Transformer Oils



Calumet has more than 25 years of experience producing highly refined, clean and stable electrical insulating fluids. The CALTRAN 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.

Developed in-house by Calumet’s R&D group, CALTRAN transformer oils have excellent dielectric properties, high thermal stability and good resistance to oxidation. CALTRAN transformer oils fully meet ASTM D3487 specifications for Type I and Type II mineral insulating oil in electrical apparatus.


CALTRAN C50 insulating oils are developed using high-quality base stocks to deliver a product that provides excellent performance in electrical service. CALTRAN C50 insulating oils are designed and manufactured to provide cooling and insulating properties as well as promote resistance to oxidation and sludge formation.

CALTRAN C50 insulating oils are recommended for use in electrical applications subject to extremely cold conditions and forced oil cooling systems. Potential applications include load transformers, tap changers, switches and circuit breakers required to operate at ambient temperatures below -25 °C.

CALTRAN C50 insulating oils meet or exceed Canadian Standards Association C50-14 specifications for Class A and Class B, Type I and Type II insulating oils.

CALTRAN™ (IEC 60296:2020, Ed. 5)

CALTRAN 60-00 TVBU is a superior naphthenic transformer oil that fully meets IEC 60296:2020 general specifications for uninhibited, unused oil for transformers and JIS C 2320 Electrical Insulating Oils (including Amendment 1, 2010).

CALTRAN 60-40 TVBI is a superior paraffinic transformer oil that fully meets IEC 60296:2020 general specifications for inhibited, unused oil for transformers.

Calumet can custom blend to meet specific requirements

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

  Specially Formulated For Your Application Needs