The net effect: a detailed impact analysis of a three-level classification system on the electrical industry

Abstract

The 1993 National Electrical Code (NEC) cycle contained a very controversial proposal-to change the area classification system for Class I hazardous (classified) locations from a two-division to a three-division system. In general, the user representatives on Code Making Panel 14 supported this change, but the other representatives did not. Similarly, in 1987, a number of Western Canadian users and consultants began to develop a real awareness of the International Electrotechnical Commission (IEC) System for classified locations. Since that time, this group of Canadians has spent significant time researching the IEC System. They have developed and implemented a plan to make the necessary changes to the Canadian electrical installation codes and standards to allow Canadian users access to IEC technology. The change to permit use of the international classification system in North America has been controversial. The authors' approach to this paper was to assume that both the North American and the IEC systems for classified locations have been proven to be safe. The paper disregards the unsubstantiated claims and counter-claims made by those on both sides of the issue. Clearly, there are differences between the two systems, and this paper explores these differences. The paper attempts to emphasize the differences between the two systems to allow the readers to draw their own conclusions as to which system is best for their applications. A comparison is made between a typical North American installation and a typical IEC installation to illustrate the impact of change to a three-division system.