re: "I don't understand why the generator-alternator thing is such a touchy issue.
" -- me, neither, which is why I considered it indicative of something other than productive discussion and worthy of note in that regard. It was particularly noteworthy in the context of its two adjacent comments in the same vein.
re: "I guess I'm still not making myself clear.
" -- you are not alone! The topic is one of those that is simple yet complicated at the same time. That, with changes over time (learned via experience) in deciding how things should be done create a lot of confusion and misunderstanding.
re: "If any hot wire comes in contact with the frame or skin of the trailer and it is not grounded, the skin of the trailer would be at 120 volts.
" -- any voltage has to have a reference. That 120 volts only exists between the power leads. If one power lead is connected to the chassis ground, the 120v is only between that chassis ground and the other power lead. (the caveats involve induced voltages and split phase systems which can complicate the simple picture somewhat)
Unless you complete a circuit you will not get any current to flow and with no current, no shock.
In other words, in an isolated system a single wiring fault is not a shock hazard.
You can think of the neutral to chassis ground (and also to earth ground) bonding as a fault like this intentionally done to make one side of the power circuit at the same potential as the 'environment.' The reasons for this in modern, on grid, practice were thoroughly explored by the 'Standford Professor' and 'Grizzy' over on rv.net a while back. (interesting stuff).
What this gets into is the GFCI
and how it implemented in small, 120v, plug type gensets. Most of the discussion (like the link) assume NEC compliant grid attached wiring. For RV's and gensets, the context is a bit different (see separately derived systems - ( ECM1
but take care about the proper definition of neutral in the code to get the context, though)).
Note that the GFCI has essentially replaced the purpose of the polarity indicating light on Airstreams.
Again, my suggestion is to trust the manufacturer to be following code (he has significant financial and legal reasons to get it right) and make sure any modifications you make are also in accord with current code described practice for the circumstances of your application (RV, separately derived, on grid, etc). It is not generally a good thing to think you know more than codified experience or those who make a living at it.