High Resistance Grounding Comparison Chart – Standard Practices For Industrial Plants

600 volts and lower
2.4 to 35 kv

Grounding Method
Solid Grounding & High-Resistance
Low Resistance Grounding

NOTE: A recent trend on 600-volt and lower systems has been to use high resistance grounding with all the inherent advantages it has to offer.
Comparative Benchmarks for Various Grounding Methods
Methods of Grounding
Characteristics Ungrounded Solid Grounded Low Resistance High Resistance
Immunity to transient over-voltages Worst Good Good Best
Increase in voltage stress under line-to-ground fault conditions Poor Best Good Poor
Equipment protected against arc fault damage Worst Poor Better Best
Safety to personal Worst Better Good Best
Service reliability Worst Good Better Best
Maintenance cost Worst Good Better Best
Continued production after first ground fault Better Poor Poor Best
Ease of locating first ground fault Worst Good Better Best
Permits designer to coordinate protective devises Not Possible Good Better Best
Ground fault protection can be added easily Worst Good Better Best
Two voltage levels on the same system Not Possible Best Not Possible Not Possible
Reduction in frequency of faults Worst Better Good Best
First high ground fault current flows over grounding circuit Best Worst Good Better
Potential flashover to ground Poor Worst Good Best


Additional Information & Documents

High Resistance Grounding