Aircraft Electrical wire vs quality automotive?

[Blue Chips]

What is the difference between these?

Not talking Harbor Freight wire but quality automotive electrical wire.

Thanks for any input.

[Mike Switzer]

I don't know if there are other differences, but the jacket is thicker on a lot of auto wire - although in recent years several auto manufacturers have been using thinner jacketed wire for control wiring.

[CarlOrton]

Current aircraft wire is usually tefzel coated, which won't kill you as quickly as other insulation products when burning. Electrically, no real diff.

[Blue Chips]

Thanks Guys,
Carl, that was what I was trying to recall, recalled it was something about the shielding.
Been many years since any aircraft wire was use, is it pre-tinned as well?

[FlyingRon]

You don't want to use shielded wire when it isn't called for and you want to use it when it is. That's not the issue. The issue is being assured that the parameters you want for the wire have been met. One, as Carl points out is insulation toxicity/flamability. The other is making sure you have the right electrical characteristics (which often means for the UHF stuff that our transponders, DME, and soon ADS-B surf uses, the proper shielding). Wiring falls under one of those "acceptable data" things. Like our nuts and bolts, usually MIL-SPEC, but again it's important to use the right wire, not just an aviation grade/MIL-SPEC wire that may be wrong.

[rwanttaja]

You don't want to use shielded wire when it isn't called for...

Ron, is this primarily a weight/cost issue, or is there some some other factor?

Ron Wanttaja

[Jim Heffelfinger]

This might be a bit of help.
http://www.vision.net.au/~apaterson/...wire_types.htm

The wire is commonly different, as in marine (ABYC - USCG) wire, the strands are individually tinned and have a higher strand count per AWG than automotive wire. Tinned - corrosion resistance - high count strands for vibration fatigue resistance. Outer jacket types are covered well in the above link.
Jim

and/or here...http://www.eng-tips.com/viewthread.cfm?qid=248263

AC 43.13 chapter 11 covers some fundamental issues.

[CraigCantwell]

Ron, is this primarily a weight/cost issue, or is there some some other factor?

RW: Weight, bulk, flexibility and cost all play into it. Weight goes up due to diameter change. The diameter change causes a jacket change which changes weight per length on top of the shielding weight. The more layers you add, the less flexible the wire becomes. The more you increase the od of the wire, this increases bundle diameter, which changes bundle flexibility, pass-thru size and bend radius as well as changing bundle installation hardware. This all impacts allowable bundle temperatures too, if you have to deal with enviromental limits in an installation. Reduce the bundle flexibility very much and you can create vibration induced harness or hardware failures.

Shielded wire costs more to procure and more to properly install, along with additional costs for proper grounding hardware. Something else too, when you only shield a bundle and not individual pairs, you now have to take into account signal levels and current types into account when designing the wire runs. Bundle shielded harnesses do not like to have AC and DC and low level signaling mixed within the bundle. It's a recipe for crosstalk, data transfer, circuit coupling and phantom voltages and loads.

Design, fabricate and install using best practices and you will greatly reduce the chances of creating a headache for yourself in the world of sparks and data.

[Kingaero]

As an A&P that services light sport and experimentals auto wiring over time can suffer from "black corrosion syndrome". In aviation having the wire tinned prevents this. I can't say how many times I have had to chase an electrical issue only to find a bad wire at a connection. Sometimes the wire was too short to cut back where the corrosion stopped.

Some of the planes I have serviced with aircraft wire are 40+ years old. How many autos last that long without a restoration, including wiring?

Spend the extra and use MIL spec wire.
Mk

[FlyingRon]

Ron, is this primarily a weight/cost issue, or is there some some other factor?

Introducing ground loops and if you're running much more than DC or perhaps voice audio through it, you're likely to introduce impedance issues.