Telephone conductors must be separated by ______ from light and power conductors unless in a raceway or specific types of cable.

Telephone conductors must be separated by 12 inches from light and power conductors to reduce the risk of electromagnetic interference that can affect the performance of the telephone system. This separation helps maintain the integrity of the signals carried by the telephone lines. When separated by this distance, it minimizes the potential for crosstalk and ensures that high-voltage power wiring does not induce noise into the lower-voltage telephone conductors.

While alternative distances may be applicable under certain conditions, the NEC (National Electrical Code) specifically mandates this 12-inch separation in general installations when telephone conductors are not contained within raceways or specific types of cable designed to reduce interference. In situations where conductors run parallel to each other without such protective measures, the 12-inch guideline serves as a standard safeguard to ensure reliable communication.