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For spam cans, wiring has
to meet various milspec's to pass muster, but our certificates say
"experimental," and there are no rules specifying what type of wiring must be
used.
That said, I've used mostly
(90%+) tefzel-insulated, milspec wire in my airplanes (3rd in progress), but
there are places where it makes sense to go with other types. Color-coded,
multi-conductor cable is virtually impossible to come by in milspec wire, and
there are lots of nice Belden cables out there at reasonable cost that do a good
job. Yes, they're PVC insulated, but even those pass the VS-1 flame
test. Besides, these are low-current applications that are fused at
something like 1 to 5 amps. In the event of a complete melt-down of such a
circuit, you'd probably have a hard time even smelling the insulation
by-products.
Interestingly, quite a
few PMA parts I've received have come supplied with PVC-insulated wire and
cable. Autopilot cables, RG58, and so forth. The PVC-insulated wire
is much cheaper, and much more pliable, which makes it a lot easier to work
with. For battery cables, try a welding supply place. The good
quality welding cable is much more pliable than the tefzel-insulated stuff, and
runs about 1/6th the cost in 2 ga to 2/0.
One caveat -- I wouldn't
use teflon-insulated wire. The native teflon "cold flows" easily, so wires
pressed together over time may push through their insulation and contact each
other or other metal parts.
Jim Cameron
Legacy in the works
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