Message-ID: <001301bf1b90$cd62ad60$c36b1b3f@oemcomputer>
Reply-To: "dfs" <dfs@gateway.net>
From: "dfs" <dfs@gateway.net>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: Wire insulation
Date: Wed, 20 Oct 1999 23:51:40 -0700
Mime-Version: 1.0

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Couldn't disagree more with the negative comments re: Tefzel vs. "ordinary
PVC" insulation.

Overheat a PVC insulated wire, even moderately, and the PVC will melt
through. Overheat it a lot and it will burn. Solder a relatively heavy gauge
wire with PVC insulation and the PVC will melt back from the solder joint.

Tefzel insulation will not.

Pull a Teflon insulated wire against a sharp metal edge with a bit of
tension (inadvertently, of course) and the Teflon will cold-flow enough to
eventually cut through. If said metal happens to be at some potential other
than the conductor in question - like ground perhaps - you will get some
fireworks until the circuit protection (fuse or breaker) operates. This is
one of those areas that standard automotive practices don't belong in an
airplane.

The cost of Tefzel is far less than the cost of a mishap created by poor
wiring practices. Incidentally, though the B-1 (a project I was involved in
throughout both the A and B models) was originally wired nearly exclusively
with Kapton insulated wire because it was quite thin and light-weight. In
all subsequent wiring retrofits, the use of Tefzel insulation was mandated
as a safety issue. I figure if it's good enough for the B-1, it's good
enough for my Lancair.

Dan Schaefer


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