I agree with you that certain things don't get covered by the NEC. We just have to look at article 90 for that list.
Just for clarification, the word "stand-alone" refers to a power generation system that is not tied into the utility power grid. The NEC does apply to these kinds of installations whether it is a portable generator or a photovoltaic system. If you're talking about a prepackaged item that all you have to do is stick in the dirt after you take it out of the package then yes as was mentioned before, if it is UL listed then you would follow the directions for installation according to section 110.3(B). [I wonder does the UL inspect the manufacturer's installation instructions for the purpose of complying with the NEC and other codes?] However, with the solar lights I'm installing, I am pouring a 2 foot diameter concrete pier foundation and installing 20'x5" steel poles. Then the multi-part PV lighting system is being installed onto and within that pole. This kind of install (the pole at the very least) is considered a structure as defined by article 100. If this were a grid tied parking lot light it would be required to have a GES installed per section 250.32 unless, as the exeption states, it is supplied by only one branch circuit AND it also has an equipment grounding conductor run with the other circuit conductors. Also, in the case of the solar light and pole the applicable code section requires that equipment (not the system) be bonded together and grounded. I have yet to see anything in the code that exempts PV systems due to size or singularity in purpose.
As a side note pertaining to this job, I dug the foundtaion holes yesterday and today and installed the rebar. I decided to extend a section of rebar up into the pole cavity to use the foundation as a CEE as allowed in section 250.52(A)(3). No rods required. :thumbsup: