How much wire?

[cjensen]

This question is almost guaranteed to get a thousand answers/opinions, but I'd like to try and get an idea for my needs...

Here's my panel-





Couple things missing in that pic...ELT switch and smoke system switch that will go in the middle green blank.

Pretty simple and basic, and I need to get an idea of how much wire of each gauge I'm gonna need for the usuals...18, 20, and 22. Anything else that will be limited in use I can get from work. I just don't know if I need 20 feet or 50 feet...or ?? feet...

Can anyone give me an idea with that info?

I have already run wires for lights and fuel senders...

[MCA]

Chad,

It's hard to just guess. The best approach is to plan all your wiring runs ahead of time. We have planning documents for this, but since you're wiring the old fashion way it's not hard to create your own documents. I'd recommend:
- a document that shows where all the electrical devices, including antennas are located. Download the 3 view images from Vans and paste them into PowerPoint or a drawing program.
- a document that shows the wiring for the "backbone" electrical system - in other words where the contactors, alternators, fuses, ground blocks, battery and big wires go.
- a document that shows the detailed wiring - smaller power wires, serial data wires, ground wires, etc.

Each wire should have a length and wire gauge. Then you can derive what you'll need. And the best part is that in a few years when you want to change something or troubleshoot, you'll have it all documented. I tend to forget those details and have found these drawing to be invaluable.

You can use anything from MS Paint to PowerPoint, to a CAD program. Whatever you're most comfortable with.

[cjensen]

I guess I just need to sit myself down, and draw it out to scale...

Thanks Marc!

[MCA]

Trust me on this one. The time you spend at the desk now will save you lots of time on your back under the panel!

[mannanj]

Originally Posted by MCA

Trust me on this one. The time you spend at the desk now will save you lots of time on your back under the panel!

Marc said a mouthful on this post!

Now a plug for Stein, go ahead and buy a hundred feet of each size wire in different colors for each of the instruments/avionics, etc, etc.

Seriously, buy more than you think you need. You'll probably need it and your friends will love you when they come begging.

Who knows; you might become a repeat offender and need it later.

[Frank]

Don't be shy. After you figure what wire types and gauges you require, procure 100 ft roles (min) of each. You may have enough (or not) but you will use it in the future. While I agree with the planing engineers who are able to define every circuit to the nth degree, I have a tendency to plan about an hour ahead and work accordingly. Ergo, I have found having the materials on hand saves multiple trips to the local aviation hardware store or on-line supplier to be a viable alternative and does not cost any more.

[MCA]

Yes, definintely buy more than planned. It always seems the runs are 3 inches longer than you cut the wire. And wire is pretty inexpensive.