Use in Hazardous Environments
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Classifications Meeting the NEC 500
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
9.4 Classifications Meeting the NEC 500
The following classifications as defined in article 500 and 505 of the National
Electric Code (NEC) are valid for North America.
9.4.1 Divisions
The "Divisions" describe the degree of probability of whatever type of
dangerous situation occurring. Here the following assignments apply:
Tab. 9-6: Divisions
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).
9.4.2 Explosion Protection Groups
Electrical components for explosion endangered areas are subdivided in three
danger categories:
Tab. 9-7: Explosion Protection Groups
Danger category
Sub-group
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
