In a cable or raceway, what is required for all conductors with respect to voltage rating?

• A. All conductors must be insulated for the maximum voltage of any conductor in the same enclosure.
• B. Only the hot conductors must be insulated to the maximum voltage.
• C. Conductor insulation can be shared between conductors of different voltages.
• D. Insulation is not required if conductors are low voltage.

Answer: (A)

All conductors inside the same cable or raceway must have insulation rated for the highest voltage present in that enclosure. This ensures the insulation can withstand the electric stress from any conductor and prevents arcing or breakdown between conductors at different voltages. Insulation for one conductor isn’t enough to protect neighboring conductors if a higher-voltage circuit is present, and there’s no exception that lowers insulation requirements for low-voltage wiring. So, every conductor must be insulated to the maximum voltage found among them.