You may have run across parts which are shown as ‘UL Listed’ and parts which are shown as ‘UL Recognized’. These two are not the same thing, and knowing the difference can help you get your design approved for production much more quickly.
“UL Listed” indicates that the product in question meets industry and safety standards and has passed the UL’s full battery of tests. Products that are certified to safety-related standards have been evaluated with regard to all reasonably foreseeable safety-related hazards, including fire, electrical shock and mechanical hazards. Such products are termed “UL Listed” . It is common to see UL Listed approvals on products that are installed into harsh environments. Because “UL Listed” status has more restrictions and is harder to achieve than “UL Recognized” status, many products not expected to be used in harsh environments are not subjected to this expensive testing.
“UL Recognized” usually applies to components that meets applicable industry standards. In some situations, specific types of components may be incomplete in construction or restricted in performance capabilities. These components are “Recognized” and may be suitable for factory installation on other equipment, where the limitations of use are known to the manufacturer and where their use within such limitations may be investigated by UL. Using UL Recognized components makes it easier for a product to achieve and maintain UL Recognized approval
In short, “UL Listed” tends to be for complete devices which are ready to be purchased and installed wherever they need to be, and is more difficult and expensive to obtain than “UL Recognized.” “UL Recognized” is more for specific subcomponents used to create a product or device, is easier and less expensive to obtain than ‘Listed’, and using these parts makes it easier for your end product to attain UL Listing.