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.

February 18, 1980

                  Regional Administrator


THRU:             ROGER CLARK
                  Field Coordinator

FROM:             GROVER C. WRENN
                  Director Federal Compliance and State Programs

SUBJECT:          Citing of Reversed Polarity

In response to your inquiry on reversed polarity in requirement for correct polarity in receptacles is indicated by the 1971 National Electrical Code sections 200-2, 200-9, and 200-10(b). These sections require the grounded conductor to be properly identified. If the grounded conductor is connected to the wrong terminal in a receptacle, it is no longer correctly identified. Also, Sections 200-7 generally prohibits ungrounded conductors from being identified with a white or natural gray color. This requirement would be violated if the ungrounded conductor were connected to the identified terminal. In the 1978 NEC and in the Office of Standards Development proposed revision of Subpart S, there is a new requirement covering reversed polarity specifically.

The hazards of reversed polarity are discussed in the two enclosures.