Explosive Areas Subject To Air-Borne Dust; Explosion Protection Group - WAGO 750 Series Manual

214 • Use in Hazardous 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
• Zone 2 areas can expect the rare or short-term occurrence of an explosive

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
• Zone 22 areas can expect the rare or short-term occurrence of an explosive

9.3.2 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)
(> 1000 h /year) continuously or for extended periods.
atmosphere (> 10 h ≤ 1000 h /year).
atmosphere (> 0 h ≤ 10 h /year).
(> 1000 h /year) continuously or for extended periods.
atmosphere (> 10 h ≤ 1000 h /year).
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
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
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