Ungrounded AC systems operating between 120 volts and what voltage must have ground detectors installed?

Ground detectors are necessary for ungrounded AC systems to ensure safety and system integrity. In the context of ungrounded AC systems operating at a voltage of 120 volts up to high voltage levels, it is crucial to monitor for any ground faults that may occur. Ground detection helps in identifying insulation failures, thus preventing potential electrical hazards such as shock or fire.

In many electrical codes and standards, including those outlined in the National Electrical Code (NEC), ungrounded systems above certain voltage levels require ground detectors to protect equipment and personnel.

For ungrounded systems operating between 120 volts and up to 1,000 volts, the requirement for ground detectors applies. This includes 240 volts and 480 volts, as they fall within the specified voltage range. Thus, the inclusion of all mentioned voltage levels is necessary, making it clear that ground detectors should be installed in any ungrounded AC system within this range to enhance safety measures effectively.