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Standard wire color code?

Mike D

Well Known Member
Is there a standard wire color code? I know red = power and black = ground. But beyond this, is there a best practice or standard?

Searched the site, and there was a mention of Stein's code in an article of kitplanes. Does anyone have the info or a link to the article?.
 
Wire Color

I used mostly white wire. If I had to do it again I'd use colored wire and code each circuit. Really hard to keep track of all those white wires.

Doesn't matter how you color-code it as long as you document what you did.
 
My own color code ...

I decided early on I would follow the convention of red=power, black (or green) =ground, but I would also color code the other wires consistently, i.e. in a way that enabled troubleshooting later. For no particular reason, I used yellow for the three strobe power packs (from the switch), red for nav lights from the switch, white for taxi/landing lights, etc. The color code was primarily for wiring to the wings and tailcone, though it carries thru to the toggles in the panel. All power from the busses to switches is red, all grounds are black. I actually ended up with very few white wires.
The downside was the planning necessary to order correct wire quantities in the various colors. Arghhh.
 
Similiar to Terry, I used red for power, black for ground, and white for data.

I think it helps for troubleshooting and helps prevent from hooking up a power source to the wrong pin.

It does require a little more planning to ensure you have enough of the correct color, length, and guage.

bob
 
Another common thing is to use a color --- lets say blue, and a blue with tracer when wiring up things that take a pair of wires. Audio comes to mind, but there are a lot others.

For things that take a three wire setup, color, white tracer, black tracer. Trim motor control or feedback pot for instance.
 
You can certainly choose your own preference as this is the Experimental Category. For most everything, I still refer to the original accepted aviation standard practice source. FAA AC43.13-1b

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2043.13-1B/$FILE/Chapter%2011.pdf
... which (please correct me if I'm wrong) refers one to MIL-C-27500, which specifies two completely different color codes, both of which apply to multi-conductor cables. For single wires, white is specified. The nice thing about standards is that there are so many from which to choose!
 
Here's the problem with deciding to go with a consistent color code - once you go that way, you are all in, which means that you probably can't use a premade harness for your autopilot, EFIS, etc....they might very well have their own code, and then you'll have multiple color meanings within the airplane. I pretty much stick with white wires for avionics harness, although I might use red for power and black for ground as well. There isn't anything wrong with color coding, but if you want the whole airplane to be the same, t is a lot of work, so be prepared...

Paul
 
My solution

I have my system all planned and I'm wiring as I go. I am going the color coding method red power / black ground everythinng labeled (of course) Via shrink wrap label maker... Signal/data are green & white. My solution to the panel harnessesseses :D is the Fast-Stack hub by Approach (all harnesses are white with pig tails matching my color coding scheme) :D

http://approachfaststack.com/

I also, have an awesome contact for Mil-spec wire, so I paid WAY less then most would pay going all white 22759/16/....
 
You can certainly choose your own preference as this is the Experimental Category. For most everything, I still refer to the original accepted aviation standard practice source. FAA AC43.13-1b

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2043.13-1B/$FILE/Chapter%2011.pdf

Regards,

Ken

As Dale said, I'm not sure what you mean when it comes to color....it refers to MIL-C-27500 and also MIL-STD-681 for harnesses. Most of that is colored by wire size or conductor position in a harness it seems from a quick read.

The AC does talk plenty about the details of good wire marking....but could you explain more what your take on wire color from AC43.13-1b is? (I'm thinking you mean use white and label, along the lines of what I'm planning...but not sure.)
 
The AC does talk plenty about the details of good wire marking....but could you explain more what your take on wire color from AC43.13-1b is? (I'm thinking you mean use white and label, along the lines of what I'm planning...but not sure.)

Yes, white with proper labeling is what I was referring to. Visually, it is not as easy for quick identification as color coding the wires but it is the standard in aviation.

The main reason I tend to lean this way is due to my education and background. For the same reason I also only refer to airspeed in knots. It's just habit from formal training and airline experience.

Ken
 
Most people just use the white Tefzel wire and label it.

Are you building or debugging?

A little of both.:)
I am installing a new radio that gets hooked to many of the other gizmos.

When I bought the plane, all wires were white and labeled with sharpie and covered with clear heat shrink. Well, sharpie is not permanent. The ink faded. Very hard to trouble shoot.

When I re-did the whole panel, the pre-made wire harness were color coded, and I just kept with how I interpreted the code.

