The key difference is that a UL Listed product is complete and can be used as is by the purchaser. A UL recognized component is a component to be used in the construction of some other product.
以下链接相关解释相信能解决你的问题：
http://www.ul.com/global/eng/pages/corporate/aboutul/ulmarks/mark/ listed.gif The UL Listing Mark appears on end products and complete components suitable for factory and field installation. All of the products carrying a UL Listing Mark are covered by UL's Follow-Up Services program to verify that end products and components carrying the UL Listing Mark continue to be manufactured in compliance with UL's safety requirements.
recognized.gif Components covered by UL's Recognized Component program are intended to be installed in another device, system or end product. They are to be installed at the factory, not in the field and they may have restricted performance capabilities that limit their use. When a complete product or system containing UL Recognized Components is evaluated, the end-product evaluation process can be streamlined.
The UL component evaluation process may include a construction examination and testing. Guidelines addressing the suitability of a component when used in an end product are noted in UL's test report as conditions of acceptability. This information can also be found in UL's Online Certifications Directory and the UL iQTM parametric databases.
This information is from a printed newsletter dated 1997 and is presented here for archival purposes only. For current information, please see the main UL Mark pages at
http://www.ul.com/global/eng/pages/corporate/aboutul/ulmarks/mark/ A product is UL Listed if the UL Listing Mark is on the product, accompanied by the manufacturer's name, trade name, trademark or other authorized identification.
A UL Listing Mark on a product is always composed of four elements: the "UL in a circle Mark, the word "LISTED in capital letters, an alpha-numeric control number, and the product name, (e.g., "toaster and "portable lamp). Sometimes the UL file number is used as company identification. The UL Listing Mark on a product is the manufacturer's representation that samples of that complete product have been tested by UL to nationally recognized Safety Standards and found to be free from reasonably foreseeable risk of fire, electric shock and related hazards and that the product was manufactured under UL's Follow-Up Services program.
Let's assume, for example, you are looking at the installation of a spa in a health club. If you can locate a nameplate marking on the spa with the complete UL Listing Mark and the other information noted above, the spa, the "end-product, meets the requirements outlined in UL 1563, Electric Spas, Equipment Assemblies and Associated Equipment.
If you do not find a UL Listing Mark on the product, you may find, on closer examination, that some of the individual components in the spa "such as the pump, control, heater or filter" have the UL Recognized Component Mark. And some manufacturers may claim that because the components are UL Recognized, the product in which they're assembled meets all the necessary requirements. But that's not necessarily the case, because the UL Recognized Component Mark means that the component alone meets the requirements for a limited, specified use. Remember, the complete UL Listing Mark and related information on the product indicate the spa (or other end-product) is UL Listed.
UL's Component Recognition Service covers the testing and evaluation of component products that are incomplete or restricted in performance capabilities. These components will later be used in complete end-products or systems Listed by UL. UL's Component Recognition Service covers millions of components, such as plastics, wire and printed wiring boards, that may be used in either very specific, or a broad spectrum of end-products, or even components such as motors or power supplies. These components are not intended for separate installation in the field " they are intended for use as components of complete equipment submitted for investigation to UL.
Component/end-product compatibility is the critical link between certification of a component and certification of the end-product in which the component is used. Use of UL Recognized Components in a spa (or any other product) does not mean the spa itself is UL Listed.
