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Application in Explosive Environments
Classifications meeting the NEC 500
WAGO-I/O-SYSTEM 750
Modular I/O-System
Ex-1.4 Classifications meeting the NEC 500
The following classifications according to NEC 500 (National Electric Code)
are valid for North America.
Ex-1.4.1 Divisions
The "Divisions" describe the degree of probability of whatever type of
dangerous situation occurring. Here the following assignments apply:
Explosion endangered areas due to combustible gases, fumes, mist and dust:
Division 1
encompasses areas in which explosive atmospheres are to be expected
occasionally (> 10 h
≤
1000 h /year) as well as continuously and long-term
(> 1000 h /year).
Division 2
encompasses areas in which explosive atmospheres can be expected rarely
and short-term (>0 h
≤
10 h /year).
Ex-1.4.2 Explosion protection groups
Electrical components for explosion endangered areas are subdivided in three
danger categories:
Class I (gases and fumes):
Group A (Acetylene)
Group B (Hydrogen)
Group C (Ethylene)
Group D (Methane)
Class II (dust):
Group E (Metal dust)
Group F (Coal dust)
Group G (Flour, starch and cereal dust)
Class III (fibers):
No sub-groups
