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Color coding wires: when to stop?

Steve Crewdog

Well Known Member
Patron
I'm redoing some wiring and where it's possible I'm taking the opportunity to change from white to colored wire (red/black, blue for audio, yellow for signal, etc). Some things are simple, I'm adding red or black heat shrink to the battery wires, but after that, the question is, where do you stop?

For instance, I've got 4 switches on my left panel, 3 of which have circuit breakers. So I have wires going from the power buss into CBs, from the CBs to the switch, then from the switch to the device (generator, alternator, main fuel pump), if I changed them from white -> red, instead of a mass of white wires I'd have a mass of red wires. Plus wires going from the starter switch underneath to a terminal strip, which then distributes to various other functions.

If I understand it right, until the power is used a wire is technically "hot", and should/could be coded red, then on the return from the device it would be black for ground.


Not sure if changing everything in this area from white to red is an improvement or not, or is there a point you would draw the line, like only red wires into the CBs, then white from there.


Thoughts?
 

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Builders preference for this. I made all power wires red, all ground wires black, all data/signal wires white. Further more specific identification indicating where the wire originates and where it terminates was made using labels at each end.
 
Builders preference for this. I made all power wires red, all ground wires black, all data/signal wires white. Further more specific identification indicating where the wire originates and where it terminates was made using labels at each end.

Similar on our plane, signal and data wire was pretty much as supplied from GRT----all nicely color coded. GRT supplies color coded wire for all connections and we did not need all in our installation, so I re-purposed some of the unused wiring and made note of these in our "as built" book.
 
To me, after 40 years of wiring similar hardware, wire color codes have their place in some repetitive applications but when you are terminating both ends and have labeled them as you have it’s not a big advantage. Nothing looks nicer than an all white wire bundle.
 
I did what Erich did.

By labeling each device's wires, and referring to the wiring diagram, it's easy to tell what's what, even if multiple devices are bundled together.

Dave
 

Ah, ok.

I figure SteinAir would not sell something that was not good enough for flight.


[thread drift]
Stein also sells SPST Honeywell switches @ $22 each. https://www.steinair.com/product-ca...ice-desc&filter_pole-throw-configuration=spst

Thoughts about Honeywell switches @$22 each vs Carlings @ $5.50 each, all?
[/thread drift]
 
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I’m betting this turns into one of those popcorn threads but.. just buy one of the more expensive switches and compare the switch action and finish. I did and threw away the Carling.
 
I’m betting this turns into one of those popcorn threads.

Yep. Maybe I should spilt them?

In the meantime, it's raining like crazy at my hangar, and I just fired up the Traeger. Yams are smoking now. Menu will be selections from the Ron Swanson Food Pyramid of Greatness.
 
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The really bad switches are those that use rivets to conduct electricity, especially if the rivets go through plastic.
The plastic will flow over time which causes a lose connection.
 
Color code

Like an old builder once told me: " never miss an opportunity to install a nut plate"
I followed his advice and came up with my own, never miss an opportunity to color code my wiring.
Much like Mike S. I used the template coding from a Dynon harness and applied it to everything else. I did also apply shrink labels to identify the source of the wire. Very clean looking harness and very easy to trace and find anything even without a schematic.
Nothing looks nicer than an all white wire bundle.
To each his own but to me, "amateur" nothing looks worse than an all white wire bundle. Can't imagine having to find a wire in the middle of a white wire bundle, so much easier when you are looking for color instead of a faded number.
 
I suspect that riveted switch lugs can also become loose from fitting and removing faston connectors, especially if somebody wiggles and pulls hard on the faston to get it off.
Bob Nuckolls recommends faston (vs screw) connectors, yet it seems difficult to find non-riveted faston toggle switches. I haven't been able to find the Honeywell TL switches with faston terminals.
 
Similar on our plane, signal and data wire was pretty much as supplied from GRT----all nicely color coded. GRT supplies color coded wire for all connections and we did not need all in our installation, so I re-purposed some of the unused wiring and made note of these in our "as built" book.

