View Latest Blog Entries
Testing & Assessment Certification Standard & Regulation Aging Wires & Systems Maintenance & Sustainment Protection & Prevention Management Conference & Report Research Miscellaneous Arcing
Popular Tags
Visual Inspection High Voltage AS50881 MIL-HDBK MIL-HDBK-525 FAR Electromagnetic Interference (EMI) AS4373 Maintenance 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 installation 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 EMI 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 Filter Line Cable 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 distance 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

Maximizing Electrical Component Performance

Certification Testing & Assessment

Most components for electrical systems will have an accompanying product specification or product information sheet. These information sheets contain a lot of information that include mechanical, thermal, and electrical performance and this information is regularly used by engineers to make technical decisions. This performance information is necessary to reduce engineering time and avoid the need to independently evaluate every single component.

However, is the right information being conveyed to the engineer? For example, many aircraft electrical components include a maximum voltage, maximum temperature, and component specific information (e.g. trip time for circuit breakers, DO-160 humidity thresholds, etc.). But is it possible that this information would be misunderstood and lead to improper engineering decisions?

Consider this: an example wire’s voltage rating is 600VAC with a temperature rating of 260°C. Should it be expected that the wire should have a long service life if it is constantly used at 600VAC in a 260oC?

To answer that question, we must first go through how components are tested.


When components are tested for qualification, the test is performed in such a way to evaluate a single element of the component performance. For example, when a wire insulation’s electrical properties are evaluated, such as insulation resistance, this is often at ambient temperature either on a virgin sample or after some stress, such as high temperature exposure.

The key here to remember is that the insulation resistance, and many of the other properties identified on product specification sheets, is not monitored or evaluated while the wire is under stress. It is perfectly rational to assume that the properties will change a hundred different conditions, but how much will it change is uncertain and nearly never provided with the product information.


One of the first properties to degrade is with mechanical stressing. For example, the standard testing for wire is performed at multiple temperatures, but for some wire types it is not. Lectromec has performed this testing and found as much as a 90% reduction in cut through performance between ambient to maximum rated temperatures.

As one would anticipate, as the temperature is increased, the mechanical performance of polymers degrades. But a 90% reduction suggests that nearly any mechanical compression of the wire (such as under an undersized clamp) at that temperature would result in failure. This is because when a wire is temperature rated the test requires only thermal exposure without mechanical stressing (full test information here).

Product Manufacturers

To the defense of the product manufacturers, there are far too many permutations of environmental and operational conditions to be shown on a product specification sheet. Many of the components that are produced have product sheets that contain a lot of information and should be used as a baseline for first round product selection which is then subsequently reduced through additional component evaluation.

Maximum bounds for wire performance
The performance and ultimate reliability of any electrical component is based on the design, manufacturing, use, and maintenance. Understanding that product specifications provide an idealized performance description is the first step to designing a safe system.

As highlighted in the previous section, it is important for engineers to know that the product performance information is often under idealize conditions. When placed in real world applications, it is necessary to derating the product performance to allow for the margin of error and for the safety factor.

Combination of Environmental Factors

A graphical representation of this is shown in the graphic where a given wire/cable has maximum performance criteria for a combination of operational environments. In the figure, we see two example configurations.

Figure Location Description of Performance Representative Location on Aircraft
Orange Cable with a more limited mechanical electrical performance but a very high maximum temperature rating. Cable routed in a high temperature environment that is electrically derated and it has been derated such that there is less current on the circuit than would be in a lower temperature environment. Further, to prevent insulation degradation, the cable’s movement is limited through additional clamps and harness protection.
Blue More mechanical and electrical performance is desired than the orange configuration, but the maximum operational temperature of the wire is limited. Cable is used for a high current application, but placed in a relatively benign environment

In both the orange and blue dots indicate maximum long-term reliable performance for the component for a given set of environmental conditions. As such, the maximum performance criteria for any electrical component should be considered as a combination of multiple factors. To go beyond this would reduce the overall service life of the electrical component. This is perfectly fine, however, this should then be associated with life limiting and having this addressed as part of either an EZAP program or instructions for continued airworthiness (ICA).


While product information sheets often contain a lot of good information, the information needs to be taken with the knowledge that it is gathered from a particular set of tests. It is often necessary to do additional evaluations to ensure that the product is proper for the desired application. This is not necessary if the product is being used in scenarios well below the limits to which it specified, but as the product is used closer to those limitations it is better to evaluate during design them before use than when the product is in the field. Lectromec can help you identify the best product for your application. Contact us to find out more.

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. In September 2014, Michael was appointed as an FAA DER with a delegated authority covering EWIS certification.