The US Occupational Safety and Health Administration (OSHA) published the final rule of its Subpart S revisions on Feb 14, 2007; it revises OSHA’s standard for existing electrical installations, which is contained in 1910.302 through 1910.308 of Subpart S with relevant definitions in 1910.399.

This is the first revision to OSHA’s general industry electrical standard in 25 years. OSHA’s general industry electrical safety regulations will now include the following:

A basis on the 2002 National Electrical Code and NFPA 70E-2000, Standard for Electrical Safety Requirements for Employee Workplaces (the previous version of Subpart S referenced the 1971 NEC and 1979 edition of NFPA 70E)

  • Acceptance of the zone system of classifying (hazardous) locations as an alternative to the traditional class-division system
  • Expanded requirements for GFCI protection of temporary wiring used for maintenance and repair purposes
  • Temporary wiring rules for carnivals and similar purposes

This revision’s purpose is to harmonize two different sets of OSHA electrical safety regulations for workplaces: OSHA 29 CFR 1926, Construction Industry Standards, Subpart K—Electrical (these cover installation of new electrical systems); and OSHA 29 CFR 1910, General Industry Standards, Subpart S—Electrical (these cover maintenance and repairs on existing electrical systems).

Electrical contractors are required to follow both sets of OSHA safety regulations, depending on what type of work they’re doing: CFR 1926 covers new construction, and CFR 1910 covers maintenance work. The two standards are similar, but not quite matching, which often causes confusion in the field. The revision of Subpart S will bring the two sets of mandatory OSHA safety regulations closer together but not harmonize them completely.

The OSHA regulatory process is slow and cumbersome, and the rulemaking that just ended began in April 2004. This is why the “new” Subpart S doesn’t reference either the 2005 NEC or NFPA 70E-2004, but instead uses older editions of both electrical safety standards. Both were published after the rulemaking began.

There will be a six-month public review period before the new OSHA Subpart S rule becomes effective on Aug. 13, 2007.             EC