Phillips 66® Transformer Oil is a highly refined electrical insulating oil developed for use in oil-immersed transformers, capacitors, tap changers, and circuit breakers where the equipment manufacturer specifies a Type II inhibited oil meeting ANSI/ASTM D3487-09 requirements.

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Features & Benefits

  • Excellent insulating properties
  • High dielectric strength(1)
  • Low power factor
  • Resists oxidation and deposit formation
  • Excellent low-temperature properties
  • Compatible with materials used in transformers
  • Does not contain any PCBs

    (1)Note: In order to maintain its high dielectric strength for use as an insulating oil, the oil must be kept clean and dry. Contamination with even a small amount of water will significantly decrease the dielectric strength. The drums are sealed at the terminal with a blanket of dry air to keep moisture out. The drums should be stored indoors and covered to protect them from dust and debris. If stored outdoors, they should be positioned on their sides or upside down and covered to protect them from exposure to the elements. Every effort should be made to use the entire drum once the seal is broken to help prevent contamination. If contamination is suspected, always inspect the drum and test the oil for dielectric strength before use.


  • Oil-immersed transformers
  • Circuit breakers & switches
  • Fuses
  • Tap changers
  • Other oil-immersed electrical equipment

Technical Details

  • ISO Grade: 10
  • Licenses & Approvals

    Transformer Oil meets the requirements of the following industry and OEM specifications:#ANSI/ASTM D3487-09 Type II Inhibited Oil#British Standard BS 148, Class 1A#Federal VV-I-530A, Class II Specification#GE A13A3A2 (10CA)#IEEE#International Standard IEC 60296#NEMA Type II (obsolete)#Westinghouse Specification PDS 55822AG

    Additional Details

    ISO Grade 10
    Specific Gravity @ 60°F 0.887
    Density, lbs/gal @ 60°F 7.39
    Color, ASTM D1500 0.5
    Flash Point (COC), °C (°F) 160 (320)
    Pour Point, °C (°F) -60 (-76)
    cSt @ 40°C 9.6
    cSt @ 100°C 2.3
    SUS @ 100°F 60.3
    SUS @ 210°F 34
    Viscosity Index 19
    Acid Number, ASTM D974, mg KOH/g <0.01
    Aniline Point, ASTM D611, °C (°F) 75 (167)
    Corrosive Sulfur, ASTM D1275B Non-corrosive
    Dielectric Breakdown Voltage
    Disc Electrodes, 60 Hz, ASTM D877, kV 40
    Oxidation Stability, RPVOT, ASTM D2272, minutes 280
    PCB Content, ASTM D4059, wt % None
    Power Factor @ 60 Hz, ASTM D924
    @ 25°C (77°F), % 0.003
    @ 100°C (212°F), % 0.074
    Water, ASTM D1533, wt % 0.0015
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