Classifications Meeting The Nec 500 - WAGO 750-306 Technical Description

144 • Application in Explosive Environments

Classifications Meeting the NEC 500

6.4 Classifications Meeting the NEC 500
The following classifications according to NEC 500 (National Electric
Code) are valid for North America.
6.4.1 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
Division 2
6.4.2 Explosion Protection Groups
Electrical components for explosion endangered areas are subdivided in
three danger categories:
Class I (gases and fumes):
Class II (dust):
Class III (fibers):
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).
Encompasses areas in which explosive atmospheres can be expected rarely
and short-term (>0 h ≤ 10 h /year).
Group A (Acetylene)
Group B (Hydrogen)
Group C (Ethylene)
Group D (Methane)
Group E (Metal dust)
Group F (Coal dust)
Group G (Flour, starch and cereal dust)
No sub-groups
WAGO-I/O-SYSTEM 750
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