REFLECTOR:Wiring

Wayne Lanza reflector@tvbf.org
Thu, 23 Oct 2003 20:17:16 -0400


Regarding the type of wire to use...

  You can basically use any type of wire you want. The Tezel (MS22759) 
is great stuff
to work with, it strips well, has great abrasion resistance and has 
fine, plated strands.
The recent discussions regarding vapor hazards when wires overheat 
misses the point.

  A properly designed and protected system is less likely to have this 
problem... For the
sake of argument you can easily induce this problem by improper 
grounding. How?
By not matching the capacity of the ground return to the total of all 
the loads connected
to it - have seen it done, especially behind the panel. In other words, 
you can use all of
the breakers you want and the best wire in the world and still make the 
grounds glow
if they are overloaded.

  Another reason for using wire like 22759 is the wire itself. The 
strands are tin plated
and if properly terminated (with the proper terminals) will not corrode 
or oxidize. The
next and most important consideration is the stranding itself. This 
type of wire employs
many fine strands, and in the larger wire strands of strands that are 
designed to flex
and give with stress and vibration. The fine strands also crimp 
better... As I understand
it, the actual copper base metal of this wire is also less likely to 
work harden and break
like coarse wire, i.e. house and automotive wire.

  I can't tell you how much wire we use to typically wire a Velocity, it 
varies a lot. But I can
tell you that we have seen many aircraft with wiring problems and 90% 
of them are due
to the wrong stuff being used in the airplane. You get what you pay 
for...

  My comments are not opinions but product of practical experience from 
my efforts at
Velocity and 25 years as an electronic test engineer. I am a contractor 
at the builder's
center and have designed & manufactured electrical systems for 
experimental aircraft
for the past ten years. We have tried hard for many years to address 
the typical problem
areas associated with the electrical systems in composite aircraft. I 
hope that you find
this information useful and that I have been of some help.

Best Regards to all,
Wayne Lanza
Composite Design, Inc.