Electrical

MEXICOWANDERER wrote:
If a generator is 240 vac it has a viable neutral L0

If a generator is a 2-wire 120vac, it can not have a neutral. It would have to center tap the 120 vac sine wave to obtain a 60vac signal. It like all other 2-wire generators does not have an absurd center tap.

So a plug-in receptacle tester used here, is worthless to determine "polarity".

A single phase generator built into an RV has one of the sides of the 120V output bonded to the chassis ground, and so that side becomes the neutral in some sense. It is of course true that the entire system is floating (assuming one doesn't attach the chassis to a ground rod or something) and likewise that this is not a split-phase system with a well-defined neutral inherent to the output.

Showing a reversed polarity on generator means that the wrong connection from the generator is bonded to the chassis, or alternately that the output wires were transposed on their way to the transfer switch. It's a problem that should be corrected, and indeed can be fixed pretty easily.

Incidentally, there are some relatively rare situations where 60V split phase wiring is used. One such use is "technical power" systems for audio equipment in studios, scientific instruments in labs, and other areas where it's important to minimize induced noise; having the power supply balanced with respect to ground helps with that. Another place it's used is in construction site power in the UK, where legally the maximum voltage in the system cannot exceed 55V RMS with respect to ground in an effort to reduce shock and electrocution danger. Neither of these has any bearing on RV generator installations, of course.