JosephKK said:
DO NOT confuse nor conflate breakdown ratings with operational ratings.
Breakdown ratings are typically 8 to 10 (or more) times higher than
operating ratings. This applies to most dielectrics whether used for
insulation or to build capacitors.
True dat. Also true that plain old silicone caulk (aka RTV for room
temperature vulcanizing) has impressive insulating abilities for a
common material, so it would not be surprising if a tape adhesive using
silicone rubber did as well. But confusing breakdown and operational
will lead to getting bitten. For one thing, geometry matters a lot, and
any actual test will have a specific geometry which may or may not look
like your application.
In ASCII art >| is much harder to insulate than )| or ||, for instance.
On a purely "quick test to destruction" (hipot - crank up voltage until
current flows) basis while working on some lab equipment, I got 30KV
from ordinary (well, probably 3M ordinary, but not the high-voltage
version, for sure) heat shrink tubing. Doesn't mean you should design
for that...nor did I measure what thickness it had shrunk to.
There may also be some sort of surface effect with the different unit
breakdown for different thicknesses of kapton. As such, two wraps of
thinner material may be better than one wrap of thicker material (and
that's even more true in the real world where defects and dirt may
happen.)
Generally, anything designed to the hairy edge of breakdown will
eventually blow up, short out, etc. As such, outside of a lab
environment where you need to push the hairy edge and have designed
things to fail gracefully (or at least without killing anyone) when they
do fail, it's best to avoid that.