But as I added more gizmos, the new harness that came with the gizmo did not follow the same code.

So, now they all need to be wired together. So it is a mess.

In my plane, Generally, green, blue, and white (and their striped variations) are signal wires. Of course, red is power and black is ground, with the occasional yellow being power. For some reason solid blue is a 4.8V power. I just followed the GRT color from the EIS harness.

Someone should standardize this experimental thing. (Joking) :)
 
Wire Color Code

FWIW: This is my color code:

WHITE = Large current cable (EXAMPLE: Battery/Starter/Alternator 8AWG or higher)
RED = +12v
BLACK = Ground
YELLOW = Switched +12v signal. These are wires that may or may not have +12v on them. Normally from/to a switch or a contact. (EXAMPLE: Avionics Master relay control, Starter Switch control)
GREEN = Switched Ground These are wires that may or may not have a ground on them. Normally from/to a switch, sensor or contact. (EXAMPLE: Master Relay control, CO2 detector alarm)

54-CompletedWiringHarness_zpsa2de306f.jpg


Even with this basic color code, I still labeled all the wires. I used a standard label machine. Once printed I trimmed the label, placed it on the wire then used clear heat shrink to keep it on. It worked very well.

49--Wiringharnesslabels_zps7bf9fe6e.jpg


:cool:
 
Last edited:
slight thread drift, but not too much ...

Poor Man's Labeling Tip:
If you don't have one o' them fancy wire-labeler gizzies, a great substitute is to write the letters - in extra fine Sharpie - on a piece of small white heat shrink before you apply heat to it. With halfway neat printing, they're very legible and serviceable when you shrink them down.
I tried the tiny computer-printed labels inside clear heat shrink and gave that up after about 15 minutes. W-a-y too much time and trouble.
 
I tried the tiny computer-printed labels inside clear heat shrink and gave that up after about 15 minutes. W-a-y too much time and trouble.

Hmm. OK, I guess it depends on the individual. I did the wire labels inside the clear shrink and didn't give it a second thought (other than having to buy more 1/8" clear shrink from Stein....TWICE :eek:).

In regards to color schemes, do what you like. I chose:

Yellow: Battery (always hot)
Red: Switched 12V
Black: Ground
White: Signal

This stayed true except for a couple of instances such as the starter and alternator cables which are kinda hard to find in anything other than white.
And the GRT EIS harness that comes from GRT with a zillion colors and stripes for identification.
 
One more question on this old thread:
There's no such thing as colored shielded cables, is there? I see that unshielded wire has a lot of colors to pick from, but shielded seems to always have a white jacket (and a fixed set of colors for the wires inside).

Thanks
 
Shrink tubing

Often you don't need to color code the entire wire, you just need to know each end of a single wire in a long bundle.

Short pieces of colored shrink tubing work well for end identifications, and they will also work on the non-colored shielded wire mentioned in the previous post.

The shrink tubing can be used in multiple pieces for a large number of unique combinations.

This idea of mine was picked up by Kitplanes - :)

wire-ident-001.jpg
 
No matter what scheme you use, I would highly recommend adding to your schematics (you are doing schematics, right? :) ) the color codes on the wires (except for perhaps obvious ones like power or ground, but even then, there's no harm in adding the colors...WHT, BLK for power and ground, etc.).

It's much, much easier to just look at a schematic and say...aha, I need to depin the GRY/ORG wire in this connector at pin X, and replace it with GRY/PUR...and so on.
 
I've decided to run coloured wire out to the extremities of the aircraft to assist with wire tracing in the future. This is aided by the fact that Stein has a massive range of colours in 22AWG. It's ok for the big lads to run all white wire given that they print circuit designations along the entire length of the cable, but I don't have any fancy printer, so I'm just labeling at the end. I am running into one problem however, and that is getting varied colours in the shielded cable, either a varied outer colour or internal colours. The reason this is important for me is that the Garmin CAN bus will use a white-white/blue wire, but I also have other items that will require twisted shielded pair running to the same device (eg. autopilot servo to trim servo power wire). Does anyone know anyone that stocks anything other than the white-white/blue twisted shielded pair, as Stein and Spruce only have the one configuration listed? Alternatively, if I can't find anything I'm thinking about running a sharpie down the outside off the wire to assist with ID in the future using one of these:
http://m.aircraftspruce.com/catalog/topages/wiremarkingtool.php
Although $50 is a lot to spend on a piece of plastic. It makes me wish I had a 3D printer.
As another point, does anyone know what the thin plastic strip/ribbon is that is included inside the twisted shielded pair?
Thanks.
Tom.
 
