We are designing transformers for use in products that will require the CE Mark, and we need to use triple insulated wire such as the Furukawa TEX-E wire to get the internal creepage and clearance required in 950. At present, the transformers run hot enough that a class 130C system is required.
I have recently discovered that both the Rubadue and Furukawa wires do not have a Class 130C temperature rating, which is what our insulation systems to date have all been. Both wires have UL and CSA listings only for Class 105C. Does anyone have any experience (ie success) in getting UL to accept these wires in Class B systems or at Class B temperatures? I have a copy of one RIS listing that includes the Furukawa wire, so I know the wire is good enough and it is possible to get the listing. However the number of materials in that listing was very low, so I didn't see any of our specific materials there (such as 3M#56, phenolic bobbins, etc.). While the listing proves it is possible to get a less-than-130C material into an 130C system, it doesn't do us much practical good. What I am looking for is the easiest way to prove that the temperatures we are getting are acceptable. I am not sure what the approach is for CE self-declaration: must the system be evaluated by some agency, looking for detrimental interactions under long-term or accelerated aging conditions? Suppose all our materials were rated at least 130C - can we just take a "the system is as good as the weakest link in the chain" approach? Now given that we are using a material rated less than 130C, what are our options? I know what the answers are for CSA and UL approvals, but for self-declaration for the CE Mark I'm not so sure. The safety engineer in me says I should submit our system to UL for the RIS process. Does anyone else have any easier ideas? Does anyone know what the time and cost involved are? Your help would be greatly appreciated, Yours truly, Jim Eichner Statpower Technologies Corporation [email protected] The opinions expressed are those of my invisible friend
