High-resistance grounding has the advantage of no overcurrent-device with the first phase-to-ground fault—a.k.a. “process continuity”. But, if ignored the second phase-to-ground fault will cause operating of two overcurrent devices. Ground detection MUST be installed, monitored an acted upon rapidly at first-fault inception, or the whole idea is worthless.
Generally, ungrounded systems can be retrofitted with high-resistance grounding and simple ground detection at reasonable expense. One online paper is
www.neiengineering.com/papers/paper1JN.pdf [This message has been edited by Bjarney (edited 07-25-2004).]
