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 http://www.osha.gov.

December 8, 1980

MEMORANDUM FOR:     GILBERT J. SAULTER
                    REGIONAL ADMINISTRATOR

ATTENTION:          HERBERT M. KURTZ

THRU:               JOHN MILES FIELD COORDINATOR

FROM:               BRUCE HILLENBRAND
                    ACTING DIRECTOR, FEDERAL COMPLIANCE
                    AND STATE PROGRAMS

SUBJECT:            Interpretation of 1910.309(a), NEC-1971
                    Articles 110-17(a)

This is in reference to your July 18, 1980, memorandum on the above subject. This also confirms conversations between Mr. Pete Wasko, a member of my staff, and Mr. Herbert Kurtz of your office and Mr. Thomas Curry, AD-Harlingen Area Office, on the subject matter. In response to your staff members' request in these conversations for written confirmation, this memorandum serves to substantiate our recommendation to withdrawal, as indefensible, the alleged violation of 29 CFR 1910.309(a), NEC Article 110-17(a), in the Harlingen Area Office's citation dated June 24, 1980, against Reynolds Aluminum Company.

The intent of NEC Article 110.17(a), which addresses the guarding of live parts, is to prevent workers from being able to contact both sides of an electric circuit. Contact with both the live (ungrounded) part and ground will provide a path for current to flow through the body. In normal workplace operations, contact with ground or a grounded object is very common and guarding against contact with live parts, as required by Article 110.17(a), is necessary. However, in the electrolytic cell line operation, contact with the live portion of electric circuits is required, and contact with ground or a grounded object is to be guarded against. The 1971 NEC is silent on the electrolytic cell line operation.

Therefore, applying 1910.309(a), NEC Article 110-17(a), to the electrolytic cell line operation or maintenance is inappropriate and legally indefensible. For further substantiation the 1978 NEC contains a new article 668 on electrolytic cells. The 1978 NEC Article 668-3(c)(Exceptions No. 1 and No. 4) specifically exempt Article 110 from applying in the electrolytic cell line working zone (see Articles 668-2 and 668-10 for definition of the electrolytic cell working zone).