I am saying that once the system is grounding the addition of grounding electrodes does not make any difference as far as the shock hazard. The impedance will be low enough without any additional grounding electrodes to conduct a fatal amount of current from a 120 volt source. Adding rods does not increase or decrease the hazard.
It is the electrode resistance that will make the difference. If the current path will carry a fatal amount of current it doesn't make any difference how much more current the path will carry.
But my point is that I don't think it makes any difference if you have one rod, two rods, 1000 rods, or a ufer or any other type of grounding electrode. It is my opinion that once the system is grounded at any point, the path back to the system via the earth would almost always have a low enough impedance to cause a fatal amount of current to flow.
First the grounding of a system has nothing to do with the available current. That is a function of the power source. There may be some rare cases where the path via to earth back to a grounded system would have such a high impedance that you would not get a fatal shock, but I would fully expect that the earth would not limit the current to a "safe" level in most cases.
I haven't made any studies, but have been able to have my wiggy show voltage with on probe on a 120 volt conductor and the second in the earth...nothing other than the wiggy probe itself. My wiggy requires about 15mA to pull in at 120 volts. Maybe not a fatal amount of current but a dangerous level. Remember that the 5mA trip for GFCIs was picked because about 95% of adult females can "let go" at that current. A higher percentage of adult males can let go at that current and a lower percent of children.
And as Mike pointed out, that is not the intended function of grounding.
The discussion we have been having has nothing to do with the purpose of connecting electrical systems to earth...it only has to do with the effects of that connection. It is also my opinion that the code use of the term "equipment grounding conductor" is a big part of the reason for the confusion about grounding and bonding.
We have to be careful with this. This is the very idea that leads people to think that a grounding electrode can take the place of the required equipment grounding conductor. Yes I know that is not the purpose as stated in the code rule that you cited, but my point is that connecting non-current carrying parts of electrical equipment that is supplied by a grounded system does very little to reduce the voltage from those non-current carrying parts as measured to earth, unless you are very close to the electrode.
The very reason for EGCs and main or system bonding jumpers. There will be a shock hazard at the faulted equipment until the OCPD clears the fault.
That is true, but under high fault current conditions, the voltage to earth at the faulted equipment can be dangerously high...until the fault is cleared.
The word "grounding" in EGC implies that the connection to earth is important for the EGC to do its job. I don't agree that the connection to earth plays any real part in the function of what the code calls an EGC. It bonds the non-current carrying parts back to the system grounded conductor to provide a low impedance fault clearing path. The fact that it is connected, indirectly, to earth is not important.
