Hi, Does anyone know of any references on how insulation in a small coil (EFD10 transformer) should be specified? We have a small coil design where we use #36 and #32 wire. The #36 wire I had on my shelf had insulation that failed at about 400V. I test by taping a short length of wire directly on copper clad board. I purchased some Quad Build that had a 4650V rating and it passes when I test to 6000V. Likewise a single layer of polyester transformer tape also withstands 6000V. The Question: With the above wire ratings and measurements what is the appropriate rating for the final core for 60 second maximum voltage? Assume 2 coils with a single layer of tape between them. Also: I have been impregnating the coils with a 4000V / mil thermosetting varnish using a small vacuum fixture. Thanks, Bob K. ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________