A Comparison of IEC & NEC for specifying Hazardous Locations

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Comparing IEC & NEC for classifying hazardous locations is not easily accomplished. They are both good systems and were developed independently of each other. Each has its own approach to area classification and each has its own advocates and approval organizations. Neither system has been proven to be safer than the other. Generally, cost comparisons of the two are inconclusive. Currently the IEC system has wide use throughout most of the world (except in the U.S.) in the chemical and petrochemical industries. With oil activity in scores of different countries, the IEC standardized approach suits these industries well.The Class/Division method is the dominant method used in the U.S. and via the NEC® is meant to serve all hazardous areas from oil to sewage treatment to paint spray locations to everyday gasstations. The Class/Division method is very straight forward, leaves little doubt as to a classification and what electrical material can or cannot be used. Learning the IEC method is not as easy, but probably offers more choices as how to handle a particular application. The attached document is intended to provide a comparison.