Wago 750-333 PROFIBUS DP/V1 FIELD BUSCOUPLER 12 MBaud 750-333 Datenbogen

Explosive Environments •  137

2001-02-27

Explosive areas resulting from combustible gases, fumes or mist:

•  Zone 0 areas are subject to an explosive atmosphere

(> 1000 h /year) continuously or for extended periods.

•  Zone 1 areas can expect the occasional occurrence of an explosive atmos-

phere (> 10 h 

≤ 1000 h /year).

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

atmosphere (> 0 h 

≤ 10 h /year).

Explosive areas subject to air-borne dust:

•  Zone 20 areas are subject to an explosive atmosphere

(> 1000 h /year) continuously or for extended periods.

•  Zone 21 areas can expect the occasional occurrence of an explosive atmos-

phere (> 10 h 

≤ 1000 h /year).

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

atmosphere (> 0 h 

≤ 10 h /year).

In addition, the electrical components for explosive areas are subdivided into
two groups:

Group I:

Group I includes electrical components for use in fire-damp
mine structures.

Group II:

Group II includes electrical components for use in all other
explosive environments. The group is further subdivided by
pertinent combustible gasesin 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

Explosion group

I

IIA

IIB

IIC

Gases

Methane

Propane

Ethylene

Hydrogen

Ignition energy (mWs) 0,28

0,25

0,082

0,016