View Latest Blog Entries
Testing & Assessment Certification Standard & Regulation Aging Wires & Systems Maintenance & Sustainment Management Conference & Report Protection & Prevention Research Miscellaneous Arcing
Popular Tags
Visual Inspection High Voltage AS50881 MIL-HDBK MIL-HDBK-525 FAR AS4373 Maintenance Electromagnetic Interference (EMI) FAR 25.1707 Wire System Arcing Damage
All Tags in Alphabetical Order
2021 25.1701 25.1703 abrasion AC 33.4-3 AC 43 Accelerated Aging accessibility ADMT Aging Systems AIR6808 AIR7502 Aircraft Power System aircraft safety Aircraft Service Life Extension Program (SLEP) altitude arc damage Arc Damage Modeling Tool Arc Fault (AF) Arc Fault Circuit Breaker (AFCB) Arc Track Resistance Arcing Arcing Damage AS22759 AS22759/87 AS23053 AS29606 AS4373 AS4373 Method 704 AS50881 AS5692 AS6019 AS6324 AS81824 AS83519 AS85049 AS85485 AS85485 Wire Standard ASTM B355 ASTM B470 ASTM D150 ASTM D2671 ASTM D8355 ASTM D876 ASTM F2639 ASTM F2696 ASTM F2799 ASTM F3230 ASTM F3309 ATSRAC Attenuation Automated Wire Testing System (AWTS) Automotive Avionics backshell batteries bend radius Bent Pin Analysis Best of Lectromec Best Practice bonding Cable Cable Bend cable testing Carbon Nanotube (CNT) Certification cfr 25.1717 Chafing Chemical Testing Circuit Breaker circuit design Circuit Protection cleaning clearance Coaxial cable cold bend collision comparative analysis Compliance Component Selection Condition Based Maintenance Conductor Conductor Testing conductors conduit Connector Connector rating connector selection connector testing connectors contacts Corona Corrosion Corrosion Preventing Compound (CPC) corrosion prevention Cracking creepage D-sub data analysis data cables degradat Degradation Delamination Derating design safety development diagnostic Dielectric breakdown dielectric constant Dimensional Life disinfectant Distributed Power System DO-160 dry arc dynamic cut through E-CFR electric aircraft Electrical Aircraft Electrical Component Electrical Power Electrical Testing Electrified Vehicles Electromagnetic Interference (EMI) Electromagnetic Vulnerability (EMV) Electrostatic Discharge EMC EMF EN2235 EN3197 EN3475 EN6059 End of Service Life End of Year Energy Storage engines Environmental Environmental Cycling environmental stress ethernet eVTOL EWIS certification EWIS Component EWIS Design EWIS Failure EWIS sustainment EWIS Thermal Management EZAP FAA FAA AC 25.27 FAA AC 25.981-1C FAA Meeting failure conditions Failure Database Failure Modes and Effects Analysis (FMEA) FAQs FAR FAR 25.1703 FAR 25.1707 FAR 25.1709 Fault fault tree Fixturing Flammability fleet reliability Flex Testing fluid exposure Fluid Immersion Forced Hydrolysis fuel system fuel tank ignition Functional Hazard Assessment functional testing Fundamental Articles Fuse Future Tech galvanic corrosion Glycol Gold Gold plating Green Taxiing Grounding hand sanitizer handbook Harness Design harness protection hazard Hazard Analysis