On Jul 27, 5:29*am, "01-- Zero One" wrote:
Fred,

1. For power especially, use ONLY Tefzel wire! *This is aircraft quality
wire with Teflon jacket that melts at a much higher temp than regular
wire and does not give off the toxic smoke when it overheats that PVC
coated wires do. You can buy it at Wings and Wheels. *I would use 14 AWG
wire to minimize power losses (or maybe as small as 16 AWG).

2. ABSOLUTELY mount a 3-5 amp fuse on each battery!!!!! *If there is a
profound short in the power wiring, this fuse will blow and you will not
be sitting in a puddle of melted plastic and red hot wires.

3. For all other wires (boom mic, PTT, and speaker), I use 22 AWG single
core shielded Tefzel wire in the harnesses that I build.

4. I like to use a master switch and fuses on the instrument panel and a
good BUSS system for ease of troubleshooting and visual inspection.

Larry "the _real_ cable guy" Goddard

"Fred Blair" wrote in message

:

What are the recommended wire sizes for use in a glider?

Power? *The only power is a radio and Cambridge Model 20 and LNav

Speaker?

Push to talk?

Boom mic?

Thanks for sharing your expertise,

Fred

Yes, use Tefzel. However Tefzel is not Teflon, althought they are
related and bother are trademarks of Dupont. You want Tefzel aviation
wire, not Teflon coated wires you might find at electronic supply
stores. Tefzel is more abrasion resistant and tougher than many Teflon
insulated wires. Another advantage of aviation Tefzel wire is is it
fully tin plated, which avoids corrosion that sometimes happens to
untinned copper wire.

Personally I would put an aviation circuit breaker right on the
battery, 5 Amp or so - no spare fuses to have carry around or loose.

22AWG multi-strand is available and woudl be less prone to damage from
the single strand breaking due to flexing or vibration (uckilly not
much of that in gliders).

Chief Aircraft is also a good source of Tefzel wire in the USA see
http://www.chiefaircraft.com/airsec/...pply/Wire.html

You should be using crimp connectors on this wire not soldering it.
Use good quality, brand name (3M, Amp, etc.) crimp connectors, nylon
not PVC jacketed, don't mix connector brands/models where they have to
mate (e.g. there are subtle differences in blade connectors), don't
use junk from a local auto parts store. Good connectors are available
from many electronic supply companies. And using a good quality
ratchting crimper. See previous threads on this.

Previous posts mention using different types of wires. It s generally
cosideered bad form to pull wires with different insulation jackets in
the same harness/cable run. This is mostly an abrasion issue in high
vibration environment or where pulling the cable bundle is a challenge
so may never actually casue problems in gliders. I know different
glider manufactures still do this but I cringe when I see a mess of
Tefzel, PVC, rubber speaker cable etc. trying to pass for a wiring
harness. A nice wiring job should look ultra tidy, use nylon cable
ties, have enough slack in it at places so it is easy to connect/
install without damaging it, etc. Also think ahead about what might
happen if you add more avionics/toys in future. You might want to
avoid using lots of heat shrink to bundle wires since it is harder to
add a wire to in future, and don't use cheap PVC heatshrink, use
Polyolefin its less flamable and more abrasion resistant. You might
want to use color coding or shrink on labels on the wiring to keep
track of things.


Darryl