Wire sizes

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

Use the wire charts in the AC 43.13 to determine wire size and fuse or
circuit breaker. Remember, you're fusing for the wire, not the load.

http://rgl.faa.gov/Regulatory_and_Gu...E?OpenDocument

Jim

On Sat, 26 Jul 2008 21:52:30 -0500, Fred Blair wrote:

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

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

I wired mine with 13 amp UK triple flex power cable, denominated Earth
(green/yellow stripe), Live (brown) and Neutral (blue).

The Earth wire is common and fitted with a 4 amp fuse at the batteries.
Live connects one battery to the radio (Filser ATR-500) and T&B via a 4
amp fuse at the panel. Neutral connects the other battery to both varios
and the GPS via a 4 amp fuse at the panel. Both switched by a two pole
push-on/push-off switch on the panel.

I split the circuits so that, if forced to fit a transponder, I can put
it, radio and T&B on one side and keep the varios and GPS separate. If
push comes to shove, I care about having power for the varios and GPS more
than I do about powering the rest. If I need a more flexible setup in
future I can achieve that simply by replacing the switch and fuses on the
panel.

Speaker?

One side of a piece of medium quality dual shielded cable.

This is the cabling you'd use for a stereo interconnect between CD player
and the preamp or between preamp and power amp. Its a figure 8 cable, each
side being about 4 mm (5/32") in diameter.

Push to talk?

Lightweight 3 mm (1/8") diam shielded cable.

Boom mic?

Other side of the speaker's shielded cable. The speaker enclosure is on
the cockpit wall alongside me and doubles as the boom mic mount.

HTH


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot

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

On Jul 26, 7:52*pm, "Fred Blair"
wrote:
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


Check the FAA advisory Circular

Circular and elecrical supplies on my installation supplies web page

http://www.craggyaero.com/installation_supplies.htm

Richard
www.craggyaero.com

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

I gave a presentation on this subject of avionics wiring at the 2007
SSA convention. See http://derosaweb.net/aviation/presentations to
download the presentation. It looses a little without my voice over
but you will get the main points. Darryl - Please critique this if you
get a chance.

Couldn't agree more on the use of tefzel. It is an FAA requirement,
not an option. I have seen lots of incredibly lousey glider wiring so
I am on a "jihad" to get the word out to do better. Remember that
your local DIY or electronics store does *NOT* have an aviation
aisle. http://wingsandwheels.com/page5.htm has a good assortment of
Tefzel as well as places like Aircraft Spruce and Wag Aero.

Using rules of thumb on wire gauges can lead to mistakes. Should the
main line from the batteries to the instruments be 12 gauge?
Smaller? Larger? It all depends on the load. In a airplane (versus
an glider) this can go from little to massive, so determining the
gauge needs some careful analysis. Luckily the load of the avionics
package in a typical glider is fairly standard (vario, computer/
recorder, PDA, transceiver) so 12 gauge is generally considered OK.
I haven't analyzed the typical loading of a transponder so cannot
comment further.

Other control (ptt, gear warning) and audio (speaker, microphone) are
low current affairs so I typically using 22-24 gauge which you can
find in multiple wire bundles.

Finally, my disclaimer. I am *NOT* a FAA certified avionics
technician. I cannot sign a log book for a repair or perform the
installation. You need to get your work done by, or overviewed by, a
FAA licensed tech. Nuff said.

My $0.02.

- John DeRosa

On Jul 28, 9:10*pm, ContestID67 wrote:
I gave a presentation on this subject of avionics wiring at the 2007
SSA convention. *Seehttp://derosaweb.net/aviation/presentationsto
download the presentation. *It looses a little without my voice over
but you will get the main points. Darryl - Please critique this if you
get a chance.

Couldn't agree more on the use of tefzel. *It is an FAA requirement,
not an option. *I have seen lots of incredibly lousey glider wiring so
I am on a "jihad" to get the word out to do better. *Remember that
your local DIY or electronics store does *NOT* have an aviation
aisle. *http://wingsandwheels.com/page5.htmhas a good assortment of
Tefzel as well as places like Aircraft Spruce and Wag Aero.

