If you have recently purchased an AC/DC adapter you might want to check out this public notice from the Underwriters Laboratories about some unauthorized UL markings:
Underwriters Laboratories (UL) is notifying consumers that the AC/DC Adapters, identified below, bear unauthorized UL Listing Marks for the United States and Canada. These products have not been evaluated by UL to the appropriate standards for safety for the United States and Canada, and are not authorized to bear the UL Mark. It is unknown if these products comply with United States or Canadian safety requirements.
Name of Product: AC/DC Adapter Models: GM601-120200; GM601-120300; GM601-240250; GM-240270.
Number of Units: Unknown
Date of Manufacture: Unknown
There are pictures of these units available on the UL website at UL warns of AC/DC adapters with unauthorized UL Marks.
Read entire UL Public Notices webpage – http://www.ul.com/global/eng/pages/corporate/newsroom/publicnotices/