Grounding-more than a connection to earth

Grounding continues to be confusing to most engineers. The "rules" for grounding often are contradictory. The various rules were developed for specific electrical and communication systems. So long as these systems could be largely isolated from one another, both functionally and physically, the particular grounding rules could be relied upon. With the advent of the digital computer, the different electrically based systems have blended into complex arrays of cables and equipment. The grounding of these arrays must be approached electromagnetically rather than through the adherence to set rules, which may or may not be applicable.