Technical data

Application in Explosive Environments • 73
Classification Meeting CENELEC and IEC
WAGO-I/O-SYSTEM 750
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6.3.5 Types of Ignition Protection
Ignition protection defines the special measures to be taken for electrical com-
ponents in order to prevent the ignition of surrounding explosive atmospheres.
For this reason a differentiation is made between the following types of igni-
tion protection:
Identifi-
cation
CENELEC Standard IEC Stan-
dard
Explanation Application
EEx o EN 50 015 IEC 79-6 Oil encapsulation Zone 1 + 2
EEx p EN 50 016 IEC 79-2 Overpressure encap-
sulation
Zone 1 + 2
EEx q EN 50 017 IEC 79-5 Sand encapsulation Zone 1 + 2
EEx d EN 50 018 IEC 79-1 Pressure resistant
encapsulation
Zone 1 + 2
EEx e EN 50 019 IEC 79-7 Increased safety Zone 1 + 2
EEx m EN 50 028 IEC 79-18 Cast encapsulation Zone 1 + 2
EEx i EN 50 020 (unit)
EN 50 039 (system)
IEC 79-11 Intrinsic safety Zone 0 + 1 + 2
EEx n EN 50 021 IEC 79-15 Electrical components
for zone 2 (see below)
Zone 2
Ignition protection “n" describes exclusively the use of explosion protected
electrical components in zone 2. This zone encompasses areas where explo-
sive atmospheres can only be expected to occur rarely or short-term. It repre-
sents the transition between the area of zone 1, which requires an explosion
protection and safe area in which for instance welding is allowed at any time.
Regulations covering these electrical components are being prepared on a
world-wide scale. The standard EN 50 021 allows electrical component manu-
facturers to obtain certificates from the corresponding authorities for instance
KEMA in the Netherlands or the PTB in Germany, certifying that the tested
components meet the above mentioned standards draft.
Type “n” ignition protection additionally requires electrical components to be
marked with the following extended identification:
· A – non spark generating (function modules without relay /without swit-
ches)
· AC – spark generating, contacts protected by seals (function modules with
relays / without switches)
· L – limited energy (function modules with switch)
Further information
For more detailed information please refer to the national and/or international
standards, directives and regulations!