Who's Who In Power Supplies, 2013: Brands Vs. Manufacturers

How Do You Recognize The Manufacturer?

UL Numbers From Underwriters Laboratories

"Underwriters Laboratories, an independent firm working with product safety certification, has been active in the field of product testing and preparation of safety standards for more than a century. UL evaluates more than 19 000 types of products, components, materials and systems annually. Every year more than 20 billion UL marks are placed on products from 66 000 different manufacturers. The UL Group and its network of service providers include 68 testing and certification labs worldwide, serving customers in 102 countries."--From the About UL page at ul.com

Essentially, this means that all PSUs sold on the North American market must be marked with a UL number. This number should identify the actual manufacturer of a product. However, not every PSU has such a number. UL number omission on a North American product might indicate poor quality.

Step 1: Reading the UL Number

To find the UL number, there's no need to open your PSU or de-solder anything. Simply open your PC and look at the power supply's label. The UL number usually begins with an "E" followed by a string of numbers. See the three examples below.

If your PSU has such a number, you can move onto the next step, finding out what it means.

Online UL Number Query

Now let's find out more about your PSU. Go to the UL Online Certifications Directory and enter the UL number in the UL File Number field. If the number exists in the database, you should immediately see the result. If not, the number is invalid, fake, or the manufacturer no longer exists.

Link: Online Certifications Directory

  • rolli59
    Great article!
  • Darkerson
    I really wish I would have had something like this years ago, but either way this was a great treasure trove of useful info. Thanks!
  • _Pez_
    Now i'm afraid of every PSU out there... :X .. awesome work now I'll be more careful when selecting a PSU I will check everything in that moment like some sort of paranoia. ja ja LOL !
  • chefboyeb
    I have a Rosewill 950-DB and it's been working excellently for over a year now... How safe am I?
  • Tamz_msc
    Channel well is pretty good.You have great PSUs from them for both Antec and Corsair.
  • shades_aus
    That explains why my ANTEC power supplies have died. Although some were made by Seasonic, they were NOT designed by Seasonic.
  • PreferLinux
    As you were told with the last one, chokes do not mean passive PFC. They will be present in the filters (all of them, including input) of any PSU.
  • The Greater Good
    Ummm, Seasonic does make their own PSUs.
  • avatar_raq
    "For those companies that don't manufacture their own products, such as HEC and Seasonic"

    Huh? Since when Seasonic is not the maker of their products?
    Nice article and much needed. Thanks
  • PreferLinux
    shades_ausThat explains why my ANTEC power supplies have died. Although some were made by Seasonic, they were NOT designed by Seasonic.The ones in question were probably older ones with cheap caps that failed. And probably made by one of the lesser companies there too.