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Joining two shielded cables

georgemohr

Well Known Member
Hi all!

Let's say you have two 22-4 shielded cables coming together inside the airplane. There's no need to make these removable via a connector, and the location is not easily accessible in the future.

There's probably a dozen methods of joining these cables. What's your favorite?

Thanks!
G
 
Solder sleeve

Hi all!

Let's say you have two 22-4 shielded cables coming together inside the airplane. There's no need to make these removable via a connector, and the location is not easily accessible in the future.

There's probably a dozen methods of joining these cables. What's your favorite?

Thanks!
G

If it's not coming apart, solder sleeves. Join the braids first then cut the wires to length and join them. Remember the heat shrink on each plus one over the entire joint.
 
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First, I would try to avoid such situation that I have to splice them together and perhaps run a new cable that is of the correct length.
But if that was not feasible, I would connect the wires using D-sub pins, covered by heat shrink and connect the shields using a heat shrink solder on each side joined by a piece of wire.
 
First, I would try to avoid such situation that I have to splice them together and perhaps run a new cable that is of the correct length.
But if that was not feasible, I would connect the wires using D-sub pins, covered by heat shrink and connect the shields using a heat shrink solder on each side joined by a piece of wire.

I agree, if possible, just run a new cable the correct length. Splicing 2 wires together will work, but looks tacky (please don't look in my airplane).

I would follow the Garmin install manuals as a reference and try to keep the unshielded portion less than 2-3inches, even though you are electrically connecting them with a piece of wire. The inside wires/signal is the water, and the shield braid is the water hose, so too big of an unshielded area starts to let the water out and the dirt in.
 
First, I would try to avoid such situation that I have to splice them together and perhaps run a new cable that is of the correct length.
But if that was not feasible, I would connect the wires using D-sub pins, covered by heat shrink and connect the shields using a heat shrink solder on each side joined by a piece of wire.

This was my going-in plan, but was wondering if anyone had a super cool idea I hadn't thought of.

For context, our tail cone is wired with a few feet of extra, and our panel harness is wired out to the wings and back to the mid point of the tail cone. So we need to join up 3 shielded runs at that point. I'd rather not disassemble the harness just to avoid these joins if there's a quality way to mate them. I do like the Dsub pin approach.

-G
 
Before I retired, the company I worked for typically would "daisy chain" a shield wire from one shield to the next with one wire going from the last (or first) shield to the contact (male or female pin) in the connector. (Typically using RayChem zapsplice for space flight and just tinning the shield and wire then soldering together with heat sleeving over the connection for ground support equipment.)

If that is good enough for multi-million dollar spacecraft, then it is good enough for my airplane.
 
I have done an in-line splice of shielded wire by prepping each end by exposing an inch and a half of shielding on each end with 2 inches or so of interior conductor wires exposed. Then I took about 5 inches of large heat shrink and 4 inches of spare shielding and ran it down one side prior to splicing. Then I soldered each interior wire via conventional soldering covered in heat shrink. Then I slid the extra shielding back over the spice and soldered it on each end over the original shielding. Followed this with the large heat shrink covering the whole splice. This method keeps all spliced conductors 100% covered in shielding. The splice area isn't as flexible as the original cable so it should be done in a straight section. For spare shielding I use tinned copper braid that comes in different diameters. Like Garmin specifies for over-braiding of certain wire harnesses. As shown in photo below. The tinned copper braid is equivalent to the braided grounding strap they sell and it can be opened up on one end with a point object or pencil so wire can be inserted.
 

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I’ve done very little wiring on my -4, but have done some. I had no idea you could terminate two wires to 1 pin like that. Learn something new everyday.

John

But be careful. If you ever have to extract that double-wire pin you will be cussing.
 
But be careful. If you ever have to extract that double-wire pin you will be cussing.

Agree with the above, and those pins won't normally accept 2 22ga wires, a single 20 gauge is max, almost impossible to get 2 22 ga wires in there, 2 24ga wires will fit but is still a tight fit.
 
Agree with the above, and those pins won't normally accept 2 22ga wires, a single 20 gauge is max, almost impossible to get 2 22 ga wires in there, 2 24ga wires will fit but is still a tight fit.

With apologies, those were 24 gauge can bus wires. Walt is 100% correct the fit is tight.
 
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