In fact, they are the Jen-Ter foil laminated elements. We've been using these for years but have since added an embedded PEPI to the design. I will reach out to my contact a jen-ter to aid with this issue. My project is currently on hold a UL...
I'm currently conducting IEC 60335-1 testing on a commercial appliance that utilized foil heating elements.
IEC requires that we conduct a leakage current test after humidity conditioning. I have noticed that the foil elements are absorbing enough of the moisture to cause the appliance to fail...