Transformer Oils


Calumet has over 25 years of experience producing high-refined, clean, and stable electrical insulating fluids. The CALTRAN™ and VOLTESSO™ line of naphthenic transformer oils is a portfolio of customized products, formulated to fully meet specific global specifications – thus providing customers flexibility in choosing the transformer oils that meet their specific requirements. Calumet is a long standing participant in the Annual DOBLE Survey on transformer oil.


Our line of transformer oils are available in six grades and provide excellent dielectric properties, high thermal stability and good oxidation resistance.
  • Rapid heat transfer properties
  • Outstanding low temperature properties without the need for pour point depressants
  • Miscible with all comparable hydrocarbon-based transformer oils
  • Meets ASTM D3487 specifications for Type I and Type II application specifications

CALTRAN™ 60-00 Group U

Uninhibited transformer oil provides protection without the use of additives.
  • Meets IEC 60296, ed. 4, 2012 general specifications for uninhibited oil
  • Meets JIS C 2320 Electrical Insulating Oils (including Amendment 1, 2010)
  • Verified by an accredited independent laboratory
  • Meets IP 346 and Modified Ames criteria for biological safety
  • Miscible with insulating oils meeting IEC 60296: 2012 specifications


Our line of transformer oils are recommended for use in electrical applications subject to extremely cold start-up conditions or those with forced oil cooling systems.
  • Excellent low temperature fluidity
  • Exceptional insulating properties and corrosion control
  • Meets CAN/CSA-C50-14 specifications

Calumet can custom blend to meet specific customer requirements

For product inquiries, contact our Product Support team at +1.800.437.3188