As long as the illuminator is 5' from the pool I think 300.5 applies so the UF could be 12". If it is cord and plug you must still make a case that this is 10'+ since 680.22(A)(1) specifically says "directly related to the circulation and sanitation system" when it talks about the way you can have a receptacle between 5 and 10 feet. All others shall be 10' or farther 680.22(A)(2) ulless you can really make the restricted space test in (4).
