FIW stands for Fully Insulated Wire, a Class 180 modified polyurethane enameled copper wire designed to replace traditional triple insulated TIW wire. Produced with multi-layer coating and full online high-voltage testing, it eliminates insulation pinholes to deliver certified reinforced insulation complying with IEC and NEMA standards. FIW4, the most popular grade, balances slim outer diameter and strong dielectric strength for miniaturized coils at lower costs. Its polyurethane base coat features low dielectric loss to reduce heat under high-frequency operation and offers great direct solderability without scraping enamel. The wire has good thermal stability and superior softening breakdown resistance, plus low static friction for smooth automatic high-density winding. Custom wire gauges and self-bond variants are available, and it can be twisted into FIW Litz wire.
| Parameter | Figure |
|---|---|
| Model NO. | FIW4-H |
| Temperature Class (℃) | 180 |
| Enamel Grade | 4 |
| Conductor Diameter (mm) | 0.1280~0.1320 |
| Insulated Outer Diameter (mm) | 0.1780~0.1820 |
| Insulated OD Acceptance Range (mm) | 0.1780~0.1820 |
| DC Resistance (Ω/m20℃) | 1.228-1.307 |
Multi-layer polyurethane coating with full in-line high-voltage inspection eliminates pinholes. FIW4 delivers reliable reinforced insulation to meet global safety standards, serving as a cost-effective substitute for triple insulated wire.
The primer coat features ultra-low dielectric loss to reduce high-frequency heating. It also owns outstanding softening breakdown resistance and stable heat resistance to withstand continuous high-temperature working environments.
Polyurethane insulation enables direct soldering without enamel stripping to simplify processing. Low static friction on the surface supports tight, neat high-speed automatic winding for mini coils.
Various wire gauges and optional self-bond coats are available. It can be twisted into FIW Litz wire, widely used in consumer power supplies, EV electronics, medical devices and communication transformers.
