Check out Article 640 in the NEC. It refers heavily to Articles 400 and 725, specifically 640.21(B) and 640.42(B). I not sure specifically whether yours is a temp or permanent install, but in my experience, there are usually product skews for each application and they will generally include the appropriate connection at the enclosure for its intended use. As was said, check with the local AHJ when in doubt and get it in writing.
With the possible exception of outdoor carnivals, fairs, circuses and concerts (and even there it only addresses power to the systems) I see no requirements for outdoor installations in Art 640.
The NEC is concerned with the protection of life and property therefore you won't see much in the way of LV (limited to the spread of indoor fire and smoke). Outdoor LV simply doesn't present a hazard to life and property.
Also, the NEC is not a design manual so don't expect to see it specify what connectors to use although common sense dictates that for LV you use something that cannot be connected to line voltage by mistake.
Lastly, the NEC is not a book that you can pick up and take sections out of context from the rest of the book. You have to understand the entire Code before you can make a judgement as to whether an article applies to your situation because each section and article often relies heavily on other articles as well as an understanding of the way the book is written. Article 400 for instance does not apply to LV unless an Article or section in Art 725 or Art 800 on points back to it.