it Real Simple
the utility power is connected to earth ground
therefore circuits connected to utility power need an earth ground as a safety
if something shorts in an appliance or device, and earth ground completes the circuit and trios the breaker, rather than the device/appliance/tool being electrically HOT and you being the ground to complete the circuit
the RV genset or portable genset, is NOT connected to earth ground, if something shorts in the RV there is NO electrical circuit between RV and earth or portable tool/appliance and earth so power cannot flow between RV or tool and you to the ground and back to the generator
but it can with utility power
RV genset or portable genset is "isolated power"
if you want to drive a 10ft ground rod and ground your generator
go ahead and do so, but you are safer with out it
