[Amps] Wire

[Pat Barthelow]

The Aviation World is quite in the spotlight on Wiring issues, and undergoing a lot of soul serching on solving tough problems, in aging aircraft wiring, and specialized insulations long accepted, but now questioned, or more exactly targeted for specific uses, such as Kapton, tefzel, and teflon.

 

I Googled Avionics, Wiring and Standards, and got a good selection of current, and older commentary of the problem:

 

http://www.aviationtoday.com/av/issue/columns/perspectives/12872.html
http://www.aviationtoday.com/av/issue/columns/perspectives/12555.html
ASTMF-2369; ASTMF- 2490
http://aero-defense.ihs.com/news/2008/astm-airplane-electrical-wiring.htm
ANM-01-04
http://www.aviationtoday.com/av/categories/military/12727.html
A-D Wiring Issues  listings:
http://findarticles.com/p/articles/mi_m0UBT/is_34_15/ai_78044274/pg_7
Aging Aircraft PPT
www.dixiecrow.org/Powerpoint%20Briefs/Hinton_Aging_Aircraft_Sustainment_DixieCrows.ppt
Scary one here:
http://www.heli-chair.com/wiring_101.html
 
http://www.russellw.com/logbook/vision_for_avionics_interconnects.htm

Re:  ASTM Standards for Avionics wiring tape, and some standards:

Specifications & Standards

FlameGuard™ Pure Silicone Tape meets many or all of the specifications of the following standards: 
     MIL-I-46852, A-A-59163, ASTM D412, ASTM D 119,
     ASTM D150, ASTM D624, ASTM D2148, ASTM D2240.

FlameGuard™ Pure Silicone Tape may also be certified to the following specifications upon request (fees apply):
     Commercial Specification A-A-59163 Type I & II  (Previously MIL-I-46852C Type I & II), Military Specification MIL-I-22444C,
     Underwriters Laboratories Inc UL-510, Boeing DMS2186 Type II, Lockheed Martin MMS J517 & 5-00857, Safe Flight 59562-5
     Systems & Electronics Inc ES7889, McDonnell Douglas Helicopter HS5215, General Dynamics P5384 Type II,
     General Electric A50A493 / A50E112 / P5384, Rohr RMS315, FAR 25.853, CSA 22.2, Premier Farnell Corp 810112

73,    All the best,
Pat Barthelow   AA6EG
Jamesburg Moonbounce Team
aa6eg at hotmail.com

> Date: Mon, 28 Jul 2008 10:21:19 -0600
> From: xxw0qe at comcast.net
> To: km1h at jeremy.mv.com
> CC: amps at contesting.com
> Subject: Re: [Amps] Wire
> 
> Carl,
> 
> I can't say for sure but others have told me that cold flow was the 
> primary reason it was used rather than Teflon. In aircraft usage, wires 
> are bundled and lashed down so creep is a big deal if the wire is lashed 
> to some metal part. I just took some #20ga Tefzel and some #20 ga 
> Teflon wire and doing a totally unscientific test I was able to mark the 
> Teflon wire with my fingernail much deeper than the Tefzel.
> 
> 73, Larry W0QE
> 
> Carl wrote:
> > Larry, is the cold flow performance of the Tefzel better than Teflon?
> >
> > Carl
> > KM1H

> > ----- Original Message ----- From: "Larry Benko" <xxw0qe at comcast.net>
> > To: "Harold Mandel" <hmandel at barantelecom.com>
> > Cc: <amps at contesting.com>; "Rich Schmuke" <rdj at wildblue.net>
> > Sent: Monday, July 28, 2008 11:18 AM
> > Subject: Re: [Amps] Wire

> >> I had responded to Rich last week but I guess he either didn't like my
> >> answer or just wanted more opinions.
> >>
> >> Look at
> >> http://www.welchfluorocarbon.com/techdata.htm#Table1FluoropolymerSelectionGuide 

> >> for more than you probably want to know. I measured some 20 or 22 gauge
> >> twisted Teflon and Tefzel wire a few years ago and couldn't see any
> >> difference other than Tefzel has a slightly higher dielectric constant
> >> (2.6 vs 2.2). Tefzel is not rated to quite as high temperature but both
> >> are plenty high enough. :)
> >>
> >> Also in may last job we used only Tefzel wire in aircraft products. I
> >> think it is becoming more common that Teflon insulated wire. Also the
> >> breakdown voltage is higher than Teflon and the material is harder which
> >> is good for wire that is wound against a surface. Both Teflon and
> >> Tefzel are DuPont registered trademarks.
> >>
> >> 73, Larry W0QE
> >>
> >>
> >> Harold Mandel wrote:
> >>> Rich
> >>>
> >>> [snip]
> >>> Does any know a reason why TefzelR ETFE insulated wire would not be as
> >>> good or better because the dielectric strength is even higher...
> >>> [snip]
> >>>
> >>> A balun will generate heat.
> >>>
> >>> Manufacturers of popular baluns realized
> >>> stations would attempt to load RF into
> >>> huge mismatches and because they wanted
> >>> to reduce warranty claims, went for the
> >>> cheapest solution that would withstand
> >>> heated wires the longest.
> >>>
> >>> While PTFE insulated wire is a common
> >>> choice for commercial balun products there
> >>> are always upgrades in quality.
> >>>
> >>> Why not build such a device and test it
> >>> using your ETFE stuff? Mismatch it
> >>> and report on its ability to handle
> >>> high temperatures.
> >>>
> >>> I for one would be very interested in
> >>> insulation that would surpass PTFE.
> >>>
> >>> Hal Mandel