March 19, 2008 - Rosslyn VA: The National Electrical Manufacturers Association (NEMA) has published ANSI/NEMA OS 3-2007 Selection and Installation Guidelines for Electrical Outlet Boxes. It provides designers, installers, and inspectors with the outlet box industry’s perspective on appropriate selection and installation criteria, based on the design and intended use of the product.

According to David Kendall, chairman of the NEMA Outlet and Switch Box Section that developed the standard, there may be no other component of our electrical distribution system that serves more purposes than electrical outlet boxes.

“They give access to wiring, connect raceway systems, provide mechanical protection, and prevent persons from contacting energized parts of the electrical system,” Kendall said. “Through these guidelines, industry seeks to develop a closer liaison with installers and electrical inspectors, by providing education and understanding of proper application and installation of boxes. This understanding ensures that the concerns and challenges that face manufacturers, contractors, and Authorities Having Jurisdiction are addressed.”

This edition includes revisions to the summary table for support of luminaires, fixtures, and other products; a new table of fan support weight ratings; a list of weight classifications for ceiling-suspended fan boxes; permitted markings on boxes for fan support; rewritten guidelines for boxes and covers in wet and damp locations and adverse environments; revisions of minimum fitting thread engagement with threaded entries for threaded conduit or fittings, to 3-1/2 threads; and removes device boxes as being capable of supporting products weighing 6–49 pounds in or on walls.

An electronic copy of ANSI/NEMA OS 3-2007 may be downloaded at no charge or a hard copy may be purchased for $75, by visiting NEMA’s website, or by contacting IHS at 800-854-7179 (within the U.S.), 303-397-7956 (international), 303-397-2740 (fax), or on the Web.