Under what conditions may equipment grounding conductors be run in parallel?

• A. Never
• B. Only in dry environments
• C. Under certain conditions
• D. Whenever the installer desires

Answer: (C)

Equipment grounding conductors can be run in parallel only when specific rules are followed to keep the grounding path reliable and the overcurrent protection effective. This is not a blanket allowance, but a permission that applies to certain situations, typically for circuits with large fault currents where a single conductor would be impractical or insufficient.

The allowed conditions include: the parallel conductors must be the same size and material, run together in the same raceway, cable, or enclosure, and be connected to the same equipment grounding terminals so they form a single, common grounding path. They must be sized to carry the fault current for the largest overcurrent device in the circuit, ensuring the fault current can be cleared quickly. If these requirements aren’t met—different sizes or materials, different routes, or not terminating at the same point—the parallel arrangement could create unequal impedance and compromise protection.

So the correct choice reflects that parallel EGCs are permissible only under certain conditions, not universally or arbitrarily.