GRT's wire color scheme is very helpful.

I bought a lot of different colored wire in different sizes, but the number of combinations grows quickly.

In the end, I used labels at each end of mainly white wire. In my small aircraft, I have not needed to "trace" a wire or find a particular wire inside a bundle - I always start from one end or the other, which is labeled.

I don't have one, but this looks like an interesting tool:

https://www.aircraftspruce.com/catalog/topages/wiremarkingtool.php

You could make up your own color codes for whatever wire you run, and probably do a lot in place.

12-02497.jpg
 
A couple of other color codes to add as suggestions...

1) yellow = lighting circuits (radio and switch backlights, dimmers etc)

2) light blue = audio ground

3) purple = it was waaaay too late at night when I wired this! :)
 
Ah, ok.

I figure SteinAir would not sell something that was not good enough for flight.


[thread drift]
Stein also sells SPST Honeywell switches @ $22 each. https://www.steinair.com/product-ca...ice-desc&filter_pole-throw-configuration=spst

Thoughts about Honeywell switches @$22 each vs Carlings @ $5.50 each, all?
[/thread drift]

Neither are rated for DC, which is more challenging to interrupt. I've had the fast-on Carlings for 21 years/1800 hours with only one failing early on. Doesn't mean they won't all fail the next time, but just a data point. Bought on Nuckoll's recommendation in about 1999 or so. I do have a higher quality master switch. Upgrading to the Honeywell is almost a round-off error, given the % cost of the entire build. Of course, the same can be said about almost everything...
 
Sharpie ink fades and disappears over time, perhaps 5 or 10 years.

Turns out it rubs off, too. Working on a wire bundle I colored red 2 years ago, some of the red sharpie has rubbed off onto other wires. :mad: I had ordered some red 20 ga but was debating if I should go to the hassel of replacing those red sharpied wires with real red wires, question answered.
 

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Neither are rated for DC, which is more challenging to interrupt. I've had the fast-on Carlings for 21 years/1800 hours with only one failing early on. Doesn't mean they won't all fail the next time, but just a data point. Bought on Nuckoll's recommendation in about 1999 or so. I do have a higher quality master switch. Upgrading to the Honeywell is almost a round-off error, given the % cost of the entire build. Of course, the same can be said about almost everything...

MICRO SWITCH Military-Grade Toggle Switches, TL Series

Amp rating Up to 20 A, ac and dc capability
 
Rocker switch with VPX

I have the standard aircraft grade toggles and I dont like the looks. They work find and I most likely will not make any changes.

But, I have the VPX power system so the switches only control the VPX system - not the power to each device. Is there a reason why I shouldnt change to a simple rocker switch? I would have at the start but I couldnt figure out how to make them lighted with the VPX system. I have seen wiring diagrams that have that problem figured out.

Any thoughts from someone with the VPX Power system?
 
well, this turned into two questions I guess.

My avionics guy built up my main wire bundle with red power & black ground wires. Lots of white signal wires, brown for other stuff, yellow for lights, etc. He also labeled every wire on both ends with labels in clear heat shrink. That's going to be invaluable for future upgrades of troubleshooting.

For all the stuff I've added, I've tried to do red=power black=ground, but I don't sweat all the other pretty colors. I didn't do clear over labels either. I had about 6' of while heat shrink that I came up with surplus from the yard store so i write labels with sharpie on little pieces of it and label both ends of whatever I install.

Sharpie won't wipe off heat shrink like it will wire insulation. Especially after its baked on with a heat gun.

I did buy matching color coded wire for the 10 wires coming out of the stick grip, but that was only because my system with premade bundles has it spliced into the stick pigtail under the pilot seat and then running up to the panel where it plugs into a connector into the garmin system. It was easier to keep the wiring out of the stick all consistent instead of changing horses in teh middle of the stream in that case.

