At what voltage level (VAC) phase to phase must approved protective devices be used?

The use of approved protective devices is critical for ensuring safety and compliance in electrical systems, particularly in high-voltage applications. In this context, the voltage level at which these protective devices must be employed is specifically set at 15,000 VAC phase to phase. Implementing protective devices at this voltage level helps prevent accidents and equipment damage that could result from overcurrents, short circuits, and other electrical faults.

Using protective devices effectively at 15,000 VAC ensures that systems remain operational while minimizing risks such as electrical shock, fire hazards, and equipment failure. Adhering to this standard reflects best practices in the industry and aligns with regulatory requirements for maintaining safety in high-voltage installations. Thus, the answer emphasizes the importance of using protective devices at this voltage threshold.