It's not often that I get to use the same reply for two threads ... this one and the current one about working space
Let me start at the very beginning ...
The NEC is not, as we are clearly told in its' introduction, either a design manual or an instruction manual. As much as inspectors love to have things spelled out -in minute detail, they have the same duty as everyone else apply their judgement. Ours is a system of 'common law,' where we rely upon past practices as well as our neighbors to guide us in our interpretations of the law.
The locations of disconnects is one such area, where design judgement comes into play. For example, the disconnect for rooftop equipment may very well be best located - in terms of access by service personell - in a place that can only be accessed from a ladder. This would naturally place the disconnect above the 6-1/2 ft above grade that is referred to in various parts of the NEC.
Lest I belabor the obvious, it's also quite possible that 'good design' may call for more than just a single code-mandated disconnect.
We saw this issue present a different face recently, when an article in the IAEI magazine advocated the use of GFCI breakers, rather than devices. While that may make your monthly testing easier, it's of little comfort to the rooftop worker when one needs to be reset.
SOLAR, and other generation methods, have concerned me from the start, simply because the feeders are 'live' even when the switch at the panel is "off." It's more of a concern with solar, since multiple panels are often used together for a single feed - and there's no way to turn a solar panel 'off.' A fault in one unit can damage every other unit, unless there is some means to isolate each panel. Likewise, a short in a unit can make everything 'live,' for as long as the sun shines.
I would not, at this point, worry too much over stories of 'firemen getting shocked.' Not that I doubt the accounts; rather, I doubt the competence and completeness of the reporters. I also visit a 'self reliance' forum, and the creativity of the members who have 'gone solar' is exceeded only by their ignorance. I suspect that most of the problems will come from installations that have myriad code issues- the location of the disco being the least of them.
