Having worked for UL as an engineer I have a few comments. UL does not "approve" anything- they List, Recognize and Classify items. "Approval" implies that an item can be used without regards to its limited testing by UL. The UL lawyers hate the term "Approved By UL" and routinely send out letters to the corporate abusers of that terminology. In the case of power supplies they are usually "Recognized" components meaning that they are tested to certain parameters but are dependent on the actual environment they are applied to (that is the backwards UL symbol). For instance, if a previously UL "Recognized" power supply is installed in a computer that is submitted for "Listing" and it is used within its UL defined "Recognition" than limited investigation is required. Also note that in the case of power supplies it's not important to UL whether they really work or not- only that they perform to the UL requirements which don't typically specify performance values. Jim
On Wednesday, September 30, 2015 at 9:14:11 PM UTC-7, gregebert wrote: > I did some research on UL/CSA approved transformers, and there is a > requirement that all windings withstand a minimum breakdown voltage, even > if they are intended to be connected together, such as dual-primaries. > Depending upon the VA rating and the voltage, the breakdown must be between > 1050 and 4000 V RMS according to how I read the spec (UL5058-2 / CSA C22.2 > #66). The test is conducted between 1 winding, and all other windings and > the core combined and at elevated temperature. There are copies of the spec > online. > > I knew there had to be some amount of isolation, but I did not realize it > was *that* high. While I would never expose or touch anything that is > supposedly "isolated", it does reassure me there is decent insulation. > > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/6979989c-4bef-492a-8912-86b0818600f0%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
