P R O D U C T   B U L L E T I N


Electrical Insulating Oil


Hydrochem EIO is an electrical insulating oil that provides cooling, insulating, arc quenching, and cleaning properties while meeting the requirements of an ASTM C 3487 Type II fluid.

Hydrochem EIO is a fully inhibited Type II oil, which provides outstanding performance in transformers, circuit breakers, switches, and capacitors.


Hydrochem EIO is designed for use as an insulating medium in multi-circuit junction boxes to protect wiring and other metal components from corrosive agents.

Hydrochem EIO provides a fluid transfer medium for chlorine gas that is produced during the cathodic protection process.  Chlorine byproducts travel from the anode site, through the wiring/insulation, and into the junction boxes.  Without the insulating property of Hydrochem EIO, the chlorine gas reacts with oxygen and severely corrodes the wirings and connections, often leading to mechanical failure after only 6 months.

Hydrochem EIO will provide protection for 2-3 years.

Hydrochem EIO is designed to be used with CPT’s Cathodic Protection Junction Box Model RE-1.



Hydrochem EIO is manufactured from carefully selected base stocks favored by the domestic power industry under stringently controlled manufacturing conditions.  It meets the demanding requirements of the ANSI/ASTM D 3487 specification for electrical insulating oils, including:

  • Excellent impulse strength
  • Excellent oxidation stability
  • Long service life
  • Negative gassing tendency
  • Low power factor
  • Low static charging tendency



Color                                                         Blue

Specific Gravity                                   0.91 max

Weight (lbs/gal)                                           7.59

Pour Point, °C                                       -40 max

Flash Point, °C                                 145 (293 F)

Corrosivity                                    non corrosive

Viscosity, cSt, 40C                                  12 max

Viscosity, cSt, 100C                                  3 max

Water, ppm                                            35 max

Dielectric Strength, kV                             30 min

Aniline Point, C                                         63-83

Interfacial Tension, 25C, dynes/cm           40 min

Neutralization Number, mg KOH/g       0.03 max


Please call 1-800-592-4684 or email Uday Koya if you have any questions.