Grounding shielded wire?
Thanks for the great video about stripping shielded wire, got a couple follow ups, please.
-The GTR-200 ICS only has 2 unswitched inputs, I've got 3, and at Garmin's suggestions I'm using a Flight Data Systems AP-60 Audio Panel to consolidate them. The incoming wires are unshielded, and I'm using shielded wires for noise reduction to feed the ICS and from the AP-60 to the radio. Any good suggestions for consolidating and grounding the shields?
Last edited by Noob builder; 10-01-2013 at 02:37 PM.
There really is no "standard" way to connect the shields together. I assume that the center conductors are crimped to a small end fitting that clicks into an edge connector that is screwed to the rear of the avionics tray for the unit.
One important rule is to only connect one end of a shield to ground. You do NOT want the shields carrying current due to small differences in electrical potential at different points in the airplane. "Ground loops" cause all kinds of hard to figure out noise.
Since the assembled radio connector will likely never have individual pins removed, you could leave 1" of shield peeled back from each wire, twist that up, and solder it to a length of bare solid copper wire layed across the top of all of the shields. Then wrap the end of that bare copper wire under one of the nuts that holds the edge connector to the avionics tray.
That's one idea. Most folks just try to make the wiring neat.
I will lobby that you get some wire numbering tape and use it to put a unique number on each wire, then make a little diagram for your records. Will save you a lot of head scratching when you are trying to figure out why something isn't working correctly next year.
Best of luck,
I disagree with the above post only in one aspect - I peel back the shielding as outlined above, but instead of soldering a piece of copper wire and risking melting through the inner insulation layer, I simply wrap the grounding wire around the shielding then use a piece of shrink wrap over it to keep the grounding wire from slipping off the shielding. No solder, no heat, no way of compromising the inner insulation layer. Otherwise the above post is great advice.
A solder sleeve works well for this application. All you need is a heat gun to melt the solder.
There are many places to buy them, here's on good place. SteinAir
I'm sorry but I have to disagree with you comment. If you re-read the previous quote that you disagree with, the shield is stripped back from the center insulated lead, twisted to form a ground wire(as such) and that ground wire is soldered to the copper wire. Soldering this twisted lead, if done properly, will not heat the insulation of the insulated lead and will not compromise that insulation.
Originally Posted by firstname.lastname@example.org
Also making a solderless connection as you describe, will not provide a perfect ground.(OR a lasting connection)
There are two methods to create a proper electrical connection. Mechanical crimp, preferred in most cases, and soldered (when properly completed)
Wrapping a conductor around another conductor and using shrink tube to hold it in place may work for a short term but time and nature will form corrosion between the two conductors reducing and/or preventing the connection integrity.
For lasting results, always either Crimp using proper avionics crimping tools or solder with proper heat and solder composition.
Bob Doughty A&P
Bob is correct. Soldering is part of my audio profession-- a connection made only with shrink wrap & no solder is not a good electrical connection to start with, and will deteriorate further over time. Oxidation & micro-arcs. Russel Green
Originally Posted by BCAIRPORT