Page 616 - Wago_PCB_TerminalBlocksConnectors_Volume2_2015_US
P. 616
General Technical Information
13 on Electrical Equipment Used in Hazardous Areas (continued)
614
Hazardous environments are areas in mixed ratios such that excessive high tem- According to EN 1127-1 and other stan-
which the atmosphere may become perature, arcs or sparks may cause an dards, hazardous areas are divided into
explosive. An explosive atmosphere is a explosion. “Zones” based on the likelihood of an
mixture of flammable substances in the explosive atmosphere occurring:
form of gases, vapors or mixtures with air
under atmospheric conditions in critically
1 Hazardous areas resulting from flam-
mable gases, vapors or mist
Zone 0
Areas in which a hazardous, potentially
explosive atmosphere is present perma-
nently, for long periods or frequently.
Zone 2
Zone 1
Areas in which hazardous, potentially
explosive atmospheres are likely to
occur “occasionally” during normal
Zone 0 operation.
Zone 1
Zone 1 Zone 2
Areas in which hazardous, potentially
explosive atmospheres are likely to
Zone 0 Zone 0 occur “rarely” or “short-term” during
normal operation.
2 Hazardous areas resulting from com-
bustible dust
Zone 20
Area in which a hazardous, potentially
explosive atmosphere is continuously
present, or present over an extended
Zone 22
period or frequently in the form of a dust
cloud. Dust deposits in common or exces-
sive thickness can be formed. Dust depos-
its alone do not constitute a Zone 20.
Zone 21
Area in which a hazard, potentially
explosive atmosphere can occasionally
occur in the form of a dust cloud during
normal operation. Deposits or layers of
Zone 21 dust are generally present.
Zone 20
Zone 22
Areas in which an explosive dusty atmo-
sphere is not likely to occur during nor-
mal operation and, if it occurs, will only
exist for a “short period”, or in which
accumulations or layers of flammable
dust are present.
