The costs of PV systems have been dropping over recent years. They are increasingly affordable (and thus increasingly more popular). In over 300 Chinese cities, for example, solar cost is on par with grid cost.
One problem with any PV system is that it's a complicated, multi-trade installation. That means each trade must follow the appropriate codes or things can go sideways badly. In fact, a large corporation recently sued over the loss of several buildings due to fires attributed to problems with the PV systems.
Article 690 of the National Electrical Code (NEC) provides the electrical requirements for these installations. This is far from a “paint by numbers” situation. Just understanding the lingo is an undertaking; there are more than two dozen definitions in Sec. 690.2 along with half a dozen drawings. Adding to the complexity, these systems are often interactive with other power production sources and/or storage systems, such as batteries [Sec. 690.1]. All of this sets a high bar for being one of the “qualified persons” permitted to install these systems [Sec. 690.4(C)].
Aside from the massive glossary, Part I presents little in the way of general requirements.
