Changing Concepts and Equipment Applied on Grounded Low-Voltage Systems

A great amount of information and opinion has been written about grounding versus ungrounding low-voltage systems, but no magic application formula has arisen. Each system design decision must be made on an individual system basis modified by planned plant operating procedures. Because of the number of circuit devices involved, economics, and the integrity of electrical apparatus, the decision on extent of application of ground detecting equipment is difficult. A single suggestion to cover all system ground protection questions is impossible. Without firm assurances from the operating management for continued availability of skilled and experienced maintenance personnel, the authors would favor the solidly grounded system utilizing sensitive protection devices for isolation of low-level¿and above¿ground faults.