UL (Underwriters Laboratories Inc.)
UL is an independent product safety certification organization founded by an American underwriters’ association to develop standards and test procedures for product safety. Although obtaining UL certification is voluntary, most of electrical products are certified by UL in North America. To obtain the UL certification for an electrical product, main components to be built into the product should be UL-certified. There are 2 types of UL marks: a UL Listing mark and a UL Recognized Component mark for a component that UL finds it acceptable for use in a complete UL Listed product.
CSA (Canadian Standards Association)
CSA is a nonprofit, nongovernmental standard-setting organization. Selling products which are not CSA-certified is banned in Canada. In accordance with Mutual Recognition Agreement concluded between UL and CSA, a UL Listing mark and UL Recognized Component mark are used also by CSA.