why are secondaries bare?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "lews therin telamon by way of Terry Fritz <twftesla-at-uswest-dot-net>" <dreamer-at-mindsong-dot-net>


Hi list, first post for me, but I've been lurking for awhile.


This might be so fundamental of a question you guys will be bored, but 
I don't think I've ever seen an answer and I don't have anyone to
ask.  What is the electrical reason that the secondary windings are always
bare on TCs or on any transformer.  They're just responding to magnetic
fields from the primary, right?  Magnetic fields, unlike electricity, know
no insulation, so why leave the secondary uncovered.  It could still be
stripped at the end and grounded and connected to a toroid...

Excuse my ignorance if I'm grossly misinformed about something.

--lews therin telamon.