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Through the firewall?

MacCool

Well Known Member
Here's a rudimentary question...I need to run some wiring from the hot side of the contactor on one of my batteries through the firewall in order to provide backup power for my EFIS.

How to drill through the firewall? Is it as as easy as just drilling a hole and putting a passthrough with silicone grommet and Firestop, or are there other considerations I'm missing?
 
There are a lot of methods in common use. Even a plastic grommet will last a while under a good intumescent sealant. There are pricy eyeball fittings available from Spruce, etc. A steel tube fitting pumped full of sealant is the most fire resistant. The same tube, with a little bit of sealant at the tip for gas-tightness and covered with a short length of firesleeve is also popular, as it make it easy to go back through the same fitting later without too much effort.

A hot test here: https://vansairforce.net/community/showthread.php?t=72087
 
Regarding the actual drilling, that can be tricky also. Use a small bit, slow rpm, oil, lots of pressure. Enlarge it to size with a Unibit. Stuff makes razor sharp chips - be careful!
 
Regarding the actual drilling, that can be tricky also. Use a small bit, slow rpm, oil, lots of pressure. Enlarge it to size with a Unibit. Stuff makes razor sharp chips - be careful!



Thanks for the tip. I only need this hole to be big enough for a couple of 18 awg wires. I was going to thread some 5/16 stainless steel tubing for the pass-through and squirt some fireseal in there.
 
A steel tube fitting pumped full of sealant is the most fire resistant. The same tube, with a little bit of sealant at the tip for gas-tightness and covered with a short length of firesleeve is also popular, as it make it easy to go back through the same fitting later without too much effort.

Someone posted a link to some stainless flanged tubes awhile back, shower rod holders. Amazon has them---8 bucks for 4 pieces. Came with a nice inner radius at the tube/flange joint.

I am using 3 on the new project. Some Fire Barrier 2000 and all should be good.

https://www.amazon.com/Stainless-UL...611956009&sprefix=shower+rod+,aps,222&sr=8-45
 
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Kid you not

I kid you not. I went to Lowes and found some shower valve handle flanges that I thought would work. But when i tried them on the firewall, they look like bathroom fixtures. I couldn't bear using them. So i broke down and bought a set of these shower curtain stainless fixtures from amazon. Had them in two days. Now i just need to redo my bathroom to use the fixtures I bought; that shouldn't take too much time away from my build.
 
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