What Is The Difference Between UL Listed Products And UL Recoganized Products.

What is the difference between UL listed products and UL recoganized products.

Mercury Security systems access control solution , controllers are UL recoganized and reader modules are UL listed.


Hi A,

there is a good description here of the different terminology used by UL: http://ul.com/corporate/faq/general/terminology/

Reading carefully, the difference seems to be that "products" are UL-listed and "components" (those parts that make up a "product") are UL-recognized.

With this definition, i'm not sure how a controller qualifies as a UL-Recognized "component" that is part of a "product"?

In the strictest terms, UL Recognized Components are designed to be put within an assembly of some type (control panel, gate operator, etc.) which would then itself be capable of becoming UL Listed.

For example, in the case of a gate operator, a manufacturer might use UL Recognized relays and motors within the operator. He would then take the operator itself to get tested to obtain a UL Listing for the overall operator. It is my understanding that using UL Recognized Components speeds up the testing and approval process for the UL Listing.

If an AHJ requires a listing from a "recognized testing laboratory" (usually a code word for UL, but there are other labs), then just having a UL Recognized Component label may not cut it.

I'm not sure how this applies to access controller boards. Perhaps the intent is that the board would be placed in an enclosure (with or without a power supply) and that the completed assembly would then be submitted to obtain a UL Listing? Not sure.

We've gone through the whole UL Listing process recently (a VERY expensive and complex process) and they indeed test with power supplies and with enclosures-- these are an integral part of the UL listing process (they do attack-resistance tests on the enclosures). Our UL-Listed controllers MUST be shipped with the same model of enclosures with which they were tested (the model number of the enclosures and power supplies is part of the text of the UL-Listing on the UL website)

I'm very surprised that Mercury (or any other access manufacturer that sells into the US) would not be UL-Listed. This is an industry standard requirement in the access control business and many bids I have seen require that the products must be UL-Listed.