You might want a peek @ 680 Paul....
~CS~
I did look at 680 and a sauna really doesn't, at least to me, fit the definitions listed in the scope of the article 680.1 - Maybe I am wrong, but to me, a sauna is simply an appliance; or at least as best as I can tell from the definitions listed.
680.1 says the article applies to the installation of electrical wiring for, and equipment in or adjacent to, all swimming, wading, therapeutic, and decorative pools; fountains, hot tubs; spas; and hydromassage bathtubs,.... All these have water involved.
You still say 680?... I'm curious. (Not trying to be a wise guy at all, I'm just looking at what I see.)