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Use in Hazardous Environments
Classification Meeting CENELEC and IEC
6.3.2 Explosion Protection Group
In addition, the electrical components for explosive areas are subdivided into
two groups:
Group I:
Group II:
Tab. 6-1: Minimal ignition energy of representative types of gases
Minimal Ignition Energy of Representative Types of Gases
Explosion group
Gases
Ignition energy (µJ)
Hydrogen being commonly encountered in chemical plants, frequently the
explosion group IIC is requested for maximum safety.
Group I includes electrical components for use in fire-damp
endangered mine structures.
Group II includes electrical components for use in all other
explosive environments. This group is further subdivided by
pertinent combustible gases in the environment.
Subdivision IIA, IIB and IIC takes into account that
different materials/substances/gases have various ignition
energy characteristic values. For this reason the three sub-
groups are assigned representative types of gases:
IIA – Propane
IIB – Ethylene
IIC – Hydrogen
I
Methane
280
IIA
IIB
Propane
Ethylene
250
82
WAGO-I/O-SYSTEM 750
IIC
Hydrogen
16
Bus System
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