Introduction

This is a guide on the technique on how to terminate wires for a Garmin Avionics Install.

This is not approved material and all work done on aircraft should be done by certificated individuals per the appropriate manual.

This guide covers the use of a twisted pair wire but the technique is applicable to any shielded wire.

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    • DMC crimpers with appropriate turret

    • Wire strippers

    • Flush cuts

    • Razor

    • Fine tip sharpie, or label printer for wires

    • Heat gun

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    • Wire

    • Shield braid

    • Heat shrink (2 pieces), at least one piece white

    • Environmental splice

    • Pins

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    • Interior wires- where the signal is passed through

    • Outer layer of insulation

    • Shielding- a braid inside the wire over the interior wires. This protects the signal from interference or interfering with other signals. The shielding is terminated to a ground

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    • Expose about 1.5" of shield by removing outer layer of wire.

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    • Remove shielding to expose wires

    • Option 1: unbraid shield and the cut away from wire

    • Option 2: carefully cut shield away without nicking the interior wires

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    • Cut a 0.25" long section from outer layer of the wire about 2.5" from the end of the wire.

    • This accomplished with a razor. A new razor will cut more easily through the insulation but can also cut through the shielding. A dull razor is harder to cut with but also more forgiving to mistakes.

    • If the shielding is cut through and the interior wires nicked there is a high potential for a short to ground and that section of wire must be cut off and the wire must be restarted.

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    • Insert the environmental splice over the cut shielding block and insert the shield braid into it. The solder ring must go over both the exposed shield and the braid.

    • Insert a piece of heat shrink over the end of the wire where the shield and outer insulation is cut. This will protect the end of the wire

    • Heat the splice and heat-shrink with a heat gun. Ensure the solder flows in the splice soldering the braid to the shield.

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    • Strip wires appropriate length - detailed in next step

    • Crimp terminals to wire

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    • The wire strip length should by just barely longer than the barrel (where the wire goes) of the crimped contact

    • First picture shows a correct termination

    • Second picture shows to long of strip on wire

    • To make sure the wire is stripped long enough the conductor strands should be visible in the witness hole circled in the third picture

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    • Add heat-shrink with wire number added to it to identify wire after install

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    • Push pins into connector, the should lock into place and need a special tool for removal

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    • Crimp ring terminal to shield braid

    • Install ring terminal to designated grounding location. Often the connector back-shell.

    • This step is done last after all wires for a connector are installed and back-shell is assembled on connector. Sometimes a separate ground lug needs to be installed onto the back-shell.

    Love it! I got a bunch of this wire for free and learned (completely on my own at age 13) that these tools and a whole lotta care with the blade were the only way. One thing you could add to the recommended toolkit that I find essential is a hooked and/or straight pick, or at least a thumbtack to straighten out the braided shielding. It's a pain, very tightly packed and stiff. cutting the jacket lengthwise is the most tedious part. You want a brand new razor sharp point and a light, gliding touch just scoring the jacket halfway through and then zip it off from the long end. Going radially, yeah, slightly dull razor is nice because that braid is taught and thin; doubly easy to cut through because of less consistent and more applied cutting pressure going around the jacket. Nice article.

    Brent Dennard -

Wieli

Member since: 09/01/23

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