health monitoring heat shrink heat shrink tubing high current high Frequency high speed data cable High Voltage High Voltage Degradation HIRF History Hot Stamping Humidity Variation HV connector HV system ICAs IEC 60851 IEC60172 IEEE immersion insertion loss Inspection installation installation safety Instructions for Continued Airworthiness insulating material insulating tape Insulation insulation breakdown insulation resistance insulation testing interchangeability IPC-D-620 ISO 17025 Certified Lab ISO 9000 J1673 Kapton Laser Marking life limit life limited parts Life prediction life projection Lightning lightning protection liquid nitrogen lithium battery lunar Magnet wire maintainability Maintenance Maintenance costs Mandrel mean free path measurement mechanical stress Mechanical Testing MECSIP MIL-C-38999 MIL-C-85485 MIL-DTL-17 MIL-DTL-23053E MIL-DTL-3885G MIL-DTL-38999 MIL-E-25499 MIL-HDBK MIL-HDBK-1646 MIL-HDBK-217 MIL-HDBK-454 MIL-HDBK-516 MIL-HDBK-522 MIL-HDBK-525 MIL-HDBK-683 MIL-STD-1353 MIL-STD-1560 MIL-STD-1798 MIL-STD-464 MIL-T-7928 MIL-T-7928/5 MIL-T-81490 MIL-W-22759/87 MIL-W-5088 MIL–STD–5088 Military 5088 modeling moon MS3320 NASA NEMA27500 Nickel nickel plating No Fault Found OEM off gassing Outgassing Over current Overheating of Wire Harness Parallel Arcing part selection Partial Discharge partial discharge at altitude Performance physical hazard assessment Physical Testing polyamide polyimdie Polyimide-PTFE Power over Ethernet power system Power systems predictive maintenance Presentation Preventative Maintenance Program Probability of Failure Product Quality PTFE pull through Radiation Red Plague Corrosion Reduction of Hazardous Substances (RoHS) regulations relays Reliability Research Resistance Revision C Rewiring Project Risk Assessment S&T Meeting SAE SAE Committee Sanitizing Fluids Secondary Harness Protection separation Separation Requirements Series Arcing Service Life Extension Severe Wind and Moisture-Prone (SWAMP) Severity of Failure shelf life Shield Shielding Shrinkage signal signal cable Silver silver plated wire silver-plating skin depth skin effect Small aircraft smoke Solid State Circuit Breaker Space Certified Wires Splice standards Storage stored energy superconductor supportability Sustainment System Voltage Temperature Rating Temperature Variation Test methods Test Pricing Testing testing standard Thermal Circuit Breaker Thermal Endurance Thermal Index Thermal Runaway Thermal Shock Thermal Testing tin Tin plated conductors tin plating tin solder tin whiskering tin whiskers top 5 Transient Troubleshooting TWA800 UAVs UL94 USAF validation verification video Visual Inspection voltage voltage differential Voltage Tolerance volume resistivity vw-1 wet arc white paper whitelisting Winding wire Wire Ampacity Wire Bend Wire Certification Wire Comparison wire damage wire failure wire performance wire properties Wire System wire testing Wire Verification wiring components work unit code

