Electrical Plugs at Wing Roots

[jmodguy]

Cherry
I am using DB9 (computer serial port) connectors at my wing roots. These are very affordable (cheap) and easy to put in small places. You can get a bag of 10 for a few bucks at Frys or similar electronics store. Be sure to use mil spec machined contacts. We use these on mil aircraft. The rolled contacts can be iffy at times and it is harder to get consistent crimps.
I am using a 4 wire unshielded cable in my wings. This allows for wingtip wires for nav, strobe, ground, and sync.
I used a 3/8" OD polymer tube from Lowes as a conduit to route the cables to the wingtips. I cut a small hole where the OAT and magnetometer wires head to the fuse. Plenty of room for the quad cable and 4 wires from my magnetometer.
As for using the shield in a cable (term for a multi wire jacketed "wire") as ground, I would NOT recommend this. The shield is designed for noise mitigation (EMI), not current handling. Some of the tefzel cables use a silver plated braid that corrodes rather easily and you would not want that to be carrying any current.
Do you need Tefzel wire? nope. a lot of your car wiring is not tefzel, even in the engine compartment. The reason mil aircraft use teflon based jackets is the noxious fumes PVC puts off when it burns. Tefzel is pretty nasty too, it just has to get hotter.
I have been wiring military and civil aircraft since 1980. I currently work for a DoD contractor in the wiring and interconnect department and can go on for a bit about wiring best practices and techniques...

Oh - the connector on the fuse should have female contacts so you do not inadvertently short any pins (there will be power on one or more).

[efwd]

Thanks Jeff. I never understood why the instructions instruct what end of the wire the female and male connectors go on. Now While wer on the subject Ill hijack Carls thread since he will want to know as well. Without spending $150 on a crimper, where or how would one get the 6AWG battery cable connector crimped onto the cable. I bought a really nice multi head ratchet crimper but it turns out that it wont handle 6AWG
Eddie

[Cherrybark]

Jeff,

Thanks for those comments. Being retired software, I've been surrounded by DB9 connectors, just never thought of them in this context. When using shielded, do you solder or connect the braid to the cases?

I saw your idea of using the 3/8" OD polymer tube in an earlier thread. Promptly returned my unopened bags of official conduit and bought a nice length of poly for a fraction of the cost. Great idea, and I like the smooth walls.

Do you know offhand if the magnetometer is doing the analog conversion at the unit and sending digital in the wires? I would think digital transmission would be less subject to noise. If digital, I would be less hesitant to use non-shielded, 4-strand for the lights and run the magnetometer wires through the same spar.

I'll be happy to move away from Tefzel and enjoy the wider variety of color choices. Would you go so far as to use Tray Cable or is tinned better?

[Cherrybark]

Floog,

I really appreciate that specific recommendation for wire. Excellent to have rather than spending hours digging through on-line catalogs.

[Dave S]

Carl,

I thought about making a junction at the wing root; but ended up going simple and cheap while reserving enough of a service loop at the root to permit the addition of connectors or a junction block if I some day needed to remove a wing or two. So far, 8 years of flying and I haven't found any reason to remove a wing...but there is enough wire in the service loop to cut and install connectors.