See Article 404, in particular 404.2. You are simply not allowed to switch the neutral. It doesn't matter if the load is polarity sensitive or not.
Also see 300.20 (A) requiring all conductors to be grouped together in metal enclosures and raceways.
Now I suppose that if this load was fed with 2 ungrounded conductors, and was in a non-metallic wiring method, then I think that it would be allowed...
