81.2-1991 IEEE Guide for Measurement of Impedance and Safety Characteristics of Large Extended or Interconnected Grounding Systems
The purpose of this guide is to present practical instrumentation methods that may be used for the measurement of impedance to remote earth, step and touch potentials, and current distributions of large extended or interconnected grounding systems ranging in complexity from small grids (less than 900 m/sup 2/), with only a few connected overhead or direct burial bare concentric neutrals, to large grids (greater than 20 000 m/sup 2/), with many connected neutrals, overhead ground wires (sky wires), counterpoises, grid tie conductors, cable shields, and metallic pipes.
