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Bigger Than Ever: The U.S. National Electrical Code (NEC)

What electrical installation practices can be permitted only in a "supervised industrial installation"? The definition of such an environment has remained tucked away in certain NEC sections, of which 240.2 is one, and is associated with one of the Code's more significant long-running controversies.

Debate began years ago over the basic nature of the NEC. The argument grew especially heated with the growth of large petrochemical industries in which electric power apparatus and circuitry were essential to round-the-clock process operation. Cable tray, direct burial, and operating voltages as high as 14,400 were far outside the typical electrician's concern for 120 volt residential wiring, or conduit installation in commercial buildings.

Whereas the typical residential or commercial electrical system, is used by individuals untrained in electrical technology, or equipped to supervise, maintain, or repair apparatus or circuits, the large industrial facility normally has an operating and maintenance staff knowledgeable in such matters.

Engineering groups therefore began arguing for a separate "industrial" code, slanted towards the differing needs of installations in manufacturing facilities, that would enable them to use their expertise to assure safety without applying many NEC provisions that suited only premises occupied by untrained citizens.

Although the movement to establish an entirely separate code has never borne fruit, today's NEC does contain many notes, exceptions, and references to permit or suggest practices outside the norms in situations where electrical systems and apparatus are "installed and maintained in industrial settings by trained workers." Similarly, certain practices not normally permitted by the NEC may be allowable "under engineering supervision" (see, for example, Exception No. 4 to Section 310.4). One of the more detailed exceptions appears in Section 314.50 concerning electric enclosures intended for personnel entry: "Where electric enclosures...are part of an industrial wiring system operating under conditions of maintenance and supervision that ensure only qualified persons monitor and supervise the system, they shall be permitted to be designed and installed in accordance with appropriate engineering practice..."

So -- "Why not an industrial electrical code?" asked one headline decades ago. Process industries in Canada, where many large petrochemical projects are under development, have begun to act on that question. With the aid of the Canadian Standards Association, such users launched the "OBIEC" project late in 2003. The acronym stands for "Objective Based Industrial Electrical Code."

The document is in the initial drafting stage, with completion scheduled for the end of 2005. It will be based on defined objectives of operating safety, leaving many of the detailed requirements ("prescribed" by existing codes) up to the system or project designer. The major references will be IEEE standards.

Only "qualified" (as determined by regulatory agencies in each Canadian province) industrial firms will be allowed to use the OBIEC procedures. Regular audits will be required for maintaining that qualification. An accompanying "safety management system" will establish the regulatory capability.

Much work remains to be done. Will such an alternative code someday be adopted in the United States? That appears unlikely, but firm predictions may be unwise.

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