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Be gentle. Rookie question.

claycookiemonster

Well Known Member
Ok. Having gotten reasonably proficient at metal working, I guess it's time to move on to something I know nothing about. Wiring.

There aren't enough colors of wire to be able to code all components, so there seem to be standards: white is power and black is ground. (feel free to jump in any time) and then there are the other wires needed for various devices to control things.

So, theoretical question: Suppose I'm installing a wingtip light which requires a power and a ground and for the sake of argument, there are 3 additional wires required. Assume no local "airframe" grounding. Do I assemble my own twisted bundle with colors to suit me and drag the whole bundle down the conduit to the wingtip, and then leave a large loop at the root end of the wing for final connection to the electrical system?

Is it easier to simply use one gauge of wire, or to custom fit gauge to amps and length of run in every case? Weight versus complexity, right?

Out at the wingtip, when I'm connecting my bundle to the lights, does the ease of removing the wingtip completely justify the addition of a connector out there, or is a large installation loop sufficient?

That's enough for now. Thanks in advance.
 
Well, of course, you’ll need multiple gauges. Line to the starter #2, general avionics 18 or 16 - hugely different. Everyone’s different, you’ll get lots of opinions, so here’s mine: I avoid connectors as much as possible. Ask any avionics guy: ten years down the road it’s connectors that give trouble. If I have to pull a wing I’ll cut wires, re-install with crimp splices.
 
Firstly, I would recommend Bob Nuckoll's book and all the many videos that Stein does - very informative.

Traditionally, all cables were white !

It is the emergence of Stein, Vans and Dynon that have sprouted colour galore which makes things easier.

If you are running cable for say LED lighting to the wingtip, 3/4 core plus shield and earth is readily available through the usual outlets.

Whenever possible on larger current cables, run or group a return earth to a forest of fastons mounted through the firewall and onto a solid earth point firewall forward. Don't forget, the return earth, or earths must be capable of taking the 'outgoing' load.

If you think that wiring is just like running extensions around the shop, an air line, a water pipe etc, there is nothing mysterious about basic cabling.

Now - Ohms, Farads, capacitance..... All a mystery to me, I get a mate in who does a cracking job of keeping the smoke inside the cable, because once it escapes, you can't get it back in again :D
 
I bought a multi color pack of sharpie markers. It is easy to put a colored stripe on white wires, I still label the wires with heat shrink labels because the color does tend to fade but it helps keep track of wires during the routing phase.
 
There is a way to have many red wires that are distinctly different and that’s to use a red wire with a trace. Whilst white may look more like what the big boys use, they also use wire printers so that you know exactly what the wire is all the way along it. We don’t typically have access to such luxuries. I used multiple different colored wires with traces and printed labels at both ends. On the connector side of things, it is possible to get good quality connectors these days that are an order of magnitude better than the molex connectors of old. Deutsch DTM is an example I used a few of, as do many people here, including in my wingtips.

Tom
RV-7.
 
I like the heat-shrink labels

best-heat-shrink-labels.jpg
 
Do I assemble my own twisted bundle with colors to suit me and drag the whole bundle down the conduit to the wingtip, and then leave a large loop at the root end of the wing for final connection to the electrical system?

Is it easier to simply use one gauge of wire, or to custom fit gauge to amps and length of run in every case? Weight versus complexity, right?

Out at the wingtip, when I'm connecting my bundle to the lights, does the ease of removing the wingtip completely justify the addition of a connector out there, or is a large installation loop sufficient?

The answer to all is "42".

Seriously, don't overthink it. Although there are specific rules for subjects which involve physical laws, the rest is common sense and personal preference.

Yes, you'll always check load against gauge and length. It's physical law.

Can you simply install a wire with a larger gauge than strictly necessary? Sure...with the bounds of common sense.

Service loop or connector? Pure opinion. Our 31,442 forum members all have at least one.

I'll share two.

Good wiring will typically go the whole life of the airframe without issues, so in the practical sense, detailed wire labels and color coding are mostly wasted effort. Do it if you love it, just as you might strive for perfect rivets and ripple-free fiberglass. However, electrons don't care about numbers and colors. They care about perfect crimps, corrosion proofing, and vibration support.

