When is a white insulated conductor used in a cable required to be re-identified for use in a 3-way switch loop?

A white insulated conductor used in a cable is required to be re-identified for use in a 3-way switch loop when it is being utilized as a hot conductor instead of its typical role as a grounded conductor. This is necessary to prevent confusion and ensure safety, as white conductors are generally understood to indicate a neutral or grounded conductor in electrical installations.

In a 3-way switch setup, if a white wire is used to carry current as a hot conductor, it must be appropriately marked—often with a color such as black or red—to indicate its new function. This practice follows the National Electrical Code (NEC) guidelines, which prioritize clear identification of conductors to enhance safety and reduce the risk of accidental connections that could lead to electrical hazards. Re-identifying the wire ensures that anyone working on the circuit in the future understands that this conductor is not serving its typical neutral role, thereby maintaining compliance with electrical safety standards.