What condition must be met for the transformer secondary side voltage to necessitate grounding?

For a transformer secondary side voltage to necessitate grounding, it is crucial to understand the safety standards that dictate grounding practices. The correct choice indicates that the average voltage must exceed 75 V to warrant grounding. This threshold is significant because voltages above this level can pose safety hazards, including the risk of electric shock to personnel and exposure to equipment damage. Grounding is a protective measure that helps to mitigate these risks by providing a low-resistance path for fault currents, ensuring both safety and equipment reliability.

Establishing this threshold is consistent with various electrical codes and standards, which emphasize that voltages above a specific value require grounding to enhance safety and prevent electrical hazards. Keeping the secondary voltage averaged over 75 V aligns with practices aimed at protecting individuals and ensuring compliance with safety regulations.