What marking is required for ungrounded systems at their first disconnecting means?

The correct marking required for ungrounded systems at their first disconnecting means is “Caution: Ungrounded System Operating - Volts Between Conductors.” This marking serves a critical safety purpose by clearly indicating the nature of the electrical system to anyone who may come in contact with it. The warning is essential for maintaining safety as ungrounded systems present unique hazards; specifically, they can still pose a shock risk due to the potential differences that can occur between conductors.

By providing a clear warning, individuals are informed that they must exercise extra caution when working near or with the system, ensuring that proper safety protocols are followed. The specific wording highlights that, despite the absence of a direct ground, dangerous voltage levels can be present, helping to prevent accidents and injuries.

The requirement for this specific marking aligns with safety standards and regulations designed to protect personnel working with or near electrical systems, making it a vital aspect of grounding and bonding practices.