Why don't RVs need an earth ground for AC circuits

There should be a sticky for this question. A search will show lots of threads.

The short answer, shore power is referenced to ground. Portable generators or inverters have no reference to ground. They don't even have a neutral. They have two wires, either one could be defined as "Hot" or as "Neutral". You could bond the "neutral" to generator chassis/receptical ground. It won't make the MH any safer. In fact, the MH will become less safe. With no bond, it takes two faults to get shocked. It takes just one fault to get shocked when bonded.

My first thought is that it's a compromise. It would be ideal if an RV's frame and skin was always earth grounded. More developed campgrounds provide this via the shore connection. For less developed campgrounds they could provide ground connections at each site, with a lot of cost to install and maintain them. When moving down the road an earth ground is obviously impractical. So the code allows the vehicle frame to "act" as the earth ground. What about shock risk? Shore power always has one of its conductors earth grounded, so an accidentally hot frame or skin could give a full-blown shock. Earth grounding is therefore important when on shore power. The portable or vehicle mounted generator has all of its conductors isolated from earth ground, so there should be no current path for a shock to earth ground. There is sometimes a conduction path from the vehicle frame to ground, so the vehicle frame may or may not be connected to some degree to earth ground. If the generator isn't bonded, there's no current path to earth ground. If it is bonded, any current path from the frame to earth ground will put them at the same potential, meaning no current path for a shock.

This is NOT to answer your question, but it might interest you.

Navy combat ships do NOT ground any system. The reason
is that, with our 'normal' HOUSEHOLD grounded systems, if the HOT
wire touches ground the breaker trips or the fuse blows. In combat,
this is obviously NOT acceptable !............in place of the grounded
system, a GROUND DETECT system is used to detect grounds, and they
are removed as soon as possible.

I have long thought that this should be extended to homes and businesses.

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

When connected to shore power you have ground protection thru 'ground' lug and back thru power pedestal.

When connected to generator it acts like an isolation transformer. Since the power source is isolated, there's no way for part of the current to flow back to the source through the ground and there's no shock hazard from the voltage to ground.