Question

to get the effective earthing through exposed and extraneous conductive paths the resistance of the earth grid system has to be at ?
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Answer 1

Answer:

Component parts of earthing system are to include the following: Earth electrode ... by buried earthing tape or cable, which is to have a total combined resistance ... Ring type earth electrode is to consist of earthing conductors, in a closed loop, ... Extraneous and exposed conductive parts of equipment are not to be used as ...

Exposed-Conductive-Part – Conductive part of equipment which can be touched and which is not normally live, but which may become live under fault conditions. Extraneous-Conductive-Part – A conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation

What is the normal value of earth resistance?

5.0 ohms

Ideally, a ground should be of zero ohms resistance. There is not one standard ground resistance threshold that is recognized by all agencies. However, the NFPA and IEEE have recommended a ground resistance value of 5.0 ohms or less.

Explanation: