40 34-ST-25-19 RMA 3000 Remote Meter Assemblies User Manual Release: 1
6/04
IEC Methods of
Protection
The following table summarizes available methods of protection for use in given
locations.
Protection Concept Designation Permitted Use Principle
Flameproof d Zone 1 & 2 Contains explosion and
quenches flame.
Intrinsic Safety ia Zone 0, 1 & 2 Limits energy of sparks under 2
faults.
ib Zone 1 & 2 Limits energy of sparks under
1 fault
Pressurized p Zone 1 Keeps flammable gases out.
Encapsulation m Zone 1 & 2 Keeps flammable gases out.
Increased Safety e Zone 1 & 2 No arcs, sparks or hot
surface.
Powder Filled q Zone 1 & 2 Contains explosion and
quenches flame.
Oil Immersion o Zone 1 & 2 Keeps flammable gases out.
Non-sparking nA Zone 2 No arcs, sparks or hot
surfaces under normal
conditions.
Enclosed Break nC Zone 2 Contains explosion and
quenches flame.
Limited Energy nA Zone 2 Limits energy of sparks and
surface temperature under
normal conditions.
Restricted Breathing nR Zone 2 Keeps flammable gases out.
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