On 29/8/96 Peter Tarver wrote: >On the other side of the coin, Annex U only allows winding wire that is = >spirally wrapped in polyimide film, which the subject wire is not. = >Properly used, I'm confident that TEX-E will make it through most any UL = >evaluation, particulalry for ITE, since that was my goal in doing the = >work. The same probably applies to CSA (Egon?). However, you will = >probably have more difficulty with the application elsewhere than in the = >northern bits of North America.
There are several manufacturers of such extruded triple-insulated wire, many of which, including Furukawa Electric, have received CSA certification and UL recognition. Of course I can not recommend or endorse any particular manufacturer, and I'm sure that they are all equally suitable for the application. But purely by coincidence, I've also had occasion to meet with Furukawa. Both CSA and UL have accepted this kind of wire for use in ITE products. Before the inception of Annex U, this was accepted based on the requirements of thin film insulation. Test were done to special productions of the subject wire that were made especially for CSA/UL, with only 2 layers of insulation (both inner and both outer ones). There were no test failures. Annex U has complicated things however, by specifying the specific materials that can be used; namely polyimide. The subject wire uses polyamide. Not being a chemical or materials engineer, I really don't know what the difference is, but needless to say, this is now no longer officially acceptable. Of course, since it was accepted before, I'm sure CSA and UL will continue to accept it for the time being. The same policy appears to apply to most European agencies, since they had also accepted this wire in the past. However, there is one European agency that is currently flatly refusing to accept this kind of wire. They are being strictly correct in rejecting this, since it doesn't comply with the wording in IEC950. This situation is not expected to change until the publication of Ammendment 4 By the way, it is my PRIVATE opinion that IEC950 should not specify specific materials at the exclusion of enything else. I'm certainly not a materials expert and neither are most agency product safety professionals, so I'd rather see a test that can be performed. If Annex U is suitable for certain types of wire, then it should apply to all types. >At the time I was performing the evaluation on the subject winding wire, = >the proposal for Annex U had been made, but was not yet voted on in TC74 = >or in some similar state of being. It was my understanding then that = >there was either one or a small core of magnet wire manufacturers in = >Europe (German, meguesses) that pushed for Annex U. I urged Furukawa to = >take the issue up with TC 74, but haven't heard or read anything on topic = >since. As it happens, I also urged them to lobby TC74. In fact we managed to get them a one hour presentation at the TC-74 meeting in Copenhagen last September, and again at the Paris meeting in April. To give credit where credit is due, UL was also instrumental in helping to secure these hearings (thanks Al and Lal!) We also helped them prepare the technical arguments, test data and presentation materials, which were received very well by the members of TC74. They gave an excellent presentation and, as a result, it is my understanding that the wording in IEC950 will change to allow for "polyimide ... OR EQUIVALENT in compliance with Annex U." This will show up in Ammendment 4. Well, I certainly hope it does, anyway. I have an Ammendment 4 DRAFT here that includes this ... If you have any opinions, ideas to share, help to offer, or whatever, the person in charge of this project at Furukawa is Mr. Shigeo Yamaguchi, based near Tokyo, Japan. His e-mail address is QWL01633 at NIFTY. Sorry, but I don't know the syntax for contacting Nifty via Internet. Using Compuserve, all I do is: NIFTY:QWL01633. I think I've seen it as: [email protected] but I'm not certain. By the way, Mr. Yamaguch is not aware that I'm sending this message, and I hope that I have not offended him in any way by sharing his address. Of course, I am sending him a cc: at this time. Again, I reiterate that I can not endorse any particular company. But I would like to mention that Furukawa appears to be the only company taking a proactive role in this project, and I think they deserve some credit for this. And again, opinions expressed above are purely personal and don't necessarily bear any resemblance to my employer's official policy. In fact, I'm probably in deep s... right now. Regards, Egon Varju
