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danny_galaga

Wiring an instrument panel

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Let me start by saying I used to be an auto electrician, so not too concerned with basic electrical theory etc. What I will need though is some sort of guide, online or otherwise for the conventions of aircraft wiring. And then where to buy supplies like wire? I was looking at aircraft spruce but didn't know where to start!

 

This is for a kit plane if that matters :-) 

 

 

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I used all Tefzel wire (aircraft wire) for mine. I threw away all the automotive wire supplied in the kit and started from scratch. Also any plugs I used for my own wiring harness other than where spades etc are used were all Deustch. Spades and ring terminals should all be double grip and use the correct crimping pliers not those stupid supercheap crap to do the crimps. Breakers are also a must for each power rail you run and of course all radios and EFIS ets should all be fused as well

 

Mark

 

 

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RS components supply PTFE insulated 'harsh environment wire that meets mil-spec. The AC43.13-1b has a section on wiring & electrical. If you are an autoelec, you probably already know that Ashdown Ingram supply good switchgear and stuff as well.

 

 

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Hi nobody, do you have a contact link for aeroelectric. I couldn’t find one. Thanks

 

 

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Let me start by saying I used to be an auto electrician, so not too concerned with basic electrical theory etc. What I will need though is some sort of guide, online or otherwise for the conventions of aircraft wiring. And then where to buy supplies like wire? I was looking at aircraft spruce but didn't know where to start!

This is for a kit plane if that matters

Tefzel aircraft wire is available from Ian's "Clear Prop " shop here in most gauges by the metre.

 

Mick

 

 

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Tefzel wire has a white outer cover. It doesn't come in a variety of colours as does automotive wire which make tracing circuits easier. In order to make identifying and tracing the wires a little easier, I suggest that you buy a few lengths of heat shrink tube in various colours. Put a short length of heat shrink at each end of the wire, and record the colour sequence on a wiring diagram. You can use as many colours as you like, as long as you document the meaning of eeach colour or combination of colours.

 

Here's a link to the Lucas wiring codes which can be used as a standard.

 

http://www.team.net/sol/tech/LucasColours.html

 

 

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Browse    

 

http://www.aeroelectric.com/articles/

 

for ideas, work-arounds and conventions. Buy the real crimp on terminals (AMP are generally available here) and avoid consumer grade stuff. Tefzel wiring is lighter and more heat resistant, usually rated at 600V. There are colours available in the smaller gauges for instrument work. Use a central earthing busbar behind the instrument panel. Jaycar have affordable crimpers.

 

Max.

 

 

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There is also little "slide-on" alphabet things you put on each cable & record the combination ( AACB) to keep it all nice.

 

spacesailor 

 

 

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I used automotive so have colour coding. Yes I know Tefzel is lighter and fire resistant but it is much more expensive and harder to obtain, not as flexible as well as being all one colour. I did use tefzel for engine instruments due to its heat resistance. Grounding and shielding are probably the most important aspects as if you end up with any ground loops, noise from the engine will end up giving you radio problems. I have attached a guide that I think is a good reference "Aircraft Wiring for Smart People". I found it useful

 

Aircraft-Wiring-Best-Practices.pdf

 

Aircraft-Wiring-Best-Practices.pdf

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Several people have said here that tefzel wire  is only available in white and not coloured. 

 

Thats completely incorrect. 

 

Tefzel wiring is available as white, white plus coloured lines and a vast range of single and solid colour with secondary coloured wire.  ( I have several rolls here in front of me now with up to 8 colours in shielded multi core). I also have a heap I got somewhere in the past with complete single colour, one colour with secondary line color). 

 

I got a bunch from aircraft spruce Australian distributer in Brisbane. But I have got it from multiple places on line. 

 

 

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Agree. I have rolls of different colours.  On another point of info a good tip I learnt years ago was about labeling the wires. To do this I write the lable very small in pencil on paper, cut it out and attach to the wire with clear heat srink.  Must use a sharp point on pencil to allow the fine printing text.  Pencil dosn"t fade. If a long wire run I'll lable both ends. Sure makes for easy identification during electrical work. Cheers

 

 

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I have used a Dymo labeller and 8 point font to make ID tags. Takes the worry out of poor penmanship. The wire need to be wiped over with metho to clean off any oily residue before the label is put on and then covered with clear heat shring.

 

 

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The reason for using Tefzel wiring is that if it burns, it does not emit toxic fumes. Who wants fumes of any sort in the cabin.

 

If you can get the varied colours use them, otherwise you need some sort of marking at the ends.

