WAGO 750-306 Technical Description page 140

140 • Application in Explosive Environments
Classification Meeting CENELEC and IEC
Explosive Areas Resulting from Gases, Fumes or Mist:
• Zone 0 areas are subject to an explosive atmosphere
• Zone 1 areas can expect the occasional occurrence of an explosive at-
• Zone 2 areas can expect the rare or short-term occurrence of an explo-
Explosive Areas Subject to Air-borne Dust:
• Zone 20 areas are subject to an explosive atmosphere
• Zone 21 areas can expect the occasional occurrence of an explosive at-
• Zone 22 areas can expect the rare or short-term occurrence of an explo-
6.3.2 Explosion Protection Group
In addition, the electrical components for explosive areas are subdivided
into two groups:
Group I:
Group II:
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.
(> 1000 h /year) continuously or for extended periods.
mosphere (> 10 h ≤ 1000 h /year).
sive atmosphere (> 0 h ≤ 10 h /year).
(> 1000 h /year) continuously or for extended periods.
mosphere (> 10 h ≤ 1000 h /year).
sive atmosphere (> 0 h ≤ 10 h /year).
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 differ-
ent 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
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