapanesepublicauthorityin
accordance with the Labour Safety and Health
LawsofJapanandhaveacerticationlabelinan
appropriate location on its case, and
(2) Beusedincompliancewiththespecicationsmarked
onitscerticationlabel,equipmentnameplateand
precautionary information furnished.
2. Electrical Apparatus of
Flameproof Type of Explosion-
Protected Construction
Electricalapparatuswhichisofameproofconstruction
issubjectedtoatypetestandcertiedbytheJapanese
Ministry of Labour aiming at preventing explosion caused
by electrical apparatus in a factory or any location where
inammablegasesorvapoursmaybepresent.The
ameproofconstructionisofcompletelyenclosedtype
and its enclosure shall endure explosive pressures in
cases where explosive gases or vapours entering the
enclosure cause explosion. In addition, the enclosure
constructionshallbesuchthatamecausedbyexplosion
does not ignite gases or vapours outside the enclosure.
Inthismanual,theword"ameproof"isappliedto
theameproofequipmentcombinedwiththetypesof
protection"e","o","i",and"d"aswellasameproof
equipment.
3. Terminology
(1) Enclosure
An outer shell of an electrical apparatus, which encloses
livepartsandthusisneededtocongureexplosion-
protected construction.
(2) Shroud
A component part which is so designed that the fastening
of joint surfaces cannot be loosened unless a special tool
is used.
(3) Enclosure internal volume
This is indicated by:— the total internal volume of the
ameproofenclosureminusthevolumeoftheinternal
components essential to equipment functions.
(4) Path length of joint surface
On a joint surface, the length of the shortest path through
whichameowsfromtheinsidetooutsideofthe
ameproofenclosure.Thisdenitioncannotbeappliedto
threaded joints.
(5) Gaps between joint surfaces
The physical distance between two mating surfaces,
or differences in diameters if the mating surfaces are
cylindrical.
Note: The permissible sizes of gaps between joint surfaces,
the path length of a joint surface and the number of joint
threads are determined by such factors as the enclosure’s
internal volume, joint and mating surface construction,
andtheexplosionclassicationofthespeciedgasesand
vapours.