Originally Posted by ferroequinologist
I do have a question though. I have a grounding rod from an old military generator that I kept because I tend to keep everything. It has a slide hammer already installed. Do you think it would be a practical idea to pound that baby in everytime I get to a new campsite and connect it well to the chassis and hence the 120vac ground? Seems like that might trip the breaker on a RPBG outlet if I happened to connect to one. What are you thoughts and why or why not would this be worth doing? Thanks!
While at first blush this seems like a good idea, in actuality it will only help ground out any low-current (high resistance) hot-skin leakages. That's because a ground rod driven 8-ft into the dirt could easily have 100-ohms resistance to earth and still be code compliant. So let's assume you have a dead short between a wire with the insulation pinched and making contact with a screw or conduit (as in your example). Since Ohm's law states that voltage divided by resistance equals current (E/R=I) then 120-volts on the frame of your bus will only send 1.2 amps of fault current through your local ground rod (120 volts /100 ohms = 1.2 amperes). Since 1.2 amps will not trip a 20-amp breaker, you'll be lulled into a false sense of security with your local ground rod.
However, a ground rod WILL short out low-current (high resistance) hot-skin currents that are caused by normal hot-to-chassis leakages in all appliances with a grounded power plug. The NEC and UL allow up to 3.5 mA (milliamps) of leakage current from small grounded appliances such as your microwave, computer, television, etc... So these low-current leakages, while generally not dangerous as a shock hazard, would be shunted to earth by your local ground rod, could easily turn into high-current leakages in a heartbeat, which your local ground rod with 100-ohms earth resistance could do nothing to stop, or warn you about. A high-current hot-skin is certainly lethal if you're standing on the wet ground and touch your bus's metal door frame or steps at the same time.
So in short, a local ground rod won't do anything to trip your circuit breaker if plugged into an RPBG outlet.