In our This vs. That series, we clarify some of the small details that differentiate products with similar functions. This series is meant to make it easier to know which product is the optimal choice for a specific situation. This article differentiates ETFE and XL-ETFE insulation materials so that you can figure out exactly which type of insulation will work best in your next application.
ETFE and XL-ETFE are both common insulation materials used in wires for the aerospace industry. Aerospace wires are used in tough applications where severe temperatures are encountered. Both ETFE and XL-ETFE are thermal aging, solder, and moisture resistant. These materials are used as insulation in slants within M22759 military wire. MIL-W-22759 has since been replaced with the classification SAE AS22759 but is still commonly referred to by its mil-spec. The slants that will be compared in this post are /16-/19 which uses ETFE and /32-/35 which uses XL-ETFE.
What is ETFE?
ETFE is the acronym for Extruded Ethylene Tetrafluoroethylene. It is wire insulation used primarily in electronic aerospace and transit applications. These applications usually call for cable that is mechanically tough and flame retardant, but lightweight. The MIL-Spec slants using this insulation are M22759/16-/19. They are primarily used in aerospace/aircraft applications where military specifications are needed.
| Slant | Conductor | Insulation | Voltage | Temp. Rating |
|---|---|---|---|---|
| M22759/16 | Stranded Tinned Copper | ETFE | 600V | 150°C |
| M22759/17 | Silver Plated Copper Alloy | ETFE | 600 V | 150°C |
| M22759/18 | Stranded Tinned Copper | ETFE | 600V | 150°C |
| M22759/19 | Silver Plated Copper | ETFE | 600V | 150°C |
What is XL-ETFE?
XL-ETFE is the acronym for Cross-Linked Extruded Ethylene Tetrafluoroethylene. It is wire insulation that is used primarily in avionic and airframe applications. These applications typically demand mechanically tough and flame retardant cable. In addition, XL-ETFE, a type of thermoset insulation, provides excellent fluid, oil, and moisture resistance. Cross-linking also creates increased stability at higher temperatures. The MIL-Spec slants that use XL-ETFE are M22759/32-/35.
| Slant | Conductor | Insulation | Voltage | Temp. Rating |
|---|---|---|---|---|
| M22759/32 | Tinned Copper | XL-ETFE | 600V | 150°C |
| M22759/33 | Silver Coated High Strength Copper Alloy | XL-ETFE | 600V | 200°C |
| M22759/34 | Tinned Copper | XL-ETFE | 600V | 150°C |
| M22759/35 | Silver Coated High Strength Copper Alloy | XL-ETFE | 600V | 200°C |
How Do They Compare?
As you can see, there is some overlap between ETFE and XL-ETFE insulated wires. Both are aerospace wires with a voltage rating of 600V, use similar conductor material, and meet military specifications.
Even though ETFE and XL-ETFE are similar, they do have some very noticeable differences. The main difference is that one is cross-linked and the other is not. The cross-linking in slants /32-/35, when using silver coated/plated copper alloy as the conductor, gives them an overall higher temperature rating than slants /16-/19. Slants /16-/19 with silver-coated/plated copper alloy are rated to 150°C, while in slants /32-/35, those that use silver coated/plated copper alloy are rated to 200°C. Cross-linking also provides greater stability at these higher temperatures than its regular counterpart.
If you’re unsure about what cable you’ll need in order to meet the needs of your application, consult with one of Allied’s knowledgeable sales reps by submitting an RFQ.