Roger- Look again. Articles you referenced only require that the products be "Listed" not UL Listed. There are possibilities, UL, ETL, Factory Mutual, CSA and MET to mention a few. There are no requirements that anything be UL Listed And another thing that bothers me is the fact that Article 500 quite often says that a product or piece of equipment shall be "Approved" and it makes no reference to a need for any Listing. Puts the onus on the Inspector to review a product for approval or acceptability without knowing how it will perform.
