Electrical Insulation Materials

 

Fish Paper and Alternatives

Electrical grade vulcanized fiber (also known as fish paper) and its alternative, multi-ply unbleached kraft pulp paper, have been used for decades in electrical insulation applications because of their strength and ease of cutting and shaping. With excellent dielectric strength, temperature resistance, and electrical insulation properties, these products are resistant to aging and to temperatures extremes.

Dielectric Strength: Good

Heat Resistance: Good

Tensile Strength: Excellent

Applications:

  • Motor and switch insulation

  • Arc shields

  • Transformer insulation

  • Electrical hardware

  • Lighting fixtures

 
 

Aramid Fiber Paper (Nomex)

Aramid fiber, more commonly known by the brand Nomex, is used for many electrical equipment applications. It has excellent thermal stability and inherent dielectric strength while being highly resistant to acids, alkalis, solvents, oils, and flames.

Dielectric Strength: Very Good

Heat Resistance: Excellent

Tensile Strength: Good

Applications:

  • Motor insulation

  • Transformer insulation

  • Generator insulation

  • Coil separators

  • Slot liners

  • End fillers

 
 

Flame Retardant Polypropylene Sheet (Formex)

Formex is a flame-retardant polypropylene electrical insulation material that provides excellent dielectric strength. It is chemical resistant and highly resistant to moisture absorption. Used widely to prevent arcing, it is often leveraged as a thermal and/or electrical barrier.

Dielectric Strength: Very Good

Heat Resistance: Good

Tensile Strength: Very Good

Applications:

  • Electrical insulation for electric vehicle onboard chargers

  • Barriers for PC boards

  • Air baffles and wire management for data center control rooms

 
 

Electrical Insulation Films

There are a variety of electrical insulation film options for applications requiring stringent thermal and electrical performance. Mylar®, Kapton®, and Teflon™ are commonly specified for their performance characteristics. These films provide best-in-class electrical and thermal resistance, with each having excellent chemical and mechanical properties and meeting stringent UL 94 flammability ratings.

Dielectric Strength: Excellent

Heat Resistance: Excellent

Tensile Strength: Excellent

Applications:

  • Barrier films

  • Back sheets

  • Electrical insulation

  • Fiber optic cables

  • Flexible printed circuits

  • Anti-corrosive linings

  • High frequency microwave circuitry

  • Cable insulation

  • Photovoltaic cell glazing