Final answer:
A re-identified white conductor is not permitted to be used if it's part of a cable with more than three conductors, part of a multiwire branch circuit, or isn't in a flexible cord or used for a switch loop, according to the National Electrical Code (NEC). Using a white conductor for anything other than a neutral in these situations can result in safety hazards.
Step-by-step explanation:
A re-identified white conductor is not permitted to be used where required to be permanently re-identified. Specifically, according to the National Electrical Code (NEC), a white conductor that is part of a cable assembly where the white conductor is used for a purpose other than a neutral is allowed to be re-identified with tape, paint, or other effective means at its terminations and at each location where the conductor is visible and accessible. This re-identification is to signify its use as a hot or ungrounded conductor. Failure to comply with these NEC regulations not only it's a code violation but also can lead to severe safety hazards, as the conductor may be incorrectly assumed to be a neutral when it is in fact energized.