This standard applies to:
–a) Apparatus or parts of apparatus in Class I, II, or III, Division 1 locations ; a
–b) Those parts of apparatus located outside of the Class I, II, or III, Division 1 location having a design and construction that may influence the intrinsic safety of an electrical circuit within the Class I, II, or III, Division 1 location;
–c) Apparatus or parts of apparatus in Class I, Zone 0 or 1, Groups IIA, IIB, and IIC locations;
–d) Those parts of apparatus located outside of the Class I, Zone 0 and 1, Groups IIA, IIB, or IIC location having a design and construction that may influence the intrinsic safety of an electrical circuit within the Class I, Zone 0 and 1, Group IIA, IIB, or IIC location. Section 500-3(a) of ANSI/NFPA 70-1987, National Electrical Code, states that equipment that has been a approved for a Division 1 location shall be permitted in a Division 2 location of the same class and group.
These requirements are based on consideration of ignition in locations made hazardous by the presence of flammable or combustible material under normal atmospheric conditions.