Thx, I really just found here, a great explaination, as to why
Then why is it called an ?Equipment Grounding Conductor (EGC)? in the NEC if it?s primary purpose is to ?bond? things together? Simple answer: tradition. It?s always been called that, and the terms in the NEC have served to confuse people for a long time. Proposals have been made to change the term, and progress has been made, but the EGC continues to hold it?s misnomer.
Electricity does not seek the path of least resistance to the earth. It seeks all available paths back to it?s source, in proportion to their resistance. The reason that a person gets shocked when touching an ungrounded conductor and the earth is because the neutral of the system is repeatedly connected to earth in a grounded electrical system. The earth becomes part of a return path to the transformer ? it?s part of one route back to the source; the earth is not the destination for the electricity.
Driving a ground rod to ?ground? any electrical equipment does not provide the low-resistance path required to trip breakers. Driving a ground rod, or using a Ufer, or a metal water pipe is not a substitute for an EGC. A ground rod with 25 ohms to earth will allow almost five amps to escape the system into the earth when directly energized from a 120V source. Five amps will never trip a 15A or 20A breaker, and in the meantime everything bonded to this ground rod will be energized to 120V.