October 2012 Electrical Apparatus

October 2012 Electrical Apparatus

This is a summary of the Electrical Apparatus October 2012 featured technical article,  by Richard L. Nailen, P.E.     

A new edition of NFPA Standard 70, the National Electrical Code is coming late next year. If past Code cycles are any guide, some of both Proposals and Comments will have been rejected on grounds that they set forth some design criterion.

But the designer’s essential task is to decide how to comply within financial, material, or manufacturing constraints. The process is far beyond, and unrelated to, the mere selection of a number from some table. In this sense, the National Electrical Code is clearly a design specification. “Design,” according to one dictionary, is “to formulate a plan for . . . to plan out . . . to create or contrive for a particular purpose or effect . . . to have a goal or purpose in mind.” Compliance with the NEC appears to fit such a definition. Certainly the Code has a stated “goal or purpose.” Article 90.1 defines it as “the practical safeguarding of persons and property from hazards arising from the use of electricity.”

Some specific Code provisions use wording typical of design specifications. We outline more than a dozen of them in this article.

In addition, other provisions require equipment manufacturers to provide certain design features in their products. This article provides specific examples.

Conflict among inspecting authorities is one further complication. But whenever compliance with a standard involves design decisions, that standard can be considered a “design specification”—a document that sets forth design requirements—whether or not it prescribes all the details of method.

The National Electrical Code not a “design specification”? Of course it is. It has to be. It specifies conditions that can only result from design.

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