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.

June 24, 1992

Mr. Nicholas N. Price
Schnader, Harrison, Segal and Lewis
Attorney At Law
Suite 600
1600 Market Street
Philadelphia, Pennsylvania 19103

Dear Mr. Price:

This is in response to your March 26 letter, requesting an interpretation on the applicability of 29 CFR 1910 Subpart S, Electrical Standards to computer security devices manufactured by Quality Telecommunications Inc. (QTI).

In your letter you describe the QTI device, which consists of more than one component, as designed to be installed physically between the telephone company's termination point and the computer and its modem. Further, you identify one of the components, that is, the component with the greatest electrical hazard potential in the QTI device, as manufactured by another company and as "certified" by Underwriter's Laboratory, a nationally recognized testing laboratory (NRTL). Also, you indicate that the only time an employee or other individual would be in physical contact with the QTI's security device, which would be used rarely with personal computers, would be during installation, repairs or removal.

The primary concern of the Occupational Safety and Health Administration (OSHA) is that the QTI device not be able to create an electric shock, burn, or fire ignition hazard within itself, the computer, the modem system or associated interfaces. (Please note that an employee would be exposed to these hazards any time he or she is working in the vicinity of the equipment.) This concern is addressed by the "approval" requirement of 1910.303(a). This requirement (clarified by the definitions of "approved" and "acceptable" in 1910.399) applies to all equipment connected to or part of an electrical installation. Equipment must be determined to be safe by a nationally recognized testing laboratory as a complete unit. Listing of individual components by themselves is not recognized as approval of a system as a whole. Approval of a single component, even one having the greatest electrical hazard potential, does not remove OSHA's concern regarding the safety of the equipment operating as a complete unit.

For workplace servicing and maintenance of QTI devices, the electrical safety related work practices standards, that is, 1910.331 through 1910.335, apply. By 1910.333(c)(2), only qualified persons may work on electric circuit parts or equipment that have not been deenergized under the provisions of 1910.333(b).

Thank you for your interest in occupational safety and health. If we may be of further assistance, please contact us.


Patricia K. Clark, Director
Directorate of Compliance Programs