One of the most popular, though often misused ratings, is the NEMA 12 rating. NEMA 12 enclosures are sealed to protect against falling dirt, circulating dust, fibers and so on. It is a great choice in a factory where there are no concerns about liquids, as this rating does not protect against liquids spilled or sprayed on the product. It also is for indoor use only. Therefore, choosing this when a cleaning spray might be required, or oils might drip is a mistake.