 

If you need to be able to remove the panel it would be a good idea to use the plastic multi connectors available from auto electricians.

 

Always give yourself a bit of slack in the wiring, otherwise you will end up having to extend a wire in the future.

 

The experts say you should run all grounding wires back to one commom ground bus.

 

Fuses or circuit breakers seem to cause arguments. My opinion is that if a fuse blows it is usually due to some problemthat is more than resetting a circuit breaker will solve, so I opt for fuses. They are smaller and lighter. I put a small LED across the fuse, the object being that if the fuse blows, the LED will light, giving me an immediate warning. Be aware though that a multimeter will show the current through the LED, giving the impression that the fuse is good.

 

Common practice is to group all the wires into tidy bundles, but that can lead to higher temperatures and it can also put a "noisy" wire in close proximity to radio wiring. The P lead is one of the noisy ones.

 

The other common practice is to use crimped connectors, rather than soldered connections. Solder is of course the better joint, but you have to ensure that the wiring cannot move close to the solder joint.

 

When you arrange the location of switches, think how you will be using them. so that you don't need your hands to be in two places at once. I have the two P lead switches adjacent to the starter button, but it would have been better to have the button between them.

 

Normally you would have a master switch, feeding the different bus bars through separate switches. In my case I have an instrument bus, a radio bus and a lights bus, all switch and fuse controlled.

 

Most kit planes have a solenoid controlled master switch, but my personal preference is to have a manually controlled master switch, close to the battery and then a master switch on the panel. that only works if the battery is in the cockpit. On my Corby I have a central  separate panel, that can be removed from the main panel, to give access to the back of the instruments mounted on it. It is mounted on flexible panel mounts.

 

Jim Weir who writes for Kitplanes magazine came up with the idea of marking wires, by using sharpie permanent markers in the colours used for resistor marking on clear heat shrink. Mark the start end with a broad band then use 2 or 3 colours. You will have if I remember right 7 colours to choose from. Make all engine start with 1 and instruments with 2 or whatever takes your fancy. I have a Brother label maker that makes wire labels, but they are about 20mm long tags at right angles to the wire.

 

Give us a photo of the finished job. I wouldn't be game to show mine, after a couple of iterations.

 

 

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a lot of my dymo labels have faded, coloured wiring make sense, its easy as heck to trace.  

 

Using Dymo labels is a bit anal. Humans developed colour recognition before writing, therefore we can identify a colour more easily. Identifying a word takes more brain function, which, when identifying wires by colour code is not really required.

 

 

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Using Dymo labels is a bit anal. Humans developed colour recognition before writing, therefore we can identify a colour more easily. Identifying a word takes more brain function, which, when identifying wires by colour code is not really required.

Yes, but if you have more than a couple of wires you will still need a code to remember which one does what a few months down the track. I like to write something easily identifiable at both ends, even by someone else. For example: MASTER PWR or OIL-P  SNDR. That way, it's real easy to know which circuit you are tracing. Dymo labels go black with heat, so the sharpie works, with clear heatshrink over.

 

 

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Fly tornado said "people seem to go a bit weird when it comes to wiring"

 

Please explain, I wonder what has tickled your "weird" button. I could say the same about some of the remarks posted.

 

 

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the way I see it going with aircraft wiring in a single light aircraft just creates so many issues, like five years after you have built your plane you are on your back in the cockpit floor trying to read a wiring diagram on your back whilst holding a torch in bad light. that 6 point font on your wiring will barely be readable for your old eyes.

 

 

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Hee Hee,  No Battery. No fuses, Three or four wires & still looks a mess.

 

More plastic tubing than wire.

 

spacesailor 

 

 

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the way I see it going with aircraft wiring in a single light aircraft just creates so many issues, like five years after you have built your plane you are on your back in the cockpit floor trying to read a wiring diagram on your back whilst holding a torch in bad light. that 6 point font on your wiring will barely be readable for your old eyes.

I’ve solved both. 

 

I made my dash on telescopic arms so it slides out and tilts forward so you sit upright and work over it. The only issue then is having enough wire length to allow to do so. 

 

And as for labelling I use my laptop and a printer to print the label in size 8 font and (as others have suggested ) I then use clear heat shrink. I acquired an old laser printer so it prints clear crisp text no matter how small and doesn’t fade. Uses very little toner so it lasts forever. 

 

I always label both ends of every wire no matter how short. 

 

Dont need codes or record of what colours mean what. Label says what is. 

 

 

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