Are ground detectors required for 480-volt, 3-phase, ungrounded, delta-connected systems?

Ground detectors are indeed required in 480-volt, 3-phase, ungrounded, delta-connected systems because these systems can present a significant safety risk if a fault occurs. In ungrounded systems, any unintentional grounding of a phase can create hazardous situations and can lead to equipment damage or safety issues.

The purpose of ground detectors in these systems is to provide a means of monitoring and detecting fault conditions. These devices will alert operators to the presence of a ground fault, enabling them to take necessary precautions or actions before the fault escalates. In the absence of a ground detector, there might be no indication of a fault until it causes a loss of system functionality or even a dangerous condition.

While there can be local regulations or certain conditions under which ground detectors might be enforced more stringently, the general requirement for their use in these types of systems is to enhance safety and risk management.