In USA nowadays, the wiring, earthing, bonding and rods are well specified in the regulatory, NEC, NFPA, etc.
I am sure other locales EU, AU, UK have smilar.
I have not encountered anything but thick copper rods, clamps, wiring.
Earthing is usueally a number of 0.375" = 8mm 10' long copper rods spaced out in moist earth.
Resistance to the earth is specified and measured.
Bon Chance
Jon