The primary purpose of grounding metal equipment to the grounding electrode system is to ___.

The primary purpose of grounding metal equipment to the grounding electrode system is to ensure safety and reliability in electrical installations. When metal parts are grounded, it helps keep these parts at the same voltage as the earth, which prevents any dangerous voltage buildup that could occur, especially in fault conditions. This is crucial for protecting individuals from electric shock when they come into contact with equipment.

Furthermore, grounding also serves to limit voltage surges that could result from lightning strikes or other transient events. By providing a direct path for excess voltage to dissipate into the ground, grounding helps to protect both equipment and personnel from damage and potential hazards caused by unexpected electrical surges.

Thus, the combination of maintaining a uniform voltage across metal parts and limiting voltage surges forms a comprehensive safety mechanism, making it clear why the correct answer incorporates both of these critical aspects of grounding.