A database available online from Underwriters Laboratories (UL) allows a user to confirm that the cable in their possession legitimately has been certified by UL.
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Users can search the database using a cable's UL file number, which the company explains is "an alphanumeric designation assigned to a company upon successful completion of a product evaluation or company certification."
Often the UL file number begins with the letter "E" followed by a series of numerals. If you put the UL file number from the cable jacket, box or reel into the UL database, it will find the name of the cable manufacturer and cable type. If the information in the database does not match the cable you have, you have reason to be concerned.