Transformer Insulating Oil


  • Density (20°C): 0.89g/ml.
  • Color: 0.5.
  • Flash point: 135°C to 140°C.
  • Kinematic viscosity (40°C): 12mm2/sec -16mm2/sec
  • Pour point: -40°C to -18°C.
  • Corrosive sulphur: Non corrosive.
  • Water content: 30mg/kg to 50mg/kg.
  • Dielectric dissipation factor at 90 °C: 0.005.

Salient Features

  • High oxidation stability.
  • High flash point.
  • High dielectric breakdown voltage.
  • Compatibility with materials.
  • Excellent electrical insulation properties.
  • Thermally stable.

Transformer oil (HSN code: 2710), also known as insulating oil or electrical insulating oil, is a specialized type of oil used in electrical transformers. It serves multiple purposes in transformer systems, primarily providing electrical insulation and heat transfer capabilities.

Transformer Oil provides exceptional insulation, cooling, and protection to electrical equipment, ensuring optimal functioning in various industrial and utility applications. Maximizing the efficiency, reliability, and lifespan of transformers. Excellent dielectric properties, effectively preventing electrical breakdown and ensuring reliable insulation throughout the transformer system.

Here is a list of some common transformer oil names:

  • Mineral Oil: Mineral oil is the most common type of transformer oil and is derived from crude oil.
  • Naphthenic Oil: This type of transformer oil is a subset of mineral oil and has specific properties that make it suitable for certain applications.
  • Paraffinic Oil: Paraffinic oils are another subset of mineral oil, and they have slightly different characteristics than naphthenic oils.
  • Silicone Oil: Silicone-based transformer oils are known for their wide temperature range and high dielectric strength. They are used in high-temperature and specialty applications.
  • Ester Oil: Ester-based transformer oils are synthetic and offer improved fire resistance, biodegradability, and environmental safety. They are often used in sensitive or environmentally regulated areas.
  • FR3 Fluid: This is a brand name for a natural ester-based transformer fluid known for its fire resistance and biodegradability.
  • Envirotemp FR3 Fluid: Another brand name for a natural ester-based transformer fluid with similar fire-resistant and environmentally friendly properties.
  • Askarel: Askarel is a brand name for a type of polychlorinated biphenyl (PCB) used in older transformers. PCBs are now banned due to their environmental and health hazards.
  • Hydrocracked Transformer Oil: A type of mineral oil that undergoes hydrocracking to improve its properties and extend its lifespan.
  • Silica Gel Transformer Oil: Some transformer oils are treated with silica gel to remove moisture and impurities, improving their dielectric strength.


  • Insulation in Transformers
  • Dielectric Medium
  • Cooling Medium
  • Bushings
  • Cooling and Heat Dissipation
  • Switch gears

Standards and Certifications

  • IEC 60296
  • ASTM D3487
  • DIN EN 60296
  • IEEE C57.106
  • BS 148

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