Where a 250 kcmil copper GEC is subject to physical damage, it ___.

In the scenario where a 250 kcmil copper Grounding Electrode Conductor (GEC) is subjected to physical damage, utilizing Rigid Metal Conduit (RMC) is the appropriate choice. Running the GEC inside properly supported RMC provides an effective means of protection against physical damage. RMC offers a robust, rigid structure that shields the conductor from potential hazards such as impacts or abrasion, which could compromise its integrity.

Using RMC is a common practice in electrical installations where conductors need to be safeguarded. This conduit type also ensures that the GEC remains securely installed, minimizing risks associated with movement or environmental conditions that might otherwise expose the conductor to damage.

While exposing the conductor might seem plausible under certain circumstances, it does not provide the same level of protection as enclosing it within RMC. Since physical damage is a concern, employing a method that ensures maximum safeguarding, like RMC, is the most suitable option. Thus, the correct answer reflects the necessity for having robust protection for accidental impacts or environmental factors impacting the GEC.