# UL listing for USB device with battery, detachable cord and transformer

I want to import a device (for resale) that comprises the following components:

• Wall transformer (already UL listed),
• USB wire,
• LED light assembly,

The question is this: do I need to get a system certification (from CSA or UL) for the entire device or can I use the existing UL mark for the component that plugs into the mains (the transformer)?

I am getting contradictory information. Some are saying that only the transformer needs the UL listing while others say that the entire system needs the mark (dramatically increasing the cost, especially considering the required quarterly audits etc).

In case this matters, the battery is NOT removable and carries its own mark.

• I am interest in this too, for my own products I am designing. I may have integrated battery and charger system, but the external charger I need to just source and re-sell into my package.. Sep 15 '14 at 11:59
• Transformers already listed as "Class 2" reduce the evaluations a long way. Batteries that are Listed also make things simpler, But is it listed or Recognized? The symbol is "RU"( with the R reversed)? they can have hidden conditions of acceptability that may mean tests have to be performed ... Sep 15 '14 at 12:19
• To get a system certified by UL costs $15k to which one needs to add$4k pore year for mandatory quarterly audits. Going with the pre-existing UL for the charger/transformer allows one to use an existing audit loop at minimal charge (you are sharing with many other companies). Since UL was originally developed by insurance companies (for AC applications), I can see USB devices being "exempt" but I am not sure, hence the question. I would rather not follow up with UL directly yet, they simply say that it is mandatory, regardless of details - I just went through that with another product. Sep 18 '14 at 2:15
• @Sparetech: Downvoted because your question has to do with regulatory issues, not design. Dec 14 '14 at 15:18
• You can ask UL or CSA. It will be a similar experience to asking a barber if they think you need a haircut. What do your major customers require? May 19 '15 at 17:00

The simplest solution is to ask UL or CSA for a quote ... you don't have accept the quote.

• This doesn't address the question at all. The OP is asking if it needs to be certified, not how much it costs. This is something i happen to be very interested in myself Jan 2 '15 at 3:34
• I have re-read the question and you are correct. Strictly speaking it may not need evalution to the letter of the law (depending on the state? or local regulations) but any fires etc caused by the device may not be covered under insurance if it was not _ evaluated_... which for someone buying it might be important (company policy, house insurance) Jan 2 '15 at 12:03
• I am not personally aware of any state or municipality that requires UL listing. I am not an expert in the subject, but I have worked on projects that both were and were not UL listed. I do, however, know of some stores that will only stock UL listed goods. Jan 26 '15 at 22:58
• In this case the end user's organization might require only "evaluated" products on the premises..either by choice or insurance requirements etc...No law requires UL. what they often require is "evaluated" products ...which could be any of a variety of evaluation organisations...it just UL is the most well known in the US.. Jan 27 '15 at 0:54
• The local electrical codes ,for example (NEC - National Electrical Codes in the US) ,requires Listed / evaluated parts.. then the state adopts the code as part of it's building safety laws... effectively law I believe. The choice to use UL is then down to the state in this case. Aug 3 '15 at 7:39

If you want UL certification for your product, what you'll need to do is find out which UL standard best applies to your product as a whole, and which other standards it references. Then, you'll have to read the applicable standards and find out what requirements your product has to meet and what tests it has to pass, in order to qualify for the UL mark. Then your product will have to be tested by an approved testing facility.

If you use some components that are UL recognized components, they will probably already be in compliance with the UL standard for your end product. But just using some UL recognized components, such as a wall transformer power supply, will not allow you to use that UL mark on your product.

A good place to begin the process is UL.com, where you can search for info on standards and purchase the standards. Also, you can contact some Nationally Recognized Testing Labs (NRTLs) for price quotes on testing to meet the applicable standard(s). It can be a long and involved process, in which you pre-test your product to find out if it will pass the UL tests, make corrections as needed and then submit it for formal testing.