Are metal boxes required to be grounded?

Metal boxes must be grounded to ensure safety and prevent electrical shock hazards. The grounding of metal boxes provides a path for fault currents, reducing the risk of electric shock and fire. In the event of a fault, grounding helps to ensure that the overcurrent protection devices like circuit breakers or fuses will operate properly, interrupting the flow of electricity quickly and minimizing potential injury or damage.

Grounding is particularly important in the case of metal boxes because they can conduct electricity if live wires or components come into contact with them. By grounding the boxes, any stray currents are directed safely to the ground instead of presenting a hazard to users or equipment. This requirement is consistent with the principles set forth in the National Electrical Code, ensuring that electrical installations maintain a high standard of safety.

While it's true that certain installations may have specific conditions under which grounding is emphasized, such as in outdoor applications or those connected to circuits, the general rule is that metal boxes must be grounded regardless of these factors to adhere to electrical safety standards.