FYI- I think all white bundles look classy, but if they aren't marked in some way, they are a royal pain to troubleshoot. Cessna has all white bundles, but they also have a machine on their wire balcony that laser prints point-to-point wire data (system, connector, pin position) on every wire all along the entire length of every wire when the bundles are fabricated.

As far as switches, every switch in my RV is Honeywell except the prefab flap switch from Stein, which I believe is Carling. That one is on the end of the row of switches and easy to get to, so I didn't sweat it.

Mostly, I think that you get what you pay for. I don't mind saving a buck and it's not like it's big deal if you lose the nav light switch someday, but in my case, there is limited access behind the panel where the switches are located. If one in the middle of the row goes bad, the only way to R&R it is to pull out it's outboard neighbors first so I wanted to minimize the chances that I'd end up having a huge hassle replacing a hard to access one in a few years.
 
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I have the standard aircraft grade toggles and I dont like the looks. They work find and I most likely will not make any changes.

But, I have the VPX power system so the switches only control the VPX system - not the power to each device. Is there a reason why I shouldnt change to a simple rocker switch? I would have at the start but I couldnt figure out how to make them lighted with the VPX system. I have seen wiring diagrams that have that problem figured out.

Any thoughts from someone with the VPX Power system?

The obvious reason to go with toggles over rockers is that it's a lot easier to drill a hole for a toggle switch than a rectangle for a rocker. but they do look cool :)
 
...

Sharpie won't wipe off heat shrink like it will wire insulation. Especially after its baked on with a heat gun.
...

That's a good tip! Also, perhaps other brands of permanent marker work better? (trying to defend my suggestion above! :D )

... Cessna has all white bundles, but they also have a machine on their wire balcony that laser prints point-to-point wire data (system, connector, pin position) on every wire all along the entire length of every wire when the bundles are fabricated.
...
This is what we all need in our shops - laser wire markers!
 
That's a good tip! Also, perhaps other brands of permanent marker work better? (trying to defend my suggestion above! :D )

This is what we all need in our shops - laser wire markers!

Aircraft spruce offers a laser marking service for wires you purchase from them. Not sure if there’s a minimum order or the cost but might be worth a look.
 
Switches made for heavy current could have silver plated contacts. Switches made for signal current, say 3 amps or less may have gold plated contacts for corrosion resistance. Switches need to be exercised to wear away corrosion.
 
That was a fun 2 days. I think it was totally worth it.
 

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Color coded wiring

I keep looking at this thread hoping to find some reply on color coded wiring and we are now well into switches.
Maybe I could contaminate the thread some more with the addition of mogas vs avgas....
Major thread creep, sheeesh.
 
Another input on wire colors

I keep looking at this thread hoping to find some reply on color-coded wiring and we are now well into switches.
Maybe I could contaminate the thread some more with the addition of mogas vs avgas....
Major thread creep, sheeesh.

Below is my attempt at a color code used (where feasible) in total rewire of RV8.

RED = Power
Black =Ground (although is some cases this ended up WHITE_
YELLOW = Variable Control voltage (e.g.. lighting_
BLUE = Digital Control Data (e.g. RS-232 etc.)
WHITE = All else NOT specified by a manufacturer
MULTICOLORS = Harness supplied by manufacturer (in my case GRT)

Not asked but I also tried to color code the switches with little rubber booties:

RED = Battery (Main and AUX)
WHITE = Lights
GREEN = Electronic Ignition (with a green LED)ower
BLUE = Smoke System Arm Power (was YELLOW)
YELLOW = Alternator (Between RED Main and AUX)
YELLOW = Avionics (Between RED AUX and bank of WHITE Lights)
YELLOW = Autopilot (Between BLUE Smoke and BLACK APRS)
BLACK = APRS Tracking

The above is from memory, so I may be off somewhere but you get the picture. I am slowly adding (as appropriate) the same color LEDs for some things.
As an example, I know that if I ever see anything GREEN lit up after leaving the plane, I FORGOT to turn of the Electronic Ignition Power! :)

Hope this helps a little.
 
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