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Some funny stuff found behind a panel (and good and bad wiring practices)

This is behind the TB20 circuit breaker panel. Can anyone identify it? It looks like a thermal fuse

And who had the bright idea to hide two fuseholders there?

AFAICT the above is original Socata stuff…

But this is a (very commonly seen) bodge done by some avionics shop – wires run too tight so the assembly cannot be tilted back as intended.

In fact I know of one TB20 whose LH instrument panel was wired solidly in place do it could no longer be tilted

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

This is behind the TB20 circuit breaker panel. Can anyone identify it? It looks like a thermal fuse

Looks like a simple push on terminal with heat shrink to insulate it.

FAA A&P/IA
LFPN

Oh yes – that must be it.

The two fuseholders bundled into the harness are still quite funny… It takes a lot of effort to reach them, starting with undoing a number of self-tapping screws.

Administrator
Shoreham EGKA, United Kingdom

You think that lots bad. Take a look behind the panel on a permit aircraft and you’ll find every bodge known to man. To be fair a lot of G A aircraft are no better. Given the average age of some of the C of A aircraft and most electrical work is not done by an “electrician”/avionics engineer its no surprising. Splice after splice after splice. Saying that the quality of some of the wiring that is on new aircraft isn’t good out of the factory. I work on new business jet and the quality isn’t there. I used to work for British Aerospace building airliners and the wiring was pretty good.


This was what I was confronted with when I removed the instrument panel on my Europa. I’m now doing a re-wire and new panel

Near Luton

I stuck a camera up behind my panel last weekend (basically looking to see what kind of space I had to replace the fuse box with circuit breakers), I think refreshing the wiring is going to be one of the projects carried out at permit revalidation time, there’s decades old leftovers in there I’m not sure are actually connected to anything. Not quite as messy as the Europa pictured above but not to my satisfaction.

Andreas IOM

I sometimes wonder how much weight would be saved by pulling out the dead KCS-55 slaved compass system wiring I still have in place. Probably only a few kg at most… not worth doing, and some of the wires become useful in the future.

I have seen worse than the above in one kitplane, with wires wrapped around a (clear plastic) fuel pipe. That was a brand new build. I don’t know why the builder is not given better instructions on the real basics like that, but then laying out the panel and wiring it makes up the bulk of the required “51%”

Administrator
Shoreham EGKA, United Kingdom

Some homebuilts will have neat wiring:

Avionics geek.
Fairoaks. EGTF

Interesting that you use that braided sleeve… It makes a neat job and protects the wires from abrasion, but I find it a real bugger to slide on, if the harness is of any significant length.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

It makes a neat job and protects the wires from abrasion, but I find it a real bugger to slide on, if the harness is of any significant length.

Well, that’s the advantage of a homebuilt. You just don’t have to economically justify labourintense means…

mh
Inside the sky.
EDXE

Peter wrote:

It makes a neat job and protects the wires from abrasion, but I find it a real bugger to slide on, if the harness is of any significant length.

One trick is to push a small wooden ball through the sleeve – drill a hole in the ball, and use it to pull a few threads through the sleeve, which you later can use to pull through the wires. Always make sure one thread remains until the last wire is done, you can always use that one to pull though more threads.

(I do this when sleeving for a PC build, where runs are quite short, but this should work for any length)

Biggin Hill
11 Posts
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