Wires and such

[David M Parrish]

> From:          cloud at peaches.ph.utexas.edu (tom cloud)

> Buy your wire from Newark, Mouser, Digi-Key, etc.  I'd stay away from
> the wire from auto parts houses and Wal-Mart -- unless I needed it

It's always a good idea to buy quality wire. In aircraft, the norm 
now is teflon covered wire with fine strands plated with either tin 
or silver. Perfect for engine compartments, since teflon melts at 
such a high temperature and won't burn.

> The catalogs will list the temp rating of the insulation (generally,
> the higher the temp, the stiffer it is).  Be sure the wire is plated
> and get the highest/smallest number of strands so it'll be flexible.
> ** Don't ** use solid wire !!!  It'll break.  Don't drape the wire
> across exhaust manifolds, exhaust crossovers, EGR, etc.  Cover the
> ends with heat shrink or such to keep crud from wicking up under the
> insulation into the wire.

Good advice.

> Really ought to avoid crimp connectors.  Should solder all connections.

Have to draw the line here. In aircraft, which usually have higher
vibration levels than cars and electrical failures are _much_ 
more serious, crimped connections are the norm. The problem with 
soldered connections is the narrow trasition point from solder to 
free strands. At that point, the wire can't flex very well, so 
vibration tends to crack the strands. The point with crimp connectors 
is to use high quality connectors (like Amp) and a good crimping 
tool.

---
David Parrish
Don't ask how much it
costs to wire an airplane...