Electrical area classification definitions, applications and alternatives

A review is presented of the definitions of Class I, Class II, and Class III locations. A discussion is presented of the differences between Division 1 and 2 locations along with an explanation of the seven groups, A, B, C, D, E, F and G. An explanation of how National Electrical Manufacturer´s Association (NEMA) enclosures are to be applied in classified areas is given. Other closely related standards, the National Fire Protection Association (NFPA)-496 `Purged and Pressurized Enclosures for Electrical Equipment´ and Instrument Society of America (ISA-RP) 12.6 `Installation of Intrinsically Safe Systems for Hazardous (Classified) Locations´, are briefly discussed as to how they can provide alternatives for applications of electrical equipment in classified locations. An application guide is presented along with a partial cross-reference between the National Electrical Code (NEC) and International Electrotechnical Commission (IEC)/European Committee for Electrotechnical Standardization (CENELEC) standards