As Don (resqcapt19) has astutely pointed out in posts at E-C.net, a very [perhaps the most] critical part of “grounding” is bonding to limit potential difference between equipment enclosures/components. This is only achieved through low-impedance interconnections, where relying on ground electrodes to establish any sort of return path for <600V systems is nothing short of treacherous. Applied to portable equipment, driven rods can give a false sense of security that local electrical things are “safe,” sometimes to the point of little concern for properly installed, low-impedance bonding routed with circuit conductors.
