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Digital Circuit Boards: Mach 1 GHz by Ralph Morrison

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5.13 Grounding in Facilities: a Brief Review

N.B.
A grounding rod eliminates interference the way a flag pole eliminates sunlight.

The term grounding has many meanings. In utility power, the term means a connection to earth or its equivalent. In an aircraft or an automobile, the metal framework is the equivalent of earth. In a building, one of the power conductors at the service entrance must be earthed to provide a path for lightning. If lightning should hit the utility wiring, the intent is to provide an earth path for current flow outside of the facility. For uniformity, these grounding rules are followed even if the power is brought into a facility underground.

The grounding electrode system in a building includes such diverse items such as building steel, plumbing, gas lines, conduit, metal floor mats, boilers, motor frames, air ducts, and all equipment grounding conductors. In effect, all of the conductors in a building that could contact a power conductor must provide a fault path back to the service entrance ground. There can only be one grounding electrode system in a facility. The grounding electrode system can be multiply earthed. The grounding electrode system cannot be used as a path for power current.

Equipment grounding conductors (safety conductors, bare wires, or green wires) are used for fault protection and for shock avoidance inside a facility. Equipment grounding conductors are a part of the grounding electrode system. Equipment grounding conductors ...

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