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Permalink Reply by Jim and Amelia Isaacs on January 20, 2025 at 6:05pm

I have a background in aircraft manufacturing. I’ve not seen nor used heat shrink connectors in commercial or military aircraft design or manufacturing, only aircraft grade mechanically secured connectors. That said, I confess I have used one or two on my 701, but as an exception. I’ve had no issues with the few I used thus far (five years, 200 hours in service). Otherwise it’s full length runs from power buss bar to circuit breakers then on to the device requiring power. Ground buss only (no local airframe grounds) using mechanical force connections and full length runs same as in power runs. Have you downloaded a copy of The Aeroelectric Connection by Bob Nickolas? Leave a bit of extra length (service loop) wherever and whenever possible because it’s not if, but when, you will need to troubleshoot or relocate something. Dress and route your harness runs, mark each wire whenever possible, and sketch out your wiring diagram as you go. What engine? Is there an install manual for its electrical requirements? The ignition system requirements must be clearly understood. For example, if shielded wires are to be used from Ignition device to switch, must the shield be terminated at both ends? Is a shielded twisted pair OK or must the two wires be separated and individually shielded? Seek the experience of others who have built the same aircraft using the same engine.

And have fun!

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Permalink Reply by Peter Eiberger on January 21, 2025 at 3:47pm

I highly recommend you pick up a book called: The Aeroelectric Connection by Bob Nuckolls.  He does a good job explaining how connections should be made and what materials and methods are acceptable.

The book is $40 from amazon. 

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Permalink Reply by Jim and Amelia Isaacs on January 22, 2025 at 4:17pm

Alternatively, Bob provides a free download pdf version here http://aeroelectric.com/Connection/R12%20Searchable%20Merged%20Chap... 

either way, highly recommended!

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Permalink Reply by John Burns on January 23, 2025 at 10:36am

The heat shrink connectors are excellent for automotive where there is a lot of moisture exposure.  My preference for aircraft is high quality Nylon double crimp connectors.  These have a crimp for the wire and another for the insulation.  They are best installed with a ratcheting crimper that guarantees a proper crimp.  Stein Air has some good videos about these connectors and crimpers.  I bought my crimpers from Aircraft Tool and Supply and my terminals from McMaster Carr, but other sources may be cheaper.  

(57) 002. Terminals: Basic overview of aircraft electrical terminal...

015: CRIMPING STANDARD AVIATION WIRE TERMINALS USING SIMPLE CRIMPER

Just my process.  Your results may vary.

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Permalink Reply by Gary Welch on January 24, 2025 at 3:36pm

PIDG wire connectors (as John noted above) that crimp both the wire and the wire  insulation are the preferred connector for aviation.

Conventional wisdom is that soldered joints in electrical wiring pose a risk of failure due to the excessive vibration in most aircraft (as apposed to automobiles).

While you'll hear a lot of different opinions on this subject, there is definitely some logic here.

I guess the one variant would be if you are using a Viking auto engine where vibration is typically less than most opposed cylinder aircraft engines. Still, if it were. My plane I would use the PIDG connectors. The cost difference is pennies. 

Also, if it were me and I was interesting in buying an aircraft and saw automotive connectors, id probably walk away because I would wonder what other penny pinching went into the aircraft. Plus the never-ending concern over electrical problems.

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Permalink Reply by Bob Simmons on January 25, 2025 at 10:09pm

Heat shrink connectors are acceptable, as long as they're of a suitable type, and they're used in an accepted manner. I've used them tons of times, for both military and civil aircraft. See AC 43.13-1B, Section 13. Note that deals with inspection and repair, not manufacturing. While there's nothing to prevent you from using such splices in a build, it's not the most preferred method. But, being homebuilders, we don't always get the same choices that commercial manufacturers do, unless we build all full length wiring harnesses ourselves. Since we use prefab harnesses or partial harnesses, splicing is required.

I will second, third and fourth the suggestion you get The Aeroelectric Connection. I personally consider it mandatory.

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