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Stainless Steel Firewall Penetration Kit 3/4

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Part# 09-00978


During the testing phase of theall stainless steel heater bypass box, we were astounded at the affects of a simulated engine fire on aluminum firewall components. Watching how fast the aluminum melted away (only 16 seconds) took us by surprise. It became very apparent that fireproofing the firewall was more important than most people realize.

After many months of trial and error, a fireproof pass through was designed. The firewall Penetration Kits offer a fireproof method of getting wires and cables trough the firewall in a clean, professional looking manner that allows easy removal for replacement if necessary.

Testing was initiated on most common methods of wire and cable penetrations available on the market. Simulated engine fire was directed at the stainless shields with rubber grommets, high temperature silicone, eyeball fittings, plain rubber grommets and several untried methods. All failed the fire test with the exception of the steel eyeball, and it only accepts one cable.

The kit comes complete with stainless steel fabricated fitting, fire sleeve tubing, two ALL stainless steel hose clamps and a tube of fire block sealant to seal the ends from moisture and gasses. Includes installation instructions.

  • Fireproof seal of the firewall for penetration of wires and cables.
  • Seals out moisture and gasses.
  • Easy replacement of wires and cables if necessary.
  • Very clean looking installation.
  • Available in three sizes.

To determine the size you need, plan where you want to run your wire and cable bundles. Use a tie strap or twist tie to bundle the wires and cables. Measure what size holes the bundle will fit through and choose the NEXT LARGER size (see installation instructions.) You need enough clearance between the bundle and stainless fitting to push the second fire sleeve into the fitting creating the fireproof, chafe proof seal.

Typical installation. Wires can be run straight out or turned back to attach on firewall reducing vibration.

There are so effective that they received an STC under Advisory Circular AC 20-135 Power plant Installation and Propulsion Systems Component Fire Protection Test Methods, Standards and Criteria.

California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -



In The Box

  • 1 - Firesleeve tube
  • 1 - Stainless Steel Fitting
  • 2 - Hose Clamps
  • 1 - Biotherm 100 Firestop Sealant
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quality, well built and constructed product

Barnabas P Verified Purchase


March 8, 2023

The product is an excellent product and I received it in a timely manner. Thank you.

Lyle M
May 12, 2021

Stupid expensive for what it is , But it works great

Monte H
March 4, 2019

They dont come with the fastener hardware you need to install them, so dont forget to order that too, like I did.

Ryan D
July 17, 2020

Excellent safety, But make sure you recalculate number of wires you can get through the inner sleeve. It is Much smaller than the 3/4 inch it says.

August 10, 2018

Catalog shows 2 pictures, one made sense because there were 3 kits of different sizes and reading below it didnt tell you getting only 1 kit. I didnt even see were you chose the size. Overpriced by 3X

Russell G
January 26, 2019


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

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