Draw and analyze the entire system schematically. Simplify and eliminate rather than adding backups for what-ifs and things that go bump in the night. Then re-draw, this time representing the physical location of components and the routing of wires. That's the drawing you'll build from.
 
Marking or otherwise identifying wires is good practice that makes troubleshooting systems or future modifications like avionics upgrades much simpler then having to trace wiring from pin to pin. I highly recommend that you at lease use color codings, as DH stated, there are 42 and indicate them on your wiring diagram.

From DH, "Draw and analyze the entire system schematically. Simplify and eliminate rather than adding backups for what-ifs and things that go bump in the night. Then re-draw, this time representing the physical location of components and the routing of wires. That's the drawing you'll build from."

The first is a schematic and the second is referred to as a wiring diagram. We build and maintain to wiring diagrams.
 
My experience with wiring my plane was (and still is) filled with overthinking and more than a few bad connectors and poor decisions. I would summarize the lessons I've learn like this.
  • Get some learning in before you plan your first wire run. EAA course is really good, so are their hints for homebuilders videos. Marc Ausman's book is great too.
  • Like DanH mentioned, a detailed schematic with consideration of physical constraints is a must
  • Keep connectors to an absolute minimum, that's what will give you headaches and gremlins
  • Don't cut costs with wire lengths. It isn't worth it. May not need to be service loop lengths, but wires that are too tight to work with are likely to be to tight to handle time and stress.
  • You don't need top end tools, but good tools make it much easier.

Good luck, a great wiring job is its own reward. Then again, do it right from the start so you don't have to count on luck.
 
The answer to all is "42".

Seriously, don't overthink it. Although there are specific rules for subjects which involve physical laws, the rest is common sense and personal preference.

Yes, you'll always check load against gauge and length. It's physical law.

Can you simply install a wire with a larger gauge than strictly necessary? Sure...with the bounds of common sense.

Service loop or connector? Pure opinion. Our 31,442 forum members all have at least one.

I'll share two.

Good wiring will typically go the whole life of the airframe without issues, so in the practical sense, detailed wire labels and color coding are mostly wasted effort. Do it if you love it, just as you might strive for perfect rivets and ripple-free fiberglass. However, electrons don't care about numbers and colors. They care about perfect crimps, corrosion proofing, and vibration support.

Draw and analyze the entire system schematically. Simplify and eliminate rather than adding backups for what-ifs and things that go bump in the night. Then re-draw, this time representing the physical location of components and the routing of wires. That's the drawing you'll build from.


I am on my 5th RV and I concur with what my 'Bama colleague says entirely ;)
 
Labels

Dan! I always read his posts!
You're going to research each product. Might as well see what documentation they have and start saving them. Its very handy when you start drawing schematics.
I like the printed shrink wrap labels as well. The other option is paper slip with clear shrink wrap over.
I do have a connector at each wing tip and tail beacon.
 
wire colors - my opinion

If you go crazy with wire colors, you end up stocking a lot of wire, and you're always short of the one you need.

I basically went with RED= Power (except for heavy cables like the starter where it's obvious).
BLACK = Ground
WHITE = everything else.

I did make a little jig that I could pass a (white) wire through and put a sharpie in the side to make striped wire. That was fairly successful.
 
Wire color

Personally i used Red for power and black for grounds. White on most everything else and used shrink wrap labels. Also used fuse blocks hinged for drop down access behind the panel vs. pull breakers on the panel. Much cleaner and easier.
Also used a spade connecter ground block with an 8 gauge wire connection to the firewall and then to the battery ground. I used the VAns OP wire diagram as a guide to wiring my plane.
 
I spent a career as a avionics/electrical tech, both in the Navy and at a major commercial repair depot.

I don't worry about wire colors. With Dynon and Vertical Power, I bought prefab wire bundles. Its worth the extra expense. For everything else, I wire it my self and use a Dymo label maker to create wire labels on heat-shrink tubing.

And, I still study the books and videos that others mention.

My advice is:

1. Use the correct tooling!

2. Document your electrical system with wiring diagrams and connector "pin-out" tables.

3. Study pictures in others build-logs and search the internet for pictures of aircraft wire bundles. What looks neat, organized and professional is what you should be striving for. But, as others have said, "don't over-think it!"
 
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