Common Questions About Kapton® Wire

Aging Wires & Systems

Key Takeaways
  • Kapton® is the tradename of the polyimide polymer.
  • It is unlikely that an aircraft will need to replace all Kapton® wire. Testing can target the weakest areas.
  • Kapton® wire will last more than 100 hours on an aircraft, regardless of what Wikipedia says.

Love it or hate it, the fact is that Kapton® insulated wires will be on aircraft for at least another couple of decades, and because of this, we should learn to live with the insulation type. Part of living with it is understanding it.

If you have questions that you would like to see answered, please send them to Lectromec or add them to the comments section below. We plan to add to this article as the questions arise.

Why do most Lectromec articles refer to Kapton® as “polyimide”?

Good question. The reason Lectromec uses the term “Polyimide” is that Kapton™ is the trademarked name for the DuPont product. The term polyimide is a more generic term and incorporates all of the other producers of the material that are put into wires and cables.

What is the history of Kapton® wire on aircraft?

For a history of Kapton®, check out this link.

Is Kapton® more prone to arc tracking than other insulation types?

This is one area that Kapton® wire has a weakness; it is a material that is very prone to electrical arcing. To understand this, we must take a close look at the polymer (don’t worry, you don’t have to be a chemist to understand what is going on). The polymer is comprised of carbon, oxygen, nitrogen, and hydrogen; three of those are helpful for promoting arcing events. Other wire insulation types like PTFE contain a great deal of fluorine, an element that performs exceptionally well in squelching arcing events.

Kapton Wire Construction
This is an example of a typical Kapton® wire construction.

Do I need to replace all of the Kapton® wire on my aircraft?

Lectromec has performed wire degradation analysis on dozens of fleets and we have never found a case where full wiring system replacement is necessary. While some areas of the aircraft may show degradation, it is unlikely for this to be the case through the rest of the vehicle.

The insulation is starting to flake off, do I need to replace?

Not necessarily. To address this, it is important to understand the construction of a typical polyimide wire. Polyimide insulated wires that are built to the MIL-DTL-81381 style (the most common polyimide construction) share a common construction. These wires have two layers of polyimide, with an adhesive between the tape wrap layers to provide a seal. These two wraps of polyimide typically yield four layers of insulation. On top of this is a lacquer layer. The primary purpose of this opaque lacquer layer is to provide a surface for printing and wire identification. From an electrical and mechanical perspective, the lacquer layer does not add value to the wire.

The Navy’s guidance on Kapton® wire maintenance MIL-HDBK-522 and inspection states, “Superficial damage to Kapton® wire/cable exterior consists of damage only to the outer jacket (known as topcoat flaking) and does not require repair/maintenance.”

More information is included in this article.

Wikipedia says an FAA study showed that Kapton®, “shows degradation in under 100 hours in a hot, humid environment”. Should I be concerned?

This segment from Wikipedia refers to a wire degradation study the FAA funded back in the 2000s. This research (of which Lectromec participated) sought to find methods to identify stressors and quantify the degradation of various aircraft wire insulation types. Kapton® insulated wire was one of the wire types investigated in this effort. The report (containing vast amounts of data) is still available on the FAA’s website.

Of the examined stresses, several test conditions were examined to accelerate the aging of the samples. When accelerated aging is performed, this usually means that the stressors are pushed beyond the normal limits experienced in aircraft operation. As such, the results of these accelerated aging experiments are unlikely to be directly applicable to in-service conditions.

But what were the conditions that showed, “degradation in under 100 hours in a hot, humid environment”? The Wikipedia entry refers to configuration group #13/Setup#33 which had the following parameters:

  • Temperature: 95oC
  • Relative Humidity: 100% (the wire was submerged in water)
  • Physical Setup: Wrapped around a mandrel 10x diameter

The temperature and physical setup are representative of what can be found on an aircraft, but what about the 100% humidity? How many parts of the aircraft are regularly submerged in near boiling water? While the data show a rapid degradation, it is unlikely to be found during an aircraft’s service life. As of the publishing date of this article, the number of submersible aircraft is still limited.

Are there ways to determine the health of a Kapton® wire?

Kapton® wire degradation has been an area of research Lectromec has done extensive work in. The typical method Lectromec uses for degradation analysis is the inherent viscosity method (see detailed information here and a case study on its application here) In short, the chemical process quantifies the material degradation which is then used, along with aircraft use and life information, to predict the remaining reliable service life.

This technique has been applied to several fleets as part of EWIS health monitoring, support for the EWIS portion of their MECSIP program, or helping to generate data for fact-based EWIS maintenance and sustainment planning.


There are a lot of misconceptions about Kapton® wire and some of this has been justly earned. Lectromec plans to progressively add to this article, so if you have any questions, please feel free to contact us directly or post your question in the comments section below.

Michael Traskos

Michael Traskos

President, Lectromec

Michael has been involved in wire degradation and failure assessments for more than a decade. He has worked on dozens of projects assessing the reliability and qualification of EWIS components. Michael is an FAA DER with a delegated authority covering EWIS certification and the chairman of the SAE AE-8A EWIS installation committee.