Earthing

Everybody would definitely prefer 0.0 Ohm resistance as well. However, discussing earth resistance (a.k.a. combined resistance of earthing system to the general mass of earth) involves answering the question: what is the purpose of making this resistance as low as practically possible? Or, better yet, what conditions the earthing arrangement needs to satisfy?

Does 1.0 Ohm resistance makes sense, if a $0.5MM facility is installed on solid limestone and achieving 1.0 Ohm resistance ...

Without a ground connection there is potential (excuse the pun) of leakage or wiring fault (or rarely a component fault) biasing the circuit voltage; this is bad because DC control wiring is nominally SELV (safe extra low voltage) and many safety provisions and even component ratings depend on this. I once encountered a problem with unbonded ring wiring (UK) where one phase of 230 AC power was biased to 640 V above ground (exceeded the insulation rating of some equipment). BTW, SELV also has ...

Sometimes adding more ground rods and pipes will not do achieve anything to bring the ground resistance down in high resistivity areas. Especially sometimes, adding more ground rods will not do anything to bring the resistance down (the resistance stays the same).

A good understanding of soil resistivity and related testing is extremely important. Some guidelines should be established for the soil testing. Similarly the testing and spacing to determine the soil resistivity with de ...