Several years ago Jim Weir did an article in Kit Planes explaining his method of marking, using clear shrink wrap and 7 different marking colours. He used the colours of resistor markings for numbers. He also had a first number for each of several areas of wiring, such as radio, engine etc.
It looked good to me but I had trouble trying to get the markers and in the end laziness made me just use different coloured heat shrink.
I will see if i can find and post the article.
 
I've decided to run coloured wire out to the extremities of the aircraft to assist with wire tracing in the future. This is aided by the fact that Stein has a massive range of colours in 22AWG. It's ok for the big lads to run all white wire given that they print circuit designations along the entire length of the cable, but I don't have any fancy printer, so I'm just labeling at the end. I am running into one problem however, and that is getting varied colours in the shielded cable, either a varied outer colour or internal colours. The reason this is important for me is that the Garmin CAN bus will use a white-white/blue wire, but I also have other items that will require twisted shielded pair running to the same device (eg. autopilot servo to trim servo power wire). Does anyone know anyone that stocks anything other than the white-white/blue twisted shielded pair, as Stein and Spruce only have the one configuration listed? Alternatively, if I can't find anything I'm thinking about running a sharpie down the outside off the wire to assist with ID in the future using one of these:
http://m.aircraftspruce.com/catalog/topages/wiremarkingtool.php
Although $50 is a lot to spend on a piece of plastic. It makes me wish I had a 3D printer.
As another point, does anyone know what the thin plastic strip/ribbon is that is included inside the twisted shielded pair?
Thanks.
Tom.


I picked up a Brady printer online while finishing my plane. It makes labeling very easy and you can purchase heat shrink that can have labels printed as well. I just use the 3/4" labels and wrap them around the wire after printing. A little pricey but well worth it for me since I do a lot of wiring for others.
 
Heat shrink labeler

First of all I am a tool nut. I look for excuses to buy new tools/toys!
Second +/- $100 is in the mud compared to what I am spending on this build. $100 to make my life easier down the road is a no brainer for me.

This is the nice little heat shrink labeler that I used;

http://www.ebay.com/itm/K-Sun-LABEL...941302&hash=item5681e00763:g:RxkAAOxygPtS4qhi

$100 for the labeler and about $22 for heat shrink cartridges. I used 2 1/2 cartridges in the entire aircraft. 1/8"heat shrink will fit from #22 up to 4 conductor shielded. I have one cartridge of 3/16" that was used on about 5-10 heavier wires. Post #5 in this thread talks about the labeling convention I used;

http://www.vansairforce.com/community/showthread.php?t=152279

I also used red for power, green for ground and white for everything else in the main harness. When it came to individual runs (outside of the main harness) I bought about 6 colors and just mixed 'em up to make it easier to follow individual runs (labeled to, of course)
 
Nice find on the heatshrink printer. There aren't many out there that can print for wires as small as our 22AWG.

Back to colour configurations, for the Bosch CAN network, Garmin specifies the use of blue for CAN HI and violet for CAN LO. Given than I can only find tefzel two core 22AWG with white and white/blue, I can only assume that everyone is using the white/blue for CAN HI and white for CAN LO. I'd hate to wire my aircraft back a$$ward to everyone else, and given that this is a 50/50 chance, I've got a pretty good shot at achieving just that.
Can anyone confirm the standard colouring?
Cheers,
Tom.
 
Dymo

Nice find on the heatshrink printer. There aren't many out there that can print for wires as small as our 22AWG.

.....

Cheers,
Tom.

The Dymo series of Rhino printers may be lower cost and will shrink down to our 22 g wire.

https://www.ebay.com/p/Sanford-Bran...d=232553336802&_trksid=p2047675.c100005.m2219

Their 1/4 inch tubes have a minimum diameter of .046" diam and our 22 g wire is 0.050" diameter.

Dymo's heat shrink tube sizing is a bit unusual in that they quote the width of the tubing in a flat state so their 1/4 inch tubing will only fit a wire/cable that is 0.09" diameter or smaller. Buy the tubing cassettes one size larger than you think you need. :)
 
Thanks Gil. Good to know. I would have preferred a Dymo printer anyway because tapes are easier to get here, so it's great to hear that they will shrink down to our 22awg tefzel wires.
Tom.
 
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