North American zones: rethinking hazardous location design

Abstract

Changes to the Canadian Electrical Code (CEC) (1998) and National Electrical Code (NEC) (1996 and 1998), while progressive, are only first steps. The updates allow the use of the International Electrotechnical Commission (IEC) classification system and products. For the purposes of this article, the CEC is used as a starting point. This article examines a combination of the "best practices" from Canada, Europe, and the United States, which relate to petrochemical installations. The optimal design for a facility is not as simple as exchanging products. It is more like rethinking conventional design practices. Area classification, wiring methods, equipment placement, and product design are discussed. The right combination of the two wiring systems is not as simple as applying IEC products to a class-division-type design. While the modular style of IEC products may offer greater flexibility, traditional North American products are readily available and more familiar to most designers. However, since North America, and perhaps to a greater extent Canada, is in the unique position of taking advantage of the best of both systems, the best design is likely to be found in a combination of the two. In Alberta, Canada, regulators granted permission for the use of products approved to standards other than CSA International in selected facilities to accommodate the "combination" design.