NEMA Publishes ANSI/NEMA OS 3 - Selection & Installation Guidelines for Electrical Outlet Boxes
March 28, 2008 // Published as a news service by IHS
The National Electrical Manufacturers Association (NEMA) 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 perspective on appropriate selection and installation criteria, based on the design and intended use of the product.
This edition includes:
- Revisions to the summary table for support of luminaires, fixtures and other products.
- A 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.
This edition also removes device boxes as being capable of supporting products weighing six to 49 pounds in or on walls.
According to David Kendall, chairman of the NEMA Outlet and Switch Box Section that developed the standard, there may be no other component of the 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," said Kendall.
"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."
Source: National Electrical Manufacturers Association (NEMA).