When a grounded conductor is installed, what rule applies to its size in relation to ungrounded conductors?

The requirement that the grounded conductor must not be smaller than the specified minimum size is rooted in safety and performance standards related to grounding and bonding practices. This guideline ensures that the grounded conductor can effectively handle fault currents that may arise during a short circuit or other electrical disturbances without becoming a safety hazard.

If a grounded conductor were smaller than the minimum size specified in electrical codes, it might not be capable of carrying the necessary fault current to ground reliably. This failure could result in overheating, potential equipment damage, or even fire hazards. Therefore, by ensuring the grounded conductor meets at least the minimum size requirements, it can provide an effective path for fault currents and contribute to the overall safety and integrity of the electrical system.

In this context, the other options do not align with the established electrical codes and practices that prioritize safety, reliability, and performance. The grounded conductor's size being larger than ungrounded conductors or matching the load exactly does not guarantee that it will function effectively under fault conditions, while being the same size as ungrounded conductors does not address the specific safety requirements necessary for proper grounding.