Using rules of thumb on wire gauges can lead to mistakes. *Should the
main line from the batteries to the instruments be 12 gauge?
Smaller? *Larger? *It all depends on the load. *In a airplane (versus
an glider) this can go from little to massive, so determining the
gauge needs some careful analysis. *Luckily the load of the avionics
package in a typical glider is fairly standard (vario, computer/
recorder, PDA, transceiver) so 12 gauge is generally considered OK.
I haven't analyzed the typical loading of a transponder so cannot
comment further.

Other control (ptt, gear warning) and audio (speaker, microphone) are
low current affairs so I typically using 22-24 gauge which you can
find in multiple wire bundles.

Finally, my disclaimer. *I am *NOT* a FAA certified avionics
technician. *I cannot sign a log book for a repair or perform the
installation. *You need to get your work done by, or overviewed by, a
FAA licensed tech. *Nuff said.

My $0.02.

- John DeRosa

John, my only comment is I'd encourage people to look for the best
quality *ratchting style* crimpers they can afford - for both Coax and
for wire connectors. Using these tools often produce a night and day
difference from non-ratchting style crimpers, the cheaper ones of
which cannot possibly produce enough jaw pressure to create a correct
connection. The brand name ratcheting crimpers tend to be just better
engineered and the ratcheting mechanism helps ensure the correct
pressure is applied (as long as you use the right connector for the
wire gauge).

There is a good article on crimpers for use in aviation wiring at
http://www.aeroelectric.com/articles.html (and he is comparing an
already better ratcheting crimper than many people would use with an
even fancier one but the good thing is he is showing in detail what a
proper crimp joint looks like). That web site also has lots of other
interesting information and informed opinion on aviation electrics.

While none of this is rocket science by any stretch, I still worry
that if people are having to ask basic electrical questions then the
best thing may be to find an A&P who can show you how to do
professional wiring and look over your shoulder at your work. And to
get a really professional job it might turn out to be cheaper to pay a
trusted A&P to do it than buy special tools, a stock of Trefzel wire,
etc. I know finding that A&P may be the issue in many cases.

Darryl
(Just an anal retentive glider pilot/owner and electronics geek, and
not an A&P)

On Jul 28, 11:38*pm, Darryl Ramm wrote:
John, my only comment is I'd encourage people to look for the best
quality *ratchting style* crimpers they can afford - for both Coax and
for wire connectors.

I bought this crimper (http://www.westmountainradio.com/PWRcrimp.htm)
a couple years ago to make up the Power Pole battery connectors
(http://www.flyrc.com/articles/using_powerpole_1.shtml and
http://www.westmountainradio.com/order_RC.htm#ppc) I use for making up
in-cable connections. Recently I added the die assortment and have
had very good results making up antenna cables and installing various
terminals.

-Tom

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

For power especially, use ONLY Tefzel wire!

Here we are again. Is Tefzel the best stuff to use these days? Yeah,
pretty much, no disagreement there. Is it important to use good
materials? Yup, pretty important.

Is it the only stuff to use, the stuff that you must use? All-caps and
exclamation point aside, it depends. I have only a couple of always/
never rules about aircraft wiring, and they're about fuses, not
Tefzel.

Comparatively speaking, I happen to think that how you wire things is
more important than what you wire them with. Given the choice between
organized bundles, well supported, appropriately fused, protected from
abrasion, and kept away from moving parts, all executed in Electron
Hut automotive wire, versus a rats nest of unmarked white Tefzel going
every which way, I'll take my chances with the Electron Hut system.
But, that's just me.

I've written that all before. But here's some new information content:
Be careful about drilling holes around wiring bundles, especially
where you're drilling metal. In one of my current projects, we've
found chips of aluminum swarf embedded in the Tefzel insulation of
wires pretty deep within wiring bundles. We undertook a program to
unwrap every accessible wiring bundle and clean out the chips, and now
are taking special precautions to keep chips out in the first place.
It's certainly a thing to think on.

Thanks, Bob K.