In the vault test scenario, what was the potential voltage drop experienced by the worker when in contact with an ungrounded case?

The scenario in question involves understanding the potential voltage drop that a worker might experience while in contact with an ungrounded case. In many electrical safety contexts, particularly in substations, it is crucial to assess the risk associated with ungrounded cases due to the potential for hazardous voltages.

The correct choice, which indicates a voltage drop of 748 V, aligns with established safety guidelines and standards. This voltage level is significant, as it can occur in situations where a person inadvertently creates a path to ground while interacting with ungrounded equipment. Therefore, the 748 V represents a serious safety concern and exemplifies the risks faced in electrical environments.

When assessing the other choices, it’s important to recognize that voltages lower than 748 V might not accurately reflect the real risks present in such ungrounded scenarios. Understanding these voltage levels helps in emphasizing the importance of proper grounding and safety protocols to prevent electrical accidents in the workplace.