OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

January 13, 1992

Mr. Arthur J. Smith III
Waldemar S. Nelson and Company Incorporated
Engineers and Architects
1200 St. Charles Avenue
New Orleans, Louisiana 70130

Dear Mr. Smith:

This is further response to your letter of October 11, concerning electrical safety-related work practices applicable to employees operating, or working on or nearby, motor control centers in the workplace. The safety guidance you requested follows.

In general, electrical safety-related work practices are predicated on electrical systems, including conductors and equipment, which are in compliance with 29 CFR 1910 Subpart S - Electrical. With specific reference to 29 CFR 1910.303(b)(1) and 304(e)(1)(i) and (e)(2), electrical equipment (as defined in 29 CFR 1910.339) is required to be designed and installed to conduct current safely. For additional information see paragraphs 110-9 and 10 and Article 240 of the National Electrical Code (NEC). Only motor control centers "approved for the purpose", as defined in 29 CFR 1910.399, may be installed in the workplace.

Paragraph 5(a)(1) of the Occupational Safety and Health Act of 1970, requires the employer to provide a safe and healthful workplace for his or her employees. Thus, the employer is required to protect employees from recognized hazards, such as, the uncontrolled release of energy due to short circuit faults. For purpose of compliance with Occupational Safety and Health Administration standards, personal protective equipment, such as that required for compliance with 29 CFR 1910.335, is considered supplemental to engineering controls and administrative practices (such as those noted at the end of the third paragraph in your letter). According to 29 CFR 1910.334(c), only qualified persons may perform testing work, such as taking voltage and current readings and moving wires, on electrical circuits or equipment.

Please note that the standards on electrical protective devices at section 1910.337 of 29 CFR 1910 Subpart I - Personal Protective Equipment, are under consideration for revision. A notice of proposed rulemaking was published in the Federal Register, Volume 54, Number 19 of Tuesday, January 31, 1989. Adoption of American Society for Testing and Materials (ASTM) standards to replace references to American National Standards Institutes (ANSI) standards is a proposed change. The rationale for this change is explained in the preamble of page 4977. A copy of the proposed rulemaking and the notice of public hearing for this proposal are enclosed for your use (See issue 19 in the hearing notice). Currently, ASTM is developing a draft standard on protective clothing to be worn by electrical workers. An ASTM standard on this subject may be available in a year or two.

We appreciate your interest in employee safety and health. If we can be of further assistance, please do not hesitate to contact us.


Patricia K. Clark, Director
Directorate of Compliance Programs